the story of the herschels a family of astronomers. sir william herschel sir john herschel caroline herschel. "stars numberless, as thou seest, and how they move; each has his place appointed, each his course." milton. 1886 prefatory note from the best available sources have been gathered the following biographical particulars of a remarkable family of astronomers--the herschels. they will serve to show the young reader how great a pleasure may be found in the acquisition of knowledge, and how solid a happiness in quietly pursuing the path of duty. on the value of biography it is unnecessary to insist. it is now well understood that we may learn to make our own lives good and honest and true, by carefully and diligently following the example of the good and honest and true who have gone before us. and certain it is that the lessons taught by the lives of the herschels are such as young readers will do well to lay to heart. contents chapter i. the study of astronomy a source of intellectual pleasure--by contemplating the heavens, the mind is led to wonder and adore--a proof of the existence of a creator is afforded by creation--"we praise thee, o lord!"--the beauty of nature--intellectual curiosity--"order is heaven's first law"--value of astronomical study chapter ii. herschel's parents--the two brothers--a musical family--an inventive genius--the brothers in england--herschel as an organist--a laborious life--mechanical ingenuity of william herschel--telescope-making--a sunday misadventure--constructing a twenty-foot telescope--a domestic picture--discovery of a new planet--herschel's combined musical and astronomical pursuits--a thirty-foot telescope--casting the mirror--an explosion chapter iii. the house at datchet--housekeeping details--a devoted sister--life at datchet--herschel's astronomical observations--testing and trying "eyepieces"--the colossal telescope--miss herschel's accident--removed to slough--constructing a forty-foot telescope--brother and sister--heroic self-denial--occupations at slough--royal liberality--an astronomer's triumphs--about the nebulae--investigation of the sun's constitution--the solar spots, and their influence--physical constitution of the moon--lunar volcanoes--arago's explanation--herschel's study of the planets--satellites of saturn--discovery of uranus--and of its six satellites--study of pigott's comet and the comet of 1811--description of the latter--an uneventful life--herschel's marriage--his honours--extracts from his sister's diary--decaying strength--herschel removes to bath--last days of an astronomer--illustration of the ruling passion--death of sir william herschel--his achievements chapter iv. birth and education of sir john herschel--honours at cambridge--first publication--continues his scientific studies--his numerous literary contributions--his devotion to his father's reputation--the forty-foot telescope--herschel's observations on the double and triple stars--on the refraction and polarization of light--catalogue of nebulae and star-clusters--voyage to cape town--letter to miss herschel--study of the southern heavens--return to england--distinctions conferred upon him--his "familiar lectures on scientific subjects"--his description of volcanoes and earthquakes--continual changes in the configuration of the earth--violent earthquakes--phenomena of volcanic eruptions--in mexico--in the island of sumbawa--herschel's theory of volcanic forces--his character chapter v. caroline herschel's devotion to her brother william--her grief and solitariness at his death--reflections on the mutability of human things--aunt and nephew--a parsimonious government--miss herschel's gold medal--south on sir william's discoveries--on miss herschel's devotion--her own astronomical discoveries--her life at hanover--her wonderful memory--anecdotes of sir john herschel--correspondence between aunt and nephew--the path of duty--sir john's visit to miss herschel--reminiscences of early years--a nonogenarian--a christmas in hanover--last days of caroline herschel--her death--her epitaph the story of the herschels. chapter i. of all the sciences, none would seem to yield a purer intellectual gratification than that of astronomy. man cannot but feel a sense of pleasure, and even of power, when, through the instruments constructed by his ingenuity, he finds himself brought within reach, as it were, of the innumerable orbs that roll through the domains of space. he cannot but feel a sense of pleasure, and even of power, when the telescope reveals to his gaze not only the worlds that constitute his own so-called solar system, but the suns that light up the borders of the universe, system upon system, sun upon sun, covering the unbounded area almost as thickly as the daisies cover a meadow in spring. he cannot but feel a sense of pleasure, and even, of power, when he tracks the course of the flashing comet, examines into the physical characteristics of the sun and moon, and records the various phases of the distant planets. but if such be his feeling, it is certainly tempered with awe and wonder as he contemplates the phenomena of the heavens,--the beauty of the stars, the immensity of their orbits, the regularity with which each bright world performs its appointed course, the simplicity of the laws which govern its motions, and the mystery which attends its far-off existence. it has been, said that "an undevout astronomer is mad;" and if astronomy, of all the sciences, be the one most calculated to gratify the intellect, surely it is the one which should most vividly awaken the religious sentiment. is it possible to look upon all those worlds within worlds, all those endless groups of mighty suns, all those strange and marvellous combinations of coloured stars, all those remote nebulous clusters,--to look upon them in their perfect order and government,--to consider their infinite number and astonishing dimensions,--without acknowledging the fulness of the power of an everlasting god, who created them, set them in their appointed places, and still controls them? is it possible to be an astronomer and an atheist? is it possible not to see in their relations to one another and to our own little planet an almighty wisdom as well as an almighty love? could any "fortuitous concourse of atoms" have strewed the depths of space with those mighty and beautiful orbs, and defined for each the exact limits of its movements? alas! to human folly and human vanity everything is possible; and men may watch the stars in their courses, and delight in the beauty of sun and moon, and perceive all the wonders of the sunrise and all the glories of the sunset, without any recognition in their hearts of him who made them--of him in whom we and they alike live and move and have our being! yet it is not the less true that only the devout and thankful heart can adequately and thoroughly sympathize with the love and wisdom and power which are written in such legible characters on the face of heaven. astronomy gives up _all_ its treasures only to him who enters upon its study in a reverent spirit. it affords the purest intellectual gratification only when its pursuits are undertaken with a humble acknowledgment of the littleness of man and the greatness of god. half the wonder, half the mystery of creation is lost, when we fail to recognize the truth that it is governed by eternal laws springing from an almighty intelligence. take the creator out of creation, and it becomes a hopeless puzzle--a dreary problem, incapable of solution. but we restore to it all its brightness, all its beauty, all its charm, when we are able to lift up our hearts with the psalmist and to say: "praise ye the lord. praise ye the lord from the heavens; praise him in the heights. praise ye him, sun and moon: praise him, all ye stars of light. let them praise the name of the lord: for his name alone is excellent: his glory is above the earth and heaven." and it is to be observed that the soul cannot be satisfied without this religious view of nature. the heavens and the earth are as nothing to man, if they do not excite his awe and call forth his thanksgiving. we might almost suppose that it is for this purpose that the sea rolls its waves on the shore, and the violet smiles by the wayside, and the moon floods the night with its silver radiance. as a recent writer has observed,[1] the beauty of nature is necessary for the perfection of _praise_; without it the praise of the creator would be essentially weakened; our hearts must be roused and excited by what we see. "it may seem extraordinary," adds our authority, "but it is the case, that, though we certainly look at contrivance or machinery in nature with a high admiration, still, with all its countless and multitudinous uses, which we acknowledge with gratitude, there is nothing in it which raises the mind's interest in nearly the same degree that beauty does. it is an awakening sight; and one way in which it acts is by exciting a certain curiosity about the deity. in what does god possess character, feelings, relations to us?--all unanswerable questions, but the very entertainment of which is an excitement of the reason, and throws us upon the thought of what there is behind the veil. this curiosity is a strong part of worship and of praise. to think that we know everything about god, is to benumb and deaden worship; but mystical thought quickens worship, and the beauty of nature raises mystical thought. so long as a man is probing nature, and in the thick of its causes and operations, he is too busy about his own inquiries to receive this impress from her; but place the picture before him, and he becomes conscious of a veil and curtain which has the secrets of a moral existence behind it,--interest is inspired, curiosity is awakened, and worship is raised. 'surely thou art a god that hidest thyself.' but if god simply hid himself and nothing more, if we knew nothing, we should not wish to know more. but the veil suggests that it _is_ a veil, and that there is something behind it which it conceals." [footnote 1: professor mozley, "university sermons," pp. 145, 146.] now, this is the feeling which the study of astronomy very certainly awakens. every day the astronomer discovers something which quickens his curiosity to discover more. every day he catches new glimpses of the almighty wisdom, which stimulate his desire for a further revelation. and all he learns, and all he anticipates learning, combine to produce in him an emotion of awe. what grandeur lies before him in that endless procession of worlds--in that array of suns and stars extending beyond the limits of the most powerful telescopic vision! how marvellous it is! how beautiful! observe the combination of simplicity with power; note how a great principle of "law" underlies the apparent intricacy of eccentric and intersecting orbits. and then the field of inquiry is inexhaustible. the astronomer has no fear of feeling the satiety of an alexander, when he lamented that he had no more worlds to conquer. what newton said of himself is true of every astronomer,--he is but as a child on the sea-shore, picking up a shell here and a shell there, but unable to grasp a full conception of the mighty ocean that thunders in his ears! and, therefore, because astronomy cherishes the feelings of awe and reverence and praise, because it inspires a continual yearning after additional knowledge, because it reveals to us something of the character of god, we conceive that of all the sciences it affords the purest intellectual gratification. certainly it is one of the most absorbing. its attraction seems to be irresistible. once an astronomer, always an astronomer; the stars, we may fancy, will not relax the spell they lay upon their votary. he willingly withdraws himself from the din and gaiety of social life, to shut himself up in his chamber, and, with the magic tube due to the genius of a galileo, survey with ever-new delight the celestial wonders. so was it with tycho brahé, and copernicus, and kepler; so was it, as the following pages will show, with that remarkable family of astronomers--astronomers for three generations--the herschels. chapter ii. in the quiet city of hanover, nearly a century and a half ago, lived a professor of music, by name isaac herschel, a protestant in religion, though presumably of jewish descent. he had been left an orphan at the early age of eleven, and his friends wished him to adopt the vocation of a landscape-gardener; but being passionately fond of music, and having acquired some skill on the violin, he left dresden, his birthplace, in order to seek his fortune; wandering from place to place, until at hanover, in 1731, he obtained an engagement in the band of the guards. soon afterwards he married; and by his wife, anna ilse moritzen, had ten children, four of whom died in infancy. of the others, two--a brother and a sister--lived to distinguish themselves by their intellectual power; and all true lovers of science will regard with reverence the memories of william and caroline herschel. frederick william herschel was born on the 15th of november 1738. like his father, he displayed an innate musical ability, which was sedulously cultivated and constantly developed; while his general mental training was left to the care of the master of the garrison-school. those who are gifted with a love and a capacity for music sometimes show to little advantage in other pursuits; but such was not the case with william herschel, who progressed so rapidly in all his studies that the pupil soon outstripped the teacher. although, we are told, four years younger than his brother jacob, the two began french together, and william mastered the language in half the time occupied by his senior. his leisure time out of school, when not given up to practice on the oboe and the violin, was devoted to the acquisition, of latin and arithmetic. his father in 1743 was present at the battle of dettingen; and the exposure consequent on a night spent on the rain-soaked battle-field afflicted him with an asthmatic complaint and a partial paralysis of the limbs, which darkened for years the musician's peaceful household. he himself, however, was greatly cheered by the musical proficiency of his two sons, and the intellectual refinement of frederick william. "my brothers," says caroline herschel, "were often introduced as solo performers and assistants in the orchestra of the court; and i remember that i was frequently prevented"--she was then a child about five years old--"from going to sleep by the lively criticism on music on [their] coming from a concert, or conversations on philosophical subjects, which lasted frequently till morning, in which my father was a lively partaker, and assistant of my brother william by contriving self-made instruments." she adds that she often kept herself awake in order to listen to their animating remarks, feeling inexpressibly happy in _their_ happiness,--an indication of that devoted and unselfish affection which afterwards consecrated her whole life. but, generally, their conversation branched out into philosophical subjects; and father and son argued with so much fervour, that the fond mother's interference became necessary,--the immortal names of leibnitz, newton, and euler ringing with a clarion-like peal that boded ill for the repose of the younger members of the family. "but it seems," says caroline, "that on the brothers retiring to their own room, where they shared the same bed, my brother william had still a great deal to say; and frequently it happened that, when he stopped for an assent or a reply, he found his hearer had gone to sleep; and i suppose it was not till then that he bethought himself to do the same. the recollection of these happy scenes confirms me in the belief that, had my brother william not then been interrupted in his philosophical pursuits, we should have had much earlier proofs of his inventive genius. my father," she continues, "was a great admirer of astronomy, and had some knowledge of that science; for i remember him taking me, on a clear frosty night, into the street, to make me acquainted with several of the most beautiful constellations, after we had been gazing at a comet which was then visible. and i well remember with what delight he used to assist my brother william in his various contrivances in the pursuit of his philosophical studies; among which was a neatly-turned four-inch globe, upon which the equator and ecliptic were engraved by my brother." * * * * * in 1755, the tranquil family circle was broken up--the hanoverian regiment in whose band william and jacob were engaged having been ordered to england. the parting was very sorrowful; for the invalid father had derived much support as well as enjoyment from the company of his sons. at first, the english experiences of the young germans were somewhat severe. they endured all the pangs of poverty; pangs endured with heroic composure, while william relaxed not a whit in his devotion to the pursuit of knowledge. happily, however, his musical proficiency attracted the attention of lord durham, who offered him the appointment of bandmaster to a militia regiment stationed in the north of england. in this position he gradually formed a connection among the wealthier families of leeds, pontefract, and doncaster, where he taught music, and conducted the public concerts and oratorios with equal zeal and success. in 1764 he paid a brief but happy visit to his family, much to the joy of his faithful sister, caroline. returning to england, for which country he cherished a strong affection, he resumed his career of patient industry, and in 1765 was appointed organist at halifax. he was now in receipt of an income which secured him due domestic comforts, and enabled him to remedy the defects of his early education. with the help of a grammar and a dictionary he mastered italian. he also studied mathematics and the scientific theory of music, losing no opportunity of adding to his stores of knowledge. in 1766 he obtained the lucrative post of organist to the octagon chapel at bath. increased emoluments, however, brought with them increased obligations. he was required to play almost incessantly, either at the oratorios or in the rooms at the baths, at the theatre, and in the public concerts. when his sister caroline joined him, in 1772, she found him immersed in his various labours. for the choir of the octagon chapel he composed anthems, chants, and complete morning and evening services. a part of every day was occupied in giving lessons to his numerous pupils. in truth, he was one of the busiest men in england; yet in all his arrangements he was so methodical that he found time for everything--and time, more particularly, for the studies in which his soul delighted. his life furnishes an admirable example of what may be accomplished by a man with a firm will and a strong purpose, who sets before himself an end to be attained, and controls all his efforts towards its attainment. he toiled so hard as a musician, because he wanted to be something more. every spare moment of the day, and frequently many hours of the night, he gave up to the pursuits which were gradually leading him into the path best fitted for his genius. the study of mathematics proved but a preliminary to the study of optics; and an accident made him once for all an astronomer. a common two-foot telescope falling into his hands, revealed to him the wonders of the heavens. his imagination was inspired by their contemplation; with ever-increasing enthusiasm he gazed on the revolving planets, on the flashing stars; he determined to fathom more profoundly the constellated depths. a larger instrument was necessary, and herschel wrote to london for it; but the price demanded proved far beyond the resources of the sanguine organist. what should he do? he was not the man to be beaten back by a difficulty: as he could not buy a telescope, he resolved to make one; an instrument eighteen or twenty feet long, which would reveal to him the phases of the remotest planets. and straightway the musician entered on a multitude of ingenious experiments, so as to discover the particular metallic alloys that reflected light with the greatest intensity, the best means of giving the parabolic figure to the mirrors, the necessary degree of polish, and other practical details. in his eager pursuit he enlisted the services of his loving and intelligent sister. "i was much hindered in my musical practice," she writes, "by my help being continually wanted in the execution of the various contrivances; and i had to amuse myself by making the tube of pasteboard for the glasses which were to arrive from london--for at that time no optician had settled at bath. but when all was finished, no one besides my brother could get a glimpse of jupiter or saturn, for the great length of the tube would not allow it to be kept in a straight line. this difficulty, however, was soon removed, by substituting tin tubes." the work went on famously, as might be expected from so much ardour, perseverance, and ingenuity. of a quaker resident at bath, the musician-astronomer purchased a quantity of patterns, tools, hones, polishers, and unfinished mirrors. every room in the house was converted into a workshop. in a handsomely-furnished drawing-room might be seen a cabinetmaker constructing a tube and stands of all descriptions; while herschel's brother alex was engaged in a bedroom in putting up a gigantic turning-machine. meantime, the claims of music could not be ignored: there were frequent rehearsals for the public concerts; lessons to pupils; the composition of glees and catches, and the like; the superintendence of the practice of the chapel choir; and the study of sonatas and concertos for public performance. but all the leisure that could be made or stolen was occupied in labours which proved their own reward. straight from the concert-platform rushed the musician to his workshop, and many a lace ruffle was torn by nails or bespattered by molten pitch; to say nothing of the positive danger to which herschel continually exposed himself by the precipitancy of his movements. for example: one saturday evening, when the two brothers returned from a concert between eleven and twelve o'clock, william amused himself all the way home with the idea of being at liberty to spend the next day, except the few hours' duty at chapel, at the turning-bench; but recollecting that the tools wanted sharpening, they ran with them and a lantern to their landlord's grindstone in a public yard, where, very naturally, they did not wish to be seen on a sunday morning. but william was soon brought back by his brother, almost swooning with the loss of one of his finger-nails. this incident took place in the winter of 1775, at a house situated near walcot turnpike, to which herschel had removed in the summer of the previous year. here, on a grass plot behind the house, he made active preparations for the erection of a twenty-foot telescope. so assiduous was his devotion to this work, that while he was engaged in polishing the mirror, his sister was constantly obliged to feed him by putting his victuals into his mouth. otherwise he would have reduced himself to a condition of positive emaciation! once, when finishing a seven-foot mirror, he did not take his hands from it for sixteen consecutive hours; for in these days machinery had not been devised as a substitute for manual toil. he was seldom unemployed at meals; but at such times employed himself in contriving or making drawings of whatever occurred to his fertile fancy. usually his sister caroline read to him while he was engaged at the turning-lathe, or polishing mirrors; choosing such books as "don quixote," the "arabian nights," the novels of sterne and fielding; and tea and supper were served without any interruption to the task in which herschel was absorbed. in miss herschel's charming letters we find a vivid sketch of the family avocations at this period:-- "my brother applied himself to perfect his mirrors, erecting in his garden a stand for his twenty-foot telescope: many trials were necessary before the required motions for such an unwieldy machine could be contrived. many attempts were made by way of experiment against a mirror before an intended thirty-foot telescope could be completed, for which, between whiles (not interrupting the observations with seven, ten, and twenty-foot, and writing papers for both the royal and bath philosophical societies), gauges, shapes, weights, &c, of the mirror were calculated, and trials of the composition of the metal were made. in short, i saw nothing else and heard nothing else talked of but about these things when my brothers were together. alex was always very alert, assisting when anything new was going forward; but he wanted perseverance, and never liked to confine himself at home for many hours together. and so it happened that my brother william was obliged to make trial of my abilities in copying for him catalogues, tables, &c, and sometimes whole papers which were lent [to] him for his perusal. among them was one by mr. michel, and a catalogue of christian mayer in latin, which kept me employed when my brother was at the telescope at night. when i found that a hand was sometimes wanted when any particular measures were to be made with the lamp micrometer, or a fire to be kept up, or a dish of coffee necessary during a night's long watching, i undertook with pleasure what others might have thought a hardship." the astronomer-musician's patient survey of the heavens was rewarded, on the 13th of march 1781, by the discovery of a new planet, situated on the borders of our solar system. in every way this was a discovery of signal importance. it broke up the traditional conservatism of astronomers, which had almost refused to regard as possible the existence of any planets beyond the orbit of saturn, because for so many years none had revealed themselves to the watchful gaze. men's minds were widened, so to speak, at a bound; their conceptions strengthened and enlarged; for the discovery of georgium sidus--as the new planet was designated by its discoverer, in honour of george iii.--rendered possible and probable the discovery of other planets, and thus extended immeasurably the limits of the solar system. herschel, whose reputation as a musician had hitherto been local, now sprang into world-wide fame as an astronomer. george iii., who was a true lover of science, and not disinclined to bestow his patronage on men and things of hanoverian origin, summoned him to his presence; and was so much pleased with his modest and interesting account of the long labours which had led to the great result, that, after a brief interval, he bestowed upon him an annual pension of three hundred guineas, and a residence, first at clay hall, and then at slough. but before this well-deserved good fortune fell to him, herschel continued his industrious career as both musician and astronomer. during the concert season, which lasted five or six months, he had never a night disengaged, but was conducting oratorios at bath or bristol, arranging for public concerts, attending rehearsals, and superintending the performances of his choir. as soon as a lull came, the indomitable man, assisted by his faithful sister, returned to his astronomical pursuits. to gain a fuller and clearer knowledge of the starry worlds scattered over the vast fields of space, herschel from the first had seen that instruments of much greater power were necessary than any hitherto used by astronomers. he set to work, therefore, on the construction of a thirty-foot telescope; the metallic mirror of which must, of course, be of proportionate dimensions. this huge mirror was to be cast in a mould of loam prepared from horse-dung, of which an immense quantity was to be pounded in a mortar, and sifted through a fine sieve; an arduous and almost endless task, undertaken by caroline herschel and her brother alex. then a furnace was erected in a back-room on the ground-floor; and every preparation having been made, a day was set apart for the casting. the day came, and herschel and his collaborateurs looked forward to the consummation of their hopes. the metal was placed in the furnace; but, unfortunately, just when it was ready for pouring in a molten stream into the mould, it began to leak, and both the herschels, and the caster with his men, were compelled to fly from the apartment, the stone flooring exploding, and flying about in all directions, as high as the ceiling. the astronomer, exhausted with heat and exertion, fell on a heap of brickbats; exhausted, but not dismayed. the work was renewed; and a second casting being attempted, it proved entirely successful, and a very perfect metal was formed in the mould. chapter iii. in august 1782 the herschels removed to datchet. their new home was "a large neglected place; the house in a deplorably ruinous condition, the garden and grounds overgrown with weeds." nor were the domestic arrangements more favourable. for a fortnight the little family were without a female servant; and an old woman, the gardener's wife, showed miss herschel the shops, where the high prices of every article, from coals to butcher's meat, appalled her. but of these inconveniences herschel took no account. enough for him that he was released from the drudgery of teaching, and free thenceforth to devote himself to the heavens and their wonders. a man whose thoughts are always with the stars can hardly be expected to trouble himself about the price of tallow-candles! were there not capacious stables in which mirrors of any size could be ground; and a roomy laundry capable of easy conversion into a library, with one door opening on a large lawn, where the "small twenty-foot" was to take its stand? compared with advantages such as these, what mattered the scarcity of "butcher's meat"? herschel laughingly assured his sister that they could live on eggs and bacon; which, he confidently asserted, would cost next to nothing, now that they were really in the country! and so he settled down to a life of quiet, industry at datchet; his admirable sister being formally adopted as his assistant and secretary. never had master a more devoted, a more enthusiastic, or a more intelligent servant! she shared in all his night-watches, with her eye constantly on the clock, and the pencil in her hand; with unerring accuracy she made all the complex calculations so frequently required; she made three or four copies of every observation in separate registers, co-ordinating, classifying, and analyzing them. if the scientific world, says arago, saw with astonishment the unexampled rapidity with which herschel's works succeeded one another for many years, they were greatly indebted for this affluence of production to the affectionate ardour of his sister caroline. her enthusiasm never failed; her industry knew no check; and her brother's fame was dearer to her than life. in one of her letters she describes with graphic simplicity the "interior" at datchet:- "i found that i was to be trained for an assistant-astronomer; and by way of encouragement, a telescope adapted for 'sweeping' (or rapidly surveying a wide extent of space), consisting of a tube with two glasses, was given [to] me. i was to 'sweep for comets;' and i see by my journal that i began august 22nd, 1782, to write down and describe all remarkable appearances i saw in my 'sweeps.' but it was not till the last two months of the same year that i felt the least encouragement to spend the starlit nights on a grass-plot covered with dew or hoar-frost, without a human being near enough to be within call. i knew too little of the real heavens to be able to point out every object so as to find it again without losing too much time by consulting the atlas. but all these troubles were removed when i knew my brother to be at no great distance, making observations with his various instruments on double stars, planets, and the like; and i could have his assistance immediately when i found a nebula, or cluster of stars, of which i intended to give a catalogue. i had the comfort to see," she continues, "that my brother was satisfied with my endeavours to assist him when he wanted another person either to run to the clocks, write down a memorandum, fetch and carry instruments, or measure the ground with poles,--of which something of the kind every moment would occur." the conscientious care and assiduous industry with which herschel made his measurements of the diameter of the georgium sidus (now called uranus), and his interesting observations of other planets, of double stars with their coloured light, of cometary and nebulous appearances, were truly remarkable; as may be seen by the various papers which he wrote at this time for the royal society. in addition to all this labour, he perfected a twelve-inch speculum of vast magnifying power before the spring of 1784; and many hours were spent at the turning-bench, as not a night clear enough for observing ever passed without the devising of improvements in the mounting and motion of the various instruments then in use, or the test and trial of newly-constructed "eyepieces," most of which were executed by herschel's own hands. "wishing to save his time, he began to have some work of that kind done by a watchmaker, who had retired from business, and lived on datchet common; but the work was so bad, and the charges [were] so unreasonable, that he could not be employed. it was not till some time afterwards, in his frequent visits to the meetings of the royal society (made in moonlight nights), that he had an opportunity of looking about for mathematical workmen, opticians, and founders. but the work seldom answered expectation, and it was kept to be executed with improvements by alexander during the few months he spent with us." * * * * * in july 1783 herschel began his observations with his large twenty-foot telescope, though it was in an unfinished state; and his sister watched and waited with much apprehension when she knew him to be elevated some fifteen feet or more on a temporary crossbeam instead of a safe gallery. here it is needful to explain, perhaps, that these huge astronomical telescopes are not used like ordinary glasses, to one end of which the observer applies his eye; the objects towards which the tube is directed being thrown upon a large mirror, which is attached to it externally at some distance from the ground. the observer, therefore, needs to be mounted on an elevated platform or gallery, from which he can conveniently inspect the mirror. one night, in a very high wind, herschel had scarcely descended from his station before the whole apparatus came down; and his sister was in continual apprehension of some serious accident. one such, indeed, occurred, and to herself. the evening of the 31st of december had been cloudy, but as a few stars shone forth about ten o'clock, hurried preparations were made for observing. herschel, standing at the front of the telescope, directed his sister to make a certain alteration in the lateral motion, which was done by machinery, on which the point of support of the tube and mirror rested. at each end of the machine or trough was an iron hook, such as butchers use for suspending their joints of meat; and having to run in the dark across ground covered a foot deep with melting snow, miss herschel fell on one of these hooks, which entered her right leg above the knee. to her brother's injunction, "make haste!" she could answer only by a pitiful cry, "i am hooked!" he and the workmen hastened immediately to her assistance, but they could not disentangle her without leaving nearly two ounces of her flesh behind. for some weeks she was an invalid, and at one time it was feared that amputation might be necessary. * * * * * not satisfied with the magnifying power of any of the instruments he had hitherto constructed, herschel resolved, in 1784, to attempt a forty-foot telescope. such a work, however, was far beyond his limited private resources; and he did not venture to undertake it until promised a royal bounty of £2000. then he removed from datchet to clay hall, old windsor; and again, in 1786, to slough, where he finally settled, and succeeded in erecting a commodious and well-equipped observatory. "we may confidently assert," says arago, "relative to the little house and garden of slough, that it is the spot of all the world where the greatest number of discoveries have been made. the name of that village will never perish: science will transmit it religiously to our latest posterity." at slough, as at datchet, prevailed the most enthusiastic industry; and the house was soon as full of well-ordered labour as a bee-hive. smiths were kept constantly at work on different parts of the new telescopic leviathan; and a whole troop of labourers was engaged in grinding the tools required for shaping and polishing its mirror. had not a cloudy or moonlight night sometimes intervened, herschel and his sister must have died of sheer exhaustion, for they toiled with unremitting ardour both day and night. with the morning came the workpeople, of whom no fewer than between thirty and forty were at work for upwards of three months together: some employed in felling and rooting out trees, some digging and preparing the ground for the bricklayers, who were laying the foundation for the telescope. then there were the carpenter and his men; and, meanwhile, the smith was converting a wash-house into a forge, and manufacturing complete sets of tools for his own share of the labour. in short, the place was at one time a complete workshop for the manufacture of optical instruments; and it was a pleasure to enter it for the purpose of observing the fervour of the great astronomer, and the reverent attention given to his orders. it is impossible not to refer here to the sisterly devotion of caroline herschel, who was in every respect worthy of her noble-minded, tender-hearted, and enthusiastic brother. she stood beside him to the last, sharing his labours, brightening his life. in the days, says her biographer, when herschel gave up a lucrative career that he might dedicate all his energies to astronomical pursuits, it was through her care and thriftiness that he was spared from the unrest of pecuniary anxieties. as she had been his helper and assistant during his career as a popular musician, so she became his helper and assistant when he gave himself up, like the chaldeans of old, to the study of the stars. by dint of a resolute will and a love that shrank from no sacrifice or exertion, she acquired such a knowledge of mathematics and calculations, mysterious as these generally seem to the feminine mind, that she was able to formulate with exactness the result of her brother's researches. she never failed to be his willing fellow-labourer in the workshop; she helped him to grind and polish his mirrors; she stood beside his telescope, in order to record his observations, during the dark and bitter mid-winter nights, when the very ink was frozen in the bottle. it may be said, without exaggeration, that she kept him alive by her care: thinking nothing of herself, she lived for him, and him alone. she loved him, she believed in him, she aided him with all her heart and all her strength. her mental powers were very considerable; and undoubtedly she might have attained to eminence on her own account, for she herself discovered no fewer than eight comets. but she shunned self-glorification; she desired to live in her brother's shadow; she worked for him, never for herself; and in her elevated character no feature more strongly demands our admiration than her heroic though unconscious self-denial. happy the man who has such a sister; happy the sister whose brother is worthy of so much devotion! it is pleasant to know that william herschel deserved the love so lavishly poured out at his feet; that great as were his achievements in science, lofty and broad as was his genius, they were fully sustained and ennobled by the beauty and worth of his inner life. who can contemplate their twofold career in all its singleness of purpose, its purity, its unselfishness, its sublime disregard of worldly pleasures, without emotion? the lessons told by such a life are worth all the moral treatises ever written. to miss herschel's diary we again refer, for a glimpse of the occupations of her brother and herself at slough in the first two years of their residence. these two years, to use an apt expression of her own, were spent in a perfect chaos of business. the garden and workrooms swarmed with labourers and workmen--smiths and carpenters speeding to and fro between the forge and the forty-foot machinery; and so incessant was the vigilance of herschel, that not a screw-bolt in the whole apparatus was fixed except under his eye. "i have seen him," writes his sister, "lying stretched many an hour in the burning sun, across the top beam, whilst the iron-work for the various motions [of the great telescope] was being fixed." at one time no fewer than twenty-four men, in relays of twelve each, were engaged in grinding and polishing day and night; and herschel never left them, taking his food without allowing himself time to sit down to table. "in august 1787," writes the diarist, "an additional man-servant was engaged, who would be wanted at the handles of the motions of the forty-foot,"--that is, to raise or lower it, or move it from side to side, as might be required,--"for which the mirror in the beginning of july was so far finished as to be used for occasional observations on trial. such a person was also necessary for showing the telescopes to the curious strangers, as by their numerous visits my brother and myself had for some time past been much incommoded. in consequence of an application made through sir j. banks to the king, my brother had in august a second sum of £2000 granted for completing the forty-foot, and £200 yearly for the expense of repairs; such as ropes, painting, &c., and the keep and clothing of the men who attended at night. a salary of £50 a year was also settled on me, as an assistant to my brother. a great uneasiness was by this means removed from my mind; for though i had generally (and especially during the last busy six years) been almost the keeper of my brother's purse, with a charge to provide for my personal wants, only annexing in my accounts the memorandum '_for car_.' to the sums so laid out. when cast up, they hardly amounted to seven or eight pounds per year since the time we had left bath. nothing but bankruptcy had all the while been running through my silly head, when looking at the sums of my weekly accounts, and knowing they could be but trifling in comparison with what had been and had yet to be paid in town. i will only add, that from this time the utmost activity prevailed to forward the completion of the forty-foot." in recognition of his scientific triumphs, the honorary degree of ll.d was conferred upon herschel, in 1786, by the university of oxford. they were triumphs that well merited such a recognition. he had already made some important observations on the nature of double stars, on the dimensions of the telescopic planets, and had begun his famous investigations into the composition of the nebulae,--those clusters of stars and nebulous matter which had previously proved such a problem to astronomers. the remarkable phenomenon of a periodical change of intensity in certain stars, which wax and wane in radiance like a revolving light, had also excited his attention. further, he had entered upon the experiments which ultimately showed that the sun positively moves; that in this, as in other respects, the magnificent orb of day must be ranged among the stars; that the apparently inextricable irregularities of numerous sidereal proper motions arise in great part from the displacement of the solar system; that, in short, the point of space toward which earth and its sister planets are annually advancing, is situated in the constellation of hercules. "let us," says a french writer, "to these immortal labours add the ingenious ideas that we owe to herschel on the nebulae, on the constitution of the milky way, on the universe as a whole,--ideas which almost by themselves constitute the actual history of the formation of the worlds,--and we cannot but have a deep reverence for that powerful genius that scarcely ever erred, notwithstanding the ardour of its imagination." the ordinary spectator, looking upon the face of the heavens through a telescope, had, prior to herschel's time, felt his curiosity excited by the appearance here and there of filmy patches, vague in structure and irregular in shape, which, from their resemblance to clouds, received the name of _nebulae_. what these were, no astronomer had succeeded in defining. it was left for herschel, with his rare powers of patient and discriminating observation, assisted by the more powerful instruments which his ingenuity succeeded in constructing, to discern in them innumerable groups of worlds, in various stages of formation! a new light was thrown upon the history of the universe. man was able to assist, as it were, at the process of creation, and to watch the development of a mass of incoherent matter into a perfect star. this alone was a discovery which might well have immortalised the name of herschel. but we owe to him the elements of our knowledge of the sun's physical constitution. he swept aside the erroneous theories and conjectures which had previously prevailed, and guided the astronomical inquirer into the right path. he convinced himself, by long and patient researches, that the luminous envelope of the great "orb of day" was neither a liquid nor an elastic fluid; that it was in certain respects analogous to the clouds which wreathe our mountain-summits and fertilize our plains; that it floated in the solar atmosphere. thence he came to the conclusion that the sun has two atmospheres, endowed with motions quite independent of each other. an elastic fluid, now known as the _photosphere_, is in course of continual formation on the dark rugged surface of the solar mass; and rising, on account of its specific lightness, it forms the _pores_ in the stratum of reflecting clouds; then, combining with other gases, it produces the irregularities or furrows in the luminous cloud-region. when the ascending currents are powerful, they create those appearances which astronomers designate the _nuclei_, the _penumbrae_, the _faculae_. such was herschel's explanation of the mode of formation of the solar spots; and allowing it to be well-founded, we must expect to find--what is, indeed, the case--that the sun does not always and regularly pour forth equal quantities of light and heat. it is true that herschel's hypothesis has been modified by later astronomers; but his is the credit of having directed them into the right course of inquiry and observation. * * * * * the physical constitution of the moon was a subject which also engaged the attention of our indefatigable enthusiast. as early as 1780 he attempted the measurement of the lunar mountains, and came to the conclusion that few of them exceeded 2600 feet in height. later research, however, has proved these figures to be inadequate. next he addressed himself to a study of the lunar volcanoes, three of which he declared to be in a state of ignition; two of them apparently on the decline, the third still active. he was so convinced of the reality of the phenomenon, that on the 20th of april 1787 he wrote:--"the volcano burns with greater violence than it did last night." the real diameter of the volcanic light he estimated at 16,400 feet. its intensity he described as superior to that of the nucleus of a comet then flashing across our system. the objects situated near the crater were fully illuminated by the glare of its burning matter. it may seem strange that, after observations so exact and minute, few astronomers now admit the existence of active volcanoes in the moon. the reasons for their incredulity are thus stated:-the various parts of the moon do not all reflect with the same intensity. here, that intensity may be dependent on the form; elsewhere, on the nature of the materials. those persons who have examined the lunar orb with telescopes, know how very considerable the difference arising from these two causes may be,--with how much keener and stronger a radiance one point of the moon will sometimes shine than those around it. well, it would seem to be obvious that the ratio of intensity between the brilliant parts and the faint parts must always be the same, whatever the origin of the illuminating light. in that portion of the lunar sphere which receives the glow and glory of the sun, we know that some points exist, the brightness of which is extraordinary compared with the feeble flickering gleam of those around them. and these same points, when seen in the dim reflection of the earth, will still predominate in intensity over the neighbouring regions. in this way arago and others explain the observations of herschel, without admitting the existence of active volcanoes in the moon. that volcanoes there are, is a familiar fact; but they would seem to have exhausted their activity in long-past ages. the lunar surface is now a dreary waste of rugged lava and ashes, covered with the matter ejected from craters once in a state of furious eruption. the moon, in fact, is a world which has burned itself out. how strange the thought that in a far-back period the inhabitants of earth, had earth then been inhabited, might have seen the glare of countless volcanoes diffused, lurid and threatening, over the face of their satellite! how strange the thought that the once active fires should all have died away, and the moon have thus been prepared for the better reception and reflection of the solar radiance in order to illuminate the nights of earth! the planets, needless to say, were the objects of herschel's assiduous attention. mercury was the one which least interested him; but he ascertained the perfect circularity of its disc. with respect to venus, he endeavoured to determine the time of its rotation from 1777. we owe to him the discovery of the true shape of the "red planet mars,"--that, like the earth, it is an oblate spheroid, or flattened at the poles. after piazzi, olbers, and harding had discovered the small planets, ceres, pallas, juno, and vesta, he applied himself to the measurement of their angular diameters. his researches led him to the conclusion that these four new bodies could not properly be ranked with the planets, and he proposed to call them asteroids--a name now generally adopted. since herschel's time, the number of these minor planets known to astronomers has increased to upwards of one hundred. with respect to jupiter, our astronomer arrived at some important facts in connection with the duration of its rotation. he also made numerous observations on the intensities and comparative magnitudes of its satellites. we come next in order to saturn, the gloomy planet which the ancient astrologers regarded with so much dislike. here, too, we find traces of herschel's labours. not only has he enlarged our knowledge of its equatorial compression, of its physical constitution, and of the rotation of its luminous belt or ring, but he added two to the number of its satellites. five only of these were known at the close of the seventeenth century; of which cussiric discovered four, and huygens one. it was universally believed that the subject was exhausted. but, on the 28th of august 1780, herschel's colossal tube revealed to his delighted gaze a satellite nearer to the saturnian ring than those previously observed. and a few days later, on the 17th of september, a seventh and last satellite crossed his field of vision. it was situated between the former and the ring; that is, it is the nearest to it of the seven. but the most remarkable of herschel's achievements was the discovery of the planet uranus, and the detection of its satellites. on the 13th of march 1781, between ten and eleven o'clock at night, the great astronomer was engaged in examining the small stars near h in the constellation gemini, with a seven-foot telescope, bearing a magnifying power of two hundred and twenty-seven times. it appeared to him that one of these stars was of an unusual diameter; and he came to the conclusion, therefore, that it was a comet. it was under this denomination that it was discussed at the meeting of the royal society. but the researches of herschel at a later period showed that the orbit of the new body was circular, and accordingly it was elevated to the rank of a planet. as already stated, herschel named it, in compliment to george iii., the georgium sidus; in this copying the example of galileo with his "medicaean stars." afterwards, astronomers christened it herschel, and subsequently uranus, in conformity with the mythological nomenclature of the other planets. the immense distance of uranus from our earth, its small angular diameter, and the feebleness of its light, seemed to preclude the hope that, if it were attended by satellites of the same dimensions in proportion to its own magnitude as those of the satellites of jupiter and saturn in proportion to _their_ magnitude, they could be descried by any human observer. the patient, persevering, reverent temper of herschel took no account, however, of any discouraging or unpropitious circumstances. what he did was to substitute for telescopes of the ordinary construction the new and gigantic forty-foot tube already described; and, thus, with unremitting vigilance and intense zeal, he arrived at the discovery (between january 4, 1787, and february 28, 1794) of the _six_ satellites of uranus; in other words, he revealed to man the completeness of a new system,--a system which will always be identified with his name. * * * * * those singular meteors, the comets, which flash through heaven with long trails of light, and of old astonished the nations as if they were harbingers of some overwhelming calamity, were also the frequent subjects of our astronomer's investigations. he brought some of his fine and powerful instruments to bear on a comet discovered by mr. pigott in 1807, and closely and carefully investigated its physical constitution. the nucleus, or head, was circular and well determined, and evidently shone by its own light. very small stars seemed to grow pale, "to hide their diminished heads," when seen through its _coma_ or tail. it is true, however, that this faintness may have been only apparent, and due to the circumstance of the stars being projected on a luminous background. such was herschel's explanation. a gaseous medium, capable of absorbing sufficient solar radiance to efface the light of some "lesser stars," appeared to him to possess in each stratum a sensible quantity of matter. hence it would cause a real diminution of the light transmitted, though nothing would indicate the existence of such a cause.[1] [footnote 1: this conclusion is disputed by many astronomers.] herschel examined the beautiful comet of 1811 with equal accuracy. "large telescopes showed him, in the midst of the gaseous head, a rather reddish body of planetary appearance, which bore strong magnifying powers, and showed no sign of _phase_ (that is, of change of aspect, as in the case of the moon). hence herschel concluded that it was self-luminous. yet, if we reflect that the planetary body under consideration was not a second in diameter, the absence of a phase," says arago, "does not appear a demonstrative argument." the same writer adds:- "the light of the head had a bluish-green tint." was this a real tint, or did the central reddish body, only through contrast, make the surrounding vapour appear to be coloured? herschel did not examine the question from this point of view. "the head of the comet appeared to be enveloped at a certain distance, on the side towards the sun, by a brilliant narrow zone, embracing about a semicircle, and of a yellowish colour. from the two extremities of the semicircle arose, towards the region away from the sun, two long luminous streaks which limited the tail. between the brilliant circular semi-ring and the head, the cometary substance appeared to be dark, of great rarity, and very diaphanous. "the luminous self-ring floated: one day it seemed to be suspended in the diaphanous atmosphere by which the head of the comet was surrounded, at a distance of 322,000 english miles from the nucleus. "this distance was not constant. the matter of the semi-annular envelope seemed even to be precipitated by slow degrees through the diaphanous atmosphere; finally, it reached the nucleus; the earlier appearances vanished; the comet was reduced to a globular nebula. "during its period of dissolution, the ring appeared sometimes to have several branches. "the luminous shreds of the tail apparently underwent rapid, frequent, and considerable variations of length. herschel discerned symptoms of a rotatory movement both in the comet and its tail; a movement which carried unequal shreds from the centre towards the border, and the border towards the centre. on examining at intervals the same region of the tail--the border, for example--sensible changes of length must have been perceptible; which, however, had no reality in them. herschel thought that both the comet of 1811 and that of 1807 were self-luminous. the second comet of 1811 appeared to him to shine only by borrowed light. it must be acknowledged that these conjectures did not rest on anything demonstrative. "in attentively comparing the comet of 1807 with the beautiful comet of 1811, relative to the changes of distance from the sun, and the modifications resulting thence, herschel put it beyond doubt that these modifications have something individual in them,--something relative to a special state of the nebulous matter. on one celestial body the changes of distance produce an enormous effect, on another the modifications are insignificant." we have reproduced these observations by a distinguished french astronomer, in order to show the reader what was the nature, and how great was the importance, of herschel's labours, and in how remarkable and comprehensive a manner he conducted his survey of the celestial phenomena. we now return to our brief narrative of his life. such a life, absorbed in tranquil and incessant studies, presents no curious, romantic, or surprising incidents. it was the life of a reverent, patient, gentle, and devoted man of genius, who dedicated himself to the task of making known the "wondrous works of god" to his fellow-men, and who in all his social and domestic relations was without blot or stain. in 1788 he married the widow of john pitt, esq., with whom he received a considerable fortune, and thus for the remainder of his life he was enabled to give himself up to his favourite pursuits unembarrassed by pecuniary anxieties. his marriage was in every respect a happy one, and effectually secured his domestic peace. by his wife he had an only son,--the late sir john herschel,--who worthily maintained the scientific dignity of his name. it is said, by the highest of all authority, that a prophet is not honoured in his own country. but our astronomer was not without the reward of his work, even in his lifetime. the university of oxford conferred upon him the illustrious honorary degree of d.c.l. in 1816 he received the guelphic order of knighthood; and in 1820 he was chosen the first president of the astronomical society. from his sister's diary we gather a few particulars illustrative of his mode of life. on the 4th of october 1806 she writes:- "my brother came from brighton. the same night two parties from the castle [windsor] came to see the comet, and during the whole month my brother had not an evening to himself. as he was then in the midst of polishing the forty-foot mirror, rest became absolutely necessary after a day spent in that most laborious work; and it has ever been my opinion, that on the 14th of october his nerves received a shock of which he never got the better afterwards; for on that day (in particular) he had hardly dismissed his troop of men, when visitors assembled, and from the time it was dark till past midnight he was on the grass-plot, surrounded by between fifty and sixty persons, without having had time for putting on proper clothing, or for the least nourishment passing his lips. "_february 6th, 1807_.--when i came to slough to assist my brother in polishing the forty-foot mirror, i found my nephew[1] very ill with an inflammatory sore throat and fever. "_february 9th_.--still very ill; and my brother obliged to go on with the polishing of the great mirror, as every arrangement had been made for that purpose.--_mem_. i believe my brother had reasons for choosing the cold season for this laborious work, the exertion of which alone must put any man into a fever, if he were ever so strong. "_february 10th_.--from this day my nephew's health kept on mending. "_february 19th_.--my nephew mending, but my brother not well. "_february 26th_.--my brother so ill that i was not allowed to see him, and till march 8th his life was despaired of; and by march 10th i was permitted to see him, but only for two or three minutes, as he was not allowed to speak. "_march 22nd_.--he (sir william) went for the first time into his library, but could only remain for a few moments." [footnote 1: afterwards sir john herschel.] from this dangerous attack sir william recovered, but thenceforth it was clear to his friends that his strength gradually decreased, though not his enthusiasm or his industry. he persevered in his life-long labours with all his old intellectual force. what failed him was neither his tender affections nor his mental powers; but his body refused to answer all the demands made upon it by the resolute will,--the sword was slowly but surely wearing out the scabbard. under the date of april 2, 1819, we meet with an ominous entry in his loving and faithful sister's diary:- "my brother left slough, accompanied by lady herschel, for bath, he being very unwell; and the constant complaint of giddiness in the head so much increased, that they were obliged to be four nights on the road both going and coming. the last moments before he stepped into the carriage were spent in walking with me through his library and workrooms, pointing with anxious looks to every shelf and drawer, desiring me to examine all, and to make memorandums of them as well as i could. he was hardly able to support himself; and his spirits were so low, that i found difficulty in commanding my voice so far as to give him the assurance he should find on his return that my time had not been misspent. "when i was left alone, i found that i had no easy task to perform, for there were packets of writings to be examined which had not been looked at for the last forty years. but i did not pass a single day without working in the library as long as i could read a letter without candlelight, and taking with me papers to copy, which employed me for best part of the night; and thus i was enabled to give my brother a clear account of what had been done at his return. but (may 1) he returned home much worse than he went, and for several days hardly noticed my handiwork." to this same year of decay and decline (1819) belongs a small slip of yellow paper, inscribed with the following lines in a tremulous and feeble handwriting, which is jealously preserved by the illustrious astronomer's descendants:- "lina,--there is a great comet. i want you to assist me. come to dine, and spend the day here. if you can come soon after one o'clock, we shall have time to prepare maps and telescopes. i saw its situation last night,--it has a long tail. "_july 4, 1819_." then follows:- "i keep this as a relic! every line _now_ traced by the hand of my dear brother becomes a treasure to me. "c. herschel." we know of nothing more touching in literary history than this noble, self-sacrificing, generous affection of the sister towards her eminent brother. such instances of absolute self-denial and all-absorbing love elevate our opinion of human nature generally, and prove that something of the divine image lingers in it still. herschel was now bordering upon the ripe old age of eighty, and it is no wonder that, after a life of incessant study, his strength should daily diminish. in 1822 it became painfully evident to his attached relatives and friends that the end was not far off; and on the 25th of august he passed away to his rest. we owe an account of his last days to his sister, but for whose pious care, indeed, very little of his private life would have been known, and herschel could have been judged only from the recorded results of his immense labours. "_may 20th_.--the summer proved very hot; my brother's feeble nerves were very much affected, and there being in general much company, added to the difficulty of choosing the most airy rooms for his retirement. "_july 8th_.--i had a dawn of hope that my brother might regain once more a little strength, for i have a memorandum in my almanac of his walking with a firmer step than usual above three or four times the distance from the dwelling-house to the library, in order to gather and eat raspberries, in his garden, with me. but i never saw the like again. "the latter end of july i was seized by a bilious fever, and i could for several days only rise for a few hours to go to my brother about the time he was used to see me. but one day i was entirely confined to my bed, which alarmed lady herschel and the family _on my brother's account_. miss baldwin [a niece of lady herschel] called and found me in despair about my own confused affairs, which i never had had time to bring into any order. the next day she brought my nephew to me, who promised to fulfil all my wishes which i should have expressed on paper; he begged me not to exert myself, for his father's sake, of whom he believed _it would be the immediate death if anything should happen to me_." afterwards she wrote:- "of my dear nephew's advice i could not avail myself, for i knew that at that time he had weighty concerns on his mind. and, besides, my whole life almost has passed away in the delusion that, next to my eldest brother, none but dietrich was capable of giving me advice where to leave my few relics, consisting of a few books and my sweeper [that is, the seven-foot telescope with which she was accustomed to sweep the heavens for comets]. and for the last twenty years i kept to the resolution of never opening my lips to my dear brother william about worldly concerns, let me be ever so much at a loss for knowing right from wrong." miss herschel proceeds to note that on the afternoons of the 11th, 12th, 13th, and 14th of august, she, "as usual," spent some hours with her brother. on the 15th she hastened to the accustomed place, where she generally found him, with the newspaper which she was to read aloud for his amusement. but, instead, she found assembled there several of his nearest friends, who informed her that her aged brother had been compelled to return to his room. she lost no time in seeking him. he was attended by lady herschel and his housekeeper, who were administering everything which was likely to keep up his failing strength. miss herschel observed that he was much irritated, with the irritation natural to old age and extreme bodily feebleness, at his inability to grant a friend's request for some token of remembrance for his father. no sooner did he see miss herschel, the loving companion and fellow-worker of so many years, than he characteristically employed her to fetch one of his last papers, and a plate (or map) of the forty-foot telescope. "but, for the universe," says miss herschel, "i could not have looked twice at what i had snatched from the shelf; and when he faintly asked if the breaking up of the milky way[1] was in it, i said, 'yes,' and he looked content." i cannot help remembering this circumstance; it was the last time i was sent to the library on such an occasion. that the anxious care for his papers and workrooms never ended but with his life, was proved by his frequent whispered inquiries if they were locked and the key safe; of which i took care to assure him that they were, and the key in lady herschel's hands. [footnote 1: the _via lactea_, or "milky way," had long been supposed to consist of a nebulous, vague, luminous matter, but herschel showed that it was really made up of stars and systems of stars.] after struggling for some thirty minutes against his rapidly increasing weakness, the great astronomer, bowed by his burden of years and labours, was forced to retire to his bed, with little hope that he would ever rise from it again. for ten days and nights his wife and sister watched by his side in painful suspense, until, on the 25th of august, the end came. peacefully closed a life which had passed in a peace and quietness not often vouchsafed to man. * * * * * herschel, says a brother astronomer, will never cease to occupy an eminent place in the small group of our contemporary men of genius, while his name will descend to the most distant posterity. the variety and the magnificence of his labours vie with their extent. the more they are studied, the more they are admired. for it is with great men as it is with great movements in the arts and in national history,--we cannot understand them without observing them from different points of view. what a brilliant roll of achievements is recalled to the mind by the name of william herschel! the discovery of uranus, and of its satellites; of the fifth and sixth satellites of saturn; of the many spots at the poles of mars; of the rotation of saturn's ring; of the belts of saturn; of the rotation of jupiter's satellites; of the daily period of saturn and venus; and of the motions of binary sidereal systems,--added to his investigations into nebulae, the milky way, and double, triple, and multiple stars;--all this we owe to his patient, his persevering, his daring genius! he may almost be styled the father of modern astronomy. chapter iv. we now propose to furnish a brief sketch of the life of sir john frederick william herschel, the only son of sir william, and not less illustrious as a man of science. he was born at slough, in the year 1792. evincing considerable talents at a very early age, he received a careful private education under mr. rogers, a scottish mathematician of distinguished merit; and afterwards was sent to st. john's college, cambridge, always famous as a nursery of mathematical and scientific prodigies! here he pursued his studies with remarkable success, suffering no obstacles to daunt him, and wasting no opportunities of improvement. his fellow-collegians regarded him as one who would add to the high repute of the college, and rejoiced at the brilliant ease with which he passed every examination. in 1813 he took his degree of b.a., and consummated a long series of successes by becoming "senior wrangler," and "smith's prizeman;" these being the two highest distinctions to which a cambridge scholar can attain. in the same year, when he was hardly twenty-one, he published a work entitled, "a collection of examples of the application of the calculus to finite differences." to our young readers such a title will convey no meaning; and we refer to it here only to illustrate the industry and careful thought of the young student, which had rendered possible such a result. returning to slough, he continued his studies in mathematics, chemistry, and natural philosophy, and in various publications exhibited that faculty of observation and analyzation, that intelligence and scrupulousness in collecting facts, and that boldness in deducing new inferences from them, which were characteristic of his illustrious father. the subjects he took up were so abstruse, that we could not hope to make our readers understand what he accomplished, or how far he excelled his predecessors in his grasp and comprehension of them. for instance: if we tell them that in 1820 he wrote a paper "on the theory and summation of series;" communicated to the cambridge philosophical society his discovery that the two kinds of rotatory polarization in rock crystal were related to the plagihedral faces of that mineral; and issued an able treatise "on certain remarkable instances of deviation from newton's tints in the polarized tints of uniaxal crystals,"--they will gain no very distinct idea of the significance or value of these researches. again: it will not be very intelligible to them to be informed that, in 1822, he communicated to the royal society of edinburgh a paper "on the absorption of light by coloured media", in which he enunciated a new method of measuring the dispersion of transparent bodies by stopping the green, yellow, and most refrangible red rays, and thus rendering visible the rays situated rigorously at the end of the spectrum. but they will understand that these results could have been attained only by the most assiduous industry and the most unflinching perseverance. and it is on account of this industry and this perseverance that we recommend herschel as an example to our readers. they may not make the same progress in science, or achieve the same reputation. it is not necessary they should. humble work is not less honourable, if it be done conscientiously, and with a sincere desire to do the best that it is in our power to do. an interesting feature in the younger herschel's character was his loving care for his father's fame. he was ever most anxious that the full measure of his services to science should be recognized and appreciated. thus, in 1823, he writes to his aunt:- "i have been long threatening to send you a long letter, but have always been prevented by circumstances and want of leisure from executing my intention. the truth is, i have been so much occupied with astronomy of late, that i have had little time for anything else--the reduction of those double stars, and the necessity it has put me under of looking over the journals, reviews, &c, for information on what has already been done, and in many cases of re-casting up my father's measures, swallows up a great deal of time and labour. but i have the satisfaction of being able to state that our results in most instances confirm and establish my father's views in a remarkable manner. these inquiries have taken me off the republication of his printed papers for the present. "i think i shall be adding more to his fame by pursuing and verifying his observations than by reprinting them. but i have by no means abandoned the idea. meanwhile, i am not sorry to hear they are about to be translated into german.... i hope this season to commence a series of observations with the twenty-foot reflector, which is now in fine order. the forty-foot is no longer capable of being used, but i shall suffer it to stand as a monument." * * * * * in reference to this famous telescope, we may digress to state that its remains have been carefully preserved. the metal tube of the instrument, carrying at one end the recently cleaned mirror of four feet ten inches in diameter, has been placed horizontally in the meridian line, on solid piles of masonry, in the midst of the circle where the apparatus used in manoeuvring it was formerly placed. on the 1st of january 1840, sir john herschel, his wife, their seven children, and some old family servants, assembled at slough. exactly at noon the party walked several times in procession round the instrument; they then entered the gigantic tube, seated themselves on benches previously prepared, and chanted a requiem with english words composed by sir john herschel himself. then issuing from the tube, they ranged themselves around it, while its opening was hermetically sealed. * * * * * in march 1821, the younger herschel, in conjunction with sir james south, undertook a series of observations on the distances and positions of three hundred and eighty double and triple stars, by means of two splendid achromatic telescopes of five and seven focal length. these were continued during 1822 and 1823, and have proved of great service to astronomers. having pursued with much zeal the study of optics, and experimented largely and carefully on the double refraction and polarization of light, he compiled a treatise on the subject for the "encyclopaedia metropolitana" it has been translated into french by m. quetelet; and both foreign and english men of science have been accustomed to regard it as indicating a new point of departure in the important branch of science to which it is devoted. astronomy, however, became for him, as for his father, the great pursuit of his laborious life; and having constructed telescopes of singular magnitude and power, he entered upon a study of the sidereal world. in 1825 he commenced a careful re-examination of the numerous nebulae and starry clusters which had been discovered by his father, and described in the "philosophical transactions," fixing their positions and investigating their aspects. he devoted eight years to this _magnum opus_, completing it in 1832. the catalogue which he then contributed to the "philosophical transactions" includes 2306 nebulae and star-clusters, of which 525 were discovered by himself. while engaged in this difficult task, herschel discovered between three and four thousand double stars, which he described in the memoirs of the astronomical society. his observations were made with an excellent newtonian telescope, twenty feet in focal length, and eighteen and a half inches in aperture; and having obtained, to use his own expression, "a sufficient mastery over the instrument," the idea occurred to him of making it available for a survey of the southern heavens. accordingly, he left england on the 13th of november 1833, and arrived at cape town on the 16th of january 1834. five days later he wrote to his aunt as follows:- "here we are safely lauded and comfortably housed at the far end of africa; and having secured the landing and final storage of all the telescopes and other matters, as far as i can see, without the slightest injury, i lose no time in reporting to you our good success _so far_. m----[1] and the children are, thank god, quite well; though, for fear you should think her too good a sailor, i ought to add that she continued sea-sick, at intervals, during the whole passage. we were nine weeks and two days at sea, during which period we experienced only one day of contrary wind. we had a brisk breeze 'right aft' all the way from the bay of biscay (which we never entered) to the 'calm latitudes;' that is to say, to the space about five or six degrees broad near the equator, where the trade-winds cease, and where it is no unusual thing for a ship to lie becalmed for a month or six weeks, frying under a vertical sun. such, however, was not our fate. we were detained only three or four days by the calms usual in that zone, but never _quite_ still, or driven out of our course; and immediately on crossing 'the line' got a good breeze (the south-east trade-wind), which carried us round trinidad; then exchanged it for a north-west wind, which, with the exception of one day's squall from the south-east, carried us straight into table bay. on the night of the 14th we were told to prepare to see the table mountain. next morning (_n.b._, we had not seen land before since leaving england), at dawn, the welcome word land' was heard; and there stood this magnificent hill, with all its attendant mountain-range down to the farthest point of south africa, full in view, with a clear blue ghost-like outline; and that night we cast anchor within the bay. next morning early we landed, under escort of dr. stewart, m----'s brother, and you may imagine the meeting. we took up our quarters at a most comfortable lodging-house (miss robe's), and i proceeded, without loss of time, to unship the instruments. this was no trifling operation, as they filled (with the rest of our luggage) fifteen large boats; and, owing to the difficulty of getting them up from the hold of the ship, required several days to complete the landing. during the whole time (and indeed up to this moment) not a single south-east gale, the summer torment of this harbour, has occurred. this is a thing almost unheard of here, and has indeed been most fortunate, since otherwise it is not at all unlikely that some of the boats, laden as they were to the water's edge, might have been lost, and the whole business crippled. [footnote 1: herschel married a miss stewart in february 1826.] "for the last two or three days we have been looking at houses, and have all but agreed for one--a most beautiful place within four or five miles out of town, called 'the grove.' in point of situation it is a perfect paradise, in rich and magnificent mountain-scenery, and sheltered from all winds, even the fierce south-easter, by thick surrounding woods. i must reserve for my next all description of the gorgeous display of flowers which adorns this splendid country, as well as of the astonishing brilliancy of the constellations, which the calm, clear nights show off to great advantage." mr. herschel settled at feldhausen, about 142 feet above the sea, and in long. 22° 46' 9".11 e., and lat. 33° 58' 26".59 s. here he entered upon his great series of observations of the southern heavens, which he continued with unwearied ardour for a period of four years. the results were afterwards published, at the cost of the duke of northumberland, in a work entitled "results of astronomical observations made in 1834-35-36-37-38, at the cape of good hope." in this superb work, which placed its author on an equality with the most brilliant and illustrious astronomers, he defined and described 4015 of the nebulae and star-groups in the southern hemisphere, and 2995 of the double stars; besides entering into a variety of valuable particulars relative to halley's comet, the solar spots, the satellites of saturn, and the measurement of the apparent magnitude of stars. on his return to england (in 1838) the astronomer received a noble welcome. honours poured in upon him. the gold medal of the astronomical society was conferred upon him for a second time. william iv. had previously distinguished him with the hanoverian order of k.h.; but, on the coronation of queen victoria, he received a baronetcy; and in 1839 the university of oxford made him a d.c.l. continuing his career of scientific industry, he issued, in 1849, his important and very valuable treatise entitled "outlines of astronomy." in 1845, he was appointed president of the british association; and in 1848, of the royal astronomical society. to his other honours was added that of chevalier of the prussian order, "pour la mérite," founded by frederick the great, and bestowed at all times with a discrimination which renders it a deeply-coveted distinction. of the academies and leading scientific institutions of the continent and the united states, he was also an honorary or corresponding member. besides his works on meteorology and physical geography, he published, in 1867, an admirable little volume--"familiar lectures on scientific subjects." in this he showed that he could write with as much ease and intelligibility for the general public as for the higher order of scientific inquirers. his style in this valuable manual of information has a charm of its own, and entices the reader into the consideration of subjects apparently abstruse. he is earned on from page to page without any great mental effort, and finds himself rapidly mastering difficulties which he had been accustomed to regard as insuperable. let us take the first lecture on "volcanoes and earthquakes," and obtain a glimpse of herschel's mode of treatment. he refers to the greater and more permanent agencies which affect the configuration of our planet. everywhere, he says, and along every coast-line, we see the sea warring against the land, and overcoming it; wearing it and eating it down, and battering it to pieces; grinding those pieces to powder; carrying that powder away, and spreading it out over its own bottom, by the continued effect of the tides and currents. what a scene of continual activity is presented by the chalk-cliffs of old england! how they are worn, and broken up, and fantastically sculptured by the influence of winds and waters! precipices cut down to the sea-beach, constantly hammered by the waves, and constantly crumbling; the beach itself made of the flints outstanding after the softer chalk has been ground down and washed away; themselves grinding one another under the same ceaseless discipline--first rounded into pebbles, then worn into sand, and then carried further and further down the slope, to be replaced by fresh ones from the same source. here the likeness of an old gothic cathedral, with lofty arch, and shapely pinnacle; there the similitude of a mass of medieval fortifications, with crumbling battlements and shattered towers! the same thing, the same waste and wear, is going on everywhere, round every coast. the rivers contribute their share to the great work of change. look at the sand-banks at the mouth of the thames. what are they, says sir john herschel, but the materials of our island carried out to sea by the stream? the ganges carries away from the soil of india, and delivers into the sea, twice as much solid substance weekly as is contained in the great pyramid of egypt. the irawaddy sweeps off from burmah sixty-two cubic feet of earth in every second of time, on an average sometimes vast amount of earthy materials is transferred from one locality to another by river agency, as is the case in the deltas of the nile and the mississippi. these changes operate silently, continuously, and unperceived by the ordinary observer; but nature does not limit herself always and everywhere to such peaceful agencies. at times, and in certain places, she acts with startling abruptness and extraordinary violence. let the volcano and the earthquake attest the immensity of her power. let the earthquake tell how, within the memory of man, the whole coast-line of chili, for 100 miles about valparaiso, with the mighty chain of the andes, was hoisted at one blow, and in a single night (november 19, 1822), from two to seven feet above its former level, leaving the beach below the old low-water mark high and dry. one of the andean peaks upheaved on this occasion was the colossal mass of aconcagua, which overlooks valparaiso, and measures nearly 24,000 feet in height. on the same occasion, at least 10,000 square miles of country were estimated as having been upheaved; and the upheaval was not confined to the land, but extended far away to sea,--which was proved by the soundings off valparaiso and along the coast having been found considerably shallower than they were before the shock. in the year 1819, in an earthquake in india, in the district of cutch, bordering on the indus, a tract of country more than fifty miles long and sixteen miles broad was suddenly raised _ten feet_ above its former level. the raised portion still stands up above the unraised, like a long perpendicular rampart, known by the name of ullah bund, or god's wall. * * * * * with a similar fertility of illustration, herschel sets before us the phenomena of volcanic eruptions and their extraordinary effects. in a district of mexico, between the two streams of the cintimba and the san pedro, on the 28th of september 1789, a whole tract of ground, from three to four miles in extent, surged up like a foam-bubble, or the swell of a wave, to a height of upwards of 500 feet. flames, lurid and crackling, broke forth over a surface of more than half a square league; and the earth, as if softened by heat, was seen to rise and sink like the rolling tide. vast chasms opened in the earth, into which the two rivers poured their waters headlong; reappearing afterwards at no great distance from a cluster of _hornitos_, or small volcanic cones, which sprang out of the mighty mud-torrent that gradually covered the entire plain. wonderful and awful as were these phenomena, they were surpassed by the sudden opening of a chasm which vomited forth fire, and red-hot stones and ashes, until they accumulated in a range of six large mountain masses,--one of which, now known as the volcano of jorullo, attains an altitude of 1690 feet above the ancient level. in like manner sir john proceeds to describe an eruption of mount tomboro, in the island of sumbawa, the influence of which was felt to a distance of 1000 miles from its centre, in strange tremulous motions of the earth, and in the clash and clang of loud explosions. he says that he had seen it computed that the quantity of ashes and lava ejected in the course of this tremendous eruption would have formed three mountains of the size of mont blanc. as to the nature of the forces which operate to produce this astounding result, herschel puts forward a theory of singular simplicity and directness. "the origin," he says, "of such an enormous power thus occasionally exerting itself, will no doubt seem very marvellous--little short, indeed, of miraculous intervention; but the mystery, after all, is not quite so great as at first it seems. we are permitted to look a little way into these great secrets of nature; not far enough, indeed, to clear up every difficulty, but quite enough to penetrate us with admiration of that wonderful system of counterbalances and compensations, that adjustment of causes and consequences, by which, throughout all nature, evils are made to work their own cure, life to spring out of death, and renovation to tread in the steps and efface the vestiges of decay." and he finds the clew to the secret, the key of the whole matter, in the earth's vast central heat. this it is which produces the convulsions that change the terrestrial configuration, and fill the minds of men with fear and awe. conceive of "a sea of fire, on which we are all floating, land and sea,"--a boiling, seething, incandescent reservoir in the centre of our planet; and the solution of the problem will seem to you not difficult. such a sea would necessarily roll its liquid matter to and fro; and the removal of ever so small a portion from one point to another on the earth's surface would tend to disturb the equilibrium of the floating mass; just as, when a ship is launched into the river, the water it displaces is carried to the opposite bank with greater or less violence, according to the amount of displacement. it is impossible, adds herschel, but that this increase of pressure in some places and relief in others must be very unequal in their bearings. so that at some point or another our planet's floating crust must be brought into a state of strain, and if there be a weak or a soft part a crack will at last take place. this is exactly what happened in the earthquake which originated the allah bund, or god's wall, in cutch. volcanic eruptions are easily explicable on this principle,--the volcano being simply a vent for the passage of heated and molten matter, which the elevating pressure of the liquid below tends to eject. it is a well-known fact that volcanoes and earthquake-centres are nearly all situated on the borders or in the immediate neighbourhood of seas and oceans; and the reason would seem to be, that at such positions the accumulation of transported matter would necessarily attain its maximum, to whatever cause it might be due. then again, as herschel points out, the eruption of scorite and lava from the mouths of volcanoes, the result of the upward movement of the fiery liquid below, compensates in some degree for the downward transfer of material by detritus and alluvial deposits. hence it may be inferred that, on the whole, the quantity of solid matter above the ocean-level probably remains nearly always at the same amount. * * * * * it is with this ease and lucidity that sir john deals with scientific subjects of the greatest importance,--his genius resembling the elephant's trunk, which can balance a straw or rend an oak. in private life he displayed a simplicity of manner in harmony with the general unassumingness of his character. in his books as in society, in society as in his books, he was the same,--that is, free from all ostentation, free from self-pride, free from the arrogance of superior knowledge, and as ready to unbend himself to a child as to discourse with men of science. his career was a tranquil and a prosperous one, and, apart from the record of his discoveries and his honours, presents nothing of interest. he was peculiarly happy in his domestic relations; and in the wide circle of friends attracted by the mingled charm of his intellect and manners. a devout christian, a man of generosity and culture, a philosopher of great breadth of view and infinite patience of research,--we can place few better or brighter examples before our english youth than sir john herschel. chapter v. we could not conclude our notice of this remarkable family without some further allusion to its not least remarkable member--caroline lucretia herschel. to her varied accomplishments, her astronomical researches, and, above all, to her unwearied and unselfish devotion to her brother william, we have already made frequent allusion. she seemed to live for him and in him, to live for his fame and prosperity; and she poured out at his feet the treasures of an inexhaustible affection. to assist him in his labours, at whatever sacrifice, was her sole object in life; and she was certainly more careful for his reputation than was he himself. during his declining years she was his principal stay and support, and she was in daily attendance to note down or to calculate the results of his observations. his death was a severe blow to her; but, with characteristic courage, she retired to hanover, gave herself up to scientific pursuits, and in comparative solitude spent her later years. her biographer writes:- "when all was over, her only desire seems to have been to hurry away. hardly was her brother laid in his grave than she collected the few things she cared to keep, and left for ever the country where she had spent fifty years of her life, living and toiling for him and him only. 'if i should leave off making memorandums of such events as affect or are interesting to me, i should feel like what i am,--namely, a person that has nothing more to do in this world.' mournful words! doubly mournful, when we know that the writer had nearly half an ordinary lifetime still between her and that grave which she made haste to prepare, in the hope that her course was nearly run. who can think of her, at the age of seventy-two, heart-broken and desolate, going back to the home of her youth in the fond expectation of finding consolation, without a pang of sympathetic pity? she found everything changed." _that_, indeed, is to all of us the greatest grief, when we return to the home of our youth. it is as if, during the years of our absence, we had expected everything to stand as still as in the palace of the sleeping beauty while the charm rested upon it. we are fain to see the trees in their young greenness as when they sheltered our childhood, to find the hedgerows blooming with the same violets, to hear the mill-stream murmuring with the same music. time furrows our brows with wrinkles, and streaks our hair with silver; our hearts grow colder; our minds lose their elasticity and freshness; our friends pass away from our side. but still we think to ourselves that in the old scenes all things are as they were. we say to ourselves: the bird sings as of old in the elm-trees at the garden-foot; the rose-bush blossoms as of old against our favourite window. "the varying year with blade and sheaf clothes and re-clothes the happy plains; here rests the sap within the leaf, here stays the blood along the veins. faint shadows, vapours lightly curled, faint murmurs from the meadows come, like hints and echoes of the world to spirits folded in the womb." * * * * * but we regain the old familiar places, and, alas! we find that change has been as busy with them as with us. the signs of decay are upon the trees; the brook has ceased to flow; the rose-bush has withered to the ground. there are trees as green and streams as musical and flowers as sweet as in our youth; but they are not the streams or flowers or trees which delighted us, and to us they can never be as dear. but a worse alteration has taken place than any visible in the face of nature. we discover that we have lost the old habits, the old capacity of enjoyment; and we soon discover that it was the sympathies, the hopes, the aspirations of youth which, after all, lent to these early scenes their rare and irrecoverable attraction. and thus it was that miss herschel found everything changed. a life of fifty years spent in a certain routine and upon certain objects, had unfitted her to tread in the old paths. it soon became clear to her that all her ideas and feelings had been shaped and influenced in a totally different path. more bitter still, we are told, she came to know that in her great sorrow and inextinguishable love she was all alone. and bitterest of all was the feeling that, in losing her brother she had lost the glory of her life, the source of her intellectual enjoyment. "you don't know," she wrote to a friend, "the blank of life after having lived within the radiance of genius." yet to live in this blankness, and to do the best she could with it, became the work of caroline lucretia herschel at the age of threescore years and ten,--an age when most of us have already put off our cares and anxieties, but when she began to enter on a new life, with new habits, new duties, and new associations. her interest in astronomical pursuits never slackened, and she watched with eagerness the labours and successes of her nephew. the respect paid to her in society as a "woman of science" was not unwelcome, though she affected to make light of it. "you must give me leave," she wrote to sir john, "to send you any publications you can think of, without mentioning anything about paying for them. for it is necessary i should every now and then lay out a little of my spare cash in that, for the sake of supporting the reputation of being a learned lady; (there is for you!) for i am not only looked at for such a one, but even stared at here in hanover!" it was with unaffected modesty she deprecated the honorary membership of the irish academy, conferred on one who, she said, had not for many years discovered even a comet; yet she was by no means insensible to the distinction. every man of scientific eminence who visited hanover visited this aged lady; and her presence in the theatre, even in her latest years, was a constant source of attraction. such was the simple frugality of her habits, that she experienced an actual difficulty in disposing of her income. she affirmed that the largest sum she could spend upon herself was £50 a year; and the annual pension of £100, left by her brother, she refused, or else devoted the quarterly or half-yearly payment to the purchase of some handsome present for her nephew or niece. such was caroline lucretia herschel; and as such she was a remarkable proof that the rarest womanly gifts of affectionate forethought and loving devotion may exist in combination with intellectual strength and scientific enthusiasm. of the force, keenness, and permanency of her sisterly love, an illustration of a pathetic character occurs in a letter which she addressed to her nephew, february 27, 1823:- "i am grown much thinner than i was six months ago: when i look at my hands, they put me so in mind of what your dear father's were, when i saw them tremble under my eyes, as we latterly played at backgammon together." it has long been the reproach of england that she treats, or rather that her government treats, her men of science, her artists, and her litterateurs with a disgraceful parsimony. it would appear from the following letter that sir william herschel was inadequately rewarded, and that his sister felt this keenly:- "there can be no harm," she says, "in telling my own dear nephew that i never felt satisfied with the support your father received towards his undertakings, and far less with the ungracious manner in which it was granted. for the last sum came with a message that more must never be asked for. (oh! how degraded i felt, even for myself, whenever i thought of it!) and after all it came too late, and was not sufficient; for if expenses had been out of question, there would not have been so much time, and labour, and expense, for twenty-four men were at times by turns, day and night, at work, wasted on the first mirror, which had come out too light in the casting (alex more than once would have destroyed it secretly, if i had not persuaded him against it); and without two mirrors, you know, such an instrument cannot be always ready for observing. "but what grieved me most was that to the last your poor father was struggling above his strength against difficulties which he well knew might have been removed if it had not been attended with too much expense. the last time the mirror was obliged to be taken from the polisher on account of some obstacle, i heard him say (in his usual manner of thinking aloud on such occasions), 'it is impossible to make the machine act as required without a room three times as large as this.' "i must say a few words of apology for the good king (george iii.), and ascribe the close bargains which were made between him and my brother to the _shabby, mean-spirited advisers_ who were undoubtedly consulted on such occasions; but they are dead and gone, and no more of them." in february 1828, the great services which this high-souled woman had rendered to astronomical science were fitly rewarded by the presentation to her of the royal astronomical society's gold medal,--the greatest honour which an astronomer can receive. mr. south, himself an astronomer of deserved repute, was charged with the duty of presenting the medal; and in the course of his address he dwelt on the labours of her brother, and the share she had had in them. sir william's first catalogue of new nebulae and clusters of stars, he said, amounting in number to one thousand, was compiled with observations made from a twenty-foot reflector in the years 1783, 1784, and 1785. by the same instrument he was enabled to discover the positions of a second thousand of these distant worlds in 1785 to 1788; while the places of five hundred others were registered on the celestial map between 1788 and 1802. what, we may ask, were the discoveries of columbus compared with these? he revealed to europe the existence of only a single continent; herschel unfolded to man the mysteries of the depths of the heavens. but, continued mr. south, when we have thus enumerated the results obtained in the course of "sweeps" with this instrument, and taken into consideration the extent and variety of the other observations which were at the same time in progress, a most important part yet remains untold. who participated in his toils? who braved with him all the experiences of inclement weather? who shared, and consoled him in, his privations? a woman. and who was she? his sister. miss herschel it was who by night acted as his amanuensis; she it was whose pen conveyed to paper his observations as they issued from his lips; she it was who noted the various aspects and phenomena of the objects observed; she it was who, after spending the still night beside the wonder-exhibiting instrument, carried the rough, blurred manuscripts to her cottage at daybreak, and by the morning produced a clean copy and register of the night's achievements; she it was who planned the labour of each succeeding night; she it was who reduced into exact form every calculation; she it was who arranged the whole in systematic order; and she it was who largely assisted her illustrious brother to obtain his imperishable renown. miss herschel's claims to the gratitude of men of science, and to the admiration of all who can appreciate the beauty of self-sacrifice, did not end here. she was herself an astronomer, and an original observer. at times her brother was enabled to dispense with her attendance. you would suppose that such leisure nights she would gladly give up to rest. not she. her brother might, at some unforeseen moment, require her aid, and consequently she preferred to be close at hand. a seven-foot telescope planted on the lawn helped to while away the hours of waiting; and it was to the occupation of these hours that science owed the discovery of the comet of 1786, of the comet of 1788, of the comet of 1791, of the comet of 1793, and of that of 1795, now connected with the name of encke. many, also, of the nebulae contained in sir william herschel's catalogues were detected by her keen and accurate gaze during these nights of lonely observation. indeed, as south remarked, when looking at the joint-labours of these two enthusiasts, we scarcely know whether the warmer praise should be given to the intellectual might of the brother or the ardent industry of the sister. in 1797, continued her eulogist, she presented to the royal society a catalogue of 560 stars, taken from flamsteed's observations, the exact positions of which had not been previously defined. soon after the death of him to whom she had given up so much of her life, her best energies, and her ripest faculties, she returned to hanover,--unwilling, however, to relinquish the astronomical researches which had been so pure and permanent a source of pleasure. she undertook and completed the laborious "reduction" or registration of the places of 2500 nebulae, down to the 1st of january 1800; thus presenting in one view the results of all the observations sir william herschel had made upon those wonderful bodies, and triumphantly bringing to a close half a century of scientific toil. * * * * * we return to miss herschel's biography, in order to gather up a few particulars of her last years, and to exhibit some of the tenderer features of her character. on the occasion of her nephew's marriage, in 1829, she wrote to him in the following terms:- "my dearest nephew,--i have spent four days in vain endeavours to gain composure enough to give you an idea of the joyful sensation your letter of february 5th has caused me. but i can at this present moment find no words which would better express my happiness than those which escaped in exclamation from my lips, according to simeon (see st. luke ii. 29), 'lord, now lettest thou thy servant depart in peace.' "i have now some hopes of passing the few remainder of my days in as much comfort as the separation from the land where i spent the greatest portion of my life, and from all those which are most dear to me, can admit. for, from the description given me of the dear young lady of your choice, i am confident my dear nephew's future happiness is now established. "i beg you will give my love to your dear lady, and best regards to all your new connections where they are due, in the best terms you can think of, for i am at present too unwell for writing all i could wish to say. "i have suffered much during this severe winter, and have not been able to leave my habitation above three or four times for the last three months; and feel, moreover, much fatigued by sitting eight times within the last ten days to professor tiedemann for having my picture taken--which he did at my apartment, and now he has taken it home to finish. i must conclude, for i wish to say a few words to your dear mother. it is now between eleven and twelve, and perhaps you are at this very moment receiving the blessing of dr. jennings; in which i most fervently join by saying, 'god bless you both!'" though eighty-three years old, miss herschel retained all her old powers of memory; and in a letter to her new niece, lady herschel, written in 1833, she narrated some amusing reminiscences of her nephew's early childhood. he was only in his sixth year, she said, when she was separated for a while from the family circle. but this did not hinder "john" and her from remaining the most affectionate friends, and many a half or whole holiday he spent with her, devoting it to chemical experiments, in which all kinds of boxes, tops of tea-canisters, pepper-cruets, tea-cups, and the like, served for the necessary vessels, and the sand-tub furnished the matter to be analysed. miss herschel's task was to prevent the introduction of water, which would have produced havoc on her carpet. for his first notion of building, "john" was indebted to the affection of his aunt, who, on his second or third birthday, lifted him in the trenches to lay the south corner-stone of the building which was added to sir william's original house at slough. on further reflection, she felt convinced that this incident occurred in the second year of her nephew's age, for she remembered being obliged to use "a deal of coaxing" to make him part with the money he was to lay on the comer-stone. about the same time, when she was sitting near him one day, listening to his prattle, her attention was drawn to his repeated and formidable hammering. on investigating into its object, she found that it was the continuation of the labour of many days, during which he had undermined the ground about the corner of the house, had entirely removed the corner-stone, and was zealously toiling to overthrow the next! his aunt gave the alarm, and old john wiltshire, a favourite carpenter, ran to the spot, exclaiming, "heaven bless the boy! if he is not going to pull the house down!" * * * * * in 1834, sir john, as already stated, made a voyage to the cape of good hope, in order to undertake a series of observations of the southern heavens. his aunt had now reached the ripe old age of eighty-four, an age attained by few,--and when attained, bringing with it in almost every case a painful diminution of physical energy, and a corresponding decline in mental force. but such was not the case with this remarkable woman. she still continued an active correspondence with her nephew, and manifested the liveliest interest in all his movements. it is astonishing to mark the vivacity and clearness of the letters she wrote at this advanced period of her life. thus, on the 1st of may 1834, she writes to sir john:- "both yourself and my dear niece urged me to write often, and to write always twice; but, alas! i could not overcome the reluctance i felt of [at] telling you that it is over with me for getting up at eight or nine o'clock, dressing myself, eating my dinner alone without an appetite, falling asleep over a novel (i am obliged to lay down to recover the fatigue of the morning's exertions), awaking with nothing but the prospect of the trouble of getting into bed, where very seldom i get above two hours' sleep. it is enough to make a parson swear! to this i must add, i found full employment for the few moments, when i could rouse myself from a melancholy lethargy, to spend in looking over my store of astronomical and other memorandums of upwards of fifty years' collecting." later in the year she writes:- "i know not how to thank you sufficiently for the cheering account you give of the climate agreeing so well with you and all who are so dear to me, and that you find all about you so agreeable and comfortable;... so that i have nothing left to wish for but a continuation of the same, and that i may only live to see the handwriting of your dear caroline, though i have my doubts about lasting till then, for the thermometer standing 80° and 90° for upwards of two mouths, day and night, in nay rooms (to which i am mostly confined), has made great havoc in my brittle constitution. i beg you will look to it that she learns to make her figures as you find them in your father's mss., such as he taught me to make. the daughter of a mathematician must write plain figures. "my little grand-nephew making alliance with your workmen shows that he is taking after his papa. i see you now in idea, running about in petticoats among your father's carpenters, working with little tools of your own; and john wiltshire (one of pitt's men, whom you may perhaps remember) crying out, 'dang the boy, if he can't drive in a nail as well as i can!' "i thank you for the astronomical portion of your letter, and for your promise of future accounts of uncommon objects. it is not _clusters of stars_ i want you to discover in the body of the scorpion [the astronomical sign, so called], or thereabout, for that does not answer my expectation, remembering having once heard your father, after a long, awful silence, exclaim, 'hier ist wahrhaftig ein loch ein himmel!' [here, indeed, is a great gap in heaven!], and, as i said before, stopping afterwards at the same spot, but leaving it unsatisfied." these extracts may seem trivial to some of our readers, but they are not so, rightly considered. they illustrate the wonderful mental vivacity of their venerable writer, and in this respect are useful; but still more useful in showing how cheerfully she bore the burden of her years, and with what intellectual serenity she looked forward to her end. we own that the lives of the herschels are what the world would call uneventful. the discovery of a new planet, or of the orbit of a star, seems less romantic to the vulgar taste than the slaughter of ten thousand men on a field of battle. it will seem to the unthinking that the victorious general or the daring seaman, the leader of a forlorn hope, or the captain who goes down with his sinking ship, affords an example worthier of imitation than the patient, watchful, enthusiastic astronomer or his devoted sister. _his_, they will say, was a noble life. be it so; but every life is noble which is spent in the path of duty. do what comes to your hand to do with all honesty and completeness, and you will make _your_ life noble. subdue your passions, master your evil thoughts, observe the laws of temperance and purity, be truthful, be firm, be honest, and keep ever before you the law of christ as the law of your daily work, and you will make _your_ life noble. we cannot all be great commanders or daring captains, we cannot all be distinguished men of science; but we can all be righteously-living men, endeavouring to raise others by our example, and it is a higher aim to live purely than to live successfully. we cannot all command the success, just as we do not all enjoy the intellectual powers, of a herschel; but we can emulate the industry and perseverance of the astronomer, we can copy the devoted affection and self-denial of his sister. the sorriest mistake of which men can be guilty,--yet it is a mistake which has clouded many lives,--is to suppose that duty is less imperative in its claims on the humble and unknown than on men raised or born to eminent position. let it be understood and remembered that each one of us can rise to a standard of true heroism, by cultivating the graces of the christian character, and doing the work which god has appointed. * * * * * sir john herschel returned to england in 1838, and in july of the same year he and his little son paid a visit to miss herschel. it is characteristic that her intense anxiety as to the proper treatment of her little grand-nephew--his sleep, his food, his playthings--greatly disturbed her peace. "i rather suffered him," she writes, "to hunger, than would let him eat anything hurtful; indeed, i would not let him eat anything at all unless his papa was present." her biographer remarks, that great as was her joy to see once more almost the only living being upon whom she poured some of that wealth of affection with which her heart never ceased to overflow, yet it was on the disappointments and shortcomings of those few days, those precious days, that she chiefly dwelt; and the abrupt termination of her nephew's visit filled her with the deepest sorrow. with the generous, but, as it proved, mistaken intention of sparing her feelings, her nephew left without informing her beforehand of the exact time of his departure, simply bidding her good-night prior to his return to his inn. great was her distress when she found that he and his son had quitted hanover at four o'clock on the following morning. her introduction to her grand-nephew, as described by his father, sir john, was exceedingly quaint:- "now, let me tell you how tilings fell out. dr. groskopff took willie with him to aunty, but without saying who he was. says she, 'what little boy is that?' says he, 'the son of a friend of mine. ask him his name.' however, willie would not tell his name. 'where do you come from, little fellow?' 'from the cape of good hope,' says willie. 'what is that he says?' 'he says he comes from the cape of good hope.' 'ay! and who is he? what is his name?' 'his name is herschel.' 'yes,'says willie. 'what is that he says?' 'he says he comes from the cape of good hope.' 'ay! and who is he? what is his name?' 'his name is herschel.' 'yes,' says willie, 'william james herschel.' 'ach, mem gott! das nicht möglich; ist dieser kleines neffeu's sohn?' and so it all came out; and when i came to her all was understood, and we sat down and talked as quietly as if we had parted but yesterday." * * * * * in a letter which she wrote to lady herschel in 1838, we find some reminiscences of her early years. she says that when, at the age of twenty-two, she first visited england, there was no kind of ornamental needle-work, knitting, plaiting hair, stringing beads and bugles, and the like, of which she did not make samples by way of mastering the art. as she was the only girl, and consequently the cinderella, of the family, she could not find time, however, for much self-improvement. she was not, for instance, a skilled musician, but she was able to play the second violin part of an overture or easy quartette. and it is worth notice that the herschels were something more than astronomers only. both sir william and his son, great as they were in their special department of science, took care to cultivate their minds generally; were mathematicians, chemists, geologists, and men of letters. and here is a lesson for our younger readers. the mind should always be diverted towards one particular object; it should be the aim of everybody to attain towards supreme excellence, if possible, in some one pursuit. on the other hand, he should gather knowledge, more or less, in every field, so as to avoid narrowness of view and poverty of idea. versatility does not necessarily mean superficiality; we may know much of many things, and more of one thing. a man who is only a botanist, shuts himself out from all the truest and deepest pleasures of knowledge. it may be very clever for a violinist to play on a single string; but he must play on _all_, if he would bring out the full harmonies of his instrument, and do justice to its extraordinary powers. * * * * * miss herschel's enjoyment of life, which, when not carried to an excess, is a christian duty, continued to the very last. when she was in her ninetieth year, she rose as usual every day, dressed, ate, drank, rested on her sofa, read and conversed with her numerous visitors; still taking an interest in science and literature, even in public affairs, and still occupying herself with all that concerned the evergrowing reputation of her nephew. of course, she could not escape the infirmities of old age, but by cheerfulness and patience she did her best to alleviate them. in recalling incidents of her early life, she frequently gave evidence of her good-humoured contentment. in 1840, writing to her niece, she refers to an incident which occurred in the early part of the forty-foot telescope's existence, when "god save the king" was sung in it by her brother and his guests, who rose from the dinner-table for the purpose, and entered the tube in procession. she adds that among the company were two misses stows, one of whom was a famous pianoforte player; some of the griesbachs (well-known musicians), who accompanied on the oboe, or any instrument they could get hold of; and herself, who was one of the nimblest and foremost to get in and out of the tube. "but now," she adds, "lack-a-day! i can hardly cross the room without help. but what of that? dorcas, in the _beggar's opera_, says, 'one cannot eat one's cake and have it too!'" she relates, in the same letter, a curious anecdote of the old and celebrated tube. before the optical apparatus was finished, many visitors took a pleasure in walking through it,--among the rest, on one occasion, king george iii. and the archbishop of canterbury. the latter following the king, and finding it difficult to proceed, his majesty turned and gave him his hand, saying, "come, my lord bishop; i will show you the way to heaven!" then, with that astonishing memory of hers, which kept its greenness until the very last, she notes that this occurred on august 17, 1787, when the king and queen, the duke of york, and some of the princesses were of the company. * * * * * from another letter we take a lively little picture of a christmas in hanover:-she had been told that keeping christmas in the german sense was coming to be very general in england; but her shrewd, practical turn of mind induced her to hope that the english would never go "such lengths in foolery." at hanover, she wrote, the tradespeople had been for many weeks in full employ, framing and mounting the embroideries of the ladies and girls of all classes; of _all_ classes, for not a folly or extravagancy existed among the great but it was imitated by the little. the shops were beautifully lighted up by gas, and the last three days before christmas all that could tempt or attract was exhibited in the market-places in booths lighted up in the evening, whither everybody hastened to gaze and to spend their money. cooks and housemaids presented one another with knitted bags and purses; the cobbler's daughter embroidered "neck-cushions" for her friend the butcher's daughter. these were made up by the upholsterer at great expense, lined with white satin; the upper part, on which the back rested, being wrought with gold, silver, and pearls. * * * * * but we must no longer delay the reader by our gossip. enough has been said to illustrate the character of a remarkable woman, and of those features of it--her cheerfulness, her patience, her industry, her devoted affection, her unselfishness--which all of us may be the better for studying and imitating. our limits compel us to draw our simple narrative to a close, and we must pass over the delight with which she received and read sir john herschel's great work, "cape observations,"--a noble monument of the perseverance and strenuous labour of genius; but of twofold interest to her, because it not only testified to the eminent qualities of her nephew, but brought to a noble conclusion the vast undertaking of that nephew's father and her own beloved brother--the survey of the nebulous heavens. a letter written by her friend miss becksdorff, on the 6th of january 1848, describes caroline herschel's last days:- "her decided objection to having her bed placed in a warmer room had brought on a cold and cough; and so firm was her determination to preserve her old customs, and not to yield to increasing infirmities, that when, upon her doctor's positive orders, i had a bed made up in her room, before she came to sit in it one day, it was not till two o'clock in the night that betty could persuade her to lie down in it. upon going to her the next morning, i had the satisfaction, however, of finding her perfectly reconciled to the arrangement; she now felt the comfort of being undisturbed, and she has kept to her bed ever since. her mental and bodily strength is gradually declining. but a few days ago she was ready for a joke. when mrs. clarke told her that general halkett sent his love, and 'hoped she would soon be so well again that he might come and give her a kiss, as he had done on her birthday,' she looked only archly at her, and said, 'tell the general that i have not tasted anything since i liked so well.' i have just left her, and upon my asking her to give me a message for her nephew, she said, 'tell them i am good for nothing,' and went to sleep again." on the 9th of january 1848 she breathed her last, passing away with a christian's tranquillity.[1] [footnote 1: the particulars recorded in the foregoing pages are chiefly taken from mrs. john herschel's very interesting "memoir and correspondence of caroline herschel."] * * * * * her body was followed to the grave by many of her relatives and friends, the royal carriages forming part of the funeral procession. the coffin was adorned with garlands of laurel and cypress and palm branches, sent by the crown-princess from herrnhausen; and the service was conducted in that same garrison-church in which, nearly a century before, she had been christened, and afterwards confirmed. and, as proving her love and fidelity to the last, in her coffin were placed, by her express desire, "a lock of her beloved brother's hair, and an old, almost obliterated almanac that had been used by her father." * * * * * may our readers be induced, by their perusal of these pages, to emulate the herschels--brother, sister, nephew--in all the bright and lovely qualities that ennoble life; in their fixity of purpose, their elevation of thought, their purity of character, their self-denial, their industry, their hopefulness, and their faith! [the following inscription is engraved on miss herschel's tomb. it begins: "hier ruhet die irdische hülle von carolina herschel, geboren zu hannover den 16ten marz 1750, gestorben, den 9ten januar 1848." but, for the convenience of our young readers, we give it in english:- here rests the earthly case of c a r o l i n e h e r s c h e l. born at hanover, march 10, 1750. died january 9, 1848. "the eyes of her now glorified were, while here below, directed towards the starry heavens. her own discoveries of comets, and her share in the immortal labours of her brother, william herschel, bear witness of this to succeeding ages. "the royal irish academy of dublin, and the royal astronomical society of london, enrolled her name among their members. "at the age of 97 years 10 months, she fell asleep in calm rest, and in the full possession of her faculties; following into a better life her father, isaac herschel, who lived to the age of 60 years, 2 months, 17 days, and has lain buried not far off since the 29th of march 1767." this epitaph was mainly written by miss herschel herself, and the allusion to her brother is characteristic.] the torch-bearers watchers of the sky by alfred noyes prefatory note this volume, while it is complete in itself, is also the first of a trilogy, the scope of which is suggested in the prologue. the story of scientific discovery has its own epic unity--a unity of purpose and endeavour--the single torch passing from hand to hand through the centuries; and the great moments of science when, after long labour, the pioneers saw their accumulated facts falling into a significant order--sometimes in the form of a law that revolutionised the whole world of thought--have an intense human interest, and belong essentially to the creative imagination of poetry. it is with these moments that my poem is chiefly concerned, not with any impossible attempt to cover the whole field or to make a new poetic system, after the lucretian model, out of modern science. the theme has been in my mind for a good many years; and the first volume, dealing with the "watchers of the sky," began to take definite shape during what was to me an unforgettable experience--the night i was privileged to spend on a summit of the sierra madre mountains, when the first trial was made of the new 100-inch telescope. the prologue to this volume attempts to give a picture of that night, and to elucidate my own purpose. the first tale in this volume plunges into the middle of things, with the revolution brought about by copernicus; but, within the tale, partly by means of an incidental lyric, there is an attempt to give a bird's-eye view of what had gone before. the torch then passes to tycho brahe, who, driven into exile with his tables of the stars, at the very point of death hands them over to a young man named kepler. kepler, with their help, arrives at his own great laws, and corresponds with galileo--the intensely human drama of whose life i have endeavoured to depict with more historical accuracy than can be attributed to much of the poetic literature that has gathered around his name. too many writers have succumbed to the temptation of the cry, "e pur si muove!" it is, of course, rejected by every reliable historian, and was first attributed to galileo a hundred years after his death. m. ponsard, in his play on the subject, succumbed to the extent of making his final scene end with galileo "frappant du pied la terre," and crying, "pourtant elle tourne." galileo's recantation was a far more subtle and tragically complicated affair than that. even landor succumbed to the easy method of making him display his entirely legendary scars to milton. if these familiar pictures are not to be found in my poem, it may be well for me to assure the hasty reader that it is because i have endeavoured to present a more just picture. i have tried to suggest the complications of motive in this section by a series of letters passing between the characters chiefly concerned. there was, of course, a certain poetic significance in the legend of "e pur si muove"; and this significance i have endeavoured to retain without violating historical truth. in the year of galileo's death newton was born, and the subsequent sections carry the story on to the modern observatory again. the form i have adopted is a development from that of an earlier book, "_tales of the mermaid tavern_" where certain poets and discoverers of another kind were brought together round a central idea, and their stories told in a combination of narrative and lyrical verse. "the torch-bearers" flowed all the more naturally into a similar form in view of the fact that tycho brahe, kepler, and many other pioneers of science wrote a considerable number of poems. those imbedded in the works of kepler--whose blazing and fantastic genius was, indeed, primarily poetic--are of extraordinary interest. i was helped, too, in the general scheme by those constant meetings between science and poetry, of which the most famous and beautiful are the visit of sir henry wotton to kepler, and the visit of milton to galileo in prison. even if science and poetry were as deadly opposites as the shallow often affirm, the method and scheme indicated above would at least make it possible to convey something of the splendour of the long battle for the light in its most human aspect. poetry has its own precision of expression and, in modern times, it has been seeking more and more for truth, sometimes even at the expense of beauty. it may be possible to carry that quest a stage farther, to the point where, in the great rhythmical laws of the universe revealed by science, truth and beauty are reunited. if poetry can do this, it will not be without some value to science itself, and it will be playing its part in the reconstruction of a shattered world. the passing of the old order of dogmatic religion has left the modern world in a strange chaos, craving for something in which it can unfeignedly believe, and often following will-o'-the-wisps. forty years ago, matthew arnold prophesied that it would be for poetry, "where it is worthy of its high destinies," to help to carry on the purer fire, and to express in new terms those eternal ideas which must ever be the only sure stay of the human race. it is not within the province of science to attempt a post-copernican justification of the ways of god to man; but, in the laws of nature revealed by science, and in "that grand sequence of events which"--as darwin affirmed--"the mind refuses to accept as the result of blind chance," poetry may discover its own new grounds for the attempt. it is easy to assume that all hope and faith are shallow. it is even easier to practise a really shallow and devitalising pessimism. the modern annunciation that there is a skeleton an inch beneath the skin of man is neither new nor profound. neither science nor poetry can rest there; and if, in this poem, an attempt is made to show that spiritual values are not diminished or overwhelmed by the "fifteen hundred universes" that passed in review before the telescope of herschel, it is only after the opposite argument--so common and so easy to-day--has been faced; and only after poetry has at least endeavoured to follow the torch of science to its own deep-set boundary-mark in that immense darkness of space and time. contents prologue i. copernicus ii. tycho brahe iii. kepler iv. galileo v. newton vi. william herschel conducts vii. sir john herschel remembers epilogue prologue the observatory at noon, upon the mountain's purple height, above the pine-woods and the clouds it shone no larger than the small white dome of shell left by the fledgling wren when wings are born. by night it joined the company of heaven, and, with its constant light, became a star. a needle-point of light, minute, remote, it sent a subtler message through the abyss, held more significance for the seeing eye than all the darkness that would blot it out, yet could not dwarf it. high in heaven it shone, alive with all the thoughts, and hopes, and dreams of man's adventurous mind. up there, i knew the explorers of the sky, the pioneers of science, now made ready to attack that darkness once again, and win new worlds. to-morrow night they hoped to crown the toil of twenty years, and turn upon the sky the noblest weapon ever made by man. war had delayed them. they had been drawn away designing darker weapons. but no gun could outrange this. "to-morrow night"--so wrote their chief--"we try our great new telescope, the hundred-inch. your milton's 'optic tube' has grown in power since galileo, famous, blind, and old, talked with him, in that prison, of the sky. we creep to power by inches. europe trusts her 'giant forty' still. even to-night our own old sixty has its work to do; and now our hundred-inch . . . i hardly dare to think what this new muzzle of ours may find. come up, and spend that night among the stars here, on our mountain-top. if all goes well, then, at the least, my friend, you'll see a moon stranger, but nearer, many a thousand mile than earth has ever seen her, even in dreams. as for the stars, if seeing them were all, three thousand million new-found points of light is our rough guess. but never speak of this. you know our press. they'd miss the one result to flash 'three thousand millions' round the world." to-morrow night! for more than twenty years, they had thought and planned and worked. ten years had gone, one-fourth, or more, of man's brief working life, before they made those solid tons of glass, their hundred-inch reflector, the clear pool, the polished flawless pool that it must be to hold the perfect image of a star. and, even now, some secret flaw--none knew until to-morrow's test--might waste it all. where was the gambler that would stake so much,-time, patience, treasure, on a single throw? the cost of it,--they'd not find that again, either in gold or life-stuff! all their youth was fuel to the flame of this one work. once in a lifetime to the man of science, despite what fools believe his ice-cooled blood, there comes this drama. if he fails, he fails utterly. he at least will have no time for fresh beginnings. other men, no doubt, years hence, will use the footholes that he cut in those precipitous cliffs, and reach the height, but he will never see it." so for me, the light words of that letter seemed to hide the passion of a lifetime, and i shared the crowning moment of its hope and fear. next day, through whispering aisles of palm we rode up to the foot-hills, dreaming desert-hills that to assuage their own delicious drought had set each tawny sun-kissed slope ablaze with peach and orange orchards. up and up, along the thin white trail that wound and climbed and zig-zagged through the grey-green mountain sage, the car went crawling, till the shining plain below it, like an airman's map, unrolled. houses and orchards dwindled to white specks in midget cubes and squares of tufted green. once, as we rounded one steep curve, that made the head swim at the canyoned gulf below, we saw through thirty miles of lucid air elvishly small, sharp as a crumpled petal blown from the stem, a yard away, a sail lazily drifting on the warm blue sea. up for nine miles along that spiral trail slowly we wound to reach the lucid height above the clouds, where that white dome of shell, no wren's now, but an eagle's, took the flush of dying day. the sage-brush all died out, and all the southern growths, and round us now, firs of the north, and strong, storm-rooted pines exhaled a keener fragrance; till, at last, reversing all the laws of lesser hills, they towered like giants round us. darkness fell before we reached the mountain's naked height. over us, like some great cathedral dome, the observatory loomed against the sky; and the dark mountain with its headlong gulfs had lost all memory of the world below; for all those cloudless throngs of glittering stars and all those glimmerings where the abyss of space is powdered with a milky dust, each grain a burning sun, and every sun the lord of its own darkling planets,--all those lights met, in a darker deep, the lights of earth, lights on the sea, lights of invisible towns, trembling and indistinguishable from stars, in those black gulfs around the mountain's feet. then, into the glimmering dome, with bated breath, we entered, and, above us, in the gloom saw that majestic weapon of the light uptowering like the shaft of some huge gun through one arched rift of sky. dark at its base with naked arms, the crew that all day long had sweated to make ready for this night waited their captain's word. the switchboard shone with elfin lamps of white and red, and keys whence, at a finger's touch, that monstrous tube moved like a creature dowered with life and will, to peer from deep to deep. below it pulsed the clock-machine that slowly, throb by throb, timed to the pace of the revolving earth, drove the titanic muzzle on and on, fixed to the chosen star that else would glide out of its field of vision. so, set free balanced against the wheel of time, it swung, or rested, while, to find new realms of sky the dome that housed it, like a moon revolved, so smoothly that the watchers hardly knew they moved within; till, through the glimmering doors, they saw the dark procession of the pines like indian warriors, quietly stealing by. then, at a word, the mighty weapon dipped its muzzle and aimed at one small point of light one seeming insignificant star. the chief, mounting the ladder, while we held our breath, looked through the eye-piece. then we heard him laugh his thanks to god, and hide it in a jest. "a prominence on jupiter!"- they laughed, "what do you mean?"--"it's moving," cried the chief, they laughed again, and watched his glimmering face high overhead against that moving tower. "come up and see, then!" one by one they went, and, though each laughed as he returned to earth, their souls were in their eyes. then i, too, looked, and saw that insignificant spark of light touched with new meaning, beautifully reborn, a swimming world, a perfect rounded pearl, poised in the violet sky; and, as i gazed, i saw a miracle,--right on its upmost edge a tiny mound of white that slowly rose, then, like an exquisite seed-pearl, swung quite clear and swam in heaven above its parent world to greet its three bright sister-moons. a moon, of jupiter, no more, but clearer far than mortal eyes had seen before from earth, o, beautiful and clear beyond all dreams was that one silver phrase of the starry tune which galileo's "old discoverer" first dimly revealed, dissolving into clouds the imagined fabric of our universe. _"jupiter stands in heaven and will stand though all the sycophants bark at him,"_ he cried, hailing the truth before he, too, went down, whelmed in the cloudy wreckage of that dream. so one by one we looked, the men who served urania, and the men from vulcan's forge. a beautiful eagerness in the darkness lit the swarthy faces that too long had missed a meaning in the dull mechanic maze of labour on this blind earth, but found it now. though only a moment's wandering melody hopelessly far above, it gave their toil its only consecration and its joy. there, with dark-smouldering eyes and naked throats, blue-dungareed, red-shirted, grimed and smeared with engine-grease and sweat, they gathered round the foot of that dim ladder; each muttering low as he came down, his wonder at what he saw to those who waited,--a picture for the brush of rembrandt, lighted only by the rift above them, where the giant muzzle thrust out through the dim arched roof, and slowly throbbed, against the slowly moving wheel of the earth, holding their chosen star. there, like an elf, perched on the side of that dark slanting tower the italian mechanician watched the moons, that italy discovered. one by one, american, english, french, and dutch, they climbed to see the wonder that their own blind hands had helped to achieve. at midnight while they paused to adjust the clock-machine, i wandered out alone, into the silence of the night. the silence? on that lonely height i heard eternal voices; for, as i looked into the gulf beneath, whence almost all the lights had vanished now, the whole dark mountain seemed to have lost its earth and to be sailing like a ship through heaven. all round it surged the mighty sea-like sound of soughing pine-woods, one vast ebb and flow of absolute peace, aloof from all earth's pain, so calm, so quiet, it seemed the cradle-song, the deep soft breathing of the universe over its youngest child, the soul of man. and, as i listened, that aeolian voice became an invocation and a prayer: o you, that on your loftier mountain dwell and move like light in light among the thoughts of heaven, translating our mortality into immortal song, is there not one among you that can turn to music now this long dark fight for truth? not one to touch with beauty this long battle for the light, this little victory of the spirit of man doomed to defeat--for what was all we saw to that which neither eyes nor soul could see?-doomed to defeat and yet unconquerable, climbing its nine miles nearer to the stars. wars we have sung. the blind, blood-boltered kings move with an epic music to their thrones. have you no song, then, of that nobler war? of those who strove for light, but could not dream even of this victory that they helped to win, silent discoverers, lonely pioneers, prisoners and exiles, martyrs of the truth who handed on the fire, from age to age; of those who, step by step, drove back the night and struggled, year on year, for one more glimpse among the stars, of sovran law, their guide; of those who searching inward, saw the rocks dissolving into a new abyss, and saw those planetary systems far within, atoms, electrons, whirling on their way to build and to unbuild our solid world; of those who conquered, inch by difficult inch, the freedom of this realm of law for man; dreamers of dreams, the builders of our hope, the healers and the binders up of wounds, who, while the dynasts drenched the world with blood, would in the still small circle of a lamp wrestle with death like heracles of old to save one stricken child. is there no song to touch this moving universe of law with ultimate light, the glimmer of that great dawn which over our ruined altars yet shall break in purer splendour, and restore mankind from darker dreams than even lucretius knew to vision of that one power which guides the world. how should men find it? only through those doors which, opening inward, in each separate soul give each man access to that soul of all living within each life, not to be found or known, till, looking inward, each alone meets the unknowable and eternal god. and there was one that moved like light in light before me there,--love, human and divine, that can exalt all weakness into power,-whispering, _take this deathless torch of song_... whispering, but with such faith, that even i was humbled into thinking this might be through love, though all the wisdom of the world account it folly. let my breast be bared to every shaft, then, so that love be still my one celestial guide the while i sing of those who caught the pure promethean fire one from another, each crying as he went down to one that waited, crowned with youth and joy,-_take thou the splendour, carry it out of sight into the great new age i must not know, into the great new realm i must not tread_. i copernicus the neighbours gossiped idly at the door. copernicus lay dying overhead. his little throng of friends, with startled eyes, whispered together, in that dark house of dreams, from which by one dim crevice in the wall he used to watch the stars. "his book has come from nuremberg at last; but who would dare to let him see it now?"- "they have altered it! though rome approved in full, this preface, look, declares that his discoveries are a dream!"-"he has asked a thousand times if it has come; could we tear out those pages?"- "he'd suspect."-"what shall be done, then?"- "hold it back awhile. that was the priest's voice in the room above. he may forget it. those last sacraments may set his mind at rest, and bring him peace."-then, stealing quietly to that upper door, they opened it a little, and saw within the lean white deathbed of copernicus who made our world a world without an end. there, in that narrow room, they saw his face grey, seamed with thought, lit by a single lamp; they saw those glorious eyes closing, that once had looked beyond the spheres and seen our ancient firmaments dissolve into a boundless night. beside him knelt two women, like bowed shadows. at his feet, an old physician watched him. at his head, the cowled franciscan murmured, while the light shone faintly on the chalice. all grew still. the fragrance of the wine was like faint flowers, the first breath of those far celestial fields.... then, like a dying soldier, that must leave his last command to others, while the fight is yet uncertain, and the victory far, copernicus whispered, in a fevered dream, "yes, it is death. but you must hold him back, there, in the doorway, for a little while, until i know the work is rightly done. use all your weapons, doctor. i must live to see and touch one copy of my book. have they not brought it yet? they promised me it should be here by nightfall. one of you go and hasten it. i can hold back death till dawn. have they not brought it yet?--from nuremberg. do not deceive me. i must know it safe, printed and safe, for other men to use. i could die then. my use would be fulfilled. what has delayed them? will not some one go and tell them that my strength is running out? tell them that book would be an angel's hand in mine, an easier pillow for my head, a little lantern in the engulfing dark. you see, i hid its struggling light so long under too small a bushel, and i fear it may go out forever. in the noon of life's brief day, i could not see the need as now i see it, when the night shuts down. i was afraid, perhaps, it might confuse the lights that guide us for the souls of men. but now i see three stages in our life. at first, we bask contented in our sun and take what daylight shows us for the truth. then we discover, in some midnight grief, how all day long the sunlight blinded us to depths beyond, where all our knowledge dies. that's where men shrink, and lose their way in doubt. then, last, as death draws nearer, comes a night in whose majestic shadow men see god, absolute knowledge, reconciling all. so, all my life i pondered on that scheme which makes this earth the centre of all worlds, lighted and wheeled around by sun and moon and that great crystal sphere wherein men thought myriads of lesser stars were fixed like lamps, each in its place,--one mighty glittering wheel revolving round this dark abode of man. night after night, with even pace they moved. year after year, not altering by one point, their order, or their stations, those fixed stars in that revolving firmament. the plough still pointed to the pole. fixed in their sphere, how else explain that vast unchanging wheel? how, but by thinking all those lesser lights were huger suns, divided from our earth by so immense a gulf that, if they moved ten thousand leagues an hour among themselves, it would not seem one hair's-breadth to our eyes. utterly inconceivable, i know; and yet we daily kneel to boundless power and build our hope on that infinitude. this did not daunt me, then. indeed, i saw light upon chaos. many discordant dreams began to move in lucid music now. for what could be more baffling than the thought that those enormous heavens must circle earth diurnally--a journey that would need swiftness to which the lightning flash would seem a white slug creeping on the walls of night; while, if earth softly on her axle spun one quiet revolution answered all. it was our moving selves that made the sky seem to revolve. have not all ages seen a like illusion baffling half mankind in life, thought, art? men think, at every turn of their own souls, the very heavens have moved. light upon chaos, light, and yet more light; for--as i watched the planets--venus, mars, appeared to wax and wane from month to month as though they moved, now near, now far, from earth. earth could not be their centre. was the sun their sovran lord then, as pythagoras held? was this great earth, so 'stablished, so secure, a planet also? did it also move around the sun? if this were true, my friends, no revolution in this world's affairs, not that blind maelstrom where imperial rome went down into the dark, could so engulf all that we thought we knew. we who believed in our own majesty, we who walked with gods as younger sons on this proud central stage, round which the whole bright firmament revolved for our especial glory, must we creep like ants upon our midget ball of dust lost in immensity? i could not take that darkness lightly. i withheld my book for many a year, until i clearly saw, and rome approved me--have they not brought it yet?-that this tremendous music could not drown the still supernal music of the soul, or quench the light that shone when christ was born. for who, if one lost star could lead the kings to god's own son, would shrink from following these to his eternal throne? this at the least we know, the soul of man can soar through heaven. it is our own wild wings that dwarf the world to nothingness beneath us. let the soul take courage, then. if its own thought be true, not all the immensities of little minds can ever quench its own celestial fire. no. this new night was needed, that the soul might conquer its own kingdom and arise to its full stature. so, in face of death, i saw that i must speak the truth i knew. have they not brought it? what delays my book? i am afraid. tell me the truth, my friends. at this last hour, the church may yet withhold her sanction. not the church, but those who think a little darkness helps her. were this true, they would do well. if the poor light we win confuse or blind us, to the light of lights, let all our wisdom perish. i affirm a greater darkness, where the one true church shall after all her agonies of loss and many an age of doubt, perhaps, to come, see this processional host of splendours burn like tapers round her altar. so i speak not for myself, but for the age unborn. i caught the fire from those who went before, the bearers of the torch who could not see the goal to which they strained. i caught their fire, and carried it, only a little way beyond; but there are those that wait for it, i know, those who will carry it on to victory. i dare not fail them. looking back, i see those others,--fallen, with their arms outstretched dead, pointing to the future. far, far back, before the egyptians built their pyramids with those dark funnels pointing to the north, through which the pharaohs from their desert tombs gaze all night long upon the polar star, some wandering arab crept from death to life led by the plough across those wastes of pearl.... long, long ago--have they not brought it yet? my book?--i finished it one summer's night, and felt my blood all beating into song. i meant to print those verses in my book, a prelude, hinting at that deeper night which darkens all our knowledge. then i thought the measure moved too lightly. do you recall those verses, elsa? they would pass the time. how happy i was the night i wrote that song!" then, one of those bowed shadows raised her head and, like a mother crooning to her child, murmured the words he wrote, so long ago. in old cathay, in far cathay, before the western world began, they saw the moving fount of day eclipsed, as by a shadowy fan; they stood upon their chinese wall. they saw his fire to ashes fade, and felt the deeper slumber fall on domes of pearl and towers of jade. with slim brown hands, in araby, they traced, upon the desert sand, their rams and scorpions of the sky, and strove--and failed--to understand. before their footprints were effaced the shifting sand forgot their rune; their hieroglyphs were all erased, their desert naked to the moon. in bagdad of the purple nights, haroun al raschid built a tower, where sages watched a thousand lights and read their legends, for an hour. the tower is down, the caliph dead, their astrolabes are wrecked with rust. orion glitters overhead, aladdin's lamp is in the dust. in babylon, in babylon, they baked their tablets of the clay; and, year by year, inscribed thereon the dark eclipses of their day; they saw the moving finger write its _mene, mene_, on their sun. a mightier shadow cloaks their light, and clay is clay in babylon. a shadow moved towards him from the door. copernicus, with a cry, upraised his head. "the book, i cannot see it, let me feel the lettering on the cover. it is here! put out the lamp, now. draw those curtains back, and let me die with starlight on my face. an angel's hand in mine . . . yes; i can say my _nunc dimittis_ now . . . light, and more light in that pure realm whose darkness is our peace." ii tycho brahe i they thought him a magician, tycho brahe, who lived on that strange island in the sound, nine miles from elsinore. his legend reached the mermaid inn the year that shakespeare died. fynes moryson had brought his travellers' tales of wheen, the heart-shaped isle where tycho made his great discoveries, and, with jeppe, his dwarf, and flaxen-haired christine, the peasant girl, dreamed his great dreams for five-and-twenty years. for there he lit that lanthorn of the law, uraniborg; that fortress of the truth, with pegasus flying above its loftiest tower, while, in its roofs, like wide enchanted eyes watching, the brightest windows in the world, opened upon the stars. nine miles from elsinore, with all those ghosts, there's magic enough in that! but white-cliffed wheen, six miles in girth, with crowds of hunchback waves crawling all round it, and those moonstruck windows, held its own magic, too; for tycho brahe by his mysterious alchemy of dreams had so enriched the soil, that when the king of england wished to buy it, denmark asked a price too great for any king on earth. "give us," they said, "in scarlet cardinal's cloth enough to cover it, and, at every corner, of every piece, a right rose-noble too; then all that kings can buy of wheen is yours. only," said they, "a merchant bought it once; and, when he came to claim it, goblins flocked all round him, from its forty goblin farms, and mocked him, bidding him take away the stones that he had bought, for nothing else was his." these things were fables. they were also true. they thought him a magician, tycho brahe, the astrologer, who wore the mask of gold. perhaps he was. there's magic in the truth; and only those who find and follow its laws can work its miracles. tycho sought the truth from that strange year in boyhood when he heard the great eclipse foretold; and, on the day appointed, at the very minute even, beheld the weirdly punctual shadow creep across the sun, bewildering all the birds with thoughts of evening. picture him, on that day, the boy at copenhagen, with his mane of thick red hair, thrusting his freckled face out of his upper window, holding the piece of glass he blackened above his candle-flame to watch that orange ember in the sky wane into smouldering ash. he whispered there, "so it is true. by searching in the heavens, men can foretell the future." in the street below him, throngs were babbling of the plague that might or might not follow. he resolved to make himself the master of that deep art and know what might be known. he bought the books of stadius, with his tables of the stars. night after night, among the gabled roofs, climbing and creeping through a world unknown save to the roosting stork, he learned to find the constellations, cassiopeia's throne, the plough still pointing to the polar star, the sword-belt of orion. there he watched the movements of the planets, hours on hours, and wondered at the mystery of it all. all this he did in secret, for his birth was noble, and such wonderings were a sign of low estate, when tycho brahe was young; and all his kinsmen hoped that tycho brahe would live, serene as they, among his dogs and horses; or, if honour must be won, let the superfluous glory flow from fields where blood might still be shed; or from those courts where statesmen lie. but tycho sought the truth. so, when they sent him in his tutor's charge to leipzig, for such studies as they held more worthy of his princely blood, he searched the almagest; and, while his tutor slept, measured the delicate angles of the stars, out of his window, with his compasses, his only instrument. even with this rude aid he found so many an ancient record wrong that more and more he burned to find the truth. one night at home, as tycho searched the sky, out of his window, compasses in hand, fixing one point upon a planet, one upon some loftier star, a ripple of laughter startled him, from the garden walk below. he lowered his compass, peered into the dark and saw--christine, the blue-eyed peasant girl, with bare brown feet, standing among the flowers. she held what seemed an apple in her hand; and, in a voice that aprilled all his blood, the low soft voice of earth, drawing him down from those cold heights to that warm breast of spring, a natural voice that had not learned to use the false tones of the world, simple and clear as a bird's voice, out of the fragrant darkness called, "i saw it falling from your window-ledge! i thought it was an apple, till it rolled over my foot. it's heavy. shall i try to throw it back to you?" tycho saw a stain of purple across one small arched glistening foot. "your foot is bruised," he cried. "o no," she laughed, and plucked the stain off. "only a petal, see." she showed it to him. "but this--i wonder now if i can throw it." twice she tried and failed; or tycho failed to catch that slippery sphere. he saw the supple body swaying below, the ripe red lips that parted as she laughed, and those deep eyes where all the stars were drowned. at the third time he caught it; and she vanished, waving her hand, a little floating moth, between the pine-trees, into the warm dark night. he turned into his room, and quickly thrust under his pillow that forbidden fruit; for the door opened, and the hot red face of otto brahe, his father, glowered at him. "what's this? what's this?" the furious-eyed old man limped to the bedside, pulled the mystery out, and stared upon the strangest apple of eve that ever troubled eden,--heavy as bronze, and delicately enchased with silver stars, the small celestial globe that tycho bought in leipzig. then the storm burst on his head! this moon-struck 'pothecary's-prentice work, these cheap-jack calendar-maker's gypsy tricks would damn the mother of any knutsdorp squire, and crown his father like a stag of ten. quarrel on quarrel followed from that night, till tycho sickened of his ancient name; and, wandering through the woods about his home, found on a hill-top, ringed with fragrant pines, a little open glade of whispering ferns. thither, at night, he stole to watch the stars; and there he told the oldest tale on earth to one that watched beside him, one whose eyes shone with true love, more beautiful than the stars, a daughter of earth, the peasant-girl, christine. they met there, in the dusk, on his last night at home, before he went to wittenberg. they stood knee-deep among the whispering ferns, and said good-bye. "i shall return," he said, "and shame them for their folly, who would set their pride above the stars, christine, and you. at wittenberg or rostoch i shall find more chances and more knowledge. all those worlds are still to conquer. we know nothing yet; the books are crammed with fables. they foretell here an eclipse, and there a dawning moon, but most of them were out a month or more on jupiter and saturn. there's one way, and only one, to knowledge of the law whereby the stars are steered, and so to read the future, even perhaps the destinies of men and nations,--only one sure way, and that's to watch them, watch them, and record the truth we know, and not the lies we dream. dear, while i watch them, though the hills and sea divide us, every night our eyes can meet among those constant glories. every night your eyes and mine, upraised to that bright realm, can, in one moment, speak across the world. i shall come back with knowledge and with power, and you--will wait for me?" she answered him in silence, with the starlight of her eyes. ii he watched the skies at wittenberg. the plague drove him to rostoch, and he watched them there; but, even there, the plague of little minds beset him. at a wedding-feast he met his noble countryman, manderup, who asked, with mocking courtesy, whether tycho brahe was ready yet to practise his black art at country fairs. the guests, and tycho, laughed; whereat the swaggering junker blandly sneered, "if fortune-telling fail, christine will dance, thus--tambourine on hip," he struck a pose. "her pretty feet will pack that booth of yours." they fought, at midnight, in a wood, with swords. and not a spark of light but those that leapt blue from the clashing blades. tycho had lost his moon and stars awhile, almost his life; for, in one furious bout, his enemy's blade dashed like a scribble of lightning into the face of tycho brahe, and left him spluttering blood, groping through that dark wood with outstretched hands, to fall in a death-black swoon. they carried him back to rostoch; and when tycho saw at last that mirrored patch of mutilated flesh, seared as by fire, between the frank blue eyes and firm young mouth where, like a living flower upon some stricken tree, youth lingered still, he'd but one thought, christine would shrink from him in fear, or worse, in pity. an end had come worse than old age, to all the glory of youth. urania would not let her lover stray into a mortal's arms. he must remain her own, for ever; and for ever, alone. yet, as the days went by, to face the world, he made himself a delicate mask of gold and silver, shaped like those that minstrels wear at carnival in venice, or when love, disguising its disguise of mortal flesh, wooes as a nameless prince from far away. and when this world's day, with its blaze and coil was ended, and the first white star awoke in that pure realm where all our tumults die, his eyes and hers, meeting on hesperus, renewed their troth. he seemed to see christine, ringed by the pine-trees on that distant hill, a small white figure, lost in space and time, yet gazing at the sky, and conquering all, height, depth, and heaven itself, by the sheer power of love at one with everlasting laws, a love that shared the constancy of heaven, and spoke to him across, above, the world. iii not till he crossed the danube did he find among the fountains and the storied eaves of augsburg, one to share his task with him. paul hainzel, of that city, greatly loved to talk with tycho of the strange new dreams copernicus had kindled. did this earth move? was the sun the centre of our scheme? and tycho told him, there is but one way to know the truth, and that's to sweep aside all the dark cobwebs of old sophistry, and watch and learn that moving alphabet, each smallest silver character inscribed upon the skies themselves, noting them down, till on a day we find them taking shape in phrases, with a meaning; and, at last, the hard-won beauty of that celestial book with all its epic harmonies unfold like some great poet's universal song. he was a great magician, tycho brahe. "hainzel," he said, "we have no magic wand, but what the truth can give us. if we find even with a compass, through a bedroom window, that half the glittering almagest is wrong, think you, what noble conquests might be ours, had we but nobler instruments." he showed quivering with eagerness, his first rude plan for that great quadrant,--not the wooden toy of old scultetus, but a kingly weapon, huge as a roman battering-ram, and fine in its divisions as any goldsmith's work. "it could be built," said tycho, "but the cost would buy a dozen culverin for your wars." then hainzel, fired by tycho's burning brain, answered, "we'll make it. we've a war to wage on chaos, and his kingdoms of the night." they chose the cunningest artists of the town, clock-makers, jewellers, carpenters, and smiths, and, setting them all afire with tycho's dream, within a month his dream was oak and brass. its beams were fourteen cubits, solid oak, banded with iron. its arch was polished brass whereon five thousand exquisite divisions were marked to show the minutes of degrees. so huge and heavy it was, a score of men, could hardly drag and fix it to its place in hainzel's garden. many a shining night, tycho and hainzel, out of that maze of flowers, charted the stars, discovering point by point, how all the records erred, until the fame of this new master, hovering above the schools like a strange hawk, threatened the creeping dreams of all the aristotelians, and began to set their mouse-holes twittering "tycho brahe!" then tycho brahe came home, to find christine. up to that whispering glade of ferns he sped, at the first wink of hesperus. he stood in shadow, under the darkest pine, to hide the little golden mask upon his face. he wondered, will she shrink from me in fear or loathing? will she even come at all? and, as he wondered, like a light she moved before him. "is it you?"- "christine! christine," he whispered, "it is i, the mountebank, playing a jest upon you. it's only a mask! do not be frightened. i am here behind it." her red lips parted, and between them shone, the little teeth like white pomegranate seeds. he saw her frightened eyes. then, with a cry, her arms went round him, and her eyelids closed. lying against his heart, she set her lips against his lips, and claimed him for her own. iv one frosty night, as tycho bent his way home to the dark old abbey, he upraised his eyes, and saw a portent in the sky. there, in its most familiar patch of blue, where cassiopeia's five-fold glory burned, an unknown brilliance quivered, a huge star unseen before, a strange new visitant to heavens unchangeable, as the world believed, since the creation. could new stars be born? night after night he watched that miracle growing and changing colour as it grew; white at the first, and large as jupiter; and, in the third month, yellow, and larger yet; red in the fifth month, like aldebaran, and larger even than lyra. in the seventh, bluish like saturn; whence it dulled and dwined little by little, till after eight months more into the dark abysmal blue of night, whence it arose, the wonder died away. but, while it blazed above him, tycho brought those delicate records of two hundred nights to copenhagen. there, in his golden mask, at supper with pratensis, who believed only what old books told him, tycho met dancey, the french ambassador, rainbow-gay in satin hose and doublet, supple and thin, brown-eyed, and bearded with a soft black tuft neat as a blackbird's wing,--a spirit as keen and swift as france on all the starry trails of thought. he saw the deep and simple fire, the mystery of all genius in those eyes above that golden wizard. tycho raised his wine-cup, brimming--they thought--with purple dreams; and bade them drink to their triumphant queen of all the muses, to their lady of light urania, and the great new star. they laughed, thinking the young astrologer's golden mask hid a sardonic jest. "the skies are clear," said tycho brahe, "and we have eyes to see. put out your candles. open those windows there!" the colder darkness breathed upon their brows, and tycho pointed, into the deep blue night. there, in their most immutable height of heaven, in _ipso caelo_, in the ethereal realm, beyond all planets, red as mars it burned, the one impossible glory. "but it's true!" pratensis gasped; then, clutching the first straw, "now i recall how pliny the elder said, hipparchus also saw a strange new star, not where the comets, not where the _rosae_ bloom and fade, but in that solid crystal sphere where nothing changes." tycho smiled, and showed the record of his watchings. "but the world must know all this," cried dancey. "you must print it." "print it?" said tycho, turning that golden mask on both his friends. "could i, a noble, print this trafficking with urania in a book? they'd hound me out of denmark! this disgrace of work, with hands or brain, no matter why, no matter how, in one who ought to dwell fixed to the solid upper sphere, my friends, would never be forgiven." dancey stared in mute amazement, but that mask of gold outstared him, sphinx-like, and inscrutable. soon through all europe, like the blinded moths, roused by a lantern in old palaces among the mouldering tapestries of thought, weird fables woke and fluttered to and fro, and wild-eyed sages hunted them for truth. the italian, frangipani, thought the star the lost electra, that had left her throne among the pleiads, and plunged into the night like a veiled mourner, when troy town was burned. the german painter, busch, of erfurt, wrote, "it was a comet, made of mortal sins; a poisonous mist, touched by the wrath of god to fire; from which there would descend on earth all manner of evil--plagues and sudden death, frenchmen and famine." preachers thumped and raved. theodore beza in calvin's pulpit tore his grim black gown, and vowed it was the star that led the magi. it had now returned to mark the world's end and the judgment day. then, in this hubbub, dancey told the king of denmark, "there is one who knows the truth-your subject tycho brahe, who, night by night, watched and recorded all that truth could see. it would bring honour to all denmark, sire, if tycho could forget his rank awhile, and print these great discoveries in a book, for all the world to read." so tycho brahe received a letter in the king's own hand, urging him, "truth is the one pure fountain-head of all nobility. pray forget your rank." his noble kinsmen echoed, "if you wish to please his majesty and ourselves, forget your rank." "i will," said tycho brahe; "your reasoning has convinced me. i will print my book, '_de nova stella._' and to prove all you have said concerning temporal rank and this eternal truth you love so well, i marry, to-day,"--they foamed, but all their mouths were stopped and stuffed and sealed with their own words,-"i marry to-day my own true love, christine." v they thought him a magician, tycho brahe. perhaps he was. there's magic all around us in rocks and trees, and in the minds of men, deep hidden springs of magic. he that strikes the rock aright, may find them where he will. and tycho tasted happiness in his hour. there was a prince in denmark in those days; and, when he heard how other kings desired the secrets of this new astrology, he said, "this man, in after years, will bring glory to denmark, honour to her prince. he is a dane. give him this isle of wheen, and let him make his great discoveries there. let him have gold to buy his instruments, and build his house and his observatory." so tycho set this island where he lived whispering with wizardry; and, in its heart, he lighted that strange lanthorn of the law, and built himself that wonder of the world, uraniborg, a fortress for the truth, a city of the heavens. around it ran a mighty rampart twenty-two feet high, and twenty feet in thickness at the base. its angles pointed north, south, east and west, with gates and turrets; and, within this wall, were fruitful orchards, apple, and cherry, and pear; and, sheltered in their midst from all but sun, a garden, warm and busy with singing bees. there, many an hour, his flaxen-haired christine, sang to her child, her first-born, magdalen, or watched her playing, a flower among the flowers. dark in the centre of that zone of bliss arose the magic towers of tycho brahe. two of them had great windows in their roofs opening upon the sky where'er he willed, and under these observatories he made a library of many a golden book; poets and sages of old greece and rome, and many a mellow legend, many a dream of dawning truth in egypt, or the dusk of araby. under all of these he made a subterranean crypt for alchemy, with sixteen furnaces; and, under this, he sank a well, so deep, that jeppe declared he had tapped the central fountains of the world, and drew his magic from those cold clear springs. this was the very well, said jeppe, the dwarf, where truth was hidden; but, by tycho brahe and his weird skill, the magic water flowed, through pipes, uphill, to all the house above: the kitchen where his cooks could broil a trout for sages or prepare a feast for kings; the garrets for the students in the roof; the guest-rooms, and the red room to the north, the study and the blue room to the south; the small octagonal yellow room that held the sunlight like a jewel all day long, and magdalen, with her happy dreams, at night; then, facing to the west, one long green room, the ceiling painted like the bower of eve with flowers and leaves, the windows opening wide through which christine and tycho brahe at dawn could see the white sails drifting on the sound like petals from their orchard. to the north, he built a printing house for noble books, poems, and those deep legends of the sky, still to be born at his uraniborg. beyond the rampart to the north arose a workshop for his instruments. to the south a low thatched farm-house rambled round a yard alive with clucking hens; and, further yet to southward on another hill, he made a great house for his larger instruments, and called it stiernborg, mountain of the stars. and, on his towers and turrets, tycho set statues with golden verses in the praise of famous men, the bearers of the torch, from ptolemy to the new copernicus. then, in that storm-proof mountain of the stars, he set in all their splendour of new-made brass his armouries for the assault of heaven,-circles in azimuth, armillary spheres, revolving zodiacs with great brazen rings; quadrants of solid brass, ten cubits broad, brass parallactic rules, made to revolve in azimuth; clocks with wheels; an astrolabe; and that large globe strengthened by oaken beams he made at augsburg. all his gold he spent; but denmark had a prince in those great days; and, in his brain, the dreams of tycho brahe kindled a thirst for glory. so he made tycho the lord of sundry lands and rents, and keeper of the chapel where the kings of oldenburg were buried; for he said "to whom could all these kings entrust their bones more fitly than to him who read the stars, and though a mortal, knew immortal laws; and paced, at night, the silent halls of heaven." vi he was a great magician, tycho brahe. there, on his island, for a score of years, he watched the skies, recording star on star, for future ages, and, by patient toil, perfected his great tables of the sun, the moon, the planets. there, too happy far for any history, sons and daughters rose, a little clan of love, around christine; and tycho thought, when i am dead, my sons will rule and work in my uraniborg. and yet a doubt would trouble him, for he knew the children of christine would still be held ignoble, by the world. disciples came, young-eyed and swift, the bearers of the torch from many a city to uraniborg, and tycho brahe received them like a king, and bade them light their torches at his fire. the king of scotland came, with all his court, and dwelt eight days in tycho brahe's domain, asking him many a riddle, deep and dark, whose answer, none the less, a king should know. what boots it on this earth to be a king, to rule a part of earth, and not to know the worth of his own realm, whether he rule as god's vice-gerent, and his realm be still the centre of the centre of all worlds; or whether, as copernicus proclaimed, this earth itself be moving, a lost grain of dust among the innumerable stars? for this would dwarf all glory but the soul, in king or peasant, that can hail the truth, though truth should slay it. so to tycho brahe, the king became a subject for eight days. but, in the crowded hall, when he had gone, jeppe raised his matted head, with a chuckle of glee, quiet as the gurgle of joy in a dark rock-pool, when the first ripple and wash of the first spring-tide flows bubbling under the dry sun-blackened fringe of seaweed, setting it all afloat again, in magical colours, like a merman's hair. "jeppe has a thought," the gay young students cried, thronging him round, for all believed that jeppe was fey, and had strange visions of the truth. "what is the thought, jeppe?" "i can think no thoughts," croaked jeppe. "but i have made myself a song." "silence," they cried, "for jeppe the nightingale! sing, jeppe!" and, wagging his great head to and fro before the fire, with deep dark eyes, he crooned: the song of jeppe "what!" said the king, "is earth a bird or bee? can this uncharted boundless realm of ours drone thro' the sky, with leagues of struggling sea, forests, and hills, and towns, and palace-towers?" "ay," said the dwarf, "i have watched from stiernborg's crown her far dark rim uplift against the sky; but, while earth soars, men say the stars go down; and, while earth sails, men say the stars go by." an elvish tale! ask jeppe, the dwarf! _he_ knows. that's why his eyes look fey; for, chuckling deep, heels over head amongst the stars he goes, as all men go; but most are sound asleep. king, saint, sage, even those that count it true, act as this miracle touched them not at all. they are borne, undizzied, thro' the rushing blue, and build their empires on a sky-tossed ball. then said the king, "if earth so lightly move, what of my realm? o, what shall now stand sure?" "naught," said the dwarf, "in all this world, but love. all else is dream-stuff and shall not endure. 'tis nearer now! our universe hath no centre, our shadowy earth and fleeting heavens no stay, but that deep inward realm which each can enter, even jeppe, the dwarf, by his own secret way." "where?" said the king, "o, where? i have not found it!" "here," said the dwarf, and music echoed "here." "this infinite circle hath no line to bound it; therefore that deep strange centre is everywhere. let the earth soar thro' heaven, that centre abideth; or plunge to the pit, his covenant still holds true. in the heart of a dying bird, the master hideth; in the soul of a king," said the dwarf, "and in _my_ soul, too." vii princes and courtiers came, a few to seek a little knowledge, many more to gape in wonder at tycho's gold and silver mask; or when they saw the beauty of his towers, envy and hate him for them. thus arose the small grey cloud upon the distant sky, that broke in storm at last. "beware," croaked jeppe, lifting his shaggy head beside the fire, when guests like these had gone, "master, beware!" and tycho of the frank blue eyes would laugh. even when he found witichius playing him false his anger, like a momentary breeze, died on the dreaming deep; for tycho brahe turned to a nobler riddle,--"have you thought," he asked his young disciples, "how the sea is moved to that strange rhythm we call the tides? he that can answer this shall have his name honoured among the bearers of the torch while pegasus flies above uraniborg. i was delayed three hours or more to-day by the neap-tide. the fishermen on the coast are never wrong. they time it by the moon. _post hoc_, perhaps, not _propter hoc_; and yet through all the changes of the sky and sea that old white clock of ours with the battered face does seem infallible. there's a love-song too, the sailors on the coast of sweden sing, i have often pondered it. your courtly poets upbraid the inconstant moon. but these men know the moon and sea are lovers, and they move in a most constant measure. hear the words and tell me, if you can, what silver chains bind them together." then, in a voice as low and rhythmical as the sea, he spoke that song: the shepherdess of the sea reproach not yet our sails' delay; you cannot see the shoaling bay, the banks of sand, the fretful bars, that ebb left naked to the stars. the sea's white shepherdess, the moon, shall lead us into harbour soon. dear, when you see her glory shine between your fragrant boughs of pine, know there is but one hour to wait before her hands unlock the gate, and the full flood of singing foam follow her lovely footsteps home. then waves like flocks of silver sheep come rustling inland from the deep, and into rambling valleys press behind their heavenly shepherdess. you cannot see them? lift your eyes and see their mistress in the skies. she rises with her silver bow. i feel the tide begin to flow; and every thought and hope and dream follow her call, and homeward stream. borne on the universal tide, the wanderer hastens to his bride. the sea's white shepherdess, the moon, shall lead him into harbour, soon. viii he was a great magician, tycho brahe, but not so great that he could read the heart or rule the hand of princes. when his friend king frederick died, the young prince christian reigned; and, round him, fool and knave made common cause against the magic that could pour their gold into a gulf of stars. this tycho brahe had grown too proud. he held them in contempt, so they believed; for, when he spoke, their thoughts crept at his feet like spaniels. junkerdom felt it was foolish, for he towered above it, and so it hated him. did he not spend gold that a fool could spend as quickly as he? were there not great estates bestowed upon him in wisdom's name, that from the dawn of time had been the natural right of junkerdom? and would he not bequeath them to his heirs, the children of christine, an unfree woman? "why you, sire, even you," they told the king, "he has made a laughing-stock. that horoscope he read for you, the night when you were born, printed, and bound it in green velvet, too,-read it the whole world laughs at it. he said that venus was the star that ruled your fate, and venus would destroy you. tycho brahe inspired your royal father with the fear that kept your youth so long in leading-strings, the fear that every pretty hedgerow flower would be your circe. so he thought to avenge our mockery of this peasant-girl christine, to whom, indeed, he plays the faithful swine, knowing full well his gold and silver nose would never win another." thus the sky darkened above uraniborg, and those who dwelt within it, till one evil day, one seeming happy day, when tycho marked the seven-hundredth star upon his chart, two pompous officers from walchendorp, the chancellor, knocked at tycho's eastern gate. "we are sent," they said, "to see and to report what use you make of these estates of yours. your alchemy has turned more gold to lead than denmark can approve. the uses now! show us the uses of this work of yours." then tycho showed his tables of the stars, seven hundred stars, each noted in its place with exquisite precision, the result of watching heaven for five-and-twenty years. "and is this all?" they said. they sought to invent some ground for damning him. the truth alone would serve them, as it seemed. for these were men who could not understand. "not all, i hope," said tycho, "for i think, before i die, i shall have marked a thousand." "to what end? when shall we reap the fruits of all this toil? show us its uses." "in the time to come," said tycho brahe, "perhaps a hundred years, perhaps a thousand, when our own poor names are quite forgotten, and our kingdoms dust, on one sure certain day, the torch-bearers will, at some point of contact, see a light moving upon this chaos. though our eyes be shut for ever in an iron sleep, their eyes shall see the kingdom of the law, our undiscovered cosmos. they shall see it-a new creation rising from the deep, beautiful, whole. we are like men that hear disjointed notes of some supernal choir. year after year, we patiently record all we can gather. in that far-off time, a people that we have not known shall hear them, moving like music to a single end." they could not understand: this life that sought only to bear the torch and hand it on; and so they made report that all the dreams of tycho brahe were fruitless; perilous, too, since he avowed that any fruit they bore would fall, in distant years, to alien hands. little by little, walchendorp withdrew his rents from tycho brahe, accusing him of gross neglects. the chapel at roskilde was falling into ruin. tycho brahe was keeper of the bones of oldenburg. he must rebuild the chapel. all the gifts that frederick gave to help him in his task, were turned to stumbling-blocks; till, one dark day, he called his young disciples round him there, and in that mellow library of dreams, lit by the dying sunset, poured his heart and mind before them, bidding them farewell. through the wide-open windows as he spoke they heard the sorrowful whisper of the sea ebbing and flowing around uraniborg. "an end has come," he said, "to all we planned. uraniborg has drained her treasury dry. your alma mater now must close her gates on you, her guests; on me; and, worst of all, on one most dear, who made this place my home. for you are young, your homes are all to win, and you would all have gone your separate ways in a brief while; and, though i think you love your college of the skies, it could not mean all that it meant to those who called it 'home.' you that have worked with me, for one brief year, will never quite forget uraniborg. this room, the sunset gilding all those books, the star-charts and that old celestial globe, the long bright evenings by the winter fire, of tycho brahe were fruitless; perilous the talk that opened heaven, the songs you sung, yes, even, i think, the tricks you played with jeppe, will somehow, when yourselves are growing old, be hallowed into beauty, touched with tears, for you will wish they might be yours again. these have been mine for five-and-twenty years, and more than these,--the work, the dreams i shared with you, and others here. my heart will break to leave them. but the appointed time has come as it must come to all men. you and i have watched too many constant stars to dream that heaven or earth, the destinies of men or nations, are the sport of chance. an end comes to us all through blindness, age, or death. if mine must come in exile, it stall find me bearing the torch as far as i can bear it, until i fall at the feet of the young runner, who takes it from me, and carries it out of sight, into the great new age i shall not know, into the great new realms i must not tread. come, then, swift-footed, let me see you stand waiting before me, crowned with youth and joy, at the next turning. take it from my hand, for i am almost ready now to fall. something i have achieved, yes, though i say it, i have not loitered on that fiery way. and if i front the judgment of the wise in centuries to come, with more of dread than my destroyers, it is because this work will be of use, remembered and appraised, when all their hate is dead. i say the work, not the blind rumour, the glory or fame of it. these observations of seven hundred stars are little enough in sight of those great hosts which nightly wheel around us, though i hope, yes, i still hope, in some more generous land to make my thousand up before i die. little enough, i know,--a midget's work! the men that follow me, with more delicate art may add their tens of thousands; yet my sum will save them just that five-and-twenty years of patience, bring them sooner to their goal, that kingdom of the law i shall not see. we are on the verge of great discoveries. i feel them as a dreamer feels the dawn before his eyes are opened. many of you will see them. in that day you will recall this, our last meeting at uraniborg, and how i told you that this work of ours would lead to victories for the coming age. the victors may forget us. what of that? theirs be the palms, the shouting, and the praise. ours be the fathers' glory in the sons. ours the delight of giving, the deep joy of labouring, on the cliff's face, all night long, cutting them foot-holes in the solid rock, whereby they climb so gaily to the heights, and gaze upon their new-discovered worlds. you will not find me there. when you descend, look for me in the darkness at the foot of those high cliffs, under the drifted leaves. that's where we hide at last, we pioneers, for we are very proud, and must be sought before the world can find us, in our graves. there have been compensations. i have seen in darkness, more perhaps than eyes can see when sunlight blinds them on the mountain-tops; guessed at a glory past our mortal range, and only mine because the night was mine. of those three systems of the universe, the ptolemaic, held by all the schools, may yet be proven false. we yet may find this earth of ours is not the sovran lord of all those wheeling spheres. ourselves have marked movements among the planets that forbid acceptance of it wholly. some of these are moving round the sun, if we can trust our years of watching. there are stranger dreams. this radical, copernicus, the priest, of whom i often talked with you, declares ail of these movements can be reconciled, if--a hypothesis only--we should take the sun itself for centre, and assume that this huge earth, so 'stablished, so secure in its foundations, is a planet also, and moves around the sun. i cannot think it. this leap of thought is yet too great for me. i have no doubt that ptolemy was wrong. some of his planets move around the sun. copernicus is nearer to the truth in some things. but the planets we have watched still wander from the course that he assigned. therefore, my system, which includes the best of both, i hold may yet be proven true. this earth of ours, as jeppe declared one day, so simply that we laughed, is 'much too big to move,' so let it be the centre still, and let the planets move around their sun; but let the sun with all its planets move around our central earth. this at the least accords with all we know, and saves mankind from that enormous plunge into the night; saves them from voyaging for ten thousand years through boundless darkness without sight of land; saves them from all that agony of loss, as one by one the beacon-fires of faith are drowned in blackness. i beseech you, then, let me be proven wrong, before you take that darkness lightly. if at last you find the proven facts against me, take the plunge. launch out into that darkness. let the lamps of heaven, the glowing hearth-fires that we knew die out behind you, while the freshening wind blows on your brows, and overhead you see the stars of truth that lead you from your home. i love this island,--every little glen, hazel-wood, brook, and fish-pond; every bough and blossom in that garden; and i hoped to die here. but it is not chance, i know, that sends me wandering through the world again. my use perhaps is ended; and the power that made me, breaks me." as he spoke, they saw the tears upon his face. he bowed his head and left them silent in the darkened room. they saw his face no more. the self-same hour, tycho, christine, and all their children, left their island-home for even in their ship they took a few of the smaller instruments, and that most precious record of the stars, his legacy to the future. into the night they vanished, leaving on the ghostly cliffs only one dark, distorted, dog-like shape to watch them, sobbing, under its matted hair, "master, have you forgotten jeppe, your dwarf?" ix he was a great magician, tycho brahe, and yet his magic, under changing skies, could never change his heart, or touch the hills of those far countries with the tints of home. and, after many a month of wandering, he came to prague; and, though with open hands rodolphe received him, like an exiled king, a new aeneas, exiled for the truth (for so they called him), none could heal the wounds that bled within, or lull his grief to sleep with that familiar whisper of the waves, ebbing and flowing around uraniborg. doggedly still he laboured; point by point, crept on, with aching heart and burning brain, until his table of the stars had reached the thousand that he hoped, to crown his toil. but christine heard him murmuring in the night, "the work, the work! not to have lived in vain! into whose hands can i entrust it all? i thought to find him standing by the way, waiting to seize the splendour from my hand, the swift, young-eyed runner with the torch. let me not live in vain, let me not fall before i yield it to the appointed soul." and yet the power that made and broke him heard: for, on a certain day, to tycho came another exile, guided through the dark of europe by the starlight in his eyes, or that invisible hand which guides the world. he asked him, as the runner with the torch alone could ask, asked as a natural right for tycho's hard-won life-work, those results, his tables of the stars. he gave his name almost as one who told him, _it is i;_ and yet unconscious that he told; a name not famous yet, though truth had marked him out already, by his exile, as her own,-the name of johann kepler. "it was strange," wrote kepler, not long after, "for i asked unheard-of things, and yet he gave them to me as if i were his son. when first i saw him, we seemed to have known each other years ago in some forgotten world. i could not guess that tycho brahe was dying. he was quick of temper, and we quarrelled now and then, only to find ourselves more closely bound than ever. i believe that tycho died simply of heartache for his native land. for though he always met me with a smile, or jest upon his lips, he could not sleep or work, and often unawares i caught odd little whispered phrases on his lips as if he talked to himself, in a kind of dream. yet i believe the clouds dispersed a little around his death-bed, and with that strange joy which comes in death, he saw the unchanging stars. christine was there. she held him in her arms. i think, too, that he knew his work was safe. an hour before he died, he smiled at me, and whispered,--what he meant i hardly know-perhaps a broken echo from the past, a fragment of some old familiar thought, and yet i seemed to know. it haunts me still: _'come then, swift-footed, let me see you stand, waiting before me, crowned with youth and joy; this is the turning. take it from my hand. for i am ready, ready now, to fall.'"_ iii kepler john kepler, from the chimney corner, watched his wife susannah, with her sleeves rolled back making a salad in a big blue bowl. the thick tufts of his black rebellious hair brushed into sleek submission; his trim beard snug as the soft round body of a thrush between the white wings of his fan-shaped ruff (his best, with the fine lace border) spoke of guests expected; and his quick grey humorous eyes, his firm red whimsical pleasure-loving mouth, and all those elvish twinklings of his face, were lit with eagerness. only between his brows, perplexed beneath that subtle load of dreams, two delicate shadows brooded. "what does it mean? sir henry wotton's letter breathed a hint that italy is prohibiting my book," he muttered. "then, if austria damns it too, susannah mine, we may be forced to choose between the truth and exile. when he comes, he'll tell me more. ambassadors, i suppose, can only write in cipher, while our world is steered to heaven by murderers and thieves; but, if he'd wrapped his friendly warnings up in a verse or two, i might have done more work these last three days, eh, sue?" "look, john," said she, "what beautiful hearts of lettuce! tell me now how shall i mix it? will your english guest turn up his nose at dandelion leaves as crisp and young as these? they've just the tang of bitterness in their milk that gives a relish and makes all sweet; and that's philosophy, john. now--these spring onions! would his excellency like sugared rose-leaves better?" "he's a poet, not an ambassador only, so i think he'll like a cottage salad." "a poet, john! i hate their arrogant little insect ways! i'll put a toadstool in." "poets, dear heart, can be divided into two clear kinds,-one that, by virtue of a half-grown brain, lives in a silly world of his own making, a bubble, blown by himself, in which he flits and dizzily bombinates, chanting 'i, i, i,' for there is nothing in the heavens above or the earth, or hell beneath, but goes to swell his personal pronoun. bring him some dreadful news his dearest friend is burned to death,--you'll see the monstrous insect strike an attitude and shape himself into one capital i, a rubric, with red eyes. you'll see him use the coffin for his pedestal, hear him mouth his 'i, i, i' instructing haggard grief concerning his odd ego. does he chirp of love, it's 'i, i, i' narcissus, love, myself, narcissus, imaged in those eyes; for all the love-notes that he sounds are made after the fashion of passionate grasshoppers, by grating one hind-leg across another. nor does he learn to sound that mellower 'you,' until his bubble bursts and leaves him drowned, an insect in a soap-sud. but there's another kind, whose mind still moves in vital concord with the soul of things; so that it thinks in music, and its thoughts pulse into natural song. a separate voice, and yet caught up by the surrounding choirs, there, in the harmonies of the universe, losing himself, he saves his soul alive." "john, i'm afraid!"- "afraid of what, susannah?"-"afraid to put those ducklings on to roast. your friend may miss his road; and, if he's late, my little part of the music will be spoiled."-"he won't, susannah. bad poets are always late. good poets, at times, delay a note or two; but all the great are punctual as the sun. what's that? he's early! that's his knock, i think!"-"the lord have mercy, john, there's nothing ready! take him into your study and talk to him, talk hard. he's come an hour before his time; and i've to change my dress. i'll into the kitchen!" then, in a moment, all the cottage rang with greetings; hand grasped hand; his excellency forgot the careful prologue he'd prepared, and made an end of mystery. he had brought a message from his wisdom-loving king who, hearing of new menaces to the light in europe, urged the illustrious kepler now to make his home in england. there, his thought and speech would both be free. "my friend," said wotton, "i have moved in those old strongholds of the night, and heard strange mutterings. it is not many years since bruno burned. there's trouble brewing too, for one you know, i think,--the florentine who made that curious optic tube."- "you mean the man at padua, galileo?"- "yes." "they will not dare or need. proof or disproof rests with their eyes."- "kepler, have you not heard of those who, fifteen hundred years ago, had eyes and would not see? eyes quickly close when souls prefer the dark."-"so be it. other and younger eyes will see. perhaps that's why god gave the young a spice of devilry. they'll go look, while elders gasp; and, when the devil and truth go hand in hand, god help their enemies. you will send my thanks, my grateful thanks, sir henry, to your king. to-day i cannot answer you. i must think. it would be very difficult my wife would find it hard to leave her native land. say nothing yet before her." then, to hide their secret from susannah, kepler poured his mind out, and the world's dead branches bloomed. for, when he talked, another spring began to which our may was winter; and, in the boughs of his delicious thoughts, like feathered choirs, bits of old rhyme, scraps from the sabine farm, celestial phrases from the shepherd king, and fluttering morsels from catullus sang. much was fantastic. all was touched with light that only genius knows to steal from heaven. he spoke of poetry, as the "flowering time of knowledge," called it "thought in passionate tune with those great rhythms that steer the moon and sun; thought in such concord with the soul of things that it can only move, like tides and stars, and man's own beating heart, and the wings of birds, in law, whose service only sets them free." therefore it often leaps to the truth we seek, clasping it, as a lover clasps his bride in darkness, ere the sage can light his lamp. and so, in music, men might find the road to truth, at many a point, where sages grope. one day, a greater plato would arise to write a new philosophy, he said, showing how music is the golden clue to all the windings of the world's dark maze. himself had used it, partly proved it, too, in his own book,--_the harmonies of the world._ 'all that the years discover points one way to this great ordered harmony," he said, "revealed on earth by music. planets move in subtle accord like notes of one great song audible only to the artificer, the eternal artist. there's no grief, no pain, but music--follow it simply as a clue, a microcosmic pattern of the whole-can show you, somewhere in its golden scheme, the use of all such discords; and, at last, their exquisite solution. then darkness breaks into diviner light, love's agony climbs through death to life, and evil builds up heaven. have you not heard, in some great symphony, those golden mathematics making clear the victory of the soul? have you not heard the very heavens opening? do those fools who thought me an infidel then, still smile at me for trying to read the stars in terms of song, discern their orbits, measure their distances, by musical proportions? let them smile, my folly at least revealed those three great laws; gave me the golden vases of the egyptians, to set in the great new temple of my god beyond the bounds of egypt. they will forget my methods, doubtless, as the years go by, and the world's wisdom shuts its music out. the dust will gather on all my harmonies; or scholars turn my pages listlessly, glance at the musical phrases, and pass on, not troubling even to read one latin page. yet they'll accept those great results as mine. i call them mine. how can i help exulting, who climbed my ladder of music to the skies and found, by accident, let them call it so, or by the inspiration of that power which built his world of music, those three laws:-first, how the speed of planets round the sun bears a proportion, beautifully precise as music, to their silver distances; next, that although they seem to swerve aside from those plain circles of old copernicus their paths were not less rhythmical and exact, but followed always that most exquisite curve in its most perfect form, the pure ellipse; third, that although their speed from point to point appeared to change, their radii always moved through equal fields of space in equal times. was this my infidelity, was this less full of beauty, less divine in truth, than their dull chaos? you, the poet will know how, as those dark perplexities grew clear, and old anomalous discords changed to song, my whole soul bowed and cried, _almighty god these are thy thoughts, i am thinking after thee!_ i hope that tycho knows. i owed so much to tycho brahe; for it was he who built the towers from which i hailed those three great laws. how strange and far away it all seems now. the thistles grow upon that little isle where tycho's great uraniborg once was. yet, for a few sad years, before it fell into decay and ruin, there was one who crept about its crumbling corridors, and lit the fire of memory on its hearth."-wotton looked quickly up, "i think i have heard something of that. you mean poor jeppe, his dwarf. fynes moryson, at the mermaid inn one night showed a most curious manuscript, a scrawl on yellow parchment, crusted here and there with sea-salt, or the salt of those thick tears creatures like jeppe, the crooked dwarf, could weep. it had been found, clasped in a crooked hand, under the cliffs of wheen, a crooked hand that many a time had beckoned to passing ships, hoping to find some voyager who would take a letter to its master. the sailors laughed and jeered at him, till jeppe threw stones at them. and now jeppe, too, was dead, and one who knew fynes moryson, had found him, and brought home that curious crooked scrawl. fynes englished it out of its barbarous danish. thus it ran: 'master, have you forgotten jeppe, your dwarf, who used to lie beside the big log-fire and feed from your own hand? the hall is dark, there are no voices now,--only the wind and the sea-gulls crying round uraniborg. i too am crying, master, even i, because there is no fire upon the hearth, no light in any window. it is night, and all the faces that i knew are gone. master, i watched you leaving us. i saw the white sails dwindling into sea-gull's wings, then melting into foam, and all was dark. i lay among the wild flowers on the cliff and dug my nails into the stiff white chalk and called you, tycho brahe. you did not hear; but gulls and jackdaws, wheeling round my head, mocked me with _tycho brahe_, and _tycho brahe_! you were a great magician, tycho brahe; and, now that they have driven you away, i, that am only jeppe,--the crooked dwarf, you used to laugh at for his matted hair, and head too big and heavy--take your pen here in your study. i will write it down and send it by a sailor to the king of scotland, and who knows, the mouse that gnawed the lion free, may save you, tycho brahe.'" "he is free now," said kepler, "had he lived he would have sent for jeppe to join him there at prague. but death forestalled him, and your king. the years in which he watched that planet mars, his patient notes and records, all were mine; and, mark you, had he clipped or trimmed one fact by even a hair's-breadth, so that his results made a pure circle of that planet's path it might have baffled us for an age and drowned all our new light in darkness. but he held to what he saw. he might so easily, so comfortably have said, 'my instruments are crude and fallible. in so fine a point eyes may have erred, too. why not acquiesce? why mar the tune, why dislocate a world, for one slight clash of seeming fact with faith?' but no, though stars might swerve, he held his course, recording only what his eyes could see until death closed them. then, to his results, i added mine and saw, in one wild gleam, strange as the light of day to one born blind, a subtler concord ruling them and heard profounder tones of harmony resolve those broken melodies into song again."-"faintly and far away, i, too, have seen in music, and in verse, that golden clue whereof you speak," said wotton. "in all true song, there is a hidden logic. even the rhyme that, in bad poets, wrings the neck of thought, is like a subtle calculus to the true, an instrument of discovery. it reveals new harmonies, new analogies. it links far things and near, not in unnatural chains, but in those true accords which still escape the plodding reason, yet unify the world. i caught some glimpses of this mystic power in verses of your own, that elegy on tycho, and that great quatrain of yours-i cannot quite recall the latin words, but made it roughly mine in words like these: _'i know that i am dust, and daily die; yet, as i trace those rhythmic spheres at night, i stand before the thunderer's throne on high and feast on nectar in the halls of light.'_ my version lacks the glory of your lines but..." "mine too was a version," kepler laughed, "turned into latin from old ptolemy's greek; for, even in verse, half of the joy, i think, is just to pass the torch from hand to hand an undimmed splendour. but, last night, i tried some music all my own. i had a dream that i was wandering in some distant world. i have often dreamed it once it was the moon. i wrote that down in prose. when i am dead, it may be printed. this was a fairer dream: for i was walking in a far-off spring upon the planet, venus. only verse could spread true wings for that delicious world; and so i wrote it--for no eyes but mine, or 'twould be seized on, doubtless, as fresh proof of poor old kepler's madness."- "let me hear, madman to madman; for i, too, write verse." then kepler, in a rhythmic murmur, breathed his rich enchanted memories of that dream: "beauty burned before me swinging a lanthorn through that fragrant night. i followed a distant singing, and a dreaming light how she led me, i cannot tell to that strange world afar, nor how i walked, in that wild glen upon the sunset star. winged creatures floated under those rose-red boughs of violet bloom, with delicate forms unknown on earth 'twixt irised plume and plume; human-hearted, angel-eyed, and crowned with unknown flowers; for nothing in that enchanted world followed the way of ours. only i saw that beauty, on hesper, as on earth, still held command; and though, as one in slumber, i roamed that radiant land, with all these earth-born senses sealed to what the hesperians knew, the faithful lanthorn of her law was mine on hesper too. then, half at home with wonder, i saw strange flocks of flowers like birds take flight; great trees that burned like opals to lure their loves at night; dark beings that could move in realms no dream of ours has known. till these became as common things as men account their own. yet, when that lanthorn led me back to the world where once i thought me wise; i saw, on this my planet, what souls, with awful eyes. hardly i dared to walk her fields as in that strange re-birth i looked on those wild miracles the birds and flowers of earth." silence a moment held them, loth to break the spell of that strange dream, "one proof the more" said wotton at last, "that songs can mount and fly to truth; for this fantastic vision of yours of life in other spheres, awakes in me, either that slumbering knowledge of socrates, or some strange premonition that the years will prove it true. this music leads us far from all our creeds, except that faith in law. your quest for knowledge--how it rests on that! how sure the soul is that if truth destroy the temple, in three days the truth will build a nobler temple; and that order reigns in all things. even your atheist builds his doubt on that strange faith; destroys his heaven and god in absolute faith that his own thought is true to law, god's lanthorn to our stumbling feet; and so, despite himself, he worships god, for where true souls are, there are god and heaven."-"it is an ancient wisdom. long ago," said kepler, "under the glittering eastern sky, the shepherd king looked up at those great stars, those ordered hosts, and cried _caeli narrant gloriam dei!_ though there be some to-day who'd ape lucretius, and believe themselves epicureans, little they know of him who, even in utter darkness, bowed his head, to something nobler than the gods of rome reigning beyond the darkness. they accept the law, the music of these ordered worlds; and straight deny the law's first postulate, that out of nothingness nothing can be born, nor greater things from less. can music rise by chance from chaos, as they said that star in serpentarius rose? i told them, then, that when i was a boy, with time to spare, i played at anagrams. out of my latin name _johannes keplerus_ came that sinister phrase _serpens in akuleo_. struck by this, i tried again, but trusted it to chance. i took some playing cards, and wrote on each one letter of my name. then i began to shuffle them; and, at every shuffle, i read the letters, in their order, as they came, to see what meaning chance might give to them. wotton, the gods and goddesses must have laughed to see the weeks i lost in studying chance; for had i scattered those cards into the black epicurean eternity, i'll swear they'd still be playing at leap-frog in the dark, and show no glimmer of sense. and yet--to hear those wittols talk, you'd think you'd but to mix a bushel of good greek letters in a sack and shake them roundly for an age or so, to pour the odyssey out. at last, i told, those disputants what my wife had said. one night when i was tired and all my mind a-dust with pondering on their atoms, i was called to supper, and she placed before me there a most delicious salad. 'it would appear,' i thought aloud, 'that if these pewter dishes, green hearts of lettuce, tarragon, slips of thyme, slices of hard boiled egg, and grains of salt. with drops of water, vinegar and oil, had in a bottomless gulf been flying about from all eternity, one sure certain day the sweet invisible hand of happy chance would serve them as a salad.' 'likely enough,' my wife replied, 'but not so good as mine, nor so well dressed.'" they laughed. susannah's voice broke in, "i've made a better one. the receipt came from the _golden lion_. i have dished ducklings and peas and all. come, john, say grace." iv galileo i (_celeste, in the convent at arcetri, writes to her old lover at rome._) my friend, my dearest friend, my own dear love, i, who am dead to love, and see around me the funeral tapers lighted, send this cry out of my heart to yours, before the end. you told me once you would endure the rack to save my heart one pang. o, save it now! last night there came a dreadful word from rome for my dear lord and father, summoning him before the inquisitors there, to take his trial at threescore years and ten. there is a threat of torture, if his lips will not deny the truth his eyes have seen. you know my father, you know me, too. you never will believe that he and i are enemies of the faith. could i, who put away all earthly love, deny the cross to which i nailed this flesh? could he, who, on the night when all those heavens opened above us, with their circling worlds, knelt with me, crushed beneath that weight of glory, forget the maker of that glory now? you'll not believe it. neither would the church, had not his enemies poisoned all the springs and fountain-heads of truth. it is not rome that summons him, but magini, sizy, scheiner, lorini, all the blind, pedantic crew that envy him his fame, and hate his works for dwarfing theirs. must such things always be when truth is born? only five nights ago we walked together, my father and i, here in the convent garden; and, as the dusk turned everything to dreams, we dreamed together of his work well done and happiness to be. we did not dream that even then, muttering above his book, his enemies, those enemies whom the truth stings into hate, were plotting to destroy him. yet something shadowed him. i recall his words-"the grapes are ripening. see, celeste, how black and heavy. we shall have good wine this year,"-"yes, all grows ripe," i said, "your life-work, too, dear father. are you happy now to know your book is printed, and the new world born?" he shook his head, a little sadly, i thought. "autumn's too full of endings. fruits grow ripe and fall, and then comes winter." "not for you! never," i said, "for those who write their names in heaven. think, father, through all ages now no one can ever watch that starry sky without remembering you. your fame ..." and there he stopped me, laid his hand upon my arm, and standing in the darkness with dead leaves drifting around him, and his bare grey head bowed in complete humility, his voice shaken and low, he said like one in prayer, "celeste, beware of that. say truth, not fame. if there be any happiness on earth, it springs from truth alone, the truth we live in act and thought. i have looked up there and seen too many worlds to talk of fame on earth. fame, on this grain of dust among the stars, the trumpet of a gnat that thinks to halt the great sun-clusters moving on their way in silence! yes, that's fame, but truth, celeste, truth and its laws are constant, even up there; that's where one man may face and fight the world. his weakness turns to strength. he is made one with universal forces, and he holds the password to eternity. gate after gate swings back through all the heavens. no sentry halts him, and no flaming sword. say truth, celeste, not fame." "no, for i'll say a better word," i told him. "i'll say love." he took my face between his hands and said-his face all dark between me and the stars-"what's love, celeste, but this dear face of truth upturned to heaven." he left me, and i heard, some twelve hours later, that this man whose soul was dedicate to truth, was threatened now with torture, if his lips did not deny the truth he loved. i tell you all these things because to help him, you must understand him; and even you may doubt him, if you hear only those plausible outside witnesses who never heard his heart-beats as have i. so let me tell you all--his quest for truth, and how this hate began. even from the first, he made his enemies of those almost-minds who chanced upon some new thing in the dark and could not see its meaning, for he saw, always, the law illumining it within. so when he heard of that strange optic-glass which brought the distance near, he thought it out by reason, where that other hit upon it only by chance. he made his telescope; and o, how vividly that day comes back, when in their gorgeous robes the senate stood beside him on that high venetian tower, scanning the bare blue sea that showed no speck of sail. then, one by one, he bade them look; and one by one they gasped, "a miracle." brown sails and red, a fleet of fishing boats, see how the bright foam bursts around their bows! see how the bare-legged sailors walk the decks! then, quickly looking up, as if to catch the vision, ere it tricked them, all they saw was empty sea again. many believed that all was trickery, but he bade them note the colours of the boats, and count their sails. then, in a little while, the naked eye saw on the sky-line certain specks that grew, took form and colour; and, within an hour, their magic fleet came foaming into port. whereat old senators, wagging their white beards, and plucking at golden chains with stiff old claws too feeble for the sword-hilt, squeaked at once: "this glass will give us great advantages in time of war." war, war, o god of love, even amidst their wonder at thy world, dazed with new beauty, gifted with new powers, these old men dreamed of blood. this was the thought to which all else must pander, if he hoped even for one hour to see those dull eyes blaze at his discoveries. "wolves," he called them, "wolves"; and yet he humoured them. he stooped to them. promised them more advantages, and talked as elders do to children. you may call it weakness, and yet could any man do more, alone, against a world, with such a trust to guard for future ages? all his life he has had some weanling truth to guard, has fought desperately to defend it, taking cover wherever he could, behind old fallen trees of superstition, or ruins of old thought. he has read horoscopes to keep his work among the stars in favour with his prince, i tell you this that you may understand what seems inconstant in him. it may be that he was wrong in these things, and must pay a dreadful penalty. but you must explore his mind's great ranges, plains and lonely peaks before you know him, as i know him now. how could he talk to children, but in words that children understand? have not some said that god himself has made his glory dark for men to bear it. in his human sphere my father has done this. war was the dream that filmed those old men's eyes. they did not hear my father, when he hinted at his hope of opening up the heavens for mankind with that new power of bringing far things near. my heart burned as i heard him; but they blinked like owls at noonday. then i saw him turn, desperately, to humour them, from thoughts of heaven to thoughts of warfare. late that night my own dear lord and father came to me and whispered, with a glory in his face as one who has looked on things too beautiful to breathe aloud, "come out, celeste, and see a miracle." i followed him. he showed me, looking along his outstretched hand, a star, a point of light above our olive-trees. it was the star called jupiter. and then he bade me look again, but through his glass. i feared to look at first, lest i should see some wonder never meant for mortal eyes. he too, had felt the same, not fear, but awe, as if his hand were laid upon the veil between this world and heaven. then . . . i, too, saw, small as the smallest bead of mist that clings to a spider's thread at dawn, the floating disk of what had been a star, a planet now, and near it, with no disk that eyes could see, four needle-points of light, unseen before. "the moons of jupiter," he whispered low, "i have watched them as they moved, from night to night; a system like our own, although the world their fourfold lights and shadows make so strange must--as i think--be mightier than we dreamed, a titan planet. earth begins to fade and dwindle; yes, the heavens are opening now. perhaps up there, this night, some lonely soul gazes at earth, watches our dawning moon, and wonders, as we wonder." in that dark we knelt together . . . very strange to see the vanity and fickleness of princes. before his enemies had provoked the wrath of rome against him, he had given the name of medicean stars to those four moons in honour of prince cosmo. this aroused the court of france to seek a lasting place upon the map of heaven. a letter came beseeching him to find another star even more brilliant, and to call it _henri_ after the reigning and most brilliant prince of france. they did not wish the family name of bourbon. this would dissipate the glory. no, they preferred his proper name of henri. we read it together in the garden here, weeping with laughter, never dreaming then that this, this, this, could stir the little hearts of men to envy. o, but afterwards, the blindness of the men who thought themselves his enemies. the men who never knew him, the men that had set up a thing of straw and called it by his name, and wished to burn their image and himself in one wild fire. men? were they men or children? they refused even to look through galileo's glass, lest seeing might persuade them. even that sage, that great aristotelian, julius libri, holding his breath there, like a fractious child until his cheeks grew purple, and the veins were bursting on his brow, swore he would die sooner than look. and that poor monstrous babe not long thereafter, kept his word and died, died of his own pent rage, as i have heard. whereat my lord and father shook his head and, smiling, somewhat sadly--oh, you know that smile of his, more deadly to the false than even his reasoning--murmured, _"libri, dead, who called the moons of jupiter absurd! he swore he would not look at them from earth, i hope he saw them on his way to heaven."_ welser in augsburg, clavius at rome, scoffed at the fabled moons of jupiter, it was a trick, they said. he had made a glass to fool the world with false appearances. perhaps the lens was flawed. perhaps his wits were wandering. anything rather than the truth which might disturb the mighty in their seat. "let galileo hold his own opinions. i, clavius, will hold mine." he wrote to kepler; "you, kepler, are the first, whose open mind and lofty genius could accept for truth the things which i have seen. with you for friend, the abuse of the multitude will not trouble me. jupiter stands in heaven and will stand, though all the sycophants bark at him. in pisa, florence, bologna, venice, padua, many have seen the moons. these witnesses are silent and uncertain. do you wonder? most of them could not, even when they saw them, distinguish mars from jupiter. shall we side with heraclitus or democritus? i think, my kepler, we will only laugh at this immeasurable stupidity. picture the leaders of our college here. a thousand times i have offered them the proof of their own eyes. they sleep here, like gorged snakes, refusing even to look at planets, moons, or telescope. they think philosophy is all in books, and that the truth is found neither in nature, nor the universe, but in comparing texts. how you would laugh had you but heard our first philosopher before the grand duke, trying to tear down and argue the new planets out of heaven, now by his own weird logic and closed eyes and now by magic spells." how could he help despising them a little? it's an error even for a giant to despise a midge; for, when the giant reels beneath some stroke of fate, the buzzing clouds will swoop upon him, cluster and feed upon his bleeding wounds, and do what midges can to sting him blind. these human midges have not missed their chance. they have missed no smallest spot upon that sun. my mother was not married--they have found-to my dear father. all his children, then, and doubtless all their thoughts are evil, too; but who that judged him ever sought to know whether, as evil sometimes wears the cloak of virtue, nobler virtue in this man might wear that outward semblance of a sin? yes, even you who love me, may believe these thoughts are born of my own tainted heart; and yet i write them, kneeling in my cell and whisper them to one who blesses me here, from his cross, upon the bare grey wall. so, if you love me, bless me also, you, by helping him. make plain to all you meet what part his enemies have played in this. how some one, somehow, altered the command laid on him all those years ago, by rome, so that it reads to-day as if he vowed never to think or breathe that this round earth moves with its sister-planets round the sun. 'tis true he promised not to write or speak as if this truth were 'stablished equally with god's eternal laws; and so he wrote his dialogues, reasoning for it, and against, and gave the last word to simplicio, saying that human reason must bow down before the power of god. and even this his enemies have twisted to a sneer against the pope, and cunningly declared simplicio to be urban. why, my friend, there were three dolphins on the titlepage, each with the tail of another in its mouth. the censor had not seen this, and they swore it held some hidden meaning. then they found the same three dolphins sprawled on all the books landini printed at his florence press. they tried another charge. i am not afraid of any truth that they can bring against him; but, o, my friend, i more than fear their lies. i do not fear the justice of our god; but i do fear the vanity of men; even of urban; not his holiness, but urban, the weak man, who may resent, and in resentment rush half-way to meet this cunning lie with credence. vanity! o, half the wrongs on earth arise from that! greed, and war's pomp, all envy, and most hate, are born of that; while one dear humble heart, beating with love for man, between two thieves, proves more than all his wounds and miracles our crucified to be the son of god. say that i long to see him; that my prayers knock at the gates of mercy, night and day. urge him to leave the judgment now with god and strive no more. if he be right, the stars fight for him in their courses. let him bow his poor, dishonoured, glorious, old grey head before this storm, and then come home to me. o, quickly, or i fear 'twill be too late; for i am dying. do not tell him this; but i must live to hold his hands again, and know that he is safe. i dare not leave him, helpless and half blind, half father and half child, to rack and cord. by all the christ within you, save him, you; and, though you may have ceased to love me now, one faithful shadow in your own last hour shall watch beside you till all shadows die, and heaven unfold to bless you where i failed. ii (_scheiner writes to castelli, after the trial._) what think you of your galileo now, your hero that like ajax should defy the lightning? yesterday i saw him stand trembling before our court of cardinals, trembling before the colour of their robes as sheep, before the slaughter, at the sight and smell of blood. his lips could hardly speak, and--mark you--neither rack, nor cord had touched him. out of the inquisition's five degrees of rigor: first, the public threat of torture; second, the repetition of the threat within the torture-chamber, where we show the instruments of torture to the accused; third, the undressing and the binding; fourth, laying him on the rack; then, fifth and last, torture, _territio realis_; out of these, your galileo reached the second only, when, clapping both his hands against his sides, he whined about a rupture that forbade these extreme courses. great heroic soul dropped like a cur into a sea of terror, he sank right under. then he came up gasping, ready to swear, deny, abjure, recant, anything, everything! foolish, weak, old man, who had been so proud of his discoveries, and dared to teach his betters. how we grinned to see him kneeling there and whispering, thus, through his white lips, bending his old grey head: _"i, galileo galilei, born a florentine, now seventy years of age, kneeling before you, having before mine eyes, and touching with my hands the holy gospels, swear that i always have believed, do now, and always will believe what holy church has held and preached and taught me to believe; and now, whereas i rightly am accused, of heresy, having falsely held the sun to be the centre of our universe, and also that this earth is not the centre, but moves; i most illogically desire completely to expunge this dark suspicion, so reasonably conceived. i now abjure, detest and curse these errors; and i swear that should i know another, friend or foe, holding the selfsame heresy as myself, i will denounce him to the inquisitor in whatsoever place i chance to be. so help me god, and these his holy gospels, which with my hands i touch!"_ you will observe his promise to denounce. beware, castelli! what think you of your galileo now? iii _(castelli writes, enclosing schemer's letter, to campanella.)_ what think i? this,--that he has laid his hands like samson on the pillars of our world, and one more trembling utterance such as this will overwhelm us all. o, campanella, you know that i am loyal to our faith, as galileo too has always been. you know that i believe, as he believes, in the one catholic apostolic church; yet there are many times when i could wish that some blind samson would indeed tear down all this proud temporal fabric, made with hands, and that, once more, we suffered with our lord, were persecuted, crucified with him. i tell you, campanella, on that day when galileo faced our cardinals, a veil was rent for me. there, in one flash, i saw the eternal tragedy, transformed into new terms. i saw the christ once more, before the court of pilate. peter there denied him once again; and, as for me, never has all my soul so humbly knelt to god in christ, as when that sad old man bowed his grey head, and knelt--at seventy years-to acquiesce, and shake the world with shame. _he shall not strive or cry_! strange, is it not, how nearly scheiner--even amidst his hate-quoted the prophets? do we think this world so greatly bettered, that the ancient cry, "_despised, rejected_," hails our god no more? iv (_celeste writes to her father in his imprisonment at siena_.) dear father, it will seem a thousand years until i see you home again and well. i would not have you doubt that all this time i have prayed for you continually. i saw a copy of your sentence. i was grieved; and yet it gladdened me, for i found a way to be of use, by taking on myself your penance. therefore, if you fail in this, if you forget it--and indeed, to save you the trouble of remembering it--your child will do it for you. ah, could she do more! how willingly would your celeste endure a straiter prison than she lives in now to set you free. "a prison," i have said; and yet, if you were here, 'twould not be so. when you were pent in rome, i used to say, "would he were at siena!" god fulfilled that wish. you are at siena; and i now say would he were at arcctri. so perhaps little by little, angels can be wooed each day, by some new prayer of mine or yours, to bring you wholly back to me, and save some few of the flying days that yet remain. you see, these other nuns have each their friend, their patron saint, their ever near _devoto_, to whom they tell their joys and griefs; but i have only you, dear father, and if you were only near me, i could want no more. your garden looks as if it missed your love. the unpruned branches lean against the wall to look for you. the walks run wild with flowers. even your watch-tower seems to wait for you; and, though the fruit is not so good this year (the vines were hurt by hail, i think, and thieves have climbed the wall too often for the pears), the crop of peas is good, and only waits your hand to gather it. in the dovecote, too, you'll find some plump young pigeons. we must make a feast for your return. in my small plot, here at the convent, better watched than yours, i raised a little harvest. with the price i got for it, i had three masses said for my dear father's sake. v _(galileo writes to his friend castelli, after his return to arcetri.) _ castelli, o castelli, she is dead. i found her driving death back with her soul till i should come. i could not even see her face.--these useless eyes had spent their power on distant worlds, and lost that last faint look of love on earth. i am in the dark, castelli, utterly and irreparably blind. the universe which once these outworn eyes enlarged so far beyond its ancient bounds is henceforth shrunk into that narrow space which i myself inhabit. yet i found even in the dark, her tears against my face, her thin soft childish arms around my neck, and her voice whispering ... love, undying love; asking me, at this last, to tell her true, if we should meet again. her trust in me had shaken her faith in what my judges held; and, as i felt her fingers clutch my hand, like a child drowning, "tell me the truth," she said, "before i lose the light of your dear face"-it seemed so strange that dying she could see me while i had lost her,--"tell me, before i go." "believe in love," was all my soul could breathe. i heard no answer. only i felt her hand clasp mine and hold it tighter. then she died, and left me to my darkness. could i guess at unseen glories, in this deeper night, make new discoveries of profounder realms, within the soul? o, could i find him there, rise to him through his harmonies of law and make his will my own! this much, at least, i know already, that--in some strange way-his law implies his love; for, failing that all grows discordant, and the primal power ignobler than his children. so i trust one day to find her, waiting for me still, when all things are made new. i raise this torch of knowledge. it is one with my right hand, and the dark sap that keeps it burning flows out of my heart; and yet, for all my faith, it shows me only darkness. was i wrong? did i forget the subtler truth of rome and, in my pride, obscure the world's one light? did i subordinate to this moving earth our swiftlier-moving god? o, my celeste, once, once at least, you knew far more than i; and she is dead, castelli, she is dead. vi (_viviani, many years later, writes to a friend in england_) i was his last disciple, as you say i went to him, at seventeen years of age, and offered him my hands and eyes to use, when, voicing the true mind and heart of rome, father castelli, his most faithful friend, wrote, for my master, that compassionate plea; _the noblest eye that nature ever made is darkened; one so exquisitely dowered, so delicate in power that it beheld more than all other eyes in ages gone and opened the eyes of all that are to come._ but, out of england, even then, there shone the first ethereal promise of light that crowns my master dead. well i recall that day of days. there was no faintest breath among his garden cypress-trees. they dreamed dark, on a sky too beautiful for tears, and the first star was trembling overhead, when, quietly as a messenger from heaven, moving unseen, through his own purer realm, amongst the shadows of our mortal world, a young man, with a strange light on his face knocked at the door of galileo's house. his name was milton. by the hand of god, he, the one living soul on earth with power to read the starry soul of this blind man, was led through italy to his prison door. he looked on galileo, touched his hand ... _o, dark, dark, dark, amid the blaze of noon, irrecoverably dark .... _ in after days, he wrote it; but it pulsed within him then; and galileo rising to his feet and turning on him those unseeing eyes that had searched heaven and seen so many worlds, said to him, "you have found me." often he told me in those last sad months of how your grave young island poet brought peace to him, with the knowledge that, far off, in other lands, the truth he had proclaimed was gathering power. soon after, death unlocked his prison, and the city that he loved, florence, his town of flowers, whose gates in life he was forbid to pass, received him dead. you write to me from england, that his name is now among the mightiest in the world, and in his name i thank you. i am old; and i was very young when, long ago, i stood beside his poor dishonoured grave where hate denied him even an epitaph; and i have seen, slowly and silently, his purer fame arising, like a moon in marble on the twilight of those aisles at santa croce, where the dread decree was read against him. now, against two wrongs, let me defend two victims: first, the church whom many have vilified for my master's doom; and second, galileo, whom they reproach because they think that in his blind old age he might with one great eagle's glance have cowed his judges, played the hero, raised his hands above his head, and posturing like a mummer cried (as one empty rumour now declares) after his recantation--_yet, it moves_! out of this wild confusion, fourfold wrongs are heaped on both sides.--i would fain bring peace, the peace of truth to both before i die; and, as i hope, rest at my master's feet. it was not rome that tried to murder truth; but the blind hate and vanity of man. had galileo but concealed the smile with which, like socrates, he answered fools, they would not, in the name of christ, have mixed this hemlock in his chalice. o pitiful pitiful human hearts that must deny their own unfolding heavens, for one light word twisted by whispering malice. did he mean simplicio, in his dialogues, for the pope? doubtful enough--the name was borrowed straight from older dialogues. if he gave one thought of urban's to simplicio--you know well how composite are all characters in books, how authors find their colours here and there, and paint both saints and villains from themselves. no matter. this was urban. make it clear. simplicio means a simpleton. the saints are aroused by ridicule to most human wrath. urban was once his friend. this hint of ours kills all of that. and so we mortals close the doors of love and knowledge on the world. and so, for many an age, the name of christ has been misused by man to mask man's hate. how should the church escape, then? i who loved my master, know he had no truer friend than many of those true servants of the church, fathers and priests who, in their lowlier sphere, moved nearer than her cardinals to the christ. these were the very rome, and held her keys. those who charge rome with hatred of the light would charge the sun with darkness, and accuse this dome of sky for all the blood-red wrongs that men commit beneath it. art and song that found her once in europe their sole shrine and sanctuary absolve her from that stain. but there's this other charge against my friend, and master, galileo. it is brought by friends, made sharper by their pity and grief, the charge that he refused his martyrdom and so denied his own high faith. whose faith,-his friends', his protestant followers', or his own? faced by the torture, that sublime old man was still a faithful catholic, and his thought plunged deeper than his protestant followers knew. his aim was not to strike a blow at rome but to confound his enemies. he believed as humbly as castelli or celeste that there is nothing absolute but that power with which his church confronted him. to this he bowed his head, acknowledging that his light was darkness; but affirming, all the more, that ptolemy's light was even darker yet. read your own protestant milton, who derived his mighty argument from my master's lips: _"whether the sun predominant in heaven rise on the earth, or earth rise on the sun; leave them to god above; him serve and fear."_ just as in boyhood, when my master watched the swinging lamp in the cathedral there at pisa; and, by one finger on his pulse, found that, although the great bronze miracle swung through ever-shortening spaces, yet it moved more slowly, and so still swung in equal times; he straight devised another boon to man, those pulse-clocks which by many a fevered bed our doctors use; dreamed of that timepiece, too, whose punctual swinging pendulum on earth measures the starry periods, and to-day talks peacefully to children by the fire like an old grandad full of ancient tales, remembering endless ages, and foretelling eternities to come; but, all the while there, in the dim cathedral, he knew well, that dreaming youngster, with his tawny mane of red-gold hair, and deep ethereal eyes, what odorous clouds of incense round him rose; was conscious in the dimness, of great throngs kneeling around him; shared in his own heart the music and the silence and the cry, _o, salutaris hostia!_--so now, there was no mortal conflict in his mind between his dream-clocks and things absolute, and one far voice, most absolute of all, feeble with suffering, calling night and day "_return, return_;" the voice of his celeste. all these things co-existed, and the less were comprehended, like the swinging lamp, within that great cathedral of his soul. often he bade me, in that desolate house _il giojello_, of old a jewel of light, read to him one sad letter, till he knew the most of it by heart, and while he walked his garden, leaning on my arm, at times i think he quite forgot that i was there; for he would quietly murmur it to himself, as if she had sent it, half an hour ago: "now, with this little winter's gift of fruit i send you, father, from our southward wall, our convent's rarest flower, a christmas rose. at this cold season, it should please you much, seeing how rare it is; but, with the rose, you must accept its thorns, which bring to mind our lord's own bitter passion. its green leaves image the hope that through his passion we, after this winter of our mortal life, may find the beauty of an eternal spring in heaven." praise me the martyr, out of whose agonies some great new hope is born, but not the fool who starves his heart to prove what eyes can see and intellect confirm throughout the world. why must he follow the idiot schoolboy code, torture his soul to reinforce the sight of those that closed their eyes and would not see. to your own men of science, fifty turns of the thumbscrew would not prove that earth revolved. call it italian subtlety if you will, i say his intricate cause could not be won by blind heroics. much that his enemies challenged was not yet wholly proven, though his mind had leapt to a certainty. he must leave the rest to those that should come after, swift and young,-those runners with the torch for whom he longed as his deliverers. had he chosen death before his hour, his proofs had been obscured for many a year. his respite gave him time to push new pawns out, in the blindfold play of those last months, and checkmate, not the church but those that hid behind her. he believed his truth was all harmonious with her own. how could he choose between them? must he die to affirm a discord that himself denied? on many a point, he was less sure than we: but surer far of much that we forget the movements that he saw he could but judge by some fixed point in space. he chose the sun. could this be absolute? could he then be sure that this great sun did not with all its worlds move round a deeper centre? what became of your copernicus then? could he be sure of any unchanging centre, whence to judge this myriad-marching universe, but one-the absolute throne of god. affirming this eternal rock, his own uncertainties became more certain, and although his lips breathed not a syllable of it, though he stood silent as earth that also seemed so still, the very silence thundered, _yet it moves_! he held to what he knew, secured his work through feeble hands like mine, in other lands, not least in england, as i think you know. for, partly through your poet, as i believe, when his great music rolled upon your skies, new thoughts were kindled in the general mind. 'twas at arcetri that your milton gained the first great glimpse of his celestial realm. picture him,--still a prisoner of our light, closing his glorious eyes--that in the dark, he might behold this wheeling universe,-the planets gilding their ethereal horns with sun-fire. many a pure immortal phrase in his own work, as i have pondered it, lived first upon the lips of him whose eyes were darkened first,--in whom, too, milton found that samson agonistes, not himself, as many have thought, but my dear master dead. these are a part of england's memories now, the music blown upon her sea-bright air when, in the year of galileo's death, newton, the mightiest of the sons of light, was born to lift the splendour of this torch and carry it, as i heard that tycho said long since to kepler, "carry it out of sight, into the great new age i must not know, into the great new realm i must not tread." v newton i if i saw farther, 'twas because i stood on giant shoulders," wrote the king of thought, too proud of his great line to slight the toils of his forebears. he turned to their dim past, their fading victories and their fond defeats, and knelt as at an altar, drawing all their strengths into his own; and so went forth with all their glory shining in his face, to win new victories for the age to come. so, where copernicus had destroyed the dream we called our world; where galileo watched those ancient firmaments melt, a thin blue smoke into a vaster night; where kepler heard only stray fragments, isolated chords of that tremendous music which should bind all things anew in one, newton arose and carried on their fire. around him reeled through lingering fumes of hate and clouds of doubt, lit by the afterglow of the civil war, the dissolute throngs of that walpurgis night where all the cynical spirits that deny danced with the vicious lusts that drown the soul in flesh too gross for circe or her swine. but, in his heart, he heard one instant voice. _"on with the torch once more, make all things new, build the new heaven and earth, and save the world."_ ah, but the infinite patience, the long months lavished on tasks that, to the common eye, were insignificant, never to be crowned with great results, or even with earth's rewards. could rembrandt but have painted him, in those hours making his first analysis of light alone, there, in his darkened cambridge room at trinity! could he have painted, too, the secret glow, the mystery, and the power, the sense of all the thoughts and unseen spires that soared to heaven around him! he stood there, obscure, unknown, the shadow of a man in darkness, like a grey dishevelled ghost, --bare-throated, down at heel, his last night's supper littering his desk, untouched; his glimmering face, under his tangled hair, intent and still,-preparing our new universe. he caught the sunbeam striking through that bullet-hole in his closed shutter--a round white spot of light upon a small dark screen. he interposed a prism of glass. he saw the sunbeam break and spread upon the screen its rainbow band of disentangled colours, all in scale like notes in music; first, the violet ray, then indigo, trembling softly into blue; then green and yellow, quivering side by side; then orange, mellowing richly into red. then, in the screen, he made a small, round hole like to the first; and through it passed once more each separate coloured ray. he let it strike another prism of glass, and saw each hue bent at a different angle from its path, the red the least, the violet ray the most; but all in scale and order, all precise as notes in music. last, he took a lens, and, passing through it all those coloured rays, drew them together again, remerging all on that dark screen, in one white spot of light. so, watching, testing, proving, he resolved the seeming random glories of our day into a constant harmony, and found how in the whiteness of the sunlight sleep compounded, all the colours of the world. he saw how raindrops in the clouds of heaven breaking the light, revealed that sevenfold arch of colours, ranged as on his own dark screen, though now they spanned the mountains and wild seas. then, where that old-world order had gone down beneath a darker deluge, he beheld gleams of the great new order and recalled --fraught with new meaning and a deeper hope-that covenant which god made with all mankind throughout all generations: _i will set my bow in the cloud, that henceforth ye may know how deeper than the wreckage of your dreams abides my law, in beauty and in power. _ ii yet for that exquisite balance of the mind, he, too, must pay the price. he stood alone bewildered, at the sudden assault of fools on this, his first discovery. "i have lost the most substantial blessing of my quiet to follow a vain shadow. i would fain attempt no more. so few can understand, or read one thought. so many are ready at once to swoop and sting. indeed i would withdraw for ever from philosophy." so he wrote in grief, the mightiest mind of that new age. let those who'd stone the roman curia for all the griefs that galileo knew remember the dark hours that well-nigh quenched the splendour of that spirit. he could not sleep. yet, with that patience of the god in man that still must seek the splendour whence it came, through midnight hours of mockery and defeat, in loneliness and hopelessness and tears, he laboured on. he had no power to see how, after many years, when he was dead, out of this new discovery men should make an instrument to explore the farthest stars and, delicately dividing their white rays, divine what metals in their beauty burned, extort red secrets from the heart of mars, or measure the molten iron in the sun. he bent himself to nearer, lowlier, tasks; and seeing, first, that those deflected rays, though it were only by the faintest bloom of colour, imperceptible to our eyes, must dim the vision of galileo's glass, he made his own new weapon of the sky,-that first reflecting telescope which should hold in its deep mirror, as in a breathless pool the undistorted image of a star. iii in that deep night where galileo groped like a blind giant in dreams to find what power held moons and planets to their constant road through vastness, ordered like a moving fleet; what law so married them that they could not clash or sunder, but still kept their rhythmic pace as if those ancient tales indeed were true and some great angel helmed each gliding sphere; many had sought an answer. many had caught gleams of the truth; and yet, as when a torch is waved above a multitude at night, and shows wild streams of faces, all confused, but not the single law that knits them all into an ordered nation, so our skies for all those fragmentary glimpses, whirled in chaos, till one eagle-spirit soared, found the one law that bound them all in one, and through that awful unity upraised the soul to that which made and guides them all. did newton, dreaming in his orchard there beside the dreaming witham, see the moon burn like a huge gold apple in the boughs and wonder why should moons not fall like fruit? or did he see as those old tales declare (those fairy-tales that gather form and fire till, in one jewel, they pack the whole bright world) a ripe fruit fall from some immortal tree of knowledge, while he wondered at what height would this earth-magnet lose its darkling power? would not the fruit fall earthward, though it grew high o'er the hills as yonder brightening cloud? would not the selfsame power that plucked the fruit draw the white moon, then, sailing in the blue? then, in one flash, as light and song are born, and the soul wakes, he saw it--this dark earth holding the moon that else would fly through space to her sure orbit, as a stone is held in a whirled sling; and, by the selfsame power, her sister planets guiding all their moons; while, exquisitely balanced and controlled in one vast system, moons and planets wheeled around one sovran majesty, the sun. iv light and more light! the spark from heaven was there, the flash of that reintegrating fire flung from heaven's altars, where all light is born, to feed the imagination of mankind with vision, and reveal all worlds in one. but let no dreamer dream that his great work sprang, armed, like pallas from the thunderer's brain. with infinite patience he must test and prove his vision now, in those clear courts of truth whose absolute laws (bemocked by shallower minds as less than dreams, less than the faithless faith that fears the truth, lest truth should slay the dream) are man's one guide to his transcendent heaven; for there's no wandering splendour in the soul, but in the highest heaven of all is one with absolute reality. none can climb back to that fount of beauty but through pain. long, long he toiled, comparing first the curves traced by the cannon-ball as it soared and fell with that great curving road across the sky traced by the sailing moon. was earth a loadstone holding them to their paths by that dark force whose mystery men have cloaked beneath a name? yet, when he came to test and prove, he found that all the great deflections of the moon, her shining cadences from the path direct, were utterly inharmonious with the law of that dark force, at such a distance acting, measured from earth's own centre.... for three long years, newton withheld his hope until that day when light was brought from france, new light, new hope, in one small glistening fact, clear-cut as any diamond; and to him loaded with all significance, like the point of light that shows where constellations burn. picard in france--all glory to her name who is herself a light among all lands-had measured earth's diameter once more with exquisite precision. to the throng, those few corrected ciphers, his results, were less than nothing; yet they changed the world. for newton seized them and, with trembling hands, began to work his problem out anew. then, then, as on the page those figures turned to hieroglyphs of heaven, and he beheld the moving moon, with awful cadences falling into the path his law ordained, even to the foot and second, his hand shook and dropped the pencil. "work it out for me," he cried to those around him; for the weight of that celestial music overwhelmed him; and, on his page, those burning hieroglyphs were thrones and principalities and powers... for far beyond, immeasurably far beyond our sun, he saw that river of suns we call the milky way, that glittering host powdering the night, each grain of solar blaze divided from its neighbour by a gulf too wide for thought to measure; each a sun huger than ours, with its own fleet of worlds, visible and invisible. those bright throngs that seemed dispersed like a defeated host through blindly wandering skies, now, at the word of one great dreamer, height o'er height revealed hints of a vaster order, and moved on in boundless intricacies of harmony around one centre, deeper than all suns, the burning throne of god. v he could not sleep. that intellect, whose wings dared the cold ultimate heights of space and time sank, like a wounded eagle, with dazed eyes back, headlong through the clouds to throb on earth. what shaft had pierced him? that which also pierced his great forebears--the hate of little men. they flocked around him, and they flung their dust into the sensitive eyes and laughed to see how dust could blind them. if one prickling grain could so put out his vision and so torment that delicate brain, what weakness! how the mind that seemed to dwarf us, dwindles! is he mad? so buzzed the fools, whose ponderous mental wheels nor dust, nor grit, nor stones, nor rocks could irk even for an instant. newton could not sleep, but all that careful malice could design was blindly fostered by well-meaning folly, and great sane folk like mr. samuel pepys canvassed his weakness and slept sound all night. for little samuel with his rosy face came chirping into a coffee-house one day like a plump robin, "sir, the unhappy state of mr. isaac newton grieves me much. last week i had a letter from him, filled with strange complainings, very curious hints, such as, i grieve to say, are common signs --i have observed it often--of worse to come. he said that he could neither eat nor sleep because of all the embroilments he was in, hinting at nameless enemies. then he begged my pardon, very strangely. i believe physicians would confirm me in my fears. 'tis very sad.... only last night, i found among my papers certain lines composed by--whom d'you think?--my lord of halifax (or so dear mrs. porterhouse assured me) expressing, sir, the uttermost satisfaction in mr. newton's talent. sir, he wrote answering the charge that science would put out the light of beauty, these very handsome lines: 'when newton walked by witham stream there fell no chilling shade to blight the drifting naiad's dream or make her garland fade. the mist of sun was not less bright that crowned urania's hair. he robbed it of its colder light, but left the rainbow there.' they are very neat and handsome, you'll agree. solid in sense as dryden at his best, and smooth as waller, but with something more,-that touch of grace, that airier elegance which only rank can give. 'tis very sad that one so nobly praised should--well, no matter!-i am told, sir, that these troubles all began at cambridge, when his manuscripts were burned. he had been working, in his curious way, all through the night; and, in the morning greyness went down to chapel, leaving on his desk a lighted candle. you can imagine it,-a sadly sloven altar to his muse, littered with papers, cups, and greasy plates of untouched food. i am told that he would eat his monday's breakfast, sir, on tuesday morning, such was his absent way! when he returned, he found that diamond (his little dog named diamond, for a black patch near his tail) had overturned the candle. all his work was burned to ashes. it struck him to the quick, though, when his terrier fawned about his feet, he showed no anger. he was heard to say, 'o diamond, diamond, little do you know...' but, from that hour, ah well, we'll say no more." halley was there that day, and spoke up sharply, "sir, there are hints and hints! do you _mean_ more?" --"i do, sir," chirruped samuel, mightily pleased to find all eyes, for once, on his fat face. "i fear his intellects are disordered, sir." --"good! that's an answer! i can deal with that. but tell me first," quoth halley, "why he wrote that letter, a week ago, to mr. pepys." --"why, sir," piped samuel, innocent of the trap, "i had an argument in this coffee-house last week, with certain gentlemen, on the laws of chance, and what fair hopes a man might have of throwing six at dice. i happened to say that mr. isaac newton was my friend, and promised i would sound him." "sir," said halley, "you'll pardon me, but i forgot to tell you i heard, a minute since, outside these doors, a very modish woman of the town, or else a most delicious lady of fashion, a melting creature with a bold black eye, a bosom like twin doves; and, sir, a mouth like a turk's dream of paradise. she cooed, 'is mr. pepys within?' i greatly fear that they denied you to her!" off ran pepys! "a hint's a hint," laughed halley, "and so to bed. but, as for isaac newton, let me say, whatever his embroilments were, he solved with just one hour of thought, not long ago the problem set by leibnitz as a challenge to all of europe. he published his result anonymously, but leibnitz, when he saw it, cried out, at once, old enemy as he was, 'that's newton, none but newton! from this claw i know the old lion, in his midnight lair.'" vi (_sir isaac newton writes to mrs. vincent at woolthorpe._) your letter, on my eightieth birthday, wakes memories, like violets, in this london gloom. you have never failed, for more than three-score years to send these annual greetings from the haunts where you and i were boy and girl together. a day must come-it cannot now be far-when i shall have no power to thank you for them, so let me tell you now that, all my life, they have come to me with healing in their wings like birds from home, birds from the happy woods above the witham, where you walked with me when you and i were young. do you remember old barley--how he tried to teach us drawing? he found some promise, i believe, in you, but quite despaired of me. i treasure all those little sketches that you sent to me each christmas, carrying each some glimpse of home. there's one i love that shows the narrow lane behind the schoolhouse, where i had that bout of schoolboy fisticuffs. i have never known more pleasure, i believe, than when i beat that black-haired bully and won, for my reward, those april smiles from you. i see you still standing among the fox-gloves in the hedge; and just behind you, in the field, i know there was a patch of aromatic flowers,-rest-harrow, was it? yes; their tangled roots pluck at the harrow; halt the sharp harrow of thought, even in old age. i never breathe their scent but i am back in boyhood, dreaming there over some book, among the diligent bees, until you join me, and we dream together. they called me lazy, then. oddly enough it was that fight that stirred my mind to beat my bully at his books, and head the school; blind rivalry, at first. by such fond tricks the invisible power that shapes us--not ourselves-punishes, teaches, leads us gently on like children, all our lives, until we grasp a sudden meaning and are born, through death into full knowledge that our guide was love. another picture shows those woods of ours, around whose warm dark edges in the spring primroses, knots of living sunlight, woke; and, always, you, their radiant shepherdess from elfland, lead them rambling back for me, the dew still clinging to their golden fleece, through these grey memory-mists. another shows my old sun-dial. you say that it is known as "isaac's dial" still. i took great pains to set it rightly. if it has not shifted 'twill mark the time long after i am gone; not like those curious water-clocks i made. do you remember? they worked well at first; but the least particles in the water clogged the holes through which it dripped; and so, one day, we two came home so late that we were sent supperless to our beds; and suffered much from the world's harshness, as we thought it then. would god that we might taste that harshness now. i cannot send you what you've sent to me; and so i wish you'll never thank me more for those poor gifts i have sent from year to year. i send another, and hope that you can use it to buy yourself those comforts which you need this christmas-time. how strange it is to wake and find that half a century has gone by, with all our endless youth. they talk to me of my discoveries, prate of undying fame too late to help me. anything i achieved was done through work and patience; and the men who sought quick roads to glory for themselves were capable of neither. so i won their hatred, and it often hampered me, because it vexed my mind. this world of ours would give me all, now i have ceased to want it; for i sit here, alone, a sad old man, sipping his orange-water, nodding to sleep, not caring any more for aught they say, not caring any more for praise or blame; but dreaming-things we dreamed of, long ago, in childhood. you and i had laughed away that boy and girl affair. we were too poor for anything but laughter. i am old; and you, twice wedded and twice widowed, still retain, through all your nearer joys and griefs, the old affection. vaguely our blind old hands grope for each other in this growing dark and deepening loneliness,--to say "good-bye." would that my words could tell you all my heart; but even my words grow old. perhaps these lines, written not long ago, may tell you more. i have no skill in verse, despite the praise your kindness gave me, once; but since i wrote thinking of you, among the woods of home, my heart was in them. let them turn to yours: _give me, for friends, my own true folk who kept the very word they spoke; whose quiet prayers, from day to day, have brought the heavens about my way. not those whose intellectual pride would quench the only lights that guide; confuse the lines 'twixt good and ill then throne their own capricious will; not those whose eyes in mockery scan the simpler hopes and dreams of man; not those keen wits, so quick to hurt, so swift to trip you in the dirt. not those who'd pluck your mystery out, yet never saw your last redoubt; whose cleverness would kill the song dead at your heart, then prove you wrong. give me those eyes i used to know where thoughts like angels come and go; --not glittering eyes, nor dimmed by books, but eyes through which the deep soul looks. give me the quiet hands and face that never strove for fame and place; the soul whose love, so many a day has brought the heavens about my way._ vii _was it a dream, that low dim-lighted room with that dark periwigged phantom of dean swift writing, beside a fire, to one he loved,-beautiful catherine barton, once the light of newton's house, and his half-sister's child?_ yes, catherine barton, i am brave enough to face this pale, unhappy, wistful ghost of our departed friendship. it was i savage and mad, a snarling kennel of sins, "your holiness," as you called me, with that smile which even your ghost would quietly turn on me-who raised it up. it has no terrors, dear. and i shall never lay it while i live. you write to me. you think i have the power to shield the fame of newton from a lie. poor little ghost! you think i hold the keys not only of parnassus, then, but hell. there is a tale abroad that newton owed his public office to lord halifax, your secret lover. coarseness, as you know, is my peculiar privilege. i'll be plain, and let them wince who are whispering in the dark. they are hinting that he gained his public post through you, his flesh and blood; and that he knew you were his patron's mistress! yes, i know the coffee-house that hatched it--to be scotched, nay, killed, before one snuff-box could say "snap," had not one cold malevolent face been there listening,--that crystal-minded lover of truth, that lucid enemy of all lies,--voltaire. i am told he is doing much to spread the light of newton's great discoveries, there, in france. there's little fear that france, whose clear keen eyes have missed no morning in the realm of thought, would fail to see it; and smaller need to lift a brand from hell to illume the light from heaven. you fear he'll print his lie. no doubt of that. i can foresee the phrase, as halley saw the advent of his comet,--_jolie niece, assez amiable,_ ... then he'll give your name as _madame conduit_, adding just that spice of infidelity that the dates admit to none but these truth-lovers. it will be best not to enlighten him, or he'll change his tale and make an answer difficult. let him print this truth as he conceives it, and you'll need no more defence. all history then shall damn his death-cold lie and show you for the laughing child you were when newton won his office. for yourself you say you have no fear. your only thought is that they'll soil his fame. ah yes, they'll try, but they'll not hurt it. for all time to come it stands there, firm as marble and as pure. they can do nothing that the sun and rain will not erase at last. not even voltaire can hurt that noble memory. think of him as of a viper writhing at the base of some great statue. let the venomous tongue flicker against that marble as it may it cannot wound it. i am far more grieved for you, who sit there wondering now, too late, if it were some suspicion, some dark hint newton had heard that robbed him of his sleep, and almost broke his mind up. i recall how the town buzzed that newton had gone mad. you copy me that sad letter which he wrote to locke, wherein he begs him to forgive the hard words he had spoken, thinking locke had tried to embroil him, as he says, with women; a piteous, humble letter. had he heard some hint of scandal that he could not breathe to you, because he honoured you too well? i cannot tell. his mind was greatly troubled with other things. at least, you need not fear that newton thought it true. he walked aloof, treading a deeper stranger world than ours. have you not told me how he would forget even to eat and drink, when he was wrapt in those miraculous new discoveries and, under this wild maze of shadow and sun beheld--though not the master player's hand-the keys from which his organ music rolls, those visible symphonies of wild cloud and light which clothe the invisible world for mortal eyes. i have heard that leibnitz whispered to the court that newton was an "atheist." leibnitz knew his audience. he could stoop to it. fools have said that knowledge drives out wonder from the world; they'll say it still, though all the dust's ablaze with miracles at their feet; while newton's laws foretell that knowledge one day shall be song, and those whom truth has taken to her heart find that it beats in music. even this age has glimmerings of it. newton never saw his own full victory; but at least he knew that all the world was linked in one again; and, if men found new worlds in years to come, these too must join the universal song. that's why true poets love him; and you'll find their love will cancel all that hate can do. they are the sentinels of the house of fame; and that quick challenging couplet from the pen of alexander pope is answer enough to all those whisperers round the outer doors. there's addison, too. the very spirit and thought of newton moved to music when he wrote _the spacious firmament_. some keen-eyed age to come will say, though newton seldom wrote a verse, that music was his own and speaks his faith. and, last, for those who doubt his faith in god and man's immortal destiny, there remains the granite monument of his own great work, that dark cathedral of man's intellect, the vast "principia," pointing to the skies, wherein our intellectual king proclaimed the task of science,--through this wilderness of time and space and false appearances, to make the path straight from effect to cause, until we come to that first cause of all, the power, above, beyond the blind machine, the primal power, the originating power, which cannot be mechanical. he affirmed it with absolute certainty. whence arises all this order, this unbroken chain of law, this human will, this death-defying love? whence, but from some divine transcendent power, not less, but infinitely more than these, because it is their fountain and their guide. fools in their hearts have said, "whence comes this power, why throw the riddle back this one stage more?" and newton, from a height above all worlds answered and answers still: "this universe exists, and by that one impossible fact declares itself a miracle; postulates an infinite power within itself, a whole greater than any part, a unity sustaining all, binding all worlds in one. this is the mystery, palpable here and now. 'tis not the lack of links within the chain from cause to cause, but that the chain exists. that's the unfathomable mystery, the one unquestioned miracle that we _know_, implying every attribute of god, the ultimate, absolute, omnipresent power, in its own being, deep and high as heaven. but men still trace the greater to the less, account for soul with flesh and dreams with dust, forgetting in their manifold world the one, in whom for every splendour shining here abides an equal power behind the veil. was the eye contrived by blindly moving atoms, or the still-listening ear fulfilled with music by forces without knowledge of sweet sounds? are nerves and brain so sensitively fashioned that they convey these pictures of the world into the very substance of our life, while that from which we came, the power that made us, is drowned in blank unconsciousness of all? does it not from the things we know appear that there exists a being, incorporeal, living, intelligent, who in infinite space, as in his infinite sensory, perceives things in themselves, by his immediate presence everywhere? of which things, we see no more than images only, flashed through nerves and brain to our small sensories? what is all science then but pure religion, seeking everywhere the true commandments, and through many forms the eternal power that binds all worlds in one? it is man's age-long struggle to draw near his maker, learn his thoughts, discern his law,-a boundless task, in whose infinitude, as in the unfolding light and law of love. abides our hope, and our eternal joy. i know not how my work may seem to others--" so wrote our mightiest mind--"but to myself i seem a child that wandering all day long upon the sea-shore, gathers here a shell, and there a pebble, coloured by the wave, while the great ocean of truth, from sky to sky stretches before him, boundless, unexplored." he has explored it now, and needs of me neither defence nor tribute. his own work remains his monument he rose at last so near the power divine that none can nearer go; none in this age! to carry on his fire we must await a mightier age to come. vi william herschel conducts _was it a dream?--that crowded concert-room in bath; that sea of ruffles and laced coats; and william herschel, in his powdered wig, waiting upon the platform, to conduct his choir and linley's orchestra? he stood tapping his music-rest, lost in his own thoughts and (did i hear or dream them?) all were mine:_ my periwig's askew, my ruffle stained with grease from my new telescope! ach, to-morrow how caroline will be vexed, although she grows almost as bad as i, who cannot leave my work-shop for one evening. i must give one last recital at st. margaret's, and then--farewell to music. who can lead two lives at once? yet--it has taught me much, thrown curious lights upon our world, to pass from one life to another. much that i took for substance turns to shadow. i shall see no throngs like this again; wring no more praise out of their hearts; forego that instant joy --let those who have not known it count it vain-when human souls at once respond to yours. here, on the brink of fortune and of fame, as men account these things, the moment comes when i must choose between them and the stars; and i have chosen. handel, good old friend, we part to-night. hereafter, i must watch that other wand, to which the worlds keep time. what has decided me? that marvelous night when--ah, how difficult it will be to guide, with all these wonders whirling through my brain!-after a pump-room concert i came home hot-foot, out of the fluttering sea of fans, coquelicot-ribboned belles and periwigged beaux, to my newtonian telescope. the design was his; but more than half the joy my own, because it was the work of my own hand, a new one, with an eye six inches wide, better than even the best that newton made. then, as i turned it on the _gemini_, and the deep stillness of those constant lights, castor and pollux, lucid pilot-stars, began to calm the fever of my blood, i saw, o, first of all mankind i saw the disk of my new planet gliding there beyond our tumults, in that realm of peace. what will they christen it? ach--not _herschel_, no! nor _georgium sidus_, as i once proposed; although he scarce could lose it, as he lost that world in 'seventy-six. indeed, so far from trying to tax it, he has granted me how much?--two hundred golden pounds a year, in the great name of science,--half the cost of one state-coach, with all those worlds to win! well--well--we must be grateful. this mad king has done far more than all the worldly-wise, who'll charge even this to madness. i believe one day he'll have me pardoned for that...crime, when i escaped--deserted, some would say-from those drill-sergeants in my native land; deserted drill for music, as i now desert my music for the orchestral spheres. no. this new planet is only new to man. his majesty has done much. yet, as my friend declared last night, "never did monarch buy honour so cheaply"; and--he has not bought it. i think that it should bear some ancient name, and wear it like a crown; some deep, dark name, like _uranus_, known to remoter gods. how strange it seems--this buzzing concert-room! there's doctor burney bowing and, behind him, his fox-eyed daughter fanny. is it a dream, these crowding midgets, dense as clustering bees in some great bee-skep? now, as i lift my wand, a silence grips them, and the strings begin, throbbing. the faint lights flicker in gusts of sound. before me, glimmering like a crescent moon, the dim half circle of the choir awaits its own appointed time. beside me now, watching my wand, plump and immaculate from buckled shoes to that white bunch of lace under his chin, the midget tenor rises, music in hand, a linnet and a king. the bullfinch bass, that other emperor, leans back indifferently, and clears his throat as if to say, "this prelude leads to _me_!" while, on their own proud thrones, on either hand, the sumptuously bosomed midget queens, contralto and soprano, jealously eye each other's plumage. round me the music throbs with an immortal passion. i grow aware of an appalling mystery.... we, this throng of midgets, playing, listening, tense and still, are sailing on a midget ball of dust we call our planet; will have sailed through space ten thousand leagues before this music ends. what does it mean? oh, god, what _can_ it mean?-this weird hushed ant-hill with a thousand eyes; these midget periwigs; all those little blurs, tier over tier, of faces, masks of flesh, corruptible, hiding each its hopes and dreams, its tragi-comic dreams. and all this throng will be forgotten, mixed with dust, crushed out, before this book of music is outworn or that tall organ crumbles. violins outlast their players. other hands may touch that harpsichord; but ere this planet makes another threescore journeys round its sun, these breathing listeners will have vanished. whither? i watch my moving hands, and they grow strange! what is it moves this body? what am i? how came i here, a ghost, to hear that voice of infinite compassion, far away, above the throbbing strings, hark! _comfort ye_... if music lead us to a cry like this, i think i shall not lose it in the skies. i do but follow its own secret law as long ago i sought to understand its golden mathematics; taught myself the way to lay one stone upon another, before i dared to dream that i might build my holy city of song. i gave myself to all its branches. how they stared at me, those men of "sensibility," when i said that algebra, conic sections, fluxions, all pertained to music. let them stare again. old kepler knew, by instinct, what i now desire to learn. i have resolved to leave no tract of heaven unvisited. to-night --the music carries me back to it again!-i see beyond this island universe, beyond our sun, and all those other suns that throng the milky way, far, far beyond, a thousand little wisps, faint nebulae, luminous fans and milky streaks of fire; some like soft brushes of electric mist streaming from one bright point; others that spread and branch, like growing systems; others discrete, keen, ripe, with stars in clusters; others drawn back by central forces into one dense death, thence to be kindled into fire, reborn, and scattered abroad once more in a delicate spray faint as the mist by one bright dewdrop breathed at dawn, and yet a universe like our own; each wisp a universe, a vast galaxy wide as our night of stars. the milky way in which our sun is drowned, to these would seem less than to us their faintest drift of haze; yet we, who are borne on one dark grain of dust around one indistinguishable spark of star-mist, lost in one lost feather of light, can by the strength of our own thought, ascend through universe after universe; trace their growth through boundless time, their glory, their decay; and, on the invisible road of law, more firm than granite, range through all their length and breadth, their height and depth, past, present and to come. so, those who follow the great work-master's law from small things up to great, may one day learn the structure of the heavens, discern the whole within the part, as men through love see god. oh, holy night, deep night of stars, whose peace descends upon the troubled mind like dew, healing it with the sense of that pure reign of constant law, enduring through all change; shall i not, one day, after faithful years, find that thy heavens are built on music, too, and hear, once more, above thy throbbing worlds this voice of all compassion, _comfort ye,--_ yes--_comfort ye, my people, saith your god?_ vii sir john herschel remembers true type of all, from his own father's hand he caught the fire; and, though he carried it far into new regions; and, from southern fields of yellow lupin, added host on host to those bright armies which his father knew, surely the crowning hour of all his life was when, his task accomplished, he returned a lonely pilgrim to the twilit shrine of first beginnings and his father's youth. there, in the octagon chapel, with bared head grey, honoured for his father and himself, he touched the glimmering keyboard, touched the books those dear lost hands had touched so long ago. "strange that these poor inanimate things outlast the life that used them. yes. i should like to try this good old friend of his. you'll leave me here an hour or so?" his hands explored the stops; and, while the music breathed what else were mute, his mind through many thoughts and memories ranged. picture on picture passed before him there in living colours, painted on the gloom: not what the world acclaimed, the great work crowned, but all that went before, the years of toil; the years of infinite patience, hope, despair. he saw the little house where all began, his father's first resolve to explore the sky, his first defeat, when telescopes were found too costly for a music-master's purse; and then that dogged and all-conquering will declaring, "be it so. i'll make my own, a better than even the best that newton made." he saw his first rude telescope--a tube of pasteboard, with a lens at either end; and then,--that arduous growth to size and power with each new instrument, as his knowledge grew; and, to reward each growth, a deeper heaven. he saw the good aunt caroline's dismay when her trim drawing-room, as by wizardry, turned into a workshop, where her brother's hands cut, ground and burnished, hour on aching hour, month after month, new mirrors of the sky. yet, while from dawn to dark her brother moved around some new-cut mirror, burnishing it, knowing that if he once removed his hands the surface would be dimmed and must forego its heaven for ever, her quiet hands would raise food to his lips; or, with that musical voice which once--for she, too, offered her sacrifice-had promised her fame, she whiled away the hours reading how, long ago, aladdin raised the djinns, by burnishing that old battered lamp; or, from cervantes, how one crazy soul tilting at windmills, challenged a purblind world. he saw her seized at last by that same fire, burning to help, a sleepless vestal, dowered with lightning-quickness, rushing from desk to clock, or measuring distances at dead of night between the lamp-micrometer and his eyes. he saw her in mid-winter, hurrying out, a slim shawled figure through the drifted snow, to help him; saw her fall with a stifled cry, gashing herself upon that buried hook, and struggling up, out of the blood-stained drift, to greet him with a smile. "for any soldier, this wound," the surgeon muttered, "would have meant six weeks in hospital." not six days for her! "i am glad these nights were cloudy, and we lost so little," was all she said. sir john pulled out another stop. a little ironical march of flutes began to goose-step through the gloom. he saw that first "success"! ay, call it so! the royal command,--the court desires to see the planet saturn and his marvellous rings on friday night. the skies, on friday night, were black with clouds. "canute me no canutes," muttered their new magician, and unpacked his telescope. "you shall see what you can see." he levelled it through a window; and they saw "wonderful! marvellous! glorious! eh, what, what!" a planet of paper, with a paper ring, lit by a lamp, in a hollow of windsor park, among the ferns, where herne the hunter walks, and falstaff found that fairies live on cheese. thus all were satisfied; while, above the clouds-the thunder of the pedals reaffirmed-the titan planet, every minute, rolled three hundred leagues upon his awful way. then, through that night, the _vox humana_spoke with deeper longing than lucretius knew when, in his great third book, the somber chant kindled and soared on those exultant wings, praising the master's hand from which he, too, --father, discoverer, hero--caught the fire. it spoke of those vast labours, incomplete, but, through their incompletion, infinite in beauty, and in hope; the task bequeathed from dying hand to hand. close to his grave like a _memento mori_ stood the hulk of that great weapon rusted and outworn, which once broke down the barriers of the sky. _"perrupit claustra"_; yes, and bridged their gulfs; for, far beyond our solar scheme, it showed the law that bound our planets binding still those coupled suns which year by year he watched around each other circling. had our own some distant comrade, lost among the stars? should we not, one day, just as kepler drew his planetary music and its laws from all those faithful records tycho made, discern at last what vaster music rules the vaster drift of stars from deep to deep; around what awful poles, those wisps of light those fifteen hundred universes move? one signal, even now, across the dark, declared their worlds confederate with our own; for, carrying many secrets, which we now slowly decipher, one swift messenger comes across the abyss... the light that, flashing through the immeasurable, from universe to universe proclaims the single reign of law that binds them all. we shall break up those rays and, in their lines and colours, read the history of their stars. year after year, the slow sure records grow. awaiting their interpreter. they shall see it, our sons, in that far day, the swift, the strong, the triumphing young-eyed runners with the torch. no deep-set boundary-mark in space or time shall halt or daunt them. who that once has seen how truth leads on to truth, shall ever dare to set a bound to knowledge? "would that he knew" --so thought the visitant at that shadowy shrine-"even as the maker of a song can hear with the soul's ear, far off, the unstricken chords to which, by its own inner law, it climbs, would that my father knew how younger hands completed his own planetary tune; how from the planet that his own eyes found the mind of man would plunge into the dark, and, blindfold, find without the help of eyes a mightier planet, in the depths beyond." then, while the reeds, with quiet melodious pace followed the dream, as in a picture passed, adams, the boy at cambridge, making his vow by that still lamp, alone in that deep night, beneath the crumbling battlements of st. john's, to know why uranus, uttermost planet known, moved in a rhythm delicately astray from all the golden harmonies ordained by those known measures of its sister-worlds. was there an unknown planet, far beyond, sailing through unimaginable deeps and drawing it from its path? then challenging chords echoed the prophecy that sir john had made, guided by his own faith in newton's law: _we have not found it, but we feel it trembling along the lines of our analysis now as once columbus, from the shores of spain, felt the new continent._ then, in swift fugues, began a race between two nations for the prize of that new world. le verrier in france, adams in england, each of them unaware of his own rival, at the selfsame hour resolved to find it. not by the telescope now! skies might be swept for aeons ere one spark among those myriads were both found and seen to move, at that vast distance round our sun. they worked by faith in law alone. they knew the wanderings of great uranus, and they knew the law of newton. by the midnight lamp, pencil in hand, shut in a four-walled room, each by pure thought must work his problem out,-given that law, to find the mass and place of that which drew their planet from his course. there were no throngs to applaud them. each alone, without the heat of conflict laboured on, consuming brain and nerve; for throngs applaud only the flash and tinsel of their day, never the quiet runners with the torch. night after night they laboured. line on line of intricate figures, moving all in law, they marshalled. their long columns formed and marched from battle to battle, and no sound was heard of victory or defeat. they marched through snows bleak as the drifts that broke napoleon's pride and through a vaster desert. they drilled their hosts with that divine precision of the mind to which one second's error in a year were anarchy, that precision which is felt throbbing through music. month on month they toiled, with worlds for ciphers. one rich autumn night brooding over his figures there alone in cambridge, adams found them moving all to one solution. to the unseeing eye his long neat pages had no more to tell than any merchant's ledger, yet they shone with epic splendour, and like trumpets pealed; _three hundred million leagues beyond the path of our remotest planet, drowned in night another and a mightier planet rolls; in volume, fifty times more vast than earth, and of so huge an orbit that its year wellnigh outlasts our nations. though it moves a thousand leagues an hour, it has not ranged thrice through its seasons since columbus sailed, or more than once since galileo died._ he took his proofs to greenwich. "sweep the skies within this limited region now," he said. "you'll find your moving planet. i'm not more than one degree in error." he left his proofs; but airy, king of greenwich, looked askance at unofficial genius in the young, and pigeon-holed that music of the spheres. nine months he waited till le verrier, too, pointed to that same region of the sky. then airy, opening his big sleepy lids, bade challis use his telescope,--too late, to make that honour all his country's own; for all le verrier's proofs were now with galle who, being german, had his star-charts ready and, in that region, found one needlepoint had moved. a monster planet! honour to france! honour to england, too, the cry began, who found it also, though she drowsed at greenwich. so--as the french said, with some sting in it-"we gave the name of neptune to our prize because our neighbour england rules the sea." "honour to all," say we; for, in these wars, whoever wins a battle wins for all. but, most of all, honour to him who found the law that was a lantern to their feet,-newton, the first whose thought could soar beyond the bounds of human vision and declare, "thus saith the law of nature and of god concerning things invisible." this new world what was it but one harmony the more in that great music which himself had heard,-the chant of those reintegrated spheres moving around their sun, while all things moved around one deeper light, revealed by law, beyond all vision, past all understanding. yet darkly shadowed forth for dreaming men on earth in music... music, all comes back to music in the end. then, in the gloom of the octagon chapel, the dreamer lifted up his face, as if to all those great forebears. the quivering organ rolled upon the dusk his dream of that new symphony,--the sun chanting to all his planets on their way while, stop to stop replying, height o'er height, his planets answered, voices of a dream: the sun light, on the far faint planets that attend me! light! but for me-the fury and the fire. my white-hot maelstroms, the red storms that rend me can yield them still the harvest they desire, i kiss with light their sunward-lifted faces. with dew-drenched flowers i crown their dusky brows. they praise me, lightly, from their pleasant places. their birds belaud me, lightly, from their boughs. and men, on lute and lyre, have breathed their pleasure. they have watched apollo's golden chariot roll; hymned his bright wheels, but never mine that measure a million leagues of flame from pole to pole. like harbour-lights the stars grow wide before me, i draw my worlds ten thousand leagues a day. their far blue seas like april eyes adore me. they follow, dreaming, on my soundless way. how should they know, who wheel around my burning, what torments bore them, or what power am i, i, that with all those worlds around me turning, sail, every hour, from sky to unplumbed sky? my planets, these live embers of my passion, these children of my hurricanes of flame, flung thro' the night, for midnight to refashion, praise, and forget, the splendour whence they came. the earth _was it a dream that, in those bright dominions, are other worlds that sing, with lives like mine, lives that with beating hearts and broken pinions aspire and fall, half-mortal, half-divine? a grain of dust among those glittering legions- am i, i only, touched with joy and tears? 0, silver sisters, from your azure regions, breathe, once again, your music of the spheres:--_ venus a nearer sun, a rose of light arises, to clothe my glens with richer clouds of flowers, to paint my clouds with ever new surprises and wreathe with mist my rosier domes and towers; where now, to praise their gods, a throng assembles whose hopes and dreams no sphere but mine has known. on other worlds the same warm sunlight trembles; but life, love, worship, these are mine alone. mars and now, as dewdrops in the dawn-light glisten, remote and cold--see--earth and venus roll. we signalled them--in music! did they listen? could they not hear those whispers of the soul? may not their flesh have sealed that fount of glory, that pure ninth sense which told us of mankind? can some deep sleep bereave them of our story as darkness hides all colours from the blind? jupiter i that am sailing deeper skies and dimmer, twelve million leagues beyond the path of mars, salute the sun, that cloudy pearl, whose glimmer renews my spring and steers me through the stars. think not that i by distances am darkened. my months are years; yet light is in mine eyes. mine eyes are not as yours. mine ears have hearkened to sounds from earth. five moons enchant my skies. saturn and deeper yet, like molten opal shining my belt of rainbow glory softly streams. and seven white moons around me intertwining hide my vast beauty in a mist of dreams. huge is my orbit; and your flickering planet a mote that flecks your sun, that faint white star; yet, in my magic pools, i still can scan it; for i have ways to look on worlds afar. uranus and deeper yet--twelve million leagues of twilight divide mine empire even from saturn's ken. is there a world whose light is not as my light, a midget world of light-imprisoned men? shut from this inner vision that hath found me, they hunt bright shadows, painted to betray; and know not that, because their night hath drowned me, my giants walk with gods in boundless day. neptune plunge through immensity anew and find me. though scarce i see your sun,--that dying spark- across a myriad leagues it still can bind me to my sure path, and steer me through the dark. i sail through vastness, and its rhythms hold me, though threescore earths could in my volume sleep! whose are the might and music that enfold me? whose is the law that guides me thro' the deep? the sun _i hear their song. they wheel around my burning! i know their orbits; but what path have i? i that with all those worlds around me turning sail, every hour, ten thousand leagues of sky?_ _my planets, these live embers of my passion, and i, too, filled with music and with flame. flung thro' the night, for midnight to refashion, praise and forget the splendour whence we came._ epilogue once more upon the mountain's lonely height i woke, and round me heard the sea-like sound of pine-woods, as the solemn night-wind washed through the long canyons and precipitous gorges where coyotes moaned and eagles made their nest. once more, far, far below, i saw the lights of distant cities, at the mountain's feet, clustered like constellations.. . over me, like the dome of some strange shrine, housing our great new weapon of the sky, and moving on its axis like a moon glimmered the new uraniborg. shadows passed like monks, between it and the low grey walls that lodged them, like a fortress in the rocks, their monastery of thought. a shadow neared me. i heard, once more, an eager living voice: "year after year, the slow sure records grow. i wish that old copernicus could see how, through his truth, that once dispelled a dream, broke the false axle-trees of heaven, destroyed all central certainty in the universe, and seemed to dwarf mankind, the spirit of man laid hold on law, that jacob's-ladder of light, and mounting, slowly, surely, step by step, entered into its kingdom and its power. for just as tycho's tables of the stars within the bound of our own galaxy led kepler to the music of his laws, so, father and son, the herschels, with their charts of all those fire-mists, those faint nebulae, those hosts of drifting universes, led our new discoverers to yet mightier laws enthroned above all worlds. we have not found them, and yet--only the intellectual fool dreams in his heart that even his brain can tick in isolated measure, a centre of law, amidst the whirl of universal chaos. for law descends from law. though all the spheres through all the abysmal depths of space were blown like dust before a colder darker wind than even lucretius dreamed, yet if one thought, one gleam of law within the mind of man, lighten our darkness, there's a law beyond; and even that tempest of destruction moves to a lighter music, shatters its myriad worlds only to gather them up, as a shattered wave is gathered again into a rhythmic sea, whose ebb and flow are but the pulse of life, in its creative passion. the records grow unceasingly, and each new grain of truth is packed, like radium, with whole worlds of light. the eclipses timed in babylon help us now to clock that gradual quickening of the moon, ten seconds in a century. who that wrote on those clay tablets could foresee his gift to future ages; dreamed that the groping mind, dowered with so brief a life, could ever range with that divine precision through the abyss? who, when that good dutch spectacle-maker set two lenses in a tube, to read the time upon the distant clock-tower of his church, could dream of this, our hundred-inch, that shows the snow upon the polar caps of mars whitening and darkening as the seasons change? or who could dream when galileo watched his moons of jupiter, that from their eclipses and from that change in their appointed times, now late, now early, as the watching earth farther or nearer on its orbit rolled, the immeasurable speed of light at last should be reduced to measure? could newton dream when, through his prism, he broke the pure white shaft into that rainbow band, how men should gather and disentangle ray by delicate ray the colours of the stars,--not only those that burn in heaven, but those that long since perished, those vanished suns that eyes can still behold, the strange lost stars whose light still reaches earth although they died ten thousand years ago. here, night by night, the innumerable heavens speak to an eye more sensitive than man's, write on the camera's delicate retina a thousand messages, lines of dark and bright that speak of elements unknown on earth. how shall men doubt, who thus can read the book of judgment, and transcend both space and time, analyse worlds that long since passed away, and scan the future, how shall they doubt his power from whom their power and all creation came?" i think that, when the second herschel tried those great hexameters in our english tongue, a nobler shield than ever achilles knew shone through the song and made his echoes live: _"there he depicted the earth, and the canopied sky, and the sea-waves, there the unwearied sun, and the full-orbed moon in their courses, all the configured stars that gem the circuit of heaven, pleiads and hyads were there and the giant force of orion, there the revolving bear, which the wain they call, was ensculptured, circling on high, and in all his courses regarding orion, sole of the starry train that descends not to bathe in the ocean!"_ a nobler shield for us, a deeper sky; but even to us who know how far away those constellations burn, the wonder bides that each vast sun can speed through the abyss age after age more swiftly than an eagle, each on its different road, alone like ours with its own satellites; yet, since homer sang, their aspect has not altered! all their flight has not yet changed the old pattern of the wain. the sword-belt of orion is not sundered. nor has one fugitive splendour broken yet from cassiopeia's throne. a thousand years are but as yesterday, even unto these. how shall men doubt his empery over time whose dwelling is a deep so absolute that we can only find him in our souls. for there, despite copernicus, each may find the centre of all things. there he lives and reigns. there infinite distance into nearness grows, and infinite majesty stoops to dust again; all things in little, infinite love in man . . . oh, beating wings, descend to earth once more, and hear, reborn, the desert singer's cry: _when i consider the heavens, the work of thy fingers, the sun and the moon and the stars which thou hast ordained, though man be as dust i know thou art mindful of him; and, through thy law, thy light still visiteth him._ the end the egyptian cat mystery a rick brant science-adventure story by john blaine grosset & dunlap, inc., 1961 new york, n. y. all rights reserved _printed in the united states of america_ [transcriber's note: extensive research did not discover a u.s. copyright renewal.] [illustration: _the room had been searched inch by inch. someone wanted the cat!_] contents i the winston plan ii the egyptian cat iii cairo iv el mouski v sahara wells vi the cat has kittens vii the egyptian museum viii the midnight call ix the uninvited visitor x the great pyramid xi third brother smiles xii third brother stops smiling xiii the space mystery xiv the broad sahara xv the cat comes back xvi the howling jackals xvii ismail ben adhem xviii the fight at sahara wells xix the cat's secret xx the signal vanishes list of illustrations _the room had been searched inch by inch. someone wanted the cat!_ _a snub-nosed revolver was pointed at rick's midriff_ _hands pulled rick from the saddle_ the egyptian cat mystery chapter i the winston plan the date was december twenty-third. the time along the greenwich meridian, from which all world times are measured, was 8:15 p.m. at widely scattered points around the globe, four voices were raised simultaneously. even an experienced observer could not have found a connection between the four voices and what they were saying, yet each voice started actions that would soon be interwoven into a single pattern--a pattern of danger, adventure, and mystery that would culminate in sudden violence within sight of one of the seven wonders of the world. in chicago, it was 2:15 in the afternoon. at the edge of the city a man spoke into the telephone in the office of a small plastics factory. "the cat is ready," he said. in paris, a phone rang. the man who answered noted in the log that his overseas call had gone through at exactly 9:15 p.m. he picked up the phone and spoke crisply. "_monsieur l'inspecteur? ... _bien._ this is interpol. we have a relay for you from the united states. monsieur, this will please you--and it most certainly will amaze you. message begins..." in cairo, the time was 10:15 p.m. a famous egyptian astronomer walked into his office and called to his associate. "hakim! good news. he can come. now we can find out what that accursed hydrogen-line impulse means." on spindrift island, off the coast of new jersey, it was 3:15 in the afternoon. the island was quiet under a blanket of snow. the long, gray laboratory buildings, where so many dramatic scientific developments had taken place, were deserted. only in the homes of the scientists was there activity, and all of it was in preparation for christmas. in the big main house on the seaward side of the island, dr. hartson brant, director of the world-famous spindrift scientific foundation, walked to the foot of the stairs and called to his son. "rick, can you come to the library in five minutes? bring scotty with you." rick brant, a tall boy with light-brown hair and eyes, paused in his gift wrapping long enough to call an affirmative to his father, then he made sure don scott, whose room was next door, had heard the summons. scotty had. he came through the connecting door. "what's up?" "don't know. maybe dad has some christmas chores for us to do." scotty, a big, husky boy with black hair and brown eyes, was an ex-marine who had originally joined the spindrift group as a guard during the adventure of _the rocket's shadow_. since then, he and rick had become the closest of friends, and the brants had accepted him as a full-fledged member of the family. "i'm willing, whatever it is," scotty told rick. "i'm so full of yuletide spirit i may bust a seam from sheer joy." rick grinned. he felt exactly the same way. he continued wrapping the present for his sister barbara, a pretty girl a year his junior. barby had a definite talent for sketching and painting and rick had bought her a complete artist's kit, hoping it would encourage her natural skill. "she'll be tickled pink," scotty remarked. "come on. let's go down." "go ahead. i'll be right with you." rick finished taping on a spray of evergreen, then he carefully put the present out of sight under his workbench. barby's lively curiosity was subdued at christmas time, but it was better not to take chances. he surveyed the bench to see if he had left anything out. usually it was cluttered with apparatus, tools, and parts, because rick was an inveterate experimenter, but it was clear now, in preparation for the holiday. he walked down the corridor to the stairs, smiling to himself. christmas at spindrift was fun. the entire scientific staff and their families joined in, first in cutting their own trees from the stand of spruce at the back side of the island, then in decorating the big tree in the brant library. on christmas eve there was a yule log to be brought in and presents to be exchanged, although the brants waited until morning to open their gifts to each other. hartson brant and scotty were waiting in the library, standing before the great fireplace in which logs crackled merrily. seated in the leather chair next to the christmas tree was parnell winston, one of the leading staff scientists. winston was a big man, with jet-black curly hair and great bushy eyebrows that hid merry blue eyes. he was an expert in cybernetics, the science of electronic computer design, and his contributions to the theory of computer operations, and to advanced electronic control systems, were known to scientists around the world. winston had originally joined the staff to supervise the design and construction of a "thinking machine," the tractosaur. hartson brant, an older version of his son, greeted the boy. "come in, rick. parnell, the floor is yours." winston motioned the boys to chairs. "sit down. i called this meeting to make a proposal. but first, how are your bank balances? fat or thin?" rick considered. most of his income, including his small salary as a laboratory assistant, went into his education fund. however, the salary he had earned for working at the nevada rocket base during _the scarlet lake mystery_ had been put into his "ready" fund. "i'm in good shape," he said, and scotty echoed him. "fine. now, the egyptian astronomical society has just finished constructing a new radio telescope. it's a first-rate instrument from which we expect great things. your father and i were in at its birth, so to speak. we consulted on the initial designs during a meeting of the international astronomical union." rick knew that was one of the many world-wide private scientific organizations operating under the international council of scientific unions. he also knew of the growing importance of radio astronomy, but he hadn't known the egyptians were in on it. "apparently some unusual trouble developed during the tuning of the instrument," winston went on. "earlier this afternoon i had a phone call from cairo, and a request to help our egyptian colleagues iron out the bugs. i accepted." rick sat upright in his chair. winston going to cairo? how did this concern scotty and him? "my proposal is this," winston concluded. "the egyptians are short of technicians and we may need help. i'll leave the day after christmas, returning within ten days. if you two can pay half your expenses, and help me half the time, i'll take you with me." both boys jumped to their feet. rick looked anxiously at his father. hartson brant smiled. "according to parnell's schedule, you'll be back just in time for school at the end of the holidays. _if_ you want to go, of course." rick let out a wild yell of exuberance that brought his sister barby running to the library. she looked at the group with wide eyes. "rick! was that you?" he grinned at her. "it wasn't a wounded buffalo, sis. guess what? we're going to egypt!" barby's pert face lengthened. "i don't suppose i can go, too?" parnell winston walked over and ruffled her blond hair. "not this time, barby. but i'll make you a promise. the next field expedition under my supervision will include my wife, you, and jan miller." the prospect of an expedition that included jan, daughter of one of the staff physicists and her dearest friend, cheered barby at once. "i don't suppose you could promise to leave rick and scotty at home?" she asked. "can't promise." winston chuckled. "we might need them to carry your luggage. girls can't travel without a dozen suitcases each, i'm told." the scientist turned to the boys. "start reading up on the country, and i'll arrange for you to get some additional background by meeting some egyptians. it happens that an egyptian physicist is arriving in new york today for a lecture tour of american universities. there's a reception for him tomorrow. we'll drive to new york. you can meet him and some of his countrymen, and we'll go to the consulate to obtain visas. are your passports and health cards up to date?" fortunately, all was in order because the boys had spent a part of the summer in the sulu sea region, where they had helped to locate and rescue two staff scientists. barby asked wistfully, "couldn't i meet some real egyptians, too?" as scotty had once said, if barby ever got wistful while fishing, the fish would knock themselves out trying to climb into the boat to cheer her up. winston replied quickly, "no reason why not. i'll check with my host, but i'm sure it's all right, so you can plan to come with us." rick's eyes met scotty's. he shrugged. he was glad in one way that his sister could go, because he always hated to have her unhappy about being left behind. on the other hand, barby was unpredictable. he couldn't be sure of what she might do or say, but he could be certain her curiosity and enthusiasm would stir up something. if rick had been enough of a prophet to see all the events his pretty sister's helpfulness at the reception would get him into, he would have handcuffed her to the christmas tree before ever allowing her off spindrift island. chapter ii the egyptian cat the reception for dr. hayret ahmed was at the home of an egyptian importer named mohammed bartouki. barby, the boys, and winston rang the bell of a brownstone house on new york's upper east side promptly at noon. winston had checked with his host by phone, and his request that he be allowed to bring his young associates to meet bartouki had been met with enthusiastic pleasure. mohammed bartouki had assured the scientist that he would look forward to meeting the young people of dr. hartson brant's household. the door was opened by a figure right out of _the arabian nights_, or so it seemed to the young people. the doorman was a huge negro dressed in flowing red trousers that tucked in at the ankles. his sandals turned up in points at the front, persian style. an embroidered vest set off a loose white silk shirt, and on his head was a red fez, shaped like a section of a cone, slightly less in diameter at the top than at the bottom. "please come in," he requested. his voice was accented. rick saw that he had two horizontal hairline scars on each cheek. the man took their coats, giving barby a courtly bow. "dr. bartouki asks if you will please join him in the salon. it is straight ahead." as they walked down the carpeted hall barby gave winston a smile of sheer delight. "he's right out of a movie," she whispered. "even to the fez and the scars on his cheeks." winston smiled back. "in egypt a fez is called a _tarboosh_. the scars mean he is a sudanese, from the country south of egypt. i agree he's a very picturesque type. i suspect bartouki dressed him up for effect. it's a common practice." "what's bartouki a doctor of?" rick asked. "i don't know. law or something similar, i imagine. he's not a scientist or medical doctor." mohammed bartouki himself came to meet them. he was a round little man, scarcely taller than barby, with twinkling eyes behind horn-rimmed glasses. he was dressed in an ordinary business suit. "my dear dr. winston, how nice of you to come. and these are your young friends?" winston introduced the young people. rick found his hand captured in a warm, firm grip. "welcome, welcome," bartouki said, beaming. "we will have an opportunity to talk about your trip to my country as soon as these scientists turn the conversation to some matter of science we do not understand." he smiled at winston. "you see, i know you professional people. the nationality does not matter. put two of you together and the conversation at once turns to some development a poor merchant cannot possibly comprehend. that is why i am glad you brought miss barbara, and rick and scotty, as you called them, if i may be so familiar. at least i can talk with them." rick could see that barby was charmed by the little merchant, and he could understand why. bartouki radiated warmth and enthusiasm. in a moment the four spindrifters were being introduced to dr. hayret ahmed and a bewildering assortment of people. evidently they were all scientists of different nationalities, except for two officers of the united arab republic consulate. rick recognized a few of the names, and found he knew one or two of the americans. true to bartouki's prediction, the talk turned to scientific subjects within minutes. rick followed the conversation, which was about a new development in the capture and study of free radicals, but only for a few minutes. the scientists were over his head in short order. scotty chuckled. "i always thought a free radical was a political bomb thrower out of jail." "it's a highly energetic chemical particle," rick said. "that's nice," barby said. "only i'd rather talk with dr. bartouki than discuss energetic chemicals." the merchant arranged things very smoothly. he announced that he would not dream of allowing protocol to interfere with such a fascinating conversation, and put the scientists together at one end of the table. the officers from the consulate, evidently in deference to the distinguished egyptian scientist, continued to listen closely to the talk, even though rick was sure they didn't understand a word. the three young people found themselves free to talk with their host, and the boys at once began firing questions. bartouki described cairo and promised that he would present them with guidebooks to be read on the way over. he told them about things to do in the ancient city, and listed places that were "musts" for tourists. they included the step pyramid at sakkarah, the egyptian museum, the mosque of sultan hassan, and the mosque and college of el azhar, founded in the ninth century. "of course you will see a great deal of the sphinx and the pyramids at giza, since our new radio telescope is nearby. but most of all, you must see el mouski." "what is that?" rick asked. "it is the cairo bazaar. there are several sections, known as _sooks_. they have names like khan el khalili, ghooriyeh, sagha, sook el nahassin, and so on, but the principal one is mouski." "spell it for me," barby pleaded. bartouki smiled. "what you ask is difficult. we use a different alphabet, so there is no exact equivalent, only what is called transliteration, which uses phonetics. so the bazaar can be mouski, muski, mosky, mouskey, or anything else that sounds the same. even for giza, where the pyramids are, there are many spellings." "i wish you'd tell my english teacher that." barby sighed. "i think my way of spelling is just as good as hers." bartouki and the boys laughed sympathetically. the little merchant said, "whatever the spelling, el mouski will fascinate you. many things are made there especially for tourists. some of the workmanship is excellent, and the prices are very low." "we haven't had much luck with bazaars that cater to tourists," scotty replied. "we prefer markets where local people buy, because the things are more authentic." bartouki chuckled. "that is wise, in most countries. but consider. the attraction for tourists are things that are clearly egyptian in origin, no? such things vanished from all but our museums some years ago. you could not buy a genuine egyptian tapestry, or a stone carving from a tomb. such things are beyond price. they are national treasures. but you can buy very attractive and authentic reproductions." "the people of cairo wouldn't want reproductions, would they?" barby asked. "so they have to be made just for tourists." "and for export," bartouki added. "i import them myself for a few american shops. after lunch i will show you samples and you will see." it seemed reasonable to rick when he thought about it. genuine egyptian things simply were not obtainable. "what else is made for tourists?" he queried. "many things, of gold, silver, and ivory. there are bags of camel leather that miss barbara would enjoy having. there are brass goods of all kinds, and copperware with a partial tin coating called washed tin." the conversation paused long enough for a few bites of lunch, then bartouki resumed. "we try to take good care of tourists in the united arab republic, both in egypt and in syria. for example, we license our guide-interpreters, who are called _dragomen_. there is also a special police force with no job but aid to tourists. and we are always looking for ways to improve our reproductions to make them more attractive and authentic. i will show you a new design." by the time luncheon had ended, the talk among the scientists had progressed to the basic theory of what physicists call "the solid state." even rick, with his rapidly growing background of scientific knowledge, could understand only fragments of conversation. "let them talk over their coffee," bartouki said. "they are enjoying it. we will retire to my den and i will show you examples from el mouski." the samples were everything bartouki had promised. there were wall hangings, beautifully made of tiny pieces of colored cloth appliqued on a natural-color fabric, bags and pouches of leather, leather hassocks, ivory carvings of ancient egyptian gods, inlaid boxes and chests, and dozens of both useful and ornamental utensils of brass, copper, washed tin, and ceramics. barby went into raptures. at every new item she urged rick to bring her one just like it. "i'll rent a jet just to carry my luggage," he said, grinning. "you've already ordered a ton, and i get only sixty-six pounds." bartouki came to his rescue. "let me show you a new tourist attraction. it just arrived by messenger this morning." he went to a cabinet, opened it, and produced a stone cat. it was about ten inches high, in a sitting position with its tail curled around to meet its feet. it was of sandy texture, reddish in color. "sandstone?" rick guessed. bartouki smiled. "i hoped you would say that. here. examine it." rick took the cat. he liked it very much. the design was clean and elegant, stylized after the egyptian manner. but it wasn't sandstone. it was heavy, but not heavy enough to be sandstone, and the sheen was not that of a mineral. whatever the material, it had been fashioned in one piece, probably cast in a mold. "i give up," he said. "what is it?" "plastic," bartouki replied, obviously pleased. "it did not come from egypt. it was made right here in america. in chicago, to be exact. it is what you call a prototype." "but it's egyptian in design," barby protested. she took the cat from rick and examined it. "yes, it is clearly an egyptian cat. the design came from egypt, but the cat from america. i have been working on this for months with a plastics company. now i have the model, and the method. we will reproduce these in quantity in cairo." "it's pretty heavy for plastic," rick commented. "true. we put a piece of lead in the middle of the casting. you see, it looks like stone, and the buyer will expect it to be heavy. so, for psychological reasons, we give it weight--only not so much that it becomes a problem to carry." "you certainly have it worked out," scotty said admiringly. "but why a cat? why not a ... a camel?" "we have camels of camel leather, brass, and wood. but we do not have a good cat. you see, the cat is important in egyptian history. there was even a cat goddess of the upper nile kingdom, called bubaste. in the ancient tombs there are sometimes mummies of cats. some cat lovers think our land first developed the domestic strain of cat. so we believe tourist cat lovers should have an authentic reproduction of one. this particular cat is a faithful copy of an antique, which i am fortunate to own." "what will you do with it now?" barby asked. "send it to my associate in cairo, as soon as possible. i would like to airmail it right away, but you americans overload the mails at christmas, so it would be safer to wait. next week i hope to send it with full instructions, hoping to get production started in time for the big tourist season. i wish it could go sooner. it is needed." barby said impulsively, "rick leaves the day after tomorrow. he could take it for you. couldn't you, rick?" there was no reason to refuse. it was certainly a worthy project, and bartouki had been generous in answering their questions. "be glad to," rick said. the merchant's eyes lighted. "it would not be an imposition?" "of course not. i can put it right in with my clothes. i have plenty of room." "believe me, i will be in your debt. and so will my associate, ali moustafa. you will like him. he is a great, jolly man, three times my size. if he had a beard, he would resemble your santa claus. and he will insist that you accept some token of his appreciation. i will send the instructions separately, so you need not bother with the technical reports." "i couldn't accept a gift for such a little thing," rick protested. he looked at the cat, now in scotty's hands. it was a handsome little statue. "ali moustafa is a hard man to refuse," bartouki said. "you should not deprive him of the pleasure of making a gift. but i will not press you. it will be between you and him. you are quite sure it will be no trouble?" rick's words would return to haunt him during the days ahead. he said blithely, "no trouble at all." chapter iii cairo the jet descended smoothly over the desert on the approach to cairo international airport. rick leaned toward the window to watch for the first sign of a runway. in the distance he could see the valley of the nile river, a great green swath which cut through the tan desert wastes. "excited?" scotty asked. rick had to grin. "excited? why should i be excited? a trip to egypt is an everyday event for me. stop asking silly questions and look at the scenery." "i would," scotty told him, "only somebody's head is in the way. i won't exactly say it's a fathead, but it's too thick to see through." "real subtle. i like the way you give delicate hints." rick moved back so scotty could see, and watched as the great plane dropped toward the desert, then touched down and sped along modern runways to the administration building. two egyptians were waiting as winston and the boys walked down the stairway, and the scientist at once hurried to greet them. obviously the three were old friends. winston introduced the two boys. the older of the two egyptians was dr. abdel kerama. he was a tall, gray-haired man of distinguished appearance. rick thought that in traditional desert costume he would look like the head sheik of all the desert tribes. the younger egyptian was dr. hakim farid, a youthful, clean-cut man with an attractive smile. rick knew from winston's advance briefing that these were the two leading radio astronomers of the united arab republic, and that both had international reputations in the field. the egyptian scientists made the boys feel at home right away. dr. kerama took scotty and winston by the arms, and dr. farid fell in step with rick as the group walked toward the administration building. "we're glad you could come," farid said in excellent english. "we'll try to make your visit interesting." rick thanked him. "i don't know whether we'll be of much use, but we're willing to do anything we're told. all we ask is a little chance to see your country." "you'll have every chance," dr. farid told him. "before there is any work for you, parnell will have to do a pretty thorough analysis of data we've collected. it's a problem that has us ... what's the american expression? buffaloed?" "that's it," rick agreed. "what kind of problem is it?" "it's what you might call very strange behavior on the part of a hydrogen-line impulse we picked up while calibrating our receiver. are you familiar with radio astronomy?" "not very," rick admitted. "i tried to read some of the current literature when i found we were coming, but most of it is over my head." "then i won't bore you with a technical discussion. briefly, the noise emitted by hydrogen gas in space is very important to us in our analysis of the nature and distribution of matter. this radio noise is, of course, random. usually when we are examining a hydrogen source we get pretty continuous and regular signals. if we could hear it, there would be a sort of hissing noise. do you follow me?" "so far." "good. our problem is that we are picking up impulses. you might even call them signals. they are on the frequency of neutral hydrogen, but it's hard to believe they're natural in origin. we've about concluded that somehow our amplifier system is modulating the incoming hydrogen signal from the antenna. the trouble is, we can't locate the cause." "is that why you called dr. winston?" rick asked. "yes. he has a reputation for finding bugs in electronic circuits. if he can find this one, we'll be tempted to reward him with a pyramid or something appropriate." rick saw the twinkle in dr. farid's eyes. "better not make it a pyramid," he said hastily. "his luggage is limited to sixty-six pounds. they might not let him on the plane with it." "a happy thought," dr. farid said seriously. "you have saved us from possible embarrassment. it would be useless to give him a pyramid when his weight limit is thirty kilos, as we call sixty-six pounds." rick chuckled. one reason he so enjoyed his association with scientists was the dry sense of humor most of them seemed to share. they reached the administration building and started through the formalities of customs and immigration. the americans had filled out customs forms and currency declarations on the plane, and in only a short time the formalities were over and their admission into the united arab republic was official. the customs inspectors hadn't even asked them to open their luggage. the trip from the airport took over an hour. it led through heliopolis, city of the sun, the first capital of a united egypt. the land had been governed for over a thousand years from heliopolis. but that, as dr. kerama explained, was over four thousand years ago. rick was awed. coming from a new land where a hundred years seemed a very long time, the antiquity of egypt stirred his imagination. but there was little that seemed ancient in modern heliopolis. there were attractive, modern apartment houses, new public buildings, and rows of trees carefully trimmed into perfect green cylinders. the entry into cairo itself was through rows of tall wooden or brick structures, along streets traveled by everything from the latest european cars to plodding donkey carts. the people were dressed in a variety of costumes, from suits and dresses that would have been suitable in new york, to traditional arab dress with flowing robes and the cloth headdress that is held in place by a band or roll of fabric around the head, just above the eyes. the car passed the railroad station and the great statue of rameses the second, pharaoh of egypt. the nile came into view, and farid pointed out the row of hotels on the other side. the shepheard's and the nile hilton flanked the older, victorian bulk of the semiramis, where they would stay. they sped across a bridge, entered a plaza full of honking horns and speeding cars, then moved to the comparative quiet of a street along the nile embankment to the hotel. uniformed attendants came running for their bags. the group entered the lobby, and rick looked around with interest. the semiramis was big, with lofty ceilings and chandeliers. the walls were decorated with scrolls and tapestries. the rugs had once been red. there was a kind of eighteenth-century grandeur about it, even though it had turned a little shabby over the years. the formalities of registration were completed, then the americans went to the cashier and exchanged dollars for egyptian pounds and coins in units called piastres. they carefully put away their receipts for the exchange, since currency control in the country was strict. "go ahead," winston told the boys. "farid and kerama will come with me. i want to start talking over this interesting problem of theirs, and i imagine you want to rest." rick did not feel in the least like resting, but made no comment. he and scotty got into a tiny, ornate elevator cage with walls of gilded-iron lattice. there wasn't room for the porters with their bags; they ran up the stairs while the boys rode with the smiling elevator operator. it wasn't a fast ride. "climbing rate, one hundred feet per minute," scotty said. rick grinned. they were let off at the third floor, and weren't in the least surprised to find the porters waiting for them. they followed the men into a room that made them stop short with amazement. the entrance to the hotel and the lobby had been big, but the room was enormous, spacious, and very tastefully furnished, european style. "as big as grand central station!" scotty exclaimed. rick echoed, "we'll rattle around in here like a pair of pebbles in a fifty-gallon tank." the bath was larger than most american hotel rooms, with a twenty-foot ceiling, and the closet would easily have accommodated a king's wardrobe. rick thought that maybe it had, in times past. he tipped the porters and closed the door behind them, then motioned to scotty. "go on down to the other end of the room and shout. i want to see if i can hear you." scotty started to oblige, grinning, then turned and called, "come look at this view!" he had discovered that the french doors at the front of the room opened onto a tiny balcony that overlooked the nile. the great river was only the width of a narrow street away. sailing gracefully along with brown sail set was a nile boat. the bridge they had crossed was directly ahead of the boat, and rick looked for the drawspan through which it would pass. there was none! "he'll crash right into the bridge!" rick exclaimed. "why doesn't he correct his course?" "rudder stuck, maybe," scotty offered. "but why doesn't he drop the sail and try to lose headway?" they watched helplessly as the boat, fully fifty feet in length, bore down on the bridge. there were many people in sight, and a steady line of cars crossing the bridge, but no one paid the slightest attention. scotty grabbed rick's arm. he started to laugh. "look at that mast!" fascinated, rick watched as the huge mast dipped slowly backward, triangular sail and all, until it lay nearly flat on the deck. the boat slipped under the bridge with room to spare. on the other side, the mast slowly went up to its normal rakish position again, the sail filled, and wind and current bore the boat steadily down the nile. "not exactly the way we'd do it," rick said with a grin, "but pretty effective." it was a reminder that they were in a new land, where customs were strange to them. "you learn something new every day," scotty agreed. "let's unpack, then go visit the city." "better wait and see what winston has in mind for us," rick cautioned. he began to stow his clothing in one of the big dressers. he lifted a shirt, and stared down at the egyptian cat nestling among his t shirts. "tell you what, if winston doesn't need us, let's deliver the cat. we can see some of the city coming and going." when their clothes were stored, they washed away the grime of travel and rick called winston's room. hakim farid answered. "don't think we've forgotten you," the young radio astronomer said. "but parnell and kerama wasted no time in getting down to business. i doubt that you could interrupt long enough to get a sensible answer. do you have any plans?" "we have an errand at el mouski," rick replied. "would it be all right for us to go?" "no reason why not. you'll need a car. i would offer you mine, except that you have no local license. you could take a taxi, but a licensed dragoman would be better. suppose i suggest one with a car?" rick remembered that bartouki had told them a dragoman was a guide-interpreter. "that would be very good of you," he replied. "all right. i will send one i know, or a friend of his if he is not available. wait in your room and he will come for you." rick thanked farid and hung up. he reported the conversation to scotty. "first time i've ever had a guide in a city," scotty said. "makes me feel important, like visiting royalty or something. couldn't we just get a map instead?" "we'd still need a car. might as well get one with a built-in talking map. besides, i like the idea. i want to be escorted like a visiting prime minister." there was a paper laundry bag in the closet. rick used it to wrap the cat against possible scratches. scotty took the few moments to get some cards written, to which he signed both their names. there was a polite knock on the door, and rick opened it. he gaped at the sight of what was apparently their dragoman. he was a magnificent figure in blue pantaloons and short red jacket. he had an engaging black face marred by three straight hairline scars that ran in a diagonal across his cheeks. "have honor to present me," the figure announced formally. "name of hassan. to serve you." "come in, hassan," rick invited. "are you the dragoman dr. farid sent?" "is same, _ya sidi_. to serve you." rick introduced himself and scotty. he inspected the guide with interest. hassan was young, with a friendly white-toothed smile. the scars identified him as sudanese, but rick didn't know enough about the markings to tell what part of the sudan he came from. a different part from bartouki's servant, though, because the scars were at a different angle, and hassan had three on each cheek. rick's quick imagination could picture the sudanese in a different setting, with scimitar in hand, guarding the palace of a legendary sultan. it was hard to imagine him in the prosaic role of a guide. rick resolved to take a picture for barby's benefit. a blackamoor warrior right out of the tales of scheherazade! that was how she would see it. the boys shook hands with the dragoman, and rick saw that he responded to their obvious friendliness. the costume was an odd one, though. rick hadn't seen any like it on the street, and he wondered if hassan wore it for effect, since most of his customers probably were tourists. later he found that the guess was right. "where you like to go?" hassan asked. scotty spoke up. "you know el mouski?" hassan's face split in a wide grin. "who does not?" "that'll teach me to ask silly questions," scotty said ruefully. "like asking a new yorker if he ever heard of central park." the boys walked downstairs with hassan, since it was faster than taking the elevator, and went to the alley behind the hotel where he had parked his car. the car was a small foreign sedan of a make neither boy had ever heard of. apparently hassan also used it as a taxi, because the front passenger seat was taken up mostly by a taxi meter. rick showed hassan the address in his notebook. the guide shook his head. "please, you read." rick looked at him with astonishment. a guide who couldn't read? but apparently it was so. "it is the store of ali moustafa," he explained. hassan shrugged. "i do not know it. but it can be found. _enshallah._" although the boys did not recognize it then, the word was a common expression meaning "if god wills it." they would learn it, though, and with it other arabic words, including _zanb_, _dassissa_, and _khatar_--or, in english, crime, intrigue, and danger! chapter iv el mouski hassan drove out of the hotel alley into a chaos of horns, pedestrians who flirted with sudden death, wildly maneuvering cars, and donkey carts that always seemed on the verge of being hit by an accelerating truck. it was a normal day in cairo traffic. the boys watched with mixed fear and amazement--fear that hassan would hit someone and amazement that he didn't. time after time he bore down on a slow-moving egyptian and rick's heart leaped into his throat until collision was averted by some miracle or other, usually a wild, record-breaking leap by the pedestrian. the trip from the airport had been along streets that formed a kind of throughway, but in the city itself, the traffic was the kind that would send an american traffic cop screaming for the riot squad. here, no one seemed to think anything of it. the boys relaxed a little as it became clear that hassan knew what he was doing. his driving was perhaps a shade more careful than that of most drivers. once, as he sped down a crowded, narrow street at forty miles an hour, horns blasted behind them. rick turned, but could see nothing wrong. he asked, "why all the honking, hassan?" "they want we go faster," the dragoman said. scotty laughed. "might as well relax. this is the slow, sleepy pace of the middle east we used to read about." rick laughed with him. he had seen hectic traffic before, but nothing to compare with cairo. this wasn't traffic. it was some kind of wild contest with no rules and only survival as the winner's prize. "any number can play," he muttered. he tried to pay attention to signs, but they were in arabic script. he saw that modern cairo was giving way to the older city. the buildings were smaller, more closely spaced. most were of wood, but a few were obviously of ancient stone. in this part of the city, merchants displayed their wares on the sidewalks in front of cubicle-sized stores. then, with a suddenness that threw them forward, hassan pulled into a parking place, jammed on the brakes, and killed the motor. "we walk now," he told them. "street too small for car." rick could see only narrow alleys. if they were the streets hassan meant, walking was the only possible means of transportation. in the square where hassan had halted were dozens of merchants, some with their wares in carts, others carrying them on their backs. a rug merchant approached and hassan waved him off. "come. el mouski over there." he pointed to a narrow alleyway. [illustration] the boys followed, eyes taking in the sights, smells, and noises. merchants hawked their wares with raucous cries, charcoal braziers smoked under assorted foodstuffs, and the air was redolent with the odors of food, people, and the accumulated living of many centuries. in the alley were shops, closely packed, some little more than a doorway wide and others of quite respectable size. a few even had glass windows with displays. there were textiles, foodstuffs, tinned copper, brass, leather goods, inlaid work, rugs, shoes of strange designs, clothing, and a variety of antiques. hassan stopped before a cubicle crowded with interesting brassware and spoke in arabic to a dark man with tiny spectacles. rick thought he heard the name of ali moustafa. he waited while the merchant replied at length, with much waving of the hands as he outlined the path to the establishment. "i know now," hassan informed them. "we go." rick and scotty fell in step with the guide. in many places the alleys were under roofs or wooden awnings. in other places the buildings were so close together that the three walked in single file. rick could see that daylight seldom reached the bottom of el mouski. he moved aside to make room for a donkey which carried huge jars. merchants beckoned to the boys, promising low prices and goods of superb quality, but hassan waved them off. occasionally a beggar approached, but the boys were surprised by the small number of mendicants. the path passed from alley to alley, past dozens of shops. rick saw a few tourists, but the tourist season was still weeks ahead and most of the people were egyptian. a little egyptian boy with a dirty face called, "yonkees! 'ello!" the boys returned his cheerful grin. "this is a good-natured crowd," rick commented. many of the dark, semitic faces greeted them with cordial smiles and a half-salute of welcome. "friendly people," scotty agreed. "how far, hassan?" "two streets. soon." the dragoman turned a corner, led them straight ahead for a few hundred steps, then turned a second corner. he pointed. diagonally across the alley was a large store with display windows. a sign over the door carried the name ali moustafa surrounded by arabic script. "we'll get rid of the cat, then do some shopping," rick said. "i'm anxious for a closer look at some of these shops. how about you?" "ali moustafa's seems pretty good to me," scotty replied. "look at that stuff." he pointed to leather goods displayed in one window. "it's beautiful. go on in and deliver kitty while i see what some of these things are." "i tell you," hassan offered. "then i help bargain so prices be low. no bargain, prices too high." rick walked in through the open door, his eyes taking in the amazing collection of stuff sold by ali moustafa. the store was a big one, especially compared with most in the bazaar, and there were several clerks. the walls were lined with shelves that held copperware, brassware, silver, and inlaid boxes. he saw rolls of tapestries, collections of brass camels and donkeys, and glassed-in cases of jewelry. crowding the floor space were huge vases of brass or pottery, camel saddles, metal trays on low stands, and huge leather hassocks. the clerks eyed him with interest, then all eyes focused on the package under his arm. for a moment rick felt a current of tension run through the store, but he dismissed it as imagination. he walked toward the rear counter, trying to identify ali moustafa, but none of the clerks fitted the description bartouki had given. he addressed his question to the clerk behind the rearmost counter. "is mr. moustafa here?" the clerk's dark eyes flickered, and his face became expressionless. "please to be seated. i will get him." the clerk vanished through a curtained door at the rear of the store, and rick turned. he was sensitive to impressions, and he was again conscious of the tension. as he turned he saw that all the clerks were watching him, their faces impassive. his eyes went to the front of the store. scotty was with hassan in the doorway, discussing some object in the display window. a voice spoke from behind him. "you wish to see me?" rick turned. the newcomer was a tall, well-built egyptian with glossy black hair and a military mustache. unblinking black eyes met his gaze, and there was no hint of welcome in them. "are you ali moustafa?" rick asked. the man bowed a quarter of an inch. "at your service," he said. rick didn't know what to say. bartouki had described a huge, jolly fat man, like santa claus without a beard. this man was big, but not huge, not fat, and definitely not jolly. for a moment rick hesitated, then asked, "is there another ali moustafa in the bazaar?" the black eyes locked with his. "there is no other. i am the only ali moustafa. and you? if you are mr. brant from america, i have been expecting you. bartouki said you would deliver a package. is it the one under your arm perhaps?" rick didn't like this at all. even if the description had been exaggerated in some respects, this cold conversation was scarcely a cordial welcome. yet, the man knew about the cat, and about bartouki. something was wrong. he wanted to deliver the cat as he had promised, but he had no intention of turning it over to the wrong man. "i have a package," he returned evenly. "i'm sorry it can't be delivered now. the man who receives it will have to identify himself without question as the proper ali moustafa." the man shrugged. "you came to my shop. the sign tells you who i am. there is no other ali moustafa. so, i will accept delivery of the cat, if you please." rick shook his head. "sorry." the man spoke in arabic and took a step forward. sensing movement behind him, rick whirled. the clerks were moving to block his way! rick reacted with lightning speed. he yelled, "scotty!" scotty sensed the urgency of the call and jumped into the doorway. rick lifted the egyptian cat and rifled a pass through the closing ranks of clerks. scotty snatched the cat out of the air. rick followed through with a battering charge that sent a clerk caroming into a stack of copper jars. they went down with a clatter. another clerk reached out and rick gave him a straight arm that cleared the way long enough for a jump to the outside. "run!" he yelled. hassan had been standing with mouth open, astonished at the proceedings. now, as a clerk charged through the door, the dragoman flung himself sideways in a beautiful body block that sent the clerk back into the store with a crash. then the three were rounding the corner at top speed, pushing through the people in the street. from behind them came a shouted command in arabic. a figure in a long, dirty robe stepped into scotty's path and grabbed for the cat. the boy tossed a lateral pass to rick, who tucked the package under his arm. scotty's hand lashed out and his open palm caught the arab under the chin. the man lifted inches into the air and his head thudded audibly against a brick wall. he lost all interest in the proceedings. hassan led the way like a charging lineman, with rick in his wake. scotty fell back a few paces to prevent attack from behind. but in spite of a few yells from the rear, no one else menaced them. the people of the bazaar obviously were curious, but not involved. rick had a fleeting thought that a pair of obvious foreigners running at top speed through a department store at home would arouse some curiosity, too. he grinned, in spite of his bewilderment. then they were at the car. hassan wheeled the little sedan around in almost its own length and charged through the crowded streets like a miniature juggernaut, heading back to the hotel. * * * * * a short time later over _cafã© au lait_, part coffee and part hot milk, the boys and hassan held a half-angry, half-amused post mortem. there had been no opportunity in the car for real conversation because of the sheer adventure of rocketing through impossible traffic at equally impossible speed. rick had reported briefly to scotty, and that was all. scotty took a sip from his steaming cup and turned to hassan. "you ever play football?" hassan stumbled over the word. "footsball? what are footsball?" "never mind." scotty grinned. "the way you took that clerk out, i thought you might have played blocking back for the green bay packers." the dragoman's bewilderment deepened. rick came to his rescue. "football is an american game, hassan. it is rough. the green bay packers is the name of a famous professional football team." "one thing is for sure," scotty offered. "the clerks didn't know football. that flat pass you threw was good for plenty of yardage." "it made a touchdown," rick pointed out. he changed the subject. "look, what went on in that store, anyway? i don't know who the big man was, but he wasn't ali moustafa. at least he didn't come close to bartouki's description." "why didn't you give him the cat, anyway?" scotty asked with a grin. "afraid a brand-new mystery might end without you getting a piece of it?" rick grinned back. "not a bad idea, now that you mention it. i didn't think of it at the time. the only thing i knew for sure was that i wasn't going to hand over any helpless little pussycat to a guy with eyes like that. he'd mistreat it." "uhuh. only, now what do we do with the cat?" "give it to the right ali moustafa," rick said. "there must be a right one somewhere." scotty waved his arm in a gesture that took in all of egypt, half of the sudan, and most of libya. "help yourself. i'll bet there are ten thousand ali moustafas around. how do you find the right one?" rick didn't try to answer. instead, he asked hassan, "could there be another ali moustafa in el mouski?" the guide shook his head. "i ask my friend when we stop. he say there is only one, and he tell me how we get there." rick's brows furrowed. "then that must be the shop bartouki meant. only where was big, fat, jolly ali moustafa? or could i be wrong about the description?" scotty was definite. "not a chance. i remember the description the way you do. either bartouki didn't know his own partner, or the man you saw was not ali moustafa--unless he took off weight and shaved his beard. and changed his disposition in the bargain." "which brings us back to the question before the house. what do we do with the egyptian cat?" "give it to hassan," scotty suggested with a smile. the dragoman's pleasant black face assumed an air of great sadness. "cat's nice," he said. "but no can take. too much cost for food." rick smiled at the joke, then suddenly he realized hassan was not joking. he was genuinely sad! he took the package from his lap and held it up. "hassan, what do you think is in here?" the dragoman shrugged. "you say cat. i believe." scotty asked incredulously, "didn't you think carrying a cat wrapped in paper was pretty strange?" hassan smiled apologetically. "americans many time do thing i not understand." rick choked back laughter with a heroic effort and almost strangled. scotty found a handkerchief and blew his nose violently. "pretty strong coffee," rick managed finally. scotty nodded, struggling to keep a straight face. neither of them wanted to risk hurting the guide's feelings. "hassan," rick said at last, "even american science couldn't keep a live, wide-awake cat quiet in a paper parcel. this cat is a model, a statue. you see?" for an instant hassan stared, then he rocked back, his white teeth flashed, and he shouted with laughter. the boys broke down, too, and in a moment the entire patronage of the coffee shop was staring at the three idiots who roared with unrestrained laughter in public. such behavior in americans was to be deplored, perhaps, but understandable. but a licensed dragoman ... incredible! when they had quieted down, rick summed it up. "well, hassan knows what's in the package now, but that's the only new bit of information any of us has. we still don't know exactly what happened in the bazaar, or why. and we don't know what to do with the cat." he felt the cat through the heavy paper, as though to reassure himself it was there. suddenly he didn't want to get rid of it quite so urgently, and inwardly he laughed at himself. a mystery was one thing he couldn't ignore. "i hope i'm wrong," he concluded thoughtfully, "but i have a hunch this little plastic feline is going to be more trouble than the liveliest real cat you ever saw!" chapter v sahara wells hassan arrived during breakfast on the following morning. his colorful costume had given way to european clothes, except for a tarboosh. he wore a topcoat. at rick's invitation he joined the boys on the balcony overlooking the nile, and accepted the offer of coffee. rick went to the novel push-bell system which had three buttons identified by pictures. one was a porter, another the room maid, and the third a waiter. the little drawings were for the benefit of strangers who knew neither arabic nor english. rick rang for the waiter and ordered more coffee and a cup for the dragoman. hassan shed his topcoat and grinned at the boys. "cat catch mouse last night?" "no mouse," scotty replied. "the cat just caught some sleep. and so did we." hassan puzzled out the reply, then smiled his appreciation. rick thought that the cat hadn't even caught any interest--at least from the scientists. at dinner he and scotty had described the incident at el mouski to winston and the egyptian scientists. the scientists had only one suggestion, to the effect that perhaps the boys' imaginations had run away with them. it was obvious that the scientists were far more interested in the problem of the radio telescope than in listening to tales of wild adventure in the bazaar, so the boys let the matter drop. they had excused themselves immediately after dinner and turned in, tired from the long plane trip and the day's excitement. rick had gone over the events at the bazaar a dozen times. he had compared notes with scotty on what bartouki had told them. clearly, something was pretty strange about the whole affair. it was simply inconceivable that bartouki would have given an inaccurate description of ali moustafa, so the man in the store had not been bartouki's partner. yet, he had known about the cat, and had called rick by name. who was he? and where was the real ali moustafa? there were no answers, at least for the present. but rick didn't intend to give up. he motioned to hassan's coat. "is it cold out today?" "yes. good you wear coats when we go out. later it will be warm, then cool again when sun goes." the boys had decided to keep hassan as a guide and driver during their entire stay. the dragoman's services were not expensive, and besides, both of them felt they had found a friend. the way hassan had pitched in at the bazaar, with no questions asked and their interests obviously at heart, had been a fine example of professional loyalty coupled with a quick mind and fast reflexes. after breakfast the boys went to the wardrobe and took out the coats they had brought. rick's was brand new, a christmas present from his father. it was a short, hip-length woolen coat that could double as a hunting jacket. in addition to the big outer pockets, it had inner game pockets lined with a leatherlike plastic. it was warm, but light. he was thoroughly pleased with it. scotty slipped into his own short coat, much like rick's except for the game pockets. then the ex-marine motioned to the egyptian cat, unwrapped and sitting in elegant repose on the writing desk. "what about felix?" he asked. rick went over and picked up the cat. "we'd better take it along, i guess. it might get lonesome. or we might run over ali moustafa on the way to the project." he slid the cat into an inner pocket. it fit with room to spare. scotty asked hassan, with mock seriousness, "you know sahara wells?" hassan answered with equal seriousness. "know sahara wells well." the ride was an interesting one, up the nile to a bridge different from the one they had crossed en route from the airport, along roads with a palm-shaded center strip, past mosques, stores, and airy, modern apartment houses. there was less traffic than in downtown cairo, and hassan went faster. scotty muttered, "fewer close calls today." rick winced as the car almost scraped a woman with a basket of fruit balanced on her head. "fewer, but closer." the costumes on the street were mixed. there were many people, including women, in western dress, but there were also many women in cloaks, and men in the traditional arab _bornoss_, the enveloping robe called a burnoose in english. for the first time, the boys saw several men in blue gowns, and rick asked hassan what they were. "_fellahin_," hassan replied. "how you say? farmers. from country. man tell me that is where your word 'fella' come from." rick looked with new interest. he had heard of the _fellahin_, the farmer-peasants of egypt. many of them lived and worked as their ancestors had centuries ago, plowing with wooden plows, living in mud-and-wattle houses. they represented the past of egypt, as installations like the atomic energy plant at en-shass, or inchass as it was sometimes called, represented the future. there were soldiers along the route, too, dressed in british-style brown uniforms. some carried sten guns, vicious little submachine guns originally of english manufacture. "why the soldiers?" scotty asked. "camp near," hassan replied. and then, abruptly, the boys lost interest in people, because looming ahead, like something from a travel movie, was a pyramid! hassan rounded a corner and another pyramid came into view. they were enormous, rick thought. he hadn't expected anything so huge. "are we at giza already?" he asked. "this giza," hassan agreed. he pronounced it more like _gize'h_. "i always thought the pyramids were out in the desert," scotty objected. "is true," hassan said. "you will see." they did, within minutes. the terrain changed from the green, fertile, nile valley to the bleak sahara as though cut by a giant knife. for the first time, rick understood the phrase "egypt, gift of the nile." where the yearly nile overflow brought fertile silt and moisture, there was lush green land. where the overflow stopped, the desert began. no intermediate ground lay between. egypt consisted of the nile valley and the desert, with nothing in between. the road crossed the dividing line and they were in the sahara desert. hassan drove between houses of faded red clay and tan stucco, unlike the modern apartments a few hundred yards back. it was as though they had driven into a different country. children, goats, chickens, and arab adults scattered before the car. it was a typical desert-country scene, and right at the edge of modern cairo! hassan turned a sharp corner and giza lay before them, up a gradual, rising slope. in the immediate foreground was the sphinx. rick's first impression was that it was disappointingly small, as the great pyramids behind it were truly enormous. he could see all three giza pyramids now. then he realized that his impressions had been gained entirely from pictures--and to an extent, the pictures had been false. the sphinx, always shown in the foreground of pictures or taken from a low angle, loomed large in the camera lenses, with the pyramids looking relatively small in the distant background. human vision set the image straight, abruptly. the sphinx was small, but only in comparison to the pyramids. actually, it was a monument of heroic proportions. "please stop," rick called, and hassan did, with skidding wheels. the boys got out and stood gazing, in mixed awe and delight. this was the egypt of antiquity, rick thought. these were the monuments of a civilization already ancient when the old testament was new, monuments engineered with astounding precision when rick's anglo-saxon forebears were still building crude shelters of mud and reeds. scotty's nudge aroused rick from his reverie, and he turned for a close-up of his first live camel, not counting circuses or zoos. the camel was such a vision of homely awkwardness that rick had to laugh. the cameleer led the beast to where a party of tourists, obviously american, waited. the boys watched as the animal came to a halt. the driver bowed to the party. then, taking a thin stick, he tapped the camel on bony knees that were wrapped in worn burlap. instantly the camel let out a heartrending groan. its ungainly legs folded like a poorly designed beach chair, and moaning in pure anguish, it knelt. a lady tourist, giggling self-consciously, climbed up on the blanket-covered saddle. the camel let out a louder groan, one filled with such phony pain and despair that the boys burst out laughing. a tap of the driver's stick and the camel lurched to its feet, hind legs first like a cow. the lady tourist squealed mightily, the camel wailed in protest, the other tourists cheered, and the boys doubled with laughter. rick asked, still chuckling, "hassan, do camels always complain like that?" "is true. they nasty and plenty noisy. they hate work. driver makes them carry tourists and they holler plenty." the camel quieted down to a low-voiced grumble. he was letting the world know that the arrangement was not pleasing and that he didn't intend to suffer in silence. cameras began to snap, recording for the folks back home the undignified ride of the lady tourist on the ungainly camel before the ancient, majestic pyramids and the changeless, unsmiling sphinx. the three got back into the little car and hassan took a road that curved gradually around a hill, past a hotel that he identified as the mena house, and up to the largest pyramid, once the tomb of khufu and still the greatest monument in all the world. on a line into the desert were the slightly smaller pyramids of kefren and mankara. these, with the sphinx, were among the seven wonders of the ancient world. later, rick promised scotty, they would explore giza and its wonders inch by inch. but now they were due at sahara wells. hassan sped around the khufu pyramid and pointed. there, on the horizon, was a strange contrast to the monuments of the pharaohs. the steel-and-aluminum shape of the great, steerable dish antenna, designed for modern astronomy, was silhouetted against the sky. rick was excited. he enjoyed new sights and experiences more than most people, and here, within sight of each other, were unique objects of almost equal interest, but entirely different. the way led past a single large building surrounded by shabby tents, and a sign in english and arabic that proclaimed that this was sahara wells. then the blacktop road curved out into the desert to the great radio telescope. hassan drove into a parking lot before the main project building in the shadow of the antenna and dr. hakim farid came out to greet the boys. "welcome to sahara wells," he said cordially. "how do you like our baby?" rick looked up at the huge dish. "it's a good mate for the pyramids," he said. "pretty impressive," scotty added. "we hope its performance will be impressive, too, once we get this bug ironed out. come on in. winston and kerama are hard at work." the boys followed him into the building, while hassan squatted in the sun next to his car. the door opened directly into the main control room, a bewildering confusion of panels, instruments, and controls. there were several scientists and technicians clustered around winston and kerama. the group was studying sanborn tracings, continuous graphs showing the lines traced by the incoming signals. farid introduced the boys to the staff, then took them on a quick tour. he showed them the controls for the great dish. they were fully automatic. the operator needed only to set the co-ordinates for the part of the sky to be examined, then clock mechanisms of remarkable precision would keep the telescope on target until the target sank below the horizon. the boys examined banks of amplifiers that would turn faint signals into usable ones. the latest techniques had been used to ensure maximum performance. outside, farid showed them the self-contained diesel-electric power plant. they stood directly under the massive concrete mount for the great dish and marveled at its size. the main bearings on which it moved were bigger around than scotty was tall, yet the whole affair was so delicately balanced that a tiny electric motor could control it with fantastic precision. still under construction were offices and barracks. the latter would allow the scientists to stay there for days at a time when working on particular projects. the offices were nearly done, and plasterers were at work, but the forms for the barracks floor were just being completed. the pouring of concrete would start on the following day. rick looked at the pyramids on the horizon and contrasted this scene of construction with the one that had produced the great tombs. then, it was only men--thousands of them. today, it was a handful of skilled workers plus machinery. "now," farid said, "let's get back to the control room. kerama is going to review the situation for the staff. some of them are new on the job." as farid and the boys rejoined the others, dr. kerama was pointing to a series of peaks on the sanborn tracings. "you will note that these peaks occur at intervals, with the spacing apparently random. the main sequence of noise out of which the peaks rise is the 21-centimeter hydrogen line. notice also that the peaks have nearly identical amplitudes. obviously, the source is neutral hydrogen, which is to say hydrogen in its normal form, not ionized as we find it in plasma in a star's atmosphere. our problem is simply to locate the source of the peaks. somewhere in the circuit there seems to be an effect that serves to modulate the incoming signal. our antenna will be useless unless we eliminate this interference so that the signal can be pure once again." rick had seen sanborn tracings before. the system was a standard method of recording. his first experience with it had been in making permanent records of telemetered signals from rockets. a technician asked, "sir, do these peaks occur no matter how the antenna is pointing?" kerama shook his head. "no. if you will examine the peaks in terms of time and the co-ordinates, you will see that they began at a particular point during a sweep of the sky. our first thought was that we had picked up some source emitting pulsed signals, but the source is apparently moving. this is why we concluded the difficulty was in our system, since no sky source moves with such angular velocity." the egyptian scientist began giving assignments. rick and scotty were given a test kit and put to work checking a part of the circuit one wire at a time. it was slow, difficult work, requiring great care. it was warm in the control room. rick hung up his coat, pausing to touch the egyptian cat in his pocket. he hadn't thought of the little beast for some time. what was he to do with it? from a simple delivery job, as a favor to an acquaintance, the cat had become a problem. rick couldn't resist a mystery, but this one had him stopped cold for the time being. he didn't know what to do next. the only solution that had occurred to him was to send a cable to bartouki, to ask for further instructions. he shrugged and put the problem aside, and went back to helping scotty. it was late before kerama called a halt. the boys rode back to the hotel with hassan, grateful for the relief of concentrating on thousands of tiny wires. they told the dragoman to go on home, then went into the dining room for dinner before retiring for the night. winston, who never seemed to tire when working, had stayed with kerama and farid to continue discussions of possible sources of trouble. after dinner rick picked up their key at the hotel desk and they rode the tiny elevator to their floor. they opened up and went in. rick locked the door while scotty snapped on the lights. scotty let out a sudden yell! rick whirled and gasped. the room was a shambles. every drawer was open and their contents were dumped out on the floor. their suitcases had been left open. the bed-clothes were in a heap in the middle of the room, and the mattresses were on the floor. rick glanced at the key in his hand and realized that it was a very ordinary type; master keys that would allow a thief access could be bought in any hardware store. he followed scotty to the closet and saw that their clothes had been searched and dropped carelessly. nothing was left on the hangers. the room had been searched inch by inch, and by someone in a hurry. rick's hand went to the egyptian cat in his pocket. "they wanted the cat," he said slowly. "i can't see that anything is missing. but why is the cat so important?" he drew it out of his pocket and stared at it. then his eyes met scotty's. his pal shrugged. neither of them had even the slightest clue. chapter vi the cat has kittens the sun blazed down on sahara wells. in the distance the pyramids looked hazy, and beyond them cairo was a thin line of green and brown along the nile. it was fairly warm in the sun, but a cool wind blew across the desert and coats were comfortable. rick and scotty sat on a box under the antenna while hassan squatted and watched them. for the moment there was nothing for them to do. the scientists were occupied with calculations, and neither boy could make a contribution to high mathematics of the kind used in radio astronomy. rick was glad of the break. his mind hadn't been on the job, anyway--it had been on the egyptian cat. for perhaps the hundredth time he asked, "why is the cat valuable? why would anyone want it enough to stage that scene at el mouski and then ransack our room?" scotty had no answers, but he had some questions of his own. "what i want to know is, did the hall porter just happen to step out at the right moment for the thief? or is he in the act somehow?" "it really doesn't make much difference," rick pointed out. "he might have been paid to take a walk, but that doesn't mean he knows anything." "okay. try this one. where is the real ali moustafa?" "good question. now i'll ask one. what do we do next?" "you could cable bartouki, or even phone him," scotty replied. "you said you had thought about it." rick hesitated. he tried to put his reluctance into words. "i just don't think getting in touch with bartouki is the right thing to do. i don't know why. call it a hunch." scotty had a deep respect for rick's hunches. they had a way of turning out to be right. he remembered a description of a hunch rick had once used and repeated it. "a hunch is only a conscious conclusion based on subconscious data you don't know you have. isn't that about it?" rick looked at him. "what are you driving at?" "what data are buried in your subconscious that make you distrust bartouki?" "i didn't say i mistrusted him." scotty shrugged. "no, but you must, if you don't think it's right to call him." rick had to admit scotty was probably right. what basis did he have for mistrusting the charming little egyptian merchant? certainly bartouki had been nice to them, so carrying the cat to egypt had been only common courtesy. experience had shown rick that very often he could get ideas from reviewing conversations. he walked away from hassan and scotty and stared at the construction details of the antenna. but he wasn't really looking. instead, he was trying to recall the entire scene leading up to his acceptance of the cat. bartouki had explained its importance. he had said it was needed. now, what had led barby to offer rick's services as a messenger? the merchant had said that he was anxious to get it to egypt, but that the christmas mails were crowded. the christmas mails ... that didn't seem like much of a reason for not sending it by air freight. bartouki could have delivered it personally to idlewild terminal, to avoid getting it mixed up with the domestic mail.... "i've got it!" he yelled. he hurried over and stood in front of scotty and hassan. "listen, who sends mail at christmas time?" scotty's brows wrinkled. "everyone, i guess." "not everyone." rick warmed to his idea. "there are plenty of people who wait until the last few days before christmas, but where are they? in america! anyone overseas who sends a package home tries to get it in the mail early. wouldn't you say so?" "maybe they should, but i suspect they don't. people are always waiting until the last moment." "but is the overseas airmail so crowded you wouldn't trust a parcel to the regular mail system?" scotty shook his head. "i doubt it. what are you getting at?" but rick had an even better argument to bolster the case he was developing. "christmas mail is to and from christians, isn't it? sure! egypt is a moslem country. moslems don't send christmas cards or presents, and they don't get them, either. the christians in egypt are coptic--anyway, they don't celebrate christmas the same way. so why would the airmail to egypt be jammed?" hassan spoke up. "it not so heavy. my brother is letter carrier, and he no work very hard on _nasrani_ holiday. nasrani is what we call christian." "i think you've got something," scotty agreed. "bartouki could have mailed the cat, but for some reason he wanted a messenger ..." "... and we walked right into it," rick finished. "chances are that's why he showed us the cat in the first place." "barby had the bright idea," scotty reminded. "bartouki wasn't the one who suggested it." "he didn't have to," rick pointed out. "if she hadn't, i'll bet he would have led around to it some other way." scotty held up his hands in surrender. "i'll buy it. bartouki needed a messenger. why?" rick sat down on the box again. why, indeed? he knew now why he distrusted bartouki, but he had no idea of the merchant's reasons. he glared at his pal. "kill-joy. so we get back to the basic question. what does kitty have that people want?" he took the statue from his pocket and examined it closely, as he had done several times before. the bright sunlight disclosed nothing but a perfect bit of casting. he took out the pocket lens he carried for examination of specimens that might be useful in his hobby of microscopy, but magnification showed him nothing. it was a flawless job. "i'm stumped," he admitted. "come on. let's stretch our legs before we get called back in to go to work." scotty and hassan joined him as he walked toward the barracks where cement was being poured to form the floor. scotty borrowed the cat for a quick look, then handed it back. rick stowed it in his pocket. "whatever kitty's got, it's pretty interesting to some people," scotty commented. "otherwise, why go to all the trouble of trying to get it in the bazaar, then taking the risk of searching our room?" rick said what had been on his mind. "i have another happy thought for you. if they really want the cat, they'll try again." "whoever 'they' are," scotty agreed. "let me add a cheery note of my own while we're at it. they won't have to get the best detectives in the world to figure out that you've got the creature, either. if it isn't in the hotel room, it's on you." rick mulled that one over as they watched the workmen smoothing the poured concrete in the form. would it be better if he disposed of the cat? but how could he? he couldn't leave it at the project, even though it was locked at night. the lock wouldn't stop professional thieves. he couldn't give the cat to one of the scientists, because that would expose them to the thieves, too. he could have it put in the hotel vault, but what assurance had he that it would be safe there? it occurred to him that he would have entrusted his valuables to the hotel vault with no hesitation, but the cat was different, somehow. he just didn't want it out of his hands until he knew more about it. hassan said idly, "cement color like cat." rick's thoughts snapped back to the scene before him. the dragoman was right. the concrete mix had been colored to imitate sandstone, apparently a part of the plan to make the architecture as egyptian as possible. there was enough of the mix in the form to make a thousand cats, and more was being mixed in a portable cement mixer. the great idea took shape in his mind, and suddenly he laughed outright. "kittens!" he exclaimed. "wouldn't that throw them for a loop? i mean, if several egyptian cats showed up." scotty laughed with him. "it definitely would. we'll show 'em that it doesn't pay to confuse us. only how do we do it?" rick pointed to the office building where the plasterers were still at work. "make a plaster cast, then use the concrete mix for the models. how about it?" "could work," scotty said quickly. "come on." they rummaged around through the construction debris and found a pair of small wooden boxes that had held instruments. with hassan as interpreter, rick talked to the construction foreman and a plasterer was detailed to help. if the form could be prepared right away, the low desert humidity would harden it enough to use by the time they were through work. the wooden boxes were filled with soft plaster while rick coated the egyptian cat with oil used to lubricate the antenna bearings. the cat was pushed into one box until only half of it showed. the plasterer smoothed the surface around the cat. a sheet of scrap metal was used as a lid for the second box of plaster. working quickly, the plasterer turned it upside down and held it in position while scotty slipped the metal out of the way. the plasterer pushed it down on the cat, losing only a little plaster in the process. the little statue was now firmly embedded in plaster. by the time the boys were summoned to the control room again, the plaster was firm enough so the plasterer could run a thin wire between the two boxes to start the process of separation. when the plaster was a little harder, he would use the wire and a long knife to separate the two halves completely. the boys went to work, checking various elements under winston's direction. they kept at it until late afternoon. the sun was slanting down behind the pyramids when they were told to knock off for the day. they hurried to the plaster mold at once. hassan was already there, waiting, with the plasterer. the sudanese guide pointed to a batch of concrete in a wooden tub. "we mix, more dry than for the floor, so easier to make cats. now we start?" "any time," rick said. "thanks, hassan." the resourceful dragoman had realized the concrete mix being used for the floor was too liquid for easy handling and had prepared a drier batch. the plasterer went to work at once. he worked rapidly but skillfully, using the wire and knife to cut through the plaster until he reached the cat. rick worried that he might cut or scratch the original, but the egyptian was deft. in a few moments he lifted the upper box and the cat came to light, still gleaming from its coating of oil. rick lifted it out of its plaster bed. the two boxes now contained perfect half impressions. the boys, hassan, and the workman shook hands all around. it was a job well done. the rest was easy. rick oiled the form while the plasterer put the new concrete mix through a screen to remove lumps, then the two halves were filled slightly overfull and put together. pressure was applied simply by standing on the upper box. the workman lifted the upper box off with great care, disclosing a perfect half-cat in fresh concrete. the dry mixture kept its shape, but made great care necessary. the egyptian workman held out both hands and hassan turned the bottom box over. working gently, the plasterer released the casting from the mold. it dropped into his hands. the boys watched eagerly as he used his knife to trim the flashing from the cat replica, then he wet his fingers from a bucket and smoothed out a few rough spots. the man grinned with pleasure, and the boys grinned back. "perfect," scotty said. rick added, "if i didn't know its mother personally, i'd think this was it." the first kitten was put gently aside to dry while others were cast. the next two castings broke, but three perfect kittens resulted from six tries. rick was satisfied. "by tomorrow they'll be hard," he said with a grin. "then we'll work out a cat distribution program. i may go back to el mouski and hand one to the phony ali moustafa, just to see what happens." "not while i'm healthy enough to stop you," scotty said positively. then he grinned, too. "but there's nothing more fun than kittens, and we'll have plenty of laughs with these. you wait and see!" chapter vii the egyptian museum rick hung up the room phone and joined scotty at the breakfast table. the ex-marine was munching on a lebanese tangerine and watching the nile boats below. "farid says to take the morning off," rick reported. "the scientists are about convinced that the signal isn't internal receiver noise, but that leaves them up a tree. if part of the circuit isn't causing the trouble, what is?" scotty waved his hand at the scene across the nile where a great concrete tower rose into the sky. "it's this land. look at it. there's a tower for television. a couple of miles away are the pyramids. down the street is a new office building with aluminum walls, and it's right next to a stone mosque that's nearly as old as the city. if you ask me, horus or thoth or one of the old egyptian gods is getting fed up and messing with the signal just for the fun of it." rick knew exactly how scotty felt. the remarkable blend of the very old and the ultramodern was visible everywhere in cairo. but somehow the two did not conflict, probably because the egyptians had been wise in their choice of architecture. "maybe we'd better burn some incense and do a chant or two," rick suggested. "how's this? oh, osiris, son of isis, please get the bugs out of our antenna." "that's no fit chant," scotty objected. "a chant should rhyme, shouldn't it?" rick searched his memory for incantations to egyptian gods, but there had been none in the books bartouki had given them, although the gods had been described. he improvised quickly. "then how's this?" he took a pinch of sugar from the bowl and sprinkled it on scotty's head as an offering to the gods, then bowed like a high priest and chanted: "_anubis, horus, amon-rã©, are you near or far away? if you're tuned in close at hand, clean up the h-emission band._" the piece of hard egyptian bread thrown by scotty caught him just behind the ear. rick picked it up and threw it back, grinning. "the things i have to put up with," scotty exclaimed hopelessly. "i'm sorry i brought the whole thing up." "it didn't help," rick admitted. "but it gave me an idea. how about going to the egyptian museum this morning?" "with hassan?" "it's right across the park. hassan can take the morning off and come back after lunch to drive us to the project." "i'm your boy," scotty agreed. "if you keep your chants to yourself, that is. try one on those old statues at the museum and they'd fall on you." "oh, i don't know," rick said loftily. "maybe those old egyptians had a better ear for poetry than you have." "that's what i'm afraid of," scotty returned. "if it sounds so terrible to me, think what it would sound like to a poetry lover. go on and make your phone call." rick did. he asked the desk to relay a message to hassan, then asked about the weather. the clerk spent a minute apologizing profusely. it was chilly, he admitted reluctantly. very unusual for egypt. hadn't happened since 1898. most regrettable. and so on. "he sounded like a sunshine tourist service trouble shooter explaining that the downpour was only a heavy mist," rick said as he hung up. "the weather is unusual, remarkable, etc. it's chilly." scotty finished his coffee. "okay. let's go. got the kitty?" rick took the egyptian cat from its nest under his mattress and put it into the inner pocket of his coat. "couldn't leave our pal, could we? bad man might get 'im." "we can't let that happen until we find out why the animal is so appealing," scotty agreed. "spoken like a true spindrifter. do we walk, or take the elevator? walking's faster, but the elevator is more adventurous." "walk," scotty said. "you need the exercise." outside, the air was pleasantly crisp, but the sun was shining. rick wondered if it ever rained in cairo and made a mental note to look it up. he had brought a guidebook with him, and the map showed them the location of the museum. they started off at a brisk pace, past the nile hilton hotel, then across the heavy traffic of the bridge circle to the open park before the museum. as rick turned to look at a statue he caught a glimpse of a figure dodging behind some shrubbery. his pulse speeded. "could be that we have a buddy," he announced. "i saw someone dodge behind a bush." scotty took a quick look without seeming to. "someone there all right. a pal of our little cat?" "it's certainly no chum of ours, if it's anyone who's interested in us. let's hike and see how it goes." they strolled idly past the museum, crossed the street, and walked up kasr el nil past the modern art museum and the automobile club. scotty took a pair of sunglasses from his pocket. they were of the silvered one-way mirror type that cuts down light transmission much as a neutral-density filter does for a camera. rick watched as he put them on, took them off again, and polished them with a handkerchief, turning them from side to side as he watched for spots. "i knew those things looked like headlights," rick gibed. "i didn't know they could also serve as rearview mirrors." "i may write an article on this for the journal of the optical society," scotty said. "works fine. our buddy is a sudanese, from the looks of him. also, he has a comrade. a big, sloppy type in a black coat and a tarboosh. i'd hate to tangle with either of them." rick thought of scotty's comment that it wouldn't take much of a detective to realize he had the cat on him. scotty added, "some distance behind are two other types, in tarbooshes. they're striding along at the same pace we are, and keeping their distance. i'm flattered. looks as if 'they' figured it would take four to handle us." "maybe they sent one for us and three for the cat," rick said hopefully. "cats are good scrappers. any bright ideas, ol' chum?" "yep. let's go to the museum. they can't touch us in a public place. got the map?" they consulted it, letting the trailers see what was going on. the street they were on formed one side of a triangle, with its apex at the square in front of the museum. the next left turn, and another left a block farther on, would bring them to the front of the museum through gami sharkas and shampelion streets. rick wondered if the latter was the arab-english equivalent of the name of the man who had translated the hieroglyphics on the famous rosetta stone and is considered the father of egyptology. he knew from his study of cryptography that the first man to read the strange egyptian written language was jean franã§ois champollion. or maybe the map maker had made a mistake by misspelling the name. he looked for a street sign in english when they reached the street, but he saw none. he had to grin to himself at the strange turns his mind sometimes took. he should be concentrating on a plan of escape, not wondering about a strange spelling of a frenchman's name. "see anything?" he asked scotty. "they're still with us. all four." "probably the second pair is in case the first pair loses us," rick guessed. "let's keep out of deserted alleys. they must be just waiting for an opportunity to grab us." "i hear you talking," scotty agreed. "and i believe every brantish word of it." they turned into the museum grounds, waving off guides who came running. normally, they might have hired a museum guide, but they were suspicious now of all strangers. rick produced some piastres and paid their entrance fee. he noticed a sign at the window that said all parcels must be checked. he was glad kitty was hidden in his pocket. inside, they paused at the sudden spectacle of great stone figures and huge stone sarcophagi. there was a great hall filled with giant statuary straight ahead, and on each side, wide staircases led to the upper floor. "topside," scotty said. "then we can look down and see if any familiar faces come through the door." they walked up the left-hand staircase, past rows of ancient wooden mummy cases, and came to the upper landing. a few minutes were spent inspecting the last resting place of a one-time egyptian lord, with frequent glances toward the entrance. "they don't need to follow us in," rick pointed out finally. "sooner or later we'll have to go out, and they'll be waiting." "sure. but it's wise to be careful. if one had followed us in here, we'd have been forced to keep an eye on him. me, i want to see this museum." they wandered through the countless rooms of the upper floor, each filled with antique treasures that were impossible to identify. there were few cards of explanation. one room was crowded with alabaster carvings, any one of which would have rated a whole room to itself in a modern american museum. the great building was literally jammed with rare objects, many of them thousands of years old. uniformed guards were posted at every corner, obviously to protect the myriad treasures. "the police are keeping an eye on us," rick muttered. "what else are they here for?" scotty commented. "don't try to carry off one of those ten-ton statues and they won't bother you." rick paused before a collection of brightly painted miniature clay soldiers, created to serve as a phantom army for some forgotten nobleman. "this stuff is priceless. i'll bet they really do need guards." as the boys walked into a small room containing shelves of assorted clay and stone dishes and utensils, scotty exclaimed, "look, on the third shelf!" rick searched until he saw what scotty's quick eyes had spotted. it was partly hidden behind a clay jug. an egyptian cat! closer inspection showed that it was not the mate to the one he carried. the museum cat was darker, obviously older. it was more stylized and slightly larger. there was no identifying card. the egyptian cat returned his gaze with dark stone eyes. "wonder if they'd like to have you, too?" rick said to himself. four men wanted the one in his pocket. he wished it was as safe as the antique before him. suddenly he let out a pleased chuckle. he had the solution. "are you lonely, little cat?" he asked. "would you like company?" scotty got it instantly. he patted rick on the shoulder. "that's the old brant brain, boy. i'll duck out and distract the guard." rick moved on, inspecting jugs until he saw scotty engage the guard in conversation. his pal gradually turned as he talked, until the guard's back was toward rick. it was the work of only a moment to slip the cat from his pocket and push it out of sight behind the jug that partially screened the museum cat. he smiled to himself. from the looks of the museum, it was highly unlikely that the cat ever would be noticed, even if it stood there forever. if one of the egyptologists ever did happen to see it, there would be a new puzzle to solve. which dynasty invented plastics? [illustration] he walked to where scotty was busy with the guard. the officer's understanding of english was about zero, and scotty's knowledge of arabic was slightly less, so they were getting nowhere. when he saw rick, scotty stopped trying. he grinned and put out his hand. the guard grinned back and clasped scotty's hand, with obvious relief that the struggle to communicate was over. he waved cordially as the boys went on their way. "it is a distinct privilege to make such an outstanding contribution to egyptian culture," rick said. he was really relieved. being unfamiliar with cairo, they were apt to walk into an unexpected situation that might have resulted in loss of the cat. there would be no reason for anyone to suspect the cat's hiding place now, because no one except scotty knew that he had carried it out of the hotel. there was much to see, and the boys took their time, spending over an hour in the section devoted to the relics of tut-ankh-amon, the boy pharaoh who had died at about the age of eighteen. his tomb had been found intact, one of the few that had escaped the desert thieves. priceless objects had been found, including the king's death mask of painted gold. it was one of the most beautiful objects of art the boys had ever seen. rick noted that at least one guard was always within easy reach of them, and that several guards patrolled the area. the area itself could be fenced off by steel grillwork. he agreed thoroughly with the precautions. the sheer weight of gold would be worth a pharaoh's ransom, even if melted down. in their present form, tut's treasures were beyond price. the pangs of hunger finally drove them from the fascinating place, and both agreed to return with someone who could explain what they were seeing. they emerged into the brilliant egyptian sunlight and stood blinking. "we'd better head for the hotel on a beeline," scotty suggested. "no sense in taking a chance on getting roughed up for nothing." "that's sense, ol' buddy. let's go." they walked down the steps and out a path to the street. an old man with a pushcart was on the path, his cart laden with nuts of some kind. rick stepped behind scotty to give the vendor room, but the old man turned his cart suddenly and pushed it into them! the cart upset and nuts cascaded underfoot. the boys struggled for balance. "watch it!" scotty yelled. four men bore down on them at top speed, screaming imprecations in arabic. rick saw the setup instantly. the four would simply be retaliating for the treatment of an old man by two foreigners. he got to his feet just as the four arrived, and saw that scotty was crouched beside him. the sudanese and the big man in the tarboosh dove for the boys like a well-rehearsed wrestling team! chapter viii the midnight call rick and scotty left the ground simultaneously in a dive for the legs charging toward them. they connected, and the impact sent the attackers to the ground. rick recovered from the dive and tensed for a swing, but he never made it. arms locked around his chest, pinioning his own arms to his side. he struggled violently, but the grip never yielded. from the corner of his eye he saw scotty get in one driving punch that sent the sudanese down to one knee, then scotty was pinioned from behind, too. the big man and the sudanese swung into action fast. hands slapped rick's clothes in a fast but thorough search. next to him scotty was getting the same treatment. the big man spoke sharply in arabic and both boys were suddenly hurled sideways, landing together in a heap. they jumped to their feet and saw only four retreating backs. even the peddler had scuttled away, leaving the spilled nuts on the ground. it was senseless to pursue the men. the boys looked at each other grimly, then suddenly scotty smiled. "i don't know who they are," he stated, "but i'll tell you this. they're real professionals. i haven't been taken like that in a long, long time." rick had to agree. the two-team operation had been swift and efficient. neither boy had been hurt, or even roughed up particularly. that wasn't the purpose. "so they won't get us in a public place, huh? well, if they'd wanted to do damage, they could have." he added, "and we couldn't have done a thing. but all they wanted was the cat." scotty nodded agreement. he brushed dust off his trousers. "might as well go back to the hotel. i'm hungry. anyway, they know now that you don't have the cat on you--and that i don't, either. so what will they think?" "either that it's at the hotel or the project, or that we've put it somewhere for safekeeping. they searched the hotel room. suppose they'll try the project?" "it's possible, i suppose. anyway, if they want us they can get us. notice that no one saw the ruckus? the timing was perfect. a few feet sooner and we'd have been within sight of the museum's ticket office. a few feet later and we'd have been on the street. as it was, shrubs shielded them. pretty good operating, i'd say." rick thought so, too, and it worried him. "i have an unhappy idea buzzing around. if i were the big boss, and really determined to get the cat, i'd pick us up and make us talk." "the language is a little mixed, but the thought is clear as air. we'd better keep our guard up at all times." "meanwhile, what do we know about anything? nothing. if only we knew why the cat is valuable!" "if it wasn't before, it is now," scotty replied. "it's a genuine museum piece. but if the cat is gone, we have three lovely kittens." rick chuckled. "what's the problem everyone has with kittens? it's finding a home for them. i wish we'd had one of the kittens a few minutes ago. there would have been one less homeless orphan." "the kittens' turns will come. and it's our turn to eat. my stomach is quivering in morse code. 'send food. send food.'" rick pointed to the hotel, just ahead. "okay, chow hound. lunch ahead. and lay off that hot-pepper stuff or that stomach of yours will be sending distress signals." "i hear you talking," scotty said feelingly. one dish, served at dinner the previous night, had required enough water to put out a three-alarm fire before the burning sensation stopped. hassan was waiting after lunch. he drove the boys to the project, where they looked into the control room long enough to let the scientists know they had arrived, then went at once to look at the kittens. three identical statues, almost perfect replicas of the original, were sitting in the sunshine. "except for being a little rougher, they're our own dear little mysterious pet," rick said. "are they dry yet?" hassan passed the question on in arabic to the workmen who had helped make the kittens. he reported, "they okay. you can take now." "ask him if we can give him a present for helping us," scotty requested. hassan did so, then shook his head. he grinned, his teeth white in his pleasant black face. "he say making statues fun, not work. he help you yesterday, so he not have to fix plaster. all even." the boys laughed at the explanation and shook hands with the workman. "now," scotty asked, "what do we do with the children?" "one goes in my pocket," rick replied. "i feel lost without a friendly little feline weighing down one side of my coat. we can leave the others here in a safe place, maybe inside one of the control cabinets." "good idea. going to tell winston and the others about this morning?" "sure. only i don't think we'll mention where the mama cat is hiding out. no use bogging them down with useless information. we'll tell winston." scotty quirked an eyebrow. "not suspicious of the others?" rick wasn't, and said so flatly. "only the more people who know something, the more others are apt to find it out." the scientists, however, were not even remotely interested. their whole attention was given to the problem of getting the big radio telescope working. hakim farid joined the boys long enough to say, "we've about decided the strange signals are not originating within the system. now we're looking at the possibility that some local source is giving us interference. we thought we'd eliminated all outside noise, but perhaps something new came up after we finished checking." rick pointed to cairo, visible through the control-room window. "there must be lots of stuff down there that puts out radio-frequency signals, even electric shavers and heating pads. how can you eliminate all of it?" "we can't, in the sense of really cutting it out. but the antenna construction takes local interference into account. it's a tight beam design that should prevent overriding of the main signal by any random side effects. that's what kerama and winston are checking now. there's not a great deal for you to do until they're through. in a half hour we'll start to swing the antenna to see if we get an increase in the signal by a change in direction. until then, why not take it easy?" "we will." rick took the opportunity to tell farid of the incident at the museum that morning. he described briefly how they had been followed, then attacked on the museum path. farid frowned. "i'm sorry to hear it. cairo is pretty law-abiding, compared to what it used to be. but we still have crime, just as you do in your big cities. you didn't lose your wallets or anything valuable?" "nothing. we think they were after the cat." "they didn't get it?" "no. i didn't have it on me." "that was fortunate." farid frowned. "but why would anyone want the cat?" rick did not have an answer for that, and said so. the scientist smiled. "a cat isn't exactly big game for thieves, is it? on the other hand, the museum itself was robbed several weeks ago in spite of the guards. thieves got away with a necklace supposed to have belonged to kefren, who built the middle pyramid over there." "was it valuable?" scotty asked. "more than valuable. it is irreplaceable. in terms of cash, however, the value is around a quarter of a million dollars." rick whistled. "no wonder the guards watched us this morning." dr. kerama called, "hakim, can you help with these tracings, please?" farid joined the other scientists, leaving the boys to their own devices. rick hunted until he found a space under an amplifier that was big enough for the two extra kittens. the space was covered by an access door. the kittens would be safe there. it would be no real loss if they were stolen, anyway. later, the boys helped check circuits while the radio telescope swung through a variety of arcs, with farid at the controls. the strange signal came while the telescope was pointing only in one direction. rick asked winston, "could it really be coming from a single source in outer space?" winston shrugged. "we've thought of that. if the source remained fixed, we'd accept it as the most logical explanation. but since kerama and farid first noticed the signal it has shifted its apparent location by many degrees. that's why we think it must have some local explanation." rick understood. the sources in space studied by the radio telescopes were fixed, in the same sense that the stars themselves were fixed. of course everything in the galaxy--even in the universe--was in motion, but in spite of the enormous velocities, the change in location would not be particularly apparent in a short time, or even in a lifetime. a short distance away was a wonderful example of this kind of motion. in the great pyramid of khufu, rick had read, a channel had been left so the light of the north star could shine on the altar of isis. the channel was still there. but in over three thousand years the slight, slow wobbling of the earth on its axis had caused a shift. what was then the north star was now thuban, in the constellation of draco the dragon. the present north star, polaris, which is not exactly at the celestial north pole, did not shine on the altar. nor would the next star to become the northern marker--bright vega. but if the pyramids were still standing after twenty-seven thousand years had passed, the cycle of movement would be complete, and thuban would again shine through the channel to the altar of a forgotten egyptian goddess. it gave rick a shiver to think about it. even now, the pyramids were old enough to have seen a change of north stars. they looked good for another three thousand years or more. it would take a lot of time to erode away that much massive stone. then he stopped thinking about it, because the telescope was in motion again, and there was work to be done. it was late night before the scientists were satisfied. the boys rode back with hassan, very thoughtful about the day's events. now they had both the little statue and the even greater mystery of the space signals to think about. clearly, the strange signal was not of local origin. the scientists rejected the idea that it came from trouble in the circuit. but it was no natural heavenly object. what was it? tomorrow, winston had said, they would decide on the next step. right now all hands were too tired to think clearly. the boys agreed that the statement applied to them. "shall we eat?" rick asked as they approached the hotel. "let's have a sandwich sent up," scotty suggested. "i don't feel like waiting in a dining room, even if one is open this late." "good idea." rick leaned forward and told hassan, "just drop us off, then go on home and get some rest." "not tired," hassan said cheerfully. "you work, i rest." they certainly were not working hassan very hard, rick agreed. but he was pleasant to have around. they bade him good night in front of the hotel and went for their room key. the clerk handed rick an envelope along with it. it was addressed to mr. r. brant, care of the hotel, and the return address was in arabic. rick waited until they were in their room to open it. a quick glance showed that the room had not been searched, or if it had, with greater care than the last time. he ripped open the envelope and took out a sheet of paper, the letterhead printed in arabic except for the name fuad moustafa. "fuad moustafa," he said aloud. "any relation to ali, i wonder?" "read it," scotty urged. rick did so. "'dear sir: you have brought to cairo, i believe, a plastic replica of a cat, which was given to you by mr. bartouki for delivery to my brother, ali. i deeply regret the inconvenience caused by your failure to find my brother in his shop. only today did i learn that his chief clerk, an officious person, had attempted to take delivery of the cat by pretending to be my brother. the clerk shall be discharged for this offensive behavior. "'since my brother is absent from the city, on business to beirut, which was the reason for his absence from the shop, i shall be delighted to serve in his stead. if you will call me, i shall come at your convenience. or, if you will do me the honor of breaking bread at my home, i shall be at your service. since my home is also my office, any time that is convenient for you will be my pleasure. sincerely, fuad moustafa.'" rick jumped for the phone and called the desk, "see if hassan is still around, please. tell him to wait, if he is." the clerk asked him to wait and rick put his hand over the mouthpiece and turned to scotty. "the first sensible suggestion we've had. let's go call on fuad moustafa. if there are lights, we'll pay him a visit. if not, we'll come back. i'm anxious to get this settled." "so am i," scotty agreed, then added, "only let's be sure this isn't a trap." the clerk came back on the line. "hassan is here. he will wait." "thank you. now, can you tell me anything about a mr. fuad moustafa? do you know him?" "indeed, sir. he is a lawyer, from a well-known family. he has two brothers who are also well known. one is ali, who has a shop in el mouski, and the other is kemel, who is a textile importer." rick thanked him and hung up. "it's our boy," he said. he repeated what the clerk had told him. "sounds like pay dirt," scotty agreed. "only we'll still be careful. let's go." rick echoed him. "let's go! if this is on the level, we can get the cat in the morning and deliver it." at last, the secret of the egyptian cat might be unraveled! chapter ix the uninvited visitor as the boys hurried through the lobby the night clerk came to meet them. "i noticed that the name of mr. moustafa was on the message i gave you. if you intend to visit him, you will have no trouble. his house is also his office, and it is very well known. just tell hassan to take you to abd el aziz street." the boys thanked him, somewhat relieved that fuad moustafa apparently was so well known. outside, hassan was waiting. "not so tired?" he greeted them. "not too tired for a short trip," rick said. "can you take us to abd el aziz street?" "not far. near el mouski." as hassan drove off, at the usual high velocity, rick asked, "do you know fuad moustafa?" "hear name," hassan said. "but not know. what number street he live?" rick took the letter from his pocket, switched on the dome light, and scanned it. there was no address given in english. he started to hand the letter to hassan, then remembered the dragoman could not read. he puzzled over the arabic in the letterhead, realizing the address must be given there. if he could identify the numbers ... there, he recognized one. both boys had spent some time studying the telephone dial at the project, on which the numbers were in arabic. it was easy to identify them, and rick had spotted the five, a figure like a tiny heart, upside down. "i think i have it," he said. "let's see. arabic reads from right to left, instead of the way we write. that makes this number ... hmmmm ... a heart, a dot, and two sevens backward with one squiggle in the upper line. the heart is a five, the dot a zero, and backward sevens with one squiggle are twos. so the number is 5022. right?" "that's the way i remember it," scotty said. "so that's the number. _enshallah._" hassan started laughing in the front seat. "now you speak arabic? you must say _a'eraf shwayet 'arabi_." "what does that mean?" scotty demanded. "it mean 'i know some arabic'" the boys laughed with him. in a few moments hassan swung the little car to the curb and pointed to the nearest building. "there 5022." rick started to get out, then he asked curiously, "how do you know, hassan? i thought you couldn't read." "no can read words. read numbers plenty good. could not take people to places if could not read numbers." that made sense, rick thought. scotty let out a sudden exclamation. "hey, this is a barbershop, and it's closed for the night." rick looked, then switched on the dome light. he compared the letterhead number and the number on the door. clearly, it was 5022, unless they had mistaken threes for twos. the only difference between the two numbers was an extra squiggle in the upper line of the three. he checked the letter again. no, they were twos. he said so. "this is the number on the letter." "you let me see, please?" hassan asked. "sure, hassan." the dragoman took the letter and examined it. he chuckled. "_samehni, ya sidi._ that mean excuse, sir. small mistake. you reading backward. number is 2205." "but how can that be?" rick asked. "arabic goes backward from english." "maybe so with words," hassan said. "but numbers not so. this number is 2205. you want to go?" rick sighed. "i learn something new every day. okay, hassan. you're the dragoman." the little car swung around and sped back the way they had come, into a better part of the city. in a short time hassan slowed and began searching. at last he pulled to the curb, in front of a large house of victorian design. "here is 2205," he announced. the boys got out and saw immediately that the house was in darkness. not a light shone anywhere. "no one home," rick said, disappointed. scotty surveyed the dark structure. "funny. a house this size must have servants. there should be a light somewhere. maybe around back?" "i doubt it, but we can take a look." hassan's voice stopped them. "something wrong, i think." "what do you mean?" rick asked quickly. hassan gestured to where a small group of people had gathered on the other side of the street. "why they stop? not so strange for car come to house like this." that was true, rick thought. the people stood quietly, watching, and in a moment two others joined them. their attitude was not simple curiosity. "can you ask them what's up?" scotty asked. "will try." hassan took a step toward the group and called cheerfully in arabic. no one answered. he walked toward them, still talking cheerfully, and the little group melted instantly into ordinary people walking the street on their various errands by ones and twos. rick needed no interpreter for their actions. rather than answer a courteous, cheerful question from hassan they had hurried off, as though afraid of something. but what? "pretty strange, i think," hassan said. "i just ask who can tell me where to find fuad moustafa, and they go." scotty had been staring at the house. he walked to the steps and stared into the darkness, then went up them onto the porch. in a moment he came down again. "something's very wrong," he said. "i thought i saw the gleam of metal, and i did. a brand-new padlock on the door! new hasp, too, put on in a way no house owner would ever do it. it's as though someone was closing a barn door and didn't care how it looked." a chill went down rick's spine. instead of a solution, they had found a deeper mystery. he was sure of only one thing for the present. they should not wait at the house of fuad moustafa. "come on," he said. "back to the hotel. if we can't have facts to feed on, we can at least have that sandwich." but the sandwich was not to be had so easily. back in their room, a call to the waiter brought the porter, who announced that all hotel facilities were closed and the waiters had gone home. he would be glad to go to a restaurant he knew of and get them sandwiches, but it would take a little time. the boys ordered, then got undressed. scotty went in to wash up while rick wrote cards to the folks at home. a knock interrupted him. "must be the porter," he called to scotty, and went to open the door. a stranger stood there, a big man in an immaculate gray linen suit. he wore thick eyeglasses with stainless-steel rims. on his curly hair was a tarboosh of red velvet. in his hand was a gleaming, snub-nosed hammerless revolver, pointed at rick's midriff. [illustration: _a snub-nosed revolver was pointed at rick's midriff_] "i know it's late," the man said pleasantly, "but may i come in?" he walked through the door, and rick backed away to make room. "are you fuad moustafa?" he asked shakily. the man smiled. "i have not that honor. you have never seen a moustafa, or you would not ask. they are famous for the biggest noses and mustaches in the republic. i could have lied, but it is my pride that i never lie. my identity is not important." "what do you want?" rick asked. he kept backing away, because he wanted desperately for the man to follow. that would give scotty a chance to move in from behind. "i think you know what i want. a small and unimportant piece of plastic, in the shape of a cat." "why is the cat so important?" rick asked. "it is not important. you may believe this. however, for reasons i shall not disclose, it has certain elements of value to a few people." "sentimental value?" rick asked. he was stalling. "it depends on what one is sentimental about. i have no sentimental attachment to this object. i merely want it. now, my time is short. i was fortunate to find the porter gone, but he will doubtless return. the cat, my young friend, and quickly!" scotty moved from the bathroom on silent, bare feet, and even as his pal moved, rick saw the object in his hand. it was a nail file. scotty stepped close and his hand moved. the stranger stiffened. "that's a knife in your back," scotty said. "drop the gun." the revolver muzzle never faltered. "an interesting stalemate," the man said calmly. "you can thrust, but no matter how fast you are, i can shoot. so, if i die, so does your friend. now, since you created this situation, how are you going to get out of it? or did i create it, through my careless eagerness? i was so pleased to find the hall empty that i forgot there were two of you." "no matter," scotty informed him. "we can stand like this until help comes." "then you expect someone. make no mistake, i will not be taken. if necessary, i will end the stalemate with a shot and take my chances with the knife. it is even possible i will get both of you." rick was watching the man's face closely. he was not bluffing. there was no sign of sweat or nervousness. he knew the situation exactly, and was prepared to deal with it. the boy reached a decision. "drop it, scotty," he commanded. "pull back and come around so he can see you. i'm going to give him the cat." "don't!" scotty exclaimed. "don't, rick!" "i'm going to give him the cat," rick repeated. "it isn't worth bloodshed. now co-operate, will you?" scotty drew back and walked around so the stranger could see him. with a gesture of disgust he threw the nail file on one of the twin beds. the stranger smiled his appreciation. "a very good try. it would have worked, no doubt, on a less experienced man. now, mr. brant, where is the cat?" "in my pocket, in the wardrobe." the gun muzzle waved scotty to the window at the far end of the room. "out of reach, if you please. i will cover mr. brant just to be sure it is not a weapon that he has in his pocket." scotty obeyed, scowling. rick led the way to the wardrobe. moving slowly and carefully, he got the concrete kitten and held it up. "excellent. i see the hotel has provided you with a newspaper. please use it to wrap the cat." rick did so, and handed it over. "thank you. i appreciate your co-operation, since i am a man who detests unnecessary violence. you have acted wisely." he backed to the door, opened it, and closed it behind him. rick's eyes met scotty's across the room, and both grinned widely, but they said nothing in case the stranger had lingered outside the door. not until a few moments had passed and rick had checked the hallway did he speak. "well," he said happily, "one orphan kitten has found a happy home!" chapter x the great pyramid parnell winston faced the group of egyptian scientists in the crowded radio-telescope control room. rick and scotty waited impatiently for the scientist to begin. they knew something important was coming up, from remarks dropped by winston earlier, but they didn't know what. "gentlemen," winston began, "i and my young associates came at dr. kerama's request because of the assumption that internal or local difficulties had caused the strange peaks in your sanborn tracings of the first tryouts of the new system. the assumption was a natural and logical one. however, we have demonstrated that it isn't true. the system is working so perfectly that i must congratulate you. it is seldom that anything so complex functions as well in the early stages." winston paused thoughtfully. "of course dr. kerama realized that it would be highly unusual to have internal circuit trouble cause such signals. but what we have left, after eliminating the possibilities of both internal and local interference, is something even more unusual. in fact, it is fantastic." rick moved forward a little. he didn't want to miss any of this, because he knew winston, and he had never before seen the scientist so excited. "what we have is a source of neutral hydrogen out in space, over five thousand light years away from earth. this source is moving at such incredible velocity that it is very close to the speed of light." there was a stunned silence in the room. rick considered the implications of winston's statement. the scientist had spent hours with kerama and farid going over the sanborn tracings, checking the location of the source as shown by the big telescope's position. the change in the source's position, from the time of first discovery to yesterday's checking of the system, had given enough data to calculate its velocity with reasonable accuracy. the big unknown was the precise distance of the source. readings from a single position could not give distance with high accuracy, so the scientists weren't sure of their figures--yet. winston asked, "dr. kerama, do you want to explain what we have decided?" the egyptian scientist nodded. "thank you, dr. winston. and thank you on behalf of all of us for determining that our mystery does not come from the receiver system itself, or from nearby." kerama faced the group. "last night i sent cables, giving detailed information on times, locations, and our computations to the radio-telescope stations at manchester, england, and green bank and goldstone in the united states. i also, at dr. winston's suggestion, sent similar information to the mount palomar observatory. "if the other radio telescopes are able to participate, it will serve to confirm or disprove our own information. if confirmed, we will then have a precise fix on the source that has caused us so much concern. we will also have the benefit of continuous consultation with our american and english colleagues. at the same time, the two-hundred-inch telescope at palomar will attempt to see this strange object and to photograph it." rick knew of the huge american radio telescope at green bank, west virginia, and the smaller one at goldstone lake, in california. both had tracked space probes to incredible distances. the manchester telescope, more generally known as jodrell bank, had also tracked probes. with a team like that working along with sahara wells, results ought to be coming fast. dr. kerama continued. "we have been so concerned with what we thought was a problem that we have not accumulated all possible data on this hydrogen source. we will start at once to do this. the first step, of course, is to determine how long it is within view of our antenna, so that we may set up a schedule. the next is to obtain as much material as we can on the 21-centimeter wave length. after that we will shift to other wave lengths to see if the source is emitting. dr. farid will make assignments." farid stood up. "a radio-teletype circuit will be installed at once. work is already in progress in the city, and we should have installation crews here within an hour or two. that will enable us to keep in touch with the other stations. for now, i would like dr. mandarawi and dr. azrar to establish the time when the source will be within our horizon, and set up the necessary data for the operator in charge of each shift. the rest of us will check out the circuit and establish calibration to be ready for recording this afternoon." the scientist gestured to rick and scotty. "we know that the source will not come up over our horizon until about one o'clock. when it does, we would appreciate your help in making audio recordings. until then, you're on your own." "what'll we do?" scotty asked. rick looked at his watch. it was shortly after nine. "why not go over to see the pyramids? then we can have lunch at the mena house and come back in time to go to work." "good idea. better tell winston, though, in case something comes up." rick did so, and the boys went outside to where hassan waited patiently. they told him their plans and got into the little car for the short drive to giza. "i got some of that, but not all," scotty said. "give me a brief rundown." "okay. i'm no expert, but i think i got the drift. to start with, the most common thing in space is hydrogen gas. it gives off energy that can be detected on the 21-centimeter wave length. this is important to the radio astronomers, because they can use their telescopes to figure out how hydrogen is distributed throughout the universe." "i'm with you," scotty said. "now our boys have proved that the funny signals in the hydrogen impulse they've been getting originate in space, and hydrogen shouldn't act like that." "that's it. also, a hydrogen source in space ought to stay fixed. but this one is shooting off at high velocity. that would be strange enough, but it's also giving off signals that don't seem natural." "so the scientists yell for help from their colleagues in america and england, and perhaps someone can figure out what's causing this strange behavior?" "on the button, ol' buddy." scotty grinned. "it will probably turn out to be an egyptian space cat mewing for milk from the milky way." rick patted the kitten in his pocket. he had replaced the one turned over to the intruder the night before. now, as he told scotty, only two orphan kittens needed homes. but placing the kittens didn't answer the questions that puzzled him. why was the egyptian cat important? and who were the people that wanted it? there were things about the mystery that didn't add up. for instance, fuad moustafa had written a polite letter claiming the cat, but strictly impolite and violent efforts had been made to get it. and where were the brothers moustafa? hassan drew to a stop before the great pyramid of khufu. "we here. want to go in?" "in a while," rick answered. "we'll take a look around outside, first." the boys got out of the car and gazed upward at the incredible pile of masonry. the blocks were huge, weathered by centuries of wind and sand. once the whole pyramid had been covered with a smooth facing of stone, but much of it had been destroyed by thieves trying to find the entrance to the pharaoh's tomb. rick saw that the top of the lowermost course of blocks was covered with chips of the weathered stone. he picked up a couple and put them in his pocket. his rock collection at home could use a genuine piece of pyramid, and his sister barby would like one for a paperweight. "this could be climbed," scotty said, gazing upward. "oh, yes," hassan affirmed. "some guides go up to top all the time. can show you best way. you want to go?" "not now," scotty said. "let's look around first. but i'm going to climb this before we leave." "and i'll be with you," rick said. they reached the corner of the pyramid and rick sighted along the edge. the thing that impressed him most was the size of the individual blocks. photographs were usually taken at sufficient distance to show the entire pyramid. at that distance they looked pretty smooth. close up, it was a tremendous jigsaw puzzle of blocks that weighed tons. rick had expected a considerable number of tourists and guides, but apparently it was too early. down by the sphinx he saw a few arabs, but no foreigners were in sight. he was glad they could see at least a part of giza before the crowd arrived. "take us inside, hassan," he requested. "can do. you follow." hassan led the way to the center of the side. high above their heads, he pointed to a hole. "up there." the three climbed through tumbled blocks to the opening and paused to look around. this was not the opening the pharaoh had intended. it had been made by thieves, centuries ago. by boring downward at an angle, they had intercepted the inner passageways that led to the buried king and his treasure. electric lights were strung along the corridor at intervals, but the passage was far from bright. hassan led the way, with rick following and scotty bringing up the rear. scotty's voice reverberated in the stone passageway. "i've been thinking that you ought to be just about overcome with happiness. two mysteries on your hands, one detective type and one scientific type, and now you're walking into the middle of a few million tons of rock. how full can life get?" rick grinned. "and you're not happy at all. just came along for the ride, i suppose?" "oh, i'm happy. but i'm a simple soul. one mystery at a time and plenty of chow is all i need." they left the tunnel cut by the thieves and found themselves in a broad concourse with high ceiling and walls that still held the remnants of ancient decorations. rick's vivid imagination could picture the scene as it must once have been, with torches lighting the route as the mighty khufu was carried by richly clad slaves along this route to the inner crypt. hassan pointed to where a side passage led upward. "room there. queen buried, but nothing now. all gone. thieves take." this was the story of egypt. few tombs had been found intact. that was why finding tut-ankh-amon had been of such importance. most of the burial places of the pharaohs had been found and looted many centuries ago. one such tomb would make a band of thieves and their descendants rich. but while the thieves had grown fat, history had suffered. each rifled tomb meant quantities of historical materials lost forever. scotty held up a hand. "someone coming." "more tourist, maybe," hassan offered. rick looked around. in the echoing chamber it was hard to tell the direction from which the footsteps were coming, and whether it was one person or many. hassan was probably right, he thought. it was late enough in the day for tourists to be arriving. and on the heels of the thought, arabs erupted from the entrance through which they had come! there was less than a second of doubt. the men were after them! rick saw scotty crouch as an arab charged, saw the arab go headlong through the air as scotty caught him in a judo throw. then rick and hassan were fighting for their lives! an arab rushed at rick, arms widespread, and the boy stepped between the arms and threw a short punch that caught the attacker squarely on the nose. blood spurted and he let out an anguished yell, then rick put a foot in his stomach and heaved. the man flew backward, arms flailing, and landed on top of one who was grappling with hassan. the guide took advantage of the break to grasp his second assailant around the middle and dump him. the guide kicked expertly and the arab lay still. scotty was backing away from two of them when rick charged to the rescue. he hit one from behind, his shoulder taking the man at the knees. the arab slammed forward. scotty jumped in and grabbed his second attacker by the burnoose, then fell backward with him and flipped. the arab flew through the air like an ungainly bird and slammed into the farther wall. rick choked back a yell of despair as three more arabs charged through the passageway. they were hopelessly outnumbered now. he saw hassan with an arab's throat between his hands, and he saw another attacker coming up on the guide from behind, a knife in his hand. there wasn't time to reach hassan. rick had only one weapon. he plucked the concrete kitten from his pocket and threw, his whole body giving the flying statue speed and direction. it caught the knife wielder where his headdress met his ear. he dropped as though hit with an ax. the kitten fell to the stone floor and shattered. three arabs hit scotty at the same time. rick dove headlong into the fray and got his hands around a stubble-covered face. he put a knee in the man's back and wrenched, but the arab turned like a cat and reached for his throat. a voice yelled in arabic. miraculously, the arabs fell back. as rick and scotty got to their feet they saw the burnoosed figures raise hands high. [illustration] at the passage entrance was a man in western dress, an egyptian with a bristling mustache and a tremendous nose. he was obviously a person of authority, and the authority was made plain by the luger automatic pistol he held in his hand. the arabs crowded together, hands high. then, at another sharply spoken arabic phrase, they all lay face down on the floor, arms stretched out before them. at that moment the newcomer's eyes caught sight of the broken kitten on the stone floor. he stiffened, and he took a step toward it. then he reconsidered. "mr. brant, or mr. scott," he commanded. "one of you only. bring me the pieces of the cat!" chapter xi third brother smiles rick was nearest to the broken kitten. he went over and picked up three large pieces. there were a few smaller ones, but he didn't think they would matter. he walked over and held the pieces out. the man with the pistol took one and examined it. rick noted that it was the biggest piece, actually over half the cat. suddenly the man smiled. it was a fine, happy smile that showed white teeth under his black mustache. "a fine specimen," he said. "where did you get it?" "it just sort of came to us," rick evaded. "indeed? a pity it was broken. do you want the pieces?" this surprised rick. he stared into the smiling brown eyes. "no. don't you?" "i have a definite interest in cats, but not in this one. come, shall we go to the outside? i think you have probably had enough of khufu's tomb by this time, eh?" the pistol motioned to the outstretched arabs. "this carrion will not bother us. i told them the first man to step outside the pyramid before an hour has elapsed would be shot." to rick's astonishment the man tucked the pistol into a capacious jacket pocket, then turned and walked toward the outer entrance. rick, scotty, and hassan followed. in a few moments they stood blinking in the sunlight. their rescuer gave them a polite bow. "you are probably wondering who i am, and how i appeared so opportunely, eh? allow me to introduce myself. i am kemel moustafa." the brother of ali and fuad! rick remembered the words of the hotel intruder who had taken the first kitten: the moustafas were known for the largest mustaches and noses in the united arab republic. well, the description fitted. "i'm rick brant," he said. "this is don scott, and our guide, hassan." kemel moustafa shook hands all around. "i am thirsty," he announced. "we will exchange stories over coffee, eh? the mena house is close by, and i have a car." "so do we," rick said. "we came in hassan's car." "then let us drive down in our separate cars and meet there. we have much to talk over." that was an understatement, rick thought. he wondered as hassan drove them to the hotel below the pyramids: had the business in the pyramid been staged so kemel could come to the rescue? if not, that meant two different groups were interested in the cat. the way kemel moustafa had looked at the broken kitten was revealing, too. one glance and he had rejected it. how had he known? he put the question aloud to scotty. "maybe it didn't break like plastic," scotty guessed. "or, it's possible the original is unbreakable." rick didn't think either of those answers could be the right one. "could there be something inside the cat? kernel would have seen right away that the broken one was solid." "there's a hunk of lead in the cat, according to bartouki. but suppose you're right, and it isn't lead? what could be valuable enough to cause all these wild goings-on?" "diamonds. rubies. maybe a radium needle in a lead shield. the possibilities are endless." "uhuh. only one thing bothers me a little. why use a plastic cat as a container to smuggle things into egypt? there must be better ways." "this way hasn't been very successful," rick agreed. "anyway, here's the hotel. let's ask kemel moustafa." over coffee, rick asked the third moustafa brother many questions, and received answers to most of them--although the answers were not always satisfactory. moustafa anticipated some of the questions. as the waiter brought coffee, he pulled out his wallet and showed the boys his identity card, driver's license, and business card. clearly, he was kemel moustafa. "i have been to khartoum on business," he said. "last night i returned to the city and found that a family emergency had taken both of my brothers out of town. fuad left very suddenly, after he had written to you. i apologize on his behalf. however, he must be excused, since a call from ali, in beirut, sent him running to the airport to catch the next flight. he simply had no time even to call you. his secretary tried to call you today, without success." "we wondered," rick said. "of course. and you are also wondering how i came into the pyramid at just the right time. a fortunate accident. you see, i came to sahara wells hoping to see you, but you were sightseeing. dr. winston was kind enough to tell me where you were. i simply went hunting for you. a quick drive around the area told me you must be in one of the pyramids, and the biggest one seemed the most logical place to look for you." rick believed him. moustafa wouldn't tell a tale that a moment's talk with winston would disprove. "who was the man who pretended to be your brother ali?" scotty asked. "his chief clerk. he is an arrogant type who often shows poor judgment. instead of simply explaining to you that ali was out of town, he apparently told you he was ali. this was the case?" rick confirmed it. "he will be discharged at once. i suspected it when i questioned him last night. he gave some lame excuse about your refusing to hand over the cat to anyone except my brother ali. he told fuad the same thing, according to his secretary." "it wasn't such a lame excuse, mr. moustafa," rick corrected. "mr. bartouki asked us to deliver the cat to ali moustafa. we have no instructions to deliver it to anyone else." "i see. and i commend your discretion. but my brother ali will not return for many weeks, and you will not want to take the cat back to america with you. so we will telephone mohammed bartouki, and you will hear directly from him that i am a suitable substitute for my brother." scotty asked bluntly, "why is the cat so important?" moustafa spread his hands wide. "why not? the creature will open a new industry in cairo. it will employ a number of people. it will make a profit for the moustafa-bartouki enterprises. it will please the tourists. obviously the cat is important." rick tossed in his loaded question. "how did you know the cat in the pyramid wasn't the cat we brought from america?" kernel moustafa's thick eyebrows went up. "it was obvious, was it not? the broken cat was made of colored concrete. the cat bartouki took such pains to develop was of a plastic that does not have the graininess of concrete. if you tell me the one in the pyramid was indeed the original, i will be very disappointed. such a model would not be suitable." "it wasn't," rick said briefly. "ah. and where is the original?" rick's smile was every bit as warm and friendly as kemel moustafa's. "perhaps the answer to that had better wait until we have talked to bartouki." the egyptian's smile broadened. "discretion in one so young," he proclaimed, "is a rare and precious thing." he put money on the table for their coffee and rose. "you will excuse me? i have business in the city. but tonight at seven i will come to your hotel and we will phone our friend in new york. it will then be noon in new york, and we will find him reading the koran at home. this is his custom. until then, _assalamo alaikum_, which is to say, 'good day to you.'" as the boys walked to where hassan waited, scotty grinned at rick. "'discretion in one so young,'" he quoted, "'is a rare and precious thing.' he should know you as i do. discretion has nothing to do with it. you just don't want to part with that cat until you know everything there is to know about it." rick shrugged. "i haven't heard you volunteering to hand the poor creature over. besides, our pal kemel is not all that he seems." "and how do you know?" "easy. did he ask us who jumped us in the pyramid, or why? did he explain why he carries a luger? nope, to both. he carries a luger because there's danger in this business. and he knows why those arabs jumped us. he may not know them by name, but he knows what they were after, and he knows why." "which is more than we know," scotty concluded. "for now," rick agreed. "but we'll find out before we're through, one way or another!" chapter xii third brother stops smiling rick opened the door to a knock at precisely two minutes of seven, and admitted kernel moustafa. the egyptian shook hands politely. "it takes some time to get a call through," he said, "so i placed our call an hour ago. the operator assured me it would go through precisely at seven." moustafa turned to scotty and shook hands again. "according to my watch, we have only a few seconds to wait. mr. brant, you will answer the phone, if you please. identify bartouki to your own satisfaction, then ask him about kemel moustafa. then turn the phone over to me, and i will talk with him. after that you take the phone back again, and he will give you final instructions. this is acceptable?" "absolutely," rick said. he thought quickly. how could he establish bartouki's identity for certain? then, as the phone rang, he knew. rick answered. "rick brant speaking." "on your call to new york. mr. bartouki is on the line. go ahead, please." rick raised his voice instinctively. after all, new york was a long distance away! then he realized that electronic facilities reduce the need for shouting, and lowered it again. "mr. bartouki? this is rick brant." "good morning, rick. ah, but this is evening in cairo, is it not?" rick was sure he identified the little merchant's voice, but he went ahead anyway. "mr. bartouki, please forgive me, but i must establish your identity beyond any doubt. can you tell me what color dress my sister barbara wore at your reception, and the color of her hair and eyes?" "of course. her dress was a very attractive blue wool with a red leather belt. she is very blond, with dark-blue eyes, and she is about my height." rick was satisfied. "thank you, sir. the reason i had to be careful is this. we went to ali moustafa's shop, and a man who did not answer your description of ali moustafa pretended to be him. we refused to give up the cat. then our room was searched. we received a letter from fuad moustafa, and when we went to his house it was padlocked. last night a man came to our room with a pistol and demanded the cat. we gave him a copy we had made in concrete. i should add we also were attacked in front of the egyptian museum by men who searched us. that was why we made the copies in concrete. the real one is hidden. then, this morning, we were attacked again, inside the pyramid. we were rescued by kemel moustafa. he is here with us now. if you approve, we will give him the cat. if not, tell us what to do with it." bartouki's voice sounded incredulous over the ocean miles. "this is incredible! i must know the meaning of this. may i speak to kemel?" rick handed the phone to the third brother and listened. kemel launched immediately into a rapid flow of arabic. scotty interrupted, "can you speak in english please?" kemel stopped abruptly. "of course. forgive me." he spoke into the phone. "your young american friends want me to speak in english, mohammed. they are cautious, and they have reason. i did not know of their room being searched, the man who came with a pistol, or the attack in front of the museum. i arrived this morning because i had gone to the radio telescope to look for them.... yes ... yes, most certainly i will try to find out who has caused them such trouble. ali and fuad are in beirut. it is because of our father. you know that he has been very ill? yes, by all means send a cable. it will be appreciated. and now, if you will tell mr. brant ... yes ... _ma'e salamet ellah_, mohammed. allah protect you." moustafa handed the phone to rick. the boy said quickly, "yes, sir?" "my dear boy, i am very upset by this affair." bartouki sounded agitated, even across the miles. "kemel will try to find out what has been going on. meanwhile, please give him the model. and accept my apologies for getting you into such a situation, and my thanks for your loyalty to our model cat. i hope to show my appreciation when you return, and i shall certainly want to hear all about this. but for now, trust kemel. he is my friend and associate." rick promised to do so, said good-by, and hung up. he turned to moustafa and scotty. "mr. bartouki agrees. we turn the cat over." kemel stroked his mustache. "yes. but first, i must know of these attacks. can you describe the men who attacked you at the egyptian museum?" scotty could, and did. he gave complete details of dress and appearance. the egyptian shook his head. "i'm afraid the descriptions mean nothing. they did not harm you?" "they could have," rick stated. "but they only searched us. we didn't have the cat with us, and it took only seconds for them to find out." moustafa's brows creased. "i can make no sense of this. why would anyone want the cat?" rick and scotty laughed mirthlessly. "that's exactly the same question we asked ourselves a thousand times," rick said. "and you made copies of concrete? that was extremely clever of you. i believe you gave one to a man who showed up here?" rick described the encounter, and he gave a detailed description of the man. before he was through, moustafa was nodding his head. "i recognize this man! from your description, it can only be one youssef. he is a well-known thief, and the leader of a gang. my brother fuad was once requested to defend him, and refused. another lawyer with less scruples took the case and got him off." "but why would a thief want the cat?" scotty asked. moustafa shook his head. "i do not know. unless he intends to sell the model to a manufacturer, or to produce cats for sale himself. or, if he knows how much time, money, and planning we have invested in this cat, he may see it as a means of revenge on the moustafas because fuad would not take his case." the answer was logical enough, but it didn't ring true to rick. at least the revenge part didn't. what had youssef said? "_i have no sentimental attachment to this object. i merely want it._" a motive of revenge would be emotional, even if not exactly sentimental. "why do you carry a pistol?" rick asked suddenly. it took moustafa a moment to reply. "i have enemies," he explained. "i will not bore you with an explanation of why this is, but the reasons are not related to this cat." "how did you know the cat in the pyramid was not the right one?" scotty demanded. moustafa studied the boy for a long moment before he replied. he shrugged. "i have been a contractor. i know concrete. the cat you brought is of plastic, which does not break. or, if it does, it breaks differently. from your questions, i see you still harbor suspicions. was not bartouki's word enough?" "it was," rick said. "only we'd like to know about these attacks. who were the men, and why did they want the cat?" "then my explanation does not seem sufficient. i am truly sorry, because we are in your debt. but i cannot tell you more, because i know no more. the only thing i can do is talk to some people i know who may have more clues to youssef's behavior." moustafa's attitude changed subtly. "now, where is the cat?" rick was suddenly glad he didn't have it at hand. "it's in the egyptian museum," he said. moustafa exploded. "what!" "that's right," scotty added coolly. "we saw the men trailing us, so rick hid the cat in the museum. if he hadn't, the thieves would have it now." moustafa sank down into a chair, a hand to his forehead. "but this is terrible! we can never recover it! surely by now the museum curator has it." rick shook his head. "i don't think so. and i'm sure we can recover it." "but how? guards swarm everywhere. they are alert, because there was a big robbery not long ago. everyone is watched. everyone! i don't understand even how you could hide it without being seen." "we have our own methods," rick assured him. "and we'll get the cat back. if you will come here tomorrow night it will be waiting for you." moustafa rose and walked to the door. he looked at the boys, and above the luxuriant mustache, dark eyes blazed at them. "it had better be," he said flatly. "if you are caught by the museum guards you had better say it was a joke. as americans, you may be believed. do not connect me, or my brothers, or bartouki with this thing! but get that cat! i don't care how. but get it!" he slammed the door behind him. rick looked at scotty. "get it, or else?" "or else," scotty confirmed. "he didn't say it, but he meant it." rick put his thoughts into words. "no one gets that excited over a plastic model. the cat is important for some other reason. but what?" "i'll ask a different question for a change. who would you rather have on your trail, moustafa or youssef?" rick stared at his pal for a long moment while he digested the implications of the question. "i see what you mean," he said finally. "there are two groups after the cat. right? i've wondered about that myself, since we were rescued by kemel this morning. so we're caught between a pair of tough characters, like eggs in the jaws of a vise." scotty finished grimly, "and right now the jaws are closing. fast." a thought struck rick and he grinned. "how about scrambled eggs for new year's eve dinner?" "what?" "it's new year's eve." scotty reached in his pocket and found a pocket calendar. he consulted it. "hey, you're not kidding!" "nope. so, as the year closes, where are we? caught between kemel and youssef." "maybe next year will bring better things," scotty said with a grin. "uhuh. but for whom?" "that," scotty said, "remains to be seen!" chapter xiii the space mystery there was an air of excitement at the project when the boys arrived there the following morning. everyone was busy on equipment, or studying sanborn tracings. winston and kerama were working a slide rule while farid read figures. the boys waited until winston gave a number, which kerama marked on the pad he carried. then the scientist looked up and gave the boys a big grin. "happy new year both of you! interesting news this morning. take a look at these." they were teletype sheets. rick saw that a machine was now in one corner of the control room, where technicians had finished installing it during the night. he and scotty read the messages. translated from the cryptic notations and abbreviations used by the astronomers, it added up to confirmation of the egyptian findings by both jodrell bank and green bank. both reported that they had also located a source of apparently modulated hydrogen impulses. both gave the same co-ordinates in space, in terms of ascension and declination, the way astronomers locate the position of heavenly bodies. both stated that the finding was remarkable and requested all available data from sahara wells, and both announced their intention of concentrating on the object while it was in "view" of their radio telescopes. rick looked at winston, his eyes shining. "boy! we're on to something big. what's the next step?" "next is a precise fix and distance computations by all stations. at the same time, we want two kinds of recordings. we'll continue making sanborn tapes, but we also want audio-tape recordings." "you want to actually hear this thing?" scotty asked. this was unusual, since the radio telescopes ordinarily recorded the incoming signals in trace form on sanborn strips. "we don't want to overlook any possibility," dr. kerama said. "this is without precedent, and we are not sure how to proceed. dr. farid has set up an amplifier on the output circuit, in parallel with the normal system, and he has brought in a pair of tape recorders we borrowed from the government radio station. it may be that listening to this signal will give us clues that our eyes miss when we examine the tracings." winston added, "that's your job. i intended to keep you here together, a half day at a time. but this is too important for such considerations, and we haven't a large enough egyptian staff to handle everything. so i'd like to work you in shifts." "that's okay," rick assured him. "when do we start?" "the object comes up on our horizon shortly after one. suppose you start then. the first shift can work until five, and the second from five to eleven. one of the egyptian technicians will take over then until we lose the source below the horizon again." hakim farid took the boys to the tape setup he had established and explained it to them. it was simple enough. the output signal from the receivers was fed into a regular tape-recording circuit. the tapes themselves were on huge reels good for about four hours of recording. it would only be necessary to watch the volume control and to see that all was running smoothly. changing tapes was only a matter of slapping a new reel into place, dropping the tape into the recording head, and threading it into the empty reel. "how will we work it?" scotty asked, while they rechecked the setup and tried out the tape motors. rick frowned. "it kind of throws a monkey wrench into our plan, doesn't it?" he and scotty had worked out a way to recover the egyptian cat, again with scotty distracting the guard. "one of us will have to get it alone," scotty said. rick watched the tape run through and searched his mind for a method. there was only one way he could think of that would get the guard out of the way. "looks as if that third kitten is going to have a home," he said finally. "i'll wrap it in an old newspaper, then pretend to find it under something. i'll hand it to the guard. with luck, he'll get so excited he'll run for his boss, thinking someone has tried to steal a museum exhibit. then i'll snaffle kitty off the shelf and hike out." scotty rubbed his chin. "could work," he said finally. "unless the guard insists that you go with him." "no speak arabic," rick said. "i won't understand. let's hope the guard speaks no english." "well, if anything goes wrong, moustafa will just have to wait. so i'll take the first shift and you go get puss. that means i'll be waiting for ol' kemel alone tonight at the hotel." "looks that way." there seemed to be no solution except to turn the cat over. bartouki had approved, and the cat was his. much as the boys hated to let go of an unsolved mystery, there wasn't any other way. hassan drove rick back into town, with the boy sitting in back. he would have preferred to be in the front seat with the dragoman, but the taxi meter took up too much room. the guide parked directly in front of the museum and asked, "i go with you?" "not this time, hassan. i won't be long." if rick's trick was to work, no translator should be at hand. he paid his piastres at the entrance and walked into the huge entrance hall, very conscious of the kitten in his pocket. it was wrapped in a week-old copy of a newspaper recovered from the debris around the new barracks. when he reached the second floor he acted like a casual museum visitor, taking his time, and working from exhibit to exhibit. but his mind was not on the wonders of ancient egypt. it wasn't much use to think about the cat, either. all the ground had been covered many times. instead, he spent the time speculating on the meaning of the mysterious signal from space. admittedly, he didn't have much knowledge of astrophysics or radio astronomy. but he had never heard of any natural phenomenon in space that emitted pulsed signals in random fashion. some stars pulsed, like the cepheid variables, but in an orderly way. a half hour of speculation led him nowhere so far as the space mystery was concerned, but it did bring him slowly to the museum area that interested him. he nodded politely at the guard, and continued his examination of exhibits, moving finally into the little room where the cat was hidden. soon he was close enough to see that the egyptian cat and its antique friend were still in place. he continued on around the room until he came to a glassed-in case that held some rare alabaster figures. directly before the glass case was a stone jar. it was big enough to hold the kitten. rick got ready. his coat was unbuttoned. he put a hand in the outside pocket, ready to swing the coat out so his other hand could remove the kitten from the inside game pocket with one swoop. he watched the guard, using the glass-case front as a mirror. the guard bent his head to light a cigarette, and rick moved. by the time the cigarette was going well, the kitten was in the jar and rick was looking at the figures in the case again. he waited patiently, and tried identifying the figures so he would seem to be genuinely interested. the figure with the stylized jackal head was anubis, the god of death. the hawk-headed one must be horus. the female figure would be isis. the one with the solar disc over his head was probably amon-rã©. the rest he couldn't identify at all. he wondered if one of them was bubaste, the cat goddess. it would be appropriate. he drew back a little, first checking to see if the guard was watching, then he bent down and looked into the jar. he put a hand in and brought out the newspaper. he turned it over and hefted it. then he started to unwrap it. the guard was at his side in a flash, watching. the reddish form of the cat came into view and the guard snatched it from his hands. rick turned to him with a look of bewilderment. the guard unwrapped the kitten completely and held it up, then he turned swiftly and hurried out. rick was across the room in two bounds. he grabbed the egyptian cat and tucked it into his inner pocket, then he closed his coat without buttoning it and hurried after the guard. the guard hadn't gone far. rick found him with another guard, gesticulating and waving the cat. apparently the other guard was an officer, because he had tabs on his shoulder. the guard with the cat saw rick and beckoned to him. he walked over, trying to keep his expression interested but unconcerned. the officer spoke english, but not well. "he say you get this?" "i see in big jar. vase. stone. in newspaper. someone leave?" rick did his best to make his reply simple enough for understanding. he apparently succeeded. "think someone try steal. bad." "very bad," rick agreed, straight-faced. "hope you find. steal from museum no good." "no good," the officer agreed. "good-by," rick said. he held his breath waiting for the reaction. both guards gave him a half-salute, the courteous gesture he had seen often in cairo. he bowed and walked toward the stairs. not until he was outside did he breathe freely. the cat was a comforting weight in his pocket as he got into hassan's car. he wondered what the museum officials would think about the kitten. a moment's examination by one of the archaeologists would show that it was of concrete, and new concrete at that. maybe it would just end up at the _lost and found_ desk, if they had one. "let's go back to the project, hassan," he directed. scotty would want to know if he had been successful. then he could go to the mena house and have a late lunch while scotty recorded signals. if only he didn't have to give the egyptian cat to moustafa--until the mystery was solved. he grinned at his own thought. the cat was no good to him, was it? his only interest was solving the mystery. why did so many people want it? he forced himself to think logically. it was old ground, but he went over it again. the cat itself could have no real value. it was plastic, and plastic is cheap. on the other hand, it was valuable as a model, as bartouki had explained, and moustafa had confirmed again last night. rick wasn't satisfied. a professional thief like youssef wouldn't be interested in a model. he would want only objects of high value. there was only one possibility, which rick and scotty had considered before, that the cat contained something more than the piece of lead bartouki had described. but there was no seam in the cat, no sign that it was anything but a solid casting. still, rick reasoned, if a piece of lead could be cast into it, so could something of greater value. he had it! somewhere in cairo there must be a company that used x-ray or gamma-ray photography to check large castings. it was a very common method of industrial quality control. farid or kerama would know of one, and he could arrange to have the cat x-rayed! it could be done immediately. pleased with the idea, he paid attention to his surroundings for the first time since leaving the museum. hassan was just rounding the corner by sahara wells, turning into the new spur that led to the project. ahead, across the road, was a caravan of camels. rick watched, interested. there were a dozen camels, and arabs in burnooses. some of the camels seemed to be carrying loads. like a movie, rick thought. hassan slowed, tooting his horn. the group on the road paid no attention. they weren't going to get out of the way for any old gas burner, rick thought. not these traditional ships of the desert. the car closed the gap, and one of the arabs turned. rick gasped. under the desert headdress a pair of eyes were looking at the car through steel-rimmed glasses. youssef! and youssef wanted the cat! chapter xiv the broad sahara there was no way around the caravan without going into the desert, and the car was too close to turn around. they were trapped! rick hurriedly took the cat from his pocket and stuffed it down behind the cushion of the car, pushing until it was well hidden. he knew he would be searched; why else would youssef come? he hoped a search was all there was to worry about. hassan leaned out of his window and shouted imprecations in arabic, to which the arabs paid no attention. they closed around the car, and rick recognized two who had taken part in the attack at the museum--the sudanese and the big egyptian who had worn a tarboosh. he also recognized the one he had beaned with the kitten in the pyramid. he was not among friends, he thought grimly. youssef opened the door. "please get out," he requested. "it will be easier if you co-operate." rick looked at the odds and had to agree. he got out. hassan was right behind him, still shouting in arabic. an arab stepped up behind the guide and slugged him. rick started to yell a protest, then a burnoose was tossed over his head and wrapped tightly around his chest, blocking out the light. he struggled, and was pushed to the ground. in a moment he was rolled over and knew they were wrapping him in a blanket or a rug. he felt pressure as ropes bound him tight, then he was lifted and placed on something hard, stomach down, like a sack of meal on a chair. the chair lifted and rocked, and he heard loud groans, as though of a soul in mortal pain. he was on one of the camels, and the beast was protesting! swaying motion began, and he knew his ungainly steed was underway. for a moment he seemed to see himself from a distance, wrapped like cleopatra in a rug, tossed on a camel like a bag of old clothes, and carted unceremoniously away by a band of arabs. the picture was so ridiculous that he had to grin, in spite of the discomfort and the foul air that reached him through the dirty burnoose. then realization hit him. youssef was in charge, and youssef was a tough professional thief who intended to get the cat. where was the thief taking him? sudden fear ran through his thoughts. the camel swayed and jogged along for what seemed hours to rick. now and then he could hear voices, but he made no sense out of the arabic. the camels complained constantly, and he felt like moaning with them. his stomach hurt from the constant rubbing across the saddle and both legs were asleep from the tight wrapping. his head dangled down, and now and then his nose banged when the camel lurched. he couldn't remember ever having been so uncomfortable for so long. it seemed forever before the camel stopped. rick hung over the saddle unprotestingly. there was nothing he could do but wait. finally the camel lurched forward and rick thought he would be thrown off, then the animal leveled again. the camel had knelt, still complaining. hands pulled rick from the saddle and he felt someone at work on his bonds while the hands held him upright. suddenly the burnoose was whipped off, and the brilliant sunlight made his eyes water. he squinted against the glare. [illustration: _hands pulled rick from the saddle_] an arab finished unwrapping him and stood back. he would have fallen except for the hands that still held him from behind. he looked over his shoulder and the big sudanese grinned at him. he didn't feel like grinning back. when his eyes were adjusted to the sun, he looked around. there was desert in all directions, no sign of civilization anywhere. immediately before him was an ancient stone structure, nearly buried by the sands. youssef walked around one of the camels carrying a desert water bag. the thief lifted it, and water poured into his mouth in a thin stream. rick licked his lips. "i'd like some of that," he said. youssef recorked the bag. "doubtless," he agreed. "mr. brant, i size you up as what you americans term a stubborn case. however, i am prepared to drop this whole affair right now--if you will turn over the cat without further trouble." "we gave you a cat," rick reminded. "yes. but not the right one." "how do you know it isn't the right one?" rick demanded. youssef smiled. "shall we say that i had a cat expert examine it? let it go, mr. brant. we both know you still have the one i want." "but why do you want it?" rick asked. he couldn't help asking, even though this obviously was not the time for friendly banter. "i want it. that is enough. will you give it to me?" "i can't," rick explained. "it must be turned over to moustafa." he didn't say which moustafa. the thief sighed. "then i was right. you are stubborn. well, stubbornness is like starch. it does not last. in this case, we will let the desert and thirst take the starch out of you. after a few days here you will beg me to take the cat. but it is all so foolish, and so unnecessary! why not be reasonable?" rick looked around at the endless, shimmering dunes of the sahara, and he wanted desperately to be reasonable. he couldn't. "sorry," he said. "very well. on your head be it." youssef called in arabic and two men lifted down a huge bundle from one of the camels. they unwrapped it, and hassan swayed and blinked in the glaring sun. "you shall have company," youssef stated. he gestured at the surrounding wastes. "we leave you to do what you wish. you might even try to walk to civilization. i will leave no guard. however, i do not recommend it, because when i return it might not be possible to find you in time if you should leave here. when i come back i will have writing materials and you will send a note to your friend scott, telling him to give me the cat. when i have the cat, i will see that your friends are told how to find you." the thief swung to a kneeling camel, and his men followed suit. a command and the camels rose, mouthing their complaints. youssef waved, and the caravan raced away with long, smooth strides across the desert. rick turned to hassan. "are you all right?" he asked anxiously. the dragoman put a hand to his head. "hurts like fire, but i okay. you?" "i'm fine." "what we do now?" rick saw the camels disappear behind a dune, then emerge again. it was a pretty, romantic picture, but one he couldn't appreciate. "we wait," he told hassan. "we wait, and i guess we hope. there's nothing else we can do." chapter xv the cat comes back the hands of the control-room clock crept up to five. scotty asked an egyptian technician to watch the tapes for a moment, then went to the telephone and called the hotel. it wasn't like rick to be late. scotty thought his pal might have decided to take a nap and had failed to wake up in time, but he had little faith in the idea. rick wasn't a nap taker. more likely, something had happened at the museum. the hotel desk rang the room without success, and to scotty's question, the clerk answered that he had not seen mr. brant or hassan since morning. scotty debated calling the museum, and decided against it. he went to parnell winston, who was supervising the transfer of information from the sanborn tracings to graph paper. "rick hasn't shown," scotty said bluntly. "i'm worried. he's never late." winston glanced up. "could hassan's car have broken down?" "could be, but i don't think so. rick could have gotten a taxi anywhere on the route. besides, he was going to the museum to get the egyptian cat. something might have happened." the scientist knew the two boys from long association, and they had kept him informed of their various adventures. in spite of his preoccupation with the project he had been interested in their cat mystery and had been keeping an eye on them. winston hadn't noticed that rick was late, but he was worried too, now that it was called to his attention. "go find him, scotty. dr. kerama's driver can take you. i'll have one of the others watch the tapes. but get back as soon as you can." scotty planned his search on the way into town. he had the car take him to the museum as soon as they arrived in cairo. the museum was closed, but questioning of the guard disclosed that rick had been there, and had "found" an unusual statue wrapped in newspaper and left in an urn. it was a new statue, the guard captain said, probably left by some visitor who had disobeyed the sign about taking packages into the museum. so rick had carried out the plan and had rescued the egyptian cat. now the museum had the kitten. scotty had the car take him to the hotel. there was no sign of either rick or hassan, and no one had seen either of them. scotty questioned the clerk, the doorman, the hall porter, the room maid, and the dragomen who waited for business in the narrow street between the semiramis and the shepheard's hotels. finally, he found a dragoman who knew nothing of their whereabouts, but added, "why you not wait in room? they not far. hassan's car here." "where?" scotty demanded quickly. "out back. in alley." scotty ran. the dragoman was right! hassan's car was parked in the usual place. he looked around to see who might have been working in the area, someone who might know when the car had arrived. a window in the hotel kitchen opened into the alley above the car and a cook was looking out. scotty found the door and hurried into the hotel. he worked his way through rooms and corridors until he found the kitchen. he saw that the cook was a salad maker who apparently worked at a bench right next to the window, but to his questions the man shook his head. he spoke no english. additional searching produced the chief cook, whose english was good. he relayed scotty's questions and the cook's answers. "he say car come while he cleaning up after lunchtime. he see stranger driving. so he lean out and ask where is hassan. stranger say he is the cousin of hassan and hassan lend him car. that is all. cousin lock up car and go away." it was enough. but scotty's elation over finding a clue was tempered by the realization that a stranger driving hassan's car could mean that rick and the dragoman were in real danger. he did not know whether or not hassan had any cousins, but he was certain the guide would not have loaned the car while on a job. scotty ran into the alley and tried all the doors. if rick had managed to leave a note or any clue in the car, scotty wanted it. locked doors weren't going to stop him! he searched the alley until he found a piece of stiff wire. he bent one end into a hook. then, with his jackknife, he pried one of the no-draft windows open just far enough to slip the wire in. he wedged the window with a piece of wood and began fishing. it took long, patient minutes to hook a door handle, then more time to maneuver the wire into position. by the time he was ready for the last step, the cooks and some of the dragomen were watching. he paid no attention. holding his breath, he exerted pressure on the wire. the inner handle turned, the latch clicked. the door was unlocked. scotty started in the front seat and went over the car methodically. he found nothing. finally, only the cushions were left. he pulled the front one away and examined the debris that seems to collect under car seats. he put the cushion back and went to the rear one. he lifted the seat out--and disclosed the egyptian cat, in back of the cushion where rick had stuffed it. scotty examined it, his heart racing. he hurriedly set things to rights in the car, closed the car door, and hurried into the hotel. he knew rick, and he knew his pal wouldn't have parted with the cat except for one reason: to protect it. that meant rick had expected to be searched. scotty followed the thought forward, logically. rick had hidden the cat, then he and hassan had been taken from the car. a "cousin" had brought it back to the hotel. why? scotty didn't know the answer to that, unless rick and hassan had been taken in some location where an abandoned car would have attracted attention. that wouldn't be in the city, because who would pay any attention to a car parked and locked at the curb? but if not in the city, where? somewhere in the desert was scotty's guess. the desert was on both sides of the river, both north and south of cairo. he could assume that the two had headed for the project, or that they had gone north for some reason he couldn't imagine. he dropped the line of thought; it was getting nowhere. one thing was clear: whoever had taken rick and hassan hadn't suspected that rick actually had the cat with him. the cat had to be the reason. someone who wanted it had decided on direct action. scotty opened the door of the room he shared with rick and looked about him unhappily, not really seeing anything. he knew rick's captors would not have an easy time making his pal talk. and even when rick did open up, he would spin some kind of yarn that would throw them off the trail. scotty thought that rick would not be in any great danger until he disclosed the cat's whereabouts. but he didn't like the idea of what rick would have to go through before then. the question was who had taken him? there were two possibilities: moustafa and youssef. so far as third brother knew, the cat was to be delivered to him at the hotel that night. on the other hand, youssef's men had searched them in front of the museum, and later rick had handed youssef a kitten. the thief must have found out that the kitten was a fake. scotty picked up the room telephone and called the project. in a moment he had winston on the line. "rick's gone," he said tersely. "hassan, too. the car was brought to the hotel by a stranger. rick left the cat in the car, behind the rear cushion. he wouldn't do that unless he knew he was going to be searched. my guess is that youssef snatched them. i think it's time we got the police in on this!" chapter xvi the howling jackals tourists travel thousands of miles to see the full moon rise over the sahara desert. it is a sight of lonely, majestic grandeur. the rolling contours of sand and rock assume weird, lovely patterns, and even the desert wind is hushed. it is at such times, men say, that the spirits of the ancient egyptian gods, amon-rã©, horus, thoth, isis, osiris, bubaste, and the others again walk on earth. rick brant could appreciate the scene, but he was in no mood for it. he clutched his coat around him more tightly to keep out the penetrating desert chill. from behind a nearby dune he heard the rising, yapping howl of a jackal, one of earth's loneliest sounds. anubis, egyptian god of death, had the head of a jackal, he recalled. he tried to wet his lips. he was terribly thirsty. hassan had been stretched out on the sand. he rose to a sitting position and gestured toward the dune that shielded the jackal from sight. "he noisy." rick nodded. "do jackals always bark at night?" "always. it is their kismet." their fate, rick thought. born to bark at the empty desert. he wondered if the little doglike animals enjoyed it. "do they always bark at nothing?" "no. sometimes they bark at people. like now. he bark at us." rick grinned feebly. "he doesn't like us using his desert. well, i'd be happy to give it back to him." the dragoman nodded. "also. you know, when our people want to say time go by ... how you say? ... life goes on and no man can stop time or make much change in things, they speak of the jackal." rick looked at the guide with interest. he had been glad all through the long hours of hassan's presence. the sudanese had turned out to be an entertaining and thought-provoking companion. "is it a saying of some kind?" he asked. hassan nodded. "the little jackal barks--but the caravan passes." rick repeated the expression thoughtfully. it said a great deal. "i'll remember that, hassan." there was something he had wanted to ask. "may i ask a personal question?" the guide spread his hands expressively. "you hired a dragoman, but he has become your friend. ask what you will." "thank you, hassan. scotty and i think of you as a friend, too. i wanted to ask about your english. you've been speaking very good english to me all day, but until we were captured, you spoke sort of broken english." hassan chuckled softly. "it is part of show i put on. my clients talk too simple english to me most of the time. they don't expect me to know good english. so i do not speak as well as i can. now, with you and scotty, it is different. my broken english is habit, so i continue to speak it until today. but i knew it would be different with you when we had coffee together, and when we laughed together. that was when i knew i could leave my show clothes at home and dress in a suit." rick laughed with him. "so that's why you wore fancy stuff only that first day. but, hassan, if you can't read or write, how did you learn such good english?" "i am like a parrot," hassan replied. "i hear, and i repeat. for four years i was houseboy to an american family, from usis, what you call the united states information service." "they taught you english?" rick prompted. "i knew some, but we helped each other. i teached them arab talk, and they correct me when i speak american." hassan launched into a recital of his years with the americans, who had been transferred to india, but still wrote to him now and then. rick listened with only part of his mind. for the most, his thoughts went back over ground he had covered before, since youssef had dumped the two of them next to an ancient crypt. the big question was, of course, what would happen to them? as though in answer, the little jackal appeared silhouetted on top of the dune. he lifted his head to the full moon, and his voice rose in a prolonged, yapping howl. then, as suddenly, he was gone again. rick gave an involuntary shiver. by the time youssef returned, he would be in bad shape from thirst. he wondered how long he could hold out, and in the same instant wondered why he should. there was some real value attached to the cat. it was not manufacturing rights or sales, and it was not revenge. he was sure of that. youssef had said that he had no sentimental attachment to the cat. he had also said he disliked unnecessary violence. rick wondered what the thief considered "unnecessary." what else could he recall of youssef's talk? he had said that the cat was not important, that it had elements of value to some people, and that he never lied. if one took his words at face value and believed him, then the cat itself was not important. what did that leave? rick could see only one thing: that it was important only because it _contained_ something. youssef's words simply reinforced the conclusion he and scotty already had reached. "elements of value to a few people," youssef had said. that might mean only a few people knew what the cat contained. if you didn't know, it was only a plastic cat. if you did know what it contained ... well, youssef knew, and he wanted the cat badly enough to risk a kidnaping. rick wondered where the cat was now. he had no idea of what had happened to hassan's car. if it was left on the road and not searched, scotty or someone from the project would recognize it. scotty would certainly search the car, and he would find kitty. it was what rick would do, and he and scotty thought alike on many things. hassan finished his recital of a trip to the valley of the kings with his american employers and rick took advantage of the lull to borrow a match. he lighted it and looked at his watch. it was nearly midnight. had scotty met kemel moustafa at seven? rick thought he probably had, and wondered what third brother's reaction to his mysterious disappearance had been. if scotty had the cat, had he delivered it? rick thought not. scotty would keep the cat, for bargaining purposes. he found himself yawning. "hassan, when do you think youssef will come back?" "if he wants us alive and able to talk, maybe day after tomorrow. if not--_la samah allah!_--maybe longer." "what's _la samah allah_?" rick stumbled over the pronunciation. "god forbid," hassan said grimly. "amen," rick echoed. he shifted position. "we'd better get some sleep. should we go into the crypt or stay out here?" the crypt was only a cubic chamber of rough stone, partly filled with drifting sand. desert winds had been alternately covering and uncovering it for centuries. "stay out here until morning. then we go in out of sun, like today. youssef good to us. with no shelter from the sun, we would not last long." "he's a fine fellow," rick said without heat. "good night, hassan." "_leltak s'aeeda_, rick. good night to you." the boy curled up in a ball, knees tucked into stomach, head resting on one arm. he covered up as much as possible with the short coat, squirmed until he had a depression for his hip in the sand, and closed his eyes. on the nearby dune the little jackal peeked over the top at the two prone figures and sang his vast displeasure to the moon. from faraway a friend or relative joined in the serenade. it was the last thing rick heard. * * * * * hassan shook him. "rick! awaken, please! camels coming." rick came back to reality from a dream of emptiness and loneliness in a darkened desert. the moon had set and false dawn was burning on the far horizon. he shook his head blearily. "what? who's coming?" "not know. i woke and saw camels on the sky." "in the east?" "yes. against sky." rick shivered in the biting chill of early morning. he doubted that any legitimate travelers came this way. youssef would not have left them near a caravan route. he could only guess that the thief himself was coming back, and he grew colder at the thought. perhaps youssef had decided not to wait to soften rick up. on the other hand, there was a remote possibility he had the cat. if he was a thief with honor, he might simply be coming to take them back. the idea seemed unlikely. scotty wouldn't give up the cat, except in exchange for the two of them. if youssef had found it himself, it was hours ago. he wouldn't have waited to search hassan's car, if he had ever intended to search it. an inner voice urged, "tell him where the cat is. it's not your cat, and there's no reason to believe that kemel moustafa has any more right to what's inside of it than youssef has." but there was a deep streak of stubbornness in the brants, which rick had inherited. he knew he wouldn't give in until he absolutely had to. when that time came he would tell youssef the truth, that he had hidden the cat in the egyptian museum. what he would not say was that the cat had been recovered and that he had left it in hassan's car. false dawn had faded. it was nearly black, except for myriad stars. hassan lay with his ear to the ground. rick held perfectly still and waited. finally hassan sat up. "close now," he whispered. rick wondered briefly if they shouldn't put up a fight, but he knew it would be useless. youssef had too many men. the camels appeared like wraiths from behind the dune, and rick blinked trying to see more clearly. there were three, and only one of them carried a rider. he waited tensely for the rest of the band to appear. the camels arrived and rick whispered urgently, "the rest must be behind. jump him and we'll grab the camels and make a run for it." hassan tensed. "yes. be ready." the camel rider came close, and lifted a hand in greeting. "_assalamo alaikum. fil khedma, ya sidi. ana gay men sidi moustafa._" rick was tensed to spring, to haul the man from his saddle, when hassan put a hand on his arm. "wait. he say greeting, he is at your service, and he come from mr. moustafa!" rick watched in unbelieving amazement as the driver forced his groaning camel to kneel, then immediately commanded the other two to kneel also. when the camel's protests had ceased, hassan spoke to him rapidly. the man answered at length. "he was with youssef," hassan said. "but he is also in the pay of kemel moustafa. last night he went to moustafa and told him about us. moustafa sent him to bring us back." rick hesitated. could they trust this man? but it was a silly question, because he knew he had no choice. anything was better than sitting in the desert and waiting. "ask if he has water, then we'll go with him." the man did, a full water bag. they drank sparingly, knowing the danger of too much water after deprivation. then the three mounted the camels. rick held onto the horn in front of him as the mount lurched protestingly to its feet, then they were going across the sands to the east at what seemed incredible speed. ahead of them, the first flush of real dawn was visible. * * * * * the sun was high before they came within sight of the first man-made objects in the desert. rick saw pyramids, but not those of giza. he called to hassan, who was riding his swaying mount like a veteran. "what pyramids are those, hassan?" "sakkarah," the dragoman replied. "we come back long way around." to the east, then the south, rick thought. he was by no means sure of what would be waiting, but at least he knew where he was. sakkarah, a "must" for tourists, bartouki had said. well, he was getting there, even though he had taken the hard way. on the road near sakkarah a car was waiting, and in it was kemel moustafa. the cameleer made the mounts kneel. rick and hassan got off, and the man with the camels hurried away without a word. the two walked up to the car. "thank you for rescuing us," rick said politely. moustafa had not spoken. now he tugged at his mustache and nodded. "whether it was worth while remains to be seen. according to my man, youssef did not get the cat. this is correct?" "yes. did you see my friend last night?" "i did. precisely at seven. he informed me that you were missing. then, sometime later, my man managed to leave youssef's gang and report in. i at once made plans for your rescue. now tell me. where is the cat?" rick was very, very tired of the egyptian cat. he thought grimly that when he returned home he and his sister would have a long talk about volunteering services for strangers. "the cat is under the back cushion of hassan's car," he said tiredly. "and the sooner you take it off my hands, the better." "hassan's car is at the hotel," moustafa said. "come. we will go there at once." rick and hassan climbed into the car and moustafa raced the motor. he meshed gears and spun his wheels as he got off to a fast start. he's certainly in a hurry to get that cat, rick thought. well, he was the legitimate receiver. only it was too bad to let the animal go without ever knowing what it contained. no matter, rick thought, as the desert road sped underneath. no matter now. in a few minutes it will be finished. chapter xvii ismail ben adhem rick awoke with the setting sun in his eyes. he yawned luxuriously and turned over to look at the clock, then sat upright in bed at the sight of scotty and a stranger. the stranger was young, with a friendly smile. he was relaxed as he sat in a comfortable chair, but it was the same kind of relaxation one sees in a panther or another of the great cats. rick knew, without even asking, that this lean, bronzed, good-looking egyptian was a police officer and that he probably was a very good one. he _looked_ like a hunter. "thought you were going to sleep till tomorrow," scotty said. "rick, this is inspector ismail ben adhem of the cairo police." the inspector held out a brown hand. rick sensed the strength in it, although the handshake was normal. "i'm glad you're here," the boy said frankly. "between youssef and kemel moustafa, we're sort of in a jam." the inspector smiled. "well see if we can get you out of it. suppose you call me ben, just to make things easy. now, scotty has given me a detailed report of your activities up to the time you left the project yesterday. suppose we pick up from there?" "okay. can i order breakfast first?" "of course. forgive my impatience. we can talk at leisure over coffee." rick placed the order, then launched into a recital of yesterday's events, including his night in the desert and rescue by kemel moustafa. he concluded, "we came back to the hotel. hassan opened the car, and the cat was gone. of course i had no idea what had happened to it. moustafa turned black with rage. he said i had a clear choice of getting the cat back and turning it over to him, or having something unpleasant happen. he'll be back at seven. he wasn't joking." "no," ben agreed. "i know this man, and he does not joke. what then?" "i sent hassan home to get some rest, and i came up to the room and called the project. scotty answered. he told me felix was safe, so i knew he had the cat, and he told me the police had been called in. i just fell into bed and went to sleep. that's it." "it's enough," the inspector said. "of course neither of you had any way of knowing what was going on. you had merely undertaken to do a favor for an acquaintance. i just wish some kind wind had whispered to you the idea of reporting to us after that first day in el mouski." "i guess we were wrong," rick admitted. "at first it didn't seem like a matter for the police. later, we just didn't think of it." "i understand. but it doesn't pay to be too independent in a strange land, i assure you. ask steve ames." the boys stared in amazement. steve ames was a close friend, and their contact in janig, one of the top american government security organizations. "how do you know steve?" rick asked in astonishment. "he and i went through the fbi academy together. we keep in touch. also, the international police organization, which is called interpol, keeps us up to date on developments. i know that your scientific group works closely with steve." so ismail ben adhem was an fbi graduate! rick looked at him with new respect. "i guess we should have reported to you," he said. "we just didn't know." "no matter. it will all work out, anyway. in fact, your delay in contacting us may even make things simpler." "how?" scotty asked. ben shrugged. "we will see. this cat of yours has many interesting possibilities." "do you know why the cat is important?" rick demanded. "i have an idea. but please do not press me for details. it is better for everything to go on normally while i do a little useful work. so, i suggest you two continue on as before, with only one difference. you will use a different taxi to travel back and forth to sahara wells." "but hassan is our dragoman," rick protested. "what's more, he's a friend. we can't switch now, after we engaged him for the duration of our stay." ben smiled warmly. "your loyalty to hassan does you credit. but don't worry. he will be taken care of. you and i will trade transportation. i will use hassan, and you will use my taxi." "i don't get it," scotty said. "it's simple. both of you are able to testify to criminal actions on the part of youssef. also, if this works out as i hope, you will have testimony to give on the actions of kemel moustafa. now, if you knew there was evidence against you, and you were completely ruthless, what would you do?" "remove the evidence," rick said slowly. his eyes met scotty's. "exactly. so, hassan stays with me, and your taxi driver will be one of my best officers. he will stay with you at all times. while you are in the hotel, another of my men will be your hall porter." "do you really think we're in any danger?" scotty asked. "don't ever doubt it, scotty. be on guard at all times." "it's because the cat is very important," rick stated. "and the cat is important because of something inside of it. you know what that something is." "an excellent deduction," ben agreed with a grin. "all but the last statement. i do not know what it is. i merely suspect. my evidence is circumstantial. i'll tell you this much, though. i know a great deal about certain interests of the moustafa brothers, and i was informed by interpol that there is an interesting gentleman of great wealth in san francisco who talks too much." rick thought over the statement. it didn't help at all. he couldn't see what a talkative man in california had to do with the egyptian cat. "that's not very informative," he objected. ben laughed. "i'm sure it isn't. but i'll make you a promise. before you leave egypt, we will perform a small operation on the cat and remove its appendix--or whatever else it may have inside." "we'll hold you to that," scotty told him. rick's breakfast arrived, and over _cafã© au lait_ and egyptian rolls ismail ben adhem questioned rick until he was sure he had extracted all the information the two boys had. it suddenly occurred to rick that he had asked no questions himself. "where's the cat?" he demanded. "at the project," scotty replied. "i was going to turn it over to ben, but he said to leave it there." "it might be uncomfortable at the station," ben added with a twinkle. "after all, it's a well-cared-for pet." rick grinned. "we've grown fond of it," he admitted. "second question: can't you just pick up youssef on a kidnapping charge?" "we could, if we knew where to find him. but youssef is a hard man to locate when he goes underground. we've been trying to get something on him for years, and we know him well. this time he's over-played his hand and we've got him. it's only a question of time." "how about moustafa?" rick asked. "is he guilty of anything?" the police officer finished his coffee and rose. "not yet," he said. "but he will be. now, stay together at all times. ride with the taxi driver who will be waiting for you in the hall. otherwise, go about your business as usual, and have a good time." scotty saw him to the door, then turned to rick. "moustafa isn't guilty of anything yet, but he will be. that's interesting." rick thought so, too. "isn't it pretty careless, leaving the cat at the project?" "seems so," scotty agreed. "but i think ben knows what he's doing." "i guess you're right," rick said soberly. after more coffee and a shower, he felt like himself again. there was work to do at the project, so the two boys picked up the police driver, who was keeping an eye on their door, and rode to the project. the scientists greeted rick happily. "we were pretty worried for a while," winston said, and the egyptians echoed him. "we don't usually treat tourists this way," farid said jokingly, but behind the smile rick sensed that the egyptian scientist was embarrassed by what had happened to a guest. "i got myself into it," rick pointed out. "if we had gone to the police about the egyptian cat that first day, there would have been no trouble." dr. kerama put a hand on his shoulder. "it is very kind of you to try to save our feelings. but we were so involved in this fascinating problem that we simply didn't pay enough attention. otherwise, we could have advised you to see the police." "how is it going?" rick asked. "very well," farid said. "we're exchanging reports constantly with the other radio telescopes and it's clear that we have something extraordinary. we're trying to agree on the precise location of this space object. the next step will be to examine the signals more closely to see if a pattern can be found or if they're simply random." "if you and scotty feel up to it," winston added, "we'd like you to duplicate the audio tapes for us. we want to send a set right away to green bank. they started audio recording, too, yesterday, but they don't have the hours when the object was in sight of our telescope but not theirs. they're duplicating the signals we didn't get after the object dropped below our horizon. that way we'll both have a complete record for analysis." "what is the space object?" rick asked. winston shook his head. "we don't know. it's too early even to speculate much. can you make the duplicates?" it was early evening. "we can get sandwiches at the mena house and work until we're finished," rick replied. "that will get us home before midnight. there can't be more than a few hours to record." "fine. you'll be alone, but since the inspector put a police guard on you, i'm sure it will be all right." farid had arranged the technical setup, using another unit borrowed from the government radio station for the purpose. all they would need to do was feed tape into the machines and watch the recording level. one of the egyptian technicians drove to the mena house and brought back sandwiches and cokes. the scientists departed, to have a quick dinner and then resume work at a different location where a computer was available to do the complicated mathematics required for analysis of the data. rick and scotty started work right away. the police driver sat in a chair and watched them. he spoke english, but wasn't much of a conversationalist. after a while the boys forgot he was there. listening to the space signal was strange. as the tape ran through, rick was certain his ear detected a kind of pattern in the sounds. there was a continuous hiss; that was normal hydrogen on the 21-centimeter wave length. then there were sharper hisses, as though some strange creature was trying to send a coded message through the noisy hydrogen background. "it's a message of some kind," rick stated. "i'll bet on it." "who sends messages from space?" scotty asked with a grin. "ghouls, ghosties, or long-legged beasties?" "don't laugh," rick said impatiently. "didn't you ever hear of project ozma?" scotty hadn't. "the wizard of ozma?" "the name comes from princess ozma of oz, i guess, but it was the first project to use the green bank telescope to try to locate intelligent signals from space. stuff exactly like this." "you're kidding!" "nope. on the level." scotty listened to the continuous signal, his face thoughtful. "maybe there is intelligence behind it. and maybe not. i don't get much of a pattern out of the sounds." "maybe the seven-eyed men of the planet glup don't have rhythm," rick began. "anyway ..." he never finished the sentence. the control-room door slammed open. arabs crashed through, bringing the police guard to his feet with a bound. he snatched a pistol from a shoulder holster and got off two shots before an answering shot caught him and spun him around with the impact. the police guard slid slowly to the floor! chapter xviii the fight at sahara wells the pistol dropped from the police driver's nerveless hand and scotty leaped. rick dropped to the floor as his pal picked up the pistol and rolled, shooting as he turned. his second shot caught an arab and slammed him back into the others who were trying to crowd in. rick looked frantically for a weapon. the only thing in sight was a heavy ceramic ash tray that the guard's fall had knocked to the floor. he grabbed it and threw, rising to one elbow. the ash tray caught an arab in the throat. someone shot, and chips flew from the cement floor next to rick's head. he rolled away. scotty aimed with care, as coolly as though he stood on the range back home. he squeezed the trigger and was rewarded by a choked yell from beyond the doorway. he fired again, and a burnoosed figure grabbed the doorframe for support. the arabs beyond the doorway had dived for cover, leaving the doorframe clear except for the most recent victim of scotty's shooting and the one rick had hit. he was lying on the floor with both hands clutched to his throat, gagging and gasping for air. a headdress was thrust around the frame and scotty squeezed off a quick shot. the hammer clicked harmlessly. he was out of ammunition! he threw the pistol and the head vanished. both boys got to their feet and crouched to rush any newcomers. they whirled at the tinkle of broken glass behind them. youssef stood in the window, a sten gun trained on them. rick looked at the deadly little submachine gun and gulped. he remembered what ben had said about removing the evidence. the thief said, "put both hands on top of your heads." the boys did so, with no hesitation. in spite of youssef's apparently casual manner, both knew he would not hesitate to shoot. he raised his voice and shouted in arabic. the boys stiffened as footsteps sounded behind them and gun muzzles were thrust into their backs. youssef vanished from the window and reappeared in a moment through the door. "you're a difficult young man," he told rick. "but the time for being difficult is over. i want the cat, now." "i left it in hassan's car," rick said, with pretended hopelessness. youssef spoke in arabic. the pressure of the gun muzzle left rick's back. he felt a cord being slipped around his forehead, a cord with hard knots that fell across his temples. "what you feel is a strangler's cord," the thief said grimly. "don't be a fool. the cat means nothing to you; you were merely a messenger boy. give me the cat and you will be left alone." "not until the evidence is destroyed," rick thought. "not until we're dead." "it's in the car," he repeated. youssef lost his composure. he snapped an order in arabic and the cord tightened. rick gritted his teeth. next to him, scotty bent forward. "don't try it," the thief grated. "i only need one of you." his black eyes bored into rick's. "one of my men watched you and moustafa search hassan's car this morning. the cat was not there. where is it?" rick started to shout that he didn't know, when a burst of shooting accompanied by wild yells broke out outside. youssef spoke quickly in arabic, then turned to the boys. "sit down in those chairs. move, and you die. i will deal with you when i have found out what this is all about." the shooting gained in volume and the yells increased. the boys took the seats and stared at the big sudanese, who was covering them with the sten gun. the strangler's cord was draped carelessly about his neck. "that's a real gun fight outside," scotty whispered. rick nodded. he could detect several guns of different calibers, and the chatter of sten guns was distinctive. what was going on? the shooting lessened, then stopped altogether. the shouting increased. the big sudanese kept glancing over his shoulder at the doorway, as though fearful of what he might see, but he always glanced back too quickly for the boys to act. "watch it," scotty said from the corner of his mouth. rick casually got his feet under him and tensed. scotty's eyes opened wide and he choked, "inspector!" the sudanese whirled, sten gun ready, and the boys left their chairs in a bound. rick dove for the thief's knees while scotty smashed straight into him like a battering ram. the big man toppled over backward, his blazing sten gun chipping plaster from the ceiling. rick let go of his grip on the knees and clawed for the man's throat. scotty concentrated on the sten gun, grabbing the hot barrel and bending backward. the big sudanese heaved, and rick felt as though he was a terrier hanging to a wild bull. the man was incredibly strong. the boy grabbed his throat in one hand and fended off crushing blows with the other. he was concentrating so hard on holding his grip that a newcomer who ran into the control room had to yell. "get up, i said. all of you!" a heavy foot crashed down on the sten gun and held it. rick looked up, dazed with effort, into the cold face of kemel moustafa. third brother had a luger automatic, and he looked ready to use it. the boys rolled away and got to their feet. the sudanese got to his knees and started to get up. moustafa struck with the luger and the man collapsed. the pistol muzzle pointed at rick. "you double-crossed me," moustafa grated. "you were supposed to give me the cat an hour ago at the hotel. fortunately, i had one of my men follow youssef, because i suspected he would find the cat sooner or later. give it to me." "your men must have won the fight," rick ventured. "they did. conversation will not help. i have thought about this, and i am certain youssef did not get the cat. his presence here confirms it. also, i believe that you thought it was in the car until we searched. if youssef did not take it, your own friend did. you would not leave it in the hotel, so it must be here. either you give it to me freely, or i will shoot you and take my chances on finding it." rick hesitated. "make up your mind!" moustafa snapped. the pistol steadied on a line with rick's head. "give it to him," scotty said. "he means it." there were shots from outside again. moustafa blazed, "hurry! youssef's men must be loose. i count three and shoot! one, two...." "hold it," rick said hurriedly. "it's under the amplifier." he walked to the amplifier and bent, fumbling with the door latch. if he could shield his motions, he could grab the cat, turn, and throw. he might be lucky ... "just hand him the cat," scotty said quickly. rick seethed inside, but he knew scotty was right. the egyptian cat wasn't worth his life, no matter what it contained. he opened the door and took the cat out. then he turned slowly and held it out to moustafa. "you're being wise," moustafa said. his eyes gleamed. he reached for the cat. rick handed it to him. "drop!" a voice yelled. rick and scotty dove to the floor on the instant. moustafa whirled, gun lifted to shoot, and saw no one. "the building is surrounded by police officers," the voice said. "just drop your gun." the voice came from outside the doorway, and it belonged to ismail ben adhem. moustafa yelled desperately, "don't try anything, or i shoot the americans!" he faced the empty doorway, ready. ben's voice said, "if you will turn slowly, you will see a shotgun barrel pointed at you through the window. if you turn rapidly, it fires. and, as you turn, another shotgun will come through the doorway to cover you. you're all done, kemel. better drop it. i want you alive." third brother turned, slowly and carefully. rick looked up and saw the shotgun barrel, as ben had promised. he saw ben step through the doorway, a riot gun in his hands. moustafa's luger dropped to the floor. chapter xix the cat's secret the tape machines ran unnoticed, except for an occasional glance from rick and scotty. all through the fight the signals had continued, with no one paying any attention. rick hoped that if they came from intelligent beings, they were of a kind that didn't get involved in gang fights. next to him, bandages around one thigh, youssef sat, his hands handcuffed together in his lap. moustafa, unharmed but helpless, was handcuffed in another chair. from outside, the wail of ambulances announced that the wounded were being carried off, the police driver among them. he had been knocked out by a chest shot, but ben assured the boys there were superb surgeons in cairo who would take good care of him. the inspector sat on a chair facing the others, the egyptian cat in his hand. "now that things are quiet again," he said, "i think we might talk a little. i promised our two american guests that they would find out the secret of this little beast, and now is as good a time as any." "i can get a saw to open it with," rick offered eagerly. ben grinned. "patience, rick. first we must paint a background, so that we may see the whole picture. where shall we begin? with moustafa?" kemel moustafa maintained a sullen silence. "no co-operation? then i shall begin. boys, i regret to inform you that mr. kemel moustafa is a member of a conspiracy to overthrow the united arab republic government." rick and scotty turned to look at the mustached man. he sat impassively. "his brothers also are in this conspiracy. he told you they were in beirut, but he was not truthful. they are in jail, here in cairo, awaiting trial. we picked up ali the day before you arrived. we did not get fuad until an hour before you visited him. the local people were nervous over the arrest. many in that neighborhood support the moustafas." kemel moustafa spoke. "i'm not in it. you can't prove that i am." ben nodded. "proof may be difficult. that is why you were allowed to remain at large while we collected your brothers. but, meanwhile, we have you on a charge of armed robbery, since you used a pistol to get the cat from our american friends a few minutes ago." he turned to the boys. "talk of overthrowing a government probably sounds strange to you. it has been many years since the american government was in any danger of revolt." "we don't understand some of the foreign revolutions," rick agreed. "but i suppose when a group isn't satisfied, it's apt to plot a revolution if there seems to be a chance of success." "that's right," ben agreed. "our country is much older than yours, historically, but actually it's much younger. the republic is pretty new. some of our dissatisfied citizens still think it's more efficient to make changes with bullets instead of ballots." scotty asked, "why do they want to make changes? what kind of changes?" the inspector grinned. "many kinds. we have groups that think the monarchy ought to be restored. we have others who think our foreign policy is too neutral, or that it isn't neutral enough. and we also have people who don't like our currency controls because they prevent tremendous profits from speculation. there are other groups, too. all are minorities and the only way they can see to make rapid changes is to overthrow the government and set up their own." "then you have revolutionaries plotting all over the place!" rick exclaimed. "it's not quite that bad. most groups have little support, and only one or two have any funds. it takes money for revolution, you know." rick could see that revolutions cost plenty, and he began to see the importance of the egyptian cat. in the little plastic statue, in some form, were the finances of the revolt! "the money for the moustafa revolution was to come from america," ben continued. "bartouki needed a messenger, so he waited until one came along. that was you." rick protested, "but why should he trust his finances to a stranger? there must have been better ways of getting the money here!" the officer shook his head. "it is not as easy as you think. we know who these revolutionaries are. we keep an eye on their comings and goings. they do not get past our borders without a thorough customs inspection. now, ask yourself--who can get past customs with no difficulty? officials of governments, scientific groups who come at our invitation, and tourists." "why didn't he use someone disguised as a tourist?" scotty asked. "that probably would have been his method, except that you stumbled into things and the chance was too good to miss. also, you did not declare the cat on your customs statement. we would have been interested in an egyptian cat coming the wrong way!" "i didn't know i was supposed to declare it," rick said. "it just never occurred to me." ben glared. "technically, you have broken our laws." he relented and grinned. "but if you will promise to import no more egyptian cats...." "i promise, swear, and affirm," rick said hastily. "good. to continue. we took ali moustafa into custody, but not before a phone call reached him from new york. his chief clerk listened to this call and sold the information to youssef. the clerk also agreed, for a share of the profits, to pretend to be ali, and he enlisted the help of the other clerks. we know this from the clerk. he talked freely, in the hope of leniency." ben turned to youssef. "do you know what is in the cat?" the thief shook his head. "only that it is of great value. i bought the clerk's information and help because i knew it was the moustafas who stole the necklace from the museum. i believe the necklace is in the cat." rick stared. the kefren necklace, worth a quarter of a million! great ghostly pyramids! this was big business! "the necklace was smuggled out of the country," ben agreed. "we are certain of that. but i do not believe it is in the cat." "open it," rick begged. the inspector held up his hand. "presently. aren't you enjoying the suspense?" "it's killing us," scotty wailed. "ah, the impatience of the young!" ismail ben adhem obviously was having a good time. "well, the pieces are nearly tied up." "good," rick applauded. ben chuckled. "on the same day that kerama invited you to come, i had a call from the interpol clearinghouse in paris, a relay from the san francisco police. a wealthy collector of early egyptian objects in san francisco had been bragging that he had just purchased a genuine necklace that had belonged to one of the early pharaohs. we requested the americans to investigate." that explained the californian who talked too much, rick thought. he had known the purchase was illegal, but, like many collectors, could not resist letting a few friends in on his secret--and the secret had leaked to the police. "this collector had paid for the necklace with a certified check, which was cashed by an american accomplice." ben paused for effect. "the amount was two hundred thousand dollars cash." he got his effect. all four of his listeners gasped in amazement. "even moustafa didn't know the exact amount," rick thought. "the money was in thousand-dollar bills. i have the serial numbers." rick spoke up. "but, ben, numbered bills are like a flag! no one can spend them without getting caught." "that is true, rick, when something illegal is involved. had the collector kept his mouth shut, no one would have known any illegality was involved in the transaction." "but you can't use american money in cairo," scotty objected. "it has to be changed." "right, scotty. the problem was this: the revolutionaries could not convert their dollars to egyptian pounds in america. it would have attracted too much attention, because only a few banks and finance houses can handle such amounts, and then only in co-operation with the government. their best bet was to get the dollars into the arab countries. we can watch international traffic, but local traffic among the arab nations is hard to control. they would have sent the dollars to another country to be changed." "an arab country?" rick asked. "probably. the borders between the republic and its neighbors are desert, impossible to patrol. the dollars could have been sent, then gradually converted into egyptian currency. dollars sell readily in this part of the world, and sometimes not too many questions are asked." "i get the picture," rick stated. "the moustafas stole the necklace, and smuggled it to america. bartouki sold it to the collector, through an american helper. then he had the money sealed in the cat. he handed it to me, because my sister gave him an opening and i fell into it. meanwhile, you put ali in jail, then fuad. youssef got into the act through the clerk. so then we had kemel moustafa and youssef on our trail. why didn't you put kemel in jail, too? and how about bartouki?" "we had no evidence that would stand up in court against kemel, although we were convinced he was in the act with his brothers. that's why i waited until he tried to take the cat by force." rick exploded, "you used us and the cat for bait!" "it worked," ben pointed out mildly. "we got both youssef and moustafa, although the trap was only for kemel. and you were never in any real danger, except for a stray bullet. i've been in the unfinished barracks with my men since noontime. the senior scientists knew it. that's why they were willing to leave you alone. two of my men mingled with youssef's gang as soon as they arrived, and weren't detected. any sign of real danger to you and they'd have bailed you out fast. but we were holding off, because i had a radio message that kemel was on his way with a gang of his own." "you certainly had things taped," scotty said admiringly. "i guess we ought to be mad. but you'd have an equal right to get mad because we tried to go it alone." "we'll call it square," ben agreed. "about bartouki. we needed the evidence of the cat, and a statement from you that he had handed it to you. that was the only sure way of tying him in. tonight we'll send a message via interpol to the new york police." so far, everything had been circumstantial evidence. rick wanted to see if their guesses were correct. "open the cat," he begged. "get the saw," ben said. rick jumped to his feet. there was a toolbox in the closet. he brought it to the inspector. ben handed the cat to him. "saw away." scotty held the cat firmly on a chair while rick wielded the saw. plastic sawdust flew from under the blade. rick felt the blade hit metal and stopped. "hit something!" he said excitedly. "metal, but soft. like lead." scotty groaned. "do you suppose bartouki was telling the truth?" "we'll soon know." rick moved the saw blade to a different angle and began cutting around the cat, changing angles each time he hit the material on the inside. before long, the egyptian cat had a cut around its middle and rick put the saw away. there were a hammer and screw driver in the toolbox. he inserted the tip of the screw driver into the saw cut and tapped the handle with the hammer. the cat split open. scotty let out a yell of triumph. in the bottom half was a square of lead, and it was clearly a box, not a solid lump. "hurry!" rick pleaded. scotty took the screw driver and pried. the lead box yielded reluctantly. there wasn't a sound in the control room except for the impulses from the tape recorder, which ran on unnoticed. scotty pried gingerly, and the lead box came loose and dropped to the floor. rick scooped it up and turned it in his hands, looking for the opening. he found only a thin seam of solder around one flat side. "have to cut it open," rick said. using his jackknife, he scored the bead of solder. it cut easily. he scored it again, deeper, and felt the knife blade penetrate. he turned the box and did the same thing to both ends. face flushed with excitement, he took the screw driver, thrust it under the lid, and bent it upward. the box opened. it contained a solid wad of bills. rick touched the top one, still a little unbelieving. the figure on it was 1000! he turned the box over and tapped it. the bills dropped out. he didn't doubt there were two hundred of them. two hundred thousand dollars! rick looked at the expressions on the faces around him. scotty was standing with openmouthed excitement. youssef was leaning forward, feasting on the wealth with greedy eyes. moustafa was slumped in resignation. and ismail ben adhem had the look of the cat that swallowed the cream. "now," rick said triumphantly, "now we know why the cat was important!" chapter xx the signal vanishes rick studied the sanborn tracing. he could see where the pulsed signals gradually disappeared into a much stronger, steady 21-centimeter signal. "we lost it at 4:02 yesterday," winston said. "it hasn't reappeared. apparently the signal source moved into, or behind, a globular cluster." rick's brows knit. "that's more evidence that it was moving contrary to normal direction?" "it is," dr. kerama agreed. "what's more, the calculated velocity was simply incredible. the only velocities we know of that approximate it are those of galaxies at the very limit of our instruments." rick said what was on his mind. "it was a spaceship. what else would travel across normal star directions giving out signals?" he grinned sheepishly. it wasn't strictly proper to blurt out his own theories. "the possibility has occurred to us," kerama said slowly. "it is certainly the most appealing explanation, and it is natural that it should come to your mind, rick. but it is not the only possible solution." winston agreed. "there are others that are difficult to explain, unless you have a good background in astrophysics, rick." scotty said, "i'm sure you have lots of theories, but honestly--what do you really think?" the scientist glanced at his egyptian colleagues. farid urged, "tell him what we talked about last night. it may not be subject to any real proof, but i think the boys have a right to know what we've concluded." "all right," winston nodded. "to put it as briefly as possible, we agree that the most likely explanation is that we intercepted intelligent signals, sent out for some reason by some beings we can't even imagine. for one thing, the space object is so small that we can't even give it a dimension. neither can the other telescopes. mount palomar can see nothing." "a spaceship," rick said soberly. the implications of it were tremendous! "it's as good a name as any. and now, boys, let's start folding up our part of the operation. we have reservations on tomorrow's flight. that will put us into new york just about suppertime." "we hate to leave," scotty told the egyptian scientists. "unfortunately, thanks to that egyptian cat, we didn't get to see much of cairo." "at least i saw a piece of the sahara desert," rick said with a grin. "anyway, let's move. i have some shopping to do for my folks, and for jan miller, and especially barby." "going to take her a bouquet of egyptian poison ivy?" winston asked with a smile. "nope. i'm going to buy her some nice things, but i'm also going to take her the remains of the egyptian cat. just as a reminder." he turned to glance around the control room before leaving. the plaster on the ceiling would need repairing where the sten gun had chipped it down to the concrete roof slab, but there was little real damage to show the effect of last night's fight. even the window broken by youssef had been repaired. how simple it all had been--once ismail ben adhem had taken over. rick knew why he and scotty had failed to solve the mystery. there was too much information they did not have, such as the disposal of the kefren necklace and knowing that the moustafas were the prime movers in a revolution. farid and kerama had not been surprised. "there are some who do not like the controls on trade and exchange that our government had to impose," farid explained. "mostly, they are people who had things pretty much their own way before the republic was formed. they used to get special treatment from government officials who were in their pay, and they grew rich. now, that's impossible. so they plot revolution to bring the bad old days back again--bad old days for most egyptians, that is. the moustafas and bartouki used to be pretty powerful. i suppose they wanted that power back." dr. kerama added, "this is probably not the last try at revolution the police will have to stop. but our country grows more stable all the time, and the would-be revolutionaries grow older and perhaps wiser." "time goes on," rick agreed. "things change." he thought of kemel moustafa the revolutionary, the only one of the three brothers they had met--and he thought of hassan's saying. he added, "the little jackal barks, but the caravan passes." hakim farid laughed outright. "we'll make a good egyptian of you yet, rick." * * * * * the time along the greenwich meridian, from which all world times are measured, was 9:30 p.m. at spindrift island, it was 4:30 in the late afternoon. barby brant sat with her close friend, jan miller, before the roaring fire in the library. "i'll bet rick and scotty are having a marvelous time," barby said. there was no envy in the statement. she always protested volubly at being left behind, but that was more a matter of principle than anything else. once the boys had gone, she always simmered down enough to be glad they could go, even if she could not. jan, a slim, attractive dark-haired girl, said, "i'll bet they're glad you suggested that rick deliver the egyptian cat, too. it was an introduction to a real merchant, right in the bazaar." barby smiled. "they probably made a lot of new friends from just that one thing!" it was 5:30 in the afternoon on a tiny island off the coast of venezuela. two elderly men looked up from their inspection of a hot spring. the smaller of the two shrugged. he spoke in spanish. "i will keep watch. if new signs develop, i know where to go for help. it is the spindrift scientific foundation. if anyone can help us, that group can. if they can't--well, we are doomed." in cairo, it was 11:30. rick brant hauled himself to the top of the great pyramid of khufu. scotty and hassan joined him. the view was magnificent. cairo sparkled like a million jewels, and in places they could see the silver ribbon of the nile. rick turned and looked at the radio telescope at sahara wells, its great parabolic reflector gleaming in the brilliant moonlight. he was content. as a last adventure, and with the permission of winston, the three had decided to climb the pyramid by moonlight. now the mysteries of the egyptian cat and the strange signal from space were behind them. in eleven hours they would be air-borne, and tomorrow night they would sleep at home. hassan spoke. "i sorry to see you go. you come back, maybe?" "someday," scotty said. rick added, "when we show my sister that picture of you with the fancy clothes and that scimitar you borrowed, we'll have to bring her to see you in person. she won't believe her eyes." hassan chuckled softly. "tell her i will be her bodyguard, to protect her from youssef, if he ever gets free from jail. i will even protect her from our so terrible egyptian cats!" the three sat down on the rough stone at the top of the pyramid. once the great monument had risen to a sharply pointed capstone, but the blocks had been removed and only a tall wooden pole showed how high the pyramid had once reached. rick looked up at the stars and traced the outlines of the familiar constellations, orion, the twins, taurus, the big dog, and the little dog. out there, far beyond those constellations, a spaceship had once passed, sending unknown signals to an unknown destination, eventually to be intercepted here, within sight of the pyramids. "i wonder what it was," he mused aloud. scotty needed no explanation. "does it matter, if it was some kind of intelligence?" rick shook his head. "not really. it was nearly five thousand light years away, so it took five thousand years to reach us. so when the signals were first sent, this pyramid hadn't even been built. egypt hadn't been united." scotty added, "and in the upper nile kingdom, people were worshiping bubaste...." "... and egyptian cats," rick finished. the boy glanced up at the stars again and saw the tight cluster of the pleiades. across the world, the constellation was just coming into view of anyone standing on top of the mountain known as el viejo, the old one. the slow stirring in the earth deep under el viejo would take a few months to grow, but already events taking form would plunge rick, scotty, and the spindrift scientists into the midst of mob violence, armed revolt, and one of the most daring scientific feats of all time, a story to be told in the adventure of the flaming mountain. _the_ rick brant science-adventure _stories_ by john blaine the rocket's shadow the lost city sea gold 100 fathoms under the whispering box mystery the phantom shark smugglers' reef the caves of fear stairway to danger the golden skull the wailing octopus the electronic mind reader the scarlet lake mystery the pirates of shan the blue ghost mystery the egyptian cat mystery sir william herschel his life and works [illustration: sir william herschel] sir william herschel his life and works by edward s. holden united states naval observatory, washington [illustration: coelis exploratis] new york charles scribner's sons 743 and 745 broadway 1881 copyright, 1880, by charles scribner's sons. press of j. j. little & co., nos. 10 to 20 astor place, new york. please see the end of the text for transcriber's notes preface. in the following account of the life and works of sir william herschel, i have been obliged to depend strictly upon data already in print--the _memoir_ of his sister, his own scientific writings and the memoirs and diaries of his cotemporaries. the review of his published works will, i trust, be of use. it is based upon a careful study of all his papers in the _philosophical transactions_ and elsewhere. a life of herschel which shall be satisfactory in every particular can only be written after a full examination of the materials which are preserved at the family seat in england; but as two generations have passed since his death, and as no biography yet exists which approaches to completeness, no apology seems to me to be needed for a conscientious attempt to make the best use of the scanty material which we do possess. this study will, i trust, serve to exhibit so much of his life as belongs to the whole public. his private life belongs to his family, until the time is come to let the world know more of the greatest of practical astronomers and of the inner life of one of its most profound philosophers,--of a great and ardent mind, whose achievements are and will remain the glory of england. contents. page chapter i. early years; 1738-1772, 1 chapter ii. life in bath; 1772-1782, 33 chapter iii. life at datchet, clay hall, and slough; 1782-1822, 68 chapter iv. review of the scientific labors of herschel, 118 bibliography, 215 index of names, 235 life and works of william herschel. chapter i. early years; 1738-1772. of the great modern philosophers, that one of whom least is known, is william herschel. we may appropriate the words which escaped him when the barren region of the sky near the body of _scorpio_ was passing slowly through the field of his great reflector, during one of his sweeps, to express our own sense of absence of light and knowledge: _hier ist wahrhaftig ein loch im himmel._ herschel prepared, about the year 1818, a biographical memorandum, which his sister carolina placed among his papers. this has never been made public. the only thoroughly authentic sources of information in possession of the world, are a letter written by herschel himself, in answer to a pressing request for a sketch of his life, and the _memoir and correspondence of caroline herschel_ (london, 1876), a precious memorial not only of his life, but of one which otherwise would have remained almost unknown, and one, too, which the world could ill afford to lose. the latter, which has been ably edited by mrs. mary cornwallis herschel,[1] is the only source of knowledge in regard to the early years of the great astronomer, and together with the all too scanty materials to be gained from a diligent search through the biography of the time, affords the data for those personal details of his life, habits, and character, which seem to complete the distinct, though partial conception of him which the student of his philosophical writings acquires. the letter referred to was published in the göttingen magazine of science and literature, iii., 4, shortly after the name of herschel had become familiar to every ear through his discovery of _uranus_, but while the circumstances of the discovery, and the condition of the amateur who made it, were still entirely unknown. the editor (lichtenberg) says: "herr herschel was good enough to send me, some time since, through herr magellan, copies of his dissertations on double stars, on the parallax of the fixed stars, and on a new micrometer. in the letter which conveyed to him my thanks for his gift, i requested him to note down a few facts in regard to his life, for publication in this magazine, since various accounts, more or less incorrect, had appeared in several journals. in answer, i received a very obliging letter from him and what follows is that portion of it relating to my request, which was sent me with full permission to make it public." "datchet, near windsor, _nov. 15, 1783._ "i was born in hanover, november, 1738. my father, who was a musician, destined me to the same profession, hence i was instructed betimes in his art. that i might acquire a perfect knowledge of the theory as well as of the practice of music, i was set at an early age to study mathematics in all its branches--algebra, conic sections, infinitesimal analysis, and the rest. "the insatiable desire for knowledge thus awakened resulted next in a course of languages; i learned french, english, and latin, and steadfastly resolved henceforth to devote myself wholly to those sciences from the pursuit of which i alone looked for all my future happiness and enjoyment. i have never been either necessitated or disposed to alter this resolve. my father, whose means were limited, and who consequently could not be as liberal to his children as he would have desired, was compelled to dispose of them in one way or another at an early age; consequently in my fifteenth year i enlisted in military service, only remaining in the army, however, until i reached my nineteenth year, when i resigned and went over to england. "my familiarity with the organ, which i had carefully mastered previously, soon procured for me the position of organist in yorkshire, which i finally exchanged for a similar situation at bath in 1766, and while here the peculiar circumstances of my post, as agreeable as it was lucrative, made it possible for me to occupy myself once more with my studies, especially with mathematics. when, in the course of time, i took up astronomy, i determined to accept nothing on faith, but to see with my own eyes everything which others had seen before me. having already some knowledge of the science of optics, i resolved to manufacture my own telescopes, and after many continuous, determined trials, i finally succeeded in completing a so-called newtonian instrument, seven feet in length. from this i advanced to one of ten feet, and at last to one of twenty, for i had fully made up my mind to carry on the improvement of my telescopes as far as it could possibly be done. when i had carefully and thoroughly perfected the great instrument in all its parts, i made systematic use of it in my observations of the heavens, first forming a determination never to pass by any, the smallest, portion of them without due investigation. this habit, persisted in, led to the discovery of the new planet (_georgium sidus_). this was by no means the result of chance, but a simple consequence of the position of the planet on that particular evening, since it occupied precisely that spot in the heavens which came in the order of the minute observations that i had previously mapped out for myself. had i not seen it just when i did, i must inevitably have come upon it soon after, since my telescope was so perfect that i was able to distinguish it from a fixed star in the first minute of observation. "now to bring this sketch to a close. as the king had expressed a desire to see my telescope, i took it by his command to greenwich, where it was compared with the instruments of my excellent friend, dr. maskelyne, not only by himself, but by other experts, who pronounced it as their opinion that my instrument was superior to all the rest. thereupon the king ordered that the instrument be brought to windsor, and since it there met with marked approval, his majesty graciously awarded me a yearly pension, that i might be enabled to relinquish my profession of music, and devote my whole time to astronomy and the improvement of the telescope. gratitude, as well as other considerations specified by me in a paper presented to the royal society, of which i am a member, has induced me to call the new planet _georgium sidus_. "'georgium sidus.--jam nunc assuesce vocari.'--(_virgil._) and i hope it will retain the name." we know but little of the family of herschel. the name is undoubtedly jewish, and is found in poland, germany, and england. we learn that the ancestors of the present branch left moravia about the beginning of the xviith century, on account of their change of religion to protestantism. they became possessors of land in saxony. hans herschel, the great-grandfather of william, was a brewer in pirna (a small town near dresden). of the two sons of hans, one, abraham (born in 1651, died 1718), was employed in the royal gardens at dresden, and seems to have been a man of taste and skill in his calling. of his eldest son, eusebius, there appears to be little trace in the records of the family. the second son, benjamin, died in infancy; the third, isaac, was born in 1707 (jan. 14), and was thus an orphan at eleven years of age. isaac was the father of the great astronomer. he appears to have early had a passionate fondness for music, and this, added to a distaste for his father's calling, determined his career. he was taught music by an oboe-player in the royal band, and he also learned the violin. at the age of twenty-one he studied music for a year under the cappelmeister pabrich, at potsdam, and in august, 1731, he became oboist in the band of the guards, at hanover. in august, 1732, he married anna ilse moritzen. she appears to have been a careful and busy wife and mother, possessed of no special faculties which would lead us to attribute to her care any great part of the abilities of her son. she could not herself write the letters which she sent to her husband during his absences with his regiment. it was her firm belief that the separations and some of the sorrows of the family came from too much learning; and while she could not hinder the education of the sons of the family, she prevented their sisters from learning french and dancing. it is but just to say that the useful accomplishments of cooking, sewing, and the care of a household, were thoroughly taught by her to her two daughters. the father, isaac, appears to have been of a different mould, and to him, no doubt, the chief intellectual characteristics of the family are due. his position obliged him to be often absent from hanover, with his regiment, but his hand appears to have been always present, smoothing over difficulties, and encouraging his sons to such learning and improvement as was to be had. his health was seriously injured by the exposures of the campaigns, and he was left, after the seven years' war, with a broken constitution. after his final return home, in 1760, his daughter gives this record of him- "copying music employed every vacant moment, even sometimes throughout half the night. . . . with my brother [dietrich]--now a little engaging creature of between four and five years old--he was very much pleased, and [on the first evening of his arrival at home] before he went to rest, the adempken (a little violin) was taken from the shelf and newly strung, and the daily lessons immediately commenced. . . . i do not recollect that he ever desired any other society than what he had opportunities of enjoying in many of the parties where he was introduced by his profession, though far from being of a morose disposition; he would frequently encourage my mother in keeping up a social intercourse among a few acquaintances, whilst his afternoon hours generally were taken up in giving lessons to some scholars at home, who gladly saved him the troublesome exertion of walking. . . . he also found great pleasure in seeing dietrich's improvement, who, young as he was, and of the most lively temper imaginable, was always ready to receive his lessons, leaving his little companions with the greatest cheerfulness to go to his father, who was so pleased with his performances that he made him play a solo on the adempken in rake's concert, being placed on a table before a crowded company, for which he was very much applauded and caressed, particularly by an english lady, who put a gold coin in his little pocket. "it was not long before my father had as many scholars as he could find time to attend. and when they assembled at my father's to make little concerts, i was frequently called to join the second violin in an overture, for my father found pleasure in giving me sometimes a lesson before the instruments were laid by, after practising with dietrich, for i never was missing at those hours, sitting in a corner with my knitting and listening all the while." here, as in all her writing, carolina is simple, true, direct to awkwardness, and unconsciously pathetic even in joy. the family of isaac and anna herschel consisted of ten children. six of these lived to adult age. they were: 1. sophia elizabeth; born 1733, married griesbach, a musician in the guard, by whom she had children. five of her sons were afterwards musicians at the court, in england, where they obtained places through the influence of william. 2. henry anton jacob; born 1734, november 20. 4. frederic william (the astronomer) born 1738, november 15. 6. john alexander; born 1745, november 13. 8. carolina lucretia; born 1750, march 16. 10. dietrich; born 1755, september 13. of this family group, the important figures to us are william, alexander, and carolina. jacob was organist at the garrison church of hanover in 1753, a member of the guards' band in 1755, and first violin in the hanover court orchestra in 1759. afterwards he joined his brother william in bath, but again returned to hanover. in 1771 he published in amsterdam his opus i., a set of six quartettes, and later, in london, he published two symphonies and six trios. he appears to have been a clever musician, and his letters to his younger brother william are full of discussion on points of musical composition, etc. he died in 1792. dietrich, the youngest brother, shared in the musical abilities of his family, and when only fifteen years old was so far advanced as to be able to supply his brother jacob's place in the court orchestra, and to give his lessons to private pupils. there is no one of the family, except the eldest daughter, whom we do not know to have possessed marked ability in music, and this taste descended truly for four generations. in the letters of chevalier bunsen,[2] he describes meeting, in 1847, the eldest granddaughter of william herschel, who, he says, "is a musical genius." three members of the family, william, alexander, and carolina, formed a group which was inseparable for many years, and while the progress of the lives of alexander and carolina was determined by the energy and efforts of william, these two lent him an aid without which his career would have been strangely different. it is necessary to understand a little better the early life of all three. the sons of the herschel family all attended the garrison school in hanover until they were about fourteen years old. they were taught the ordinary rudiments of knowledge--to read, to write, to cipher--and a knowledge of french and english was added. william especially distinguished himself in his studies, learning french very rapidly, and studying latin and arithmetic with his master out of hours. the household life seems to have been active, harmonious, and intelligent, especially during the presence of the father, who took a great delight in the rapid progress of all his sons in music, and who encouraged them with his companionship in their studies and in their reading on all intellectual subjects. from the _memoir_ of carolina, on which we must depend for our knowledge of this early life, we take the following paragraph: "my brothers were often introduced as solo performers and assistants in the orchestra of the court, and i remember that i was frequently prevented from going to sleep by the lively criticism on music on coming from a concert, or by conversations on philosophical subjects, which lasted frequently till morning, in which my father was a lively partaker and assistant of my brother william, by contriving self-made instruments. . . . often i would keep myself awake that i might listen to their animating remarks, for it made _me so happy_ to see _them so happy_. but generally their conversation would branch out on philosophical subjects, when my brother william and my father often argued with such warmth that my mother's interference became necessary, when the names leibnitz, newton, and euler sounded rather too loud for the repose of her little ones, who ought to be in school by seven in the morning. but it seems that on the brothers retiring to their own room, where they shared the same bed, my brother william had still a great deal to say; and frequently it happened that when he stopped for an assent or reply, he found his hearer was gone to sleep, and i suppose it was not till then that he bethought himself to do the same. "the recollection of these happy scenes confirms me in the belief, that had my brother william not then been interrupted in his philosophical pursuits, we should have had much earlier proofs of his inventive genius. my father was a great admirer of astronomy, and had some knowledge of that science; for i remember his taking me, on a clear frosty night, into the street, to make me acquainted with several of the most beautiful constellations, after we had been gazing at a comet which was then visible. and i well remember with what delight he used to assist my brother william in his various contrivances in the pursuit of his philosophical studies, among which was a neatly turned 4-inch globe, upon which the equator and ecliptic were engraved by my brother." the mechanical genius was not confined to william, for we read that alexander used often to "sit by us and amuse us and himself by making all sorts of things out of pasteboard, or contriving how to make a twelve-hour cuckoo clock go a week." this ability of alexander's was turned later to the best account when he became his brother william's right hand in the manufacture of reflectors, eye-pieces, and stands in england. his abilities were great, and a purpose which might otherwise have been lacking was supplied through the younger brother's ardor in all that he undertook. his musical talent was remarkable; he played "divinely" on the violoncello. he returned to hanover in 1816, where he lived in comfortable independence, through the never-failing generosity of his brother, until his death in 1821. a notice of him in a bristol paper says: "died, march 15, 1821, at hanover, alexander herschel, esqr., well known to the public of bath and bristol as a performer and elegant musician; and who for forty-seven years was the admiration of the frequenters of concerts and theatres of both those cities as principal violoncello. to the extraordinary merits of mr. herschel was united considerable acquirement in the superior branches of mechanics and philosophy, and his affinity to his brother, sir william herschel, was not less in science than in blood." we shall learn more of the sister, carolina, as time goes on. now in these early years she was a silent and persistent child, growing up with a feeling that she was uncared for and neglected, and lavishing all her childish affection, as she did all that of her womanly life, on her brother william. throughout her long life, "my brother" was william, "my nephew" _his_ son. the brothers jacob and william were, with their father, members of the band of the guards in 1755, when the regiment was ordered to england, and they were absent from hanover a year. william (then seventeen years old) went as oboist, and out of his scanty pay brought back to hanover, in 1756, only one memento of his stay--a copy of locke _on the human understanding_. he appears to have served with the guard during part of the campaign of 1757. his health was then delicate, and his parents "determined to remove him from the service--a step attended by no small difficulties."[3] this "removal" was hurriedly and safely effected, so hurriedly that the copy of locke was not put in the parcels sent after him to hamburg by his mother; "she, dear woman, knew no other wants than good linen and clothing." thus, at last, the young william herschel, the son of an oboe-player in the king's guard, is launched in life for himself, in the year 1757, at the age of nineteen. all his equipment is the "good linen and clothing," a knowledge of french, latin, and english, some skill in playing the violin, the organ, and the oboe, and an "uncommon precipitancy" in doing what there is to be done. a slender outfit truly; but we are not to overlook what he said of himself on another occasion. "i have, nevertheless, several resources in view, and do not despair of succeeding pretty well in the end." from 1757 to 1760--three years--we know nothing of his life. we can imagine what it was. his previous visit to england had given him a good knowledge of the language, and perhaps a few uninfluential acquaintances. on his return he would naturally seek these out, and, by means of his music, he could gain a livelihood. we first hear of him as charged with the organization of the music of a corps of the militia of durham, under the auspices of the earl of darlington. "la manière dont il remplit cette mission, le fit connaître avantageusement."[4] the nature of the service of these militia corps, which were then forming all over england, is well described in the autobiography of gibbon. every county-gentleman felt constrained to serve his country, and the regimental mess-rooms were filled with men of rank and fashion. in 1760 we hear of him again. he has attracted the notice of those about him. "about the year 1760, as miller[5] was dining at pontefract with the officers of the durham militia, one of them, knowing his love of music, told him they had a young german in their band as a performer on the hautboy, who had only been a few months in england, and yet spoke english almost as well as a native, and who was also an excellent performer on the violin; the officer added that if miller would come into another room, this german should entertain him with a solo. the invitation was gladly accepted, and miller heard a solo of giardini's executed in a manner that surprised him. he afterwards took an opportunity of having some private conversation with the young musician, and asked him whether he had engaged himself for any long period to the durham militia. the answer was, 'only from month to month.' 'leave them, then,' said the organist, 'and come and live with me. i am a single man, and think we shall be happy together; and, doubtless, your merit will soon entitle you to a more eligible situation.' the offer was accepted as frankly as it was made, and the reader may imagine with what satisfaction dr. miller must have remembered this act of generous feeling when he hears that this young german was herschel, the astronomer. 'my humble mansion,' says miller, 'consisted, at that time, but of two rooms. however, poor as i was, my cottage contained a library of well-chosen books; and it must appear singular that a foreigner who had been so short a time in england should understand even the peculiarities of the language so well as to fix upon swift for his favorite author.' "he took an early opportunity of introducing his new friend at mr. cropley's concerts; the first violin was resigned to him; 'and never,' says the organist, 'had i heard the concertos of corelli, geminiani, and avison, or the overtures of handel performed more chastely, or more according to the original intention of the composers, than by mr. herschel. i soon lost my companion; his fame was presently spread abroad; he had the offer of pupils, and was solicited to lead the public concerts both at wakefield and halifax. a new organ for the parish church of halifax was built about this time, and herschel was one of the seven candidates for the organist's place. they drew lots how they were to perform in succession. herschel drew the third, the second fell to dr. wainwright of manchester, whose finger was so rapid that old snetzler, the organ-builder, ran about the church exclaiming: '_te tevel! te tevel! he run over te keys like one cat; he will not give my piphes room for to shpeak._' 'during mr. wainwright's performance,' says miller, 'i was standing in the middle aisle with herschel. 'what chance have you,' said i, 'to follow this man?' he replied, 'i don't know; i am sure fingers will not do.' on which he ascended the organ loft, and produced from the organ so uncommon a fulness, such a volume of slow, solemn harmony, that i could by no means account for the effect. after this short _ex tempore_ effusion, he finished with the old hundredth psalm-tune, which he played better than his opponent. "'_ay, ay_,' cried old snetzler, '_tish is very goot, very goot indeet; i vil luf tish man, for he gives my piphes room for to shpeak._' having afterwards asked mr. herschel by what means, in the beginning of his performance, he produced so uncommon an effect, he replied, 'i told you fingers would not do!' and producing two pieces of lead from his waistcoat pocket, 'one of these,' said he, 'i placed on the lowest key of the organ, and the other upon the octave above; thus by accommodating the harmony, i produced the effect of four hands, instead of two.'"[6] the dates in this extract are not so well defined as might be wished. herschel had certainly been more than a few months in england at the time of his meeting with dr. miller, which was probably about 1760. the appointment as organist at halifax was in 1765, and the pupils and public concerts must have filled up the intervening five years. during a part of this time he lived in leeds, with the family of mr. bulman, whom he afterwards provided with a place as clerk to the octagon chapel, in his usual generous manner. all during his life he was placing some of the less fortunate and energetic members of his family. we cannot be too grateful to dr. miller, who, seeing his opportunity, used it. their frank friendship does honor to both. herschel's organ-playing, which no doubt had been begun when his brother was the organist of the garrison chapel at hanover, must have been perfected at this time, and it was through his organ-playing that he was able to leave the needy life in yorkshire. he was sure to have emerged sooner or later, but every year spared to him as a struggling musician was a year saved to astronomy. during all this period, a constant correspondence was maintained between the family at hanover and the absent son. many of william's letters were written in english, and addressed to his brother jacob, and treated of such subjects as the theory of music, in which he was already far advanced. his little sister was still faithful to the memory of her _dearest_ brother, and his father, whose health was steadily declining, became painfully eager for his return. in 1764 (april 2), he returned to hanover on a very brief visit. he was attached to england, he was prospering there, and he had no inclination towards returning to a life in hanover. his sister says: "of the joys and pleasures which all felt at this long-wished-for meeting with my--let me say my _dearest_--brother, but a small portion could fall to my share; for with my constant attendance at church and school, besides the time i was employed in doing the drudgery of the scullery, it was but seldom i could make one in the group when the family were assembled together. "in the first week, some of the orchestra were invited to a concert, at which some of my brother william's compositions, overtures, etc., and some of my eldest brother jacob's were performed, to the great delight of my dear father, who hoped and expected that they would be turned to some profit by publishing them, but there was no printer who bid high enough. "sunday, the 8th, was the--to me--eventful day of my confirmation, and i left home not a little proud and encouraged by my dear brother william's approbation of my appearance in my new gown." the engagement of herschel at halifax did not long continue. in 1766 he obtained an advantageous engagement as oboist at bath, and soon after the position of organist at the octagon chapel was offered to him and accepted. this was a great and important change. bath was then, as now, one of the most beautiful cities in england, and the resort of the fashion and rank of the kingdom, who came to take the waters. it is beautifully situated on both sides of the avon, and has many fine walks and public buildings. the aspect of the city is markedly cheerful and brilliant, owing to the nature of the white stone of which the principal houses are built, and to the exquisite amphitheatre of hills in which they lie. the society was then gay and polite, and herschel was at once thrown into a far more intelligent atmosphere than that he had just left in yorkshire. it was easy to get new books, to see new faces, to hear new things. the assembly rooms (built in 1771) were noted for their size and elegance; the theatre was the best out of london. his position as organist of the fashionable chapel placed him in the current. his charming and engaging manners made him friends. his talents brought him admirers and pupils, and pupils brought him money.[7] he began in 1766 a life of unceasing activity, which continued. in 1768 he published in london a symphony (in c) for two violins, viola, bass, two oboes, and two horns, and in the same year two military concertos for two oboes, two horns, two trumpets, and two bassoons.[8] he wrote pieces for the harp, glees, "catches," and other songs for the voice. one of these, the _echo catch_, was published and had even considerable vogue. a competent musical critic writes to me of this work: "the counterpoint is clear and flowing, and is managed with considerable taste and effect. it would be difficult to explain the great cleverness shown in the construction of the _catch_ without diagrams to illustrate the movements of the parts. it is certainly an ingenious bit of musical writing." when he left bath (in 1782), many of these musical writings were lost, in his great haste to take up his new profession. one, specially, his sister remembers to have written out for the printer, "but he could not find a moment to send it off, nor answer the printer's letters." this was a four-part song, "in thee i bear so dear a part." he wrote very many anthems, chants, and psalm-tunes for the excellent cathedral choir of the octagon chapel. unfortunately, most of this music is now not to be found. a notice of herschel's life which appeared in the _european magazine_ for 1785, january, gives a very lively picture of his life at this time, and it is especially valuable as showing how he appeared to his cotemporaries. "although mr. herschel loved music to an excess, and made a considerable progress in it, he yet determined with a sort of enthusiasm to devote every moment he could spare from business to the pursuit of knowledge, which he regarded as the sovereign good, and in which he resolved to place all his views of future happiness in life.". . . "his situation at the octagon chapel proved a very profitable one, as he soon fell into all the public business of the concerts, the rooms, the theatre, and the oratorios, besides many scholars and private concerts. this great run of business, instead of lessening his propensity to study, increased it, so that many times, after a fatiguing day of fourteen or sixteen hours spent in his vocation, he would retire at night with the greatest avidity to _unbend the mind_, if it may be so called, with a few propositions in maclaurin's _fluxions_, or other books of that sort." it was in these years that he mastered italian and made some progress in greek. "we may hazard a natural conjecture respecting the course of herschel's early studies. music conducted him to mathematics, or, in other words, impelled him to study smith's _harmonics_. now this robert smith was the author of _a complete system of optics_, a masterly work, which, notwithstanding the rapid growth of that branch of the science, is not yet wholly superseded. it seems to us not unlikely that herschel, studying the _harmonics_, conceived a reverence for the author, who was at that time still living, so that from the _philosophy of music_ he passed to the _optics_, a work on which smith's great reputation chiefly rested; and thus undesignedly prepared himself for the career on which he was shortly about to enter with so much glory."[9] there is no doubt that this conjecture is a true one. the _optics_ of dr. smith is one of the very few books quoted by herschel throughout his writings, and there is every evidence of his complete familiarity with its conclusions and methods; and this familiarity is of the kind which a student acquires with his early text-books. one other work he quotes in the same way, lalande's _astronomy_, and this too must have been deeply studied. during the years 1765-1772, while herschel was following his profession and his studies at bath, the family life at hanover went on in much the same way. in 1765 his father isaac had a stroke of paralysis, which ended his violin-playing forever, and forced him to depend entirely upon pupils and copying of music for a livelihood. he died on march 22, 1767, leaving behind him a good name, and living in the affectionate remembrance of his children and of all who knew him. carolina had now lost her best friend, and transferred to her brother william the affection she had before divided between him and her father. "my father wished to give me something like a polished education, but my mother was particularly determined that it should be a rough, but at the same time a useful one; and nothing farther she thought was necessary but to send me two or three months to a sempstress to be taught to make household linen. . . . my mother would not consent to my being taught french, and my brother dietrich was even denied a dancing-master, because she would not permit my learning along with him, though the entrance had been paid for us both; so all my father could do for me was to indulge me (and please himself) sometimes with a short lesson on the violin, when my mother was either in good humor or out of the way. though i have often felt myself exceedingly at a loss for the want of those few accomplishments of which i was thus, by an erroneous though well-meant opinion of my mother, deprived, i could not help thinking but that she had cause for wishing me not to know more than was necessary for being useful in the family; for it was her certain belief that my brother william would have returned to his country, and my eldest brother not have looked so high, if they had had a little less learning. * * * * * but sometimes i found it scarcely possible to get through with the work required, and felt very unhappy that no time at all was left for improving myself in music or fancy work, in which i had an opportunity of receiving some instruction from an ingenious young woman whose parents lived in the same house with us. but the time wanted for spending a few hours together could only be obtained by our meeting at daybreak, because by the time of the family's rising at seven, i was obliged to be at my daily business. though i had neither time nor means for producing anything immediately either for show or use, i was content with keeping samples of all possible patterns in needlework, beads, bugles, horse-hair, etc., for i could not help feeling troubled sometimes about my future destiny; yet i could not bear the idea of being turned into an abigail or housemaid, and thought that with the above and such like acquirements, with a little notion of music, i might obtain a place as governess in some family where the want of a knowledge of french would be no objection." a change was soon to come in her life too; her brother william wrote to propose that she should join him at bath- . . . "to make the trial, if, by his instruction, i might not become a useful singer for his winter concerts and oratorios; he advised my brother jacob to give me some lessons by way of beginning; but that if, after a trial of two years, we should not find it answer our expectation, he would bring me back again. this at first seemed to be agreeable to all parties, but by the time i had set my heart upon this change in my situation, jacob began to turn the whole scheme into ridicule, and, of course, he never heard the sound of my voice except in speaking, and yet i was left in the harassing uncertainty whether i was to go or not. i resolved at last to prepare, as far as lay in my power, for both cases, by taking, in the first place, every opportunity, when all were from home, to imitate, with a gag between my teeth, the solo parts of concertos, _shake and all_, such as i had heard them play on the violin; in consequence i had gained a tolerable execution before i knew how to sing. i next began to knit ruffles, which were intended for my brother william, in case i remained at home--else they were to be jacob's. for my mother and brother d. i knitted as many cotton stockings as would last two years at least." in august, 1772, her brother arrived at hanover, to take her back to england with him. the journey to london was made between august 16th and 26th, and soon after they went together to herschel's house, no. 7 new king's street, bath. footnotes: [1] wife of major john herschel, of the royal engineers, grandson of sir william. [2] page 127. [3] _memoir_ of carolina herschel, p. 10. sir george airy, astronomer royal, relates in the _academy_ that this "removal" was a desertion, as he was told by the duke of sussex that on the first visit of herschel to the king, after the discovery of the _georgium sidus_, the pardon of herschel was handed to him by the king himself, written out in due form. [4] fétis; _biographie universelle des musiciens_, tome v. (1839) p. 141. [5] dr. miller, a noted organist, and afterwards historian of doncaster. [6] _the doctor_; by robert southey, edition of 1848, p. 140. [7] he frequently gave thirty-five and thirty-eight lessons a week to pupils at this time. [8] according to fétis. a search for these in london has led me to the belief that fétis, who is usually very accurate, is here mistaken, and that these writings are by jacob herschel. [9] _foreign quarterly review_, volume 31. chapter ii. life in bath; 1772-1782. it was to a busy life in bath that herschel took his sister carolina, then twenty-two years old. she was a perfectly untried girl, of very small accomplishments and outwardly with but little to attract. the basis of her character was the possibility of an unchanging devotion to one object; for the best years of her life this object was the happiness and success of her brother william, whom she profoundly loved. her love was headstrong and full of a kind of obstinate pride, which refused to see anything but the view she had adopted. as long as her life continued to be with her dearest brother, all was well with her. she had a noble aim, and her heart was more than full. later on, this very singleness of character brought her other years of wretchedness. it is necessary to understand the almost spaniel-like allegiance she gave, in order to comprehend the value which her services were to herschel. she supplied him with an aid which was utterly loyal, entire, and devoted. her obedience was unquestioning, her reverence amounted almost to adoration. in their relation, he gave everything in the way of incentive and initiative, and she returned her entire effort loyally. at first her business was to gain a knowledge of the language, and to perfect herself in singing, so that she might become a soloist in the concerts and oratorios which he was constantly giving. in the beginning it was not easy. . . . "as the season for the arrival of visitors to the baths does not begin till october, my brother had leisure to try my capacity for becoming a useful singer for his concerts and oratorios, and being very well satisfied with my voice, i had two or three lessons every day, and the hours which were not spent at the harpsichord, were employed in putting me in the way of managing the family. . . . on the second morning, on meeting my brother at breakfast, he began immediately to give me a lesson in english and arithmetic, and showed me the way of booking and keeping accounts of cash received and laid out. . . . by way of relaxation we talked of astronomy and the bright constellations with which i had made acquaintance during the fine nights we spent on the postwagen travelling through holland. "my brother alexander, who had been some time in england, boarded and lodged with his elder brother, and, with myself, occupied the attic. the first floor, which was furnished in the newest and most handsome style, my brother kept for himself. the front room, containing the harpsichord, was always in order to receive his musical friends and scholars at little private concerts or rehearsals. . . . sundays i received a sum for the weekly expenses, of which my housekeeping book (written in english) showed the amount laid out, and my purse the remaining cash. one of the principal things required was to market, and about six weeks after coming to england i was sent alone among fishwomen, butchers, basket-women, etc., and i brought home whatever in my fright i could pick up. . . . my brother alex., who was now returned from his summer engagement, used to watch me at a distance, unknown to me, till he saw me safe on my way home. but all attempts to introduce any order in our little household proved vain, owing to the servant my brother then had. and what still further increased my difficulty was, that my brother's time was entirely taken up with business, so that i only saw him at meals. breakfast was at seven o'clock or before--much too early for me, who would rather have remained up all night than be obliged to rise at so early an hour. . . . "the three winter months passed on very heavily. i had to struggle against _heimwehe_ (home sickness) and low spirits, and to answer my sister's melancholy letters on the death of her husband, by which she became a widow with six children. i knew too little english to derive any consolation from the society of those who were about me, so that, dinner-time excepted, i was entirely left to myself." so the winter passed. "the time when i could hope to receive a little more of my brother's instruction and attention was now drawing near; for after easter, bath becomes very empty, only a few of his scholars, whose families were resident in the neighborhood, remaining. but i was greatly disappointed; for, in consequence of the harassing and fatiguing life he had led during the winter months, he used to retire to bed with a basin of milk or glass of water, and smith's _harmonics_ and _optics_, ferguson's _astronomy_, etc., and so went to sleep buried under his favorite authors; and his first thoughts on rising were how to obtain instruments for viewing those objects himself of which he had been reading. there being in one of the shops a two-and-a-half-foot gregorian telescope to be let, it was for some time taken in requisition, and served not only for viewing the heavens, but for making experiments on its construction. . . . it soon appeared that my brother was not contented with knowing what former observers had seen, for he began to contrive a telescope eighteen or twenty feet long (i believe after huyghens' description). . . . i was much hindered in my musical practice by my help being continually wanted in the execution of the various contrivances, and i had to amuse myself with making the tube of pasteboard for the glasses, which were to arrive from london, for at that time no optician had settled at bath. but when all was finished, no one besides my brother could get a glimpse of jupiter or saturn, for the great length of the tube would not allow it to be kept in a straight line. this difficulty, however, was soon removed by substituting tin tubes. . . . my brother wrote to inquire the price of a reflecting mirror for (i believe) a five or six foot telescope. the answer was, there were none of so large a size, but a person offered to make one at a price much above what my brother thought proper to give. . . . about this time he bought of a quaker, resident at bath, who had formerly made attempts at polishing mirrors, all his rubbish of patterns, tools, hones, polishers, unfinished mirrors, etc., but all for small gregorians, and none above two or three inches diameter. "but nothing serious could be attempted, for want of time, till the beginning of june, when some of my brother's scholars were leaving bath; and then, to my sorrow, i saw almost every room turned into a workshop. a cabinet-maker making a tube and stands of all descriptions in a handsomely furnished drawing-room; alex. putting up a huge turning machine (which he had brought in the autumn from bristol, where he used to spend the summer) in a bedroom, for turning patterns, grinding glasses, and turning eye-pieces, etc. at the same time music durst not lie entirely dormant during the summer, and my brother had frequent rehearsals at home, where miss farinelli, an italian singer, was met by several of the principal performers he had engaged for the winter concerts." finally, in 1774, he had made himself a gregorian telescope,[10] and had begun to view the heavens. he was then thirty-six years old. the writer in the _european magazine_ describes this period: "all this time he continued his astronomical observations, and nothing now seemed wanting to complete his felicity, but sufficient leisure to enjoy his telescopes, to which he was so much attached, that at the theatre he used frequently to run from the harpsichord to look at the stars, during the time between the acts." in an extract from his _journal no. 1_, now at the rooms of the royal society, may be seen a copy of his first observation of the nebula of _orion_, on march 4, 1774. this was made with his five-and-a-half-foot gregorian reflector. it was at this time (1775), between the acts of the theatre, that he made his first review of the heavens, with a newtonian telescope, of an aperture of four and a half inches and a magnifying power of 222 times. this telescope was one of the first made by himself. the review consisted of the examination of every star in the sky of the first, second, third, and fourth magnitudes, and of all planets visible. there are no records of these observations now extant, and they are noteworthy only as a preparation for more serious work. he was carrying out his resolve to see everything for himself. his assiduity may be judged of by the fact that between 1774 and 1781 herschel had observed a single object--the nebula of _orion_--no less than fourteen times. the success of his first telescopes incited him to new efforts. his house became a complete _atelier_, where everything that could tend to excellence in this manufacture was tried and re-tried a hundred different ways. when a difficulty arose, experiments were begun which continued till it was conquered. when a success was gained, it was prosecuted to the utmost. in 1775 the first seven-foot reflector was made, in 1777 a ten-foot was finished, in 1778 a "very good" ten-foot took its place. it must not be thought that the telescopes mentioned were the only ones completed. on the contrary, they were but the best ones selected out of many. in 1774 a new house had been engaged, which had "more room for workshops," and whose roof gave space for observing. the grass-plat near it was soon utilized to hold the stand of a twenty-foot telescope, which he had even then projected. his projects were unending, no success was final; his mind was at the height of activity; his whole effort was thrown into every undertaking. the mirrors for all these telescopes were made by hand. every portion of the grinding down to rough dimensions, the shaping to something near the correct form, the polishing till the accurately exact curves were obtained, all this must be done by hand. the machines for the purpose were not invented until 1788.[11] alexander and william worked together at this, but most of the work was done by the latter. the sister's part was to attend in the workshop and lend a hand wherever and whenever it was needed. . . . "my time was taken up with copying music and practising, besides attendance on my brother when polishing, since by way of keeping him alive i was constantly obliged to feed him by putting the victuals by bits into his mouth. this was once the case when, in order to finish a seven-foot mirror, he had not taken his hands from it for sixteen hours together. in general he was never unemployed at meals, but was always at those times contriving or making drawings of whatever came in his mind. generally i was obliged to read to him whilst he was at the turning-lathe, or polishing mirrors, _don quixote_, _arabian nights' entertainment_, the novels of sterne, fielding, etc.; serving tea and supper without interrupting the work with which he was engaged, . . . and sometimes lending a hand. i became, in time, as useful a member of the workshop as a boy might be to his master in the first year of his apprenticeship. . . . but as i was to take a part the next year in the oratorios, i had, for a whole twelvemonth, two lessons per week from miss fleming, the celebrated dancing-mistress, to drill me for a gentlewoman (god knows how she succeeded). so we lived on without interruption. my brother alex. was absent from bath for some months every summer, but when at home he took much pleasure in executing some turning or clockmaker's work for his brother." news from hanover put a sudden stop, for a time, to all these labors. the mother wrote, in the utmost distress, to say that dietrich had disappeared from his home, it was supposed with the intention of going to india "with a young idler not older than himself." his brother immediately left the lathe at which he was turning an eye-piece in cocoa-nut, and started for holland, whence he proceeded to hanover, failing to meet his brother, as he expected. meanwhile the sister received a letter to say that dietrich was "laid up very ill" at an inn in wapping. alexander posted to town, removed him to a lodging, and, after a fortnight's nursing, brought him to bath, where, on his brother william's return, he found him being well cared for by his sister. about this time another change was made to the house 19 new king street, which was the last move in bath. it was here that the _georgium sidus_ was discovered. the music still went on. the oratorios of the _messiah_, _judas maccabeus_, and _samson_ were to be performed under herschel's direction, with an orchestra of nearly one hundred pieces. the scores and vocal parts of these carolina copied with her own hands, and the _soprani_ were instructed by her, she being the leading soloist. along with the music went the astronomy. not only were new telescopes made, but they were made for immediate use. the variable star _mira ceti_ was observed, and a long series of lunar observations begun. "in 1779, 1780, and 1781 i measured the heights of about one hundred mountains of the moon, by three different methods. "some of these observations are given in _philosophical transactions_, vol. lxx., but most remain uncalculated in my journal _till some proper opportunity."[12]_ while herschel was measuring these lunar mountains, in december, 1779, he made by chance an acquaintance of much value to him. dr. william watson, a fellow of the royal society, distinguished for his researches in electricity, happened to see him at his telescope, and this led to a visit and an invitation to herschel to join the philosophical society of bath, then forming. this he gladly did, and it was of use to him in many ways. he there formed acquaintance with men of his own way of thinking, and he himself became known. better than all, he learned to measure himself with other men, and by his early papers read to the society, he gained skill in putting his thoughts before his hearers. this skill he never lost, and the merely literary art of his memoirs would make his papers remarkable without their other merits. he is always clear, and in his early papers especially, he appeals to his particular audience--the royal society--in a way which shows that he is conscious of all its weaknesses as well as of its dignity. later, his tone slightly changed. he became less anxious to win his audience, for he had become an authority. this knowledge lent a quiet strength to his style, but never induced the slightest arrogance of spirit or manner. the bath philosophical society has left no printed proceedings. herschel was one of its earliest members, and many papers were communicated to it by his hand. these appear to have been of a very miscellaneous nature. some of them at least would be of the highest interest to us now. in the _philosophical transactions_ for 1789, p. 220, herschel tells us that he communicated to that society "certain mathematical papers" relating to central forces other than the force of gravity, which are or may be concerned in the construction of the sidereal heavens. this early idea was still entertained by herschel in 1789, and the mathematical papers referred to must be contained in the _minutes_ of the society, which on its dissolution were torn from the minute-book and returned to the writers. the earliest published writing of herschel is the answer to the prize question in the "ladies' diary" for 1779, proposed by the celebrated landen, namely: "the length, tension, and weight of a musical string being given, it is required to find how many vibrations it will make in a given time, when a small given weight is fastened to its middle and vibrates with it." in the _philosophical transactions_ of the royal society for 1780, are two papers of his. the title of the first is, _astronomical observations on the periodical star in collo ceti_, by mr. william herschel, of bath. this was communicated to the society by dr. william watson, jr., and was read may 11, 1780, at the same time as the other paper on the mountains of the moon. it is to be noted that herschel was at this time plain "mr. william herschel, of bath." it was only in 1786 that he became "dr. herschel," through the oxford degree of ll.d. neither of these two papers is specially remarkable on its purely astronomical side. the problems examined were such as lay open before all, and the treatment of them was such as would naturally be suggested. the second of these two contained, however, a short description of his newtonian telescope, and he speaks of it with a just pride: "i believe that for distinctness of vision this instrument is perhaps equal to any that was ever made." he was, at least, certain of having obtained excellence in the making of his instruments. in his next paper, however, read january 11, 1781, a subject is approached which shows a different kind of thought. it is the first obvious proof of the truth of the statement which he made long afterwards (1811), when he said: "a knowledge of the construction of the heavens has always been the ultimate object of my observations." the title of this paper was _astronomical observations on the rotation of the planets round their axes, made with a view to determine whether the earth's diurnal motion is perfectly equable_. here the question is a difficult and a remote one, and the method adopted for its solution is perfectly suitable in principle. it marks a step onward from mere observations to philosophizing upon their results. in practical astronomy, too, we note an advance. not only are his results given, but also careful estimates of the errors to be feared in them, and a discussion of the sources of such errors. the same volume of the _philosophical transactions_ which contains this paper, also contains another, _account of a comet_, read april 26, 1781. this comet was the major planet _uranus_, or, as herschel named it, _georgium sidus_. he had found it on the night of tuesday, march 13, 1781. "in examining the small stars in the neighborhood of h _geminorum_, i perceived one that appeared visibly larger than the rest; being struck with its uncommon appearance, i compared it to h _geminorum_ and the small star in the quartile between _auriga_ and _gemini_, and finding it so much larger than either of them, i suspected it to be a comet." the "comet" was observed over all europe. its orbit was computed by various astronomers, and its distance from the sun was found to be nineteen times that of our earth. this was no comet, but a new major planet. the discovery of the amateur astronomer of bath was the most striking since the invention of the telescope. it had absolutely no parallel, for every other major planet had been known from time immemorial.[13] the effect of the discoveries of galileo was felt almost more in the moral than in the scientific world. the mystic number of the planets was broken up by the introduction of four satellites to _jupiter_. that _venus_ emulated the phases of our moon, overthrew superstition and seated the copernican theory firmly. the discovery of "an innumerable multitude of fixed stars" in the milky way confounded the received ideas. this was the great mission of the telescope in galileo's hands. the epoch of mere astronomical discovery began with the detection of the large satellite of _saturn_ by huyghens, in 1655. even then superstition was not dead. huyghens did not search for more moons, because by that discovery he had raised the number of known satellites to six,[14] and because these, with the six planets, made "the perfect number twelve." from 1671 to 1684 cassini discovered four more moons revolving about _saturn_. since 1684 no new body had been added to the solar system. it was thought complete for nearly a century. in england, the remarkable discoveries of bradley (1727-62) had been in the field of practical astronomy, and his example had set the key-note for further researches. france was just about beginning the brilliant period of her discoveries in mathematical astronomy, and had no observatory devoted to investigations like herschel's, with the possible exception of darquier's and flaugergues'. the observatories of schroeter and von hahn, in germany, were not yet active. the field which herschel was created to fill was vacant, the whole world over. it was especially so in england. the royal observatory at greenwich, under maskelyne, a skilful observer, whose work was mostly confined to meridian observations, was no rival to a private observatory like herschel's. the private observatories themselves were but small affairs; those of the king, at kew, of dr. wilson, at glasgow, of mr. aubert, at loampit hill, of the count von bruhl, in london, being perhaps the most important. the whole field was open. what was perhaps more remarkable, there was in england, during herschel's lifetime, no astronomer, public or private, whose talents, even as an observer, lay in the same direction. it hardly need be said that as a philosopher in his science, he had then no rival, as he has had none since. his only associates even, were michell and wilson.[15] without depreciating the abilities of the astronomers of england, his cotemporaries, we may fairly say that herschel stood a great man among a group of small ones. let us endeavor to appreciate the change effected in the state of astronomy not only in england but in the whole world, simply by the discovery of _uranus_. suppose, for example, that the last planet in our system had been _saturn_. no doubt herschel would have gone on. in spite of one and another difficulty, he would have made his ten-foot, his twenty-foot telescopes. his forty-foot would never have been built, and the two satellites which he found with it might not have been discovered. certainly _mimas_ would not have been. his researches on the construction of the heavens would have been made; those were in his brain, and must have been ultimated. the mass of observations of _saturn_, of _jupiter_, of _mars_, of _venus_, would have been made and published. the researches on the sun, on the "invisible rays" of heat, on comets and nebulæ--all these might have been made, printed, and read. but these would have gone into the _philosophical transactions_ as the work of an amateur astronomer, "mr. herschel, of bath." they would have been praised, and they would have been doubted. it would have taken a whole generation to have appreciated them. they would have been severely tried, entirely on their merits, and finally they would have stood where they stand to-day--unrivalled. but through what increased labors these successes would have been gained! it is not merely that the patronage of the king, the subsidies for the forty-foot telescope (£4,000), the comparative ease of herschel's life would have been lacking. it is more than this. it would have been necessary for him to have created the audience to which he appealed, and to have conquered the most persistent of enemies--indifference. certainly, if herschel's mind had been other than it was, the discovery of _uranus_, which brought him honors from every scientific society in the world, and which gave him authority, might have had a hurtful effect. but, as he was, there was nothing which could have aided his career more than this startling discovery. it was needed for him. it completed the solar system far more by affording a free play to a profoundly philosophical mind, than by occupying the vacant spaces beyond _saturn_. his opportunities would have been profoundly modified, though his personal worth would have been the same. "the star that from the zenith darts its beams, visible though it be to half the earth, though half a sphere be conscious of its brightness, is yet of no diviner origin, no purer essence, than the one that burns like an untended watchfire, on the ridge of some dark mountain; or than those that seem humbly to hang, like twinkling winter lamps, among the branches of the leafless trees." to show how completely unknown the private astronomer of bath was at this time, i transcribe a sentence from bode's account of the discovery of _uranus_. "in the _gazette littéraire_ of june, 1781, this worthy man is called mersthel; in julius' _journal encyclopédique_, hertschel; in a letter from mr. maskelyne to m. messier, herthel; in another letter of maskelyne's to herr mayer, at mannheim, herrschell; m. darquier calls him hermstel. what may his name be? he must have been born a _german_."[16] this obscurity did not long continue. the news spread quickly from fashionable bath to london. on the 6th of december, 1781, herschel was elected a fellow of the royal society, to which he was formally "admitted" may 30, 1782. he was forty-three years old. he also received the copley medal in 1781 for his "discovery of a new and singular star."[17] . . . "he was now frequently interrupted by visitors who were introduced by some of his resident scholars, among whom i remember sir harry engelfield, dr. blagden, and dr. maskelyne. with the latter he was engaged in a long conversation, which to me sounded like quarrelling, and the first words my brother said after he was gone were: 'that is a devil of a fellow.'. . . "i suppose their names were often not known, or were forgotten; for it was not till the year 1782 or 1783 that a memorandum of the names of visitors was thought of.". . . "my brother now applied himself to perfect his mirrors, erecting in his garden a stand for his twenty-foot telescope; many trials were necessary before the required motions for such an unwieldy machine could be contrived. many attempts were made by way of experiment before an intended thirty-foot telescope could be completed, for which, between whiles (not interrupting the observations with seven, ten, and twenty-foot, and writing papers for both the royal and bath philosophical societies), gauges, shapes, weight, etc., of the mirror were calculated, and trials of the composition of the metal were made. in short, i saw nothing else and heard nothing else talked of but these things when my brothers were together. alex. was always very alert, assisting when anything new was going forward, but he wanted perseverance, and never liked to confine himself at home for many hours together. and so it happened that my brother william was obliged to make trial of my abilities in copying for him catalogues, tables, etc., and sometimes whole papers which were lent him for his perusal. among them was one by mr. michell and a catalogue of christian mayer, in latin, which kept me employed when my brother was at the telescope at night. when i found that a hand was sometimes wanted when any particular measures were to be made with the lamp micrometer, etc., or a fire to be kept up, or a dish of coffee necessary during a long night's watching, i undertook with pleasure what others might have thought a hardship. . . . since the discovery of the _georgium sidus_ [march 13, 1781], i believe few men of learning or consequence left bath before they had seen and conversed with its discoverer, and thought themselves fortunate in finding him at home on their repeated visits. sir william watson was almost an intimate, for hardly a day passed but he had something to communicate from the letters which he received from sir joseph banks, and other members of the royal society, from which it appeared that my brother was expected in town to receive the gold medal. the end of november was the most precarious season for absenting himself. but sir william watson went with him, and it was arranged so that they set out with the diligence at night, and by that means his absence did not last above three or four days, when my brother returned alone, sir william remaining with his father. "now a very busy winter was commencing; for my brother had engaged himself to conduct the oratorios conjointly with ronzini, and had made himself answerable for the payment of the engaged performers, for his credit ever stood high in the opinion of every one he had to deal with. (he lost considerably by this arrangement.) but, though at times much harassed with business, the mirror for the thirty-foot reflector was never out of his mind, and if a minute could but be spared in going from one scholar to another, or giving one the slip, he called at home to see how the men went on with the furnace, which was built in a room below, even with the garden. "the mirror was to be cast in a mould of loam, of which an immense quantity was to be pounded in a mortar and sifted through a fine sieve. it was an endless piece of work, and served me for many an hour's exercise; and alex. frequently took his turn at it, for we were all eager to do something towards the great undertaking. even sir william watson would sometimes take the pestle from me when he found me in the work-room, where he expected to find his friend, in whose concerns he took so much interest that he felt much disappointed at not being allowed to pay for the metal. but i do not think my brother ever accepted pecuniary assistance from any one of his friends, and on this occasion he declined the offer by saying it was paid for already. "among the bath visitors were many philosophical gentlemen who used to frequent the levées at st. james's, when in town. colonel walsh, in particular, informed my brother that from a conversation he had had with his majesty, it appeared that in the spring he was to come with his seven-foot telescope to the king. similar reports he received from many others, but they made no great impression nor caused any interruption in his occupation or study, and as soon as the season for the concerts was over, and the mould, etc., in readiness, a day was set apart for casting, and the metal was in the furnace. unfortunately it began to leak at the moment when ready for pouring, and both my brothers and the caster, with his men, were obliged to run out at opposite doors, for the stone flooring (which ought to have been taken up) flew about in all directions as high as the ceiling. before the second casting was attempted, everything which could insure success had been attended to, and a very perfect metal was found in the mould. "but a total stop and derangement now took place, and nearly six or seven months elapsed before my brother could return to the undisturbed enjoyment of his instruments and observations. for one morning in passion week, as sir william watson was with my brother, talking about the pending journey to town, my eldest nephew arrived to pay us a visit, and brought the confirmation that his uncle was expected with his instrument in town. . . . we had not one night in the week, except friday, but what was set apart for an oratorio either at bath or bristol. soon after easter, a new organ being erected in st. james's church, it was opened with two performances of the 'messiah;' this again took up some of my brother's time.". . . in may of 1782 herschel went to london. "but when almost double the time had elapsed which my brother could safely be absent from his scholars, alex., as well as myself, were much at a loss how to answer their inquiries, for, from the letters we received, we could learn nothing but that he had been introduced to the king and queen, and had permission to come to the concerts at buckingham house, where the king conversed with him about astronomy." it was during his absence at this time that the three following letters were written and received: "dear lina:- "i have had an audience of his majesty this morning, and met with a very gracious reception. i presented him with the drawing of the solar system, and had the honor of explaining it to him and the queen. my telescope is in three weeks' time to go to richmond, and meanwhile to be put up at greenwich, where i shall accordingly carry it to-day. so you see, lina, that you must not think of seeing me in less than a month. i shall write to miss lee myself; and other scholars who inquire for me, you may tell that i cannot wait on them till his majesty shall be pleased to give me leave to return, or rather to dismiss me, for till then i must attend. i will also write to mr. palmer to acquaint him with it. "i am in a great hurry, therefore can write no more at present. tell alexander that everything looks very likely as if i were to stay here. the king inquired after him, and after my great speculum. he also gave me leave to come to hear the griesbachs play at the private concert which he has every evening. my having seen the king need not be kept a secret, but about my staying here it will be best not to say anything, but only that i must remain here till his majesty has observed the planets with my telescope. "yesterday i dined with colonel walsh, who inquired after you. there were mr. aubert and dr. maskelyne. dr. maskelyne in public declared his obligations to me for having introduced to them the high powers, for mr. aubert has so much succeeded with them that he says he looks down upon 200, 300, or 400 with contempt, and immediately begins with 800. he has used 2,500 very completely, and seen my fine double stars with them. all my papers are printing, with the postscript and all, and are allowed to be very valuable. you see, lina, i tell you all these things. you know vanity is not my foible, therefore i need not fear your censure. farewell. "i am, your affectionate brother, "wm. herschel. "saturday morning, "probably _may 25, 1782_." to miss herschel. "monday evening, _june 3, 1782._ "dear lina:- "i pass my time between greenwich and london agreeably enough, but am rather at a loss for work that i like. company is not always pleasing, and i would much rather be polishing a speculum. last friday i was at the king's concert to hear george play. the king spoke to me as soon as he saw me, and kept me in conversation for half an hour. he asked george to play a solo-concerto on purpose that i might hear him; and george plays extremely well, is very much improved, and the king likes him very much. these two last nights i have been star-gazing at greenwich with dr. maskelyne and mr. aubert. we have compared our telescopes together, and mine was found very superior to any of the royal observatory. double stars which they could not see with their instruments i had the pleasure to show them very plainly, and my mechanism is so much approved of that dr. maskelyne has already ordered a model to be taken from mine, and a stand to be made by it to his reflector. he is, however, now so much out of love with his instrument that he begins to doubt whether it _deserves_ a new stand. "i am introduced to the best company. to-morrow i dine at lord palmerston's, next day with sir joseph banks, etc., etc. among opticians and astronomers nothing now is talked of but _what they call_ my great discoveries. alas! this shows how far they are behind, when such trifles as i have seen and done are called _great_. let me but get at it again! i will make such telescopes, and see such things--that is, i will endeavor to do so." to miss herschel. "_july 3, 1782._" "dear carolina:- "i have been so much employed that you will not wonder at my not writing sooner. the letter you sent me last monday came very safe to me. as dr. watson has been so good as to acquaint you and alexander with my situation, i was still more easy in my silence to you. last night the king, the queen, the prince of wales, the princess royal, princess sophia, princess augusta, etc., duke of montague, dr. heberden, m. de luc, etc., etc., saw my telescope, and it was a very fine evening. my instrument gave general satisfaction. the king has very good eyes, and enjoys observations with telescopes exceedingly. "this evening, as the king and queen are gone to kew, the princesses were desirous of seeing my telescope, but wanted to know if it was possible to see without going out on the grass, and were much pleased when they heard that my telescope could be carried into any place they liked best to have it. about eight o'clock it was moved into the queen's apartments, and we waited some time in hopes of seeing _jupiter_ or _saturn_. meanwhile i showed the princesses, and several other ladies who were present, the speculum, the micrometers, the movements of the telescopes, and other things that seemed to excite their curiosity. when the evening appeared to be totally unpromising, i proposed an artificial _saturn_ as an object, since we could not have the real one. i had beforehand prepared this little piece, as i guessed by the appearance of the weather in the afternoon we should have no stars to look at. this being accepted with great pleasure, i had the lamps lighted up which illuminated the picture of a _saturn_ (cut out in pasteboard) at the bottom of the garden wall. the effect was fine, and so natural that the best astronomer might have been deceived. their royal highnesses and other ladies seemed to be much pleased with the artifice. "i remained in the queen's apartment with the ladies till about half after ten; when in conversation with them i found them extremely well instructed in every subject that was introduced, and they seemed to be most amiable characters. to-morrow evening they hope to have better luck, and nothing will give me greater happiness than to be able to show them some of those beautiful objects with which the heavens are so gloriously ornamented." carolina's diary goes on: "sir william watson returned to bath after a fort-night or three weeks' stay. from him we heard that my brother was invited to greenwich with the telescope, where he was met by a numerous party of astronomical and learned gentlemen, and trials of his instrument were made. in these letters he complained of being obliged to lead an idle life, having nothing to do but to pass between london and greenwich. sir william received many letters, which he was so kind as to communicate to us. by these, and from those to alexander or to me, we learned that the king wished to see the telescope at windsor. at last a letter, dated july 2, arrived from therese, and from this and several succeeding ones we gathered that the king would not suffer my brother to return to his profession again, and by his writing several times for a supply of money we could only suppose that he himself was in uncertainty about the time of his return. "in the last week of july my brother came home, and immediately prepared for removing to datchet, where he had taken a house with a garden and grass-plat annexed, quite suitable for the purpose of an observing-place. sir william watson spent nearly the whole time at our house, and he was not the only friend who truly grieved at my brother's going from bath; or feared his having perhaps agreed to no very advantageous offers; their fears were, in fact, not without reason. . . . the prospect of entering again on the toils of teaching, etc., which awaited my brother at home (the months of leisure being now almost gone by), appeared to him an intolerable waste of time, and by way of alternative he chose to be royal astronomer, with a salary of £200 a year. sir william watson was the only one to whom the sum was mentioned, and he exclaimed, 'never bought monarch honor so cheap!' to every other inquirer, my brother's answer was that the king had provided for him." on the 1st of august, 1782, the family removed to datchet. the last musical duty was performed on whit-sunday, 1782, in st. margaret's chapel, bath, when the anthem for the day was of herschel's own composition. the end of the introductory epoch of his life is reached. henceforth he lived in his observatory, and from his forty-fourth year onwards he only left it for short periods to go to london to submit his classic memoirs to the royal society. even for these occasions he chose periods of moonlight, when no observations could be made. he was a private man no longer. henceforth he belongs to the whole world. footnotes: [10] probably on the model of one of short's gregorian telescopes, which were then the best instruments of the kind. [11] for a description of the main points of herschel's processes of making reflectors, which will illustrate his strong mechanical talents, see _encyclopædia britannica_, eighth edition, article _telescope_. [12] these have never been published, nor is it likely at this day, when our measuring instruments are so greatly improved, that they would be of any material value to science, although of interest as giving the proofs of herschel's assiduity and skill. he was always more than the maker of telescopes, for he was never content until they were applied to the problems of astronomy. [13] arago has implied that if herschel had directed his telescope to _uranus_ only eleven days earlier than he did, this discovery would have escaped him, since at that time (march 2, 1781) the planet was at its _station_, and had no motion relative to the star. this is an entire misconception, since the new planet was detected by its physical appearance, and not by its motion. does any one suppose that "a new and singular star" like this would have been once viewed and then forgotten? [14] four of _jupiter_, one of the earth, and one of _saturn_. [15] john michell had been a member of the royal society since 1760: he died in 1793. he was a philosophical thinker, as is shown by his memoirs on the distances of the stars, and by his invention of the method for determining the earth's density. it is not certain that he was personally known to herschel, although his writings were familiar to the latter. alexander wilson was professor of astronomy at glasgow, and is chiefly known to us by his theory of the nature of the solar spots, which was adopted and enlarged by herschel. he died in 1786; but the families of wilson and herschel remained close friends. [16] _berliner jahrbuch_, 1784, p. 211. in the _connaissance des tems_ for 1784 he is called "horochelle." [17] at the presentation sir joseph banks, the president of the royal society, said: "in the name of the royal society i present to you this gold medal, the reward which they have assigned to your successful labors, and i exhort you to continue diligently to cultivate those fields of science which have produced to you a harvest of so much honor. your attention to the improvement of telescopes has already amply repaid the labor which you have bestowed upon them; but the treasures of the heavens are well known to be inexhaustible. who can say but your new star, which exceeds _saturn_ in its distance from the sun, may exceed him as much in magnificence of attendance? who knows what new rings, new satellites, or what other nameless and numberless phenomena remain behind, waiting to reward future industry and improvement?" chapter iii. life at datchet, clay hall, and slough; 1782-1822. the new house at datchet, which was occupied from 1782 till 1785, was a source of despair to carolina herschel, who looked upon its desolate and isolated condition with a housekeeper's eyes. this was nothing to her brother, who gayly consented to live upon "eggs and bacon," now that he was free at last to mind the heavens. the ruinous state of the place had no terrors in his eyes, for was there not a laundry which would serve as a library, a large stable which was just the place for the grinding of mirrors, and a grass-plat for the small twenty-foot reflector? here they set to work at astronomy; the brother with the twenty-foot, the sister aiding him, and at odd times sweeping for comets. in the course of her life she discovered no less than eight, and five of these were first seen by her. * * * * * in 1787 herschel wrote his paper "on three volcanoes in the moon," which he had observed in april of that year. in this he mentions previous observations of the same sort. i do not remember that the following account of these has ever been put on record in english. baron von zach writes from london to bode:[18] "probably you have heard also of the volcanoes in the moon, which herschel has observed. . . . i will give you an account of it as i heard it from his own lips. dr. lind, a worthy physician in windsor, who has made himself known through his two journeys in china, and who is a friend of our herschel's, was with his wife one evening on a visit to herschel in datchet [1783, may 4]. on this evening there was to be an occultation of a star at the moon's dark limb. this was observed by herschel and doctor lind. mrs. lind wished also to see what was occurring, and placed herself at a telescope and watched attentively. "scarcely had the star disappeared before mrs. lind thought she saw it again, and exclaimed that the star had gone in front of, and not behind the moon. this provoked a short astronomical lecture on the question, but still she would not credit it, because she _saw_ differently. finally herschel stepped to the telescope, and in fact he saw a bright point on the dark disc of the moon, which he followed attentively. it gradually became fainter and finally vanished.". . . the life at datchet was not free from its annoyances. "much of my brother's time was taken up in going, when the evenings were clear, to the queen's lodge, to show the king, etc., objects through the seven-foot. but when the days began to shorten, this was found impossible, for the telescope was often (at no small expense and risk of damage) obliged to be transported in the dark back to datchet, for the purpose of spending the rest of the night with observations on double stars for a second catalogue. my brother was, besides, obliged to be absent for a week or ten days, for the purpose of bringing home the metal of the cracked thirty-foot mirror, and the remaining materials from his work-room. before the furnace was taken down at bath, a second twenty-foot mirror, twelve inches diameter, was cast, which happened to be very fortunate, for on the 1st of january, 1783, a very fine one cracked by frost in the tube. . . . "in my brother's absence from home i was, of course, left alone to amuse myself with my own thoughts, which were anything but cheerful. i found i was to be trained for an assistant astronomer, and, by way of encouragement, a telescope adapted for 'sweeping,' consisting of a tube with two glasses, such as are commonly used in a 'finder,' was given me. i was 'to sweep for comets,' and i see, by my journal, that i began august 22d, 1782, to write down and describe all remarkable appearances i saw in my 'sweeps,' which were horizontal. but it was not till the last two months of the same year that i felt the least encouragement to spend the star-light nights on a grass-plot covered with dew or hoar-frost, without a human being near enough to be within call. i knew too little of the real heavens to be able to point out every object so as to find it again, without losing much time by consulting the atlas. but all these troubles were removed when i knew my brother to be at no great distance making observations, with his various instruments, on double stars, planets, etc., and when i could have his assistance immediately if i found a nebula or cluster of stars, of which i intended to give a catalogue; but, at the end of 1783, i had only marked fourteen, when my sweeping was interrupted by being employed to write down my brother's observations with the large twenty-foot. i had, however, the comfort to see that my brother was satisfied with my endeavors to assist him when he wanted another person either to run to the clocks, write down a memorandum, fetch and carry instruments, or measure the ground with poles, etc., etc., of which something of the kind every moment would occur. for the assiduity with which the measurements on the diameter of the _georgium sidus_, and observations of other planets, double stars, etc., etc., were made, was incredible, as may be seen by the various papers that were given to the royal society in 1783, which papers were written in the daytime, or when cloudy nights interfered. besides this, the twelve-inch speculum was perfected before the spring, and many hours were spent at the turning-bench, as not a night clear enough for observing ever passed but that some improvements were planned for perfecting the mounting and motions of the various instruments then in use, or some trials were made of new constructed eye-pieces, which were mostly executed by my brother's own hands. wishing to save his time, he began to have some work of that kind done by a watchmaker who had retired from business and lived on datchet common; but the work was so bad, and the charges so unreasonable, that he could not be employed. it was not till some time afterwards, in his frequent visits to the meetings of the royal society (made in moonlight nights), that he had an opportunity of looking about for mathematical workmen, opticians, and founders. but the work seldom answered expectation, and it was kept, to be executed with improvements by alexander during the few months he spent with us. "the summer months passed in the most active preparation for getting the large twenty-foot ready against the next winter. the carpenters and smiths of datchet were in daily requisition, and, as soon as patterns for tools and mirrors were ready, my brother went to town to have them cast, and, during the three or four months alexander could be absent from bath, the mirrors and optical parts were nearly completed. "but that the nights after a day of toil were not given to rest, may be seen by the observations on _mars_, of which a paper, dated december 1, 1783, was given to the royal society. some trouble, also, was often thrown away, during those nights, in the attempt to teach me to remeasure double stars with the same micrometers with which former measures had been taken, and the small twenty-foot was given me for that purpose. . . . i had also to ascertain their places by a transit instrument lent for that purpose by mr. dalrymple; but, after many fruitless attempts, it was seen that the instrument was, perhaps, as much in fault as my observations." in 1783 herschel says: "i have now finished my third review of the heavens. the first was made with a newtonian telescope something less than seven feet focal length, a power of 222, and an aperture of four and a half inches. it extended only to stars of the first, second, third, and fourth magnitudes. my second review was made with an instrument much superior to the other, of 85.2 inches focus, 6.2 inches aperture, and power 227. it extended to all the stars of harris's maps and the telescopic ones near them, as far as the eighth magnitude. the catalogue of double stars and the discovery of the _georgium sidus_, were the results of that review. the third was with the same instrument and aperture, but with a power of 460. this review extended to all the stars of flamsteed's catalogue, together with every small star about them, to the amount of a great many thousands of stars. i have, many a night, in the course of eleven or twelve hours of observation, carefully and singly examined not less than 400 celestial objects, besides taking measures, and sometimes viewing a particular star for half an hour together." the fourth review began with the twenty-foot, in 1784. "my brother began his series of sweeps when the instrument was yet in a very unfinished state, and my feelings were not very comfortable when every moment i was alarmed by a crack or fall, knowing him to be elevated fifteen feet or more on a temporary cross-beam, instead of a safe gallery. the ladders had not even their braces at the bottom; and one night, in a very high wind, he had hardly touched the ground before the whole apparatus came down. some laboring men were called up to help in extricating the mirror, which was, fortunately, uninjured, but much work was cut out for carpenters next day. i could give a pretty long list of accidents which were near proving fatal to my brother as well as myself. to make observations with such large machinery, where all around is in darkness, is not unattended with danger, especially when personal safety is the last thing with which the mind is occupied; even poor piazzi did not go home without getting broken shins by falling over the rack-bar. "in the long days of the summer months many ten and seven foot mirrors were finished; there was nothing but grinding and polishing to be seen. for ten-foot, several had been cast with ribbed backs, by way of experiment, to reduce the weight in large mirrors. in my leisure hours i ground seven-foot and plain mirrors from rough to fining down, and was _indulged_ with polishing and the last finishing of a very beautiful mirror for sir william watson. "an account of the discoveries made with the twenty-foot and the improvements of the mechanical parts of the instrument during the winter of 1785 is given with the catalogue of the first 1,000 new nebulæ. by which account it must plainly appear that the expenses of these improvements, and those which were yet to be made in the apparatus of the twenty-foot (which, in fact, proved to be a model of a larger instrument), could not be supplied out of a salary of £200 a year, especially as my brother's finances had been too much reduced during the six months before he received his _first_ quarterly payment of _fifty pounds_ (which was michaelmas, 1782). travelling from bath to london, greenwich, windsor, backwards and forwards, transporting the telescope, etc., breaking up his establishment at bath and forming a new one near the court, all this, even leaving such personal conveniences as he had for many years been used to, out of the question, could not be obtained for a trifle; a good large piece of ground was required for the use of the instruments, and a habitation in which he could receive and offer a bed to an astronomical friend, was necessary after a night's observation. "it seemed to be supposed that enough had been done when my brother was enabled to leave his profession that he might have time to make and sell telescopes. the king ordered four ten-foot himself, and many seven-foot besides had been bespoke, and much time had already been expended on polishing the mirrors for the same. but all this was only retarding the work of a thirty or forty foot instrument, which it was my brother's chief object to obtain as soon as possible; for he was then on the wrong side of forty-five, and felt how great an injustice he would be doing to himself and to the cause of astronomy by giving up his time to making telescopes for other observers. "sir william watson, who often in the lifetime of his father came to make some stay with us at datchet, saw my brother's difficulties, and expressed great dissatisfaction. on his return to bath he met, among the visitors there, several belonging to the court, to whom he gave his opinion concerning his friend and his situation very freely. in consequence of this, my brother had soon after, through sir j. banks, the promise that £2,000 would be granted for enabling him to make himself an instrument. "immediately every preparation for beginning the great work commenced. a very ingenious smith (campion), who was seeking employment, was secured by my brother, and a temporary forge erected in an upstairs room." the sale of these telescopes of herschel's must have produced a large sum, for he had made before 1795 more than two hundred seven-feet, one hundred and fifty ten-feet, and eighty twenty-feet mirrors. for many of the telescopes sent abroad no stands were constructed. the mirrors and eye-pieces alone were furnished, and a drawing of the stand sent with them by which the mirrors could be mounted. in 1785 the cost of a seven-foot telescope, six and four-tenths inches aperture, stand, eye-pieces, etc., complete, was two hundred guineas, a ten-foot was six hundred guineas, and a twenty-foot about 2,500 to 3,000 guineas. he had made four ten-foot telescopes like this for the king. in 1787 schroeter got the mirrors and eye-pieces only for a four-and-three-quarter-inch reflector for five guineas; those for his seven-foot telescope were twenty-three guineas. later a seven-foot telescope, complete, was sold for one hundred guineas, and the twenty-five-foot reflector, made for the madrid observatory, cost them 75,000 francs = $15,000.[19] it was ordered in 1796, but not delivered for several years, the spanish government being short of money. for a ten and a seven foot telescope, the prince of canino paid £2,310. von magellan writes to bode concerning a visit to herschel:[20] "i spent the night of the 6th of january at herschel's, in datchet, near windsor, and had the good luck to hit on a fine evening. he has his twenty-foot newtonian telescope in the open air and mounted in his garden very simply and conveniently. it is moved by an assistant, who stands below it. . . . near the instrument is a clock regulated to sidereal time. . . . in the room near it sits herschel's sister, and she has flamsteed's atlas open before her. as he gives her the word, she writes down the declination and right ascension and the other circumstances of the observation. in this way herschel examines the whole sky without omitting the least part. he commonly observes with a magnifying power of one hundred and fifty, and is sure that after four or five years he will have passed in review every object above our horizon. he showed me the book in which his observations up to this time are written, and i am astonished at the great number of them. each sweep covers 2° 15' in declination, and he lets each star pass at least three times through the field of his telescope, so that it is impossible that anything can escape him. he has already found about 900 double stars and almost as many nebulæ. i went to bed about one o'clock, and up to that time, he had found that night four or five new nebulæ. the thermometer in the garden stood at 13° fahrenheit; but, in spite of this, herschel observes the whole night through, except that he stops every three or four hours and goes in the room for a few moments. for some years herschel has observed the heavens every hour when the weather is clear, and this always in the open air, because he says that the telescope only performs well when it is at the same temperature as the air. he protects himself against the weather by putting on more clothing. he has an excellent constitution, and thinks about nothing else in the world but the celestial bodies. he has promised me in the most cordial way, entirely in the service of astronomy, and without thinking of his own interest, to see to the telescopes i have ordered for european observatories, and he will himself attend to the preparation of the mirrors." it was at this time, 1783, may 8, that herschel married. his wife was the daughter of mr. james baldwin, a merchant of the city of london, and the widow of john pitt, esq. she is described as a lady of singular amiability and gentleness of character. she was entirely interested in his scientific pursuits, and the jointure which she brought removed all further anxiety about money affairs. they had but one child, john frederick william, born march 7, 1792.[21] * * * * * the house at datchet became more and more unfit for the needs of the family, and in june, 1785, a move was made to clay hall, in old windsor. the residence here was but short, and finally a last change was made to slough on april, 3d, 1786. the ardor of the work during these years can be judged of by a single sentence from carolina herschel's diary: "the last night at clay hall was spent in sweeping till daylight, and by the next evening the telescope stood ready for observation at slough." from 1786 until his death, herschel remained at slough; his life, truly speaking, was in his observatory. it is indeed true, as arago has said in his eloquent tribute to him: "on peut dire hardiment du jardin et de la petite maison de slough, que c'est le lieu du monde où il a été fait le plus de découvertes. le nom de ce village ne périra pas; les sciences le transmettront religieusement à nos derniers neveux." herschel's first contribution to the _philosophical transactions_ was printed in the volume for 1780, his last in that for 1818. of these thirty-nine volumes, there are only two (1813 and 1817) which contain no paper from his hand, and many volumes contain more than one, as he published no less than sixty-eight memoirs in this place. and yet it must not be thought that his was an austere and grave existence. music, which he loved to enthusiasm, was still a delight to him. all the more that his devotion was free. the glimpses which we get of his life with his friends show him always cheerful, ardent, and devoted. even in his later years, he had not lost a "boyish earnestness to explain;" his simplicity and the charm of his manner struck every one. "herschel, you know, and everybody knows, is one of the most pleasing and well-bred natural characters of the present age," says dr. burney, who had opportunity to know. the portrait which is given in the frontispiece must have been painted about this time (1788), and the eager, ardent face shows his inner life far better than any words can do. even in his scientific writings, which everything conspired to render grave and sober, the almost poetic nature of his mind shows forth. in one of his (unpublished) note-books, now in the royal society's library, i found this entry: "640th sweep--november 28, 1786.--the nebula of _orion_, which i saw by the front view, was so glaring and beautiful that i could not think of taking any place of its extent." he was quite alone under the perfectly silent sky when this was written, and he was at his post simply to make this and other such observations. but the sky was beautiful to him, and his faithful sister, carolina, sitting below, has preserved for us the words as they dropped from his lips. on the 11th of january, 1787, herschel discovered two satellites to _uranus_. after he had well assured himself of their existence, but before he communicated his discovery to the world, he made this crucial test. he prepared a sketch of _uranus_ attended by his two satellites, as it would appear on the night of february 10, 1787, and when the night came, "the heavens displayed the original of my drawings, by showing in the situation i had delineated them _the georgian planet attended by two satellites_. i confess that this scene appeared to me with additional beauty, as the little secondary planets seemed to give a dignity to the primary one which raises it into a more conspicuous situation among the great bodies of the solar system.". . . in a memoir of 1789, he has a few sentences which show the living way in which the heavens appeared to him: "this method of viewing the heavens seems to throw them into a new kind of light. "they are now seen to resemble a luxuriant garden, which contains the greatest variety of productions in different flourishing beds; and one advantage we may at least reap from it is, that we can, as it were, extend the range of our experience to an immense duration. for is it not almost the same thing whether we live successively to witness the germination, blooming, foliage, fecundity, fading, withering, and corruption of a plant, or whether a vast number of specimens selected from every stage through which the plant passes in the course of its existence be brought at once to our view?" the thought here is no less finely expressed than it is profound. the simile is perfect, if we have the power to separate among the vast variety each state of being from every other, and if the very luxuriance of illustration in the heavens does not bewilder and overpower the mind. it was precisely this discriminating power that herschel possessed in perfection. there is a kind of humor in the way he records a change of opinion: "i formerly supposed the surface of _saturn's_ ring to be rough, owing to luminous points like mountains seen on it, till one of these was kind enough to venture off the edge of the ring and appear as a satellite." in 1782 he replies with a certain concealed sharpness to the idea that he used magnifying powers which were too high. there is a tone almost of impatience, as if he were conscious he was replying to a criticism based on ignorance: "we are told that we gain nothing by magnifying too much. i grant it; but shall never believe i magnify too much till by experience i find that i can see better with a lower power." (1782.) by 1786, when he returns to this subject, in answer to a formal request to explain his use of high magnifiers, he is quite over any irritation, and treats the subject almost with playfulness: "soon after my first essay of using high powers with the newtonian telescope, i began to doubt whether an opinion which has been entertained by several eminent authors, 'that vision will grow indistinct when the optic pencils are less than the fiftieth part of an inch,' would hold good in all cases. i perceived that according to this criterion i was not entitled to see distinctly with a power of much more than about 320 in a seven-foot telescope of an aperture of six and four-tenths inches, whereas in many experiments i found myself very well pleased with magnifiers which far exceeded such narrow limits. this induced me, as it were, by way of apology to myself for seeing well where i ought to have seen less distinctly, to make a few experiments." it is needless to say that these experiments proved that from the point of view taken by herschel, he was quite right, and that his high powers had numerous valuable applications. he goes on to say: "had it not been for a late conversation with some of my highly esteemed and learned friends, i might probably have left the papers on which these experiments were recorded, among the rest of those that are laid aside, when they have afforded me the information i want." the last sentence seems to be a kind of notice to his learned friends that there is yet more unsaid. as a warning to those to whose criticisms he had replied, he gives them this picture of the kind of assiduity which will be required, if some of his observations on double stars are to be repeated: "it is in vain to look for these stars if every circumstance is not favorable. the observer as well as the instrument must have been long enough out in the open air to acquire the same temperature. in very cold weather an hour at least will be required." (1782.) we may gain some further insight into his character from the following chance extracts from his writings: "i have all along had truth and reality in view as the sole object of my endeavors." (1782.) "not being satisfied when i thought it possible to obtain more accurate measures, i employed [a more delicate apparatus]." (1783.) "to this end i have already begun a series of observations upon several zones of double stars, and should the result of them be against these conjectures, i shall be the first to point out their fallacy." (1783.) "there is a great probability of succeeding still farther in this laborious but delightful research, so as to be able at last to say not only how much the annual parallax _is not_, but how much it really _is_." (1782.) the nature of his philosophizing, and the limits which he set to himself, may be more clearly seen in further extracts: "by taking more time [before printing these observations] i should undoubtedly be enabled to speak more confidently of the _interior_ _construction of the heavens_, and of its various _nebulous_ and sidereal strata. as an apology for this prematurity it may be said that, the end of all discoveries being communication, we can never be too ready in giving facts and observations, whatever we may be in reasoning upon them." (1785.) "in an investigation of this delicate nature we ought to avoid two opposite extremes. if we indulge a fanciful imagination, and build worlds of our own, we must not wonder at our going wide from the path of truth and nature. on the other hand, if we add observation to observation without attempting to draw not only certain conclusions but also conjectural views from them, we offend against the very end for which only observations ought to be made. i will endeavor to keep a proper medium, but if i should deviate from that, i could wish not to fall into the latter error." (1785.) "as observations carefully made should always take the lead of theories, i shall not be concerned if what i have to say contradicts what has been said in my last paper on this subject." (1790.) no course of reasoning could be more simple, more exact, more profound, and more beautiful than this which follows: "as it has been shown that the spherical figure of a cluster is owing to the action of central powers, it follows that those clusters which, _cæteris paribus_, are the most complete in this figure, must have been the longest exposed to the action of these causes. thus the maturity of a sidereal system may be judged from the disposition of the component parts. "hence planetary nebulæ may be looked on as very aged. though we cannot see any individual nebula pass through all its stages of life, we can select particular ones in each peculiar stage." (1789.) there is something almost grandiose and majestic in his statement of the ultimate destiny of the galaxy: "to him the fates were known of orbs dim hovering on the skirts of space." "--since the stars of the milky way are permanently exposed to the action of a power whereby they are irresistibly drawn into groups, we may be certain that from mere clustering stars they will be gradually compressed, through successive stages of accumulation, till they come up to what may be called the ripening period of the globular form, and total insulation; from which it is evident that the milky way must be finally broken up and cease to be a stratum of scattered stars. "the state into which the incessant action of the clustering power has brought it at present, is a kind of chronometer that may be used to measure the time of its past and future existence; and although we do not know the rate of going of this mysterious chronometer, it is nevertheless certain that since the breaking up of the milky way affords a proof that it cannot last forever, it equally bears witness that its past duration cannot be admitted to be infinite." (1814.) herschel's relations with his cotemporaries were usually of the most pleasant character, though seldom intimate. this peace was broken but by one unpleasant occurrence. in the _philosophical transactions_ for 1792, schroeter had communicated a series of observations made with one of herschel's own telescopes on the atmospheres of _venus_, the moon, etc. it was not only an account of phenomena which had been seen; it was accompanied by measures, and the computations based on these led to heights and dimensions for mountains on _venus_ which were, to say the least, extravagant. the adjective will not seem too strong when we say that the very existence of the mountains themselves is to-day more than doubtful. the appearances seen by schroeter were described by him in perfectly good faith, and similar ones have been since recorded. his reasoning upon them was defective, and the measures which he made were practically valueless. this paper, printed in the _transactions_ of the royal society, to which schroeter had not before contributed, appears to have irritated herschel. no doubt there were not wanting members of his own society who hinted that on the continent, too, there were to be found great observers, and that here, at least, herschel had been anticipated even in his own field. i have always thought that the memoir of herschel which appeared in the next volume of the _transactions_ (1793), _observations on the planet venus_, was a rejoinder intended far more for the detractors at home than for the astronomer abroad. the review is conceived in a severe spirit. the first idea seems to be to crush an opposition which he feels. the truth is established, but its establishment is hardly the _first_ object. it seems as if herschel had almost allowed himself to be forced into a position of arrogance, which his whole life shows was entirely foreign to his nature. all through the review he does not once mention schroeter's name. he says: "a series of observations on _venus_, begun by me in april, 1777, has been continued down to the present time. . . . the result of my observations would have been communicated long ago if i had not flattered myself with the hope of some better success concerning the diurnal motion of _venus_, which has still eluded my constant attention as far as concerns its period and direction. . . . even at this present time i should hesitate to give the following extracts if it did not seem incumbent on me to examine by what accident i came to overlook mountains in this planet of such enormous height as to exceed four, five, or even six times the perpendicular height of chimboraço, the highest of our mountains. . . . the same paper contains other particulars concerning _venus_ and _saturn_. all of which being things of which i have never taken any notice, it will not be amiss to show, by what follows, that neither want of attention, nor a deficiency of instruments, would occasion my not perceiving these mountains of more than twenty-three miles in height, this jagged border of _venus_, and these flat, spherical forms on _saturn_." the reply of schroeter (1795) is temperate and just. it does him honor, and he generously gives full justice to his critic. it would hardly be worth while to mention this slight incident if it were not that during these years there certainly existed a feeling that herschel undervalued the labors of his cotemporaries. this impression was fostered no doubt by his general habit of not quoting previous authorities in the fields which he was working. a careful reading of his papers will, i think, show that his definite indebtedness to his _cotemporaries_ was vanishingly small. the work of michell and wilson he alludes to again and again, and always with appreciation. certainly he seems to show a vein of annoyance that the papers of christian mayer, _de novis in coelo sidereo phænomenis_ (1779), and _beobachtungen von fixsterntrabanten_ (1778), should have been quoted to prove that the method proposed by herschel in 1782 for ascertaining the parallax of the fixed stars by means of observations of those which were double, was not entirely original with himself. there is direct proof that it was so,[22] and if this was not forthcoming it would be unnecessary, as he has amply shown in his catalogue of double stars. one is reminded of his remarks on the use of the high magnifying powers by the impatience of his comments. his proposal to call the newly discovered minor planets _asteroids_ (1802) was received as a sign that he wished to discriminate between the discoveries of piazzi and olbers and his own discovery of uranus.[23] he takes pains to quietly put this on one side in one of his papers, showing that he was cognizant of the existence of such a feeling. i am tempted to resurrect from a deserved obscurity a notice of herschel's _observations on the two lately discovered celestial bodies_ (_philosophical transactions_, 1802), printed in the first volume of the _edinburgh review_, simply to show the kind of envy to which even he, the glory of england, was subject. the reviewer sets forth the principal results of herschel's observations, and, after quoting his definition of the new term asteroid, goes on to say: "if a new name must be found, why not call them by some appellation which shall, in some degree, be descriptive of, or at least consistent with, their properties? why not, for instance, call them _concentric comets_, or _planetary comets_, or _cometary planets_? or, if a single term must be found, why may we not coin such a phrase as _planetoid_ or _cometoid_?" then follows a general arraignment of herschel's methods of expression and thought, as distinguished from his powers of mere observation. this distinction, it may be said, exists only in the reviewer's mind; there was no such distinction in fact. if ever a series of observations was directed by profound and reasonable thought, it was herschel's own. "dr. herschel's passion for coining words and idioms has often struck us as a weakness wholly unworthy of him. the invention of a name is but a poor achievement for him who has discovered whole worlds. why, for instance, do we hear him talking of the _space-penetrating power_ of his instrument--a compound epithet and metaphor which he ought to have left to the poets, who, in some future age, shall acquire glory by celebrating his name. the other papers of dr. herschel, in the late volumes of the _transactions_, do not deserve such particular attention. his catalogue of 500 new nebulæ, though extremely valuable to the practical astronomer, leads to no general conclusions of importance, and abounds with the defects which are peculiar to the doctor's writings--a great prolixity and tediousness of narration--loose and often unphilosophical reflections, which give no very favorable idea of his scientific powers, however great his merit may be as an observer--above all, that idle fondness for inventing names without any manner of occasion, to which we have already alluded, and a use of novel and affected idioms. * * * * * "to the speculations of the doctor on the nature of the sun, we have many similar objections; but they are all eclipsed by the grand absurdity which he has there committed, in his hasty and erroneous theory concerning the influence of the solar spots on the price of grain. since the publication of gulliver's voyage to laputa, nothing so ridiculous has ever been offered to the world. we heartily wish the doctor had suppressed it; or, if determined to publish it, that he had detailed it in language less confident and flippant." one is almost ashamed to give space and currency to a forgotten attack, but it yields a kind of perspective; and it is instructive and perhaps useful to view herschel's labors from all sides, even from wrong and envious ones. the study of the original papers, together with a knowledge of the circumstances in which they were written, will abundantly show that herschel's ideas sprung from a profound meditation of the nature of things in themselves. what the origin of trains of thought prosecuted for years may have been we cannot say, nor could he himself have expressed it. a new path in science was to be found out, and he found it. it was not in his closet, surrounded by authorities, but under the open sky, that he meditated the construction of the heavens. as he says, "my situation permitted me not to consult large libraries; nor, indeed, was it very material; for as i intended to view the heavens myself, nature, that great volume, appeared to me to contain the best catalogue." his remarkable memoirs on the invisible and other rays of the solar spectrum were received with doubt, and with open denial by many of the scientific bodies of europe. the reviews and notices of his work in this direction were often quite beyond the bounds of a proper scientific criticism; but herschel maintained a dignified silence. the discoveries were true, the proofs were open to all, and no response was needed from him. he may have been sorely tempted to reply, but i am apt to believe that the rumors that reached him from abroad and at home did not then affect him as they might have done earlier. he was at his grand climacteric, he had passed his sixty-third year, his temper was less hasty than it had been in his youth, and his nerves had not yet received the severe strain from whose effects he suffered during the last years of his life. * * * * * we have some glimpses of his personal life in the reminiscences of him in the _diary and letters_ of madame d'arblay, who knew him well: "1786.--in the evening mr. herschel came to tea. i had once seen that very extraordinary man at mrs. de luc's, but was happy to see him again, for he has not more fame to awaken curiosity than sense and modesty to gratify it. he is perfectly unassuming, yet openly happy, and happy in the success of those studies which would render a mind less excellently formed presumptuous and arrogant. "the king has not a happier subject than this man, who owes it wholly to his majesty that he is not wretched; for such was his eagerness to quit all other pursuits to follow astronomy solely, that he was in danger of ruin, when his talents and great and uncommon genius attracted the king's patronage. he has now not only his pension, which gives him the felicity of devoting all his time to his darling study, but he is indulged in license from the king to make a telescope according to his new ideas and discoveries, that is to have no cost spared in its construction, and is wholly to be paid for by his majesty. "this seems to have made him happier even than the pension, as it enables him to put in execution all his wonderful projects, from which his expectations of future discoveries are so sanguine as to make his present existence a state of almost perfect enjoyment. mr. locke himself would be quite charmed with him. "he seems a man without a wish that has its object in the terrestrial globe. at night mr. herschel, by the king's command, came to exhibit to his majesty and the royal family the new comet lately discovered by his sister, miss herschel; and while i was playing at piquet with mrs. schwellenburg, the princess augusta came into the room and asked her if she chose to go into the garden and look at it. she declined the offer, and the princess then made it to me. i was glad to accept it for all sorts of reasons. we found him at his telescope. the comet was very small, and had nothing grand or striking in its appearance; but it is the first lady's comet, and i was very desirous to see it. mr. herschel then showed me some of his new discovered universes, with all the good humor with which he would have taken the same trouble for a brother or a sister astronomer; there is no possibility of admiring his genius more than his gentleness." "_1786, december 30th_.--this morning my dear father carried me to dr. herschel. that great and very extraordinary man received us almost with open arms. he is very fond of my father, who is one of the council of the royal society this year, as well as himself. . . . at this time of day there was nothing to see but his instruments; those, however, are curiosities sufficient. . . . i wished very much to have seen his sister, . . . but she had been up all night, and was then in bed." "_1787, september_.--dr. herschel is a delightful man; so unassuming with his great knowledge, so willing to dispense it to the ignorant, and so cheerful and easy in his general manners, that, were he no genius, it would be impossible not to remark him as a pleasing and sensible man." "_1788, october 3d_.--we returned to windsor at noon, and mrs. de luc sent me a most pressing invitation to tea and to hear a little music. two young ladies were to perform at her house in a little concert. dr. herschel was there, and accompanied them very sweetly on the violin; his new-married wife was with him, and his sister. his wife seems good-natured; she was rich, too! and astronomers are as able as other men to discern that gold can glitter as well as stars." dr. burney to madame d'arblay. "chelsea college, _september 28, 1798_. "* * * * * "i drove through slough in order to ask at dr. herschel's door when my visit would be least inconvenient to him--that night or next morning. the good soul was at dinner, but came to the door himself, to press me to alight immediately and partake of his family repast; and this he did so heartily that i could not resist. * * * * * * * "i expected (not knowing that herschel was married) only to have found miss herschel; but there was a very old lady, the mother, i believe, of mrs. herschel, who was at the head of the table herself, and a scots lady (a miss wilson, daughter of dr. wilson, of glasgow, an eminent astronomer), miss herschel, and a little boy. they rejoiced at the accident which had brought me there, and hoped i would send my carriage away and take a bed with them. they were sorry they had no stables for my horses. "we soon grew acquainted--i mean the ladies and i--and before dinner was over we seemed old friends just met after a long absence. mrs. herschel is sensible, good-humored, unpretending, and well bred; miss herschel all shyness and virgin modesty; the scots lady sensible and harmless; and the little boy entertaining, promising, and comical. herschel, you know, and everybody knows, is one of the most pleasing and well-bred natural characters of the present age, as well as the greatest astronomer. "your health was drunk after dinner (put that into your pocket), and after much social conversation and a few hearty laughs, the ladies proposed to take a walk, in order, i believe, to leave herschel and me together. we walked and talked round his great telescopes till it grew damp and dusk, then retreated into his study to philosophize. * * * * * "he made a discovery to me, which, had i known it sooner, would have overset me, and prevented my reading any part of my work.[24] he said that he had almost always had an aversion to poetry, which he regarded as the arrangement of fine words, without any useful meaning or adherence to truth; but that when truth and science were united to these fine words, he liked poetry very well." 1798, december 10. dr. burney to madame d'arblay. "herschel has been in town for short spurts, and back again two or three times, leaving mrs. herschel behind (in town) to transact law business. i had him here two whole days." the reading of the manuscript of the _poetical history of astronomy_ was continued, "and herschel was so humble as to confess that i knew more of the history of astronomy than he did, and had surprised him with the mass of information i had got together. "he thanked me for the entertainment and instruction i had given him. 'can anything be grander?' and all this before he knows a word of what i have said of himself--all his discoveries, as you may remember, being kept back for the twelfth and last book." dr. burney to madame d'arblay. "slough, _monday morning._ _july 22, 1799_, in bed at dr. herschel's, half-past five, where i can neither sleep nor lie idle. "my dear fanny:--i believe i told you on friday that i was going to finish the perusal of my astronomical verses to the great astronomer on saturday. * * * * * "after tea dr. herschel proposed that we two should retire into a quiet room in order to resume the perusal of my work, in which no progress has been made since last december. the evening was finished very cheerfully; and we went to our bowers not much out of humor with each other or the world. . . . after dinner we all agreed to go to the terrace [at windsor]--mr., mrs., and miss h., with their nice little boy, and three young ladies. here i met with almost everybody i wished and expected to see previous to the king's arrival. * * * * * "but now here comes will, and i must get up, and make myself up to go down to the perusal of my last book, entitled _herschel_. so good-morrow." "chelsea, _tuesday._ "not a moment could i get to write till now. . . . i must tell you that herschel proposed to me to go with him to the king's concert at night, he having permission to go when he chooses, his five nephews (griesbachs) making a principal part of the band. 'and,' says he, 'i know you will be welcome.'" an intimacy was gradually established between herschel and dr. burney. they saw each other often at the meetings of the royal society, and herschel frequently stayed at the doctor's house. "on the first evening herschel spent at chelsea, when i called for my argand lamp, herschel, who had not seen one of those lamps, was surprised at the great effusion of light, and immediately calculated the difference between that and a single candle, and found it sixteen to one."[25] in 1793 we find herschel as a witness for his friend james watt, in the celebrated case of watt _vs._ bull, which was tried in the court of common pleas. and from muirhead's life of watt, it appears that herschel visited watt at heathfield in 1810. a delightful picture of the old age of herschel is given by the poet campbell,[26] whose nature was fitted to perceive the beauties of a grand and simple character like herschel's: "[brighton], _september 15, 1813_. . . . "i wish you had been with me the day before yesterday, when you would have joined me, i am sure, deeply in admiring a great, simple, good old man--dr. herschel. do not think me vain, or at least put up with my vanity, in saying that i almost flatter myself i have made him my friend. i have got an invitation, and a pressing one, to go to his house; and the lady who introduced me to him, says he spoke of me as if he would really be happy to see me. . . . i spent all sunday with him and his family. his son is a prodigy in sciences, and fond of poetry, but very unassuming. . . . now, for the old astronomer himself. his simplicity, his kindness, his anecdotes, his readiness to explain--and make perfectly conspicuous too--his own sublime conceptions of the universe are indescribably charming. he is seventy-six, but fresh and stout; and there he sat, nearest the door, at his friend's house, alternately smiling at a joke, or contentedly sitting without share or notice in the conversation. any train of conversation he follows implicitly; anything you ask he labors with a sort of boyish earnestness to explain. "i was anxious to get from him as many particulars as i could about his interview with buonaparte.[27] the latter, it was reported, had astonished him by his astronomical knowledge. "'no,' he said, 'the first consul did surprise me by his quickness and versatility on all subjects; but in science he seemed to know little more than any well-educated gentleman, and of astronomy much less for instance than our own king. his general air,' he said, 'was something like affecting to know more than he did know.' he was high, and tried to be great with herschel, i suppose, without success; and 'i remarked,' said the astronomer, 'his hypocrisy in concluding the conversation on astronomy by observing how all these glorious views gave proofs of an almighty wisdom.' i asked him if he thought the system of laplace to be quite certain, with regard to the total security of the planetary system from the effects of gravitation losing its present balance? he said, no; he thought by no means that the universe was secured from the chance of sudden losses of parts. "he was convinced that there had existed a planet between _mars_ and _jupiter_, in our own system, of which the little asteroids, or planetkins, lately discovered, are indubitably fragments; and 'remember,' said he, 'that though they have discovered only four of those parts, there will be thousands--perhaps thirty thousand more--yet discovered.' this planet he believed to have been lost by explosion. "with great kindness and patience he referred me, in the course of my attempts to talk with him, to a theorem in newton's 'principles of natural philosophy' in which the time that the light takes to travel from the sun is proved with a simplicity which requires but a few steps in reasoning. in talking of some inconceivably distant bodies, he introduced the mention of this plain theorem, to remind me that the progress of light could be measured in the one case as well as the other. then, speaking of himself, he said, with a modesty of manner which quite overcame me, when taken together with the greatness of the assertion: 'i have looked _further into space than ever human being did before me_. i have observed stars, of which the light, it can be proved, must take two millions of years to reach this earth.' "i really and unfeignedly felt at this moment as if i had been conversing with a supernatural intelligence. 'nay, more,' said he, 'if those distant bodies had ceased to exist two millions of years ago, we should still see them, as the light would travel after the body was gone. . . .' these were herschel's words; and if you had heard him speak them, you would not think he was apt to tell more than the truth. "after leaving herschel i felt elevated and overcome; and have in writing to you made only this memorandum of some of the most interesting moments of my life." campbell's conscientious biographer appears to have felt that the value of this charming account of his interview with herschel was in its report of astronomical facts and opinions, and he adds a foot-note to explain that "herschel's opinion never amounted to more than _hypothesis_ having some degree of probability. sir john herschel remembers his father saying, 'if that hypothesis were true, and _if_ the planet destroyed were as large as the earth, there must have been at least thirty-thousand such fragments,' but always as an hypothesis--he was never heard to declare any degree of conviction that it was so." for us, the value of this sympathetic account of a day in herschel's life is in its conception of the simplicity, the modesty, the "boyish earnestness," the elevation of thought and speech of the old philosopher; and in the impression made on the feelings, not the mind, of the poet, then thirty-five years old. in a letter to alison, campbell reverts with great pleasure to the day spent with herschel: "sydenham, _december 12, 1813_. "my dearest alison:- * * * * * "i spent three weeks with my family at brighton, in charming weather, and was much pleased with, as well as benefited by, the place. there i met a man with whom you will stare at the idea of my being congenial, or having the vanity to think myself so--the great herschel. he is a simple, great being. . . . i once in my life looked at newton's _principia_, and attended an astronomical class at glasgow; wonderful it seemed to myself, that the great man condescended to understand my questions; to become apparently earnest in communicating to me as much information as my limited capacity and preparation for such knowledge would admit. he invited me to see him at his own abode, and so kindly that i could not believe that it was mere good breeding; but a sincere wish to see me again. i had a full day with him; he described to me his whole interview with buonaparte; said it was not true, as reported, that buonaparte understood astronomical subjects deeply, but affected more than he knew. "in speaking of his great and chief telescope, he said with an air, not of the least pride, but with a greatness and simplicity of expression that struck me with wonder, 'i have looked further into space than ever human being did before me. i have observed stars, of which the light takes _two millions_ of years to travel to this globe.' i mean to pay him a reverential visit at slough, as soon as my book is out, this winter." * * * * * in 1807 carolina herschel has this entry in her diary: "_october_ 4.--my brother came from brighton. the same night two parties from the castle came to see the comet, and during the whole month my brother had not an evening to himself. as he was then in the midst of polishing the forty-foot mirror, rest became absolutely necessary after a day spent in that most laborious work; and it has ever been my opinion that on the 14th of october his nerves received a shock of which he never got the better afterwards." in the spring of 1808 he was quite seriously ill; but in may the observing went on again. in 1809 and 1810 his principal investigations were upon physical subjects (newton's rings), and in 1811 the only long series of observations was upon the comet of that year. after 1811 the state of herschel's health required that his observations should be much less frequent. much of the time after 1811 he was absent, and his work at home consisted largely in arranging the results of his previous labors, and in computations connected with them. all through the years 1814 to 1822, herschel's health was very feeble. the severe winter of 1813-14 had told materially upon him. in 1814, however, he undertook to repolish the forty-foot mirror, but was obliged to give it over. he now found it necessary to make frequent little excursions for change of air and scene. his faithful sister remained at home, bringing order into the masses of manuscript, and copying the papers for the royal society. she was sick at heart, fearing that each time she saw her brother it would be the last. in 1818 she says: "feb. 11, i went to my brother and remained with him till the 23d. we spent our time, though not in idleness, in sorrow and sadness. he is not only unwell, but low in spirits." in 1818 (december 16), herschel went to london to have his portrait painted by artaud. while he was in london his will was made.[28] in 1819 there is a glimmer of the old-time light. in a note herschel says: "lina:--there is a great comet. i want you to assist me. come to dine and spend the day here. if you can come soon after one o'clock, we shall have time to prepare maps and telescopes. i saw its situation last night. it has a long tail. "_july 4, 1819._" this note has been carefully kept by his sister, and on it she has written: "i keep this as a relic. every line _now_ traced by the hand of my dear brother becomes a treasure to me." so the next three years passed away. sir william[29] was daily more and more feeble. he spent his time in putting his works in order, but could devote only a few moments each day to this. his sister says: "_aug. 11th_, _12th_, _13th_, and _14th_ [1822], i went as usual to spend some hours of the forenoon with my brother. "_aug. 15th._--i hastened to the spot where i was wont to find him, with the newspaper which i was to read to him. but instead i found mrs. monson, miss baldwin, and mr. bulman, from leeds, the grandson of my brother's earliest acquaintance in this country. i was informed my brother had been obliged to return to his room, whither i flew immediately. lady h. and the housekeeper were with him, administering everything which could be thought of for supporting him. i found him much irritated at not being able to grant mr. bulman's request for some token of remembrance for his father. as soon as he saw me, i was sent to the library to fetch one of his last papers and a plate of the forty-foot telescope. but for the universe i could not have looked twice at what i had snatched from the shelf, and when he faintly asked if the breaking up of the milky way was in it, i said 'yes,' and he looked content. i cannot help remembering this circumstance; it was the last time i was sent to the library on such an occasion. that the anxious care for his papers and workrooms never ended but with his life, was proved by his frequent whispered inquiries if they were locked and the key safe, of which i took care to assure him that they were, and the key in lady herschel's hands. "after half an hour's vain attempt to support himself, my brother was obliged to consent to be put to bed, leaving no hope ever to see him rise again." on the 25th of august, 1822, herschel died peacefully at the age of eighty-four years. his remains lie in the little church at upton, near windsor, where a memorial tablet has been erected by his son. the epitaph is as follows:[30] h. s. e. gulielmus herschel eques guelphicus hanoviæ natus angliam elegit patriam astronomis ætatis suæ præstantissimis merito annumeratus ut leviora sileantur inventa planetam ille extra saturni orbitam primus detexit novis artis adjumentis innixus quæ ipse excogitavit et perfecit coelorum perrupit claustra et remotiora penetrans et explorans spatia incognitos astrorum ignes astronomorum oculis et intellectui subjecit qua sedulitate qua solertia corporum et phantasmatum extra systematis nostri fines lucentium naturam indagaverit quidquid paulo audacius conjecit ingenita temperans verecundia ultro testantur hodie æquales vera esse quæ docuit pleraque siquidem certiora futuris ingeniis subsidia debitura est astronomia agnoscent forte posteri vitam utilem innocuam amabilem non minus felici laborum exitu quam virtutibus ornatam et vere eximiam morte suis et bonis omnibus deflenda nec tamen immatura clausit die xxv augusti a. d. ci[c]i[c]cccxxii ætatis vero suæ lxxxiv. footnotes: [18] bode's _jahrbuch_, 1788, p. 144. [19] zach's _monatlich correspondenz_, 1802, p. 56. [20] bode's _jahrbuch_, 1788, p. 161. [21] through sir john herschel there is preserved to us an incident of his early boyhood, which shows the nature of the training his young mind received in the household at slough. walking with his father, he asked him "what was the oldest of all things?" the father replied, after the socratic manner, "and what do you suppose is the oldest of all things?" the boy was not successful in his answers, whereon the old astronomer took up a small stone from the garden walk: "there, my child, there is the oldest of all the things that i certainly know." on another occasion the father asked his son, "what sort of things do you think are most alike?" the boy replied, "the leaves of the same tree are most like each other." "gather, then, a handful of leaves from that tree," rejoined the philosopher, "and choose two which are alike."--_monthly notices royal astronomical society_, vol. xxxii., page 123. [22] _memoir of caroline herschel_, p. 42. [23] "of late years these expectations have been more than accomplished by the discovery of no fewer than four planetary bodies, almost all in the same place; but so small that dr. herschel refuses to honor them with the name of planets, and chooses to call them asteroids, though for what reason it is not easy to determine, unless it be to deprive the discoverers of these bodies of any pretence for rating themselves as high in the list of astronomical discoverers as himself."--_history of the royal society_, by thomas thomson, p. 358. this work was published in 1812, and therefore during the lifetime of herschel. [24] _poetical history of astronomy_: this work was nearly completed, but was never published. the whole of it was read to herschel, in order that burney might have the benefit of his criticism on its technical terms. [25] _memoirs of dr. burney_, vol. iii., p. 264. [26] life and letters of thomas campbell, edited by william beattie, vol. ii., p. 234. [27] this interview must have taken place in 1802, during herschel's journey to paris. we have no other record of it. [28] the will of herschel was dated december 17th, 1818. "the personal effects were sworn under £6,000. the copyhold and other lands and tenements at upton-cum-chalvey, in the county of bucks, and at slough, he decrees to his son, with £25,000 in the 3 per cent. reduced annuities. £2,000 are given to his brother johann dietrich, and annuities of £100 each to his brother johann alexander and to his sister carolina; £20 each to his nephews and nieces, and the residue (with the exception of astronomical instruments, telescopes, observations, etc., which he declares to have given, on account of his advanced age, to his son for the purpose of continuing his studies) is left solely to lady herschel."--_gentleman's magazine_, vol. xcii., 1822, p. 650. it is not necessary to say here how nobly sir john herschel redeemed the trust confided in him. all the world knows of his survey of the southern heavens, in which he completed the review of the sky which had been begun and completed for the northern heavens by the same instruments in his father's hands. a glance at the bibliography at the end of this book will show the titles of several papers by sir john, written with the sole object of rendering his father's labors more complete. [29] he was created a knight of the royal hanoverian guelphic order in 1816, and was the first president of the royal astronomical society in 1821, his son being its first foreign secretary. [30] bode's _jahrbuch_, 1823, p. 222. chapter iv. review of the scientific labors of william herschel. in this chapter i shall endeavor to give such explanations as will enable the general reader to follow the course of discovery in each branch of astronomy and physics, regularly through the period of herschel's life, and up to the state in which he left it. a more detailed and precise account, which should appeal directly to the professional astronomer, will not be needed, since arago has already fulfilled this want in his "_analyse de la vie et des travaux de sir william herschel_," published in 1842. the few misconceptions there contained will be easily corrected by those to whom alone they are of consequence. the latter class of readers may also consult the abstracts of herschel's memoirs, which have been given in "_a subject-index and a synopsis of the scientific writings of sir william herschel_," prepared by dr. hastings and myself, and published by the smithsonian institution. an accurate sketch of the state of astronomy in england and on the continent, in the years 1780-1820, need not be given. it will be enough if we remember that of the chief observatories of europe, public and private, no one was actively devoted to such labors as were undertaken by herschel at the very beginning of his career. his observations on variable stars, indeed, were in the same line as those of pigott; flaugergues and darquier, in france, had perhaps preceded him in minute scrutiny of the sun's surface, etc.; but, even in that department of observation, he at once put an immense distance between himself and others by the rapid and extraordinary advances in the size and in the excellence of his telescopes. before his time the principal aids to observation were the gregorian and newtonian telescopes of short, and the small achromatics of dollond.[31] we have seen, in what goes before, how his patient zeal had succeeded in improving upon these. there was no delay, and no rest. steadily the art of making reflectors was urged forward, until he had finally in his hands the forty-foot telescope. it must be admitted that this was the limit to which the manufacture of powerful telescopes could be pushed in his generation. the optical and mechanical difficulties which prevented a farther advance required time for their solution; and, indeed, some of these difficulties are scarcely solved at this day. it may fairly be said that no reflector larger than three feet in aperture has yet realized our expectations. _the improvement of telescopes and optical apparatus._ it will be of interest to give in this place some connected account of the large forty-foot reflector, of four feet aperture, made by herschel. its history extends from 1785 to 1811. its manufacture was considered by his cotemporaries as his greatest triumph. as a machine, it was extremely ingenious in all its parts, as may be seen from the elaborate description and plates of it published in the _philosophical transactions_ for 1795. one of its mirrors certainly had good definition, for, by means of it, the two small satellites of _saturn_ (_mimas_ and _enceladus_) were discovered, and these discoveries alone would make it famous. perhaps more was expected of it by the public in general than it absolutely performed. its merits were after a while decried, and herschel even felt obliged to state why he did not always employ it in his observations. his reasons were perfectly valid, and such as any one may understand. the time required to get so large a machine into working order was a serious tax; it required more assistants than his twenty-foot telescope, and he says, "i have made it a rule never to employ a larger telescope when a smaller will answer the purpose." it still remains as a remarkable feat of engineering and an example of great optical and mechanical skill. it led the way to the large reflectors of lord rosse, some sixty years later, and several of the forty-foot telescopes of the present day even have done less useful work. its great feat, however, was to have added two satellites to the solar system. from the published accounts of it the following is taken: "when i resided at bath i had long been acquainted with the theory of optics and mechanics, and wanted only that experience so necessary in the practical part of these sciences. this i acquired by degrees at that place, where in my leisure hours, by way of amusement, i made several two-foot, five-foot, seven-foot, ten-foot, and twenty-foot newtonian telescopes, beside others, of the gregorian form, of eight, twelve, and eighteen inches, and two, three, five, and ten feet focal length. in this way i made not less than two hundred seven-foot, one hundred and fifty ten-foot, and about eighty twenty-foot mirrors, not to mention the gregorian telescopes.[32] "the number of stands i invented for these telescopes it would not be easy to assign. . . . in 1781 i began to construct a thirty-foot aërial reflector, and having made a stand for it, i cast the mirror thirty-six inches in diameter. this was cracked in cooling. i cast it a second time, and the furnace i had built in my house broke." soon after, the georgian planet was discovered, and this interrupted the work for a time. "in the year 1783 i finished a very good twenty-foot reflector with a large aperture, and mounted it upon the plan of my present telescope. after two years' observation with it, the great advantage of such apertures appeared so clearly to me that i recurred to my former intention of increasing them still further; and being now sufficiently provided with experience in the work which i wished to undertake, the president of the royal society, who is always ready to promote useful undertakings, had the goodness to lay my design before the king. his majesty was graciously pleased to approve of it, and with his usual liberality to support it with his royal bounty. "in consequence of this arrangement i began to construct the forty-foot telescope about the latter end of 1785.[33] the woodwork of the stand and machines for giving the required motions to the instrument were immediately put in hand. in the whole of the apparatus none but common workmen were employed, for i made drawings of every part of it, by which it was easy to execute the work, as i constantly inspected and directed every person's labor; though sometimes there were not less than forty different workmen employed at the same time. while the stand of the telescope was preparing, i also began the construction of the great mirror, of which i inspected the casting, grinding, and polishing, and the work was in this manner carried on with no other interruption than that occasioned by the removal of all the apparatus and materials from where i then lived, to my present situation at slough. "here, soon after my arrival, i began to lay the foundation upon which by degrees the whole structure was raised as it now stands, and the speculum being highly polished and put into the tube, i had the first view through it on february 19, 1787. i do not, however, date the completing of the instrument till much later. for the first speculum, by a mismanagement of the person who cast it, came out thinner on the centre of the back than was intended, and on account of its weakness would not permit a good figure to be given to it. "a second mirror was cast january 26, 1788, but it cracked in cooling. february 16 we recast it, and it proved to be of a proper degree of strength. october 24 it was brought to a pretty good figure and polish, and i observed the planet _saturn_ with it. but not being satisfied, i continued to work upon it till august 27, 1789, when it was tried upon the fixed stars, and i found it to give a pretty sharp image. large stars were a little affected with scattered light, owing to many remaining scratches on the mirror. august the 28th, 1789, having brought the telescope to the parallel of _saturn_, i discovered a _sixth_ satellite of that planet, and also saw the spots upon _saturn_ better than i had ever seen them before, so that i may date the finishing of the forty-foot telescope from that time." another satellite of _saturn_ was discovered with the forty-foot on the 17th of september (1789). it was used for various observations so late as 1811. on january 19, of that year, herschel observed the nebula of _orion_ with it. this was one of his last observations. the final disposition of the telescope is told in the following extract from a letter of sir john herschel's to mr. weld, secretary of the royal society: "collingwood, _march 13, 1847_. . . . "in reply to your queries, respecting the forty-foot reflecting telescope constructed by my father, i have to state that king george iii. munificently defrayed the _entire_ cost of that instrument (including, of course, all preparatory cost in the nature of construction of tools, and of the apparatus for casting, grinding, and figuring the reflectors, of which two were constructed), at a total cost of £4,000. the woodwork of the telescope being so far decayed as to be dangerous, in the year 1839 i pulled it down, and piers were erected on which the tube was placed, _that_ being of iron and so well preserved, that, although not more than one-twentieth of an inch thick, when in the horizontal position it sustained within it all my family, and continues to sustain inclosed within it, to this day, not only the heavier of the two reflectors, but also all the more important portions of the machinery. . . . the mirror and the rest of the polishing apparatus are on the premises. the iron grinding tools and polishers are placed underneath the tube, let into the ground, and level with the surface of the gravelled area in which it stands.". . . the closing of the tube was done with appropriate ceremony on new-year's-day, 1840, when, after a procession through it by the family at slough, a poem, written by sir john, was read, the machinery put into its present position, and the tube sealed. the memoir on the forty-foot telescope shows throughout that herschel's prime object was not the making of the telescope itself, but that his mind was constantly directed towards the uses to which it was to be put--towards the questions which he wished it to answer. again and again, in his various papers, he returns to the question of the _limit of vision_. as bessel has said: "the naked eye has its limit of vision in the stars of the sixth magnitude. the light of fainter stars than these does not affect the retina enough for them to be seen. a very small telescope penetrates to smaller, and, in general, without doubt, to more distant stars. a more powerful one penetrates deeper into space, and as its power is increased, so the boundaries of the visible universe are widened, and the number of stars increased to millions and millions. whoever has followed the history of the series of herschel's telescopes will have observed this. but herschel was not content with the bare fact, but strove ever to know _how far_ a telescope of a certain construction and size could penetrate, compared with the naked and unassisted eye. these investigations were never for the discovery of new facts concerning the working of his instruments; it was for the knowledge of the distribution of the fixed stars in space itself that he strove. . . . herschel's instruments were designed to aid vision to the last extent. they were only secondarily for the taking of measures. his efforts were not for a knowledge of the _motions_, but of the _constitution_ and _construction_ of the heavenly bodies." besides the stands for his telescopes, which were both ingenious and convenient, herschel devised many forms of apparatus for facilitating the art of observation. his micrometers for measuring position angles, his lamp micrometer, the method of limiting apertures, and the methods he used for viewing the sun may be mentioned among these. points in practical astronomy are considered all through the years of observation. a reference to his original papers will show how numerous, how varied, and how valuable these are. i cannot forbear quoting here the account of a precaution observed during his examination of the belts on _saturn_ (1794). it is the most striking example of how fully herschel realized that the eye of the observer is a material part of the optical apparatus of astronomy. simple as this principle may appear, it was an absolute novelty in his day. in making these observations, he says: "i took care to bend my head so as to receive the picture of the belt in the same direction as i did formerly. this was a precaution that occurred to me, as there was a possibility that the vertical diameter of the retina might be more or less sensitive than the horizontal one." astronomers will recognize in this the first suggestion of the processes which have led to important results in the hands of dr. otto struve and others in the comparison of the measures of double stars by different observers, each of whom has a personal habit of observation, which, if not corrected, may affect his results in the way which herschel was striving to avoid. _researches on the relative brightness of the stars: variable stars._ no research of herschel's was more laborious than the elaborate classification of the stars according to their comparative brightness, which he executed during the years 1796 to 1799. it was directly in the line of his main work--to find out the construction of the heavens. his first paper had been upon the variable star _mira ceti_. here was a sun, shining by its native brightness, which waxed and waned like the moon itself. this star is periodic. it is for a long period invisible to the unassisted eye. then it can just be seen, and increases in brightness for a little over a month, and attains a maximum brilliancy. from this it decreases for nearly three months, and after becoming invisible, remains so for five or six months. its whole period is about 333 days. are all other stars constant in brightness? the example of _mira ceti_ and of other known variables makes this at least doubtful. but the sun itself may vary for all that we know. it is a simple star like the rest. this question of variability in general is an important one, then. it can only be tested by making accurate catalogues of the relative brilliance of stars at various times, and by comparing these. no such general catalogue existed before herschel's time, and led by the discrepancies in isolated cases, which he found between his own estimates and those of his predecessors, he made from observation a series of four catalogues, in which were set down the order of sequence of the stars of each constellation. the method adopted by herschel was perfectly simple in principle, though most laborious in practice. suppose any number of stars, a, b, c, d, e, . . . etc., near enough to each other to be well compared. the process consists simply in writing down the names of the stars, a, b, c, etc., in the order of their relative brightness. thus if for a group of eight stars we have found at one epoch a, b, c, d, e, f, g, h, and if at another time the order was a, b, c, d, f, e, g, h, symptoms of variability are pointed out. repeated observations, where the same star is found in different sequences, will decide the question. thus, for the stars visible to the naked eye, we know exactly the state of the sky in herschel's day, now nearly a century ago. any material change cannot escape us. these catalogues have been singularly overlooked by the observers of our generation who have followed this branch of observation, and it was not till 1876 that they received proper attention and a suitable reduction (at the hands of mr. c. s. pierce). we owe to herschel the first trustworthy account of the stars visible to the naked eye, and since the date of his labors (about 1800) we have similar views published by argelander (1839), heis (1848), argelander and schönfeld (1857), gould (1860 and 1872), and houzeau (1875). thus his labors have been well followed up. in the prosecution of this work herschel found stars whose light was progressively diminishing, others which regularly increased, one star whose light periodically varies (_[alpha] herculis_), and at least one star (55 _herculis_) which has utterly disappeared. on october 10, 1781, and april 11, 1782, he observed this latter star, but in may, 1791, it had totally vanished. there was no trace remaining. the discovery of the variability of _[alpha] herculis_ was a more important one than would at first sight appear. up to that time the only variable stars known were seven in number. their periods were four hundred and ninety-four, four hundred and four, three hundred and thirty-four, seven, six, five, and three days. these periods seemed to fall into two groups, one of from three hundred to five hundred days, the other comparatively much shorter, of three to seven days. _[alpha] herculis_ came to occupy the middle place between these groups, its period being about sixty days. the cause of these strange and regular variations of brightness was supposed by herschel to be the rotation of the star bodily on an axis, by which revolution different parts of its surface, of different brilliancy, were successively and periodically presented to us. this explanation it might have been difficult to receive, when the periods of the known variables were so markedly various in length. his own discovery came to bridge over the interval, and quite confirmed him in his belief. he returned to the subject of the revolution of stars about their axes again and again, and connected it with the revolution of satellites. he found that the satellites of _jupiter_ and one of _saturn's_ periodically changed in brightness, and by quite simple means showed that their periods of rotation were at least approximately the same as their periods of revolution about their primaries. in this case, as in every other, he considered a discovery in each and every one of its possible bearings. there are no instances where he has singularly overlooked the consequences of his observations. _researches on double stars._ the double stars were the subject of herschel's earliest and of his latest papers. in 1782 he published his "_catalogue of double stars_," and his last published memoir (1822) was on the same subject. the question of determining the parallax of stars first brought herschel to the discovery of double stars. if two stars, a and b, appear very close together, and if, in reality, the star b is very many times more distant from the earth than a, although seen along the same line of sight, then the revolution of the earth in its orbit will produce changes in the relative situation of a and b, and, in fact, b will describe a small orbit about a, due to this revolution. this idea had been proposed by galileo, and measures on this plan had been made by long, with negative results. but herschel, in reviewing their work, declares that the stars chosen by long were not suitable to the purpose. it is necessary, among other things, to the success of this method, that it should be certain that the star b is really very much more distant than the star a. the only general test of the distance of stars is their brilliancy, and herschel decided to use only stars for this research which had two components very greatly different in brightness. a must be very bright (and presumably near to us), and b must be very close to a, and very faint (and thus, presumably, very distant). it was in the search for such pairs of stars that the _catalogue of double stars_ (1782) was formed. herschel's first idea of a double star made such pairs as he found, to consist of two stars _accidentally_ near to each other. a was near to us, and appeared projected in a certain place on the celestial sphere. b was many times more distant, but, by chance, was seen along the same line, and made with a an _optical_ double. if the two stars were at the same distance from the earth, if they made part of the same physical system, if one revolved around the other, then this method of gaining a knowledge of their distance failed. even in his first memoir on the subject, a surmise that this latter state might occur in some cases, was expressed by herschel. the notes on some of the pairs declare that a motion of one of them was suspected. but this motion might be truly orbital--of one star about the other as a centre--or it might simply be that one star was moving by its own _proper_ motion, and leaving the other behind. it was best to wait and see. the first catalogue of double stars contained two hundred and three instances of such associations. these were observed from time to time, and new pairs discovered. the paper of michell, "an inquiry into the probable parallax and magnitude of the fixed stars, from the quantity of light which they afford, and the particular circumstances of their situation" (1767), was read and pondered. by 1802 herschel had become certain that there existed in the heavens real pairs of stars, both at the same distance from the earth, which were physically connected with each other. the arguments of michell have been applied by bessel to the case of one of herschel's double stars, in much the same order in which the argument ran in herschel's own mind, as follows: the star _castor_ (_[alpha] geminorum_) is a double star, where a is of the second, and b of the fourth, magnitude. to the naked eye these two appear as one star. with a telescope this is seen to be two stars, some 5" apart. in the whole sky there are not above fifty such stars as the brighter of the two, and about four hundred of the brilliancy of b. these fifty and four hundred stars are scattered over the vault of heaven, almost at random. no law has yet been traced by which we can say that here or here there shall be a bright star like a, or a fainter one like b. in general the distribution appears to be fortuitous. how then can we account for one of the four hundred stars like b placed so close to one of the fifty like a? the chances are over four hundred thousand to one that the association in position is not accidental. this argument becomes overwhelming when the same association is found in many other cases. there were two hundred and three doubles in the catalogue of 1782 alone, and many thousands are now known. by a process like this, herschel reached his grand discovery of true binary systems, where one sun revolves about another. for he saw that if the two stars are near together in space, they could not stand still in face of each other, but that they must revolve in true orbits. here was the discovery which came to take the place of the detection of the parallaxes of the fixed stars. he had failed in one research, but he was led to grand conclusions. was the force that these distant pairs of suns obeyed, the force of gravitation? this he could not settle, but his successors have done so. it was not till about 1827 that savary, of the paris observatory, showed that one of herschel's doubles was subjected to the law of gravitation, and thus extended the power of this law from our system to the universe at large. herschel himself lived to see some of his double stars perform half a revolution. of herschel's discoveries, arago thinks this has "le plus d'avenir." it may well be so. the laws which govern our solar system have been extended, through his researches, to regions of unknown distance. the binary stars will afford the largest field for research into the laws which govern them, and together with the clusters and groups, they will give a firm basis by which to study the distribution of stars in general, since here we have the great advantage of knowing, if not the real distance of the two stars from the earth, at least that this distance is alike for both. _researches on planets and satellites._ after herschel's first publication on the mountains of the moon (1780), our satellite appears to have occupied him but little. the observation of volcanoes (1787) and of a lunar eclipse are his only published ones. the planets _mercury_, _venus_, _mars_, and _jupiter_, although they were often studied, were not the subjects of his more important memoirs. the planet _saturn_, on the contrary, seems never to have been lost sight of from the time of his first view of it in 1772. the field of discovery always appears to be completely occupied until the advent of a great man, who, even by his way of putting old and familiar facts, shows the paths along which discoveries must come, if at all. this faculty comes from profound reflection on the nature of the subject itself, from a sort of transmuting power which changes the words of the books into the things of reality. herschel's paper on _saturn_, in 1790, is an admirable example of this. herschel's observations on _saturn_ began in 1772. from 1790 to 1808 he published six memoirs on the figure, the ring, and the satellites of this planet. the spheroidal shape of the ball was first discovered by him, and we owe much of our certain knowledge of the constitution of the rings to his work. the sixth and seventh satellites, _mimas_ and _enceladus_, were discovered by him in 1789. the periods of rotation of the ball and of the ring were also fixed. in his conclusions as to the real figure of the rings, there is a degree of scientific caution which is truly remarkable, and which to-day seems almost excessive. in his paper of 1792, herschel shows that the most distant satellite of _saturn_--_japetus_--turns once on its axis in each revolution about its primary, just as our moon does. he says of this: "i cannot help reflecting with some pleasure on the discovery of an analogy which shows that a certain uniform plan is carried on among the secondary planets of our solar system; and we may conjecture that probably most of the satellites are governed by the same law; especially if it be founded on such a construction of their figure as makes them more ponderous towards their primary planets." i believe the last suggestion to have been the first statement of the possible arrangement of matter in satellites, which was afterwards so forcibly maintained by hansen in his theory of the moon. hansen's researches show the consequences of such an arrangement, although they do not prove its existence. it should be recorded that the explanation which is to-day received of the belts and bands upon _jupiter_, is, i believe, first found in herschel's memoir on _venus_ (1793). his memoir of 1797, on the changeable brightness of the satellites of _jupiter_, has already been referred to. the times of the rotation of the satellites on their axes was first determined by herschel from these observations, which also contain accounts of the curious, and as yet unexplained, phenomena attending their appearances on the disc of the planet. herschel discovered in january, 1787, the two brighter satellites of _uranus_, now called _oberon_ and _titania_. they are among the faintest objects in the solar system. a later discussion of all his observations led him to the belief that there were four more, and he gives his observations and computations in full. he says that of the existence of additional satellites he has no doubt. of these four, three were exterior to the most distant satellite _oberon_, the other was "interior" to _titania_. it was not until 1834 that even _oberon_ and _titania_ were again observed (by sir john herschel) with a telescope of twenty feet, similar to that which had discovered them, and not until 1847 was the true state of this system known, when mr. lassell discovered _ariel_ and _umbriel_, two satellites interior to _titania_, neither of which was herschel's "interior" satellite. in 1848 and later years mr. lassell, by the aid of telescopes constructed by himself, fully settled the fact that only four satellites of this planet existed. in 1874 i examined the observations of herschel on his supposed "interior" satellite, thinking that it might be possible that among the very few glimpses of it which he recorded, some might have belonged to _ariel_ and some to _umbriel_, and that by combining rare and almost accidental observations of two satellites which really existed, he had come to announce the existence of an "interior" satellite which had no existence in fact. such i believe to be the case. in 1801, april 17, herschel describes an interior satellite in the position angle 189°, distant 18" from the planet. at that instant _umbriel_, one of mr. lassell's satellites, was in the position 191°, and distant 21" from _uranus_, in the most favorable position for seeing it. the observation of 1794, march 27, _may_ belong to _ariel_. at the best the investigation is of passing interest only, and has nothing to do with the question of the discovery of the satellites. herschel discovered the two brighter ones, and it was only sixty years later that they were properly re-observed by mr. lassell, who has the great honor of having added as many more, and who first settled the vexed question of satellites _exterior_ to _oberon_, and this with a reflecting telescope made by himself, which is unequalled by any other of its dimensions. _researches on the nature of the sun._ in the introduction to his paper on the _nature and construction of the sun and fixed stars_ (1795), herschel recounts what was known of the nature of the sun at that time. newton had shown that it was the centre of the system; galileo and his successors had determined its rotation, the place of its equator, its real diameter, magnitude, density, distance, and the force of gravity on its surface. he says: "i should not wonder if, considering all this, we were induced to think that nothing remained to be added; and yet we are still very ignorant in regard to the internal construction of the sun." "the spots have been supposed to be solid bodies, the smoke of volcanoes, the scum floating on an ocean of fluid matter, clouds, opaque masses, and to be many other things." "the sun itself has been called a globe of fire, though, perhaps, metaphorically." "it is time now to profit by the observations we are in possession of. i have availed myself of the labors of preceding astronomers, but have been induced thereto by my own actual observation of the solar phenomena." herschel then refers to the theories advanced by his friend, prof. wilson, of glasgow, in 1774. wilson maintained that the spots were depressions below the sun's atmosphere, vast hollows as it were, at the bases of which the true surface of the sun could be seen. the essence of his theory was the existence of two different kinds of matter in the sun: one solid and non-luminous--the nucleus--the other gaseous and incandescent--the atmosphere. vacant places in the atmosphere, however caused, would show the black surface of the solid mass below. these were the spots. no explanation could be given of the _faculæ_, bright streaks, which appear on the sun's surface from time to time; but his theory accounted for the existence of the black _nuclei_ of the spots, and for the existence of the _penumbræ_ about these. the penumbra of a spot was formed by the thinner parts of the atmosphere about the vacancy which surrounded the nucleus. this theory of wilson's was adopted by herschel as a basis for his own, and he brought numerous observations to confirm it, in the modified shape which he gave to it. according to herschel, the sun consisted of three essentially different parts. first, there was a solid nucleus, non-luminous, cool, and even capable of being inhabited. second, above this was an atmosphere proper; and, lastly, outside of this was a layer in which floated the clouds, or bodies which gave to the solar surface its intense brilliancy: "according to my theory, a dark spot in the sun is a place in its atmosphere which happens to be free from luminous decompositions" above it. the two atmospheric layers, which will be of varying thickness about a spot, will account for all the shades of darkness seen in the penumbra. ascending currents from the solar surface will elevate certain regions, and may increase the solar activity near by, and will thus give rise to faculæ, which herschel shows to be elevated above the general surface. it will not be necessary to give a further account of this theory. the data in the possession of the modern theorist is a thousand-fold that to be derived from herschel's observations, and, while the subject of the internal construction of the sun is to-day unsettled, we know that many important, even fundamental, portions of his theory are untenable. a remark of his should be recorded, however, as it has played a great part in such theories: "that the emission of light must waste the sun, is not a difficulty that can be opposed to our hypothesis. many of the operations of nature are carried on in her great laboratory which we cannot comprehend. perhaps the many telescopic comets may restore to the sun what is lost by the emission of light." arguments in favor of the habitability of both sun and moon are contained in this paper; but they rest more on a metaphysical than a scientific basis, and are to-day justly forgotten. _researches on the motion of the sun and of the solar system in space._ in 1782 herschel writes, in regard to some of his discoveries of double stars: "these may serve another very important end. i will just mention it, though it is foreign to my present purpose. several stars of the first magnitude have been observed or suspected to have a proper motion; hence we may surmise that our sun, with all its planets and comets, may also have a motion towards some particular point of the heavens. . . . if this surmise should have any foundation, it will show itself in a series of some years in a kind of systematical parallax, or change, due to the motion of the whole solar system." in 1783 he published his paper _on the proper motion of the solar system_, which contained the proofs of his surmises of a year before. that certain of the stars had in fact a _proper_ motion had been well established by the astronomers of the eighteenth century. after all allowances had been made for the effects of precession and other displacements of a star's position which were produced by motions of the earth, it was found that there were still small outstanding differences which must be due to the motion of the star itself--its proper motion. the quantity of this motion was not well known for any star when herschel's researches began. before they were concluded, however, maskelyne had deduced the proper motions of thirty-six stars--the fundamental stars, so called--which included in their number _sirius_, _procyon_, _arcturus_, and generally the brightest stars. it is _à priori_ evident that stars, in general, must have proper motions, when once we admit the universality of gravitation. that any fixed star should be entirely at rest would require that the attractions on all sides of it should be exactly balanced. any change in the position of this star would break up this balance, and thus, in general, it follows that stars must be in motion, since all of them cannot occupy such a critical position as has to be assumed. if but one fixed star is in motion, this affects all the rest, and we cannot doubt but that every star, our sun included, is in motion by an amount which varies from small to great. if the sun alone had a motion, and the other stars were at rest, the consequence of this would be that all the fixed stars would appear to be retreating _en masse_ from that point in the sky towards which we were moving. those nearest us would move more rapidly, those more distant less so. and in the same way, the stars from which the solar system was receding would seem to be approaching each other. if the stars, instead of being quite at rest, as just supposed, had motions proper to themselves, then we should have a double complexity. they would still appear to an observer in the solar system to have motions, and part of these motions would be truly proper to the stars, and part would be due to the advance of the sun itself in space. observations can show us only the _resultant_ of these two motions. it is for reasoning to separate this resultant into its two components. at first the question is to determine whether the results of observation indicate any solar motion at all. if there is none, the proper motions of stars will be directed along all possible lines. if the sun does truly move, then there will be a general agreement in the resultant motions of the stars near the ends of the line along which it moves, while those at the sides, so to speak, will show comparatively less systematic effect. it is as if one were riding in the rear of a railway train and watching the rails over which it has just passed. as we recede from any point, the rails at that point seem to come nearer and nearer together. if we were passing through a forest, we should see the trunks of the trees from which we were going apparently come nearer and nearer together, while those on the sides of us would remain at their constant distance, and those in front would grow further and further apart. these phenomena, which occur in a case where we are sensible of our own motion, serve to show how we may deduce a motion, otherwise unknown, from the appearances which are presented by the stars in space. in this way, acting upon suggestions which had been thrown out previously to his own time by lambert, mayer, and bradley, herschel demonstrated that the sun, together with all its system, was moving through space in an unknown and majestic orbit of its own. the centre round which this motion is directed cannot yet be assigned. we can only know the point in the heavens towards which our course is directed--"the apex of solar motion." by a study of the proper motions assigned by maskelyne to the brighter stars, herschel was able to define the position of the solar apex with an astonishing degree of accuracy. his calculations have been several times repeated with the advantage of modern analytical methods, and of the hundred-fold material now at our disposition, but nothing essential has been added to his results of 1805, which were based upon such scanty data; and his paper of 1782 contains the announcement of the discovery itself. his second paper on the _direction_ and _velocity_ of the solar system (1805) is the best example that can possibly be given of his marvellous skill in reaching the heart of a matter, and it may be the one in which his philosophical powers appear in their highest exercise. for sustained reflection and high philosophic thought it is to be ranked with the researches of newton in the _principia_. _researches on the construction of the heavens._ herschel's papers on the construction of the heavens, as he named it, extended over his whole scientific life. by this he specially means the method according to which the stars, the clusters, the nebulæ, are spread through the regions of space, the causes that have led to this distribution, and the laws to which it is subjected. no single astronomical fact is unimportant in the light which it may throw on the scheme of the whole, and each fact is to be considered in this light. as an instance: his discovery of the variable star _[alpha] herculis_, which has a period of sixty days, was valuable in itself as adding one more to the number of those strange suns whose light is now brighter, now fainter, in a regular and periodic order. but the chief value of the discovery was that now we had an instance of a periodic star which went through all its phases in sixty days, and connected, as it were, the stars of short periods (three to seven days) with those of very long ones (three hundred to five hundred days), which two groups had, until then, been the only ones known. in the same way all his researches on the parallaxes of stars were not alone for the discovery of the distance of any one or two single stars, but to gain a unit of celestial measure, by means of which the depths of space might be sounded. astronomy in herschel's day considered the bodies of the solar system as separated from each other by distances, and as filling a cubical space. the ideas of near and far, of up and down, were preserved, in regard to them, by common astronomical terms. but the vast number of stars seemed to be thought of, as they appear in fact to exist, lying on the surface of a hollow sphere. the immediate followers of bradley used these fixed stars as points of reference by which the motions within the solar system could be determined, or, like lacaille and lalande, gathered those immense catalogues of their positions which are so indispensable to the science. michell and herschel alone, in england, occupied their thoughts with the nature and construction of the heavens--the one in his study, the other through observation.[34] they were concerned with all three of the dimensions of space. in his memoir of 1784, herschel says: "hitherto the sidereal heavens have, not inadequately for the purpose designed, been represented by the concave surface of a sphere, in the centre of which the eye of an observer might be supposed to be placed. "it is true the various magnitudes of the fixed stars even then plainly suggested to us, and would have better suited, the idea of an expanded firmament of three dimensions; but the observations upon which i am now going to enter still farther illustrate and enforce the necessity of considering the heavens in this point of view. in future, therefore, we shall look upon those regions into which we may now penetrate by means of such large telescopes, as a naturalist regards a rich extent of ground or chain of mountains containing strata variously inclined and directed, as well as consisting of very different materials. the surface of a globe or map, therefore, will but ill delineate the interior parts of the heavens." herschel's method of study was founded on a mode of observation which he called _star-gauging_. it consisted in pointing a powerful telescope toward various parts of the heavens, and ascertaining by actual count how thick the stars were in each region. his twenty-foot reflector was provided with such an eye-piece that, in looking into it, he saw a portion of the heavens about 15' in diameter. a circle of this size on the celestial sphere has about one quarter the apparent surface of the sun, or of the full moon. on pointing the telescope in any direction, a greater or less number of stars were visible. these were counted, and the direction in which the telescope pointed was noted. gauges of this kind were made in all parts of the sky, and the results were tabulated in the order of right ascension. the following is an extract from the gauges, and gives the average number of stars in each field at the points noted in right ascension and north polar distance: --------------------------------------------------------- | n. p. d. || | n. p. d. r. a. | 78° to 80°. || r. a. | 92° to 94°. | no. of stars. || | no. of stars. ------------|-----------------||-----------|------------- h. m. | || h. m. | 11 6 | 3.1 || 15 10 | 9.4 12 31 | 3.4 || 15 22 | 10.6 12 44 | 4.6 || 15 47 | 10.6 12 49 | 3.9 || 16 8 | 12.1 13 5 | 3.8 || 16 25 | 13.6 14 30 | 3.6 || 16 37 | 18.6 ---------------------------------------------------------in this small table, it is plain that a different law of clustering or of distribution obtains in the two regions. such differences are still more marked, if we compare the extreme cases found by herschel, as r. a. = 19h 41m, n. p. d. = 74° 33', number of stars per field = 588; and r. a. = 16h 10m, n. p. d. = 113° 4', number of stars = 1.1. the number of stars in certain portions is very great. for example, in the milky way, near _orion_, six fields of view promiscuously taken gave 110, 60, 70, 90, 70, and 74 stars each, or a mean of 79 stars per field. the most vacant space in this neighborhood gave 60 stars. so that as herschel's sweeps were two degrees wide in declination, in one hour (15°) there would pass through the field of his telescope 40,000 or more stars. in some of the sweeps this number was as great as 116,000 stars in a quarter of an hour. when herschel first applied his telescope to the milky way, he believed that it completely resolved the whole whitish appearance into small stars. this conclusion he subsequently modified. he says: "it is very probable that the great stratum called the milky way is that in which the sun is placed, though perhaps not in the very centre of its thickness. "we gather this from the appearance of the galaxy, which seems to encompass the whole heavens, as it certainly must do if the sun is within it. for, suppose a number of stars arranged between two parallel planes, indefinitely extended every way, but at a given considerable distance from each other; and calling this a sidereal stratum, an eye placed somewhere within it will see all the stars in the direction of the planes of the stratum projected into a great circle, which will appear lucid on account of the accumulation of the stars, while the rest of the heavens, at the sides, will only seem to be scattered over with constellations, more or less crowded according to the distance of the planes, or number of stars contained in the thickness or sides of the stratum. "if the eye were placed somewhere without the stratum, at no very great distance, the appearance of the stars within it would assume the form of one of the smaller circles of the sphere, which would be more or less contracted according to the distance of the eye; and, if this distance were exceedingly increased, the whole stratum might at last be drawn together into a lucid spot of any shape, according to the length, breadth, and height of the stratum. "suppose that a smaller stratum should branch out from the former in a certain direction, and that it also is contained between two parallel planes, so that the eye is contained within the great stratum somewhere before the separation, and not far from the place where the strata are still united. then this second stratum will not be projected into a bright circle like the former, but it will be seen as a lucid branch proceeding from the first, and returning into it again at a distance less than a semicircle. if the bounding surfaces are not parallel planes, but irregularly curved surfaces, analogous appearances must result." the milky way, as we see it, presents the aspect which has been just accounted for, in its general appearance of a girdle around the heavens and in its bifurcation at a certain point, and herschel's explanation of this appearance, as just given, has never been seriously questioned. one doubtful point remains: are the stars scattered all through space? or are they near its bounding planes, or clustered in any way within this space so as to produce the same result to the eye as if uniformly distributed? herschel assumed that they were nearly equably arranged all through the space in question. he only examined one other arrangement, _viz._, that of a ring of stars surrounding the sun, and he pronounced against such an arrangement, for the reason that there is absolutely nothing in the size or brilliancy of the sun to cause us to suppose it to be the centre of such a gigantic system. no reason, except its importance to us personally, can be alleged for such a supposition. every star will have its own appearance of a galaxy or milky way, which will vary according to the situation of the star. such an explanation will account for the general appearances of the milky way and of the rest of the sky, supposing the stars equally or nearly equally distributed in space. on this supposition, the system must be deeper where the stars appear most numerous. herschel endeavored, in his early memoirs, to explain this inequality of distribution on the fundamental assumption that the stars were nearly equably distributed in space. if they were so distributed, then the number of stars visible in any gauge would show the thickness of the stellar system in the direction in which the telescope was pointed. at each pointing, the field of view of the instrument includes all the visible stars situated within a cone, having its vortex at the observer's eye, and its base at the very limits of the system, the angle of the cone (at the eye) being 15'. then the cubes of the perpendiculars let fall from the eye, on the plane of the bases of the various visual cones, are proportional to the solid contents of the cones themselves, or, as the stars are supposed equally scattered within all the cones, the cube roots of the numbers of stars in each of the fields express the relative lengths of the perpendiculars. a _section_ of the sidereal system along any great circle can be constructed from the data furnished by the gauges in the following way: the solar system is within the mass of stars. from this point lines are drawn along the different directions in which the gauging telescope was pointed. on these lines are laid off lengths proportional to the cube roots of the number of stars in each gauge. the irregular line joining the terminal points will be approximately the bounding curve of the stellar system in the great circle chosen. within this line the space is nearly uniformly filled with stars. without it is empty space. a similar section can be constructed in any other great circle, and a combination of all such would give a representation of the shape of our stellar system. the more numerous and careful the observations, the more elaborate the representation, and the 863 gauges of herschel are sufficient to mark out with great precision the main features of the milky way, and even to indicate some of its chief irregularities. on the fundamental assumption of herschel (equable distribution), no other conclusion can be drawn from his statistics but the one laid down by him. this assumption he subsequently modified in some degree, and was led to regard his gauges as indicating not so much the _depth of the system_ in any direction, as the _clustering power or tendency_ of the stars in those special regions. it is clear that if in any given part of the sky, where, on the average, there are ten stars (say) to a field, we should find a certain small portion having 100 or more to a field, then, on herschel's first hypothesis, rigorously interpreted, it would be necessary to suppose a spike-shaped protuberance directed from the earth, in order to explain the increased number of stars. if many such places could be found, then the probability is great that this explanation is wrong. we should more rationally suppose some real inequality of star distribution here. it is, in fact, in just such details that the method of herschel breaks down, and a careful examination of his system leads to the belief that it must be greatly modified to cover all the known facts, while it undoubtedly has, in the main, a strong basis. the stars are certainly not uniformly distributed, and any general theory of the sidereal system must take into account the varied tendency to aggregation in various parts of the sky. in 1817, herschel published an important memoir on the same subject, in which his first method was largely modified, though not abandoned. its fundamental principle was stated by him as follows: "it is evident that we cannot mean to affirm that the stars of the fifth, sixth, and seventh magnitudes are really smaller than those of the first, second, or third, and that we must ascribe the cause of the difference in the apparent magnitudes of the stars to a difference in their relative distances from us. on account of the great number of stars in each class, we must also allow that the stars of each succeeding magnitude, beginning with the first, are, one with another, further from us than those of the magnitude immediately preceding. the relative magnitudes give only relative distances, and can afford no information as to the real distances at which the stars are placed. "a standard of reference for the arrangement of the stars may be had by comparing their distribution to a certain properly modified equality of scattering. the equality which i propose does not require that the stars should be at equal distances from each other, nor is it necessary that all those of the same nominal magnitude should be equally distant from us." it consisted in allotting a certain equal portion of space to every star, so that, on the whole, each equal portion of space within the stellar system contains an equal number of stars. the space about each star can be considered spherical. suppose such a sphere to surround our own sun. its radius will not differ greatly from the distance of the nearest fixed star, and this is taken as the unit of distance. suppose a series of larger spheres, all drawn around our sun as a centre, and having the radii 3, 5, 7, 9, etc. the contents of the spheres being as the cubes of their diameters, the first sphere will have 3 × 3 × 3 = 27 times the volume of the unit sphere, and will therefore be large enough to contain 27 stars; the second will have 125 times the volume, and will therefore contain 125 stars, and so on with the successive spheres. for instance, the sphere of radius 7 has room for 343 stars, but of this space 125 parts belong to the spheres inside of it; there is, therefore, room for 218 stars between the spheres of radii 5 and 7. herschel designates the several distances of these layers of stars as orders; the stars between spheres 1 and 3 are of the first order of distance, those between 3 and 5 of the second order, and so on. comparing the room for stars between the several spheres with the number of stars of the several magnitudes which actually exists in the sky, he found the result to be as follows: ------------------------------------------------------- order of | number of | | number of distance. | stars there | magnitude. | stars of that | is room for. | | magnitude. ------------------------------------------------------- 1........ | 26 | 1 | 17 2........ | 98 | 2 | 57 3........ | 218 | 3 | 206 4........ | 386 | 4 | 454 5........ | 602 | 5 | 1,161 6........ | 866 | 6 | 6,103 7........ | 1,178 | 7 | 6,146 8........ | 1,538 | | --------------------------------------------------------the result of this comparison is, that if the order of magnitudes could indicate the distance of the stars, it would denote at first a gradual and afterward a very abrupt condensation of them, at and beyond the region of the sixth-magnitude stars. if we assume the brightness of any star to be inversely proportional to the square of its distance, it leads to a scale of distance different from that adopted by herschel, so that a sixth-magnitude star on the common scale would be about of the eighth order of distance according to this scheme--that is, we must remove a star of the first magnitude to eight times its actual distance to make it shine like a star of the sixth magnitude. on the scheme here laid down, herschel subsequently assigned the _order_ of distance of various objects, mostly star-clusters, and his estimates of these distances are still quoted. they rest on the fundamental hypothesis which has been explained, and the error in the assumption of equal intrinsic brilliancy for all stars affects these estimates. it is perhaps probable that the hypothesis of equal brilliancy for all stars is still more erroneous than the hypothesis of equal distribution, and it may well be that there is a very large range indeed in the actual dimensions and in the intrinsic brilliancy of stars at the same order of distance from us, so that the tenth-magnitude stars, for example, may be scattered throughout the spheres which herschel would assign to the seventh, eighth, ninth, tenth, eleventh, twelfth, and thirteenth magnitudes. however this may be, the fact remains that it is from herschel's groundwork that future investigators must build. he found the whole subject in utter confusion. by his observations, data for the solution of some of the most general questions were accumulated, and in his memoirs, which struve well calls "immortal," he brought the scattered facts into order and gave the first bold outlines of a reasonable theory. he is the founder of a new branch of astronomy. _researches for a scale of celestial measures. distances of the stars._ if the stars are _supposed_ all of the same absolute brightness, their brightness to the eye will depend only upon their distance from us. if we call the brightness of one of the fixed stars at the distance of _sirius_, which may be used as the unity of distance, 1, then if it is moved to the distance 2, its apparent brightness will be one-fourth; if to the distance 3, one-ninth; if to the distance 4, one-sixteenth, and so on, the apparent brightness diminishing as the square of the distance increases. the distance may be taken as an order of magnitude. stars at the _distances_ two, three, four, etc., herschel called of the second, third, and fourth magnitudes. by a series of experiments, the details of which cannot be given here, herschel determined the space-penetrating power of each of his telescopes. the twenty-foot would penetrate into space seventy-five times farther than the naked eye; the twenty-five foot, ninety-six times; and the forty-foot, one hundred and ninety-two times. if the seventh-magnitude stars are those just visible to the naked eye, and if we still suppose all stars to be of equal intrinsic brightness, such seventh-magnitude stars would remain visible in the forty-foot, even if removed to 1,344 times the distance of _sirius_ (1,344 = 7 × 192). if, further, we suppose that the visibility of a star is strictly proportional to the total intensity of the light from it which strikes the eye, then a condensed cluster of 25,000 stars of the 1,344th magnitude could still be seen in the forty-foot at a distance where each star would have become 25,000 times fainter, that is, at about 158 times the distance of _sirius_ (158 × 158 = 24,964). the light from the nearest star requires some three years to reach the earth. from a star 1,344 times farther it would require about 4,000 years, and for such a cluster as we have imagined no less than 600,000 years are needed. that is, the light by which we see such a group has not just now left it. on the contrary, it has been travelling through space for centuries and centuries since it first darted forth. it is the ancient history of such groups that we are studying now, and it was thus that herschel declared that telescopes penetrated into time as well as into space. other more exact researches on the relative light of stars were made by herschel. these were only one more attempt to obtain a scale of celestial distances, according to which some notion of the limits and of the interior dimensions of the universe could be gained. two telescopes, _exactly equal_ in every respect, were chosen and placed side by side. pairs of stars which were _exactly equal_, were selected by means of them. by diminishing the aperture of one telescope directed to a bright star, and keeping the other telescope unchanged and directed to a fainter star, the two stars could be equalized in light, and, from the relative size of the apertures, the relative light of this pair of stars could be accurately computed, and so on for other pairs. this was the first use of the method of _limiting apertures_. his general results were that the stars of the first magnitude would still remain visible to the naked eye, even if they were at a distance from us _twelve_ times their actual distance. this method received a still further development at his hands. he did not leave it until he had gained all the information it was capable of giving. he prepared a set of telescopes collecting 4, 9, 16, etc. (2 × 2, 3 × 3, 4 × 4, etc.), times as much light as the naked eye. these were to extend the determinations of distance to the telescopic stars. for example, a certain portion of the heavens which he examined contained no star visible to the naked eye, but many telescopic stars. we cannot say that no one of these is as bright in itself as some of our first-magnitude stars. the smallest telescope of the set showed a large number of stars; these must, then, be _twice_ as far from us, on the average, as the stars just visible to the naked eye. but first-magnitude stars, like _sirius_, _procyon_, _arcturus_, etc., become just visible to the eye if removed to twelve times their present distance. hence the stars seen in this first telescope of the set were between twelve and twenty-four times as far from us as _arcturus_, for example. "at least," as herschel says, "we are certain that if stars of the size and lustre of _sirius_, _arcturus_, etc., were removed into the profundity of space i have mentioned, they would then appear like the stars which i saw." with the next telescope, which collected nine times more light than the eye, and brought into view objects three times more distant, other and new stars appeared, which were then (3 × 12) thirty-six times farther from us than _arcturus_. in the same way, the seven-foot reflector showed stars 204 times, the ten-foot 344 times, the twenty-foot 900 times farther from us than the average first-magnitude star. as the light from such a star requires three years to reach us, the light from the faintest stars seen by the twenty-foot would require 2,700 years (3 × 900). but herschel was now (1817) convinced that the twenty-foot telescope could not penetrate to the boundaries of the milky way; the faintest stars of the galaxy must then be farther from us even than nine hundred times the distance of _arcturus_, and their light must be at least 3,000 years old when it reaches us. there is no escaping a certain part of the consequences established by herschel. it is indeed true that unless a particular star is of the same intrinsic brightness as our largest stars, this reasoning does not apply to it; in just so far as the average star is less bright than the average brightness of our largest stars, will the numbers which herschel obtained be diminished. but for every star of which his hypothesis is true, we may assert that his conclusions are true, and no one can deny, with any show of reason, that, on the whole, his suppositions must be valid. on the whole, the stars which we call faint are farther from us than the brighter ones; and, on the whole, the brilliancy of our brightest and nearest stars is not very far from the brilliancy of the average star in space. we cannot yet define the word _very_ by a numerical ratio. the _method_ struck out by herschel was correct; it is for his successors to look for the special cases and limitations, to answer the question, at a certain distance from us, what are the variations which actually take place in the brilliancy and the sizes of stars? the answer to this question is to be found in the study of the clusters of regular forms, where we _know_ the stars to be all at the same distance from us. _researches on light and heat, etc._ frequently in the course of his astronomical work, herschel found himself confronted by questions of physics which could not be immediately answered in the state of the science at that time. in his efforts to find a method for determining the dimensions of the stellar universe, he was finally led, as has been shown, to regard the brightness of a star as, in general, the best attainable measure of its distance from us. his work, however, was done with telescopes of various dimensions and powers, and it was therefore necessary to find some law for comparing the different results among themselves as well as with those given by observations with an unassisted eye. this necessity prompted an investigation, published in 1800, in which, after drawing the distinction between absolute and intrinsic brightness, herschel gave an expression for the _space-penetrating power_ of a telescope. the reasoning at the base of this conception was as follows. the ratio of the light entering the eye when directed toward a star, to the whole light given out by the star, would be as the area of the pupil of the eye to the area of the whole sphere having the star as a centre and our distance from the star as a radius. if the eye is assisted by a telescope, the ratio is quite different. in that case the ratio of the light which enters the eye to the whole light, would be as the area of the mirror or object-glass to the area of the whole sphere having the star as a centre and its distance as a radius. thus the light received by the _eye_ in the two cases would be as the area of the pupil is to the area of the object-glass. for instance, if the pupil has a diameter of two-fifths of an inch, and the mirror a diameter of four inches, then a hundred times as much light would enter the eye when assisted by the telescope as when unarmed, since the _area_ of the pupil is one-hundredth the _area_ of the objective. if a particular star is just visible to the naked eye, it will be quite bright if viewed with this special telescope, which makes it one hundred times more brilliant in appearance. if we could move the star bodily away from us to a distance ten times its present distance, we could thus reduce its brightness, as seen with the telescope, to what it was at first, as seen with the eye alone, _i. e._, to bare visibility. moving the star to ten times its present distance would increase the surface of the sphere which it illuminates a hundred-fold. we cannot move any special star, but we can examine stars of all brightnesses, and thus (presumably) of all distances. herschel's argument was, then, as follows: since with such a telescope one can see a star ten times as far off as is possible to the naked eye, this telescope has the power of penetrating into space ten times farther than the eye alone. but this number ten, also, expresses the ratio of the diameter of the objective to that of the pupil of the eye, consequently the general law is that the _space-penetrating power_ of a telescope is found by dividing the diameter of the mirror in inches by two-fifths. the diameter of the pupil of the eye (two-fifths of an inch) herschel determined by many measures. this simple ratio would only hold good, however, provided no more light were lost by the repeated reflections and refractions in the telescope than in the eye. that light must be so lost was evident, but no data existed for determining the loss. herschel was thus led to a long series of photometric experiments on the reflecting powers of the metals used in his mirrors, and on the amount of light transmitted by lenses. applying the corrections thus deduced experimentally, he found that the space-penetrating power of his twenty-foot telescope, with which he made his star-gauges, was sixty-one times that of the unassisted eye, while the space-penetrating power of his great forty-foot telescope was one hundred and ninety-two times that of the eye. in support of his important conclusions herschel had an almost unlimited amount of experimental data in the records of his observations, of which he made effective use. by far the most important of herschel's work in the domain of pure physics was published in the same year (1800), and related to radiant heat. the investigation of the space-penetrating powers of telescopes was undertaken for the sole purpose of aiding him in measuring the dimensions of the stellar universe, and there was no temptation for him to pursue it beyond the limits of its immediate usefulness. but here, though the first hint leading to remarkable discoveries was a direct consequence of his astronomical work, the novelty and interest of the phenomena observed induced him to follow the investigation very far beyond the mere solution of the practical question in which it originated. having tried many varieties of shade-glasses between the eye-piece of his telescope and the eye, in order to reduce the inordinate degree of heat and light transmitted by the instrument when directed towards the sun, he observed that certain combinations of colored glasses permitted very little light to pass, but transmitted so much heat that they could not be used; while, on the other hand, different combinations and differently colored glasses would stop nearly all the heat, but allow an inconveniently great amount of light to pass. at the same time he noticed, in the various experiments, that the images of the sun were of different colors. this suggested the question as to whether there was not a different heating power proper to each color of the spectrum. on comparing the readings of sensitive thermometers exposed in different portions of an intense solar spectrum, he found that, beginning with the violet end, he came to the maximum of light long before that of heat, which lay at the other extremity, that is, near the red. by several experiments it appeared that the maximum of illumination, _i. e._, the yellow, had little more than half the heat of the full red rays; and from other experiments he concluded that even the full red fell short of the maximum of heat, which, perhaps, lay even a little beyond the limits of the visible spectrum. "in this case," he says, "radiant heat will at least partly, if not chiefly, consist, if i may be permitted the expression, of invisible light; that is to say, of rays coming from the sun, that have such a momentum[35] as to be unfit for vision. and admitting, as is highly probable, that the organs of sight are only adapted to receive impressions from particles of a certain momentum, it explains why the maximum of illumination should be in the middle of the refrangible rays; as those which have greater or less momenta are likely to become equally unfit for the impression of sight." in his second paper on this subject, published in the same year, herschel describes the experiments which led to the conclusion given above. this paper contains a remarkably interesting passage which admirably illustrates herschel's philosophic method. "to conclude, if we call light, those rays which illuminate objects, and radiant heat, those which heat bodies, it may be inquired whether light be essentially different from radiant heat? in answer to which i would suggest that we are not allowed, by the rules of philosophizing, to admit two different causes to explain certain effects, if they may be accounted for by one. . . . if this be a true account of the solar heat, for the support of which i appeal to my experiments, it remains only for us to admit that such of the rays of the sun as have the refrangibility of those which are contained in the prismatic spectrum, by the construction of the organs of sight, are admitted under the appearance of light and colors, and that the rest, being stopped in the coats and humors of the eye, act on them, as they are known to do on all the other parts of our body, by occasioning a sensation of heat." we now know that the reasoning and conclusion here given are entirely correct, but they have for their basis only a philosophical conception, and not a series of experiments designed especially to test their correctness. such an experimental test of this important question was the motive for a third and last paper in this department of physics. this paper was published in volume ninety of the _philosophical transactions_, and gave the results of two hundred and nineteen quantitative experiments. here we are at a loss to know which to admire most--the marvellous skill evinced in acquiring such accurate data with such inadequate means, and in varying and testing such a number of questions as were suggested in the course of the investigation--or the intellectual power shown in marshalling and reducing to a system such intricate and apparently self-contradictory phenomena. it is true that this discussion led him to a different conclusion from that announced in the previous paper, and, consequently, to a false conclusion; but almost the only escape from his course of reasoning lay in a principle which belongs to a later period of intellectual development than that of herschel's own time. herschel made a careful determination of the quantitative distribution of light and of heat in the prismatic spectrum, and discovered the surprising fact that not only where the light was at a maximum the heat was very inconsiderable, but that where there was a maximum exhibition of heat, there was not a trace of light. "this consideration," he writes, "must alter the form of our proposed inquiry; for the question being thus at least partly decided, since it is ascertained that we have rays of heat which give no light, it can only become a subject of inquiry whether some of these heat-making rays may not have a power of rendering objects visible, superadded to their now already established power of heating bodies. this being the case, it is evident that the _onus probandi_ ought to lie with those who are willing to establish such an hypothesis, for it does not appear that nature is in the habit of using one and the same mechanism with any two of our senses. witness the vibration of air that makes sound, the effluvia that occasion smells, the particles that produce taste, the resistance or repulsive powers that affect the touch--all these are evidently suited to their respective organs of sense." it is difficult to see how the fallacy of this argument could have been detected by any one not familiar with the fundamental physiological law that the nature of a sensation is in no wise determined by the character of the agent producing it, but only by the character of the nerves acted upon; but, as already intimated, this law belongs to a later epoch than the one we are considering. herschel thus finally concluded that light and radiant heat were of essentially different natures, and upon this supposition he explained all of the phenomena which his numerous experiments had shown him. so complete and satisfactory did this work appear to the scientific world, that for a long time the question was looked upon as closed, and not until thirty-five years later was there any dissent. then the italian physicist, melloni, with instrumental means a thousand times more delicate than that of herschel, and with a far larger store of cognate phenomena, collected during the generation which had elapsed, to serve as a guide, discovered the true law. this, as we have seen, was at first adopted by herschel on philosophical grounds, and then rejected, since he did not at that time possess the key which alone could have enabled him to properly interpret his experiments. it is well to summarize the capital discoveries in this field made by herschel, more particularly because his claims as a discoverer seem to have been strangely overlooked by historians of the development of physical science. he, before any other investigator, showed that radiant heat is refracted according to the laws governing the refraction of light by transparent media; that a portion of the radiation from the sun is incapable of exciting the sensation of vision, and that this portion is the less refrangible; that the different colors of the spectrum possess very unequal heating powers, which are not proportional to their luminosity; that substances differ very greatly in their power of transmitting radiant heat, and that this power does not depend solely upon their color; and that the property of diffusing heat is possessed to a varying degree by different bodies, independently of their color. nor should we neglect to emphasize, in this connection, the importance of his measurements of the intensity of the heat and light in the different portions of the solar spectrum. it is the more necessary to state herschel's claims clearly, as his work has been neglected by those who should first have done him justice. in his "history of physics," poggendorff has no reference to herschel. in the collected works of verdet, long bibliographical notes are appended to each chapter, with the intention of exhibiting the progress and order of discovery. but all of herschel's work is overlooked, or indexed under the name of his son. one little reference in the text alone shows that his very name was not unknown. even in the great work of helmholtz on physiological optics, herschel's labors are not taken account of. it is easy to account for this seemingly strange neglect. herschel is known to this generation only as an astronomer. a study of his memoirs will show that his physical work alone should give him a very high rank indeed, and i trust that the brief summaries, which alone can be given here, will have made this plain. * * * * * we may conclude from the time expended, the elaborate nature of the experiments involved, and the character of the papers devoted to their consideration, that the portion of herschel's researches in physics which interested him to the greatest degree, was the investigation of the optical phenomena known as newton's rings. in 1792 he obtained the two object-glasses of huyghens, which were in the possession of the royal society, for the purpose of repeating newton's experiments, and in 1810 he read the last of his three papers on the subject. sir isaac newton had given some of his most vigorous efforts to the study of the phenomena of interference of light, which are exemplified in the colors of thin and of thick plates. the colors of thin plates are most conveniently studied in the regular form which they present when produced by a thin plate of air, limited on one side by a plane polished surface, and on the other by a spherical surface of long radius, such as the exterior surface of a convex lens, for example. the colors are then arranged in concentric circles, and, though others had so produced them before newton, these rings have, ever since the publication of his remarkable work, been known by his name. to explain the phenomena, newton was obliged to supplement his theory of the corpuscular nature of light, by supposing that the inconceivably minute particles constituting light are not always equally susceptible of reflection, but that they have periodically recurring "fits of easy reflection" and of "easy transmission." this conception, though by no means unphilosophical, seemed to herschel too artificial and improbable for ready acceptance, and his effort was to supply a more probable explanation. the developments of optical science have justified herschel in his objections, but we cannot accord to him must any considerable part in making clear the true nature of the phenomenon. indeed, it must be recognized that his position was distinctly less advanced than that of newton. that great philosopher announced the true law governing the relation between the color and the thickness of the film. herschel did not recognize such a relation. newton showed exactly how the phenomenon depended upon the obliquity at which it was viewed. herschel found no place in his theory for this evident variation. in the series of experiments described in the first paper on this subject, herschel mistook the locus of a certain set of rings which he was observing. this mistake, though so slight as hardly to be detected without the guidance of the definite knowledge acquired in later times, not only vitiated the conclusion from the experiments, but gave an erroneous direction to the whole investigation. to him these experiments proved that newton's conception of a periodic phenomenon was untenable. thus cut loose from all hypothesis, his fertility in ideas and ingenuity in experimentation are as striking as ever. he tried the effect of having a polished metal as one of the surfaces limiting the thin plate of air. observing the so-called "blue bow" of newton at the limit of total reflection in a prism, he was led to the discovery of its complement, the "red bow" by refraction. here he thought he had found the solution of his problem, and attributed the rings to the reflection of the light which passed through in the red bow. though mistaken, he had presented to the world of science two experiments which have since played very prominent parts in the undulatory theory of light, namely, the rings formed upon polished metal, and the bands produced by a thin plate near the critical angle. as in his later researches upon the nature of radiant heat, he was wrong in his conclusions, and perhaps with less excuse. his experiments were skilfully devised and most ingenious. his philosophizing was distinctly faulty. we can see not only that he was wrong, but exactly where he began to go wrong. yet these papers are full of interest to the physicist, and by no means deserve the neglect into which they have fallen. _researches on the dimensions of the stars._ herschel examined a number of bright stars, using extremely high magnifying powers, in order to determine whether the stars have sensible dimensions. in a good telescope stars present round and pretty uniformly illuminated disks. if these disks really represent the angular diameter of the stars, they should admit of magnifying, like other objects; but, instead of this, herschel found that they appeared smaller as the telescopic power was increased. he accordingly called the disk of light seen in the telescope a spurious disk. this singular phenomenon gave its discoverer a ready criterion for determining whether a small bright body has an appreciable size, or only impresses the sense of sight by virtue of its intrinsic brightness. if the first were the case, the apparent size would increase with increased magnifying power, while, if the angular dimensions were inappreciable, the apparent size would, on the contrary, diminish with additional magnifying. an occasion for using this criterion came in the first years of this century, with the discovery of three small planets having orbits lying between those of _mars_ and _jupiter_. herschel gave the name _asteroids_ to these bodies. as the appropriateness of this term had been violently assailed, the discovery of _juno_, in 1804, the third one of the group, led to a careful experimental study of the defining power of the telescope used, and of the laws governing the phenomena of spurious disks. with a telescope of about nine inches in aperture, herschel found that if _juno_ subtended an angle greater than a quarter of a second of arc, a certain indication of the fact would have shown itself in the course of the experiments. this conclusion was a justification of the name asteroid, since the appearance of the new planet was strictly stellar. on other grounds, a better name might have been selected. in the paper giving the results of the experiments, the phenomena of the spurious disks are very completely described; but they did not attract the attention which they deserved, and they only became an object of especial interest to students of physics when they were again studied by the famous german optician fraunhofer, a generation later. incidentally the experiments are of interest, as yielding us a measure of the excellence of herschel's telescopes, and a measure which is quite independent of the keenness of his vision. from them we may be sure that the efficiency of the nine-inch mirror used was not sensibly less than that of the highest theoretically attainable excellence. in this connection, too, we may refer to the _philosophical transactions_ for 1790, pp. 468 and 475, where herschel gives observations of both _enceladus_ and _mimas_ seen in contact with the ball of _saturn_. i have never seen so good definition, telescopic and atmospheric, as he must have had on these occasions. _researches on the spectra of the fixed stars._ the spectroscope was applied by secchi to the study of the spectra of the fixed stars visible to the naked eye in the years 1863 to 1866. he examined the nature of the spectrum of each of the larger stars, and found that these stars could be arranged in three general classes or _types_. his results have been verified and extended by other astronomers, and his classification has been generally accepted. according to secchi, the lucid stars may be separated into three groups, distinguished by marked differences in their spectra. secchi's type i. contains stars whose spectra are like those of _sirius_, _procyon_, and _[alpha] lyræ_; his type ii. stars like _arcturus_ and _aldebaran_; his type iii. stars like _[alpha] orionis_. herschel also made some trials in this direction. in the _philosophical transactions_ for 1814 (p. 264), he says: "by some experiments on the light of a few of the stars of the first magnitude, made in 1798, by a prism applied to the eye-glasses of my reflectors, adjustable to any angle and to any direction, i had the following analyses: "the light of _sirius_ consists of red, orange, yellow, green, blue, purple, and violet. _[alpha] orionis_ contains the same colors, but the red is more intense, and the orange and yellow are less copious in proportion than they are in _sirius_. _procyon_ contains all the colors, but proportionately more blue and purple than _sirius_. _arcturus_ contains more red and orange, and less yellow in proportion than _sirius_. _aldebaran_ contains much orange and very little yellow. _[alpha] lyræ_ contains much yellow, green, blue, and purple." here the essential peculiarities of the spectrum of each of the stars investigated by herschel is pointed out, and if we were to use his observations alone to classify these stars into types, we should put _sirius_ and _procyon_ into one type of stars which have "all the colors" in their spectra; _arcturus_ and _aldebaran_ would represent another group of stars, with a deficiency of yellow and an excess of orange and red in the spectrum; and _[alpha] orionis_ would stand as a type of those stars with an excess of red and a deficiency of orange. _[alpha] lyræ_ would represent a sub-group of the first class. herschel's immediate object was not classification, and his observations are only recorded in a passing way. but the fact remains that he clearly distinguished the essential differences of the spectra of these stars, and that he made these observations in support of his statement that the fixed stars, "like the planets, also shine with differently colored light. that of _arcturus_ and _aldebaran_, for instance, is as different from the light of _sirius_ and _capella_ as that of _mars_ and _saturn_ is from the light of _venus_ and _jupiter_." of course, no special discovery can be claimed for him on these few instances. we can see, however, a good example of the manner in which he examined a subject from every side, and used the most remote evidence exactly in its proper place and time. _researches on the variable emission of light and heat from the sun._ it is certainly a remarkable fact that herschel was the first observer to recognize the real importance of the aperture or diameter of a telescope. before his time it was generally assumed that this element only conditioned the amount of light transmitted to the eye, or, in other words, merely determined the brightness of the image. hence the conclusion that if an object is sufficiently bright, the telescope may be made as small as desired without loss of power. thus, in observing the sun, astronomers before herschel had been accustomed to reduce the aperture of their telescopes, in order to moderate the heat and light transmitted. scheiner, it is true, nearly two centuries before the time we are considering, had invented a method for observing the sun without danger, still employing the full aperture. this was by projecting the image of the sun on a white screen beyond the eye-piece, the telescope being slightly lengthened. for special purposes this ingenious method has even been found useful in modern times, though for sharpness of definition it bears much the same relation to the more usual manner of observing, that a photographic picture does to direct vision. although herschel saw the advantages of using the whole aperture of a telescope in such observations, the practical difficulties in the way were very great. we have noted his attempts to find screens which would effectively cut off a large portion of the heat and light without impairing vision, and have considered, somewhat in detail, the remarkable discoveries in radiant heat to which these attempts led him. his efforts were not unsuccessful. a green glass smoked, and a glass cell containing a solution of black writing ink in water--were found to work admirably. thus provided with more powerful instrumental means than had ever been applied to the purpose, herschel turned his attention to the sun. in a very short time he exhausted nearly all there was to be discovered, so that since the publication of his last paper on this subject, in 1801, until the present time, there has been but a single telescopic phenomenon, connected with the physical appearance of the sun, which was unknown to herschel. that phenomenon is the frequent occurrence of a darker central shade or kernel in large spots, discovered by dawes about 1858. herschel, though observing a hundred and ninety years after the earliest discovery of sun spots, seems to have been the first to suspect their periodic character. to establish this as a fact, and to measure the period, was left for our own times and for the indefatigable observer schwabe. the probable importance of such a period in its relation to terrestrial meteorology was not only clearly pointed out by herschel, but he even attempted to demonstrate, from such data as were obtainable, the character of this influence. perhaps no one thing which this great philosopher has done better exhibits the catholic character of his mind than this research. when the possible connection of solar and terrestrial phenomena occurred to him as a question to be tested, there were no available meteorological records, and he could find but four or five short series of observations, widely separated in time. to an ordinary thinker the task would have seemed hopeless until more data had been collected. but herschel's fertile mind, though it could not recall lost opportunities for solar observations, did find a substitute for meteorological records in the statistics of the prices of grain during the various epochs. it is clear that the price of wheat must have depended upon the supply, and the supply, in turn, largely upon the character of the season. the method, as ingenious as it is, failed in herschel's hands on account of the paucity of solar statistics; but it has since proved of value, and has taken its place as a recognized method of research. _researches on nebulæ and clusters._ when herschel first began to observe the nebulæ in 1774, there were very few of these objects known. the nebulæ of _orion_ and _andromeda_ had been known in europe only a little over a hundred years. in 1784 messier published a list of sixty-eight such objects which he had found in his searches for comets, and twenty-eight nebulæ had been found by lacaille in his observations at the cape of good hope. in the mere discovery of these objects herschel quickly surpassed all others. in 1786 he published a catalogue of one thousand new nebulæ, in 1789 a catalogue of a second thousand, and in 1802 one of five hundred. in all he discovered and described two thousand five hundred and eight new nebulæ and clusters. this branch of astronomy may almost be said to be proper to the herschels, father and son. sir john herschel re-observed all his father's nebulæ in the northern hemisphere, and added many new ones, and in his astronomical expedition to the cape of good hope he recorded almost an equal number in the southern sky. of the six thousand two hundred nebulæ now known the herschels discovered at least eight-tenths. the mere discovery of twenty-five hundred nebulæ would have been a brilliant addition to our knowledge of celestial statistics. herschel did more than merely point out the existence and position of these new bodies. each observation was accompanied by a careful and minute description of the object viewed, and with sketches and diagrams which gave the position of the small stars in it and near it.[36] as the nebulæ and clusters were discovered they were placed in classes, each class covering those nebulæ which resembled each other in their general features. even at the telescope herschel's object was not discovery merely, but to know the inner constitution of the heavens. his classes were arranged with this end, and they are to-day adopted. they were: class i. "bright nebulæ (288 in all). ii. "faint nebulæ (909 in all). iii. "very faint nebulæ (984 in all). iv. "planetary nebulæ, stars with burs, with milky chevelure, with short rays, remarkable shapes, etc. (79 in all). v. "very large nebulæ (52 in all). vi. "very compressed and rich clusters of stars (42 in all). vii. "pretty much compressed clusters (67 in all). viii. "coarsely scattered clusters of stars" (88 in all). the lists of these classes were the storehouses of rich material from which herschel drew the examples by which his later opinions on the physical conditions of nebulous matter were enforced. as the nebulæ were discovered and classified they were placed upon a star-map in their proper positions (1786), and, as the discoveries went on, the real laws of the distribution of the nebulæ and of the clusters over the surface of the sky showed themselves more and more plainly. it was by this means that herschel was led to the announcement of the law that the spaces richest in nebulæ are distant from the milky way, etc. by no other means could he have detected this, and i believe this to have been the first example of the use of the graphical method, now become common in treating large masses of statistics. it is still in his capacity of an observer--an acute and wise one--that herschel is considered. but this was the least of his gifts. this vast mass of material was not left in this state: it served him for a stepping-stone to larger views of the nature and extent of the nebulous matter itself. his views on the nature of nebulæ underwent successive changes. at first he supposed all nebulæ to be but aggregations of stars. the logic was simple. to the naked eye there are many groups of stars which appear nebulous. _praesepe_ is, perhaps, the best example. the slightest telescopic power applied to such groups alters the nebulous appearance, and shows that it comes from the combined and confused light of discrete stars. other groups which remain nebulous in a seven-foot telescope, become stellar in a ten-foot. the nebulosity of the ten-foot can be resolved into stars by the twenty-foot, and so on. the nebulæ which remained still unresolved, it was reasonable to conclude, would yield to higher power, and generally a nebula was but a group of stars removed to a great distance. an increase of telescopic power was alone necessary to demonstrate this.[37] "nebulæ can be selected so that an insensible gradation shall take place from a coarse cluster like the _pleiades_ down to a milky nebulosity like that in _orion_, every intermediate step being represented. this tends to confirm the hypothesis that all are composed of stars more or less remote." so, at first, herschel believed that his twenty-foot telescope was of power sufficient to fathom the milky way, that is, to see through it and beyond it, and to reduce all its nebulosities to true groups of stars. in 1791 he published a memoir on _nebulous stars_, in which his views were completely changed. he had found a nebulous star, the sixty-ninth of his class iv., to which his reasons would not apply. in the centre of it was a bright star; around the star was a halo gradually diminishing in brightness from the star outward, and perfectly circular. it was clear the two parts, star and nebula, were connected, and thus at the same distance from us. there were two possible solutions only. either the whole mass was, _first_, composed of stars, in which case the nucleus would be enormously larger than the other stars of its stellar magnitude elsewhere in the sky, or the stars which made up the halo indefinitely small; or, _second_, the central nucleus was indeed a star, but a star surrounded with "a shining fluid, of a nature totally unknown to us." the long strata of nebulæ, which he had before described under the name of "telescopic milky ways," might well be accounted for by masses of this fluid lying beyond the regions of the seventh-magnitude stars. this fluid might exist independently of stars. if it is self-luminous, it seems more fit to produce a star by its condensation, than to depend upon the star for its own existence. such were a few of the theorems to which his discovery of this nebula led him. the hypothesis of an elastic _shining fluid_ existing in space, sometimes in connection with stars, sometimes distinct from them, was adopted and never abandoned. how well the spectroscope has confirmed this idea it is not necessary to say. we know the shining fluid does exist, and in late years we have seen the reverse of the process imagined by herschel. a star has actually, under our eyes, become a planetary nebula, and the cycle of which he gave the first terms is complete. in five separate memoirs (1802, 1811, 1814, 1817, and 1818) herschel elaborated his views of the sidereal system. the whole extent of his views must be gained from the extended memoirs themselves. here only the merest outline can be given. in 1802 there is a marshaling of the various objects beyond our solar system. the stars themselves may be _insulated_, or may belong to _binary_ or _multiple_ systems, to _clusters_ and groups, or to grand groups like the milky way. nebulæ may have any of the forms which have been described; and, in 1811, he gives examples of immense spaces in the sky covered with diffused and very faint nebulosity. "its abundance exceeds all imagination."[38] these masses of nebular matter are the seats of attracting forces, and these forces must produce condensation. when a nebula has more than one preponderating seat of attracting matter, it may in time be divided, and the double nebulæ have had such an origin. when nebulæ appear to us as round masses, they are in reality globular in form, and this form is at once the effect and the proof of a gravitating cause. the central brightness of nebulæ points out the seat of the attraction; and the completeness of the approximation to a spherical form points out the length of time that the gravitating forces have been at work. those nebulæ (and clusters) which are most perfect in the globular form, have been longest exposed to central forces. the planetary nebulæ are the oldest in our system. they must have a rotatory motion on their axes. by progressive condensation planetary nebulæ may be successively converted into bright stellar nebulæ, or into nebulous stars, and these again, by the effects of the same cause, into insulated or double stars. this chain of theorems, laid down in the memoir of 1811, is enforced in 1814 with examples which show how the nebulous appearance may grow into the sidereal. herschel selects from the hundreds of instances in his note-books, nebulæ in every stage of progress, and traces the effect of condensation and of clustering power through all its course, even to the final breaking up of the milky way itself. the memoirs of 1817 and 1818 add little to the general view of the physical constitution of the heavens. they are attempts to gain a scale of celestial measures by which we may judge of the distances of the stars and clusters in which these changes are going on. there is little to change in herschel's statement of the general construction of the heavens. it is the groundwork upon which we have still to build. every astronomical discovery and every physical fact well observed is material for the elaboration of its details or for the correction of some of its minor points. as a scientific conception it is perhaps the grandest that has ever entered into the human mind. as a study of the height to which the efforts of one man may go, it is almost without a parallel. the philosopher who will add to it to-day, will have his facts and his methods ready to his hands. herschel presents the almost unique example of an eager observer marshaling the multitude of single instances, which he himself has laboriously gathered, into a compact and philosophic whole. in spite of minor errors and defects, his ideas of the nature of the sidereal universe have prevailed, and are to-day the unacknowledged basis of our every thought upon it. some of its most secret processes have been worked out by him, and the paths which he pointed out are those along which our advances must be made. in concluding this condensed account of herschel's scientific labors, it behoves us to remember that there was nothing due to accident in his long life. he was born with the faculties which fitted him for the gigantic labors which he undertook, and he had the firm basis of energy and principle which kept him steadily to his work. as a practical astronomer he remains without an equal. in profound philosophy he has few superiors. by a kindly chance he can be claimed as the citizen of no one country. in very truth his is one of the few names which belong to the whole world. footnotes: [31] james short, f.r.s. (1710-1768), and john dollond, f.r.s. (1706-1761), were the most celebrated makers of telescopes of their day. the six-foot newtonian reflectors of short (aperture 9.4 inches), and the forty-six-inch achromatics of dollond (aperture 3.6 inches), were highly esteemed. the royal observatory of greenwich possessed, in 1765, one of each class. in a comparative trial of short's telescope, at greenwich, and one of herschel's first telescopes, the latter was adjudged greatly superior. [32] at least _one_ of these telescopes had the principal mirror made of glass instead of metal.--_philosophical transactions_, 1803. [33] the following extract from fourier's _éloge_ of herschel is of interest in this connection. the sum first appropriated by the king was £2,000. this was afterwards raised to £4,000, and a sum of £200 yearly was given for maintenance. "l'histoire doit conserver à jamais la réponse de ce prince à un étranger célèbre [lalande?] qui le remerciait des sommes considérables accordées pour les progrès de l'astronomie. 'je fais les dépenses de la guerre,' dit le roi, 'parcequ'elles sont nécessaires; quant à celles des sciences, il m'est agréable des les ordonner; leur objet ne coûte point des larmes, et honore l'humanité.'" lalande's own account is a little different. he says the king exclaimed: "ne vaut-il pas mieux employer son argent à cela qu'à faire tuer des hommes?" [34] the memoirs on the parallaxes of stars, written by various astronomers from 1750 to 1800, were mainly directed to the improvement of the methods, or to the discovery of the parallax of some particular star. for example, lacaille's observations of _sirius_, at the cape of good hope, had resulted in a parallax of 9" for that star--a quantity over forty times too large. [35] herschel accepted, as did all his cotemporaries, the newtonian or corpuscular theory of light. [36] thus the position of small stars critically situated in the centre, or on the edges of the nebulæ was always noted. many of the descriptions are given in the published papers, but the publication of the diagrams would be an immense help to this branch of astronomy. d'arrest in his reduction of herschel's nebula observations (1856) writes: "gewiss wäre es vom höchsten interesse für die entwickelung, welche hoffentlich auch dieser zweig der beobachtenden astronomie zukünftig erhalten wird, wenn die herschel'schen beobachtungen in der ausführlichkeit in welcher sie, verschiedenen andeutungen zufolge, _handschriftlich_ vorhanden sind, veröffentlicht würden. es schliesst sich dieser wunsch in betreff der nebelflecken lebhaft an den an, welcher, schon vor einem jahrzehnt nach veröffentlichung der 400 noch unedirten _star-gauges_ von gewichtigerer seite her geäussert wurde." in this all must agree who have a knowledge of the direction in which we must look for advances in the difficult and important questions of the distance, the motions, and the changes of the nebulæ. almost the only aid to be looked for from the older observations must come from such diagrams, and we may safely say that the publication of this priceless material, just as it stands, would carry our exact data back from 1833 to 1786, or no less than forty-seven years. [37] long after herschel had abandoned this idea, it continued current among astronomers. the successes of lord rosse's telescope perpetuated to the middle of the nineteenth century an erroneous view which herschel had given up in 1791. [38] these have never been re-observed. they should be sought for with a powerful refractor, taking special precautions against the illumination of the field of view from neighboring bright stars. herschel's reflectors were specially open to illusions produced in this way. his observations probably will remain untested until some large telescope is used in the way he adopted, _i. e._, in sweeping. bibliography. i.--list of the published writings of william herschel on astronomical subjects. [in chronological order.] _n.b.--in general, translations and abstracts of those which appeared in periodicals are not noticed here. i have made exceptions in the more important cases._ [solution of a prize question. _see_ this book, page 46.] _ladies' diary_, 1779. astronomical observations on the periodical star in _collo ceti_. _phil. trans._, 1780, p. 338. astronomical observations relating to the mountains of the moon. _phil. trans._, 1780, p. 507. astronomical observations on the rotation of the planets round their axes, made with a view to determine whether the earth's diurnal motion is perfectly equable. _phil. trans._, 1781, p. 115. account of a comet. [dated 13th march, 1781. this was _uranus_.] _phil. trans._, 1781, p. 492. on the parallax of the fixed stars. _phil. trans._, 1782, p. 82. catalogue of double stars. _phil. trans._, 1782, p. 112: translation in _bode's jahrbuch_, 1786, p. 187. description of a lamp micrometer and the method of using it. _phil. trans._, 1782, p. 163. a paper to obviate some doubts concerning the great magnifying powers used. _phil. trans._, 1782, p. 173. a letter from william herschel, esq., f.r.s., to sir joseph banks, _bart._, p.r.s. _phil. trans._, 1783, p. 1. aus einem schreiben des hrn. herschel an mich [bode], datirt london, den 13ten august, 1783. [this is a letter forwarding herschel's memoir on the parallax of the fixed stars, etc.] _bode's jahrbuch_, 1786, p. 258. on the diameter and magnitude of the _georgium sidus_, with a description of the dark and lucid disk and periphery micrometers. _phil. trans._, 1783, p. 4. on the proper motion of the sun and solar system, with an account of several changes that have happened among the fixed stars since the time of mr. flamsteed. _phil. trans._, 1783, p. 247. _bode's jahrbuch_, 1787, p. 194, p. 224. astronomische nachrichten und entdeckungen, aus einem französischen schreiben desselben an mich [bode], datirt datchet, nahe bey windsor, den 18. mai, 1784. [this letter is on the subject of the use of high magnifying powers, and gives a _résumé_ of his recent papers.] _bode's jahrbuch_, 1787, p. 211. on the remarkable appearances at the polar regions of the planet _mars_, the inclination of its axis, the position of its poles and its spheroidical figure; with a few hints relating to its real diameter and atmosphere. _phil. trans._, 1784, p. 233. account of some observations tending to investigate the construction of the heavens. _phil. trans._, 1784, p. 437. [_bode's jahrbuch_, 1788, p. 246, has a summary of this paper by baron von zach. see, also, _bode's jahrbuch_, 1794, p. 213.] catalogue of double stars. _phil. trans._, 1785, p. 40. on the construction of the heavens. _phil. trans._, 1785, p. 213. _bode's jahrbuch_, 1788, p. 238. see, also, _same_, 1787, p. 213, and 1794, p. 213. aus einem schreiben des hrn. herschel an mich [bode], datirt clay hall, nahe bey windsor, den 20. jul., 1785. [this is a letter forwarding two memoirs, and giving the prices of telescopes] _bode's jahrbuch_, 1788, p. 254. catalogue of one thousand new nebulæ and clusters of stars. _phil. trans._, 1786, p. 457. _bode's jahrbuch_, 1791, p. 157, and _same_, 1794, p. 213. investigation of the cause of that indistinctness of vision which has been ascribed to the smallness of the optic pencil. _phil. trans._, 1786, p. 500. remarks on the new comet [1786, ii.]. _phil. trans._, 1787, p. 4. [letter from herschel to bode on the discovery of two satellites to _uranus_, dated slough, 1787, feb. 11.] _bode's jahrbuch_, 1790, p. 253. an account of the discovery of two satellites revolving round the _georgian planet_. _phil. trans._, 1787, p. 125. _bode's jahrbuch_, 1791, p. 255. an account of three volcanoes in the moon. _phil. trans._, 1787, p. 229. _bode's jahrbuch_, 1791, p. 255. note on m. méchain's comet. [1787, i.] [added to preceding paper.] _phil. trans._, 1787, p. 232. on the _georgian planet_ and its satellites. _phil. trans._, 1788, p. 364. _bode's jahrbuch_, 1793, p. 104. observations on a comet [1788, ii.]. _phil. trans._, 1789, p. 151. catalogue of a second thousand of new nebulæ and clusters of stars, with a few introductory remarks on the construction of the heavens. _phil. trans._, 1789, p. 212. _bode's jahrbuch_, 1793, p. 104. also, _same_, 1794, p. 150. account of the discovery of a sixth and seventh satellite of the planet _saturn_, with remarks on the construction of its ring, its atmosphere, its rotation on an axis, and its spheroidical figure. _phil. trans._, 1790, p. 1. _bode's jahrbuch_, 1793, p. 239; _same_, 1796, p. 88; 1797, p. 249. on the satellites of the planet _saturn_, and the rotation of its ring on an axis. _phil. trans._, 1790, p. 427. on nebulous stars properly so called. _phil. trans._, 1791, p. 71. _bode's jahrbuch_, 1801, p. 128. on the ring of _saturn_ and the rotation of the fifth satellite upon its axis. _phil. trans._, 1792, p. 1. _bode's jahrbuch_, 1796, p. 88. miscellaneous observations. [account of a comet], p. 23 [1792, i.]. [on the periodical appearance of omicron ceti], p. 24. [on the disappearance of the 55th _herculis_], p. 26. [remarkable phenomenon in an eclipse of the moon], p. 27. _phil. trans._, 1792, p. 23. observations on the planet _venus_. _phil. trans._, 1793, p. 201. observations of a quintuple belt on the planet _saturn_. _phil. trans._, 1794, p. 28. _bode's jahrbuch_, 1798, p. 90. account of some particulars observed during the late eclipse of the sun. [1793, september 5th.] _phil. trans._, 1794, p. 39. on the rotation of the planet _saturn_ upon its axis. _phil. trans._, 1794, p. 48. _bode's jahrbuch_, 1798, p. 74. on the nature and construction of the sun and fixed stars. _phil. trans._, 1795, p. 46. _bode's jahrbuch_, ii. suppl. band, p. 65. description of a forty-foot reflecting telescope. _phil. trans._, 1795, p. 347. _bode's jahrbuch_, iii. suppl. band, p. 238. additional observations on the comet. [1796, i.] _phil. trans._, 1796, p. 131. on the method of observing the changes that happen to the fixed stars; with some remarks on the stability of the light of our sun. to which is added a catalogue of comparative brightness for ascertaining the permanency of the lustre of stars. _phil. trans._, 1796, p. 166. _bode's jahrbuch_, 1809, p. 201. on the periodical star _[alpha] herculis_; with remarks tending to establish the rotatory motion of the stars on their axes; to which is added a second catalogue of the comparative brightness of the stars. _phil. trans._, 1796, p. 452. _bode's jahrbuch_, 1809, p. 201. a third catalogue of the comparative brightness of the stars, with an introductory account of an index to mr. flamsteed's observations of the fixed stars, contained in the second volume of the historia coelestis. to which are added several useful results derived from that index. _phil. trans._, 1797, p. 293. _bode's jahrbuch_, 1810, p. 143. observations of the changeable brightness of the satellites of _jupiter_, and of the variation in their apparent magnitudes, with a determination of the time of their rotatory motions on their axes. to which is added a measure of the diameter of the second satellite, and an estimate of the comparative size of all the four. _phil. trans._, 1797, p. 332. _bode's jahrbuch_, 1801, p. 103. on the discovery of four additional satellites of the _georgium sidus_. the retrograde motion of its old satellites announced, and the cause of their disappearance at certain distances from the planet explained. _phil. trans._, 1798, p. 47. _bode's jahrbuch_, 1801, p. 231. a fourth catalogue of the comparative brightness of the stars. _phil. trans._, 1799, p. 121. _bode's jahrbuch_, 1810, p. 143. on the power of penetrating into space by telescopes, with a comparative determination of the extent of that power in natural vision, and in telescopes of various sizes and constructions, illustrated by select observations. _phil. trans._, 1800, pp. 49-85. _bode's jahrbuch_, 1804, p. 231. investigation of the powers of the prismatic colors to heat and illuminate objects, with remarks that prove the different refrangibility of radiant heat. to which is added an inquiry into the method of viewing the sun advantageously with telescopes of large apertures and high magnifying powers. _phil. trans._, 1800, pp. 255-283. _bode's jahrbuch_, 1804, p. 89. experiments on the refrangibility of the invisible rays of the sun. _phil. trans._, 1800, pp. 284-292. _bode's jahrbuch_, 1804, p. 89. experiments on the solar and on the terrestrial rays that occasion heat, with a comparative view of the laws by which light and heat, or rather the rays that occasion them, are subject, in order to determine whether they are the same or different. _phil. trans._, 1800, pp. 293-326, 437-538. _gilbert annal._, x. (1802), pp. 68-78; _same_, xii. (1803), pp. 521-546. observations tending to investigate the nature of the sun, in order to find the causes or symptoms of its variable emission of light and heat, with remarks on the use that may possibly be drawn from solar observations. _phil. trans._, 1801, pp. 265-318. _bode's jahrbuch_, 1805, p. 218, and 1806, p. 113. ueber den 7 nebelfleck der 1sten classe des herschel'schen verzeichniss, und ueber _ceres_ und _pallas_, vom herrn doctor herschel, aus zwey briefen desselben. _bode's jahrbuch_, 1805, p. 211. additional observations tending to investigate the symptoms of the variable emission of the light and heat of the sun, with trials to set aside darkening glasses by transmitting the solar rays through liquids, and a few remarks to remove objections that might be made against some of the arguments contained in the former paper. _phil. trans._, 1801, pp. 354-362. observations on the two lately discovered celestial bodies [_ceres and pallas_]. _phil. trans._, 1802, pp. 213-232. _nicholson journal_, iv. (1808), pp. 120-130, 142-148. catalogue of five hundred new nebulæ, nebulous stars, planetary nebulæ, and clusters of stars, with remarks on the construction of the heavens. _phil. trans._, 1802, pp. 477-528. _bode's jahrbuch_, 1807, p. 113. observations of the transit of _mercury_ over the sun's disk, to which is added an investigation of the causes which often prevent the proper action of mirrors. _phil. trans._, 1803, pp. 214-232. account of the changes which have happened during the last twenty-five years in the relative situation of double stars, with an investigation of the cause to which they are owing. _phil. trans._, 1803, pp. 339-382. _bode's jahrbuch_, 1808, pp. 154-178. continuation of the account of the changes that have happened in the relative situation of double stars. _phil. trans._, 1804, pp. 353-384. _bode's jahrbuch_, 1808, p. 226. aus einem schreiben des herrn doctor herschel, datirt slough, bey windsor, den 31. may, 1804. [relates to his theory of the relation between the solar radiation and the price of wheat.] _bode's jahrbuch_, 1808, p. 226. experiments for ascertaining how far telescopes will enable us to determine very small angles, and to distinguish the real from the spurious diameters of celestial and terrestrial objects, with an application of the results of those experiments to a series of observations on the nature and magnitude of mr. harding's lately discovered star [_juno_ (1804),]. _phil. trans._, 1805, pp. 31-70. on the direction and velocity of the motion of the sun and solar system. _phil. trans._, 1805, pp. 233-256. _bode's jahrbuch_, iv. suppl. band, p. 67. observations on the singular figure of the planet _saturn_. _phil. trans._, 1805, pp. 272-280. _bode's jahrbuch_, 1809, p. 197. on the quantity and velocity of solar motion. _phil. trans._, 1806, pp. 205-237. _bode's jahrbuch_, 1811, p. 224. observations and remarks on the figure, climate, and atmosphere of _saturn_ and its ring. _phil. trans._, 1806, pp. 455-467. _gilbert annal._, xxxiv. (1810), pp. 82-105. _bode's jahrbuch_, 1810, p. 228. experiments for investigating the cause of the colored concentric rings discovered by sir i. newton between two object-glasses laid one upon another. _phil. trans._, 1807, pp. 180-233. _annal. de chimie_, lxx., 1809, pp. 154-181, 293-321; _same_, lxxi., 1809, pp. 5-40. observations on the nature of the new celestial body [_vesta_] discovered by dr. olbers, and of the comet which was expected to appear last january in its return from the sun. [1806, ii.] _phil. trans._, 1807, pp. 260-266. observations of a comet [1807, i.] made with a view to investigate its magnitude and the nature of its illumination, to which is added an account of a new irregularity lately perceived in the apparent figure of the planet _saturn_. _phil. trans._, 1808, pp. 145-163. _gilbert annal._, xxxvi. (1810), pp. 389-393. _zach, monat. corresp._, xx. (1809), pp. 512-514. continuation of experiments for investigating the cause of colored concentric rings and other appearances of a similar nature. _phil. trans._, 1809, pp. 259-302. supplement to the first and second part of the paper of experiments for investigating the cause of colored concentric rings between object-glasses, and other appearances of a similar nature. _phil. trans._, 1810, pp. 149-177. _gilbert annal._, xlvi., 1814, pp. 22-79. astronomical observations relating to the construction of the heavens, arranged for the purpose of a critical examination, the result of which appears to throw some new light upon the organization of the celestial bodies. _phil. trans._, 1811, pp. 269-336. _journ. de phys._, lxxv., 1812, pp. 121-167. observations of a comet, with remarks on the construction of its different parts [1811, i.]. _phil. trans._, 1812, pp. 115-143. _journ. de phys._, lxxvii., 1813, pp. 125-135. _zach, monat. corresp._, xxviii., 1813, pp. 455-469, 558-568. _bode's jahrbuch_, 1816, p. 185. observations of a second comet, with remarks on its construction [1811, ii.]. _phil. trans._, 1812, pp. 229-237. _nicholson journ._, xxxv., 1813, pp. 193-199. _bode's jahrbuch_, 1816, p. 203. astronomical observations relating to the sidereal part of the heavens, and its connection with the nebulous part, arranged for the purpose of a critical examination. _phil. trans._, 1814. pp. 248-284. _bode's jahrbuch_, 1818, pp. 97-118. a series of observations of the satellites of the _georgian planet_, including a passage through the node of their orbits, with an introductory account of the telescopic apparatus that has been used on this occasion, and a final exposition of some calculated particulars deduced from the observations. _phil. trans._, 1815, pp. 293-362. _bode's jahrbuch_, 1819, p. 232-242. astronomical observations and experiments tending to investigate the local arrangement of the celestial bodies in space, and to determine the extent and condition of the milky way. _phil. trans._, 1817, pp. 302-331. _bode's jahrbuch_, 1821, p. 149. astronomical observations and experiments selected for the purpose of ascertaining the relative distances of clusters of stars, and of investigating how far the power of our telescopes may be expected to reach into space, when directed to ambiguous celestial objects. _phil. trans._, 1818, pp. 429-470. on the places of one hundred and forty-five new double stars (1821). _mem. roy. ast. soc._, 1, 1822, pp. 166-181. ii.--list of works relating to the life and writings of william herschel. [arranged alphabetically by authors.] _n.b.--in general, the notices of his life to be found in encyclopædias of biography, etc., are not included here._ arago (f.) analyse de la vie et des travaux de sir william herschel [from _annuaire du bureau des longitudes_, 1842]. paris, 1843. 18mo. [see also the _annuaire_ for 1834, for an account of herschel's work on double stars.] arago (f.) biographies of distinguished scientific men. translated by admiral w. h. smyth, rev. b. powell, and robert grant, esq. herschel. first series, p. 258. boston, 1859. 8vo. arago (f.) herschel. [translated from the french.] smithsonian report. 1870. p. 197. 8vo. auwers (a.) william herschel's verzeichnisse von nebelflecken und sternhaufen bearbeitet von a. auwers. from the _königsberg observations_. 1862. folio. bessel (f. w.) sir william herschel. [from the _königsberger allgemeine zeitung_, 1, 1843, no. 37, _et seq._, reprinted in his] _abhandlungen_, vol iii., p. 468. leipzig, 1876. 4to. d'arrest (h. l.) verzeichniss von sir william herschel's nebelflecken _erster_ und _vierter_ classe, aus den beobachtungen berechnet und auf 1850 reducirt. _abhandlungen der math. phys. classe der k. sächs gesells. d. wissenschaften_, band iii. [1857], p. 359. dunkin (e.) obituary notices of astronomers, p. 86. sir william herschel, k.c.h., f.r.s., 1738-1822. london, 1879. 12mo. fétis (f. j.) biographie universelle des musiciens [article herschel]. paris, 1835-37. 8vo. forbes (j. d.) sir william herschel [being § 2 of dissertation vi.]. encyclopædia britannica, eighth edition. vol. i.,_dissertations_, p. 838. fourier (j.) éloge historique de sir william herschel, prononcé dans la séance publique de l'académie royale des sciences le 7 juin, 1824. _historie de l'académie royale des sciences de l'institut de france_, _tome_ vi., _année_ 1823, p. lxi. harding (c. l.) des herrn dr. herschel's untersuchungen über die natur der sonnenstrahlen, aus dem englischen übersetzt. erstes heft. [translations from _phil. trans._, 1800.] celle, 1801. 16mo. hastings (c. s.) see holden _and_ hastings. herschel (carolina.) an account of a new comet. [1786, ii.] _phil. trans._, 1787, vol. lxxvii., p. 1. herschel (carolina.) an account of the discovery of a comet. [1793, i.] _phil. trans._, 1794, vol. lxxxiv., p. 1. herschel (carolina.) account of the discovery of a comet. [1795, ii.] _phil. trans._, 1796, vol. lxxxvi., p. 131. herschel (carolina.) catalogue of stars taken from flamsteed's observations contained in the second volume of his _historia coelestis_, and not inserted in the british catalogue; to which is added a collection of errata which should be noticed in the same volume; with remarks by w. herschel. london, 1798. folio. herschel (carolina.) verzeichniss von 74 sternen flamsteeds von denen keine beobachtungen in der _hist. coel. brit._ vorkommen. _bode's jahrbuch_, 1806, p. 255 [herschel (carolina.)] [notice of her life.] _monthly notices roy. ast. soc._, vol. 8, p. 64; _also_, _memoirs roy. ast. soc._, vol. 17, p. 120. [herschel (carolina.)] memoir and correspondence of caroline herschel. by mrs. john herschel. with portraits. london, 1876. 12mo. herschel (j. f. w.) article _telescope_, in encyclopædia britannica, eighth edition. [this article (illustrated) gives most of the important features of sir william herschel's manner of grinding and polishing specula.] herschel (j. f. w.) catalogue of nebulæ and clusters of stars. [general and systematic reduction of all sir w. herschel's observations brought into connection with all other similar ones.] _phil. trans._, 1864. page 1. 4to. herschel (j. f. w.) a synopsis of all sir william herschel's micrometrical measurements, etc., of double stars, together with a catalogue of those stars . . . for 1880. _mem. roy. ast. soc._, vol. 35, p. 21. lond., 1867. 4to. herschel (j. f. w.) additional identifications of double stars in the synoptic catalogues of sir william herschel's micrometrical measurements, etc. _monthly notices roy. ast. soc._, vol. 28, p. 151. london, 1868. 8vo. herschel (mrs. john.) memoir and correspondence of caroline herschel. with portraits. london, 1876. 12mo. herschel (w.) [solution of a prize question. _see_ this book, page 46.] _ladies' diary_, 1779. herschel (w.) the favorite eccho catch . . . and the preceding glee [by s. leach]. to which is added the . . . catch sung by three old women . . . in the pantomime called "the genius of nonsense" [by h. harington]. london, 1780(?). obl. folio. [a ms. copy of this was kindly furnished me by dr. r. garnett, of the british museum.] herschel (w.) _göttingen magazin der wissenschaften und literatur_ (1783), vol. iii., p. 4. lichtenberg and forster, editors. [letter from herschel, giving a brief account of his life. _see_ this book, page 3.] herschel (w.) i. _manuscripts in possession of the royal society._ 1. a series of register sheets in which are entered up _all_ the observations of _each_ nebula, copied _verbatim_ from the sweeps. 2. a similar set of register sheets for messier's nebulæ. 3. a general index of the 2,508 nebulæ of w. herschel; given the class and number, to find the general number. 4. an index list; given the general number, to find the class and number. 5. a more complete list like 4. 6. a manuscript catalogue of all the nebulæ and clusters, reduced to 1,800, and arranged in zones of 1° in polar distance; by miss carolina herschel. 7. the original sweeps with the 20-foot reflector at slough, in three small 4to and four folio vols. of ms. ii. _manuscripts in possession of the royal astronomical society._ this library contains "the whole series of autograph observations of each double star [observed by herschel], brought together on separate sheets by sir william herschel and miss carolina herschel." [herschel (w.)] some account of the life and writings of william herschel, esq. [with a portrait.] the _european magazine and london review_ for january, 1785. 8vo. [herschel (w.)] _edinburgh review_, vol. i., p, 426. [a review of herschel's memoir, "observations on the two lately discovered bodies," from _phil. trans._, 1802. _see_ this book, page 96.] [herschel (w.)] "sir william herschel, from a london paper." [this is a short obituary notice "furnished by a gentleman well acquainted with sir william and his family, and its accuracy may be relied on."] _niles' register_, vol. 23, p. 154. nov. 9, 1822. 8vo. [herschel (w.)] obituary: sir william herschel, knt., ll.d., f.r.s. _the gentleman's magazine and historical chronicle_, vol. xcii., 1822, p. 274. 8vo. [herschel (w.)] _annual register_, 1822, p. 289. 8vo. [herschel (w.)] w. herschel's sämmtliche schriften, erster band. ueber den bau des himmels. mit 10 kupfertafeln. [edited by j. w. pfaff. a second edition was published in 1850.] dresden and leipzig, 1828. 8vo. [herschel (w.)] _new york mirror_, vol. vi., 1829-30, p. 388. [herschel (w.)] _living age_, vol. ii., p. 125 (1844). 8vo. [reprinted from _chambers' journal_.] [herschel (w.)] _foreign quarterly review_, vol. 31, p. 438. 8vo. [review of arago's "analyse de la vie et des travaux de sir william herschel."] [herschel (w.)] arago's life of herschel. _eclectic museum_, vol. ii., p. 556. [reprinted from the _foreign quarterly review_, vol. 31.] holden (e. s.) on the inner satellites of _uranus_. [reduction of sir william herschel's observations.] _proceedings amer. assn. adv. science_, _august_, 1874, p. 49. 8vo. holden (e. s.) index catalogue of books and memoirs relative to nebulæ, clusters, etc. _smithsonian miscellaneous collections_, no. 311, pp. 19-38. [abstracts of sir william herschel's memoirs (on nebulæ) in the _philosophical transactions_.] washington, 1877. 8vo. holden (e. s.) and c. s. hastings. a subject-index and a synopsis of the scientific writings of sir william herschel. [reprinted from the _report_ of the smithsonian institution (1879).] washington, 1881. 8vo. krafft (j. g. f.) kurze nachricht von dem berühmten astronomen herschel und einigen seiner entdeckungen. bayreuth, 1787. 8vo. peirce (c. s.) photometric researches. [a reduction of herschel's observations on the comparative brightness of the stars.] _annals harvard college observatory_, vol. ix. leipzig, 1878. 4to. sommer (g. m.) william herschel . . . ueber den bau des himmels; drei abhandlungen aus dem englischen uebersetzt, nebst einem authentischen auszug aus kants allgemeiner naturgeschichte und theorie des himmels. koenigsberg, 1791. 8vo. struve (w.) études d'astronomie stellaire. sur la voie lactée et sur la distance des étoiles fixes. [p. 24 _et seq._ contains an elaborate review of the construction of the heavens according to herschel.] st. petersburg, 1847. 8vo. wolf (r.) william herschel. zurich, 1867. 8vo. zach (f. von.) dr. william herschel [translated from _public characters_ and printed in zach's _monatlich correspondenz_, 1802, part i., p. 70 _et seq._] iii.--list of the published portraits of william herschel. _artist_, mme. dupiery. _engraver_, thönert. 8vo. early portrait. some copies in red. profile. _artist_, f. rehburg. _engraver_, f. w. bollinger. 8vo. late portrait. _artist_, ----? _engraver_, c. westermayr. 8vo. medallion. _artist_, c. brand. _engraver_, ----? 8vo. lithograph. _artist_, ----? _engraver_, j. sewell. 8vo. profile, 1785. _artist_, ----? _engraver_, ----? 8vo. profile. _artist_, f. bonneville. _engraver_, f. bonneville. 8vo. profile. _artist_, j. russell, r.a. _engraver_, e. scriven. 8vo. engraved from a crayon in the possession of his son, and published by the s. d. u. k. in the _gallery of portraits_, vol. 5. _artist_, ----? _engraver_, ----? 8vo. _european magazine_, jan., 1785. this is a bust in profile, showing the left side of the face. _artist_, ----? _engraver_, thomson. 8vo. published by caxton, 1823. this must have been engraved before 1816 since the legend is william herschel, ll.d., f.r.s. _artist_, lady gordon. from the painting by abbott in the national portrait gallery. _engraver_, joseph brown. 8vo. published in memoir of caroline herschel. this is of the date 1788, or thereabouts. _see_ frontispiece. _artist_, ----? _engraver_, c. müller. 4to. medallion, 1785(?). _artist_, ----? _engraver_, h. pinhas. 4to. legend in russian. _artist_, baisch. _engraver_, ----? 4to. lithograph. _artist_, h. grévedon. _engraver_, ----? fol. lithograph. _artist_, ----? _engraver_, f. müller. fol. _artist_, abbott. _engraver_, ryder. fol. 1788. _artist_, j. boilly. _engraver_, ----? fol. 1822. lithograph. _artist_, ----? _engraver_, j. godby. fol. r. w. s. lutwidge, esq., f.r.a.s., has an original seal with a head of sir william herschel, which is shown on the title-page of this work. a cut of it has been courteously furnished me by john browning, esq., f.r.a.s., etc. in 1787 a bust of herschel was made by lockie for sir william watson. a picture of herschel was painted by mr. artaud about the beginning of 1819. a portrait of herschel by abbott is in the national portrait gallery, london. there are no doubt many other paintings in england, though i can find notices of these only. the royal society of london has nearly a hundred portraits of its most distinguished members, but owns none of sir william herschel. index of names. _n.b.--this index is intended to refer to the proper names occurring in the body of the work only, and not to the bibliography._ airy (sir george), 17. alison (sir archibald), 111. arago (françois), 49, 81, 139. artaud (m.), 114. aubert (alexander), 52, 62, 63. baldwin (miss), 115. banks (sir joseph), 56, 58, 64. bessel (f. w.), 127, 137. blagden (dr.), 57. bonaparte (napoleon), 108, 111. bradley (james), 51, 153. bruhl (count von), 52. bulman (mr.), 22, 115, 116. bunsen (chevalier), 12. burney (dr.), 82, 101, 102, 104, 105, 106. campbell (thomas), 107. cassini (j. d.), 51. cropley (mr.), 20. dalrymple (mr.), 73. d'arblay (madame), 100 _et seq._ darlington (earl of), 18. darquier, 51, 119. d'arrest (h. l.), 204. dawes (w. r.), 200. de luc (m.), 64. de luc (mrs.), 100, 102. dollond (j.), 120. engelfield (sir harry), 57. farinelli (miss), 38. flaugergues (h.), 51, 119. fleming (miss), 42. fourier (j.), 124. frauenhofer (j.), 195. galileo, 50, 135. george iii., 64, 77, 124, 126. griesbach (george), 63. griesbachs (the), 62, 106. hansen (p. a.), 142. hastings (c. s.), 119. heberden (dr.), 64. helmholtz (h.), 188. herschel (abraham) [1651-1718], 6. herschel (alexander) [1745-1821], 10, 12, 14, 15, 35, 38, 41, 57, 61, 62, 66, 72, 73, 114. herschel (benjamin), 7. herschel (carolina) [1750-1848], 2, 10, 11, 12, 16, 23, 29, 33, 41, 43, 68; discovers five comets, 69, 70, 78, 83, 103, 105, 112, 113, 114, 115. herschel (carolina), her _memoir_ quoted, 2, 9, 13, 23, 29, 31, 34, 36, 41, 57, 61, 63, 64, 65, 70, 74. herschel (dietrich), 9, 10, 11, 29, 42, 114. herschel (eusebius), 7. herschel (hans) [_circa_ 1600], 6. herschel (isaac) [1707-1767], 7, 8, 29. herschel (jacob) [1734-1792], 10, 11, 16, 23, 30. herschel (sir john frederick william) [1792-1871], 80, 103, 105, 114, 126, 127, 143, 203. herschel (lady), 80, 102, 103, 105, 114. herschel (major john), 2. herschel (mrs. mary cornwallis), 2. herschel (sophia elizabeth), b. 1733, married griesbach, 10. herschel (william), born 1738, november 15; 10. oboist in the band of the guards (1755), and goes to england for the first time, returning in 1756, 16. deserts from the guards and goes to england (1757), 17. organizes the band of the durham militia (1760), 18. leaves the band and lives with dr. miller, 19. leads the public concerts at wakefield and halifax, 20. organist at halifax (1765), 22. organist of the octagon chapel at bath (1766), 24. his musical writings, 26. studies smith's harmonies and optics, 28. visits hanover, august, 1772, 32. hires a small telescope, 37. makes his first telescope (1774), 38. visits hanover (1775?), 42. 1st review of the heavens, 39, 73. 2d review of the heavens, 73. 3d review of the heavens (1783), 73. 4th review of the heavens (1785), 74. manufacture of telescopes, 40, 59, 75, 77, 120, 121, 122, 123, 124, 125, 126, 127. moves to 19 new king st., bath, 43. conducts oratorios of handel, 43. begins astronomical _measures_ (1779), 44. joins philosophical society of bath, 45. first published scientific writing (1779), 46. first communication to the royal society (1780), 47. discovery of _uranus_ (1781, march 13), 49. its effect on his career, 53. elected a member of the royal society (1781), and receives the copley medal, 56. attempts a thirty-foot reflector, 59. goes to london, 1782 (may, june, july), 61. appointed royal astronomer (£200), 1782, 67. removes to datchet, 1782, august 1, 67. his assiduity, 72, 77, 79, 81. his mechanical genius, 14, 41, 121. cost of his telescopes, 77. marries mrs. john pitt, _née_ baldwin (1783), 80. only child born (1792), 80. removes to slough (1786), 81. ll.d. (_oxon._), 1786, 47. his account of the discovery of _uranus_ (1781, march 13), 4. discovers two satellites to _uranus_, 1787, jan. 11, 84. discovers two satellites to _saturn_, 1789, august-september, 125. invents machines for making reflectors (1788), 41. began forty-foot telescope, 1785, finished it, 1789, 121. biographical letter (1783), 3. list of published portraits of him, 232. value of his sister's assistance to him, 34. letters to carolina herschel, 61, 63, 64, 114. his personal character (1786-1800), 100 _et seq._ his relations to his cotemporaries, 85, 86, 87, 91, 94, 95, 96, 97, 98, 99. list of writings relating to him and to his works, 225. his literary skill, 45. examples of his style, 83 _et seq._ failure of health, 112 _et seq._ created a knight of the royal hanoverian guelphic order (1816), 115. herschel (sir william), first president of the royal astronomical society (1821), 115. his will, 114. his death, august 25th, 1822, 116. his epitaph, 117. list of his scientific writings, 215. review of his scientific labors, 118. the improvement of telescopes and apparatus, 121. the relative brightness of the stars; variable stars, 130. researches on double stars, 134. researches on planets and satellites, 140. researches on the nature of the sun, 145, 186, 198. the motion of the solar system in space, 149. researches on the construction of the heavens, 154. scale of celestial measures; distances of the stars, 170. researches on light, heat, etc., 176. researches on the dimensions of the stars, 193. on the spectra of the fixed stars, 195. on the variable emission of light and heat from the sun, 198. researches on nebulæ and clusters, 202. huyghens (c.), 50, 189. king george iii., 64, 77, 124, 126. lacaille (n. l.), 156, 202. lalande (jerome), 28, 124, 156. lambert (j. h.), 153. lassell (w.), 143. lee (miss), 61. lichtenberg (herr), 3. lind (dr. and mrs.), 69. long (dr.), 135. magellan (herr), 3, 78. maskelyne (nevil), 5, 51, 57, 62, 63, 150, 153. mayer (christian), 94, 153. melloni (m.), 186. messier (c.), 202. michell (john), 52, 94, 137, 156. miller (dr.), 19, 20, 21, 22. monson (mrs.), 115. moritzen (anna ilse), m. isaac herschel, 7, 8. napoleon i., 108, 111. newton (sir isaac), 189, 190, 191, 192. olbers (william), 95. pabrich (cappelmeister), 7. palmerston (lord), 64. piazzi (joseph), 75, 95. pierce (charles s.), 132. pigott (j.), 119. poggendorff (j. g.), 188. ronzoni (signor), 59. rosse (lord), 122, 207. savary (m.), 139. secchi (angelo), 195, 196. scheiner (c.), 199. schroeter (j. h.), 51, 77, 91, 92, 93. schwabe (h.), 201. short (james), 120. smith (dr. robert), 28. snetzler (herr), 20, 21. struve (otto von), 129. thomson (thomas), 95. verdet (e.), 188. wainwright (dr.), 20. walsh (colonel), 62. watson (sir william), 44, 58, 60, 64, 65, 66, 67, 75, 76. watt (james), 106. weld (r.), 126. wilson (alexander), 52, 94, 146. zach (baron von), 69. the end. start of transcriber's notes: i have used [alpha] to represent the greek letter used in the text. page line in the original text, left as is. 227 3 übersetzt 231 29 uebersetzt 18 24 biographie universelle des musiciens 226 24 biographie universelle des musiciens 231 33 koenigsberg, 1791. 8vo. 226 9 königsberger allgemeine zeitung 195 4 fraunhofer 235 index frauenhofer (j.), 195. 226 29 vol. (all other occurances are) vol. 238 index ronzoni (signor), 59. 58 26 ronzini original page line original text replaced with 65 23 ornamented. ornamented." 117 31 [c] for letter c reversed ci[c]i[c]cccxxii 216 25 den 18. may den 18. mai 219 23 suppl. band., p. 238. suppl. band, p. 238. end of transcriber's notes: proofreading team. [illustration: maria mitchell] maria mitchell life, letters, and journals compiled by phebe mitchell kendall illustrated 1896 contents chapter i the parents--home life--education, teachers, books--astronomical instruments--solar eclipse of 1831--teaching--appointment as librarian of nantucket atheneum--friendships for young people--extracts from diary, 1855--music--the piano--society--story-telling--housework--extract from diary, 1854 chapter ii "sweeping" the heavens--discovery of the comet, 1847--frederick vi. and the comet--letters from g. p. bond and hon. edward everett--admiral smyth--american academy--american association for the advancement of science--extract from diary, 1855--dorothea dix--esther--divers extracts from diary, 1853, 1854--comet of 1854--computations for comet--visit to cape cod--sandwich and plymouth--pilgrim hall--rev. james freeman clarke--accidents in observing chapter iii wires in the transit instrument--deacon greele--smithsonian fund--"doing"--rachel in "phèdre" and "adrienne"--emerson--the hard winter chapter iv southern tour--chicago--st. louis--scientific academy of st. louis--dr. pope--dr. seyffarth--mississippi river--sand-bars--cherry blossoms--eclipse of sun--natchez--new orleans--slave market--negro church--the "peculiar institution"--bible--judge smith--travelling without escort--savannah--rice plantations--negro children--miss murray--charleston--drive--condition of slaves--old buildings--miss rutledge--mr. capers--class meeting--hospitality--mrs. holbrook--miss pinckney--manners--portraits--miss pinckney's father--george washington--augusta--nashville--mrs. fogg--mrs. polk--charles sumner--mammoth cave--chattanooga chapter v first european tour--liverpool--london--rev. james martineau--mr. john taylor--mr. lassell--liverpool observatory--the hawthornes--shop-keepers and waiters--greenwich observatory--sir george airy--visits to greenwich--herr struvé's mission to england--dinner party--general sabine--westminster abbey--newton's monument--british museum--four great men--st. paul's--dr. johnson--opera--aylesbury--admiral smyth's family--amateur astronomers--hartwell house--dr. lee chapter vi cambridge--dr. whewell--table conversation--professor challis--professor adams--customs--professor sedgwick--caste--king's chapel--fellows-ambleside--coniston waters--the lakes--miss southey--collingwood--letter to her father--herschels--london rout--professor stokes--dr. arnott--edinboro'--observatory--glasgow observatory--professor nichol--dungeon ghyll--english language--english and americans--boys and beggars chapter vii adams and leverrier--the discovery of the planet neptune--extract from papers--professor bond, of cambridge, mass.--paris--imperial observatory--mons. and mme. leverrier--reception at leverrier's--rooms in observatory--rome--impressions--apartments in rome and paris--customs--holy week--vespers at st. peter's--women--frederika bremer--paul akers--harriet hosmer--collegio romano--father secchi--galileo--visit to the roman observatory--permission from cardinal antonelli--spectroscope chapter viii mrs. somerville--berlin--humboldt--mrs. mitchell's illness and death--removal to lynn, mass.--telescope presented to miss mitchell by elizabeth peabody and others--letters from admiral smyth--colors of stars--extract from letter to a friend--san marino medal--other extracts chapter ix life at vassar college--anxious mammas--faculty meetings--president hill--professor peirce--burlington, ia., and solar eclipse--classes at vassar--professor mitchell and her pupils--extracts from diary--aids --scholarships--address to her students--imagination in science--"i am but a woman"--maria mitchell endowment fund--emperor of brazil--president raymond's death--dome parties--comet, 1881--the apple-tree--"honor girls"--mr. matthew arnold chapter x second visit to europe--russia--extracts from diary and letters--custom-house peculiarities--russian railways--domes--russian thermometers and calendars--the drosky and drivers--observatory at pulkova--herr struvé--scientific position of russia--language-religion--democracy of the church--government--a russian family--london, 1873--frances power cobbe--bookstores in london--glasgow college for girls chapter xi papers--science--eclipse of 1878, denver, colorado--colors of stars chapter xii religious matters--president taylor's remarks--sermons--george macdonald--rev. dr. peabody--dr. lyman abbott--professor henry--meeting of the american scientific association at saratoga--professor peirce-concord school of philosophy--emerson--miss peabody--dr. harris--easter flowers--whittier--rich days--cooking schools--anecdotes chapter xiii letter-writing--woman suffrage--membership in various societies.--women's congress at syracuse, n.y.--picnic at medfield, mass.--degrees from different colleges--published papers.--failure in health--resigns her position at vassar college--letters from various persons--death--conclusion appendix introductory note by hon. edward everett correspondence relative to the danish medal chapter i 1818-1846 birth--parents--home surroundings and early life maria mitchell was born on the island of nantucket, mass., aug. 1, 1818. she was the third child of william and lydia [coleman] mitchell. her ancestors, on both sides, were quakers for many generations; and it was in consequence of the intolerance of the early puritans that these ancestors had been obliged to flee from the state of massachusetts, and to settle upon this island, which, at that time, belonged to the state of new york. for many years the quakers, or friends, as they called themselves, formed much the larger part of the inhabitants of nantucket, and thus were enabled to crystallize, as it were, their own ideas of what family and social life should be; and although in course of time many "world's people" swooped down and helped to swell the number of islanders, they still continued to hold their own methods, and to bring up their children in accordance with their own conceptions of "divine light." mr. and mrs. mitchell were married during the war of 1812; the former lacking one week of being twenty-one years old, and the latter being a few months over twenty. the people of nantucket by their situation endured many hardships during this period; their ships were upon the sea a prey to privateers, and communication with the mainland was exposed to the same danger, so that it was difficult to obtain such necessaries of life as the island could not furnish. there were still to be seen, a few years ago, the marks left on the moors, where fields of corn and potatoes had been planted in that trying time. so the young couple began their housekeeping in a very simple way. mr. mitchell used to describe it as being very delightful; it was noticed that mrs. mitchell never expressed herself on the subject,--it was she, probably, who had the planning to do, to make a little money go a great way, and to have everything smooth and serene when her husband came home. mrs. mitchell was a woman of strong character, very dignified, honest almost to an extreme, and perfectly self-controlled where control was necessary. she possessed very strong affections, but her self-control was such that she was undemonstrative. she kept a close watch over her children, was clearheaded, knew their every fault and every merit, and was an indefatigable worker. it was she who looked out for the education of the children and saw what their capacities were. mr. mitchell was a man of great suavity and gentleness; if left to himself he would never have denied a single request made to him by one of his children. his first impulse was to gratify every desire of their hearts, and if it had not been for the clear head of the mother, who took care that the household should be managed wisely and economically, the results might have been disastrous. the father had wisdom enough to perceive this, and when a child came to him, and in a very pathetic and winning way proffered some request for an unusual indulgence, he generally replied, "yes, if mother thinks best." mr. mitchell was very fond of bright colors; as they were excluded from the dress of friends, he indulged himself wherever it was possible. if he were buying books, and there was a variety of binding, he always chose the copies with red covers. even the wooden framework of the reflecting telescope which he used was painted a brilliant red. he liked a gay carpet on the floor, and the walls of the family sitting-room in the house on vestal street were covered with paper resplendent with bunches of pink roses. suspended by a cord from the ceiling in the centre of this room was a glass ball, filled with water, used by mr. mitchell in his experiments on polarization of light, flashing its dancing rainbows about the room. at the back of this house was a little garden, full of gay flowers: so that if the garb of the young mitchells was rather sombre, the setting was bright and cheerful, and the life in the home was healthy and wide-awake. when the hilarity became excessive the mother would put in her little check, from time to time, and the father would try to look as he ought to, but he evidently enjoyed the whole. as mr. mitchell was kind and indulgent to his children, so he was the sympathetic friend and counsellor of many in trouble who came to him for help or advice. as he took his daily walk to the little farm about a mile out of town, where, for an hour or two he enjoyed being a farmer, the people would come to their doors to speak to him as he passed, and the little children would run up to him to be patted on the head. he treated animals in the same way. he generally kept a horse. his children complained that although the horse was good when it was bought, yet as mr. mitchell never allowed it to be struck with a whip, nor urged to go at other than a very gentle trot, the horse became thoroughly demoralized, and was no more fit to drive than an old cow! there was everything in the home which could amuse and instruct children. the eldest daughter was very handy at all sorts of entertaining occupations; she had a delicate sense of the artistic, and was quite skilful with her pencil. the present kindergarten system in its practice is almost identical with the home as it appeared in the first half of this century, among enlightened people. there is hardly any kind of handiwork done in the kindergarten that was not done in the mitchell family, and in other families of their acquaintance. the girls learned to sew and cook, just as they learned to read,--as a matter of habit rather than of instruction. they learned how to make their own clothes, by making their dolls' clothes,--and the dolls themselves were frequently home-made, the eldest sister painting the faces much more prettily than those obtained at the shops; and there was a great delight in gratifying the fancy, by dressing the dolls, not in quaker garb, but in all of the most brilliant colors and stylish shapes worn by the ultra-fashionable. there were always plenty of books, and besides those in the house there was the atheneum library, which, although not a free library, was very inexpensive to the shareholders. there was another very striking difference between that epoch and the present. the children of that day were taught to value a book and to take excellent care of it; as an instance it may be mentioned that one copy of colburn's "algebra" was used by eight children in the mitchell family, one after the other. the eldest daughter's name was written on the inside of the cover; seven more names followed in the order of their ages, as the book descended. with regard to their reading, the mother examined every book that came into the house. of course there were not so many books published then as now, and the same books were read over and over. miss edgeworth's stories became part of their very lives, and young's "night thoughts," and the poems of cowper and bloomfield were conspicuous objects on the bookshelves of most houses in those days. mr. mitchell was very apt, while observing the heavens in the evening, to quote from one or the other of these poets, or from the bible. "an undevout astronomer is mad" was one of his favorite quotations. among the poems which maria learned in her childhood, and which was repeatedly upon her lips all through her life, was, "the spacious firmament on high." in her latter years if she had a sudden fright which threatened to take away her senses she would test her mental condition by repeating that poem; it is needless to say that she always remembered it, and her nerves instantly relapsed into their natural condition. the lives of maria mitchell and her numerous brothers and sisters were passed in simplicity and with an entire absence of anything exciting or abnormal. the education of their children is enjoined upon the parents by the "discipline," and in those days at least the parents did not give up all the responsibility in that line to the teachers. in maria mitchell's childhood the children of a family sat around the table in the evenings and studied their lessons for the next day,--the parents or the older children assisting the younger if the lessons were too difficult. the children attended school five days in the week,--six hours in the day,--and their only vacation was four weeks in the summer, generally in august. the idea that children over-studied and injured their health was never promulgated in that family, nor indeed in that community; it seems to be a notion of the present half-century. maria's first teacher was a lady for whom she always felt the warmest affection, and in her diary, written in her later years, occurs this allusion to her: "i count in my life, outside of family relatives, three aids given me on my journey; they are prominent to me: the woman who first made the study-book charming; the man who sent me the first hundred dollars i ever saw, to buy books with; and another noble woman, through whose efforts i became the owner of a telescope; and of these, the first was the greatest." as a little girl, maria was not a brilliant scholar; she was shy and slow; but later, under her father's tuition, she developed very rapidly. after the close of the war of 1812, when business was resumed and the town restored to its normal prosperity, mr. mitchell taught school,--at first as master of a public school, and afterwards in a private school of his own. maria attended both of these schools. mr. mitchell's pupils speak of him as a most inspiring teacher, and he always spoke of his experiences in that capacity as very happy. when her father gave up teaching, maria was put under the instruction of mr. cyrus peirce, afterwards principal of the first normal school started in the united states. mr. peirce took a great interest in maria, especially in developing her taste for mathematical study, for which she early showed a remarkable talent. the books which she studied at the age of seventeen, as we know by the date of the notes, were bridge's "conic sections," hutton's "mathematics," and bowditch's "navigator." at that time prof. benjamin peirce had not published his "explanations of the navigator and almanac," so that maria was obliged to consult many scientific books and reports before she could herself construct the astronomical tables. mr. mitchell, on relinquishing school-teaching, was appointed cashier of the pacific bank; but although he gave up teaching, he by no means gave up studying his favorite science, astronomy, and maria was his willing helper at all times. mr. mitchell from his early youth was an enthusiastic student of astronomy, at a time, too, when very little attention was given to that study in this country. his evenings, when pleasant, were spent in observing the heavens, and to the children, accustomed to seeing such observations going on, the important study in the world seemed to be astronomy. one by one, as they became old enough, they were drafted into the service of counting seconds by the chronometer, during the observations. some of them took an interest in the thing itself, and others considered it rather stupid work, but they all drank in so much of this atmosphere, that if any one had asked a little child in this family, "who was the greatest man that ever lived?" the answer would have come promptly, "herschel." maria very early learned the use of the sextant. the chronometers of all the whale ships were brought to mr. mitchell, on their return from a voyage, to be "rated," as it was called. for this purpose he used the sextant, and the observations were made in the little back yard of the vestal-street home. there was also a clumsy reflecting telescope made on the herschelian plan, but of very great simplicity, which was put up on fine nights in the same back yard, when the neighbors used to flock in to look at the moon. afterwards mr. mitchell bought a small dolland telescope, which thereafter, as long as she lived, his daughter used for "sweeping" purposes. after their removal to the bank building there were added to these an "altitude and azimuth circle," loaned to mr. mitchell by west point academy, and two transit instruments. a little observatory for the use of the first was placed on the roof of the bank building, and two small buildings were erected in the yard for the transits. there was also a much larger and finer telescope loaned by the coast survey, for which service mr. mitchell made observations. at the time when maria mitchell showed a decided taste for the study of astronomy there was no school in the world where she could be taught higher mathematics and astronomy. harvard college, at that time, had no telescope better than the one which her father was using, and no observatory except the little octagonal projection to the old mansion in cambridge occupied by the late dr. a.p. peabody. however, every one will admit that no school nor institution is better for a child than the home, with an enthusiastic parent for a teacher. at the time of the annular eclipse of the sun in 1831 the totality was central at nantucket. the window was taken out of the parlor on vestal street, the telescope, the little dolland, mounted in front of it, and with maria by his side counting the seconds the father observed the eclipse. maria was then twelve years old. at sixteen miss mitchell left mr. peirce's school as a pupil, but was retained as assistant teacher; she soon relinquished that position and opened a private school on traders' lane. this school too she gave up for the position of librarian of the nantucket atheneum, which office she held for nearly twenty years. this library was open only in the afternoon, and on saturday evening. the visitors were comparatively few in the afternoon, so that miss mitchell had ample leisure for study,--an opportunity of which she made the most. her visitors in the afternoon were elderly men of leisure, who enjoyed talking with so bright a girl on their favorite hobbies. when they talked miss mitchell closed her book and took up her knitting, for she was never idle. with some of these visitors the friendship was kept up for years. it was in this library that she found la place's "mécanique céleste," translated by her father's friend, dr. bowditch; she also read the "theoria motus," of gauss, in its original latin form. in her capacity as librarian miss mitchell to a large extent controlled the reading of the young people in the town. many of them on arriving at mature years have expressed their gratitude for the direction in which their reading was turned by her advice. miss mitchell always had a special friendship for young girls and boys. many of these intimacies grew out of the acquaintance made at the library,--the young girls made her their confidante and went to her for sympathy and advice. the boys, as they grew up, and went away to sea, perhaps, always remembered her, and made a point, when they returned in their vacations, of coming to tell their experiences to such a sympathetic listener. "april 18, 1855. a young sailor boy came to see me to-day. it pleases me to have these lads seek me on their return from their first voyage, and tell me how much they have learned about navigation. they always say, with pride, 'i can take a lunar, miss mitchell, and work it up!' "this boy i had known only as a boy, but he has suddenly become a man and seems to be full of intelligence. he will go once more as a sailor, he says, and then try for the position of second mate. he looked as if he had been a good boy and would make a good man. "he said that he had been ill so much that he had been kept out of temptation; but that the forecastle of a ship was no place for improvement of mind or morals. he said the captain with whom he came home asked him if he knew me, because he had heard of me. i was glad to find that the captain was a man of intelligence and had been kind to the boy." miss mitchell was an inveterate reader. she devoured books on all subjects. if she saw that boys were eagerly reading a certain book she immediately read it; if it were harmless she encouraged them to read it; if otherwise, she had a convenient way of _losing_ the book. in november, when the trustees made their annual examination, the book appeared upon the shelf, but the next day after it was again lost. at this time nantucket was a thriving, busy town. the whale-fishery was a very profitable business, and the town was one of the wealthiest in the state. there was a good deal of social and literary life. in a friend's family neither music nor dancing was allowed. mr. and mrs. mitchell were by no means narrow sectarians, but they believed it to be best to conform to the rules of friends as laid down in the "discipline." george fox himself, the founder of the society, had blown a blast against music, and especially instrumental music in churches. it will be remembered that the methodists have but recently yielded to the popular demand in this respect, and have especially favored congregational singing. it is most likely that george fox had no ear for music himself, and thus entailed upon his followers an obligation from which they are but now freeing themselves. there was plenty of singing in the mitchell family, and the parents liked it, especially the father, who, when he sat down in the evening with the children, would say, "now sing something." but there could be no instruction in singing; the children sang the songs that they picked up from their playmates. however, one of the daughters bought a piano, and maria's purse opened to help that cause along. it would not have been proper for mr. mitchell to help pay for it, but he took a great interest in it, nevertheless. so indeed did the mother, but she took care not to express herself outwardly. the piano was kept in a neighboring building not too far off to be heard from the house. maria had no ear for music herself, but she was always to be depended upon to take the lead in an emergency, so the sisters put their heads together and decided that the piano must be brought into the house. when they had made all the preparations the father and mother were invited to take tea with their married daughter, who lived in another part of the town and had been let into the secret. the piano was duly removed and placed in an upper room called the "hall," where mr. mitchell kept the chronometers, where the family sewing was done, and where the larger part of the books were kept,--a beautiful room, overlooking "the square," and a great gathering-place for all their young friends. when the piano was put in place, the sisters awaited the coming of the parents. maria stationed herself at the foot of the stairs, ready to meet them as they entered the front door; another, half-way between, was to give the signal to a third, who was seated at the piano. the footsteps were heard at the door, the signal was given; a lively tune was started, and maria confronted the parents as they entered. "what's that?" was the exclamation. "well," said maria, soothingly, "we've had the piano brought over." "why, of all things!" exclaimed the mother. the father laid down his hat, walked immediately upstairs, entered the hall, and said, "come, daughter, play something lively!" so that was all. but that was not all for mr. mitchell; he had broken the rules accepted by the friends, and it was necessary for some notice to be taken of it, so a dear old friend and neighbor came to deal with him. now, to be "under dealings," as it is called, was a very serious matter,--to be spoken of only under the breath, in a half whisper. "i hear that thee has a piano in thy house," said the old friend. "yes, my daughters have," was the reply. "but it is in thy house," pursued the friend. "yes; but my home is my children's home as well as mine," said mr. mitchell, "and i propose that they shall not be obliged to go away from home for their pleasures. i don't play on the piano." it so happened that mr. mitchell held the property of the "monthly meeting" in his hands at the time, and it was a very improper thing for the accredited agent of the society to be "under dealings," as mr. mitchell gently suggested. this the friend had not thought of, and so he said, "well, william, perhaps we'd better say no more about it." when the father came home after this interview he could not keep it to himself. if it had been the mother who was interviewed she would have kept it a profound secret,--because she would not have liked to have her children get any fun out of the proceedings of the old friend. but mr. mitchell told the story in his quiet way, the daughters enjoyed it, and declared that the piano was placed upon a firm foothold by this proceeding. the news spread abroad, and several other young quaker girls eagerly seized the occasion to gratify their musical longings in the same direction. [footnote: it is pleasant to note that this objection to music among friends is a thing of the past, and that the friends' school at providence, r.i., which is under the control of the "new england yearly meeting of friends," has music in its regular curriculum.] few women with scientific tastes had the advantages which surrounded miss mitchell in her own home. her father was acquainted with the most prominent scientific men in the country, and in his hospitable home at nantucket she met many persons of distinction in literature and science. she cared but little for general society, and had always to be coaxed to go into company. later in life, however, she was much more socially inclined, and took pleasure in making and receiving visits. she could neither dance nor sing, but in all amusements which require quickness and a ready wit she was very happy. she was very fond of children, and knew how to amuse them and to take care of them. as she had half a dozen younger brothers and sisters, she had ample opportunity to make herself useful. she was a capital story-teller, and always had a story on hand to divert a wayward child, or to soothe the little sister who was lying awake, and afraid of the dark. she wrote a great many little stories, printed them with a pen, and bound them in pretty covers. most of them were destroyed long ago. maria took her part in all the household work. she knew how to do everything that has to be done in a large family where but one servant is kept, and she did everything thoroughly. if she swept a room it became clean. she might not rearrange the different articles of furniture in the most artistic manner, but everything would be clean, and there would be nothing left crooked. if a chair was to be placed, it would be parallel to something; she was exceedingly sensitive to a line out of the perpendicular, and could detect the slightest deviation from that rule. she had also a sensitive eye in the matter of color, and felt any lack of harmony in the colors worn by those about her. maria was always ready to "bear the brunt," and could at any time be coaxed by the younger children to do the things which they found difficult or disagreeable. the two youngest children in the family were delicate, and the special care of the youngest sister devolved upon maria, who knew how to be a good nurse as well as a good playfellow. she was especially careful of a timid child; she herself was timid, and, throughout her life, could never witness a thunder-storm with any calmness. on one of those occasions so common in an american household, when the one servant suddenly takes her leave, or is summarily dismissed, miss mitchell describes her part of the family duties: "oct. 21, 1854. this morning i arose at six, having been half asleep only for some hours, fearing that i might not be up in time to get breakfast, a task which i had volunteered to do the preceding evening. it was but half light, and i made a hasty toilet. i made a fire very quickly, prepared the coffee, baked the graham bread, toasted white bread, trimmed the solar lamp, and made another fire in the dining-room before seven o'clock. "i always thought that servant-girls had an easy time of it, and i still think so. i really found an hour too long for all this, and when i rang the bell at seven for breakfast i had been waiting fifteen minutes for the clock to strike. "i went to the atheneum at 9.30, and having decided that i would take the newark and cambridge places of the comet, and work them up, i did so, getting to the three equations before i went home to dinner at 12.30. i omitted the corrections of parallax and aberrations, not intending to get more than a rough approximation. i find to my sorrow that they do not agree with those from my own observations. i shall look over them again next week. "at noon i ran around and did up several errands, dined, and was back again at my post by 1.30. then i looked over my morning's work,--i can find no mistake. i have worn myself thin trying to find out about this comet, and i know very little now in the matter. "i saw, in looking over cooper, elements of a comet of 1825 which resemble what i get out for this, from my own observations, but i cannot rely upon my own. "i saw also, to-day, in the 'monthly notices,' a plan for measuring the light of stars by degrees of illumination,--an idea which had occurred to me long ago, but which i have not practised. "october 23. yesterday i was again reminded of the remark which mrs. stowe makes about the variety of occupations which an american woman pursues. "she says it is this, added to the cares and anxieties, which keeps them so much behind the daughters of england in personal beauty. "and to-day i was amused at reading that one of her party objected to the introduction of waxed floors into american housekeeping, because she could seem to see herself down on her knees doing the waxing. "but of yesterday. i was up before six, made the fire in the kitchen, and made coffee. then i set the table in the dining-room, and made the fire there. toasted bread and trimmed lamps. rang the breakfast bell at seven. after breakfast, made my bed, and 'put up' the room. then i came down to the atheneum and looked over my comet computations till noon. before dinner i did some tatting, and made seven button-holes for k. i dressed and then dined. came back again to the atheneum at 1.30, and looked over another set of computations, which took me until four o'clock. i was pretty tired by that time, and rested by reading 'cosmos.' lizzie e. came in, and i gossiped for half an hour. i went home to tea, and that over, i made a loaf of bread. then i went up to my room and read through (partly writing) two exercises in german, which took me thirty-five minutes. "it was stormy, and i had no observing to do, so i sat down to my tatting. lizzie e. came in and i took a new lesson in tatting, so as to make the pearl-edged. i made about half a yard during the evening. at a little after nine i went home with lizzie, and carried a letter to the post-office. i had kept steadily at work for sixteen hours when i went to bed." chapter ii 1847-1854 miss mitchell's comet--extracts from diary--the comet miss mitchell spent every clear evening on the house-top "sweeping" the heavens. no matter how many guests there might be in the parlor, miss mitchell would slip out, don her regimentals as she called them, and, lantern in hand, mount to the roof. on the evening of oct. 1, 1847, there was a party of invited guests at the mitchell home. as usual, maria slipped out, ran up to the telescope, and soon returned to the parlor and told her father that she thought she saw a comet. mr. mitchell hurried upstairs, stationed himself at the telescope, and as soon as he looked at the object pointed out by his daughter declared it to be a comet. miss mitchell, with her usual caution, advised him to say nothing about it until they had observed it long enough to be tolerably sure. but mr. mitchell immediately wrote to professor bond, at cambridge, announcing the discovery. on account of stormy weather, the mails did not leave nantucket until october 3. frederick vi., king of denmark, had offered, dec. 17, 1831, a gold medal of the value of twenty ducats to the first discoverer of a telescopic comet. the regulations, as revised and amended, were republished, in april, 1840, in the "astronomische nachrichten." when this comet was discovered, the king who had offered the medal was dead. the son, frederick vii., who had succeeded him, had not the interest in science which belonged to his father, but he was prevailed upon to carry out his father's designs in this particular case. the same comet had been seen by father de vico at rome, on october 3, at 7.30 p.m., and this fact was immediately communicated by him to professor schumacher, at altona. on the 7th of october, at 9.20 p.m., the comet was observed by mr. w.r. dawes, at kent, england, and on the 11th it was seen by madame rümker, the wife of the director of the observatory at hamburg. the following letter from the younger bond will show the cordial relations existing between the observatory at cambridge and the smaller station at nantucket: cambridge, oct. 20, 1847. dear maria: there! i think that is a very amiable beginning, considering the way in which i have been treated by you! if you are going to find any more comets, can you not wait till they are announced by the proper authorities? at least, don't kidnap another such as this last was. if my object were to make you fear and tremble, i should tell you that on the evening of the 30th i was sweeping within a few degrees of your prize. i merely throw out the hint for what it is worth. it has been very interesting to watch the motion of this comet among the stars with the great refractor; we could almost see it move. an account of its passage over the star mentioned by your father when he was here, would make an interesting notice for one of the foreign journals, which we would readily forward.... [here follow mr. bond's observations.] respectfully, your obedient servant, g. p. bond. hon. edward everett, who at that time was president of harvard college, took a great interest in the matter, and immediately opened a correspondence with the proper authorities, and sent a notice of the discovery to the "astronomische nachrichten." the priority of miss mitchell's discovery was immediately admitted throughout europe. the king of denmark very promptly referred the matter to professor schumacher, who reported in favor of granting the medal to miss mitchell, and the medal was duly struck off and forwarded to mr. everett. among european astronomers who urged miss mitchell's claim was admiral smyth, whom she knew through his "celestial cycle," and who later, on her visit to england, became a warm personal friend. madame rümker, also, sent congratulations. mr. everett announced the receipt of the medal to miss mitchell in the following letter: cambridge, march 29, 1849. my dear miss mitchell: i have the pleasure to inform you that your medal arrived by the last steamer; it reached me by mail, yesterday afternoon. i went to boston this morning, hoping to find you at the adams house, to put it into your own hand. as your return to nantucket prevented this, i, of course, retain it, subject to your orders, not liking to take the risk again of its transmission by mail. having it in this way in my hand, i have taken the liberty to show it to some friends, such as w.c. bond, professor peirce, the editors of the "transcript," and the members of my family,--which i hope you will pardon. i remain, my dear miss mitchell, with great regard, very faithfully yours, edward everett.[footnote: see appendix.] in 1848 miss mitchell was elected to membership by the "american academy of arts and sciences," unanimously; she was the first and only woman ever admitted. in the diploma the printed word "fellow" is erased, and the words "honorary member" inserted by dr. asa gray, who signed the document as secretary. some years later, however, her name is found in the list of fellows of this academy, also of the american institute and of the american association for the advancement of science. for many years she attended the annual conventions of this last-mentioned association, in which she took great interest. the extract below refers to one of these meetings, probably that of 1855: "august 23. it is really amusing to find one's self lionized in a city where one has visited quietly for years; to see the doors of fashionable mansions open wide to receive you, which never opened before. i suspect that the whole corps of science laughs in its sleeves at the farce. "the leaders make it pay pretty well. my friend professor bache makes the occasions the opportunities for working sundry little wheels, pulleys, and levers; the result of all which is that he gets his enormous appropriations of $400,000 out of congress, every winter, for the maintenance of the united states coast survey. "for a few days science reigns supreme,--we are fêted and complimented to the top of our bent, and although complimenters and complimented must feel that it is only a sort of theatrical performance, for a few days and over, one does enjoy acting the part of greatness for a while! i was tired after three days of it, and glad to take the cars and run away. "the descent into a commoner was rather sudden. i went alone to boston, and when i reached out my free pass, the conductor read it through and handed it back, saying in a gruff voice, 'it's worth nothing; a dollar and a quarter to boston.' think what a downfall! the night before, and 'one blast upon my bugle horn were worth a hundred men!' now one man alone was my dependence, and that man looked very much inclined to put me out of the car for attempting to pass a ticket that in his eyes was valueless. of course i took it quietly, and paid the money, merely remarking, 'you will pass a hundred persons on this road in a few days on these same tickets.' "when i look back on the paper read at this meeting by mr. j---in his uncouth manner, i think when a man is thoroughly in earnest, how careless he is of mere _words!_" in 1849 miss mitchell was asked by the late admiral davis, who had just taken charge of the american nautical almanac, to act as computer for that work,--a proposition to which she gladly assented, and for nineteen years she held that position in addition to her other duties. this, of course, made a very desirable increase to her income, but not necessarily to her expenses. the tables of the planet venus were assigned to her. in this year, too, she was employed by professor bache, of the united states coast survey, in the work of an astronomical party at mount independence, maine. "1853. i was told that miss dix wished to see me, and i called upon her. it was dusk, and i did not at once see her; her voice was low, not particularly sweet, but very gentle. she told me that she had heard professor henry speak of me, and that professor henry was one of her best friends, the truest man she knew. when the lights were brought in i looked at her. she must be past fifty, she is rather small, dresses indifferently, has good features in general, but indifferent eyes. she does not brighten up in countenance in conversing. she is so successful that i suppose there must be a hidden fire somewhere, for heat is a motive power, and her cold manners could never move legislatures. i saw some outburst of fire when mrs. hale's book was spoken of. it seems mrs. hale wrote to her for permission to publish a notice of her, and was decidedly refused; another letter met with the same answer, yet she wrote a 'life' which miss dix says is utterly false. "in her general sympathy for suffering humanity, miss dix seems neglectful of the individual interest. she has no family connection but a brother, has never had sisters, and she seemed to take little interest in the persons whom she met. i was surprised at her feeling any desire to see me. she is not strikingly interesting in conversation, because she is so grave, so cold, and so quiet. i asked her if she did not become at times weary and discouraged; and she said, wearied, but not discouraged, for she had met with nothing but success. there is evidently a strong will which carries all before it, not like the sweep of the hurricane, but like the slow, steady, and powerful march of the molten lava. "it is sad to see a woman sacrificing the ties of the affections even to do good. i have no doubt miss dix does much good, but a woman needs a home and the love of other women at least, if she lives without that of man." the following entry was made many years after:-"august, 1871. i have just seen miss dix again, having met her only once for a few minutes in all the eighteen years. she listened to a story of mine about some girls in need, and then astonished me by an offer she made me." "feb. 15, 1853. i think dr. hall [in his 'life of mary ware'] does wrong when he attempts to encourage the use of the _needle_. it seems to me that the needle is the chain of woman, and has fettered her more than the laws of the country. "once emancipate her from the 'stitch, stitch, stitch," the industry of which would be commendable if it served any purpose except the gratification of her vanity, and she would have time for studies which would engross as the needle never can. i would as soon put a girl alone into a closet to meditate as give her only the society of her needle. the art of sewing, so far as men learn it, is well enough; that is, to enable a person to _take the stitches_, and, if necessary, to make her own garments in a strong manner; but the dressmaker should no more be a universal character than the carpenter. suppose every man should feel it is his duty to do his own mechanical work of _all_ kinds, would society be benefited? would the work be well done? yet a woman is expected to know how to do all kinds of sewing, all kinds of cooking, all kinds of any _woman's_ work, and the consequence is that life is passed in learning these only, while the universe of truth beyond remains unentered. "may 11, 1853. i could not help thinking of esther [a much-loved cousin who had recently died] a few evenings since when i was observing. a meteor flashed upon me suddenly, very bright, very short-lived; it seemed to me that it was sent for me especially, for it greeted me almost the first instant i looked up, and was gone in a second,--it was as fleeting and as beautiful as the smile upon esther's face the last time i saw her. i thought when i talked with her about death that, though she could not come to me visibly, she might be able to influence my feelings; but it cannot be, for my faith has been weaker than ever since she died, and my fears have been greater." a few pages farther on in the diary appears this poem: "esther "living, the hearts of all around sought hers as slaves a throne; dying, the reason first we found- the fulness of her own. "she gave unconsciously the while a wealth we all might share- to me the memory of the smile that last i saw her wear. "earth lost from out its meagre store a bright and precious stone; heaven could not be so rich before, but it has richer grown." "sept. 19, 1853. i am surprised to find the verse which i picked up somewhere and have always admired- "'oh, reader, had you in your mind such stores as silent thought can bring, oh, gentle reader, you would find a tale in everything'-belonging to wordsworth and to one of wordsworth's simple, i am almost ready to say _silly_, poems. i am in doubt what to think of wordsworth. i should be ashamed of some of his poems if i had written them myself, and yet there are points of great beauty, and lines which once in the mind will not leave it. "oct. 31, 1853. people have to learn sometimes not only how much the heart, but how much the head, can bear. my letter came from cambridge [the harvard observatory], and i had some work to do over. it was a wearyful job, but by dint of shutting myself up all day i did manage to get through with it. the good of my travelling showed itself then, when i was too tired to read, to listen, or to talk; for the beautiful scenery of the west was with me in the evening, instead of the tedious columns of logarithms. it is a blessed thing that these pictures keep in the mind and come out at the needful hour. i did not call them, but they seemed to come forth as a regulator for my tired brain, as if they had been set sentinel-like to watch a proper time to appear. "november, 1853. there is said to be no up or down in creation, but i think the _world_ must be _low_, for people who keep themselves constantly before it do a great deal of stooping! "dec. 8, 1853. last night we had the first meeting of the class in elocution. it was very pleasant, but my deficiency of ear was never more apparent to myself. we had exercises in the ascending scale, and i practised after i came home, with the family as audience. h. says my ear is competent only to vulgar hearing, and i cannot appreciate nice distinctions.... i am sure that i shall never say that if i had been properly educated i should have made a singer, a dancer, or a painter--i should have failed less, perhaps, in the last. ... coloring i might have been good in, for i do think my eyes are better than those of any one i know. "feb. 18, 1854. if i should make out a calendar by my feelings of fatigue, i should say there were six saturdays in the week and one sunday. "mr. ---somewhat ridicules my plan of reading milton with a view to his astronomy, but i have found it very pleasant, and have certainly a juster idea of milton's variety of greatness than i had before. i have filled several sheets with my annotations on the 'paradise lost,' which i may find useful if i should ever be obliged to teach, either as a schoolma'am or a lecturer. [footnote: this paper has been printed since miss mitchell's death in "poet-lore," june-july, 1894.] "march 2, 1854. i 'swept' last night two hours, by three periods. it was a grand night--not a breath of air, not a fringe of a cloud, all clear, all beautiful. i really enjoy that kind of work, but my back soon becomes tired, long before the cold chills me. i saw two nebulae in leo with which i was not familiar, and that repaid me for the time. i am always the better for open-air breathing, and was certainly meant for the wandering life of the indian. "sept. 12, 1854. i am just through with a summer, and a summer is to me always a trying ordeal. i have determined not to spend so much time at the atheneum another season, but to put some one in my place who shall see the strange faces and hear the strange talk. "how much talk there is about religion! giles [footnote: rev. henry giles.] i like the best, for he seems, like myself, to have no settled views, and to be religious only in feeling. he says he has no piety, but a great sense of infinity. "yesterday i had a shaker visitor, and to-day a catholic; and the more i see and hear, the less do i care about church doctrines. the catholic, a priest, i have known as an atheneum visitor for some time. he talked to-day, on my asking him some questions, and talked better than i expected. he is plainly full of intelligence, full of enthusiasm for his religion, and, i suspect, full of bigotry. i do not believe he will die a catholic priest. a young man of his temperament must find it hard to live without family ties, and i shall expect to hear, if i ever hear of him again, that some good little irish girl has made him forget his vows. "my visitors, in other respects, have been of the average sort. four women have been delighted to make my acquaintance--three men have thought themselves in the presence of a superior being; one offered me twenty-five cents because i reached him the key of the museum. one woman has opened a correspondence with me, and several have told me that they knew friends of mine; two have spoken of me in small letters to small newspapers; one said he didn't see me, and one said he did! i have become hardened to all; neither compliment nor quarter-dollar rouses any emotion. my fit of humility, which has troubled me all summer, is shaken, however, by the first cool breeze of autumn and the first walk taken without perspiration. "sept. 22, 1854. on the evening of the 18th, while 'sweeping,' there came into the field the two nebulae in ursa major, which i have known for many a year, but which to my surprise now appeared to be three. the upper one, as seen from an inverting telescope, appeared double-headed, like one near the dolphin, but much more decided than that, the space between the two heads being very plainly discernible and subtending a decided angle. the bright part of this object was clearly the old nebula--but what was the appendage? had the nebula suddenly changed? was it a comet, or was it merely a very fine night? father decided at once for the comet; i hesitated, with my usual cowardice, and forbade his giving it a notice in the newspaper. "i watched it from 8.30 to 11.30 almost without cessation, and was quite sure at 11.30 that its position had changed with regard to the neighboring stars. i counted its distance from the known nebula several times, but the whole affair was difficult, for there were flying clouds, and sometimes the nebula and comet were too indistinct to be definitely seen. "the 19th was cloudy and the 20th the same, with the variety of occasional breaks, through which i saw the nebula, but not the comet. "on the 21st came a circular, and behold mr. van arsdale had seen it on the 13th, but had not been sure of it until the 15th, on account of the clouds. "i was too well pleased with having really made the discovery to care because i was not first. "let the dutchman have the reward of his sturdier frame and steadier nerves! "especially could i be a christian because the 13th was cloudy, and more especially because i dreaded the responsibility of making the computations, _nolens volens_, which i must have done to be able to call it mine.... "i made observations for three hours last night, and am almost ill to-day from fatigue; still i have worked all day, trying to reduce the places, and mean to work hard again to-night. "sept. 25, 1854. i began to recompute for the comet, with observations of cambridge and washington, to-day. i have had a fit of despondency in consequence of being obliged to renounce my own observations as too rough for use. the best that can be said of my life so far is that it has been industrious, and the best that can be said of me is that i have not pretended to what i was not. "october 10. as soon as i had run through the computations roughly for the comet, so as to make up my mind that by my own observations (which were very wrong) the perihelion was passed, and nothing more to be hoped for from observations, i seized upon a pleasant day and went to the cape for an excursion. we went to yarmouth, sandwich, and plymouth, enjoying the novelty of the new car-route. it really seemed like railway travelling on our own island, so much sand and so flat a country. "the little towns, too, seemed quaint and odd, and the old gray cottages looked as if they belonged to the last century, and were waked from a long nap by the railway whistle. "i thought sandwich a beautiful, and plymouth an interesting, town. i would fain have gone off into some poetical quotation, such as 'the breaking waves dashed high' or 'the pilgrim fathers, where are they?' but k., who had been there before, desired me not to be absurd, but to step quietly on to the half-buried rock and quietly off. younger sisters know a deal, so i did as i was bidden to do, and it was just as well not to make myself hoarse without an appreciative audience. "i liked the picture by sargent in pilgrim hall, but seeing plymouth on a mild, sunny day, with everything looking bright and pleasant, it was difficult to conceive of the landing of the pilgrims as an event, or that the settling of such a charming spot required any heroism. "the picture, of course, represents the dreariness of winter, and my feelings were moved by the chilled appearance of the little children, and the pathetic countenance of little peregrine white, who, considering that he was born in the harbor, is wonderfully grown up before they are welcomed by samoset. according to history little peregrine was born about december 6 and samoset met them about march 16; so he was three months old, but he is plainly a forward child, for he looks up very knowingly. such a child had immortality thrust upon him from his birth. it must have had a deadening influence upon him to know that he was a marked man whether he did anything worthy of mark or not. he does not seem to have made any figure after his entrance into the world, though he must have created a great sensation when he came. "october 17. i have just gone over my comet computations again, and it is humiliating to perceive how very little more i know than i did seven years ago when i first did this kind of work. to be sure, i have only once in the time computed a parabolic orbit; but it seems to me that i know no more in general. i think i am a little better thinker, that i take things less upon trust, but at the same time i trust myself much less. the world of learning is so broad, and the human soul is so limited in power! we reach forth and strain every nerve, but we seize only a bit of the curtain that hides the infinite from us. "will it really unroll to us at some future time? aside from the gratification of the affections in another world, that of the intellect must be great if it is enlarged and its desires are the same. "nov. 24, 1854. yesterday james freeman clarke, the biographer of margaret fuller, came into the atheneum. it was plain that he came to see me and not the institution.... he rushed into talk at once, mostly on people, and asked me about my astronomical labors. as it was a kind of flattery, i repaid it in kind by asking him about margaret fuller. he said she did not strike any one as a person of intellect or as a student, for all her faculties were kept so much abreast that none had prominence. i wanted to ask if she was a lovable person, but i did not think he would be an unbiassed judge, she was so much attached to him. "dec. 5, 1854. the love of one's own sex is precious, for it is neither provoked by vanity nor retained by flattery; it is genuine and sincere. i am grateful that i have had much of this in my life. "the comet looked in upon us on the 29th. it made a twilight call, looking sunny and bright, as if it had just warmed itself in the equinoctial rays. a boy on the street called my attention to it, but i found on hurrying home that father had already seen it, and had ranged it behind buildings so as to get a rough position. "it was piping cold, but we went to work in good earnest that night, and the next night on which we could see it, which was not until april. "i was dreadfully busy, and a host of little annoyances crowded upon me. i had a good star near it in the field of my comet-seeker, but _what_ star? "on that rested everything, and i could not be sure even from the catalogue, for the comet and the star were so much in the twilight that i could get no good neighboring stars. we called it arietes, or 707. "then came a waxing moon, and we waxed weary in trying to trace the fainter and fainter comet in the mists of twilight and the glare of moonlight. "next i broke a screw of my instrument, and found that no screw of that description could be bought in the town. "i started off to find a man who could make one, and engaged him to do so the next day. the next day was fast day; all the world fasted, at least from labor. "however, the screw was made, and it fitted nicely. the clouds cleared, and we were likely to have a good night. i put up my instrument, but scarcely had the screw-driver touched the new screw than out it flew from its socket, rolled along the floor of the 'walk,' dropped quietly through a crack into the gutter of the house-roof. i heard it click, and felt very much like using language unbecoming to a woman's mouth. "i put my eye down to the crack, but could not see it. there was but one thing to be done,--the floor-boards must come up. i got a hatchet, but could do nothing. i called father; he brought a crowbar and pried up the board, then crawled under it and found the screw. i took good care not to lose it a second time. "the instrument was fairly mounted when the clouds mounted to keep it company, and the comet and i again parted. "in all observations, the blowing out of a light by a gust of wind is a very common and very annoying accident; but i once met with a much worse one, for i dropped a chronometer, and it rolled out of its box on to the ground. we picked it up in a great panic, but it had not even altered its rate, as we found by later observations. "the glaring eyes of the cat, who nightly visited me, were at one time very annoying, and a man who climbed up a fence and spoke to me, in the stillness of the small hours, fairly shook not only my equanimity, but the pencil which i held in my hand. he was quite innocent of any intention to do me harm, but he gave me a great fright. "the spiders and bugs which swarm in my observing-houses i have rather an attachment for, but they must not crawl over my recording-paper. rats are my abhorrence, and i learned with pleasure that some poison had been placed under the transit-house. "one gets attached (if the term may be used) to certain midnight apparitions. the aurora borealis is always a pleasant companion; a meteor seems to come like a messenger from departed spirits; and the blossoming of trees in the moonlight becomes a sight looked for with pleasure. "aside from the study of astronomy, there is the same enjoyment in a night upon the housetop, with the stars, as in the midst of other grand scenery; there is the same subdued quiet and grateful seriousness; a calm to the troubled spirit, and a hope to the desponding. "even astronomers who are as well cared for as are those of cambridge have their annoyances, and even men as skilled as they are make blunders. "i have known one of the bonds,[footnote: of the harvard college observatory.] with great effort, turn that huge telescope down to the horizon to make an observation upon a blazing comet seen there, and when he had found it in his glass, find also that it was not a comet, but the nebula of andromeda, a cluster of stars on which he had spent much time, and which he had made a special object of study. "dec. 26, 1854. they were wonderful men, the early astronomers. that was a great conception, which now seems to us so simple, that the earth turns upon its axis, and a still greater one that it revolves about the sun (to show this last was worth a man's lifetime, and it really almost cost the life of galileo). somehow we are ready to think that they had a wider field than we for speculation, that truth being all unknown it was easier to take the first step in its paths. but is the region of truth limited? is it not infinite?... we know a few things which were once hidden, and being known they seem easy; but there are the flashings of the northern lights--'across the lift they start and shift;' there is the conical zodiacal beam seen so beautifully in the early evenings of spring and the early mornings of autumn; there are the startling comets, whose use is all unknown; there are the brightening and flickering variable stars, whose cause is all unknown; and the meteoric showers--and for all of these the reasons are as clear as for the succession of day and night; they lie just beyond the daily mist of our minds, but our eyes have not yet pierced through it." chapter iii 1855-1857 extracts from diary--rachel--emerson--a hard winter "jan. 1, 1855. i put some wires into my little transit this morning. i dreaded it so much, when i found yesterday that it must be done, that it disturbed my sleep. it was much easier than i expected. i took out the little collimating screws first, then i drew out the tube, and in that i found a brass plate screwed on the diaphragm which contained the lines. i was at first a little puzzled to know which screws held this diaphragm in its place, and, as i was very anxious not to unscrew the wrong ones, i took time to consider and found i need turn only two. then out slipped the little plate with its three wires where five should have been, two having been broken. as i did not know how to manage a spider's web, i took the hairs from my own head, taking care to pick out white ones because i have no black ones to spare. i put in the two, after first stretching them over pasteboard, by sticking them with sealing-wax dissolved in alcohol into the little grooved lines which i found. when i had, with great labor, adjusted these, as i thought, firmly, i perceived that some of the wax was on the hairs and would make them yet coarser, and they were already too coarse; so i washed my little camel's-hair brush which i had been using, and began to wash them with clear alcohol. almost at once i washed out another wire and soon another and another. i went to work patiently and put in the five perpendicular ones besides the horizontal one, which, like the others, had frizzled up and appeared to melt away. with another hour's labor i got in the five, when a rude motion raised them all again and i began over. just at one o'clock i had got them all in again. i attempted then to put the diaphragm back into its place. the sealing-wax was not dry, and with a little jar i sent the wires all agog. this time they did not come out of the little grooved lines into which they were put, and i hastened to take out the brass plate and set them in parallel lines. i gave up then for the day, but, as they looked well and were certainly in firmly, i did not consider that i had made an entire failure. i thought it nice ladylike work to manage such slight threads and turn such delicate screws; but fine as are the hairs of one's head, i shall seek something finer, for i can see how clumsy they will appear when i get on the eyepiece and magnify their imperfections. they look parallel now to the eye, but with a magnifying power a very little crook will seem a billowy wave, and a faint star will hide itself in one of the yawning abysses. "january 15. finding the hairs which i had put into my instrument not only too coarse, but variable and disposed to curl themselves up at a change of weather, i wrote to george bond to ask him how i should procure spider lines. he replied that the web from cocoons should be used, and that i should find it difficult at this time of year to get at them. i remembered at once that i had seen two in the library room of the atheneum, which i had carefully refrained from disturbing. i found them perfect, and unrolled them.... fearing that i might not succeed in managing them, i procured some hairs from c.'s head. c. being not quite a year old, his hair is remarkably fine and sufficiently long.... i made the perpendicular wires of the spider's webs, breaking them and doing the work over again a great many times.... i at length got all in, crossing the five perpendicular ones with a horizontal one from c.'s spinning-wheel.... after twenty-four hours' exposure to the weather, i looked at them. the spider-webs had not changed, they were plainly used to a chill and made to endure changes of temperature; but c.'s hair, which had never felt a cold greater than that of the nursery, nor a change more decided than from his mother's arms to his father's, had knotted up into a decided curl!--n.b. c. may expect ringlets. "january 22. horace greeley, in an article in a recent number of the 'tribune,' says that the fund left by smithson is spent by the regents of that institution in publishing books which no publisher would undertake and which do no good to anybody. now in our little town of nantucket, with our little atheneum, these volumes are in constant demand.... "i do not suppose that such works as those issued by the smithsonian regents are appreciated by all who turn them over, but the ignorant learn that such things exist; they perceive that a higher cultivation than theirs is in the world, and they are stimulated to strive after greater excellence. so i steadily advocate, in purchasing books for the atheneum, the lifting of the people. 'let us buy, not such books as the people want, but books just above their wants, and they will reach up to take what is put out for them.' "sept. 10, 1855. to know what one ought to do is certainly the hardest thing in life. 'doing' is comparatively easy; but there are no laws for your individual case--yours is one of a myriad. "there are laws of right and wrong in general, but they do not seem to bear upon any particular case. "in chess-playing you can refer to rules of movement, for the chess-men are few, and the positions in which they may be placed, numerous as they are, have a limit. "but is there any limit to the different positions of human beings around you? is there any limit to the peculiarities of circumstances? "here a man, however much of a copyist he may be by nature, comes down to simple originality, unless he blindly follows the advice of some friend; for there is no precedent in anything exactly like his case; he must decide for himself, and must take the step alone; and fearfully, cautiously, and distrustingly must we all take many of our steps, for we see but a little way at best, and we can foresee nothing at all. "september 13. i read this morning an article in 'putnam's magazine,' on rachel. i have been much interested in this woman as a genius, though i am pained by the accounts of her career in point of morals, and i am wearied with the glitter of her jewelry. night puts on a jewelled robe which few admire, compared with the admiration for marketable jewelry. the new york 'tribune' descends to the rating of the value of those worn by her, and it is the prominent point, or rather it makes the multitude of prominent points, when she is spoken of. "the writer in 'putnam' does not go into these small matters, but he attempts a criticism on acting, to which i am not entirely a convert. he maintains that if an actor should really show a character in such light that we could not tell the impersonation from the reality, the stage would lose its interest. i do not think so. we should draw back, of course, from physical suffering; but yet we should be charmed to suppose anything real, which we had desired to see. if we felt that we really met cardinal wolsey or henry viii. in his days of glory, would it not be a lifelong memory to us, very different from the effect of the stage, and if for a few moments we really _felt_ that we had met them, would it not lift us into a new kind of being? "what would we not give to see julius caesar and the soothsayer, just as they stood in rome as shakspere represents them? why, we travel hundreds of miles to see the places noted for the doings of these old romans; and if we could be made to believe that we met one of the smaller men, even, of that day, our ecstasy would be unbounded. 'a tin pan so painted as to deceive is atrocious,' says this writer. of course, for we are not interested in a tin pan; but give us a portrait of shakspere or milton so that we shall feel that we have met them, and i see no atrocity in the matter. we honor the homes of these men, and we joy in the hope of seeing them. what would be beyond seeing them in life? "october 31. i saw rachel in 'phèdre' and in 'adrienne.' i had previously asked a friend if i, in my ignorance of acting, and in my inability to tell good from poor, should really perceive a marked difference between rachel and her aids. she thought i should. i did indeed! in 'phèdre,' which i first saw, she was not aided at all by her troupe; they were evidently ill at ease in the greek dress and in greek manners; while she had assimilated herself to the whole. it is founded on the play of euripides, and even to rachel the passion which she represents as phèdre must have been too strange to be natural. hippolytus refuses the love which phèdre offers after a long struggle with herself, and this gives cause for the violent bursts in which rachel shows her power. it was an outburst of passion of which i have no conception, and i felt as if i saw a new order of being; not a woman, but a personified passion. the vehemence and strength were wonderful. it was in parts very touching. there was as fine an opportunity for aricia to show some power as for phèdre, but the automaton who represented aricia had no power to show. oenon, whom i took to be the sister sarah, was something of an actress, but her part was so hateful that no one could applaud her. i felt in reading 'phèdre,' and in hearing it, that it was a play of high order, and that i learned some little philosophy from some of its sentiments; but for 'adrienne' i have a contempt. the play was written by scribe specially for rachel, and the french acting was better done by the other performers than the greek. i have always disliked to see death represented on the stage. rachel's representation was awful! i could not take my eyes from the scene, and i held my breath in horror; the death was so much to the life. it is said that she changes color. i do not know that she does, but it looked like a ghastly hue that came over her pale face. "i was displeased at the constant standing. neither as greeks nor as frenchmen did they sit at all; only when dying did rachel need a chair. they made love standing, they told long stories standing, they took snuff in that position, hat in hand, and rachel fainted upon the breast of some friend from the same fatiguing attitude. "the audience to hear 'adrienne' was very fine. the unitarian clergymen and the divinity students seemed to have turned out. "most of the two thousand listeners followed with the book, and when the last word was uttered on the french page, over turned the two thousand leaves, sounding like a shower of rain. the applause was never very great; it is said that rachel feels this as a boston peculiarity, but she ought also to feel the compliment of so large an audience in a city where foreigners are so few and the population so small compared to that of new york. "nov. 14, 1855. last night i heard emerson give a lecture. i pity the reporter who attempts to give it to the world. i began to listen with a determination to remember it in order, but it was without method, or order, or system. it was like a beam of light moving in the undulatory waves, meeting with occasional meteors in its path; it was exceedingly captivating. it surprised me that there was not only no commonplace thought, but there was no commonplace expression. if he quoted, he quoted from what we had not read; if he told an anecdote, it was one that had not reached us. at the outset he was very severe upon the science of the age. he said that inventors and discoverers helped themselves very much, but they did not help the rest of the world; that a great man was felt to the centre of the copernican system; that a botanist dried his plants, but the plants had their revenge and dried the botanist; that a naturalist bottled up reptiles, but in return the man was bottled up. "there was a pitiful truth in all this, but there are glorious exceptions. professor peirce is anything but a formula, though he deals in formulae. "the lecture turned at length upon beauty, and it was evident that personal beauty had made emerson its slave many a time, and i suppose every heart in the house admitted the truth of his words.... "it was evident that mr. emerson was not at ease, for he declared that good manners were more than beauty of face, and good expression better than good features. he mentioned that sir philip sydney was not handsome, though the boast of english society; and he spoke of the astonishing beauty of the duchess of hamilton, to see whom hundreds collected when she took a ride. i think in these cases there is something besides beauty; there was rank in that of the duchess, in the case of sydney there was no need of beauty at all. "dec. 16, 1855. all along this year i have felt that it was a hard year--the hardest of my life. and i have kept enumerating to myself my many trials; to-day it suddenly occurred to me that my blessings were much more numerous. if mother's illness was a sore affliction, her recovery is a great blessing; and even the illness itself has its bright side, for we have joyed in showing her how much we prize her continued life. if i have lost some friends by death, i have not lost all. if i have worked harder than i felt that i could bear, how much better is that than not to have as much work as i wanted to do. i have earned more money than in any preceding year; i have studied less, but have observed more, than i did last year. i have saved more money than ever before, hoping for europe in 1856." ... miss mitchell from her earliest childhood had had a great desire to travel in europe. she received a very small salary for her services in the atheneum, but small as it was she laid by a little every year. she dressed very simply and spent as little as possible on herself--which was also true of her later years. she took a little journey every year, and could always have little presents ready for the birthdays and christmas days, and for the necessary books which could not be found in the atheneum library, and which she felt that she ought to own herself,--all this on a salary which an ordinary school-girl in these days would think too meagre to supply her with dress alone. in this family the children were not ashamed to say, "i can't afford it," and were taught that nothing was cheap that they could not pay for--a lesson that has been valuable to them all their lives. ".... 1855. deacon greeley, of boston, urged my going to boston and giving some lectures to get money. i told him i could not think of it just now, as i wanted to go to europe. 'on what money?' said he. 'what i have earned,' i replied. 'bless me!' said he; 'am i talking to a capitalist? what a mistake i have made.'" during the time of the prosperity of the town, the winters were very sociable and lively; but when the inhabitants began to leave for more favorable opportunities for getting a livelihood, the change was felt very seriously, especially in the case of an exceptionally stormy winter. here is an extract showing how miss mitchell and her family lived during one of these winters: "jan. 22, 1857. hard winters are becoming the order of things. winter before last was hard, last winter was harder, and this surpasses all winters known before. "we have been frozen into our island now since the 6th. no one cared much about it for the first two or three days; the sleighing was good, and all the world was out trying their horses on main street--the racecourse of the world. day after day passed, and the thermometer sank to a lower point, and the winds rose to a higher, and sleighing became uncomfortable; and even the dullest man longs for the cheer of a newspaper. the 'nantucket inquirer' came out for awhile, but at length it had nothing to tell and nothing to inquire about, and so kept its peace. "after about a week a vessel was seen off siasconset, and boarded by a pilot. her captain said he would go anywhere and take anybody, as all he wanted was a harbor. two men whose business would suffer if they remained at home took passage in her, and with the pilot, patterson, she left in good weather and was seen off chatham at night. it was hoped that patterson would return and bring at least a few newspapers, but no more is known of them. our postmaster thought he was not allowed to send the mails by such a conveyance. "yesterday we got up quite an excitement because a large steamship was seen near the haul-over. she set a flag for a pilot, and was boarded. it was found that she was out of course, twenty days from glasgow, bound to new york. what the european news is we do not yet know, but it is plain that we are nearer to europe than to hyannis. christians as we are, i am afraid we were all sorry that she did not come ashore. we women revelled in the idea of the rich silks she would probably throw upon the beach, and the men thought a good job would be made by steamboat companies and wreck agents. "last night the weather was so mild that a plan was made for cutting out the steamboat; all the irishmen in town were ordered to be on the harbor with axes, shovels, and saws at seven this morning. the poor fellows were exulting in the prospect of a job, but they are sadly balked, for this morning at seven a hard storm was raging--snow and a good north-west wind. what has become of the english steamer no one knows, but the wind blows off shore, so she will not come any nearer to us. "inside of the house we amuse ourselves in various ways. f.'s family and ours form a club meeting three times a week, and writing 'machine poetry' in great quantities. occasionally something very droll puts us in a roar of laughter. f., e., and k. are, i think, rather the smartest, though mr. m. has written rather the best of all. at the next meeting, each of us is to produce a sonnet on a subject which we draw by lot. i have written mine and tried to be droll. k. has written hers and is serious. "i am sadly tried by this state of things. i cannot hear from cambridge (the nautical almanac office), and am out of work; it is cloudy most of the time, and i cannot observe; and i had fixed upon just this time for taking a journey. my trunk has been half packed for a month. "january 23. foreseeing that the thermometer would show a very low point last night, we sat up until near midnight, when it stood one and one-half below zero. the stars shone brightly, and the wind blew freshly from west north-west. "this morning the wind is the same, and the mercury stood at six and one-half below zero at seven o'clock, and now at ten a.m. is not above zero. the coffin school dismissed its scholars. miss f. suffered much from the exposure on her way to school. "the 'inquirer' came out this morning, giving the news from europe brought by the steamer which lies off 'sconset. no coal has yet been carried to the steamer, the carts which started for 'sconset being obliged to return. "there are about seven hundred barrels of flour in town; it is admitted that fresh meat is getting scarce; the streets are almost impassable from the snow-drifts. "k. and i have hit upon a plan for killing time. we are learning poetry--she takes twenty lines of goldsmith's 'traveller,' and i twenty lines of the 'deserted village.' it will take us twenty days to learn the whole, and we hope to be stopped in our course by the opening of the harbor. considering that k. has a fiancé from whom she cannot hear a word, she carries herself very amicably towards mankind. she is making herself a pair of shoes, which look very well; i have made myself a morning-dress since we were closed in. "last night i took my first lesson in whist-playing. i learned in one evening to know the king, queen, and jack apart, and to understand what my partner meant when she winked at me. "the worst of this condition of things is that we shall bear the marks of it all our lives. we are now sixteen daily papers behind the rest of the world, and in those sixteen papers are items known to all the people in all the cities, which will never be known to us. how prices have fluctuated in that time we shall not know--what houses have burned down, what robberies have been committed. when the papers do come, each of us will rush for the latest dates; the news of two weeks ago is now history, and no one reads history, especially the history of one's own country. "i bought a copy of 'aurora leigh' just before the freezing up, and i have been careful, as it is the only copy on the island, to circulate it freely. it must have been a pleasant visitor in the four or five households which it has entered. we have had dr. kane's book and now have the 'japan expedition.' "the intellectual suffering will, i think, be all. i have no fear of scarcity of provisions or fuel. there are old houses enough to burn. fresh meat is rather scarce because the english steamer required so much victualling. we have a barrel of pork and a barrel of flour in the house, and father has chickens enough to keep us a good while. "there are said to be some families who are in a good deal of suffering, for whom the howard society is on the lookout. mother gives very freely to bridget, who has four children to support with only the labor of her hands. "the coffin school has been suspended one day on account of the heaviest storm, and the unitarian church has had but one service. no great damage has been done by the gales. my observing-seat came thundering down the roof one evening, about ten o'clock, but all the world understood its cry of 'stand from under,' and no one was hurt. several windows were blown in at midnight, and houses shook so that vases fell from the mantelpieces. "the last snow drifted so that the sleighing was difficult, and at present the storm is so smothering that few are out. a. has been out to school every day, and i have not failed to go out into the air once a day to take a short walk. "january 24. we left the mercury one below zero when we went to bed last night, and it was at zero when we rose this morning. but it rises rapidly, and now, at eleven a.m., it is as high as fifteen. the weather is still and beautiful; the english steamer is still safe at her moorings. "our little club met last night, each with a sonnet. i did the best i could with a very bad subject. k. and e. rather carried the honors away, but mr. j. m.'s was very taking. our 'crambo' playing was rather dull, all of us having exhausted ourselves on the sonnets. we seem to have settled ourselves quietly into a tone of resignation in regard to the weather; we know that we cannot 'get out,' any more than sterne's starling, and we know that it is best not to fret. "the subject which i have drawn for the next poem is 'sunrise,' about which i know very little. k. and i continue to learn twenty lines of poetry a day, and i do not find it unpleasant, though the 'deserted village' is rather monotonous. "we hear of no suffering in town for fuel or provisions, and i think we could stand a three months' siege without much inconvenience as far as the physicals are concerned. "january 26. the ice continues, and the cold. the weather is beautiful, and with the thermometer at fourteen i swept with the telescope an hour and a half last night, comfortably. the english steamer will get off to-morrow. it is said that they burned their cabin doors last night to keep their water hot. many people go out to see her; she lies off 'sconset, about half a mile from shore. we have sent letters by her which, i hope, may relieve anxiety. "k. bought a backgammon board to-day. clifford [the little nephew] came in and spent the morning. "january 29. we have had now two days of warm weather, but there is yet no hope of getting our steamboat off. day before yesterday we went to 'sconset to see the english steamer. she lay so near the shore that we could hear the orders given, and see the people on board. when we went down the bank the boats were just pushing from the shore, with bags of coal. they could not go directly to the ship, but rowed some distance along shore to the north, and then falling into the ice drifted with it back to the ship. when they reached her a rope was thrown to them, and they made fast and the coal was raised. we watched them through a glass, and saw a woman leaning over the side of the ship. the steamer left at five o'clock that day. "it was worth the trouble of a ride to 'sconset to see the masses of snow on the road. the road had been cleared for the coal-carts, and we drove through a narrow path, cut in deep snow-banks far above our heads, sometimes for the length of three or four sleighs. we could not, of course, turn out for other sleighs, and there was much waiting on this account. then, too, the road was much gullied, and we rocked in the sleigh as we would on shipboard, with the bounding over hillocks of snow and ice. "now, all is changed: the roads are slushy, and the water stands in deep pools all over the streets. there is a dense fog, very little wind, and that from the east. the thermometer above thirty-six. "[mails arrived february 3, and our steamboat left february 5.]" chapter iv 1857 southern tour in 1857 miss mitchell made a tour in the south, having under her charge the young daughter of a western banker. "march 2, 1857. i left meadville this morning at six o'clock, in a stage-coach for erie. i had, early in life, a love for staging, but it is fast dying out. nine hours over a rough road are enough to root out the most passionate love of that kind. "our stage was well filled, but in spite of the solid base we occasionally found ourselves bumping up against the roof or falling forward upon our opposite neighbors. "stage-coaches are, i believe, always the arena for political debate. to-day we were all on one side, all buchanan men, and yet all anti-slavery. it seemed reasonable, as they said, that the south should cease to push the slave question in regard to kansas, now that it has elected its president. "when i took the stage out to meadville on the 'mud-road,' it was filled with fremont men, and they seemed to me more able men, though they were no younger and no more cultivated. "march 5. i believe any one might travel from maine to georgia and be perfectly ignorant of the route, and yet be well taken care of, mainly from the good-nature in every one. "i found from nantucket to chicago more attention than i desired. i had a short seat in one of the cars, through the night. i did not think it large enough for two, and so coiled myself up and went to sleep. there were men standing all around. once one of them came along and said something about there being room for him on my seat. another man said, 'she's asleep, don't disturb her.' i was too selfish to offer the half of a short seat, and too tired to reason about the man's being, possibly, more tired than i. "i was invariably offered the seat near the window that i might lean against the side of the car, and one gentleman threw his shawl across my knees to keep me warm (i was suffering with heat at the time!). another, seeing me going to chicago alone, warned me to beware of the impositions of hack-drivers; telling me that i must pay two dollars if i did not make a bargain beforehand. i found it true, for i paid one dollar for going a few steps only. "one peculiarity in travelling from east to west is, that you lose the old men. in the cars in new england you see white-headed men, and i kept one in the train up to new york, and one of grayish-tinted hair as far as erie; but after cleveland, no man was over forty years old. "for hundreds of miles the prairie land stretches on the illinois central railroad between chicago and st. louis. it may be pleasant in summer, but it is a dreary waste in winter. the space is too broad and too uniform to have beauty. the girdle of trees would be pretty, doubtless, if seen near, but in the distance and in winter it is only a black border to a brown plain. "the state of illinois must be capitally adapted to railroads on account of this level, and but little danger can threaten a train from running off of the track, as it might run on the soil nearly as well as on the rails. "our engine was uncoupled, and had gone on for nearly half a mile without the cars before the conductor perceived it. "the time from chicago to st. louis is called fifteen hours and a quarter; we made it twenty-three. "if the prairie land is good farming-land, illinois is destined to be a great state. if its people will think less of the dollar and more of the refinements of social life and the culture of the mind, it may become the great state of the union yet. "march 12. planter's hotel, st. louis. we visited mercantile hall and the library. the lecture-room is very spacious and very pretty. no gallery hides the frescoed walls, and no painful economy has been made of the space on the floor. "13th. i begin to perceive the commerce of st. louis. we went upon the levee this morning, and for miles the edge was bordered with the pipes of steamboats, standing like a picket-fence. then we came to the wholesale streets, and saw the immense stores for dry-goods and crockery. "to-day i have heard of a scientific association called the 'scientific academy of st. louis,' which is about a year old, and which is about to publish a volume of transactions, containing an account of an artesian well, and of some inscriptions just sent home from nineveh, which mr. gust. seyffarth has deciphered. "mr. seyffarth must be a remarkable man; he has translated a great many inscriptions, and is said to surpass champollion. he has published a work on egyptian astronomy, but no copy is in this country. "dr. pope, who called on me, and with whom i was much pleased, told me of all these things. western men are so proud of their cities that they spare no pains to make a person from the eastern states understand the resources, and hopes, and plans of their part of the land. "rev. dr. eliot i have not seen. he is about to establish a university here, for which he has already $100,000, and the academic part is already in a state of activity. "rev. mr. staples tells me that dr. eliot puts his hands into the pockets of his parishioners, who are rich, up to the elbows. "altogether, st. louis is a growing place, and the west has a large hand and a strong grasp. "doctor seyffarth is a man of more than sixty years, gray-haired, healthy-looking, and pleasant in manners. he has spent long years of labor in deciphering the inscriptions found upon ancient pillars, egyptian and arabic, dating five thousand years before christ. i asked him if he found the observations continuous, and he said that he did not, but that they seem to be astrological pictures of the configuration of the planets, and to have been made at the birth of princes. "he has just been reading the slabs sent from nineveh by mr. marsh; their date is only about five hundred years b.c. "mr. seyffarth's published works amount to seventy, and he was surprised to find a whole set of them in the astor library in new york. "march 19. we came on board of the steamer 'magnolia,' this morning, in great spirits. we were a little late, and miss s. rushed on board as if she had only new orleans in view. i followed a little more slowly, and the brigadier-general came after, in a sober and dignified manner. "we were scarcely on board when the plank was pulled in, and a few minutes passed and we were afloat on the mississippi river. miss s. and myself were the only lady passengers; we had, therefore, the whole range of staterooms from which to choose. each could have a stateroom to herself, and we talked in admiration of the pleasant times we should have, watching the scenery from the stateroom windows, or from the saloon, reading, etc. "we started off finely. i, who had been used only to the rough waters of the atlantic coast, was surprised at the steady gliding of the boat. i saw nothing of the mingling of the waters of the missouri and the mississippi of which i had been told. perhaps i needed somebody to point out the difference. "the two banks of the river were at first much alike, but after a few hours the left bank became more hilly, and at intervals presented bluffs and rocks, rude and irregular in shape, which we imagined to be ruins of some old castle. "at intervals, too, we passed steamers going up to st. louis, all laden with passengers. we exulted in our majestic march over the waters. i thought it the very perfection of travelling, and wished that all my family and all my friends were on board. "i wondered at the stupidity of the rest of the world, and thought that they ought all to leave the marts of business, to step from the desk, the counting-room, and the workshop on board the 'magnolia,' and go down the length of the 'father of waters.' "and so they would, i suppose, but for sand-bars. here we are five hours out, and fast aground! we were just at dinner, the captain making himself agreeable, the dinner showing itself to be good, when a peculiar motion of the boat made the captain heave a sigh--he had been heaving the lead all the morning. 'ah,' he said, 'just what i feared; we've got to one of those bad places, and we are rubbing the bottom.' "i asked very innocently if we must wait for the tide, and was informed that there was no tide felt on this part of the river. miss s. turned a little pale, and showed a loss of appetite. i was a little bit moved, but kept it to myself and ate on. "as soon as dinner was over, we went out to look at the prospect of affairs. we were close into the land, and could be put on shore any minute; the captain had sent round a little boat to sound the waters, and the report brought back was of shallow water just ahead of us, but more on the right and left. "while we stood on deck a small boat passed, and a sailor very gleefully called out the soundings as he threw the lead, 'eight and a half-nine.' "but we are still high and dry now at two o'clock p.m. they are shaking the steamer, and making efforts to move her. they say if she gets over this, there is no worse place for her to meet. "i asked the captain of what the bottom is composed, and he says, 'of mud, rocks, snags, and everything.' "he is now moving very cautiously, and the boat has an unpleasant tremulous motion. "march 20. latitude about thirty-eight degrees. we are just where we stopped at noon yesterday--there is no change, and of course no event. one of our crew killed a 'possum yesterday, and another boat stopped near us this morning, and seems likely to lie as long as we do on the sand-bar. "we read shakspere this morning after breakfast, and then betook ourselves to the wheel-house to look at the scenery again. while there a little colored boy came to us bearing a waiter of oranges, and telling us that the captain sent them with his compliments. we ate them greedily, because we had nothing else to do. "21st. still the sand-bar. no hope of getting off. we heard the pilot hail a steamboat which was going up to st. louis, and tell them to send on a lighter, and i suppose we must wait for that.... it is my private opinion that this great boat will not get off at all, but will lie here until she petrifies.... "march 24. we left the 'magnolia' after four days and four hours upon the sand-bar near turkey island, upon seeing the 'woodruff' approach. we left in a little rowboat, and it seemed at first as if we could not overtake the steamer; but the captain saw us and slackened his speed. "miss s. and i clutched hands in a little terror as our small boat seemed likely to run under the great steamer, but our oarsmen knew their duty and we were safely put on board of the 'woodruff.' "march 25. we stopped at cairo at eight o'clock this morning. mr. s. went on shore and brought newspapers on board. the cairo paper i do not think of high order. i saw no mention in it of the detention of the 'magnolia'! "march 26. yesterday we count as a day of events. it began to look sunny on the banks, especially on the kentucky side, and miss s. and i saw cherry-blossoms. we remembered the eclipse, and mr. s. having brought with him a piece of broken glass from one of the windows of the 'magnolia,' i smoked it over a piece of candle which i had brought from room no. 22 of the planter's house at st. louis, and we prepared to see the eclipse. "i expected to see the moon on at five o'clock and twenty minutes, but as i had no time i could not tell when to look for it. "it was not on at that time by my watch, but in ten minutes after was so far on that i think my time cannot be much wrong. "it was a little cloudy, so that we saw the sun only 'all flecked with bars,' and caught sight of the phenomenon at intervals. "we were at a coal-landing at the time, and not far from madrid. the boat stopped so long to take in an immense pile of corn-bags that our passengers went on shore--such of them as could climb the slippery bank. "when we saw them coming back laden with peach-blossoms, and saw the little children dressing their hats with them, we were seized with a longing for them, and mr. s. offered to go and get us some; we begged to go too, but he objected. "we were really envious of his good luck when we saw him jump into a country wagon, drawn by oxen which trotted off like horses, and, waving his handkerchief to us, ride off in great glee. he came back with an armful of peach-tree branches. whose orchard he robbed at our instigation i cannot say. a little girl, the daughter of the captain, pulled some blossoms open, and showed us that the fruit germs were not dead, but would have become peaches if we had not coveted them. "the 25th was also our first night steam-boating. after passing cairo the river is considered safe for night travel, and the boat started on her way at 8.30 p.m. we had been out about half an hour when a lady who was playing cards threw down her cards and rushed with a shriek to her stateroom. i perceived then that there had been a peculiar motion to the boat and that it suddenly stopped. we found that one of the paddle-wheels was caught in a snag, but there was no harm done. it made us a little nervous, but we slept well enough after it. "when i look out upon the river, i wonder that boats are not continually snagged. little trees are sticking up on all sides, and sometimes we seem to be going over a meadow and pushing among rushes. "a yawl, which was sent out yesterday to sound, was snagged by a stump which was high out of water; probably they were carried on to it by a current. the little boat whirled round and round, and the men were plainly frightened, for they dropped their oars and clutched the sides of the boat. they got control, however, in a few minutes, and had the jeers of the men left on the steamer for their pains. "march 30. we stopped at natchez before breakfast this morning, and, having half an hour, we took a carriage and drove through the city. it was like driving through a succession of gardens: roses were hanging over the fences in the richest profusion, and the arbor-vitae was ornamenting every little nook, and adorning every cottage. "natchez stands on a high bluff, very romantic in appearance; jagged and rugged, as if volcanoes had been at work in a time long past, for tall trees grew in the ravines. "most of our lady passengers are, like ourselves, on a tour of pleasure; six of them go with us to the st. charles hotel. some are from keokuk, ia., and i think i like these the best. one young lady goes ashore to spend some time on a plantation, as a governess. she looks feeble, and we all pity her. "to-day we pass among plantations on both sides of the river. we begin to see the live-oak--a noble tree. the foliage is so thick and dark that i have learned to know it by its color. the magnolia trees, too, are becoming fragrant. "march 31. we are at length in new orleans, and up three flights at the st. charles, in a dark room. "the peculiarities of the city dawn upon me very slowly. i first noticed the showy dress of the children, then the turbaned heads of the black women in the streets, and next the bouquet-selling boys with their french phrases. "april 3. this morning we went to a slave market. it looked on first entrance like an intelligence office. men, women, and children were seated on long benches parallel with each other. all rose at our entrance, and continued standing while we were there. we were told by the traders to walk up and down the passage between them, and talk with them as we liked. as mr. s. passed the men, several lifted their hands and said, 'here's the boy that will suit you; i can do any kind of work.' some advertised themselves with a good deal of tact. one woman pulled at my shawl and asked me to buy her. i told her that i was not a housekeeper. 'not married?' she asked.--'no.'--'well, then, get married and buy me and my husband.' "there was a girl among them whiter than i, who roused my sympathies very much. i could not speak to her, for the past and the future were too plainly told in her face. i spoke to another, a bright-looking girl of twelve. 'where were you raised?'--'in kentucky.'--'and why are you to be sold?'--'the trader came to kentucky, bought me, and brought me here.' i thought what right had i to be homesick, when that poor girl had left all her kindred for life without her consent. "i could hold my tongue and look around without much outward show of disgust, but to talk pleasantly to the trader i could not consent. he told me that he had been brought up in the business, but he thought it a pity. "no buyers were present, so there was no examination that was painful to look upon. "the slaves were intelligent-looking, and very healthy and neat in appearance. those who belonged to one owner were dressed alike--some in striped pink and white dresses, others in plaid, all a little showy. the men were in thick trousers and coarse dark-blue jackets. "april 5. we have been this morning to a negro church. we found it a miserable-looking house, mostly unpainted and unplastered, but well filled with the swarthy faces. they were singing when we entered; we were pointed to a good seat. "there may have been fifty persons present, all well dressed; the women in the fanciful checkered headdresses so much favored by the negro race, the men in clean collars, nankin trousers, and dark coats. all showed that they were well kept and well fed. "the audience was increased by new comers frequently, and these, whatever the exercise might be, shook hands with those around them as they seated themselves, and joined immediately in the services. the singing was by the whole congregation, the minister lining out the hymns as in the early times in new england. "several persons carried on the exercises from the pulpit, and in the prayers and sermon the audience took an active part, responding in groans, 'oh, yes,' or 'amen,' sometimes performing a kind of chant to accompany the words.... a negro minister said in his prayer, 'o god, we are not for much talking.' i was delighted at the prospect of a short discourse, but i found his 'not much talking' exactly corresponded to 'a good deal' in my use of words. he talked for a full hour. "there was something pleasing in the earnestness of the preacher and the sympathetic feeling of the audience, but their peculiar condition was not alluded to, and probably was not felt. "the discourse was almost ludicrous at times, and at times was pathetic. i saved up a few specimens: "'o god, you have said that where one or two are gathered together in your name, there will you be; if anything stands between us that you can't come, put it aside.' "'god wants a kingdom upon earth with which he can coin-cide, and that kingdom are your heart.' "'god is near you when you are at the wash-tub or the ironing-table.' "'brethren, i thought last sabbath i wouldn't live to this; a man gets such a notion sometimes.' "april 9, alabama river. some lessons we of the north might learn from the south, and one is a greater regard for human life. i asked the captain of our boat if they had any accidents in these waters. he said, 'we don't kill people at the south, we gave that up some years ago; we leave it to the north, and the north seems to be capable of doing it.' "the reason for this is, that they are in no hurry. the southern character is opposed to haste. safety is of more worth than speed, and there is no hurry. "every one at the south introduces its 'peculiar institution' into conversation. "they talk as i expected southern people of intelligence to talk; they lament the evil, and say, 'it is upon us, what can we do? to give them freedom would be cruel.' "southerners fall back upon the bible at once; there is more of the old-fashioned religion at the south than at the north; that is, they are not intellectual religionists. they are shocked by the irreligion of massachusetts, and by theodore parker. they read the bible, and can quote it; they are ready with it as an argument at every turn. i am of course not used to the warfare, and so withdraw from the fight. "one argument which three persons have brought up to me is the superior condition of the blacks now, to what it would have been had their parents remained in africa, and they been children of the soil. i make no answer to this, for if this is an argument, it would be our duty to enslave the heathen, instead of attempting to enlighten them. "we hear some anecdotes which are amusing. a judge smith, of south carolina, moved to alabama, and became a prominent man there. he was sent to the senate. he was violently opposed by a young man who said that but for his gray hair he would challenge him. judge smith said, 'you are not the first coward who has taken shelter beneath my gray hairs.' "the same judge smith, when a proposition came before the senate to build a state penitentiary, said, 'wall in the city of mobile; you will have your penitentiary and its inmates.' "so far i have found it easier to travel without an escort south and west than at the north; that is, i have more care taken of me. every one is courteous, too, in speech. i know that they cannot love massachusetts, but they are careful not to wound my feelings. they acknowledge it to be the great state in education; they point to a pretty village and say, 'almost as neat as a new england village.' "savannah, april 15.... to-day we left town at ten o'clock for a drive in any direction that we liked. mr. f. and i went in a buggy, and miss s. cantered behind us on her horse. "the road that we took led to some rice plantations ten miles out of the city. our path was ornamented by the live-oaks, cedar trees, the dogwood, and occasionally the mistletoe, and enlivened sometimes by the whistle of the mocking-bird. down low by the wheels grew the wild azalea and the jessamine. above our heads the spanish moss hung from the trees in beautiful drapery. "by mistake we drove into the plantation grounds of mr. gibbons, a man of wealth, who is seldom on his lands, and where the avenues are therefore a little wild, and the roads a little rough. "we came afterwards upon a road leading under the most magnificent oaks that i ever saw. i felt as if i were under the arched roof of some ancient cathedral. "the trees were irregularly grouped and of immense size, throwing their hundreds of arms far upon the background of heaven, and bearing the drapery of the spanish moss fold upon fold, as if they sought to keep their raiment from touching the earth. i was perfectly delighted, and think it the finest picture i have yet seen. "retracing our steps, we sought the plantation of mr. potter--a very different one from that of mr. gibbons, as all was finish and neatness; a fine mansion well stored with books, and some fine oaks, some of which mr. potter had planted himself. "mr. potter walked through the fields with us, and, stopping among the negro huts, he said to a little boy, 'call the children and give us some singing.' the little boy ran off, shouting, 'come and sing for massa;' and in a few minutes the little darkies might be seen running through the fields and tumbling over the fences in their anxiety to get to us, to the number of eighteen. "they sat upon the ground around us and began their song. the boy who led sang 'early in the morning,' and the other seventeen brought in a chorus of 'let us think of jesus.' then the leader set up something about 'god almicha,' to which the others brought in another chorus. "they were a dirty and shabby looking set, but as usual fat, even to the little babies, whom the larger boys were tending. one little girl as she passed mr. potter carelessly put her hand in his and said, 'good morning, massa.' "mrs. g. tells me an anecdote which shows the southern sentiment on the one subject. the ladies of charleston were much pleased with miss murray, and got up for her what they called a murray testimonial, a collection of divers pretty things made by their own hands. the large box was ready to be sent to england, but alas for miss murray! while they were debating in what way it should be sent to ensure its reaching her without cost to herself, in an unwise moment she sent twenty-five dollars to 'bleeding kansas,' and the fit of good feeling towards her ebbed; the 'testimonial' remains unsent. "april 23, charleston. this place is somewhat like boston in its narrow streets, but unlike boston in being quiet; as is all the south. quiet and moderation seem to be the attributes of southern cities. you need not hurry to a boat for fear it will leave at the hour appointed; it never does. "we took a carriage and drove along the battery. the snuff of salt air did me good. "then we went on to a garden of roses, owned and cultivated by a colored woman. she has some twenty acres devoted to flowers and vegetables, and she owns twenty 'niggers.' the universal term for slaves is 'niggers.' 'nigger, bring that horse,' 'nigger, get out of the way,' will be said by the finest gentleman, and 'my niggers' is said by every one. "i do not believe that the slaves are badly treated; there may be cases of it, but i have seen them only sleek, fat, and lazy. "the old buildings of charleston please me exceedingly. the houses are built of brick, standing end to the street, three stories in height, with piazza above piazza at the side; with flower gardens around, and magnolias at the gates; the winding steps to the mansions festooned with roses. "i have just called on miss rutledge, who lives in the second oldest house in the city; herself a fine specimen of antiquity, in her double-ruffled cap and plaided black dress; she chatted away like a young person, using the good old english. "april 26. to-day mr. capers called on me. i was pleased with the account he gave me of his college life, and of a meeting held by his class thirty years after they graduated. some thirty of them assembled at the revere house in boston; they spread a table with viands from all sections of the country. mr. capers sent watermelons, and another gentleman from kentucky sent the wines of his state. "they sat late at table; they renewed the old friendships and talked over college scenes, and when it was near midnight some one proposed that each should give a sketch of his life, so they went through in alphabetical order. "adams was the first. he said, 'you all remember how i waited upon table in commons. you know that i afterwards went through college, but you do not know that to this man [and he pointed to a classmate] i was indebted for the money that paid for my college course.' "anderson was the second, and he told of his two wives: of the first, much; of the second, little. bowditch came next, and he said he would tell of anderson's second wife, who was a miss lockworth, of lexington, ky. "anderson, a widower, and his brother went to lexington, carrying with them a letter of introduction to the father of the young lady. "while the brother was making an elaborate toilet, anderson strolled out, and came, in his walk, upon a beautiful residence, and saw, within the enclosure, some inviting grounds. he stopped and spoke to the porter, and found it was mr. lockworth's. he told the porter that he had letters to mr. lockworth, and was intending to call upon him. the porter was very communicative, and told him a good deal. anderson asked if there were not a pretty daughter. the porter asked him to walk around. as he entered the gate he reached a dollar to the man, and, being much pleased, when he came out he reached the porter another dollar. "anderson went back to the hotel, told his brother about it, and they set out together to deliver the letter. the brother knew mr. lockworth, and as they met him in the parlor, he walked up, shook hands with him, and asked to present his brother, lars anderson. 'no introduction is necessary,' said mr. lockworth; and putting his hand into his pocket, drawing out the two dollars, he added, 'i am already in your debt just this sum!' the 'pretty daughter' was sitting upon the sofa. "mr. capers told me that their autobiographies drew smiles and tears alternately; they continued till one o'clock; then one of the class said, 'brothers, do you know that not a wineglass has yet been turned up, not a drop of wine drunk? and all were at once so impressed with the conviction that they had all been lifted above the needs of the flesh that they refused to drink, and one of the clergymen of the class kneeling in prayer, they all knelt at once, even to some idle spectators who were looking on. "april 28. nothing can exceed the hospitality shown to us. we have several invitations for each day, and calls without limit. "i had heard mrs. holbrook described as a wonder, and i found her a very pleasing woman, all ready to talk, and talking with a richness of expression which shows a full mind. mrs. holbrook was a rutledge, and it was amusing, after seeing her, to open miss bremer's 'homes of the new world,' and read her extravagant comments. miss bremer was certainly made happy at belmont. "april 29. to-day i have been to see miss pinckney. she is the last representative of her name, is over eighty, and still retains the animation of youth, though somewhat shaken in her physical strength by age. i found her sitting in an armchair, her feet resting upon a cushion, surrounded by some half-dozen callers. "she rose at once when i entered, and insisted upon my occupying her seat, while she took a less comfortable one. "the walls of the room were ornamented with portraits of major-general pinckney by stuart, stuart's washington, one by morris of general thomas pinckney, and a portrait of miss pinckney's mother. "miss pinckney is a very plain woman, but much beloved for her benevolence. "it is said that on looking over her diary which she keeps, recording the reasons for her many gifts to her friends and to her slaves, such entries as these will be found: "'$---to mary, because she is married.' "'$---to julia, because she has no husband.' "miss pinckney showed me among her centre-table ornaments a miniature of washington; one of her grandmother, of exceeding beauty; one of each of the pinckneys whose portraits are on the walls. "charleston is full of ante-revolution houses, and they please me. they were built when there was no hurry; they were built to last, and they have lasted, and will yet last for the children of their present possessors. "nothing can be happier in expression than the faces of the colored children. they have what must be the ease of the lower classes in a despotic country. the slaves have no care, no ambition; their place is a fixed one--they know it, and take all the good they can get. the children are fat, sleek, and, inheriting no nervous longings from their parents, are on a constant grin--at play with loud laughs and high leaps. "may 1. it does not follow because the slaves are sleek and fat and really happy--for happy i believe they are--that slavery is not an evil; and the great evil is, as i always supposed, in the effect upon the whites. the few southern gentlemen that i know interest me from their courtesy, agreeable manners, and ready speech. they also strike me as childlike and fussy. i catch myself feeling that i am the man and they are women; and i see this even in the captain of a steamer. then they all like to talk sentiment--their religion is a feeling. "may 2. the negroes are remarkable for their courtesy of manner. those who belong to good families seem to pride themselves upon their dress and style. "a lady walking in charleston is never jostled by black or white man. the white man steps out of her way, the black man does this and touches his hat. the black woman bows--she is distinguished by her neat dress, her clean plaid head-dress, and her upright carriage. it would be well for some of our young ladies to carry burdens on their heads, even to the risk of flattening the instep, if by that means they could get the straight back of a slave. "mrs. w., who takes us out to drive, comes with her black coachman and a little boy. the coachman wears white gloves, and looks like a gentleman. the little boy rings door-bells when we stop. "when it rained the other day, mrs. w. dropped the window of the carriage, and desired the two to put on their shawls, for fear they would take cold. they are plainly a great care to their owners, for they are like children and cannot take care of themselves; and yet in another way the masters are like children, from the constant waiting upon that they receive. one would think, where one class does all the thinking and the other all the working, that masters would be active thinkers and slaves ready workers; but neither result seems to happen--both are listless and inactive. "may 3. i asked miss pinckney to-day if she remembered george washington. she and mrs. poinsett spoke at once. "'oh, yes, we were children,' said mrs. poinsett; 'but my father would have him come to see us, and he took each of us in his arms and kissed us; and at another time we went to mt. vernon and made him a visit.' "never were more intelligent old ladies than mrs. poinsett and miss pinckney. the latter stepped around like a young girl, and brought a heavy book to show me the sketch of her sister, marie henrietta pinckney, who, in the nullification time of 1830, wrote a pamphlet in defence of the state. "miss pinckney's father was the originator of the celebrated maxim, 'millions for defence, but not one cent for tribute.' their house was the headquarters for the nullifiers, and they had serenades, she said, without number. "it was pleasant to hear the old ladies chatter away, and it was interesting to think of the distinguished men who had been under that roof, and of the cultivated and beautiful women who had adorned the mansion. "miss pinckney, when i left, followed me to the door, and put into my hands an elegant little volume of poems, called 'reliquiai.' "they seem to be simple effusions of some person who died early. "may 9. we left charleston, its old houses and its good people, on monday, and reached augusta the same day. "augusta is prettily laid out, but the place is of little interest; and for the hotel where we stayed, i can only give this advice to its inmates: 'don't examine a black spot upon your pillow-case; go to sleep at once, and keep asleep if you can.' "when we were on the road from augusta to atlanta, the conductor said, 'if you are going on to nashville, you will be on the road in the night; people don't love to go on that road in the night. i don't know why.' "when we came to the nashville road, i thought that i knew 'why.' the road runs around the base of a mountain, while directly beneath it, at a great depth, runs a river. a dash off the track on one side would be against the mountain, on the other side would be into the river, while the sharp turns seem to invite such a catastrophe. when we were somewhat wrought up to a nervous excitement, the cars would plunge into the darkness of a tunnel--darkness such as i almost felt. "it was a picturesque but weary ride, and we were tired and hungry when we reached nashville. "may 11. to-day we have been out for a two-hours' drive. it is warm, cloudy, and looks like a tempest; we are too tired for much effort. "mrs. fogg, of nashville, took us to call on the widow of president polk. we found her at home, though apparently just ready for a walk. she is still in mourning, and tells me that she has not travelled fifty miles from home in the last eight years. "she spoke to me of governor briggs (of massachusetts), an old friend; of professor hare; and said that among her cards, on her return from a journey some years ago, she found charles sumner's; and forgetting at the moment who he was, she asked the servant who he was. 'the abolitionist senator from massachusetts--i asked him in,' was the reply. "mrs. polk talks readily, is handsome, elegant in figure, and shows at once that she is well read. she told me that she reads all the newspaper reports of the progress of science. she lives simply, as any new england woman would, though her house is larger than most private residences. "mrs. fogg told me many anecdotes of dorothea dix. that lady was, at one time, travelling alone, and was obliged to stop at some little village tavern. as she lay half asleep upon the sofa, the driver of the stage in which she was to take passage came into the room, approached her, and held a light to her closed eyes. she did not dare to move nor utter a sound, but when he turned away she opened her eyes and watched him. he went to the mail-bags, opened them, took out the letters, hastily broke the seals, took out money enclosed, put it into his pocket, closed the bags, and again approached her with his lamp. she shut her eyes and pretended to sleep again; then at the proper time entered the stage and pursued her journey. at the end of the journey she reported his conduct to the proper authorities. "i was a little doubtful about the propriety of going to the mammoth cave without a gentleman escort, but if two ladies travel alone they must have the courage of men. so i called the landlord as soon as we arrived at the cave house, and asked if we could have mat, who i had been told was the best guide now that stephen is ill. the landlord promised mat to me for two days. after dinner we made our first attempt. "the ground descends for some two hundred feet towards the mouth of the cave; then you come to a low hill, and you descend through a small aperture not at all imposing, in front of which trickles a little stream. for some little while we needed no light, but soon the guide lighted and gave to each of us a little lamp. mat took the lead, i came next, miss s. followed, and an old slave brought up in the rear. "i confess that i shuddered as i came into the darkness. our lamps, of course, gave but feeble light; we barely saw at first where our feet must step. "i looked up, trying in vain to find the ceiling or the walls. all was darkness. in about an hour we saw more clearly. the chambers are, many of them, elliptical in shape; the ceiling is of mixed dark and white color, and looks much like the sky on a cloudy moonlight evening. "a friend of ours, who has been much in the cave, says, 'if the top were lifted off, and the whole were exposed to view, no woman would ever enter it again.' "we clambered over heaps of rocks, we descended ladders, wound through narrow passages, passed along chambers so low that we crouched for the whole length, entered upon lofty halls, ascended ladders, and crossed a bridge over a yawning abyss. "every nightmare scene that i had ever dreamed of seemed to be realized. i shuddered several times, and was obliged to reason with myself to assure me of safety. occasionally we sat down and rested upon some flat rock. "miss s., who has a great taste for costuming, wound her plaid shawl about her shoulders, turbaned her head with a green veil, swung her lamp upon a stick which she rested upon her shoulder, and then threw herself upon a rock in a most picturesque attitude. the guide took a lower seat, and his dirty tin cup, swung across his breast, looked like an ornament as the light struck it; his swarthy face was bright, and i wondered what our friends at home would give for a picture. "one of these elliptical halls has its ceiling immensely far off, and of the deepest black, until our feeble little lights strike upon innumerable points, when it shines forth like a dark starlight night. the stars are faint, but they look so exceedingly like the heavens that one easily forgets that it is not reality. "the guide asked us to be seated, while he went behind down a descent with the lights, to show us the creeping over of the shadows of the rocks, as if a dark cloud passed over the starlit vault. the black cloud crept on and on as the guide descended, until a fear came over us, and we cried out together to him to come back, not to leave us in total darkness. he begged that he might go still lower and show us entire darkness, but we would not permit it. "guin's dome. what the name means i can't say. the guide tells you to pause in your scrambling over loose stones and muddy soil,--which you are always willing to do,--and to put your head through a circular aperture, and to look up while he lights the bengal light; you obey, and look up upon columns of fluted, snowy whiteness; he tells you to look down, and you follow the same pillars down--up to heights which the light cannot climb, down to depths on which it cannot fall. "you shudder as you look up, and you shudder as you look down. indeed, the march of the cave is a series of shudders. geologists may enjoy it, a large party may be merry in it; but if the 'underground railroad' of the slaves is of that kind, i should rather remain a slave than undertake a runaway trip! "may 18. to-day we retraced our steps from nashville to chattanooga. it had been raining nearly all night, and we found, when not far from the latter place, that the streams were pouring down from the high lands upon the car-track, so that we came through rivers. when we dashed into the dark tunnel it was darker than ever from the darkness of the day, and it seemed to me that the darkness pressed upon me. i am sure i should keep my senses a very little while if i were confined in a dark place. "as we came out of the tunnel, the water from the hill above dashed upon the cars; and although it did not break the panes of glass, it forced its way through and sprinkled us. "the route, with all its terrors, is beautiful, and the trees are now much finer than they were ten days ago. "may 27. there is this great difference between niagara and other wonders of the world: that of it you get no idea from descriptions, or even from paintings. of the 'mammoth cave' you have a conception from what you are told; of the natural bridge you get a really truthful impression from a picture. but cave and bridge are in still life. niagara is all activity and change. no picture gives you the varying form of the water or the change of color; no description conveys to your mind the ceaseless roar. so, too, the ocean must be unrepresentable to those who have not looked upon it. "the natural bridge stands out bold and high, just as you expect to see it. you are agreeably disappointed, however, on finding that you can go under the arch and be completely in the coolness of its shade while you look up for two hundred feet to the rocky black and white ceiling above. "one of the prettiest peculiarities is the fringing above of the trees which hang over the edge, and looking out past the arch the wooded banks of the ravine are very pleasant. from above, one has the pain always attendant to me upon looking down into an abyss, but at the same time one obtains a better conception of the depth of the valley. it is well worth seeing, partly for itself, partly because it can be reached only by a ride among the hills of the blue ridge." chapter v 1857 first european tour--liverpool--the hawthornes--london--greenwich observatory--admiral smyth--dr. lee shortly after her return from the south, miss mitchell started again for a tour in europe with the same young girl. miss mitchell carried letters from eminent scientific people in this country to such persons as it would be desirable for her to know in europe; especially to astronomers and mathematicians. when miss mitchell went to europe she took her almanac work with her, and what time she was not sight-seeing she was continuing that work. her wisdom in this respect was very soon apparent. she had not been in england many weeks when a great financial crisis took place in the united states, and the father of her young charge succumbed to the general failure. the young lady was called home, but after considering the matter seriously miss mitchell decided to remain herself, putting the young lady into careful hands for the return passage from liverpool. miss mitchell enjoyed the society of the scientific people whom she met in england to her heart's content. she was very cordially received, and the astronomers not only opened their observatories to her, but welcomed her into their family life. on arriving at liverpool, miss mitchell delivered the letters to the astronomers living in or near that city, and visited their observatories. "aug. 3, 1857. i brought a letter from professor silliman to mr. john taylor, cotton merchant and astronomer; and to-day i have taken tea with him. he is an old man, nearly eighty i should think, but full of life, and talks by the hour on heathen mythology. he was the principal agent in the establishment of the liverpool observatory, but disclaims the honor, because it was established on so small a scale, compared with his own gigantic plan. mr. taylor has invented a little machine, for showing the approximate position of a comet, having the elements. "he has also made additions to the globes made by de morgan, so that they can be used for any year and show the correct rising and setting of the stars. "he struck me as being a man of taste, but of no great profundity. he has a painting which he believes to be by guido; it seemed to me too fresh in its coloring for the sixteenth century. "august 4, 3 p.m. i put down my pen, because old mr. taylor called, and while he was here rev. james martineau came. mr. martineau is one of the handsomest men i ever saw. he cannot be more than thirty, or if he is he has kept his dark hair remarkably. he has large, bluish-gray eyes, and is tall and elegant in manner. he says he is just packed to move to london. he gave me his london address and hoped he should see me there; but i doubt if he does, for i did not like to tell him my address unless he asked for it, for fear of seeming to be pushing. "august,... i have been to visit mr. lassell. he called yesterday and asked me to dine with him to-day. he has a charming place, about four miles out of liverpool; a pretty house and grounds. "mr. lassell has constructed two telescopes, both on the newtonian plan; one of ten, the other of twenty, feet in length. each has its separate building, and in the smaller building is a transit instrument. "mr. lassell must have been a most indefatigable worker as well as a most ingenious man; for, besides constructing his own instruments, he has found time to make discoveries. he is, besides, very genial and pleasant, and told me some good anecdotes connected with astronomical observations. "one story pleased me very much. our massachusetts astronomer, alvan clark, has long been a correspondent of mr. dawes, but has never seen him. wishing to have an idea of his person, and being a portrait painter, mr. clark sent to mr. dawes for his daguerreotype, and from that painted a likeness, which he has sent out to liverpool, and which is said to be excellent. "mr. lassell looks in at the side of his reflecting telescopes by means of a diagonal eye-piece; when the instrument is pointed at objects of high altitude he hangs a ladder upon the dome and mounts; the ladder moves around with the dome. mr. lassell works only for his own amusement, and has been to malta,--carrying his larger telescope with him,--for the sake of clearer skies. neither mr. lassell nor mr. hartnup [footnote: of the liverpool observatory.] makes regular observations. "the misses lassell, four in number, seem to be very accomplished. they take photographs of each other which are beautiful, make their own picture-frames, and work in the same workshop with their father. one of them told me that she made observations on my comet, supposing it to belong to mr. dawes, who was a friend of hers. "they keep an album of the autographs of their scientific visitors, and among them i saw those of professor young, of dartmouth, and of professor loomis. "august 4. i have just returned from a visit to the liverpool observatory, under the direction of mr. hartnup. it is situated on waterloo dock, and the pier of the observatory rests upon the sandstone of that region, the telescope is an equatorial; like many good instruments in our country, it is almost unused. "mr. hartnup's observatory is for nautical purposes. i found him a very gentlemanly person, and very willing to show me anything of interest about the observatory; but they make no regular series of astronomical observations, other than those required for the commerce of liverpool. "mr. hartnup has a clock which by the application of an electric current controls the action of other clocks, especially the town clock of liverpool--distant some miles. the current of electricity is not the motive power, but a corrector. "much attention is paid to meteorology. the pressure of the wind, the horizontal motion, and the course are recorded upon sheets of paper running upon cylinders and connected with the clock; the instrument which obeys the voice of the wind being outside. "aug. 5, 1857. i did not send my letter to mr. hawthorne until yesterday, supposing that he was not in the city; but yesterday when rev. james martineau called on me, he said that he had not yet left. mr. martineau said that it would be a great loss to liverpool when mr. hawthorne went away. "i sent my letter at once; from all that i had heard of mr. hawthorne's shyness, i thought it doubtful if he would call, and i was therefore very much pleased when his card was sent in this morning. mr. hawthorne was more chatty than i had expected, but not any more diffident. he remained about five minutes, during which time he took his hat from the table and put it back once a minute, brushing it each time. the engravings in the books are much like him. he is not handsome, but looks as the author of his books should look; a little strange and odd, as if not of this earth. he has large, bluish-gray eyes; his hair stands out on each side, so much so that one's thoughts naturally turn to combs and hair-brushes and toilet ceremonies as one looks at him." later, when miss mitchell was in paris, alone, on her way to rome, she sent to the hawthornes, who were also in paris, asking for the privilege of joining them, as they too were journeying in the same direction. she says in her diary: "mrs. hawthorne was feeble, and she told me that she objected, but that mr. hawthorne assured her that i was a person who would give no trouble; therefore she consented. we were about ten days on the journey to rome, and three months in rome; living, however, some streets asunder. i saw them nearly every day. like everybody else, i found mr. hawthorne very taciturn. his few words were, however, very telling. when i talked french, he told me it was capital: 'it came down like a sledge-hammer.' his little satirical remarks were such as these: it was march and i took a bunch of violets to rosa; notched white paper was wound around them, and mr. hawthorne said, 'they have on a cambric ruffle." "generally he sat by an open fire, with his feet thrust into the coals, and an open volume of thackeray upon his knees. he said that thackeray was the greatest living novelist. i sometimes suspected that the volume of thackeray was kept as a foil, that he might not be talked to. he shrank from society, but rode and walked." extract from a letter. rome, feb. 16, 1858. ... the hawthornes are invaluable to me, because the little ones come to my room every day and i go there when i like. mrs. hawthorne sometimes walks with us, mr. h. _never_. he has a horror of sight-seeing and of emotions in general, but i like him very much, and when i say i like _him_ it only means that i like _her_ a little more. julian, the boy, is in love with me. when i was last there mr. h. came home with me; as he put on his coat he turned to julian and said, "julian, i should think with your _tender interest_ in miss mitchell you wouldn't let me escort her home." "we arrived in rome in the evening. mrs. h. was somewhat of an invalid, and mr. hawthorne tried in vain to make the servant understand that she must have a fire in her room. he spoke no word of french, german, or italian, but he said emphatically, 'make a fire in mrs. hawthorne's room.' worn out with his efforts, he turned to me and said, 'do, miss mitchell, tell the servant what i want; your french is excellent! englishmen and frenchmen understand it equally well.' so i said in execrable french, 'make a fire,' and pointed to the grate; of course the gesture was understood. "mr. hawthorne was minutely and scrupulously honest; i should say that he was a rigid temperance man. once i heard mrs. hawthorne say to the clerk, 'send some brandy to mr. hawthorne at once.' we were six in the party. when i paid my bill i heard mr. hawthorne say to miss s., the teacher, who took all the business cares, 'don't let miss mitchell pay for one-sixth of my brandy.' "so if we ordered tea for five, and six partook of it, he called the waiter and said, 'six have partaken of the tea, although there was no tea added; to the amount.' "i told mr. hawthorne that a friend of mine, miss w., desired very much to see him, as she admired him very much. he said, 'don't let her see me, let her keep her little lamp burning.' "he was a sad man; i could never tell why. i never could get at anything of his religious views. "he was wonderfully blest in his family. mrs. hawthorne almost worshipped him. she was of a very serious and religious turn of mind. "i dined with them the day that una was sixteen years old. we drank her health in cold water. mr. hawthorne said, 'may you live happily, and be ready to go when you must.' "he joined in the family talk very pleasantly. one evening we made up a story. one said, 'a party was in rome;' another said, 'it was a pleasant day;' another said, 'they took a walk.' it came to hawthorne's turn, and he said, 'do put in an incident;' so rosa said, 'then a bear jumped from the top of st. peter's!' the story went no further. "i was with the family when they first went to st. peter's. hawthorne turned away saying, 'the st. peter's of my imagination was better.' "i think he could not have been well, he was so very inactive. if he walked out he took rosa, then a child of six, with him. he once came with her to my room, but he seemed tired from the ascent of the stairs. i was on the fifth floor. "i have been surprised to see that he made severe personal remarks in his journal, for in the three months that i knew him i never heard an unkind word; he was always courteous, gentle, and retiring. mrs. hawthorne said she took a wifely pride in his having no small vices. mr. hawthorne said to miss s., 'i have yet to find the first fault in mrs. hawthorne.' "one day mrs. hawthorne came to my room, held up an inkstand, and said, 'the new book will be begun to-night.' "this was 'the marble faun.' she said, 'mr. hawthorne writes after every one has gone to bed. i never see the manuscript until it is what he calls _clothed_'.... mrs. h. says he never knows when he is writing a story how the characters will turn out; he waits for _them_ to influence _him_. "i asked her if zenobia was intended for margaret fuller, and she said, 'no;' but mr. hawthorne admitted that margaret fuller seemed to be around him when he was writing it. "london, august. we went out for our first walk as soon as breakfast was over, and we walked on regent street for hours, looking in at the shop windows. the first view of the street was beautiful, for it was a misty morning, and we saw its length fade away as if it had no end. i like it that in our first walk we came upon a crowd standing around 'punch.' it is a ridiculous affair, but as it is as much a 'peculiar institution' as is southern slavery, i stopped and listened, and after we came into the house miss s. threw out some pence for them. we rested after the shop windows of regent street, took dinner, and went out again, this time to piccadilly. "the servility of the shopkeepers is really a little offensive. 'what shall i have the honor of showing you?' they say. "our chambermaid, at our lodgings, thanks us every time we speak to her. "i feel ashamed to reach a four-penny piece to a stout coachman who touches his hat and begs me to remember him. sometimes i am ready to say, 'how can i forget you, when you have hung around me so closely for half an hour?' "our waiter at the adelphi hotel, at liverpool, was a very respectable middle-aged man, with a white neck-cloth; he looked like a methodist parson. he waited upon us for five days with great gravity, and then another waiter told us that we could give our waiter what we pleased. we were charged £1 for 'attendance' in the bill, but i very innocently gave half as much more, as fee to the 'parson,' "august 14. to-day we took a brougham and drove around for hours. of course we didn't _see_ london, and if we stay a month we shall still know nothing of it, it is so immense. i keep thinking, as i go through the streets, of 'the rats and the mice, they made such a strife, he had to go to london,' etc., and especially 'the streets were so wide, and the lanes were so narrow;' for i never saw such narrow streets, even in boston. "we have begun to send out letters, but as it is 'out of season' i am afraid everybody will be at the watering-places. the greenwich observatory. "the observatory was founded by charles ii. the king that 'never said a foolish thing and never did a wise one' was yet sagacious enough to start an institution which has grown to be a thing of might, and this, too, of his own will, and not from the influence of courtiers. one of the hospital buildings of greenwich, then called the 'house of delights,' was the residence of henrietta maria, and the young prince probably played on the little hill now the site of the observatory. "but charles, though he started an observatory, did not know very well what was needed. the first building consisted of a large, octagonal room, with windows all around; it was considered sufficiently firm without any foundation, and sufficiently open to the heavens with no opening higher than windows. this room is now used as a place of deposit for instruments, and busts and portraits of eminent men, and also as the dancing-hall for the director's family. "under mr. airy's [footnote: the late sir george airy.] direction, the walls of the observing-room have become pages of its history. the transit instruments used by halley, bradley, and pond hang side by side; the zenith sector with which bradley discovered the 'aberration of light,' now moving rustily on its arc, is the ornament of another room; while the shelves of the computing-room are filled with volumes of unpublished observations of flamstead and others. "the observatory stands in greenwich park, the prettiest park i have yet seen; being a group of small hills. they point out oaks said to belong to elizabeth's time--noble oaks of any time. the observatory is one hundred and fifty feet above the sea level. the view from it is, of course, beautiful. on the north the river, the little thames, big with its fleet, is winding around the isle of dogs; on the left london, always overhung with a cloud of smoke, through which st. paul's and the houses of parliament peep. "mr. airy was exceedingly kind to me, and seemed to take great interest in showing me around. he appeared to be much gratified by my interest in the history of the observatory. he is naturally a despot, and his position increases this tendency. sitting in his chair, the zero-point of longitude for the world, he commands not only the little knot of observers and computers around him, but when he says to london, 'it is one o'clock,' london adopts that time, and her ships start for their voyages around the globe, and continue to count their time from that moment, wherever the english flag is borne. "it is singular what a quiet motive-power science is, the breath of a nation's progress. "mr. airy is not favorable to the multiplication of observatories. he predicted the failure of that at albany. he says that he would gladly destroy one-half of the meridian instruments of the world, by way of reform. i told him that my reform movement would be to bring together the astronomers who had no instruments and the instruments which had no astronomers. "mr. airy is exceedingly systematic. in leading me by narrow passages and up steep staircases, from one room to another of the irregular collection of rooms, he was continually cautioning me about my footsteps, and in one place he seemed to have a kind of formula: 'three steps at this place, ten at this, eleven at this, and three again.' so, in descending a ladder to the birthplace of the galvanic currents, he said, 'turn your back to the stairs, step down with the right foot, take hold with the right hand; reverse the operation in ascending; do not, on coming out, turn around at once, but step backwards one step first.' "near the throne of the astronomical autocrat is another proof of his system, in a case of portfolios. these contain the daily bills, letters, and papers, as they come in and are answered in order. when a portfolio is full, the papers are removed and are sewed together. each year's accumulation is bound, and the bound volumes of mr. airy's time nearly cover one side of his private room. "mr. airy replies to all kinds of letters, with two exceptions: those which ask for autographs, and those which request him to calculate nativities. both of these are very frequent. "in the drawing-room mr. airy is cheery; he loves to recite ballads and knows by heart a mass of verses, from 'a, apple pie,' to the 'lady of the lake.' "a lover of nature and a close observer of her ways, as well in the forest walk as in the vault of heaven, mr. airy has roamed among the beautiful scenery of the lake region until he is as good a mountain guide as can be found. he has strolled beside grassmere and ascended helvellyn. he knows the height of the mountain peaks, the shingles that lie on their sides, the flowers that grow in the valleys, the mines beneath the surface. "at one time the government survey planted what is called a 'man' on the top of one of the hills of the lake region. in a dry season they built up a stone monument, right upon the bed of a little pond. the country people missed the little pond, which had seemed to them an eye of nature reflecting heaven's blue light. they begged for the removal of the surveyor's pile, and mr. airy at once changed the station. "the established observatories of england do not step out of their beaten path to make discoveries--these come from the amateurs. in this respect they differ from america and germany. the amateurs of england do a great deal of work, they learn to know of what they and their instruments are capable, and it is done. "the library of greenwich observatory is large. the transactions of learned societies alone fill a small room; the whole impression of the thirty volumes of printed observations fills a wall of another room, and the unpublished papers of the early directors make of themselves a small manuscript library. "october 22, 1857. we have just returned from our fourth visit to greenwich, like the others twenty-four hours in length. we go again to-morrow to meet the sabines. "herr struve, the director of the pulkova observatory, is at greenwich, with his son karl. the old gentleman is a magnificent-looking fellow, very large and well proportioned; his great head is covered with white hair, his features are regular and handsome. when he is introduced to any one he thrusts both hands into the pockets of his pantaloons, and bows. i found that the son considered this position of the hands particularly _english_. however, the old gentleman did me the honor to shake hands with me, and when i told him that i brought a letter to him from a friend in america, he said, 'it is quite unnecessary, i know you without.' he speaks very good english. "herr struve's mission in england is to see if he can connect the trigonometrical surveys of the two countries. it is quite singular that he should visit england for this purpose, so soon after russia and england were at war. one of his sons was an army surgeon at the crimea. "five visitors remained all night at the observatory. i slept in a little round room and miss s. in another, at the top of a little jutting-out, curved building. mrs. airy says, 'mr. airy got permission of the board of visitors to fit up some of the rooms as lodging-rooms.' mr. airy said, 'my dear love, i did as i always do: i fitted them up first, and then i reported to the board that i had done it.' "october 23. another dinner-party at the observatory, consisting of the struves, general and mrs. sabine, professor and mrs. powell, mr. main, and ourselves; more guests coming to tea. "mrs. airy told me that she should arrange the order of the guests at table to please herself; that properly all of the married ladies should precede me, but that i was really to go first, with mr. airy. to effect this, however, she must explain it to mrs. sabine, the lady of highest rank. "so we went out, professor airy and myself, professor powell and mrs. sabine, general sabine and mrs. powell, mr. charles struve and miss s., mr. main, mrs. airy, and professor struve. "general sabine is a small man, gray haired and sharp featured, about seventy years old. he smiles very readily, and is chatty and sociable at once. he speaks with more quickness and ease than most of the englishmen i have met. mrs. sabine is very agreeable and not a bit of a blue-stocking. "the chat at table was general and very interesting. mr. airy says, 'the best of a good dinner is the amount of talk.' he talked of the great 'leviathan' which he and struve had just visited, then anecdotes were told by others, then they went on to comic poetry. mr. airy repeated 'the lost heir,' by hood. general sabine told droll anecdotes, and the point was often lost upon me, because of the local allusions. one of his anecdotes was this: 'archbishop whately did not like a professor named robert daly; he said the irish were a very contented people, they were satisfied with one _bob daily_.' i found that a 'bob' is a shilling. "when the dinner was over, the ladies left the room, and the gentlemen remained over their wine; but not for long, for mr. airy does not like it, and struve hates it. "then, before tea, others dropped in from the neighborhood, and the tea was served in the drawing-room, handed round informally. "august 15. westminster abbey interested me more than i had expected. we went into the chapels and admired the sculpture when the guide told us we ought, and stopped with interest sometimes over some tomb which he did not point out. "i stepped aside reverently when i found i was standing on the stone which covers the remains of dr. johnson. it is cracked across the middle. garrick lies by the side of johnson, and i thought at first that goldsmith lay near; but it is only a monument--the body is interred in temple churchyard. "you are continually misled in this way unless you refer at every minute to your guide-book, and to go through europe reading a guide-book which you can read at home seems to be a waste of time. on the stone beneath which addison lies is engraved the verse from tickell's ode: "'ne'er to these chambers where the mighty rest,' etc. "the base of newton's monument is of white marble, a solid mass large enough to support a coffin; upon that a sarcophagus rests. the remains are not enclosed within. as i stepped aside i found i had been standing upon a slab marked 'isaac newton,' beneath which the great man's remains lie. "on the side of the sarcophagus is a white marble slab, with figures in bas-relief. one of these imaginary beings appears to be weighing the planets on a steel-yard. they hang like peas! another has a pair of bellows and is blowing a fire. a third is tending a plant. "on this sarcophagus reclines a figure of newton, of full size. he leans his right arm upon four thick volumes, probably 'the principia,' and he points his left hand to a globe above his head on which the goddess urania sits; she leans upon another large book. "newton's head is very fine, and is probably a portrait. the left hand, which is raised, has lost two fingers. i thought at first that this had been the work of some 'undevout astronomer,' but when i came to 'read up' i found that at one time soldiers were quartered in the abbey, and probably one of them wanted a finger with which to crowd the tobacco into his pipe, and so broke off one. "august 17. to-day we have been to the far-famed british museum. i carried an 'open sesame' in the form of a letter given to me by professor henry, asking for me special attention from all societies with which the 'smithsonian' at washington is connected. "i gave the paper first to a police officer; a police officer is met at every turn in london. he handed it to another official, who said, 'you'd better go to the secretary.' "i walked in the direction towards which he pointed, a long way, until i found the secretary. he called another man, and asked him to show me whatever i wanted to see. "this man took me into another room, and consigned me to still another man--the fifth to whom i had been referred. no. 5 was an intelligent and polite person, and he began to talk about america at once. "i asked to see anything which had belonged to newton, and he told me they had one letter only,--from newton to leibnitz,--which he showed me. it was written in latin, with diagrams and formulae interspersed. the reply of leibnitz, copied by newton, was also in their collection, and an order from newton written while he was director of the mint. "no. 5 also showed me the illuminated manuscripts of the collection; they are kept locked in glass-topped cases, and a curtain protects them from the light. we saw also the oldest copy of the bible in the world. "the art of printing has brought incalculable blessings; but as i looked at a neat manuscript book by queen elizabeth, copied from another as a present to her father, i could not help thinking it was much better than worsted work! "a much-worn prayer-book was shown me, said to be the one used by lady jane grey when on the scaffold. nothing makes me more conscious that i am on foreign soil than the constant recurrence of associations connected with the executioner's block. we hung the quakers and we burned the witches, but we are careful not to remember the localities of our barbarisms; we show instead the plymouth rock or the washington elm. "among other things, we were shown the 'magna charta'--a few fragments of worn-out paper on which some words could be traced; now carefully preserved in a frame, beneath a glass. "thus far england has impressed me seriously; i cannot imagine how it has ever earned the name of 'merrie england.' "august 19. there are four great men whose haunts i mean to seek, and on whose footsteps i mean to stand: newton, shakspere, milton, and johnson. "to-day i told the driver to take me to st. martin's, where the guide-book says that newton lived. he put me down at the newton hotel, but i looked in vain to its top to see anything like an observatory. "i went into a wine-shop near, and asked a girl, who was pouring out a dram, in which house newton lived. she pointed, not to the hotel, but to a house next to a church, and said, 'that's it--don't you see a place on the top? that's where he used to study nights.' "it is a little, oblong-shaped observatory, built apparently of wood, and blackened by age. the house is a good-looking one--it seems to be of stone. the girl said the rooms were let for shops. "next i told the driver to take me to fleet street, to gough square, and to bolt court, where johnson lived and died. "bolt court lies on fleet street, and it is but few steps along a narrow passage to the house, which is now a hotel, where johnson died; but you must walk on farther through the narrow passage, a little fearful to a woman, to see the place where he wrote the dictionary. the house is so completely within a court, in which nothing but brick walls could be seen, that one wonders what the charm of london could be, to induce one to live in that place. but a great city always draws to itself the great minds, and there johnson probably found his enjoyment. "august 27. we took st. paul's church to-day. we took tickets for the vaults, the bell, the crypt, the whispering-gallery, the clock and all. we did not know what was before us. it was a little tiresome as far as the library and the room of nelson's trophies, but to my surprise, when the guide said, 'go that way for the clock,' he did not take the lead, but pointed up a staircase, and i found myself the pioneer in the narrowest and darkest staircase i ever ascended. it was really perfect darkness in some of the places, and we had to feel our way. we all took a long breath when a gleam of light came in at some narrow windows scattered along. at the top, in front of the clock works, stood a woman, who began at once to tell us the statistics of the pendulum, to which recital i did not choose to listen. she was not to go down with us, and, panting with fatigue and trembling with fright, we groped our way down again. "there was another long, but easy, ascent to the 'whispering-gallery,' which is a fine place from which to look down upon the interior of the church. the man in attendance looked like a respectable elderly gentleman. he told us to go to the opposite side of the gallery, and he would whisper to us. we went around, and, worn out with fatigue, dropped upon a bench. "the man began to whisper, putting his mouth to an opening in the wall; we heard noises, but could not tell what he said. "to my amazement, this very respectable-looking elderly gentleman, as we passed him in going out, whispered again, and as this time he put his mouth close to my ear, i understood! he said, 'if you will give anything for the whisper, it will be gratefully received.' there are notices all over the church forbidding fees, and i felt that the man was a beggar at best--more properly a pickpocket. "a figure of dr. johnson stands in one of the aisles of the church. it must be like him, for it is exceedingly ugly. "september 3. we have been three weeks in london 'out of season,' but with plenty of letters. at present we have as many acquaintances as we desire. last night we were at the opera, to-night we go out to dine, and to-morrow evening to a dance, the next day to admiral smyth's. "the opera fatigued me, as it always does. i tired my eyes and ears in the vain effort to appreciate it. mario was the great star of the evening, but i knew no difference. "one little circumstance showed me how an american, with the best intentions, may offend against good manners. american-like we had secured very good seats, were in good season, and as comfortable as the very narrow seats would permit us to be, before most of the audience arrived. the house filled, and we sat at our ease, feeling our importance, and quite unconscious that we were guilty of any impropriety. while the curtain was down, i heard a voice behind me say to the gentleman who was with us, 'is the lady on your left with you?'--'yes,' said mr. r.--'she wears a bonnet, which is not according to rule.'--'too late now,' said mr. r.--'it is my fault,' said the attendant; 'i ought not to have admitted her; i thought it was a hood.' "i was really in hopes that i should be ordered out, for i was exceedingly fatigued and should have been glad of some fresh air. on looking around, i saw that only the 'pit' wore bonnets. "september 6. we left london yesterday for aylesbury. it is two hours by railroad. like all railroads in england, it runs seemingly through a garden. in many cases flowers are cultivated by the roadside. "from aylesbury to stone, the residence of admiral smyth, it is two miles of stage-coach riding. stage-coaches are now very rare in england, and i was delighted with the chance for a ride. "we found the stage-coach crowded. the driver asked me if we were for st. john's lodge, and on my replying in the affirmative gave me a note which mrs. smyth had written to him, to ask for inside seats. the note had reached him too late, and he said we must go on the outside. he brought a ladder and we got up. for a minute i thought, 'what a height to fall from!' but the afternoon was so lovely that i soon forgot the danger and enjoyed the drive. there were six passengers on top. "aylesbury is a small town, and stone is a very small village. the driver stopped at what seemed to be a cultivated field, and told me that i was at my journey's end. on looking down i saw a wheelbarrow near the fence, and i remembered that mrs. smyth had said that one would be waiting for our luggage, and i soon saw mrs. smyth and her daughter coming towards us. it was a walk of about an eighth of a mile to the 'lodge'--a pleasant cottage surrounded by a beautiful garden. "admiral smyth's family go to a little church seven hundred years old, standing in the midst of tombstones and surrounded by thatched cottages. english scenery seems now (september) much like our southern scenery in april--rich and lovely, but wanting mountains and water. an english village could never be mistaken for an american one: the outline against the sky differs; a thatched cottage makes a very wavy line on the blue above. "we find enough in st. john's lodge, in the admiral's library, and in the society of the cultivated members of his family to interest us for a long time. "the admiral himself is upwards of sixty years of age, noble-looking, loving a good joke, an antiquarian, and a good astronomer. i picked up many an anecdote from him, and many curious bits of learning. "he tells a good story, illustrative of his enthusiasm when looking at a crater in the moon. he says the night was remarkably fine, and he applied higher and higher powers to his glass until he seemed to look down into the abyss, and imagining himself standing on its verge he felt himself falling in, and drew back with a shudder which lasted even after the illusion was over. "in speaking of stratford-upon-avon, the admiral told me that the lucy family, one of whose ancestors drove shakspere from his grounds, and who is caricatured in justice shallow, still resides on the same spot as in shakspere's time. he says no family ever retained their characteristics more decidedly. "some years ago one of this family was invited to a shakspere dinner. he resented the well-meant invitation, saying they must surely have forgotten how that _person_ treated his ancestor! "the amateur astronomers of england are numerous, but they are not like those of america. "in america a poor schoolmaster, who has some bright boys who ask questions, buys a glass and becomes a star-gazer, without time and almost without instruments; or a watchmaker must know the time, and therefore watches the stars as time-keepers. in almost all cases they are hard-working men. "in england it is quite otherwise. a wealthy gentleman buys a telescope as he would buy a library, as an ornament to his house. "admiral smyth says that no family is quite civilized unless it possesses a copy of some encyclopaedia and a telescope. the english gentleman uses both for amusement. if he is a man of philosophical mind he soon becomes an astronomer, or if a benevolent man he perceives that some friend in more limited circumstances might use it well, and he offers the telescope to him, or if an ostentatious man he hires some young astronomer of talent, who comes to his observatory and makes a name for him. then the queen confers the honor of knighthood, not upon the young man, but upon the owner of the telescope. sir james south was knighted for this reason. "we have been visiting hartwell house, an old baronial residence, now the property of dr. lee, a whimsical old man. "this house was for years the residence of louis xviii., and his queen died here. the drawing-room is still kept as in those days; the blue damask on the walls has been changed by time to a brown. the rooms are spacious and lofty, the chimney-pieces of richly carved marble. the ceiling of one room has fine bas-relief allegorical figures. "books of antiquarian value are all around--one whole floor is covered with them. they are almost never opened. in some of the rooms paintings are on the walls above the doors. "dr. lee's modern additions are mostly paintings of himself and a former wife, and are in very bad taste. he has, however, two busts of mrs. somerville, from which i received the impression that she is handsome, but mrs. smyth tells me she is not so; certainly she is sculpturesque. "the royal family, on their retreat from hartwell house, left their prayer-book, and it still remains on its stand. the room of the ladies of the bedchamber is papered, and the figure of a pheasant is the prevailing characteristic of the paper. the room is called 'the pheasant room.' one of the birds has been carefully cut out, and, it is said, was carried away as a memento by one of the damsels. "dr. lee is second cousin to sir george lee, who died childless. he inherits the estate, but not the title. the estate has belonged to the lees for four hundred years. as the doctor was a lee only through his mother, he was obliged to take her name on his accession to the property. he applied to parliament to be permitted to assume the title, and, being refused, from a strong tory he became a liberal, and delights in currying favor with the lowest classes; he has twice married below his rank. being remotely connected with the hampdens, he claims john hampden as one of his family, and keeps a portrait of him in a conspicuous place. "a summer-house on the grounds was erected by lady elizabeth lee, and some verses inscribed on its walls, written by her, show that the lees have not always been fools. "but dr. lee has his way of doing good. being fond of astronomy, he has bought an eight and a half feet equatorial telescope, and with a wisdom which one could scarcely expect, he employed admiral smyth to construct an observatory. he has also a fine transit instrument, and the admiral, being his near neighbor, has the privilege of using the observatory as his own. in the absence of the lees he has a private key, with which he admits himself and mrs. smyth. they make the observations (mrs. smyth is a very clever astronomer), sleep in a room called 'the admiral's room,' find breakfast prepared for them in the morning, and return to their own house when they choose. "i saw in the observatory a timepiece with a double second-hand; one of these could be stopped by a touch, and would, in that way, show an observer the instant when he thought a phenomenon, as an occultation for instance, had occurred, and yet permit him to go on with his count of the seconds, and, if necessary, correct his first impression. "admiral smyth is a hard worker, but i suspect that many of the amateur astronomers of england are dr. lees--rich men who, as a hobby, ride astronomy and employ a good astronomer. dr. lee gives the use of a good instrument to the curate; another to mr. payson, of cambridge, who has lately found a little planet. "i saw at admiral smyth's some excellent photographs of the moon, but in england they have not yet photographed the stars." chapter vi 1857 first european tour continued--cambridge university--ambleside--miss southey---the herschels--a london rout--edinboro' and glasgow observatories--"reflections and mutterings" "if any one wishes to know the customs of centuries ago in england, let him go to cambridge. "sitting at the window of the hotel, he will see the scholars, the fellows, the masters of arts, and the masters of colleges passing along the streets in their different gowns. very unbecoming gowns they are, in all cases; and much as the wearers must be accustomed to them, they seem to step awkwardly, and to have an ungraceful feminine touch in their motions. "everything that you see speaks of the olden time. even the images above the arched entrance to the courts around which the buildings stand are crumbling slowly, and the faces have an unearthly expression. "if the visitor is fortunate enough to have an introduction to one of the college professors, he will be taken around the buildings, to the libraries, the 'combination' room to which the fellows retire to chat over their wine, and perhaps even to the kitchen. "our first knowledge of cambridge was the entrance to trinity college and the master's lodge. "we arrived in cambridge just about at lunch time--one o'clock. "mrs. airy said to me, 'although we are invited to be guests of dr. whewell, he is quite too mighty a man to come to meet us." her sons, however, met us, and we walked with them to dr. whewell's. "the master's lodge, where dr. whewell lives, is one of the buildings composing the great pile of trinity college. one of the rooms in the lodge still remains nearly as in the time of henry viii. it is immense in size, and has two oriel windows hung with red velvet. in this room the queen holds her court when she is in cambridge; for the lodge then becomes a palace, and the 'master' retires to some other apartments, and comes to dinner only when asked. "it is said that the present master does not much like to submit to this position. "in this great room hang full-length portraits of henry and elizabeth. on another wall is a portrait of newton, and on a third the sweet face of a young girl, dr. whewell's niece, of whom i heard him speak as 'kate.' "dr. whewell received us in this room, standing on a rug before an open fireplace; a wood fire was burning cheerily. mrs. airy's daughter, a young girl, was with us. "dr. whewell shook hands with us, and we stood. i was very tired, but we continued to stand. in an american gentleman's house i should have asked if i might sit, and should have dropped upon a chair; here, of course, i continued to stand. after, perhaps, fifteen minutes, dr. whewell said, 'will you sit?' and the four of us dropped upon chairs as if shot! "the master is a man to be noted, even physically. he is much above ordinary size, and, though now gray-haired, would be extraordinarily handsome if it were not for an expression of ill-temper about the mouth. "an englishmen is proud; a cambridge man is the proudest of englishmen; and dr. whewell, the proudest of cambridge men. "in the opinion of a cambridge man, to be master of trinity is to be master of the world! "at lunch, to which we stayed, dr. whewell talked about american writers, and was very severe upon them; some of them were friends of mine, and it was not pleasant. but i was especially hurt by a remark which he made afterwards. americans are noted in england for their use of slang. the english suppose that the language of sam slick or of nasby is the language used in cultivated society. they do not seem to understand it, and i have no doubt to-day that lowell's comic poems are taken seriously. so at this table, dr. whewell, wishing to say that we would do something in the way of sight-seeing very thoroughly, turning to me, said, 'we'll go the whole hog, miss mitchell, as you say in america.' "i turned to the young american girl who sat next to me, and said, 'miss s., did you ever hear that expression except on the street?' 'never,' she replied. "afterwards he said to me, 'you in america think you know something about the english language, and you get out your webster's dictionary, and your worcester's dictionary, but we here in cambridge think we know rather more about english than you do.' "after lunch we went to the observatory. the cambridge observatory has the usual number of meridian instruments, but it has besides a good equatorial telescope of twenty feet in length, mounted in the english style; for mr. airy was in cambridge at the time of its establishment. in this pretty observatory, overlooking the peaceful plains, with some small hills in the distance, mr. and mrs. airy passed the first year of their married life. "professor challis, the director, is exceedingly short, thick-headed (in appearance), and, like many of the english, thick-tongued. while i was looking at the instruments, mrs. airy came into the equatorial house, bringing mr. adams, the rival of leverrier, [footnote: see chapter vii.]--another short man, but bright-looking, with dark hair and eyes, and again the thick voice, this time with a nasal twang. he is a fellow of pembroke college, and master of arts. if mr. adams had become a fellow of his own college, st. john, he must have gone into holy orders, as it is called; this he was not willing to do; he accepted a fellowship from pembroke. "mr. adams is a merry little man, loves games with children, and is a favorite with young ladies. "at 6.30 we went again to the lodge to dine. we were a little late, and the servant was in a great hurry to announce us; but i made him wait until my gloves were on, though not buttoned. he announced us with a loud voice, and dr. whewell came forward to receive us. being announced in this way, the other guests do not wait for an introduction. there was a group of guests in the drawing-room, and those nearest me spoke to me at once. "dinner was announced immediately, and dr. whewell escorted me downstairs, across an immense hall, to the dining-room, outside of which stood the waiters, six in number, arranged in a straight line, in livery, of course. one of them had a scarlet vest, short clothes, and drab coat. "as i sat next to the master, i had a good deal of talk with him. he was very severe upon americans; he said that emerson did not write good english, and copied carlyle! i thought his severity reached really to discourtesy, and i think he perceived it when he asked me if i knew emerson personally, and i replied that i did, and that i valued my acquaintance with him highly. "i got a little chance to retort, by telling him that we had outgrown mrs. hemans in america, and that we now read mrs. browning more. he laughed at it, and said that mrs. browning's poetry was so coarse that he could not tolerate it, and he was amused to hear that any people had got above mrs. hemans; and he asked me if we had outgrown homer! to which i replied that they were not similar cases. "altogether, there was a tone of satire in dr. whewell's remarks which i did not think amiable. "there were, as there are very commonly in english society, some dresses too low for my taste; and the wine-drinking was universal, so that i had to make a special point of getting a glass of water, and was afraid i might drink all there was on the table! "before the dessert came on, saucers were placed before each guest, and a little rose-water dipped into them from a silver basin; then each guest washed his face thoroughly, dipping his napkin into the saucer. professor willis, who sat next to me, told me that this was a custom peculiar to cambridge, and dating from its earliest times. "the finger bowls came on afterwards, as usual. "it is customary for the lady of the house or the 'first lady' to turn to her nearest neighbor at the close of dinner and say, 'shall we retire to the drawing-room?' now, there was no lady of the house, and i was in the position of first lady. they might have sat there for a thousand years before i should have thought of it. i drew on my gloves when the other ladies drew on theirs, and then we waited. mrs. airy saw the dilemma, made the little speech, and the gentlemen escorted us to the door, and then returned to their wine. "we went back to the drawing-room and had coffee; after coffee new guests began to come, and we went into the magnificent room with the oriel windows. "professor sedgwick came early--an old man of seventy-four, already a little shattered and subject to giddiness. he is said to be very fond of young ladies even now, and when younger made some heartaches; for he could not give up his fellowship and leave cambridge for a wife; which, to me, is very unmanly. he is considered the greatest geologist in england, and of course they would say 'in the world,' and is much loved by all who know him. he came to cambridge a young man, and the elms which he saw planted are now sturdy trees. it is pleasant to hear him talk of cambridge and its growth; he points to the stately trees and says, 'those trees don't look as old as i, and they are not.' "i did not see professor adams at that time, but i spent the whole of monday morning walking about the college with him. i asked him to show me the place where he made his computations for neptune, and he was evidently well pleased to do so. "we laughed over a roll, which we saw in the college library, containing a list of the ancestors of henry viii.; among them was jupiter. "professor adams tells me that in wales genealogical charts go so far back that about half-way between the beginning and the present day you find this record: 'about this time the world was created'! "november 2. at lunch to-day dr. whewell was more interesting than i had seen him before. he asked me about laura bridgman, and said that he knew a similar case. he contended, in opposition to mrs. airy and myself, that loss of vision was preferable to loss of hearing, because it shut one out less from human companionship. "dr. whewell's self-respect and immense self-esteem led him to imperiousness of manner which touches the border of discourtesy. he loves a good joke, but his jests are serious. he writes verses that are touchingly beautiful, but it is difficult to believe, in his presence, that he writes them. mrs. airy said that dr. whewell and i _riled_ each other! "i was at an evening party, and the airy boys, young men of eighteen and twenty, were present. they stood the whole time, occasionally leaning against a table or the piano, in their blue silk gowns. i urged them to sit. 'of course not,' they said; 'no undergraduate sits in the master's presence!' "i went to three services on 'scarlet sunday,' for the sake of seeing all the sights. "the costumes of cambridge and oxford are very amusing, and show, more than anything i have seen, the old-fogyism of english ways. dr. whewell wore, on this occasion, a long gown reaching nearly to his feet, of rich scarlet, and adorned with flowing ribands. the ribands did not match the robe, but were more of a crimson. "i wondered that a strong-minded man like dr. whewell could tolerate such trappings for a moment; but it is said that he is rather proud of them, and loves all the etiquette of the olden time, as also, it is said, does the queen. "in these robes dr. whewell escorted me to church--and of course we were a great sight! "before dinner, on this scarlet sunday, there was an interval when the master was evidently tried to know what to do with me. at length he hit upon an expedient. 'boys,' he said to the young airys, 'take miss mitchell on a walk!' "i was a little surprised to find myself on a walk, 'nolens volens;' so as soon as we were out of sight of the master of trinity, i said, 'now, young gentlemen, as i do not want to go to walk, we won't go!' "it was hard for me to become accustomed to english ideas of caste. i heard professor sedgwick say that miss herschel, the daughter of sir john and niece to caroline, married a gordon. 'such a great match for her!' he added; and when i asked what match could be great for a daughter of the herschels, i was told that she had married one of the queen's household, and was asked to _sit_ in the presence of the queen! "when i hear a missionary tell that the pariah caste sit on the ground, the peasant caste lift themselves by the thickness of a leaf, and the next rank by the thickness of a stalk, it seems to me that the heathen has reached a high state of civilization--precisely that which victoria has reached when she permits a herschel to sit in her presence! "the university of cambridge consists of sixteen colleges. i was told that, of these, trinity leads and st. john comes next. "trinity has always led in mathematics; it boasts of newton and byron among its graduates. milton belonged to christ church college; the mulberry tree which he planted still flourishes. "even to-day, a young scholar of trinity expressed his regret to me that milton did not belong to the college in which he himself studied. he pointed out the rooms occupied by newton, and showed us 'newton's bridge,' 'which will surely fall when a greater man than he walks over it'! "milton first planned the great poem, 'paradise lost,' as a drama, and this manuscript, kept within a glass case, is opened to the page on which the _dramatis personae_ are planned and replanned. on the opposite page is a part of 'lycidas,' neatly written and with few corrections. "the most beautiful of the college buildings is king's chapel. a cambridge man is sure to take you to one of the bridges spanning the wretched little stream called the 'silver cam,' that you may see the architectural beauties of this building. "it is well to attend service in one or the other of the chapels, to see assembled the young men, who are almost all the sons of the nobility or gentry. the propriety of their conduct struck me. "the fellows of the colleges are chosen from the 'scholars' who are most distinguished, as the 'scholars' are chosen from the undergraduates. they receive an income so long as they remain connected with the college and unmarried. "they have also the use of rooms in the college; they dine in the same hall with the undergraduates, but their tables are placed upon a raised dais; they have also little garden-places given them. "'what are their duties?' i asked mr. airy. 'none at all; _they_ are the college. it would not be a seat of learning without them.' "they say in cambridge that dr. whewell's book, 'plurality of worlds,' reasons to this end: the planets were created for this world; this world for man; man for england; england for cambridge; and cambridge for dr. whewell! "ambleside, september 13. we have spent the sunday in ascending a mountain, i have a minute route marked out for me by professor airy, who has rambled among the lakes and mountains of cumberland and westmoreland for months, and says that no man lives who knows them better than he. "in accordance with these directions, i took a one-horse carriage this morning for coniston waters, in order to ascend the 'old man.' the waiter at the 'salutation' at ambleside, which we made headquarters, told me that i could not make the ascent, as the day would not be fine; but i have not travelled six months for nothing, and i knew he was saying, 'you are fine american geese; you are not to leave my house until you have been well plucked!'--which threat he will of course keep, but i shall see all the 'old men' that i choose. so i borrowed the waiter's umbrella, when he said it would rain, and off we went in an open carriage, a drive of seven miles, up hill and down dale, among mountains and around ponds (lakes _they_ called them), in the midst of rich lands and pretty mansions, with occasionally a castle, and once a ruin, to diversify the scenery. "arrived at coniston hotel, the waiter said the same thing: 'it's too cloudy to ascend the "old man;"' but as soon as it was found that if it was too cloudy we did not intend to stay, it cleared off amazingly fast, and the ponies were ordered. i thought at first of walking up, but, having a value for my feet and not liking to misuse them, i mounted a pony and walked him. "he was beautifully stupid, but i could not help thinking of henry colman, the agriculturist, who, when in england, went on a fox-hunt. he said, 'think of my poor wife's old husband leaping a fence!' "but i soon forgot any fear, for the pony needed nothing from me or the guide, but scrambled about any way he chose; and the scenery was charming, for although the mountains are not very high, they are thrown together very beautifully and remind me of those of the hudson highlands. then the little lakes were lovely, and occasionally we came to a tarn or pond, and exceedingly small waterfalls were rushing about everywhere, without any apparent object in view, but evidently looking for something. and spite of the weatherwise head-waiter of the 'salutation' and of him of coniston inn, the day was beautiful. we had to give up the ponies when we were half a mile from the top, and clamber up ourselves. the guide was very intelligent, and pointed out the lakes, windermere, coniston; and the mountains, helvellyn, skiddaw, and saddleback; but at one time he spoke a name that i couldn't understand, and forgetting that i was in england and not in america, i asked him to _spell_ it. he replied, 'theys call it so always.' he did not fail, however, to ask questions like a yankee, if he couldn't spell like one. 'which way be ye coming?'--'from america.'--'ye'll be going to scotland like?'--'yes.'--'ye'll be spending much money before ye are home again.' "when we were quite on top of the mountain i asked what the white glimmering was in the distance, and he said it was, what i supposed, an arm of the sea. "the shadows of the flying clouds were very pretty falling on the hills around us, and the villages in the valleys beneath looked like white dots on the green. "sunday, sept. 20, 1857. we have been to see miss southey to-day. i sent the letter which mrs. airy gave me yesterday, and with it a note saying that i would call to-day if convenient. "miss southey replied at once, saying that she should be happy to see me. she lives in a straggling, irregular cottage, like most of the cottages around keswick, but beautifully situated, though far from the lake. "southey himself lived at greta hall, a much finer place, for many years, but he never owned it, and the gentleman who bought it will permit no one to see it. "miss southey's house is overgrown with climbing plants, has windows opening to the ground, and is really a summer residence, not a good winter home. "when southey, in his decline, married a second wife, the family scattered, and this daughter, the only unmarried one, left him. "we were shown into a pleasant parlor comfortably furnished, especially with books and engravings, portraits of southey, wordsworth, and others. "miss southey soon came down; she is really pretty, having the fresh english complexion and fair hair. she seems to be a very simple, pleasant person; chatty, but not too much so. she is much engrossed by the care of three of her brother's children, an old aunt, and a servant, who, having been long in the family, has become a dependant. miss southey spoke at once of the americans whom she had known, ticknor being one. "the old aunt asked after a new york lady who had visited southey at greta hall, but her niece reminded her that it must have been before i was born! "miss southey said that her father felt that he knew as many americans as englishmen, and that she wanted very much to go to america. i told her that she would be in danger of being 'lionized;' she said, 'oh, i should like that, for of course it is gratifying to know how much my father was valued there." "i asked after the children, and miss southey said that the little boy had called out to her, 'oh! aunt katy, the ameriky ladies have come! "the three children were called in; the boy, about six years old, of course wouldn't speak to me. "the best portrait of southey in his daughter's collection is a profile in wax--a style that i have seen several times in england, and which i think very pretty. "we went down to lodore, the scene of the poem, 'how does the water come down,' etc., and found it about as large as the other waterfalls around here--a little dripping of water among the stones. collingwood, nov. 14, 1857. my dear father: this is sir john herschel's place. i came last night just at dusk. according to english ways, i ought to have written a note, naming the hour at which i should reach etchingham, which is four miles from collingwood; but when i left liverpool i went directly on, and a letter would have arrived at the same time that i did. i stopped in london one night only, changed my lodging-house, that i might pay a pound a week only for letting my trunk live in a room, instead of two pounds, and started off again. i reached etchingham at ten minutes past four, took a cab, and set off for sir john's. it is a large brick house, no way handsome, but surrounded by fine grounds, with beautiful trees and a very large pond. the family were at dinner, and i was shown into the drawing-room. there was just the light of a coal fire, and as i stood before it sir john bustled in, an old man, much bent, with perfectly white hair standing out every way. he reached both hands to me, and said, "we had no letter and so did not expect you, but you are always welcome in this house." lady herschel followed--very noble looking; she does not look as old as i, but of course must be; but english women, especially of her station, do not wear out as we do, who are "jacks at all trades." i found a fire in my room, and a cup of tea and crackers were immediately sent up. the herschels have several children; i have not seen caroline, louise, william, and alexander, but belle, and amelie, and marie, and julie, and rosa, and francesca, and constance, and john are at home! the children are not handsome, but are good-looking, and well brought up of course, and highly educated. the children all come to table, which is not common in england. think what a table they must set when the whole twelve are at home! the first object that struck me in the house was borden's map of massachusetts, hanging in the hall opposite the entrance. over the mantelpiece in the dining-room is a portrait of sir william herschel. in the parlor is a portrait of caroline herschel, and busts of sir william, sir john, and the eldest daughter. i spent the evening in looking at engravings, sipping tea, and talking. sir john is like the elder mr. bond, except that he talks more readily; but he is womanly in his nature, not a tyrant like whewell. sir john is a better listener than any man i have met in england. he joins in all the chit-chat, is one of the domestic circle, and tells funny little anecdotes. (so do whewell and airy.) the herschels know abbot lawrence and edward everett--and everywhere these two have left a good impression. but i am certainly mortified by anecdotes that i hear of "pushing" americans. mrs. ---sought an introduction to sir john herschel to tell him about an abridgment of his astronomy which she had made, and she intimated to him that in consequence of her abridgment his work was, or would be, much more widely known in america. lady herschel told me of it, and she remarked, "i believe sir john was not much pleased, for he does not like abridgments." i told her that i had never heard of the abridgment. there are other guests in the house: a lady whose sister was among those killed in india; and her husband, who is an officer in the army. we have all been playing at "spelling" this evening, with the letters, as we did at home last winter. sunday, 15th. i thought of going to london to-day, but was easily persuaded to stay and go with lady herschel to-morrow. all this afternoon i have spent listening to sir john, who has shown me his father's manuscript, his aunt's, beautifully neat, and he told me about his cape observations. the telescope used at the cape of good hope lies in the barn (the glass, of course, taken care of) unused; and sir john now occupies himself with writing only. he made many drawings at the cape, which he showed me, and very good ones they are. lady herschel offers me a letter to mrs. somerville, who is godmother to one of her children. i am afraid i shall have no letter to leverrier, for every one seems to dislike him. lady herschel says he is one of the few persons whom she ever asked for an autograph; he was her guest, and he refused! just as i was coming away, sir john bustled up to me with a sheet of paper, saying that he thought i would like some of his aunt's handwriting and he would give it to me. he had before given me one of his own calculations; he says if there were no "war, pestilence, or famine," and one pair of human beings had been put upon the globe at the time of cheops, they would not only now fill the earth, but if they stood upon each other's heads, they would reach a hundred times the distance to neptune! i turned over their scrap-books, and sir john's poetry is much better than many of the specimens they had carefully kept, by sir william hamilton. sir william hamilton's sister had some specimens in the book, and also lady herschel and her brother. lady herschel is the head of the house--so is mrs. airy--so, i suspect, is the wife in all well-ordered households! i perceived that sir john did not take a cup of tea until his wife said, "you can have some, my dear." mr. airy waits and waits, and then says, "my dear, i shall lose all my flesh if i don't have something to eat and drink." i am hoping to get to paris next week, about the 23d. i have had just what i wanted in england, as to society. "november 26. a few days ago i received a card, 'mrs. baden powell, at home november 25.' of course i did not know if it was a tea party or a wedding reception. so i appealed to mrs. airy. she said, 'it is a london rout. i never went to one, but you'll find a crowd and a good many interesting people.' "i took a cab, and went at nine o'clock. the servant who opened the door passed me to another who showed me the cloak-room. the girl who took my shawl numbered it and gave me a ticket, as they would at a public exhibition. then she pointed to the other end of the room, and there i saw a table with tea and coffee. i took a cup of coffee, and then the servant asked my name, _yelled_ it up the stairs to another, and he announced it at the drawing-room door just as i entered. "mrs. powell and the professor were of course standing near, and mrs. admiral smyth just behind. to my delight, i met four english persons whom i knew, and also prof. henry b. rogers, who is a great society man. "people kept coming until the room was quite full. i was very glad to be introduced to professor stokes, who is called the best mathematician in england, and is a friend of adams. he is very handsome--almost all englishmen are handsome, because they look healthy; but professor stokes has fine black eyes and dark hair and good features. he looks very young and innocent. stokes is connected with cambridge, but lives in london, just as professor powell is connected with oxford, but also lives in london. several gentlemen spoke to me without a special introduction--one told me his name was dr. townby [qy., toynbie], and he was a great admirer of emerson--the first case of the sort i have met. "dr. townby is a young man not over thirty, full of enthusiasm and progress, like an american. he really seemed to me all alive, and is either a genius or crazy--the shade between is so delicate that i can't always tell to which a person belongs! i asked him if babbage was in the room, and he said, 'not yet,' so i hoped he would come. "he told me that a fine-looking, white-headed, good-featured old man was roget, of the 'thesaurus;' and another old man in the corner was dr. arnott, of the 'elements of physics.' i had supposed he was dead long ago. afterwards i was introduced to him. he is an old man, but not much over sixty; his hair is white, but he is full of vigor, short and stout, like almost all englishmen and englishwomen. i have met only two women taller than myself, and most of them are very much shorter. dr. arnott told me he was only now finishing the 'elements,' which he first published in 1827. he intends now to publish the more mathematical portions with the other volumes. he was very sociable, and i told him he had twenty years ago a great many readers in america. he said he supposed he had more there than in england, and that he believed he had made young men study science in many instances. "i asked him if babbage was in the room, and he too said, 'not yet.' dr. arnott asked me if i wore as many stockings when i was observing as the herschels--he said sir william put on twelve pairs and caroline fourteen! "i stayed until eleven o'clock, then i said 'good-by,' and just as i stepped upon the threshold of the drawing-room to go out, a broad old man stepped upon it, and the servant announced 'mr. babbage,' and of course that glimpse was all i shall ever have! "edinboro', september 30. the people of edinboro', having a passion for grecian architecture, and being very proud of the athenian character of their city, seek to increase the resemblance by imitations of ancient buildings. "grecian pillars are seen on calton hill in great numbers, and the observatory would delight an old greek; its four fronts are adorned by grecian pillars, and it is indeed beautiful as a structure; but the greeks did not build their temples for astronomical observations; they probably adapted their architecture to their needs. "this beautiful building was erected by an association of gentlemen, who raised a good deal of money, but, of course, not enough. they built the grecian temple, but they could not supply it with priests. "about a hundred years ago colin maclaurin had laid the foundation of an observatory, and the curious gothic building, which still stands, is the first germ. we laugh now at the narrow ideas of those days, which seemed to consider an observatory a lookout only; but the first step in a work is a great step--the others are easily taken. there was added to the building of maclaurin a very small transit room, and then the present edifice followed. "when the builders of the observatory found that they could not support it, they presented it to the british government; so that it is now a government child, but it is not petted, like the first-born of greenwich. "there are three instruments; an excellent transit instrument of six and a half inches' aperture, resting on its y's of solid granite. the corrections of the errors of the instrument by means of little screws are given up, and the errors which are known to exist are corrected in the computations. "professor smyth finds that although the two pillars upon which the instrument rests were cut from the same quarry, they are unequally affected by changes of temperature; so that the variation of the azimuth error, though slight, is irregular. "the collimation plate they correct with the micrometer, so that they consider some position-reading of the micrometer-head the zero point, and correct that for the error, which they determine by reflection in a trough of mercury. with this instrument they observe on certain stars of the british catalogue, whose places are not very well determined, and with a mural circle of smaller power they determine declinations. "the observatory possesses an equatorial telescope, but it is of mixed composition. the object glass was given by dr. lee, the eye-pieces by some one else, and the two are put together in a case, and used by professor smyth for looking at the craters in the moon; of these he has made fine drawings, and has published them in color prints. "the whole staff of the observatory consists of professor smyth, mr. wallace, an old man, and mr. williamson, a young man. "the city of edinboro' has no amateur astronomers, and there are two only, of note, in scotland: sir william bisbane and sir william keith murray. "from the observatory, the view of edinboro' is lovely. 'auld reekie,' as the scotch call it, always looks her best through a mist, and a scotch mist is not a rare event--so we saw the city under its most becoming veil. "october, 1857. i stopped in glasgow a few hours, and went to the observatory, which is also the private residence of professor nichol. miss nichol received me, and was a very pleasant, blue-eyed young lady. "i found that the observatory boasts of two good instruments: a meridian circle, which must be good, from its appearance, and a newtonian telescope, differently mounted from any i had seen; cased in a composition tube which is painted bright blue--rather a striking object. the iron mounting seemed to me good. it was of the german kind, but modified. it seemed to me that it could be used for observations far from the meridian. the iron part was hollow, so that the clock was inside, as was the azimuth circle, and thus space was saved. "they have a wind and rain self-register, and a self-registering barometer, marking on a cylinder turned by a clock, the paper revolving once an hour. "when i was at dungeon ghyll, a little ravine among the english lakes, down which trickles an exceedingly small stream of water, but which is, nevertheless, very picturesque,--as i followed the old man who shows it for a sixpence, he asked if we had come a long way. 'from america,' i replied. 'we have many americans here,' said he; 'it is much easier to understand their language than that of other foreigners; they speak very good english, better than the french or germans.' "i felt myself a little annoyed and a good deal amused. i supposed that i spoke the language that addison wrote, and here was a westmoreland guide, speaking a dialect which i translated into english before i could understand it, complimenting me upon my ability to speak my own tongue. "i learned afterwards, as i journeyed on, to expect no appreciation of my country or its people. the english are strangely deficient in curiosity. i can scarcely imagine an englishwoman a gossip. "i found among all classes a knowledge of the extent of america; by the better classes its geography was understood, and its physical peculiarities. one astronomer had bound the scientific papers from america in green morocco, as typical of a country covered by forests. among the most intelligent men whom i met i found an appreciation of the different characters of the states. everywhere massachusetts was honored; everywhere i met the horror of the honest englishman at the slave system; but anything like a discriminating knowledge of our public men i could not meet. webster had been heard of everywhere. they assured me that our _really great_ men were known, our really great deeds appreciated; but this is not true. they make mistakes in their measure of our men; second-rate men who have travelled are of course known to the men whom they have met; these travellers have not perhaps thought it necessary to mention that they represent a secondary class of people, and they are considered our 'first men.' the english forget that all americans travel. "i was vexed when i saw some of our most miserable novels, bound in showy yellow and red, exposed for sale. a friend told me that they had copied from the cheap publications of america. it may be so, but they have outdone us in the cheapness of the material and the showy covers. i never saw yellow and red together on any american book. "the english are far beyond us in their highest scholarship, but why should they be ignorant of our scholars? the englishman is proud, and not without reason; but he may well be proud of the american offshoot. it is not strange that england produces fine scholars, when we consider that her colleges confer fellowships on the best undergraduates. "england differs from america in the fact that it has a past. well may the great men of the present be proud of those who have gone before them; it is scarcely to be hoped that the like can come after them; and yet i suppose we must admit that even now the strong minds are born across the water. "at the same time england has a class to which we have happily no parallel in our country--a class to which even english gentlemen liken the sepoys, and who would, they admit, under like circumstances be guilty of like enormities. but the true englishman shuts his eyes for a great part of the time to the steps in the social scale down which his race descends, and looks only at the upper walks. he has therefore a glance of patronizing kindness for the people of the united states, and regards us of new england as we regard our rich brethren of the west. "i wondered what was to become of the english people! their island is already crowded with people, the large towns are numerous and are very large. suppose for an instant that her commerce is cut off, will they starve? it is an illustration of moral power that, little island as that of great britain is, its power is the great power of the world. "crowded as the people are, they are healthy. i never saw, i thought, so many ruddy faces as met me at once in liverpool. dirty children in the street have red cheeks and good teeth. nowhere did i see little children whose minds had outgrown their bodies. they do not live in the school-room, but in the streets. one continually meets little children carrying smaller ones in their arms; little girls hand in hand walk the streets of london all day. there are no free schools, and they have nothing to do. beggars are everywhere, and as importunate as in italy. for a well-behaved common people i should go to paris; for clean working-women i should look in paris. "i saw a little boy in england tormenting a smaller one. he spat upon his cap, and then declared that the little one did it. the little one sobbed and said he didn't. i gave the little one a penny; he evidently did not know the value of the coin, and appealed to the bigger boy. 'is it a penny?' he asked, with a look of amazement. 'yes,' said the bigger. off ran the smaller one triumphant, and the bigger began to cry, which i permitted him to do." chapter vii 1857-1858 first european tour continued--leverrier and the paris observatory--rome--harriet hosmer--observatory of the collegio romano--secchi at this time, the feeling between astronomers of great britain and those of the united states was not very cordial. it was the time when adams and leverrier were contending to which of them belonged the honor of the discovery of the planet neptune, and each side had its strong partisans. among miss mitchell's papers we find the following with reference to this subject: "... adams, a graduate of cambridge, made the calculations which showed how an unseen body must exist whose influences were felt by uranus. it was a problem of great difficulty, for he had some half-dozen quantities touching uranus which were not accurately known, and as many wholly unknown concerning the unseen planet. we think it a difficult question which involves three or four unknown quantities with too few circumstances, but this problem involved twelve or thirteen, so that x, y, z reached pretty high up into the alphabet. but adams, having worked the problem, carried his work to airy, the astronomer royal of england, and awaited his comments. a little later leverrier, the french astronomer, completed the same problem, and waiting for no authority beyond his own, flung his discovery out to the world with the self-confidence of a frenchman.... "... when the news of the discovery of neptune reached this country, i happened to be visiting at the observatory in cambridge, mass. professor bond (the elder) had looked for the planet the night before i arrived at his house, and he looked again the evening that i came. "his observatory was then a small, round building, and in it was a small telescope; he had drawn a map of a group of stars, one of which he supposed was not a star, but the planet. he set the telescope to this group, and asking his son to count the seconds, he allowed the stars to pass by the motion of the earth across the field. if they kept the relative distance of the night before, they were all stars; if any one had approached or receded from the others, it was a planet; and when the father looked at his son's record he said, 'one of those has moved, and it is the one which i thought last night was the planet.' he looked again at the group, and the son said, 'father, do give me a look at the new planet--you are the only man in america that can do it!' and then we both looked; it looked precisely like a small star, and george and i both asked, 'what made you think last night that it was the new planet?' mr. bond could only say, 'i don't know, it looked different from the others.' "it is always so--you cannot get a man of genius to explain steps, he leaps. "after the discovery of this planet, professor peirce, in our own country, declared that it was not the planet of the theory, and therefore its discovery was a happy accident. but it seemed to me that it was the planet of the theory, just as much if it varied a good deal from its prescribed place as if it varied a little. so you might have said that uranus was not the uranus of the theory. "sir john herschel said, 'its movements have been felt trembling along the far-reaching line of our analysis, with a certainty hardly inferior to ocular demonstration.' i consider it was superior to ocular demonstration, as the action of the mind is above that of the senses. adams, in his study at cambridge, england, and leverrier in his closet at paris, poring over their logarithms, knew better the locus of that outside planet than all the practical astronomers of the world put together.... "of course in paris i went to the imperial observatory, to visit leverrier. i carried letters from professor airy, who also sent a letter in advance by post. leverrier called at my hotel, and left cards; then came a note, and i went to tea. "leverrier had succeeded arago. arago had been a member of the provisional government, and had died. leverrier took exactly opposite ground, politically, to that of arago; he stood high with the emperor. "he took me all over the observatory. he had a large room for a ballroom, because in the ballroom science and politics were discussed; for where a press is not free, salons must give the tone to public opinion. "both leverrier and madame leverrier said hard things about the english, and the english said hard things about leverrier. "the astronomical observatory of paris was founded on the establishment of the academy of sciences, in the reign of louis xiv. the building was begun in 1667 and finished in 1672; like other observatories of that time, it was quite unfit for use. "john dominie cassini came to it before it was finished, saw its defects, and made alterations; but the whole building was afterwards abandoned. m. leverrier showed me the transit instrument and the mural circle. he has, like mr. airy, made the transit instrument incapable of mechanical change for its corrections of error, so that it depends for accuracy upon its faults being known and corrected in the computations. "all the early observatories of europe seem to have been built as temples to urania, and not as working-chambers of science. the royal observatory at greenwich, the imperial observatory of paris, and the beautiful structure on calton hill, edinboro', were at first wholly useless as observatories. that of greenwich had no steadiness, while every pillar in the astronomical temple of edinboro', though it may tell of the enlightenment of greece, hides the light of the stars from the scottish observer. well might struve say that 'an observatory should be simply a box to hold instruments.' "the leverriers speak english about as well as i do french, and we had a very awkward time of it. m. leverrier talked with me a little, and then talked wholly to one of the gentlemen present. madame was very chatty. "leverrier is very fine-looking; he is fair-haired full-faced, altogether very healthy-looking. his wife is really handsome, the children beautiful. i was glad that i could understand when leverrier said to the children, 'if you make any more noise you go to bed.' "while i was there, a woman as old as i rushed in, in bonnet and shawl, and flew around the room, kissed madame, jumped the children about, and shook hands with monsieur; and there was a great amount of screaming and laughing, and all talked at once. as i could not understand a word, it seemed to me like a theatre. "i asked monsieur when i could see the observatory, and he answered, 'whenever it suits your convenience.' "december 15. i went to leverrier's again last evening by special invitation. four gentlemen and three ladies received me, all standing and bowing without speaking. monsieur was, however, more sociable than before, and shrieked out to me in french as though i were deaf. "the ladies were in blue dresses; a good deal of crinoline, deep flounces, high necks, very short, flowing sleeves, and short undersleeves; the dresses were brocade and the flounces much trimmed, madame's with white plush. "the room was cold, of course, having no carpet, and a wood fire in a very small fireplace. "the gentlemen continued standing or promenading, and taking snuff. "except leverrier, no one of them spoke to me. the ladies all did, and all spoke french. the two children were present again--the little girl five years old played on the piano, and the boy of nine played and sang like a public performer. he promenaded about the room with his hands in his pockets, like a man. i think his manners were about equal to -----'s, as occasionally he yelled and was told to be quiet. "about ten o'clock m. leverrier asked me to go into the observatory, which connects with the dwelling. they are building immense additional rooms, and are having a great telescope, twenty-seven feet in focal length, constructed. "with leverrier's bad english and my bad french we talked but little, but he showed me the transit instrument, the mural circle, the computing-room, and the private office. he put on his cloak and cap, and said, 'voila le directeur!' "one room, he told me, had been arago's, and arago had his bed on one side. m. leverrier said, 'i do not wish to have it for my room.' he is said to be much opposed to arago, and to be merciless towards his family. "he showed me another room, intended for a reception-room, and explained to me that in france one had to make science come into social life, for the government must be reached in order to get money. "there were huge globes in one room that belonged to cassini. if what he showed me is not surpassed in the other rooms, i don't think much of their instruments. "m. leverrier said he had asked m. chacornac to meet me, but he was not there. i felt that we got on a little better, but not much, and it was evident that he did not expect me to understand an observatory. we did not ascend to the domes. "leverrier has telegraphic communication with all europe except great britain. "it was quite singular that they made such different remarks to me. leverrier said that they had to make science popular. "airy said, 'in england there is no astronomical public, and we do not need to make science popular.' "jan. 24, 1858. i am in rome! i have been here four days, and already i feel that i would rather have that four days in rome than all the other days of my travels! i have been uncomfortable, cold, tired, and subjected to all the evils of travelling; but for all that, i would not have missed the sort of realization that i have of the existence of the past of great glory, if i must have a thousand times the discomfort. i went alone yesterday to st. peter's and the vatican, and today, taking murray, i went alone to the roman forum, and stood beside the ruined porticos and the broken columns of the temple. then i pushed on to the coliseum, and walked around its whole circumference. i could scarcely believe that i really stood among the ruins, and was not dreaming! i really think i had more enjoyment for going alone and finding out for myself. afterwards the hawthornes called, and i took mrs. h. to the same spot.... "i really feel the impressiveness of rome. all europe has been serious to me; rome is even sad in its seriousness. you cannot help feeling, in the coliseum, some little of the influence of the scenes that have been enacted there, even if you know little about them; you must remember that the vast numbers of people who have been within its walls for ages have not been common minds, whether they were christian martyrs or travelling artists.... "i think if i had never heard before of the reputation of the pictures and statues of the vatican, i should have perceived their superiority. there is more idea of _action_ conveyed by the statuary than i ever received before--they do not seem to be _dead_. "january 25. i have finer rooms than i had in paris, but the letting of apartments is better managed in paris. there you always find a _concierge_, who tells you all you want to know, and who speaks several languages. in rome you enter a narrow, dark passage, and look in vain for a door. then you go up a flight of stairs, and see a door with a string; you pull the string, and a woman puts her mouth to a square hole, covered with tin punctured with holes, and asks what you want. you tell her, and she tells you to go up higher; you repeat the process, and at last reach the rooms. the higher up the better, because you get some sun, and one learns the value of sunlight. i saw no sun in paris in my room, and here i have it half of the day, and it seems very pleasant. "all the customs of the people differ from those of paris.... "a little of italian art enters into the ornaments of rooms and furniture, but anything like mechanical skill seems to be unheard of; and i dare say the pretty stamp used on the butter i have, which represents some antique picture, was cut by some northern hand. i could make a better cart than those that i see on the streets, and i could _almost_ make as good horses as those that draw them!... "it is holy week. i have spent seven hours at a time at st. peter's, in terrible crowds, for ten days, and now i go no more. the ladies are seated, but as the ceremonies are in different parts of the immense building, they rush wildly from one to the other; with their black veils they look like furies let loose! i stayed five hours to-day to see the pope wash feet, which was very silly; for i saw mother wash them much more effectually twenty years ago! "the crowd is better worth seeing than the ceremony, if one could only see it without being in it. i shall not try to hear the 'miserere'--i have given up the study of music! since i failed to appreciate mario, i sha'n't try any more! "i go to the storys' on sunday evening to look at st. peter's lighting up. "march 21. i have been to vespers at st. peter's. they begin an hour before sunset. when my work is done for the day, i walk to st. peter's. this is sunday, and the floor was full of kneeling worshippers, but that makes no difference. i walk about among them. "i was there an hour to-day before i saw a person that i knew; then i met the nicholses and went with them into a side chapel to hear vespers. then i saw next the waterstons, then miss lander; but i was unusually short of friends, i generally meet so many more. "there were kneeling women to-day with babies in their arms. the babies of the lower classes have their legs so wrapped up that they cannot move them; they look like small pillows even when they are six months old. i think it must dwarf them. we americans are a tall people. i am a very tall woman here. i think that p.'s height would cause a sensation in the streets. my servant admires my height very much. "march 22. i called on miss bremer to-day, having heard that she desired to see me. she is a 'little woman in black,' but not so plain; her face is a little red, but her complexion is fair and the expression very pleasing. she chatted away a good deal; asked me about astronomy, and how i came to study it. i told her that my father put me to it, and she said she was just writing a story on the affection of father and daughter. she told me i had good eyes. it is a long time now since any one has told me that! "miss bremer and mrs. w. met in my room and remained an hour. miss bremer is quiet and unpretending. mrs. w. is flashy and brilliant, and, as i usually say when i don't understand a person, a little insane; she had the floor all the time after she came in. she gave a sketch of her life from her birth up, mentioning incidentally that she had been a belle, surrounded with beaux, the pride of her parents, with a reputation for intellect, etc. "i had been urging miss bremer into an interesting talk before mrs. w. appeared, and i felt what a pity it was that she hadn't the same propensity to talk that the latter had. she talked very pleasantly, however, and i thought what a pity it was that i shall not see her again; for i leave rome in three days for florence. "i was in rome for a winter, an idler by necessity for six weeks. it is the very place of all the world for an idler. "on the pleasant days there are the ruins to visit, the campagna to stroll over, the villas and their grounds to gather flowers in, the forum to muse in, the pincian hill or the capitoline for a gossiping walk with some friend. "on rainy days it is all art. there are the cathedrals, the galleries, and the studios of the thousand artists; for every winter there are a thousand artists in rome. "a rainy day found me in the studio of paul akers. as i was looking at some of his models, the studio door opened and a pretty little girl, wearing a jaunty hat and a short jacket, into the pockets of which her hands were thrust, rushed into the room, seemingly unconscious of the presence of a stranger, began a rattling, all-alive talk with mr. akers, of which i caught enough to know that a ride over the campagna was planned, as i heard mr. akers say, 'oh, i won't ride with you--i'm afraid to!' after which he turned to me and introduced harriet hosmer. "i was just from old conservative england, and i had been among its most conservative people. i had caught something of its old musty-parchment ideas, and the cricket-like manners of harriet hosmer rather troubled me. it took some weeks for me to get over the impression of her madcap ways; they seemed childish. "i went to her studio and saw 'puck,' a statue all fun and frolic, and i imagined all was fun to the core of her heart. "as a general rule, people disappoint you as you know them. to know them better and better is to know more and more weaknesses. harriet hosmer parades her weaknesses with the conscious power of one who knows her strength, and who knows you will find her out if you are worthy of her acquaintance. she makes poor jokes--she's a little rude--a good deal eccentric; but she is always _true_. "in the town where she used to live in massachusetts they will tell you a thousand anecdotes of her vagaries--but they are proud of her. "she does not start on a false scent; she knows the royal character of the game before she hunts. "a lady who is a great rider said to me a few days since: 'of course i do not ride like harriet hosmer, but, if you will notice, there is method in harriet hosmer's madness. she does not mount a horse until she has examined him carefully.' "at the time when i saw her, she was thinking of her statue of zenobia. she was studying the history of palmyra, reading up on the manners and customs of its people, and examining eastern relics and costumes. "if she heard that in the sacristy of a certain cathedral, hundreds of miles away, were lying robes of eastern queens, she mounted her horse and rode to the spot, for the sake of learning the lesson they could teach. "day after day alone in her studio, she studied the subject. think what knowledge of the country, of the history of the people, must be gathered, must be moulded, to bring into the face and bearing of its queen the expression of the race! think what familiar acquaintance with the human form, to represent a lifelike figure at all! "for years after i came home i read the newspapers to see if i could find any notice of the statue of zenobia; and i did at length see this announcement: 'the statue of zenobia, by miss hosmer, is on exhibition at childs & jenks'.' "it was after five years. all through those five years, miss hosmer had kept her projects steadily turned in this direction. "whatever may be the criticism of art upon her work, no one can deny that she is above the average artist. "but she is herself, as a woman, very much above herself in art. if there came to any struggling artist in rome the need of a friend,--and of the thousand artists in rome very few are successful,--harriet hosmer was that friend. "i knew her to stretch out a helping hand to an unfortunate artist, a poor, uneducated, unattractive american, against whom the other americans in rome shut their houses and their hearts. when the other americans turned from the unsuccessful artist, harriet hosmer reached forth the helping hand. "when harriet hosmer knew herself to be a sculptor, she knew also that in all america was no school for her. she must leave home, she must live where art could live. she might model her busts in the clay of her own soil, but who should follow out in marble the delicate thought which the clay expressed? the workmen of massachusetts tended the looms, built the railroads, and read the newspapers. the hard-handed men of italy worked in marble from the designs put before them; one copied the leaves which the sculptor threw into the wreaths around the brows of his heroes; another turned with his tool the folds of the drapery; another wrought up the delicate tissues of the flesh; none of them dreamed of ideas: they were copyists,--the very hand-work that her head needed. "and to italy she went. for her school she sought the studio of gibson--the greatest sculptor of the time. "she resolved 'to scorn delights and live laborious days;' and there she has lived and worked for years. "she fashions the clay to her ideal--every little touch of her fingers in the clay is a thought; she thinks in clay. "the model finished and cast in the dull, hard, inexpressive plaster, she stands by the workmen while they put it into the marble. she must watch them, for a touch of the tool in the wrong place might alter the whole expression of the face, as a wrong accent in the reader will spoil a line of poetry. "collegio romano; secchi. there was another observatory which had a reputation and was known in america. it was the observatory of the collegio romano, and was in the monastery behind the church of st. ignasio. its director was the father secchi who had visited the united states, and was well known to the scientists of this country. "i said to myself, 'this is the land of galileo, and this is the city in which he was tried. i knew of no sadder picture in the history of science than that of the old man, galileo, worn by a long life of scientific research, weak and feeble, trembling before that tribunal whose frown was torture, and declaring that to be false which he knew to be true. and i know of no picture in the history of religion more weakly pitiable than that of the holy church trembling before galileo, and denouncing him because he found in the book of nature truths not stated in their own book of god--forgetting that the book of nature is also a book of god. "it seems to be difficult for any one to take in the idea that two truths cannot conflict. "galileo was the first to see the four moons of jupiter; and when he announced the fact that four such moons existed, of course he was met by various objections from established authority. one writer declared that as astrologers had got along very well without these planets, there could be no reason for their starting into existence. "but his greatest heresy was this: he was tried, condemned, and punished for declaring that the sun was the centre of the system, and that the earth moved around it; also, that the earth turned on its axis. "for teaching this, galileo was called before the assembled cardinals of rome, and, clad in black cloth, was compelled to kneel, and to promise never again to teach that the earth moved. it is said that when he arose he whispered, 'it does move!' "he was tried at the hall of sopre minerva. in fewer than two hundred years from that time the church of st. ignasio was built, and the monastery on whose walls the instruments of the modern observatory stand. "it is a very singular fact, but one which seems to show that even in science 'the blood of the martyrs is the seed of the church,' that the spot where galileo was tried is very near the site of the present observatory, to which the pope was very liberal. "from the hall of sopre minerva you make but two turns through short streets to the fontenelle de borghese, in the rear of which stands the present observatory. "indeed, if a cardinal should, at the hall of sopre minerva, call out to secchi, 'watchman, what of the night?' secchi could hear the question; and no bolder views emanate from any observatory than those which secchi sends out. "i sent a card to secchi, and awaited a call, well satisfied to have a little more time for listless strolling among ruins and into the studios. and so we spent many an hour: picking up land shells from the top of the coliseum, gathering violets in the upper chambers of the palace of the caesars,--for the overgrown walls made climbing very easy,--or, resting upon some broken statue on the forum, we admired the arches of the temple of peace, thrown upon the rich blue of the sunny skies. "returning one day from a drive, i met two priests descending one of the upper flights of stairs in the house where i lived. as my rooms had been blessed once, and holy water sprinkled upon them, i thought perhaps another process of that kind had just been gone through, and was about to pass them, when one of them, accosting me, asked if i were the signorine mitchell,--changing his italian to good english as he saw that i was, and introducing himself as father secchi. he told me that the younger man was a young _religieux_, and the two turned and went back with me. "i recalled, as i saw father secchi, an anecdote i had heard, no way to his credit,--except for ingenious trickery. it was said that coming to america he brought with him the object-glass of a telescope, at a time when scientific apparatus paid a high duty. being asked by some official what the article was, he replied, 'my looking-glass,' and in that way passed it off as personal wardrobe, so escaped the duty. (it may have been de vico.) "father secchi had brought with him, to show me, negatives of the planet saturn,--the rings showing beautifully, although the image was not more than half an inch in size. "i was ignorant enough of the ways of papal institutions, and, indeed, of all italy, to ask if i might visit the roman observatory. i remembered that the days of galileo were days of two centuries since. i did not know that my heretic feet must not enter the sanctuary,--that my woman's robe must not brush the seats of learning. "the father's refusal was seen in his face at once, and i felt that i had done something highly improper. the father said that he would have been most happy to have me visit him, but he had not the power--it was a religious institution--he had already applied to his superior, who was not willing to grant permission--the power lay with the holy father or one of his cardinals. i was told that mrs. somerville, the most learned woman in all europe, had been denied admission; that the daughter of sir john herschel, in spite of english rank, and the higher stamp of nature's nobility, was at that time in rome, and could not enter an observatory which was at the same time a monastery. "if i had before been mildly desirous of visiting the observatory, i was now intensely anxious to do so. father secchi suggested that i should see cardinal antonelli in person, with a written application in my hand. this was not to be thought of--to ask an interview with the wily cardinal! from a letter to her father. ... i am working to get admitted to see the observatory, but it cannot be done without special permission from the pope, and i don't like to be "presented." if i can get permission without the humbug of putting on a black veil and receiving a blessing from pius, i shall; but i shrink from the formality of presentation. i know thou'd say "be presented." "our minister at that time had the reputation of being very careless of the needs and wishes of his countrymen, and i was not surprised to find a long delay. "in the course of my waiting, i had told my story to a young italian gentleman, the nephew of a monseigneur; a monseigneur being next in rank to a cardinal. he assured me that permission would never be obtained by our minister. "after a fortnight's waiting i received a permit, written on parchment, and signed by cardinal antonelli. "when the young italian next called, i held the parchment up in triumph, and boasted that minister ---had at length moved in the matter. the young man coolly replied, 'yes, i spoke to my uncle last evening, and asked him to urge the matter with cardinal antonelli; but for that it would never have come!' there had been 'red tape,' and i had not seen it. "at the same time that the formal missive was sent to me, a similar one was sent to father secchi, authorizing him to receive me. the father called at once to make the arrangements for my visit. i made the most natural mistake! i supposed that the doors which opened to one woman, opened to all, and i asked to take with me my italian servant, a quick-witted and bright-eyed woman, who had escorted me to and from social parties in the evening, and who had learned in these walks the names of the stars, receiving them from me in english, and giving back to me the sweet italian words; and who had come to think herself quite an astronomer. father secchi refused at once. he said i was to meet him at the church of st. ignasio at one and a half hours before ave marie, and he would conduct me through the church into the observatory. my servant might come into the church with me. the ave marie bell rings half an hour after sunset. "at the appointed time, the next fine day,--and all days seem to be fine,--we set out on our mission. "when we entered the church we saw, far in the distance, father secchi, standing just behind a pillar. he slipped out a little way, as much as to say, 'i await you,' but did not come forward to meet us; so the woman and i passed along through the rows of kneeling worshippers, by the strolling students, and past the lounging tourists--who, guide-book in hand, are seen in every foreign church--until we came to the standpoint from which the father had been watching us. "then the italian woman put up a petition, not one word of which i could understand, but the gestures and the pointing showed that she begged to go on and enter the monastery and see the observatory. father secchi said, 'no, the holy father gave permission to one only,' and alone i entered the monastery walls. "through long halls, up winding staircases, occasionally stopped by some priest who touched his broad hat and asked 'parlate italiano?' occasionally passed by students, often stopped by pictures on the walls,--once to be introduced to a professor; then through the library of the monastery, full of manuscripts on which monks had worked away their lives; then through the astronomical library, where young astronomers were working away theirs, we reached at length the dome and the telescope. "one observatory is so much like another that it does not seem worth while to describe father secchi's. this observatory has a telescope about the size of that at washington (about twelve inches). secchi had no staff, and no prescribed duties. the base of the observatory was the solid foundation of the old roman building. the church was built in 1650, and the monastery in part at that time, certainly the dome of the room in which was the meridian instrument. "the staircase is cut out of the old roman walls, which no roll of carriage, except that of the earthquake chariot, can shake. "having no prescribed duties, secchi could follow his fancies--he could pick up comets as he picked up bits of mosaic upon the roman forum. he learns what himself and his instruments can do, and he keeps to that narrow path. "he was at that time much interested in celestial photography. "italy must be the very paradise of astronomers; certainly i never saw objects so well before; the purity of the air must be very superior to ours. we looked at venus with a power of 150, but it was not good. jupiter was beautiful, and in broad daylight the belts were plainly seen. with low powers the moon was charming, but the air would not bear high ones. "father secchi said he had used a power of 2,000, but that 600 was more common. i have rarely used 400. saturn was exquisite; the rings were separated all around; the dusky ring could be seen, and, of course, the shadow of the ball upon the ring. "the spectroscopic method of observing starlight was used by secchi as early as by any astronomer. by this method the starlight is analyzed, and the sunlight is analyzed, and the two compared. if it does not disclose absolutely what are the peculiarities of starlight and sunlight, relatively, it traces the relationship. "in order to be successful in this kind of observation, the telescope must keep very accurately the motion of the earth in its axis; and so the papal government furnishes nice machinery to keep up with this motion,--the same motion for declaring whose existence galileo suffered! the two hundred years had done their work. "i should have been glad to stay until dark to look at nebulae, but the father kindly informed me that my permission did not extend beyond the daylight, which was fast leaving us, and conducting me to the door he informed me that i must make my way home alone, adding, 'but we live in a civilized country.' "i did not express to him the doubt that rose to my thoughts! the ave marie bell rings half an hour after sunset, and before that time i must be out of the observatory and at my own house." chapter viii 1858-1865 first european tour concluded--mrs. somerville--humboldt--mrs. mitchell's death--removal to lynn, mass.--present of an equatorial telescope-extracts from letters "i had no hope, when i went to europe, of knowing mrs. somerville. american men of science did not know her, and there had been unpleasant passages between the savants of europe and those of the united states which made my friends a little reluctant about giving me letters. "professor henry offered to send me letters, and said that among them should be one to mrs. somerville; but when his package came, no such letter appeared, and i did not like to press the matter,--indeed, after i had been in england i was not surprised at any amount of reluctance. they rarely asked to know my friends, and yet, if they were made known to them, they did their utmost. "so i went to europe with no letter to mrs. somerville, and no letter to the herschels. "i was very soon domesticated with the airys, and really felt my importance when i came to sleep in one of the round rooms of the royal observatory. i dared give no hint to the airys that i wanted to know the herschels, although they were intimate friends. 'what was i that i should love them, save for feeling of the pain?' but one fine day a letter came to mrs. airy from lady herschel, and she asked, 'would not miss mitchell like to visit us?' of course miss mitchell jumped at the chance! mrs. airy replied, and probably hinted that miss mitchell 'could be induced,' etc. "if the airys were old friends of mrs. somerville, the herschels were older. the airys were just and kind to me; the herschels were lavish, and they offered me a letter to mrs. somerville. "so, provided with this open sesame to mrs. somerville's heart, i called at her residence in florence, in the spring of 1858. "i sent in the letter and a card, and waited in the large florentine parlor. in the open fireplace blazed a wood fire very suggestive of american comfort--very deceitful in the suggestion, for there is little of home comfort in italy. "after some little delay i heard a footstep come shuffling along the outer room, and an exceedingly tall and very old man entered the room, in the singular head-dress of a red bandanna turban, approached me, and introduced himself as dr. somerville, the husband. "he was very proud of his wife, and very desirous of talking about her, a weakness quite pardonable in the judgment of one who is desirous to know. he began at once on the subject. mrs. somerville, he said, took great interest in the americans, for she claimed connection with the family of george washington. "washington's half-brother, lawrence, married anne fairfax, who was one of the scotch family. when lieutenant fairfax was ordered to america, washington wrote to him as a family relative, and asked him to make him a visit. lieutenant fairfax applied to his commanding officer for permission to accept, and it was refused. they never met, and much to the regret of the fairfax family the letter of washington was lost. the fairfaxes of virginia are of the same family, and occasionally some member of the american branch returns to see his scotch cousins. "while dr. somerville was eagerly talking of these things, mrs. somerville came tripping into the room, speaking at once with the vivacity of a young person. she was seventy-seven years old, but appeared twenty years younger. she was not handsome, but her face was pleasing; the forehead low and broad; the eyes blue; the features so regular, that in the marble bust by chantrey, which i had seen, i had considered her handsome. "neither bust nor picture, however, gives a correct idea of her, except in the outline of the head and shoulders. "she spoke with a strong scotch accent, and was slightly affected with deafness, an infirmity so common in england and scotland. "while mrs. somerville talked, the old gentleman, seated by the fire, busied himself in toasting a slice of bread on a fork, which he kept at a slow-toasting distance from the coals. an english lady was present, learned in art, who, with a volubility worthy of an american, rushed into every little opening of mrs. somerville's more measured sentences with her remarks upon recent discoveries in _her_ specialty. whenever this occurred, the old man grew fidgety, moved the slice of bread backwards and forwards as if the fire were at fault, and when, at length, the english lady had fairly conquered the ground, and was started on a long sentence, he could bear the eclipse of his idol no longer, but, coming to the sofa where we sat, he testily said, 'mrs. somerville would rather talk on science than on art.' "mrs. somerville's conversation was marked by great simplicity; it was rather of the familiar and chatty order, with no tendency to the essay style. she touched upon the recent discoveries in chemistry or the discovery of gold in california, of the nebulae, more and more of which she thought might be resolved, and yet that there might exist nebulous matters, such as compose the tails of comets, of the satellites, of the planets, the last of which she thought had other uses than as subordinates. she spoke with disapprobation of dr. whewell's attempt to prove that our planet was the only one inhabited by reasoning beings; she believed that a higher order of beings than ourselves might people them. "on subsequent visits there were many questions from mrs. somerville in regard to the progress of science in america. she regretted, she said, that she knew so little of what was done in our country. "from lieutenant maury, alone, she received scientific papers. she spoke of the late dr. (nathaniel) bowditch with great interest, and said she had corresponded with one of his sons. she asked after professor peirce, whom she considered a great mathematician, and of the bonds, of cambridge. she was much interested in their photography of the stars, and said it had never been done in europe. at that time photography was but just applied to the stars. i had carried to the royal astronomical society the first successful photograph of a star. it was that of mizar and alcor, in the great bear. (since that time all these things have improved.) "the last time i saw mrs. somerville, she took me into her garden to show me her rose-bushes, in which she took great pride. mrs. somerville was not a mathematician only, she spoke italian fluently, and was in early life a good musician. "i could but admire mrs. somerville as a woman. the ascent of the steep and rugged path of science had not unfitted her for the drawing-room circle; the hours of devotion to close study have not been incompatible with the duties of wife and mother; the mind that has turned to rigid demonstration has not thereby lost its faith in those truths which figures will not prove. 'i have no doubt,' said she, in speaking of the heavenly bodies, 'that in another state of existence we shall know more about these things.' "mrs. somerville, at the age of seventy-seven, was interested in every new improvement, hopeful, cheery, and happy. her society was sought by the most cultivated people in the world. [she died at ninety-two.] "berlin, may 7, 1858. humboldt had replied to my letter of introduction by a note, saying that he should be happy to see me at 2 p.m., may 7. of course i was punctual. humboldt is one of several residents in a very ordinary-looking house on oranienberge strasse. "all along up the flight of stairs to his room were printed notices telling persons where to leave packages and letters for alexander humboldt. "the servant showed me at first into a sort of anteroom, hung with deers' horns and carpeted with tigers' skins, then into the study, and asked me to take a seat on the sofa. the room was very warm; comfort was evidently carefully considered, for cushions were all around; the sofa was handsomely covered with worsted embroidery. a long study-table was full of books and papers. "i had waited but a few moments when humboldt came in; he was a smaller man than i had expected to see. he was neater, more 'trig,' than the pictures represent him; in looking at the pictures you feel that his head is too large,--out of proportion to the body,--but you do not perceive this when you see him. "he bowed in a most courtly manner, and told me he was much obliged to me for coming to see him, then shook hands, and asked me to sit, and took a chair near me. "there was a clock in sight, and i stayed but half an hour. he talked every minute, and on all kinds of subjects: of dr. bache, who was then at the head of the u.s. coast survey; of dr. gould, who had recently returned from long years in south america; of the washington observatory and its director, lieutenant maury; of the dudley observatory, at albany; of sir george airy, of the greenwich observatory; of professor enke's comet reputation; of argelander, who was there observing variable stars; of mrs. somerville and goldschmidt, and of his brother. "it was the period when the subject of admitting kansas as a slave state was discussed--he touched upon that; it was during the administration of president buchanan, and he talked about that. "having been nearly a year in europe, i had not kept up my reading of american newspapers, but humboldt could tell me the latest news, scientifically and politically. to my ludicrous mortification, he told me of the change of position of some scientific professor in new york state, and when i showed that i didn't know the location of the town, which was clinton, he told me if i would look at the map, which lay upon the table, i should find the town somewhere between albany and buffalo. "humboldt was always considered a good-tempered, kindly-natured man, but his talk was a little fault-finding. "he said: 'lieutenant maury has been useful, but for the director of an observatory he has put forth some strange statements in the 'geography of the sea.' "he asked me if mrs. somerville was now occupied with pure mathematics. he said: 'there she is strong. i never saw her but once. she must be over sixty years old.' in reality she was seventy-seven. he spoke with admiration of mrs. somerville's 'physical geography,'--said it was excellent because so concise. 'a german woman would have used more words.' "humboldt asked me if they could apply photography to the small stars--to the eighth or ninth magnitude. i had asked the same question of professor bond, of cambridge, and he had replied, 'give me $500,000, and we can do it; but it is very expensive.' "humboldt spoke of the fifty-three small planets, and gave his opinion that they could not be grouped together; that there was no apparent connection. "having lost all his teeth, humboldt's articulation was indistinct--he talked very rapidly. his hair was thin and very white, his eyes very blue, his nose too broad and too flat; yet he was a handsome man. he wore a white necktie, a black dress-coat, buttoned up, but not so much so that it hid a figured dark-blue and white waistcoat. he was a little deaf. he told me that he was eighty-nine years old, and that he and bonpland, alone, were living of those who in early life were on expeditions together; that bonpland was eighty-five, and much the more vigorous of the two. "he said that we had gone backwards, morally, in america since he was there,--that then there were strong men there: jefferson, and hamilton, and madison; that the three months he spent in america were spent almost wholly with jefferson. "in the course of conversation he told me that the fifth volume of 'cosmos' was in preparation. he urged me to go to see argelander on my way to london; he followed me out, still urging me to do this, and at the same time assured me that kansas would go all right. "it was singular that humboldt should advise me to use the sextant; it was the first instrument that i ever used, and it is a very difficult one. no young aspirant in science ever left humboldt's presence uncheered, and no petty animosities come out in his record. you never heard of humboldt's complaining that any one had stolen his thunder,--he knew that no one could lift his bolts. "when i came away, he thanked me again for the visit, followed me into the anteroom, and made a low bow." in 1855 mrs. mitchell was taken suddenly ill, and although partial recovery followed, her illness lasted for six years, during which time maria was her constant nurse. for most of the six years her mother's condition was such that merely a general care was needed, but it used to be said that maria's eyes were always upon her. when the opportunity to go to europe came, an older sister came with her family to take maria's place in the home; and when miss mitchell returned she found her mother so nearly in the state in which she had left her, that she felt justified in having taken the journey. mrs. mitchell died in 1861, and a few months after her death mr. mitchell and his daughter removed to lynn, mass.--miss mitchell having purchased a small house in that city, in the rear of which she erected the little observatory brought from nantucket. she was very much depressed by her mother's death, and absorbed herself as much as possible in her observations and in her work for the nautical almanac. soon after her return from europe she had been presented with an equatorial telescope, the gift of american women, through miss elizabeth peabody. the following letter refers to this instrument: letter from admiral smyth. st. john's lodge, near aylesbury, 25-7-'59. my dear miss mitchell: ... we are much pleased to hear of your acquisition of an equatorial instrument under a revolving roof, for it is a true scientific luxury as well as an efficient implement. the aperture of your object-glass is sufficient for doing much useful work, but, if i may hazard an opinion to you, do not attempt too much, for it is quality rather than quantity which is now desirable. i would therefore leave the multiplication of objects to the larger order of telescopes, and to those who are given to sweep and ransack the heavens, of whom there is a goodly corps. now, for your purpose, i would recommend a batch of neat, but not over-close, binary systems, selected so as to have always one or the other on hand. i, however, have been bestirring myself to put amateurs upon a more convenient and, i think, a better mode of examining double stars than by the wire micrometer, with its faults of illumination, fiddling, jumps, and dirty lamps. this is by the beautiful method of rock-crystal prisms, not the rochon method of double-image, but by thin wedges cut to given angles. i have told mr. alvan clark my "experiences." and i hope he will apply his excellent mind to the scheme. i am insisting upon this point in some astronomical twaddle which i am now printing, and of which i shall soon have to request your acceptance of a copy. there is a very important department which calls for a zealous amateur or two, namely, the colors of double stars, for these have usually been noted after the eye has been fatigued with observing in illuminated fields. the volume i hope to forward--_en hommage_--will contain all the pros and cons of this branch. there is, for ultimate utility, nothing like forming a plan and then steadily following it. those who profess they will attend to everything often fall short of the mark. the division of labor leads to beneficial conclusions as well in astronomy as in mechanics and arts. mrs. smyth and my daughter unite with me in wishing you all happiness and success; and believe me my dear miss mitchell, yours very faithfully, w. h. smyth. in regard to the colors of stars, miss mitchell had already begun their study, as these extracts from her diary show: "feb. 19, 1853. i am just learning to notice the different colors of the stars, and already begin to have a new enjoyment. betelgeuse is strikingly red, while rigel is yellow. there is something of the same pleasure in noticing the hues that there is in looking at a collection of precious stones, or at a flower-garden in autumn. blue stars i do not yet see, and but little lilac except through the telescope. "feb. 12, 1855.... i swept around for comets about an hour, and then i amused myself with noticing the varieties of color. i wonder that i have so long been insensible to this charm in the skies, the tints of the different stars are so delicate in their variety. ... what a pity that some of our manufacturers shouldn't be able to steal the secret of dyestuffs from the stars, and astonish the feminine taste by new brilliancy in fashion. [footnote: see chapter xi.] [nantucket], april [1860]. my dear: your father just gave me a great fright by "tapping at my window" (i believe poe's was a door, wasn't it?) and holding up your note. i was busy examining some star notices just received from russia or germany,--i never knew where dorpat is.--and just thinking that my work was as good as theirs. i always noticed that when school-teachers took a holiday in order to visit other institutions they came home and quietly said, "no school is better or as good as mine." and then i read your note, and perceive your reading is as good as mrs. kemble's. now, being _modest_, i always felt afraid the reason i thought you such a good reader was because i didn't know any better, but if all the world is equally ignorant, it makes it all right.... i've been intensely busy. i have been looking for the little inferior planet to cross the sun, which it hasn't done, and i got an article ready for the paper and then hadn't the courage to publish--not for fear of the readers, but for fear that i should change my own ideas by the time 'twas in print. i am hoping, however, to have something by the meeting of the scientific association in august,--some paper,--not to get reputation for myself,--my reputation is so much beyond me that as policy i should keep quiet,--but in order that my telescope may show that it is at work. i am embarrassed by the amount of work it might do--as you do not know which of mrs. browning's poems to read, there are so many beauties. the little republic of san marino presented miss mitchell, in 1859, with a bronze medal of merit, together with the _ribbon_ and _letters patent_ signed by the two captains regent. this medal she prized as highly as the gold one from denmark. "nantucket, may 12, 18[60].... i send you a notice of an occultation; the last sentence and the last figures are mine. you and i can never occult, for have we not always helped one another to shine? do you have worcester's dictionary? i read it continually. did you feast on 'the marble faun'? i have a charming letter from una hawthorne, herself a poet by nature, all about 'papa's book.' ought not mr. hawthorne to be the happiest man alive? he isn't, though! do save all the anecdotes you possibly can, piquant or not; starved people are not over-nice. lynn, jan. 5 [1864]. ... i very rarely see the b----s; they go to a different church, and you know with that class of people "not to be with us is to be against us." indeed, i know very little of lynn people. if i can get at mr. j., when you come to see me i'll ask him to tea. he has called several times, but he's in such demand that he must be engaged some weeks in advance! would you, if you lived in lynn, want to fall into such a mass of idolaters? i was wretchedly busy up to december 31, but have got into quiet seas again. i have had a great deal of company--not a person that i did not want to see, but i can't make the days more than twenty-four hours long, with all my economy of time. this week professor crosby, of salem, comes up with his graduating class and his corps of teachers for an evening. they remained in lynn until miss mitchell was called to vassar college, in 1865, as professor of astronomy and director of the observatory. chapter ix 1865-1885 life at vassar college in her life at vassar college there was a great deal for miss mitchell to get accustomed to; if her duties had been merely as director of the observatory, it would have been simply a continuation of her previous work. but she was expected, of course, to teach astronomy; she was by no means sure that she could succeed as a teacher, and with this new work on hand she could not confine herself to original investigation--that which had been her great aim in life. but she was so much interested in the movement for the higher education of women, an interest which deepened as her work went on, that she gave up, in a great measure, her scientific life, and threw herself heart and soul into this work. for some years after she went to vassar, she still continued the work for the nautical almanac; but after a while she relinquished that, and confined herself wholly to the work in the college. "1866. vassar college brought together a mass of heterogeneous material, out of which it was expected that a harmonious whole would evolve--pupils from all parts of the country, of different habits, different training, different views; teachers, mostly from new england, differing also; professors, largely from massachusetts, yet differing much. and yet, after a year, we can say that there has been no very noisy jarring of the discordant elements; small jostling has been felt, but the president has oiled the rough places, and we have slid over them. "... miss ---is a bigot, but a very sincere one. she is the most conservative person i ever met. i think her a very good woman, a woman of great energy.... she is very kind to me, but had we lived in the colonial days of massachusetts, and had she been a power, she would have burned me at the stake for heresy! "yesterday the rush began. miss lyman [the lady principal] had set the twenty teachers all around in different places, and i was put into the parlor to talk to 'anxious mothers.' "miss lyman had a hoarse cold, but she received about two hundred students, and had all their rooms assigned to them. "while she had one anxious mamma, i took two or three, and kept them waiting until she could attend to them. several teachers were with me. i made a rush at the visitors as they entered, and sometimes i was asked if i were lady principal, and sometimes if i were the matron. this morning miss lyman's voice was gone. she must have seen five hundred people yesterday. "among others there was one miss mitchell, and, of course, that anxious mother put that girl under my special care, and she is very bright. then there were two who were sent with letters to me, and several others whose mothers took to me because they were frightened by miss lyman's _style_. "one lady, who seemed to be a bright woman, got me by the button and held me a long time--she wanted this, that, and the other impracticable thing for the girl, and told me how honest her daughter was; then with a flood of tears she said, 'but she is not a christian. i know i put her into good hands when i put her here.' (then i was strongly tempted to avow my unitarianism.) miss w., who was standing by, said, 'miss lyman will be an excellent spiritual adviser,' and we both looked very serious; when the mother wiped her weeping eyes and said, 'and, miss mitchell, will you ask miss lyman to insist that my daughter shall curl her hair? she looks very graceful when her hair is curled, and i want it insisted upon,' i made a note of it with my pencil, and as i happened to glance at miss w. the corners of her mouth were twitching, upon which i broke down and laughed. the mother bore it very good-naturedly, but went on. she wanted to know who would work some buttonholes in her daughter's dress that was not quite finished, etc., and it all ended in her inviting me to make her a visit. "oct. 31, 1866. our faculty meetings always try me in this respect: we do things that other colleges have done before. we wait and ask for precedent. if the earth had waited for a precedent, it never would have turned on its axis! "sept. 22, 1868. i have written to-day to give up the nautical almanac work. i do not feel sure that it will be for the best, but i am sure that i could not hold the almanac and the college, and father is happy here. "i tell miss lyman that my father is so much pleased with everything here that i am afraid he will be immersed!" [footnote: vassar college, though professedly unsectarian, was mainly under baptist control.] only those who knew vassar college in its earlier days can tell of the life that the father and daughter led there for four years. mr. mitchell died in 1869. [illustration: the father and daughter] "jan. 3, 1868. meeting dr. hill at a private party, i asked him if harvard college would admit girls in fifty years. he said one of the most conservative members of the faculty had said, within sixteen days, that it would come about in twenty years. i asked him if i could go into one of professor peirce's recitations. he said there was nothing to keep me out, and that he would let me know when they came. "at eleven a.m., the next friday, i stood at professor peirce's door. as the professor came in i went towards him, and asked him if i might attend his lecture. he said 'yes.' i said 'can you not say "i shall be happy to have you"?' and he said 'i shall be happy to have you,' but he didn't look happy! "it was with some little embarrassment that mrs. k. and i seated ourselves. sixteen young men came into the room; after the first glance at us there was not another look, and the lecture went on. professor peirce had filled the blackboard with formulae, and went on developing them. he walked backwards and forwards all the time, thinking it out as he went. the students at first all took notes, but gradually they dropped off until perhaps only half continued. when he made simple mistakes they received it in silence; only one, that one his son (a tutor in college), remarked that he was wrong. the steps of his lesson were all easy, but of course it was impossible to tell whence he came or whither he was going.... "the recitation-room was very common-looking--we could not tolerate such at vassar. the forms and benches of the recitation-room were better for taking notes than ours are. "the professor was polite enough to ask us into the senior class, but i had an engagement. i asked him if a young lady presented herself at the door he _could_ keep her out, and he said 'no, and i shouldn't.' i told him i would send some of my girls. "oct. 15, 1868. resolved, in case of my outliving father and being in good health, to give my efforts to the intellectual culture of women, without regard to salary; if possible, connect myself with liberal christian institutions, believing, as i do, that happiness and growth in this life are best promoted by them, and that what is good in this life is good in any life." in august, 1869, miss mitchell, with several of her vassar students, went to burlington, ia., to observe the total eclipse of the sun. she wrote a popular account of her observations, which was printed in "hours at home" for september, 1869. her records were published in professor coffin's report, as she was a member of his party. "sept. 26, 1871. my classes came in to-day for the first time; twenty-five students--more than ever before; fine, splendid-looking girls. i felt almost frightened at the responsibility which came into my hands--of the possible _twist_ which i might give them. "1871. i never look upon the mass of girls going into our dining-room or chapel without feeling their nobility, the sovereignty of their pure spirit." the following letter from miss mitchell, though written at a later date, gives an idea of the practical observing done by her classes: my dear miss ----: i reply to your questions concerning the observatory which you propose to establish. and, first, let me congratulate you that you begin _small_. a large telescope is a great luxury, but it is an enormous expense, and not at all necessary for teaching.... my beginning class uses only a small portable equatorial. it stands out-doors from 7 a.m. to 9 p.m. the girls are encouraged to use it: they are expected to determine the rotation of the sun on its axis by watching the spots--the same for the planet jupiter; they determine the revolution of titan by watching its motions, the retrograde and direct motion of the planets among the stars, the position of the sun with reference to its setting in winter and summer, the phases of venus. all their book learning in astronomy should be mathematical. the astronomy which is not mathematical is what is so ludicrously called "geography of the heavens"--is not astronomy at all. my senior class, generally small, say six, is received as a class, but in practical astronomy each girl is taught separately. i believe in _small_ classes. i instruct them separately, first in the use of the meridian instrument, and next in that of the equatorial. they obtain the time for the college by meridian passage of stars; they use the equatorial just as far as they can do with very insufficient mechanism. we work wholly on planets, and they are taught to find a planet at any hour of the day, to make drawings of what they see, and to determine positions of planets and satellites. with the clock and chronograph they determine difference of right ascension of objects by the electric mode of recording. they make, sometimes, very accurate drawings, and they learn to know the satellites of saturn (titan, rhea, etc.) by their different physiognomy, as they would persons. they have sometimes measured diameters. if you add to your observatory a meridian instrument, i should advise a small one. _size_ is not so important as people generally suppose. nicety and accuracy are what is needed in all scientific work; startling effects by large telescopes and high powers are too suggestive of sensational advertisement. the relation between herself and her pupils was quite remarkable--it was very cordial and intimate; she spoke of them always as her "girls," but at the same time she required their very best work, and was intolerant of shirking, or of an ambition to do what nature never intended the girl in question to do. one of her pupils writes thus: "if it were only possible to tell you of what professor mitchell did for one of her girls! 'her girls!' it meant so much to come into daily contact with such a woman! there is no need of speaking of her ability; the world knows what that was. but as her class-room was unique, having something of home in its belongings, so its atmosphere differed from that of all others. anxiety and nervous strain were left outside of the door. perhaps one clue to her influence may be found in her remark to the senior class in astronomy when '76 entered upon its last year: 'we are women studying together.' "occasionally it happened that work requiring two hours or more to prepare called for little time in the class. then would come one of those treats which she bestowed so freely upon her girls, and which seemed to put them in touch with the great outside world. letters from astronomers in europe or america, or from members of their families, giving delightful glimpses of home life; stories of her travels and of visits to famous people; accounts of scientific conventions and of large gatherings of women,--not so common then as now,--gave her listeners a wider outlook and new interests. "professor mitchell was chairman of a standing committee of the american association for the advancement of women,--that on women's work in science,--and some of her students did their first work for women's organizations in gathering statistics and filling out blanks which she distributed among them. "the benefits derived from my college course were manifold, but time and money would have been well spent had there been no return but that of two years' intercourse with maria mitchell." another pupil, and later her successor at vassar college, miss mary w. whitney, has said of her method of teaching: "as a teacher, miss mitchell's gift was that of stimulus, not that of drill. she could not drill; she would not drive. but no honest student could escape the pressure of her strong will and earnest intent. the marking system she held in contempt, and wished to have nothing to do with it. 'you cannot mark a human mind,' she said, 'because there is no intellectual unit;' and upon taking up her duties as professor she stipulated that she should not be held responsible for a strict application of the system." "july, 1887. my students used to say that my way of teaching was like that of the man who said to his son, 'there are the letters of the english alphabet--go into that corner and learn them.' "it is not exactly my way, but i do think, as a general rule, that teachers talk too much! a book is a very good institution! to read a book, to think it over, and to write out notes is a useful exercise; a book which will not repay some hard thought is not worth publishing. the fashion of lecturing is becoming a rage; the teacher shows herself off, and she does not try enough to develop her pupils. "the greatest object in educating is to give a right habit of study.... * * * * * "... not too much mechanical apparatus--let the imagination have some play; a cube may be shown by a model, but let the drawing upon the blackboard represent the cube; and if possible let nature be the blackboard; spread your triangles upon land and sky. "one of my pupils always threw her triangles on the celestial vault above her head.... "a small apparatus well used will do wonders. a celebrated chemist ordered his servant to bring in the laboratory--on a tray! newton rolled up the cover of a book; he put a small glass at one end, and a large brain at the other--it was enough. * * * * * "when a student asks me, 'what specialty shall i follow?' i answer, 'adopt some one, if none draws you, and wait.' i am confident that she will find the specialty engrossing. "feb. 10, 1887. when i came to vassar, i regretted that mr. vassar did not give full scholarships. by degrees, i learned to think his plan of giving half scholarships better; and to-day i am ready to say, 'give no scholarships at all.' "i find a helping-hand lifts the girl as crutches do; she learns to like the help which is not self-help. "if a girl has the public school, and wants enough to learn, she will learn. it is hard, but she was born to hardness--she cannot dodge it. labor is her inheritance. "i was born, for instance, incapable of appreciating music. i mourn it. should i go to a music-school, therefore? no, avoid the music-school; it is a very expensive branch of study. when the public school has taught reading, writing, and arithmetic, the boy or girl has his or her tools; let them use these tools, and get a few hours for study every day. "... do not give educational aid to sickly young people. the old idea that the feeble young man must be fitted for the ministry, because the more sickly the more saintly, has gone out. health of body is not only an accompaniment of health of mind, but is the cause; the converse may be true,--that health of mind causes health of body; but we all know that intellectual cheer and vivacity act upon the mind. if the gymnastic exercise helps the mind, the concert or the theatre improves the health of the body. "let the unfortunate young woman whose health is delicate take to the culture of the woods and fields, or raise strawberries, and avoid teaching. "better give a young girl who is poor a common-school education, a little lift, and tell her to work out her own career. if she have a distaste to the homely routine of life, leave her the opportunity to try any other career, but let her understand that she stands or falls by herself. "... not every girl should go to college. the over-burdened mother of a large family has a right to be aided by her daughter's hands. i would aid the mother and not the daughter. "i would not put the exceptionally smart girl from a _very_ poor family into college, unless she is a genius; and a genius should wait some years to _prove_ her genius. "endow the already established institution with money. endow the woman who shows genius with _time_. "a case at johns hopkins university is an excellent one. a young woman goes into the institution who is already a scholar; she shows what she can do, and she takes a scholarship; she is not placed in a happy valley of do nothing,--she is put into a workshop, where she can work. "... we are all apt to say, 'could we have had the opportunity in life that our neighbor had,'--and we leave the unfinished sentence to imply that we should have been geniuses. "no one ever says, 'if i had not had such golden opportunities thrust upon me, i might have developed by a struggle'! but why look back at all? why turn your eyes to your shadow, when, by looking upward, you see your rainbow in the same direction? "but our want of opportunity was our opportunity--our privations were our privileges--our needs were stimulants; we are what we are because we had little and wanted much; and it is hard to tell which was the more powerful factor.... * * * * * "small aids to individuals, large aid to masses. * * * * * "the russian czar determined to found an observatory, and the first thing he did was to take a million dollars from the government treasury. he sends to america to order a thirty-five inch telescope from alvan clark,--not to promote science, but to surpass other nations in the size of his glass. 'to him that hath shall be given.' read it, 'to him that hath _should_ be given.' * * * * * "to give wisely is hard. i do not wonder that the millionaire founds a new college--why should he not? millionaires are few, and he is a man by himself--he must have views, or he could not have earned a million. but let the man or woman of ordinary wealth seek out the best institution already started,--the best girl already in college,--and give the endowment. "i knew a rich woman who wished to give aid to some girls' school, and she travelled in order to find that institution which gave the most solid learning with the least show. she found it where few would expect it,--in tennessee. it was worth while to travel. "the aid that comes need not be money; let it be a careful consideration of the object, and an evident interest in the cause. "when you aid a teacher, you improve the education of your children. it is a wonder that teachers work as well as they do. i never look at a group of them without using, mentally, the expression, 'the noble army of martyrs'! "the chemist should have had a laboratory, and the observatory should have had an astronomer; but we are too apt to bestow money where there is no man, and to find a man where there is no money. * * * * * "if every girl who is aided were a very high order of scholar, scholarship would undoubtedly conquer poverty; but a large part of the aided students are ordinary. they lack, at least, executive power, as their ancestors probably did. poverty is a misfortune; misfortunes are often the result of blamable indiscretion, extravagance, etc. "it is one of the many blessings of poverty that one is not obliged to 'give wisely.'" 1866. _to her students:_ "i cannot expect to make astronomers, but i do expect that you will invigorate your minds by the effort at healthy modes of thinking.... when we are chafed and fretted by small cares, a look at the stars will show us the littleness of our own interests. "... but star-gazing is not science. the entrance to astronomy is through mathematics. you must make up your mind to steady and earnest work. you must be content to get on slowly if you only get on thoroughly.... "the phrase 'popular science' has in itself a touch of absurdity. that knowledge which is popular is not scientific. "the laws which govern the motions of the sun, the earth, planets, and other bodies in the universe, cannot be understood and demonstrated without a solid basis of mathematical learning. * * * * * "every formula which expresses a law of nature is a hymn of praise to god. * * * * * "you cannot study anything persistently for years without becoming learned, and although i would not hold reputation up to you as a very high object of ambition, it is a wayside flower which you are sure to have catch at your skirts. "whatever apology other women may have for loose, ill-finished work, or work not finished at all, you will have none. "when you leave vassar college, you leave it the _best educated women in the world_. living a little outside of the college, beyond the reach of the little currents that go up and down the corridors, i think i am a fairer judge of your advantages than you can be yourselves; and when i say you will be the best educated women in the world, i do not mean the education of text-books, and class-rooms, and apparatus, only, but that broader education which you receive unconsciously, that higher teaching which comes to you, all unknown to the givers, from daily association with the noble-souled women who are around you." "1871. when astronomers compare observations made by different persons, they cannot neglect the constitutional peculiarities of the individuals, and there enters into these computations a quantity called 'personal equation.' in common terms, it is that difference between two individuals from which results a difference in the _time_ which they require to receive and note an occurrence. if one sees a star at one instant, and records it, the record of another, of the same thing, is not the same. "it is true, also, that the same individual is not the same at all times; so that between two individuals there is a mean or middle individual, and each individual has a mean or middle self, which is not the man of to-day, nor the man of yesterday, nor the man of to-morrow; but a middle man among these different selves.... * * * * * "we especially need imagination in science. it is not all mathematics, nor all logic, but it is somewhat beauty and poetry. "there will come with the greater love of science greater love to one another. living more nearly to nature is living farther from the world and from its follies, but nearer to the world's people; it is to be of them, with them, and for them, and especially for their improvement. we cannot see how impartially nature gives of her riches to all, without loving all, and helping all; and if we cannot learn through nature's laws the certainty of spiritual truths, we can at least learn to promote spiritual growth while we are together, and live in a trusting hope of a greater growth in the future. "... the great gain would be freedom of thought. women, more than men, are bound by tradition and authority. what the father, the brother, the doctor, and the minister have said has been received undoubtingly. until women throw off this reverence for authority they will not develop. when they do this, when they come to truth through their investigations, when doubt leads them to discovery, the truth which they get will be theirs, and their minds will work on and on unfettered. [1874.] "i am but a woman! "for women there are, undoubtedly, great difficulties in the path, but so much the more to overcome. first, no woman should say, 'i am but a woman!' but a woman! what more can you ask to be? "born a woman--born with the average brain of humanity--born with more than the average heart--if you are mortal, what higher destiny could you have? no matter where you are nor what you are, you are a power--your influence is incalculable; personal influence is always underrated by the person. we are all centres of spheres--we see the portions of the sphere above us, and we see how little we affect it. we forget the part of the sphere around and before us--it extends just as far every way. "another common saying, 'it isn't the way,' etc. who settles the way? is there any one so forgetful of the sovereignty bestowed on her by god that she accepts a leader--one who shall capture her mind? "there is this great danger in student life. now, we rest all upon what socrates said, or what copernicus taught; how can we dispute authority which has come down to us, all established, for ages? "we must at least question it; we cannot accept anything as granted, beyond the first mathematical formulae. question everything else. "'the world is round, and like a ball seems swinging in the air.'[1] [footnote 1: from peter parley's primary geography.] "no such thing! the world is not round, it does not swing, and it doesn't _seem_ to swing! "i know i shall be called heterodox, and that unseen lightning flashes and unheard thunderbolts will be playing around my head, when i say that women will never be profound students in any other department except music while they give four hours a day to the _practice_ of music. i should by all means encourage every woman who is born with musical gifts to study music; but study it as a science and an art, and not as an accomplishment; and to every woman who is not musical, i should say, 'don't study it at all;' you cannot afford four hours a day, out of some years of your life, just to be agreeable in company upon _possible_ occasions. "if for four hours a day you studied, year after year, the science of language, for instance, do you suppose you would not be a linguist? do you put the mere pleasing of some social party, and the reception of a few compliments, against the mental development of four hours a day of study of something for which you were born? "when i see that girls who are required by their parents to go through with the irksome practising really become respectable performers, i wonder what four hours a day at something which they loved, and for which god designed them, would do for them. "i should think that to a real scientist in music there would be something mortifying in this rush of all women into music; as there would be to me if i saw every girl learning the constellations, and then thinking she was an astronomer! "jan. 8, 1876. at the meeting of graduates at the deacon house, the speeches that were made were mainly those of dr. r. and professor b. i am sorry now that i did not at least say that the college is what it is mainly because the early students pushed up the course to a collegiate standard. "jan. 25, 1876. it has become a serious question with me whether it is not my duty to beg money for the observatory, while what i really long for is a quiet life of scientific speculation. i want to sit down and study on the observations made by myself and others." during her later years at vassar, miss mitchell interested herself personally in raising a fund to endow the chair of astronomy. in march, 1886, she wrote: "i have been in new york quite lately, and am quite hopeful that miss ---will do something for vassar. mrs. c., of newburyport, is to ask whittier, who is said to be rich, and ---told me to get anything i could out of her father. but after all i am a poor beggar; my ideas are small!" since miss mitchell's death, the fund has been completed by the alumnae, and is known as the maria mitchell endowment fund. with $10,000 appropriated by the trustees it amounts to $50,000. "june 18, 1876. i had imagined the emperor of brazil to be a dark, swarthy, tall man, of forty-five years; that he would not really have a crown upon his head, but that i should feel it was somewhere around, handy-like, and that i should know i was in royal presence. but he turns out to be a large, old man,--say, sixty-five,--broad-headed and broad-shouldered, with a big white beard, and a very pleasant, even chatty, manner. "once inside of the dome, he seemed to feel at home; to my astonishment he asked if alvan clark made the glass of the equatorial. as he stepped into the meridian-room, and saw the instruments, he said, 'collimators?' i said, 'you have been in observatories before.' 'oh, yes, cambridge and washington,' he replied. he seemed much more interested in the observatory than i could possibly expect. i asked him to go on top of the roof, and he said he had not time; yet he stayed long enough to go up several times. i am told that he follows out, remarkably, his own ideas as to his movements." in 1878, miss mitchell went to denver, colorado, to observe the total eclipse of the sun. she was accompanied by several of her former pupils. she prepared an account of this eclipse, which will be found in chapter xi. "aug. 20, 1878. dr. raymond [president of vassar college] is dead. i cannot quite take it in. i have never known the college without him, and it will make all things different. "personally, i have always been fond of him; he was very enjoyable socially and intellectually. officially he was, in his relations to the students, perfect. he was cautious to a fault, and has probably been very wise in his administration of college affairs. he was broad in his religious views. he was not broad in his ideas of women, and was made to broaden the education of women by the women around him. "june 18, 1881. the dome party to-day was sixty-two in number. it was breakfast, and we opened the dome; we seated forty in the dome and twenty in the meridian-room." this "dome party" requires a few words of explanation, because it was unique among all the vassar festivities. the week before commencement, miss mitchell's pupils would be informed of the approaching gathering by a notice like the following: circular. the annual dome party will be held at the observatory on saturday, the 19th, at 6 p.m. you are cordially invited to be present. m. m. [as this gathering is highly intellectual, you are invited to bring poems.] it was, at first, held in the evening, but during the last years was a breakfast party, its character in other respects remaining the same. little tables were spread under the dome, around the big telescope; the flowers were roses from miss mitchell's own garden. the "poems" were nonsense rhymes, in the writing of which miss mitchell was an adept. each student would have a few verses of a more or less personal character, written by miss mitchell, and there were others written by the girls themselves; some were impromptu; others were set to music, and sung by a selected glee-club. "june 5, 1881. we have written what we call our dome poetry. some nice poems have come in to us. i think the vassar girls, in the main, are magnificent, they are so all-alive.... "may 20, 1882. vassar is getting pretty. i gathered lilies of the valley this morning. the young robins are out in a tree close by us, and the phoebe has built, as usual, under the front steps. "i am rushing dome poetry, but so far show no alarming symptoms of brilliancy." a former student writes as follows about the dome poetry: "at the time it was read, though it seemed mere merry nonsense, it really served a more serious purpose in the work of one who did nothing aimlessly. this apparent nonsense served as the vehicle to convey an expression of approbation, affection, criticism, or disapproval in such a merry mode that even the bitterest draught seemed sweet." "1881, july 5. we left vassar, june 24, on the steamer 'galatea,' from new york to providence. i looked out of my state-room window, and saw a strange-looking body in the northern sky. my heart sank; i knew instantly that it was a comet, and that i must return to the observatory. calling the young people around me, and pointing it out to them, i had their assurance that it was a comet, and nothing but a comet. "we went to bed at nine, and i arose at six in the morning. as soon as i could get my nieces started for providence, i started for stonington,--the most easy of the ways of getting to new york, as i should avoid point judith. "i went to the boat at the stonington wharf about noon, and remained on board until morning--there were few passengers, it was very quiet, and i slept well. "arriving in new york, i took cars at 9 a.m. for poughkeepsie, and reached the college at dinner-time. i went to work the same evening. "as i could not tell at what time the comet would pass the meridian, i stationed myself at the telescope in the meridian-room by 10 p.m., and watched for the comet to cross. as it approached the meridian, i saw that it would go behind a scraggy apple-tree. i sent for the watchman, mr. crumb, to come with a saw, and cut off the upper limbs. he came back with an axe, and chopped away vigorously; but as one limb after another fell, and i said, 'i need more, cut away,' he said, 'i think i must cut down the whole tree.' i said, 'cut it down.' i felt the barbarism of it, but i felt more that a bird might have a nest in it. "i found, when i went to breakfast the next morning, that the story had preceded me, and i was called 'george washington.' "but for all this, i got almost no observation; the fog came up, and i had scarcely anything better than an estimation. i saw the comet blaze out, just on the edge of the field, and i could read its declination only. "on the 28th, 29th, and july 1st, i obtained good meridian passages, and the r.a. must be very good. "jan. 12, 1882. there is a strange sentence in the last paragraph of dr. jacobi's article on the study of medicine by women, to the effect that it would be better for the husband always to be superior to the wife. why? and if so, does not it condemn the ablest women to a single life? "march 13, 1882, 3 p.m. i start for faculty, and we probably shall elect what are called the 'honor girls.' i dread the struggle that is pretty certain to come. each of us has some favorite whom she wishes to put into the highest class, and whom she honestly believes to be of the highest order of merit. i never have the whole ten to suit me, but i can truly say that at this minute i do not care. i should be sorry not to see s., and w., and p., and e., and g., and k. on the list of the ten, but probably that is more than i ought to expect. the whole system is demoralizing and foolish. girls study for prizes, and not for learning, when 'honors' are at the end. the unscholarly motive is wearing. if they studied for sound learning, the cheer which would come with every day's gain would be health-preserving. "... i have seven advanced students, and to-day, when i looked around to see who should be called to help look out for meteors, i could consider only _one_ of them not already overworked, and she was the post-graduate, who took no honors, and never hurried, and has always been an excellent student. "... we are sending home some girls already [november 14], and ---is among them. i am somewhat alarmed at the dropping down, but ---does an enormous amount of work, belongs to every club, and writes for every club and for the 'vassar miscellany,' etc.; of course she has the headache most of the time. "sometimes i am distressed for fear dr. clarke [footnote: author of "sex in education."] is not so far wrong; but i do not think it is the study--it is the morbid conscientiousness of the girls, who think they must work every minute. "april 26, 1882. miss herschel came to the college on the 11th, and stayed three days. she is one of the little girls whom i saw, twenty-three years since, playing on the lawn at sir john herschel's place, collingwood. "... miss herschel was just perfect as a guest; she fitted in beautifully. the teachers gave a reception for her, ---gave her his poem, and henry, the gardener, found out that the man in whose employ he lost a finger was her brother-in-law, in leeds! "jan. 9, 1884. mr. [matthew] arnold has been to the college, and has given his lecture on emerson. the audience was made up of three hundred students, and three hundred guests from town. never was a man listened to with so much attention. whether he is right in his judgment or not, he held his audience by his manly way, his kindly dissection, and his graceful english. socially, he charmed us all. he chatted with every one, he smiled on all. he said he was sorry to leave the college, and that he felt he must come to america again. we have not had such an awakening for years. it was like a new volume of old english poetry. "march 16, 1885. in february, 1831, i counted seconds for father, who observed the annular eclipse at nantucket. i was twelve and a half years old. in 1885, fifty-four years later, i counted seconds for a class of students at vassar; it was the same eclipse, but the sun was only about half-covered. both days were perfectly clear and cold." chapter x 1873 second european tour--russia--frances power cobbe--"the glasgow college for girls" in 1873, miss mitchell spent the summer in europe, and availed herself of this opportunity to visit the government observatory at pulkova, in russia. "eydkuhnen, wednesday, july 30, 1873. certainly, i never in my life expected to spend twenty-four hours in this small town, the frontier town of prussia. here i remembered that our little bags would be examined, and i asked the guard about it, but he said we need not trouble ourselves; we should not be examined until we reached the first russian town of wiersbelow. so, after a mile more of travel, we came to wiersbelow. knowing that we should keep our little compartment until we got to st. petersburg, we had scattered our luggage about; gloves were in one place, veil in another, shawl in another, parasol in another, and books all around. "the train stopped. imagine our consternation! two officials entered the carriage, tall russians in full uniform, and seized everything--shawls, books, gloves, bags; and then, looking around very carefully, espied w's poor little ragged handkerchief, and seized that, too, as a contraband article! we looked at one another, and said nothing. the tall russian said something to us; we looked at each other and sat still. the tall russians looked at one another, and there was almost an official smile between them. "then one turned to me, and said, very distinctly, 'passy-port.' 'oh,' i said, 'the passports are all right; where are they?' and we produced from our pockets the passports prepared at washington, with the official seal, and we delivered them with a sort of air as if we had said, 'you'll find that they do things all right at washington.' "the tall russians got out, and i was about to breathe freely, when they returned, and said something else--not a word did i understand; they exchanged a look of amusement, and w. and i, one of amazement; then one of them made signs to us to get out. the sign was unmistakable, and we got out, and followed them into an immense room, where were tables all around covered with luggage, and about a hundred travellers standing by; and our books, shawls, gloves, etc., were thrown in a heap upon one of these tables, and we awoke to the disagreeable consciousness that we were in a custom-house, and only two out of a hundred travellers, and that we did not understand one word of russian. "but, of course, it could be only a few minutes of delay, and if german and french failed, there is always left the language of signs, and all would be right. "after, perhaps, half an hour, two or three officials approached us, and, holding the passports, began to talk to us. how did they know that those two passports belonged to us? out of two hundred persons, how could they at once see that the woman whose age was given at more than half a century, and the lad whose age was given at less than a score of years, were the two fatigued and weary travellers who stood guarding a small heap of gloves, books, handkerchiefs, and shawls? two of the officials held up the passports to us, pointed to the blank page, shook their heads ominously; the third took the passports, put them into his vest pocket, buttoned up his coat, and motioned to us to follow him. "we followed; he opened the door of an ordinary carriage, waved his hand for us to get in, jumped in himself, and we found we were started back. we could not cross the line between germany and russia. "we meekly asked where we were to go, and were relieved when we found that we went back only to the nearest town, but that the passports must be sent to konigsberg, sixty miles away, to be endorsed by the russian ambassador--it might take some days. w. was very much inclined to refuse to go back and to attempt a war of words, but it did not seem wise to me to undertake a war against the russian government; i know our country does not lightly go into an 'unpleasantness' of that kind.... "so we went back to eydkuhnen,--a little miserable german village. we took rooms at the only hotel, and there we stayed twenty-four hours. before the end of that time, we had visited every shop in the village, and aired our german to most of our fellow-travellers whom we met at the hotel. "the landlord took our part, and declared it was hard enough on simple travellers like ourselves to be stopped in such a way, and that russia was the only country in europe which was rigid in that respect. happily, our passports were back in twenty-four hours, and we started again; our trunks had been registered for st. petersburg, and to st. petersburg they had gone, ahead of us; and of the small heap of things thrown down promiscuously at the custom-house, the whole had not come back to us--it was not very important. i learned how to wear one glove instead of two, or to go without. "we had the ordeal of the custom-house to pass again; but once passed, and told that we were free to go on, it was like going into a clear atmosphere from a fog. we crossed the custom-house threshold into another room, and we found ourselves in russia, and in an excellent, well-furnished, and cheery restaurant. we lost the german smoke and the german beer; we found hot coffee and clean table-cloths. "we did not return to our dusty, red-velvet palace, but we entered a clean, comfortable compartment, with easy sofas, for the night. we started again for st. petersburg; we were now four days from london. i will omit the details of a break-down that night, and another change of cars. we had some sleep, and awoke in the morning to enjoy russia. "and, first, of russian railroads. when the railroads of russia were planned, the emperor nicholas allowed a large sum of money for the building. the engineer showed him his plan. the road wound by slight curves from one town to another. this did not suit the emperor at all. he took his ruler, put it down upon the table, and said: 'i choose to have my roads run so.' of course the engineer assented--he had his large fund granted; a straight road was much cheaper to build than a curved one. as a consequence, he built and furnished an excellent road. "at every 'verst,' which is not quite a mile, a small house is placed at the roadside, on which, in very large figures, the number of versts from st. petersburg is told. the train runs very smoothly and very slowly; twenty miles an hour is about the rate. of course the journey seemed long. for a large part of the way it was an uninhabited, level plain; so green, however, that it seemed like travelling on prairies. occasionally we passed a dreary little village of small huts, and as we neared st. petersburg we passed larger and better built towns, which the dome of some cathedral lighted up for miles. "the road was enlivened, too, by another peculiarity. the restaurants were all adorned by flags of all colors, and festooned by vines. at one place the green arches ran across the road, and we passed under a bower of evergreens. i accepted this, at first, as a russian peculiarity, and was surprised that so much attention was paid to travellers; but i learned that it was not for us at all. the duke of edinboro' had passed over the road a few days before, on his way to st. petersburg, for his betrothal to the only daughter of the czar, and the decorations were for him; and so we felt that we were of the party, although we had not been asked. "we approached st. petersburg just at night, and caught the play of the sunlight on the domes. it is a city of domes--blue domes, green domes, white domes, and, above all, the golden dome of the cathedral of st. isaac's. "it is almost never a single dome. st. isaac's central, gilded dome looms up above its fellow domes, but four smaller ones surround it. "it was summer; the temperature was delightful, about like our october. the showers were frequent, there was no dust and no sultry air. "there must be a great deal of nice mechanical work required in st. petersburg, for on the nevsky perspective, the principal street, there were a great many shops in which graduating and measuring instruments of very nice workmanship were for sale. especially i noticed the excellence of the thermometers, and i naturally stopped to read them. figures are a common language, but it was clear that i was in another planet; i could not read the thermometers! i judged that the weather was warm enough for the thermometer to be at 68. i read, say, 16. and then i remembered that the russians do not put their freezing point at 32, as we do, and i was obliged to go through a troublesome calculation before i could tell how warm it was. "but i came to a still stranger experience. i dated my letters august 3, and went to my banker's, before i sealed them, to see if there were letters for me. the banker's little calendar was hanging by his desk, and the day of the month was on exhibition, in large figures. i read, july 22! this was distressing! was i like alice in wonderland? did time go backward? surely, i had dated august 3. could i be in error twelve days? and then i perceived that twelve days was just the difference of old and new calendars. "how many times i had taught students that the russians still counted their time by the 'old style,' but had never learned it myself! and so i was obliged to teach myself new lessons in science. the earth turns on its axis just the same in russia as in boston, but you don't get out of the sunlight at the boston sunset hour. "when the thermometer stands at 32 in st. petersburg, it does not freeze as it does in boston. on the contrary, it is very warm in st. petersburg, for it means what 104 does in boston. and if you leave london on the 22d of july, and are five days on the way to st. petersburg, a week after you get there it is still the 22d of july! and we complain that the day is too short! "another peculiarity. we strolled over the city all day; we came back to our hotel tired; we took our tea; we talked over the day; we wrote to our friends; we planned for the next day; we were ready to retire. we walked to the window--the sun was striking on all the chimney tops. it doesn't seem to be right even for the lark to go to sleep while the sun shines. we looked at our watches; but the watches said nine o'clock, and we went off to our beds in daytime; and we awoke after the first nap to perceive that the sun still shone into the room. "like all careful aunts, i was unwilling that my nephew should be out alone at night. he was desirous of doing the right thing, but urged that at home, as a little boy, he was always allowed to be out until dark, and he asked if he could stay out until dark! alas for the poor lad! there was no dark at all! i could not consent for him to be out all night, and the twilight was not over. you may read and read that the summer day at st. petersburg is twenty hours long, but until you see that the sun scarcely sets, you cannot take it in. "i wondered whether the laboring man worked eight or ten hours under my window; it seemed to me that he was sawing wood the whole twenty-four! "w. came in one night after a stroll, and described a beautiful square which he had come upon accidentally. i listened with great interest, and said, 'i must go there in the morning; what is the name of it?'--'i don't know,' he replied.--'why didn't you read the sign?' i asked.--'i can't read,' was the reply.--'oh, no; but why didn't you ask some one?'--'i can't speak,' he answered. neither reading nor speaking, we had to learn st. petersburg by our observation, and it is the best way. most travellers read too much. "there are learned institutions in st. petersburg: universities, libraries, picture-galleries, and museums; but the first institution with which i became acquainted was the drosky. the drosky is a very, very small phaeton. it has the driver's seat in front, and a very narrow seat behind him. one person can have room enough on this second seat, but it usually carries two. invariably the drosky is lined with dark-blue cloth, and the drosky-driver wears a dark-blue wrapper, coming to the feet, girded around the waist by a crimson sash. he also wears a bell-shaped hat, turned up at the side. you are a little in doubt, if you see him at first separated from his drosky, whether he is a market-woman or a serving-man, the dress being very much like a morning wrapper. but he is rarely six feet away from his carriage, and usually he is upon it, sound asleep! "the trunks having gone to st. petersburg in advance of ourselves, our first duty was to get possession of them. they were at the custom-house, across the city. my nephew and i jumped upon a drosky--we could not say that we were really _in_ the drosky, for the seat was too short. the drosky-driver started off his horse over the cobble-stones at a terrible rate. i could not keep my seat, and i clung to w. he shouted, 'don't hold by me; i shall be out the next minute!' what could be done? i was sure i shouldn't stay on half a minute. blessings on the red sash of the drosky-man--i caught at that! he drove faster and faster, and i clung tighter and tighter, but alarmed at two immense dangers: first, that i should stop his breath by dragging the girdle so tightly; and, next, that when it became unendurable to him, he would loosen it in front. "i could not perceive that he was aware of my existence at all! he had only one object in life,--to carry us across the city to our place of destination, and to get his copecks in return. "in a few days i learned to like the jolly vehicles very much. they are so numerous that you may pick one up on any street, whenever you are tired of walking. "my principal object in visiting st. petersburg was the astronomical observatory at pulkova, some twelve miles distant. "i had letters to the director, otto von struve, but our consul declared that i must also have one from him, for struve was a very great man. i, of course, accepted it. "we made the journey by rail and coach, but it would be better to drive the whole way. "most observatories are temples of silence, and quiet reigns. as we drove into the grounds at pulkova, a small crowd of children of all ages, and servants of all degrees, came out to meet us. they did not come out to do us honor, but to gaze at us. i could not understand it until i learned that the director of the observatory has a large number of aids, and they, with all their families, live in large houses, connected with the central building by covered ways. "all about the grounds, too, were small observatories,--little temples,--in which young men were practising for observations on the transit of venus. these little buildings, i afterwards learned, were to be taken down and transported, instruments and all, to the coast of asia. "the director of the observatory is otto struve--his father, wilhelm struve, preceded him in this office. properly, the director is herr von struve; but the old russian custom is still in use, and the servants call him wilhelm-vitch; that is, 'the son of william.' "when i bought a photograph of the present emperor, alexander, i saw that he was called nicholas-vitch. "herr struve received us courteously, and an assistant was called to show us the instruments. all observatories are much alike; therefore i will not describe this, except in its peculiarities. one of these was the presence of small, light, portable rooms, i.e., baseless boxes, which rolled over the instruments to protect them; two sides were of wood, and two sides of green silk curtains, which could, of course, be turned aside when the boxes, or little rooms, were rolled over the apparatus. being covered in this way, the heavy shutters can be left open for weeks at a time. "everything was on a large scale--the rooms were immense. "the director has three assistants who are called 'elder astronomers,' and two who are called 'adjunct astronomers.' each of these has a servant devoted to him. i asked one of the elder astronomers if he had rooms in the observatory, and he answered, 'yes, my rooms are 94 ft. by 50.' "they seem to be amused at the size of their lodgings, for mr. struve, when he told me of his apartments, gave me at once the dimensions,--200 ft. by 100 ft. "the room in which we dined with the family of herr struve was immense. i spoke of it, and he said, 'we cannot open our windows in the winter,--the winters are so severe,--and so we must have good air without it.' their drawing-room was also very large; the chairs (innumerable, it seemed to me) stood stiffly around the walls of the room. the floor was painted and highly varnished, and flower-pots were at the numerous windows on little stands. it was scrupulously neat everywhere. "there was very little ceremony at dinner; we had the delicious wild strawberries of the country in great profusion; and the talk, the best part of the dinner, was in german, russian, and english. "madame struve spoke german, russian, and french, and complained that she could not speak english. she said that she had spent three weeks with an english lady, and that she must be very stupid not to speak english. "i noticed that in one of the rooms, which was not so very immense, there was a circular table, a small centre-carpet, and chairs around the table; i have been told that 'in society' in russia, the ladies sit in a circle, and the gentlemen walk around and talk consecutively with the ladies,--kindly giving to each a share of their attention. "they assured me that the winters were charming, the sleighing constant, and the social gatherings cheery; but think of four hours, only, of daylight in the depth of the winter. their dread was the spring and the autumn, when the mud is deep. "everything in the observatory which could be was built of wood. they have the fir, which is very indestructible; it is supposed to show no mark of change in two hundred years. "wood is so susceptible of ornamentation that the pretty villages of russia--and there are some that look like new england villages--struck us very pleasantly, after the stone and brick villages of england. "i try, when i am abroad, to see in what they are superior to us,--not in what they are inferior. "our great idea is, of course, freedom and self-government; probably in that we are ahead of the rest of the world, although we are certainly not so much in advance as we suppose; but we are sufficiently inflated with our own greatness to let that subject take care of itself when we travel. we travel to learn; and i have never been in any country where they did not do something better than we do it, think some thoughts better than we think, catch some inspiration from heights above our own--as in the art of italy, the learning of england, and the philosophy of germany. "let us take the scientific position of russia. when, half a century ago, john quincy adams proposed the establishment of an astronomical observatory, at a cost of $100,000, it was ridiculed by the newspapers, considered utopian, and dismissed from the public mind. when our government, a few years since, voted an appropriation of $50,000 for a telescope for the national observatory, it was considered magnificent. yet, a quarter of a century since (1838), russia founded an astronomical observatory. the government spent $200,000 on instruments, $1,500,000 on buildings, and annually appropriated $38,000 for salaries of observers. i naturally thought that a million and a half dollars, and oriental ideas, combined, would make the observatory a showy place; i expected that the observatory would be surmounted by a gilded dome, and that 'pearly gates' would open as i approached. there is not even a dome! "the central observation-room is a cylinder, and its doors swing back on hinges. wherever it is possible, wood is used, instead of stone or brick. i could not detect, in the whole structure, anything like carving, gilding, or painting, for mere show. it was all for science; and its ornamentations were adapted to its uses, and came at their demand. "in our country, the man of science leads an isolated life. if he has capabilities of administration, our government does not yet believe in them. "the director of the observatory at pulkova has the military rank of general, and he is privy councillor to the czar. every subordinate has also his military position--he is a soldier. "what would you think of it, if the director of any observatory were one of the president's cabinet at washington, in virtue of his position? struve's position is that of a member of the president's cabinet. "here is another difference: ours is a democratic country. we recognize no caste; we are born 'free and equal.' we honor labor; work is ennobling. these expressions we are all accustomed to use. do we live up to them? many a rich man, many a man in fine social position, has married a school-teacher; but i never heard it spoken of as a source of pride in the alliance until i went to despotic russia. struve told me, as he would have told of any other honor which had been his, that his wife, as a girl, had taught school in st. petersburg. and then madame struve joined in the conversation, and told me how much the subject of woman's education still held her interest. "st. petersburg is about the size of philadelphia. struve said, 'there are thousands of women studying science in st. petersburg.' how many thousand women do you suppose are studying science in the whole state of new york? i doubt if there are five hundred. "then again, as to language. it is rare, even among the common people, to meet one who speaks one language only. if you can speak no russian, try your poor french, your poor german, or your good english. you may be sure that the shopkeeper will answer in one or another, and even the drosky-driver picks up a little of some one of them. "of late, the russian government has founded a medical school for women, giving them advantages which are given to men, and the same rank when they graduate; the czar himself contributed largely to the fund. "one wonders, in a country so rich as ours, that so few men and women gratify their tastes by founding scholarships and aids for the tuition of girls--it must be such a pleasant way of spending money. "then as regards religion. i am never in a country where the catholic or greek church is dominant, but i see with admiration the zeal of its followers. i may pity their delusions, but i must admire their devotion. if you look around in one of our churches upon the congregation, five-sixths are women, and in some towns nineteen-twentieths; and if you form a judgment from that fact, you would suppose that religion was entirely a 'woman's right.' in a catholic church or greek church, the men are not only as numerous as the women, but they are as intense in their worship. well-dressed men, with good heads, will prostrate themselves before the image of the holy virgin as many times, and as devoutly, as the beggar-woman. "i think i saw a russian gentleman at st. isaac's touch his forehead to the floor, rise and stand erect, touch the floor again, and rise again, ten times in as many minutes; and we were one day forbidden entrance to a church because the czar was about to say his prayers; we found he was making the pilgrimage of some seventy churches, and praying in each one. "christians who believe in public prayer, and who claim that we should be instant in prayer, would consider it a severe tax upon their energies to pray seventy times a day--they don't care to do it! "then there is the _democracy_ of the church. there are no pews to be sold to the highest bidder--no 'reserved seats;' the oneness and equality before god are always recognized. a russian gentleman, as he prays, does not look around, and move away from the poor beggar next to him. at st. peter's the crowd stands or kneels--at st. isaac's they stand; and they stand literally on the same plane. "i noticed in the crowd at st. isaac's, one festival day, young girls who were having a friendly chat; but their religion was ever in their thoughts, and they crossed themselves certainly once a minute. their religion is not an affair of sunday, but of every day in the week. "the drosky-driver, certainly the most stupid class of my acquaintance in russia, never forgets his prayers; if his passenger is never so much in a hurry, and the bribe never so high, the drosky-driver will check his horse, and make the sign of the cross as he passes the little image of the virgin,--so small, perhaps, that you have not noticed it until you wonder why he slackens his pace. "then as to government. we boast of our national freedom, and we talk about universal suffrage, the 'home of the free,' etc. yet the serfs in russia were freed in march, 1861, just before our civil war began. they freed their serfs without any war, and each serf received some acres of land. they freed twenty-three millions, and we freed four or five millions of blacks; and all of us, who are old enough, remember that one of the fears in freeing the slaves was the number of lawless and ignorant blacks who, it was supposed, would come to the north. "we talk about _universal_ suffrage; a larger part of the antiquated russians vote than of americans. just as i came away from st. petersburg i met a moscow family, travelling. we occupied the same compartment car. it was a family consisting of a lady and her three daughters. when they found where i had been, they asked me, in excellent english, what had carried me to st. petersburg, and then, why i was interested in pulkova; and so i must tell them about american girls, and so, of course, of vassar college. "they plied me with questions: 'do you have women in your faculty? do men and women hold the same rank?' i returned the questions: 'is there a girl's college in moscow?' 'no,' said the youngest sister, with a sigh, 'we are always _going_ to have one.' the eldest sister asked: 'do women vote in america?' 'no,' i said. 'do women vote in russia?' she said 'no;' but her mother interrupted her, and there was a spicy conversation between them, in russian, and then the mother, who had rarely spoken, turned to me, and said: 'i vote, but i do not go to the polls myself. i send somebody to represent me; my vote rests upon my property.' "have you not read a story, of late, in the newspapers, about some excellent women in a little town in connecticut whose pet heifers were taken by force and sold because they refused to pay the large taxes levied upon them by their townsmen, they being the largest holders of property in the town? that circumstance could not have happened in barbarous russia; there, the owner of property has a right to say how it shall be used. "'why do you ask me about our government?' i said to the russian girls. 'are you interested in questions of government?' they replied, 'all russian women are interested in questions of that sort.' how many american women are interested in questions concerning government? "these young girls knew exactly what questions to ask about vassar college,--the course of study, the diploma, the number of graduates, etc. the eldest said: 'we are at once excited when we hear of women studying; we have longed for opportunities to study all our lives. our father was the engineer of the first russian railroad, and he spent two years in america." "i confess to a feeling of mortification when one of these girls asked me, 'did you ever read the translation of a russian book?' and i was obliged to answer 'no.' this girl had read american books in the original. they were talking russian, french, german, and english, and yet mourning over their need of education; and in general education, especially in that of women, i think we must be in advance of them. "one of these sisters, forgetting my ignorance, said something to me in russian. the other laughed. 'what did she say?' i asked. the eldest replied, 'she asked you to take her back with you, and educate her.' 'but,' i said, 'you read and speak your languages--the learning of the world is open to you--found your own college!' and the young girl leaned back on the cushions, drew her mantle around her, and said, 'we have not the energy of the american girl!' "the energy of the american girl! the rich inheritance which has come down to her from men and women who sought, in the new world, a better and higher life. "when the american girl carries her energy into the great questions of humanity, into the practical problems of life; when she takes home to her heart the interests of education, of government, and of religion, what may we not hope for our country! london, 1873. "it was the 26th of august, and i had no hope that miss cobbe could be at her town residence, but i felt bound to deliver mrs. howe's letter, and i wished to give her a vassar pamphlet; so i took a cab and drove; it was at an enormous distance from my lodging--she told me it was six miles. i was as much surprised as delighted when the girl said she was at home, for the house had painters in it, the carpets were up, and everything looked uninhabitable. the girl came back, after taking my card, and asked me if i would go into the studio, and so took me through a pretty garden into a small building of two rooms, the outer one filled with pictures and books. i had never heard that miss cobbe was an artist, and so i looked around, and was afraid that i had got the wrong miss cobbe. but as i glanced at the table i saw the 'contemporary review,' and i took up the first article and read it--by herbert spencer. i had become somewhat interested in a pretty severe criticism of the modes of reasoning of mathematical men, and had perceived that he said the problems of concrete sciences were harder than any of the physical sciences (which i admitted was all true), when a very white dog came bounding in upon me, and i dropped the book, knowing that the dog's mistress must be coming,--and miss cobbe entered. she looked just as i expected, but even larger; but then her head is magnificent because so large. she was very cordial at once, and told me that miss davies had told her i was in london. she said the studio was that of her friend. i could not refrain from thanking her for her books, and telling her how much we valued them in america, and how much good i believed they had done. she colored a very little, and said, 'nothing could be more gratifying to me.' "i had heard that she was not a women's rights woman, and she said, 'who could have told you that? i am remarkably so. i write suffrage articles continually--i sign petitions.' "i was delighted to find that she had been an intimate friend of mrs. somerville; had corresponded with her for years, and had a letter from her after she was ninety-two years of age, when she was reading quaternions for amusement. she said that mrs. somerville would probably have called herself a unitarian, but that really she was a theist, and that it came out more in her later life. she said she was correcting proof of the life by the daughters; that the life was intensely interesting; that mrs. somerville mourned all her life that she had not had the advantages of education. "i asked her how i could get a photograph of mrs. somerville, and she said they could not be bought. she told me, without any hint from me, that she would give vassar college a plaster cast of the bust of mrs. somerville. [footnote: this bust always stood in miss mitchell's parlor at the observatory.] she said, as women grew older, if they lived independent lives, they were pretty sure to be 'women's rights women.' she said the clergy--the broadest, who were in harmony with her--were very courteous, and that since she had grown old (she's about forty-five) all men were more tolerant of her and forgot the difference of sex. "i felt drawn to her when she was most serious. i told her i had suffered much from doubt, and asked her if she had; and she said yes, when she was young; but that she had had, in her life, rare intervals when she believed she held communion with god, and on those rare periods she had rested in the long intermissions. she laughed, and the tears came to her eyes, all together; she was _quick_, and all-alive, and so courteous. when she gave me a book she said, 'may i write your whole name? and may i say "from your friend"?' "then she hurried on her bonnet, and walked to the station with me; and her round face, with the blond hair and the light-blue eyes, seemed to me to become beautiful as she talked. "in edinburgh i asked for a photograph of mary somerville, and the young man behind the counter replied, 'i don't know who it is.' "in london i asked at a bookstore, which the murrays recommended, for a photograph of mrs. somerville and of sir george airy, and the man said if they could be had in london he would get them; and then he asked, 'are they english?' and i informed him that sir george airy was the astronomer royal! * * * * * "'the glasgow college for girls.' seeing a sign of this sort, i rang the door-bell of the house to which it was attached, entered, and was told the lady was at home. as i waited for her, i took up the 'prospectus,' and it was enough,--'music, dancing, drawing, needlework, and english' were the prominent features, and the pupils were children. all well enough,--but why call it a college? "when the lady superintendent came in, i told her that i had supposed it was for more advanced students, and she said, 'oh, it is for girls up to twenty; one supposes a girl is finished by twenty.' "i asked, as modestly as i could, 'have you any pupils in latin and mathematics?' and she said, 'no, it's for girls, you know. dr. m. hopes we shall have some mathematics next year.' 'and,' i asked, 'some latin?' 'yes, dr. m. hopes we shall have some latin; but i confess i believe latin and mathematics all bosh; give them modern languages and accomplishments. i suppose your school is for professional women.' "i told her no; that the daughters of our wealthiest people demand learning; that it would scarcely be considered 'good society' when the women had neither latin nor mathematics. "'oh, well,' she said, 'they get married here so soon.' "when i asked her if they had lady teachers, she said 'oh, no [as if that would ruin the institution]; nothing but first-class masters.' "it was clear that the women taught the needlework." chapter xi papers--science [1874]--the denver eclipse [1878]--colors of stars "the dissemination of information in regard to science and to scientific investigations relieves the scientist from the small annoyances of extreme ignorance. "no one to-day will expect to receive a letter such as reached sir john herschel some years ago, asking for the writer's horoscope to be cast; or such as he received at another time, which asked, shall i marry? and have i seen _her_? "nor can it be long, if the whole population is somewhat educated, that i shall be likely to receive, as i have done, applications for information as to the recovery of stolen goods, or to tell fortunes. "when crossing the atlantic, an irish woman came to me and asked me if i told fortunes; and when i replied in the negative, she asked me if i were not an astronomer. i admitted that i made efforts in that direction. she then asked me what i could tell, if not fortunes. i told her that i could tell when the moon would rise, when the sun would rise, etc. she said, 'oh,' in a tone which plainly said, 'is _that_ all?' "only a few winters since, during a very mild winter, a young lad who was driving a team called out to me on the street, and said he had a question to ask me. "i stopped; and he asked, 'shall we lose our ice-crop this winter?' "it was january, and it was new england. it took very little learning and no alchemy to foretell that the month of february and the neighborhood of boston would give ice enough; and i told him that the ice-crop would be abundant; but i was honest enough to explain to him that my outlook into the future was no better than his. "one of the unfavorable results of the attempt to popularize science is this: the reader of popular scientific books is very likely to think that he understands the science itself, when he merely understands what some writer says about science. "take, for example, the method of determining the distance of the moon from the earth--one of the easiest problems in physical astronomy. the method can be told in a few sentences; yet it took a hundred years to determine it with any degree of accuracy--and a hundred years, not of the average work of mankind in science, but a hundred years during which able minds were bent to the problem. "still, with all the school-masters, and all the teaching, and all the books, the ignorance of the unscientific world is enormous; they are ignorant both ways--they underrate the scientific people and they overrate them. there is, on the one hand, the irish woman who is disappointed because you cannot tell fortunes, and, on the other hand, the cultivated woman who supposes that you must know _all_ science. "i have a friend who wonders that i do not take my astronomical clock to pieces. she supposes that because i am an astronomer, i must be able to be a clock-maker, while i do not handle a tool if i can help it! she did not expect to take her piano to pieces because she was musical! she was as careful not to tinker it as i was not to tinker the clock, which only an expert in clock-making was prepared to handle. "... only a few weeks since i received a letter from a lady who wished to come to make me a visit, and to 'scan the heavens,' as she termed it. now, just as she wrote, the clock, which i was careful not to meddle with, had been rapidly gaining time, and i was standing before it, watching it from hour to hour, and slightly changing its rate by dropping small weights upon its pendulum. time is so important an element with the astronomer, that all else is subordinate to it. "then, too, the uneducated assume the unvarying exactness of mathematical results; while, in reality, mathematical results are often only approximations. we say the sun is 91,000,000 miles from the earth, plus or minus a probable error; that is, we are right, probably, within, say, 100,000 miles; or, the sun is 91,000,000 minus 100,000 miles, or it is 91,000,000 plus 100,000 miles off; and this probable error is only a probability. "if we make one more observation it cannot agree with any one of our determinations, and it changes our probable error. [illustration: bust of maria mitchell. _from original made by miss emma f. brigham in 1877_] "this ignorance of the masses leads to a misconception in two ways; the little that a scientist can do, they do not understand,--they suppose him to be godlike in his capacity, and they do not see results; they overrate him and they underrate him--they underrate his work. "there is no observatory in this land, nor in any land, probably, of which the question is not asked, 'are they doing anything? why don't we hear from them? they should make discoveries, they should publish.' "the one observation made at greenwich on the planet neptune was not published until after a century or more--it was recorded as a star. the observation had to wait a hundred years, about, before the time had come when that evening's work should bear fruit; but it was good, faithful work, and its time came. "kepler was years in passing from one of his laws to another, while the school-boy, to-day, rattles off the three as if they were born of one breath. "the scientist should be free to pursue his investigations. he cannot be a scientist and a school-master. if he pursues his science in all his intervals from his class-work, his classes suffer on account of his engrossments; if he devotes himself to his students, science suffers; and yet we all go on, year after year, trying to work the two fields together, and they need different culture and different implements. "1878. in the eclipse of this year, the dark shadow fell first on the united states thirty-eight degrees west of washington, and moved towards the south-east, a circle of darkness one hundred and sixteen miles in diameter; circle overlapping circle of darkness until it could be mapped down like a belt. "the mapping of the dark shadow, with its limitations of one hundred and sixteen miles, lay across the country from montana, through colorado, northern and eastern texas, and entered the gulf of mexico between galveston and new orleans. this was the region of total eclipse. looking along this dark strip on the map, each astronomer selected his bit of darkness on which to locate the light of science. "but for the distance from the large cities of the country, colorado seemed to be a most favorable part of the shadow; it was little subject to storms, and reputed to be enjoyable in climate and abundant in hospitality. "my party chose denver, col. i had a friend who lived in denver, and she was visiting me. i sought her at once, and with fear and trembling asked, 'have you a bit of land behind your house in denver where i could put up a small telescope?' 'six hundred miles,' was the laconic reply! "i felt that the hospitality of the rocky mountains was at my feet. space and time are so unconnected! for an observation which would last two minutes forty seconds, i was offered six hundred miles, after a journey of thousands. "a journey from boston to denver makes one hopeful for the future of our country. we had hour after hour and day after day of railroad travel, over level, unbroken land on which cattle fed unprotected, summer and winter, and which seemed to implore the traveller to stay and to accept its richness. it must be centuries before the now unpeopled land of western kansas and colorado can be crowded. "we started from boston a party of two; at cincinnati a third joined us; at kansas city we came upon a fourth who was ready to fall into our ranks, and at denver two more awaited us; so we were a party of six--'all good women and true.' "all along the road it had been evident that the country was roused to a knowledge of the coming eclipse; we overheard remarks about it; small telescopes travelled with us, and our landlord at kansas city, when i asked him to take care of a chronometer, said he had taken care of fifty of them in the previous fortnight. our party had three telescopes and one chronometer. "we had travelled so comfortably all along the santa fé road, from kansas city to pueblo, that we had forgotten the possibility of other railroad annoyances than those of heat and dust until we reached pueblo. at pueblo all seemed to change. we left the santa fé road and entered upon that of the rio grande. "which road was to blame, it is not for me to say, but there was trouble at once about our 'round-trip ticket.' that settled, we supposed all was right. "in sending out telescopes so far as from boston to denver, i had carefully taken out the glasses, and packed them in my trunks. i carried the chronometer in my hand. "it was only five hours' travel from pueblo to denver, and we went on to that city. the trunks, for some unexplained reason, or for no reason at all, chose to remain at pueblo. "one telescope-tube reached denver when we did; but a telescope-tube is of no value without glasses. we learned that there was a war between the two railroads which unite at pueblo, and war, no matter where or when it occurs, means ignorance and stupidity. "the unit of measure of value which the railroad man believes in is entirely different from that in which the scientist rests his faith. "a war between two railroads seemed very small compared with two minutes forty seconds of observation of a total eclipse. one was terrestrial, the other cosmic. "it was wednesday when we reached denver. the eclipse was to occur the following monday. "we haunted the telegraph-rooms, and sent imploring messages. we placed ourselves at the station, and watched the trains as they tossed out their freight; we listened to every express-wagon which passed our door without stopping, and just as we were trying to find if a telescope could be hired or bought in denver, the glasses arrived. "it was now friday; we must put up tents and telescopes, and test the glasses. "it rained hard on friday--nothing could be done. it rained harder on saturday. it rained hardest of all on sunday, and hail mingled with the rain. but monday morning was clear and bright. it was strange enough to find that we might camp anywhere around denver. our hostess suggested to us to place ourselves on 'mccullough's addition.' in new york or boston, if i were about to camp on private grounds i should certainly ask permission. in the far west you choose your spot of ground, you dig post-holes and you pitch tents, and you set up telescopes and inhabit the land; and then the owner of the land comes to you, and asks if he may not put up a fence for you, to keep off intruders, and the nearest residents come to you and offer aid of any kind. "our camping-place was near the house occupied by sisters of charity, and the black-robed, sweet-faced women came out to offer us the refreshing cup of tea and the new-made bread. "all that we needed was 'space,' and of that there was plenty. "our tents being up and the telescopes mounted, we had time to look around at the view. the space had the unlimitedness that we usually connect with sea and sky. our tents were on the slope of a hill, at the foot of which we were about six thousand feet above the sea. the plain was three times as high as the hills of the hudson-river region, and there arose on the south, almost from west to east, the peaks upon peaks of the rocky mountains. one needs to live upon such a plateau for weeks, to take in the grandeur of the panorama. "it is always difficult to teach the man of the people that natural phenomena belong as much to him as to scientific people. camping parties who put up telescopes are always supposed to be corporations with particular privileges, and curious lookers-on gather around, and try to enter what they consider a charmed circle. we were remarkably free from specialists of this kind. camping on the south-west slope of the hill, we were hidden on the north and east, and another party which chose the brow of the hill was much more attractive to the crowd. our good serving-man was told to send away the few strollers who approached; even our friends from the city were asked to remove beyond the reach of voice. "there is always some one to be found in every gathering who will not submit to law. at the time of the total eclipse in iowa, in 1869, there passed in and out among our telescopes and observers an unknown, closely veiled woman. the remembrance of that occasion never comes to my mind without the accompaniment of a fluttering green veil. "this time it was a man. how he came among us and why he remained, no one can say. each one supposed that the others knew, and that there was good reason for his presence. if i was under the tent, wiping glasses, he stood beside me; if the photographer wished to make a picture of the party, this man came to the front; and when i asked the servant to send off the half-vagrant boys and girls who stood gazing at us, this man came up and said to me in a confidential tone, 'they do not understand the sacredness of the occasion, and the fineness of the conditions.' there was something regal in his audacity, but he was none the less a tramp. "persons who observe an eclipse of the sun always try to do the impossible. they seem to consider it a solemn duty to see the first contact of sun and moon. the moon, when seen in the daytime, looks like a small faint cloud; as it approaches the sun it becomes wholly unseen; and an observer tries to see when this unseen object touches the glowing disc of the sun. "when we look at any other object than the sun, we stimulate our vision. a good observer will remain in the dark for a short time before he makes a delicate observation on a faint star, and will then throw a cap over his head to keep out strong lights. "when we look at the sun, we at once try to deaden its light. we protect our eyes by dark glasses--the less of sunlight we can get the better. we calculate exactly at what point the moon will touch the sun, and we watch that point only. the exact second by the chronometer when the figure of the moon touches that of the sun, is always noted. it is not only valuable for the determination of longitude, but it is a check on our knowledge of the moon's motions. therefore, we try for the impossible. "one of our party, a young lady from california, was placed at the chronometer. she was to count aloud the seconds, to which the three others were to listen. two others, one a young woman from missouri, who brought with her a fine telescope, and another from ohio, besides myself, stood at the three telescopes. a fourth, from illinois, was stationed to watch general effects, and one special artist, pencil in hand, to sketch views. "absolute silence was imposed upon the whole party a few minutes before each phenomenon. "of course we began full a minute too soon, and the constrained position was irksome enough, for even time is relative, and the minute of suspense is longer than the hour of satisfaction. [footnote: as the computed time for the first contact drew near, the breath of the counter grew short, and the seconds were almost gasped and threatened to become inaudible, when miss mitchell, without moving her eye from the tube of the telescope, took up the counting, and continued until the young lady recovered herself, which she did immediately.] "the moon, so white in the sky, becomes densely black when it is closely ranging with the sun, and it shows itself as a black notch on the burning disc when the eclipse begins. "each observer made her record in silence, and then we turned and faced one another, with record in hand--we differed more than a second; it was a large difference. "between first contact and totality there was more than an hour, and we had little to do but look at the beautiful scenery and watch the slow motion of a few clouds, on a height which was cloud-land to dwellers by the sea. "our photographer begged us to keep our positions while he made a picture of us. the only value to the picture is the record that it preserves of the parallelism of the three telescopes. you would say it was stiff and unnatural, did you not know that it was the ordering of nature herself--they all point to the centre of the solar system. "as totality approached, all again took their positions. the corona, which is the 'glory' seen around the sun, was visible at least thirteen minutes before totality; each of the party took a look at this, and then all was silent, only the count, on and on, of the young woman at the chronometer. when totality came, even that ceased. "how still it was! "as the last rays of sunlight disappeared, the corona burst out all around the sun, so intensely bright near the sun that the eye could scarcely bear it; extending less dazzlingly bright around the sun for the space of about half the sun's diameter, and in some directions sending off streamers for millions of miles. "it was now quick work. each observer at the telescopes gave a furtive glance at the un-sunlike sun, moved the dark eye-piece from the instrument, replaced it by a more powerful white glass, and prepared to see all that could be seen in two minutes forty seconds. they must note the shape of the corona, its color, its seeming substance, and they must look all around the sun for the 'interior planet.' "there was certainly not the beauty of the eclipse of 1869. then immense radiations shot out in all directions, and threw themselves over half the sky. in 1869, the rosy prominences were so many, so brilliant, so fantastic, so weirdly changing, that the eye must follow them; now, scarcely a protuberance of color, only a roseate light around the sun as the totality ended. but if streamers and prominences were absent, the corona itself was a great glory. our special artist, who made the sketch for my party, could not bear the light. "when the two minutes forty seconds were over, each observer left her instrument, turned in silence from the sun, and wrote down brief notes. happily, some one broke through all rules of order, and shouted out, 'the shadow! the shadow!' and looking toward the southeast we saw the black band of shadow moving from us, a hundred and sixty miles over the plain, and toward the indian territory. it was not the flitting of the closer shadow over the hill and dale: it was a picture which the sun threw at our feet of the dignified march of the moon in its orbit. "and now we looked around. what a strange orange light there was in the north-east! what a spectral hue to the whole landscape! was it really the same old earth, and not another planet? "great is the self-denial of those who follow science. they who look through telescopes at the time of a total eclipse are martyrs; they severely deny themselves. the persons who can say that they have seen a total eclipse of the sun are those who rely upon their eyes. my aids, who touched no glasses, had a season of rare enjoyment. they saw mercury, with its gleam of white light, and mars, with its ruddy glow; they saw regulus come out of the darkening blue on one side of the sun, venus shimmer and procyon twinkle near the horizon, and arcturus shine down from the zenith. "_we_ saw the giant shadow as it _left_ us and passed over the lands of the untutored indian; _they_ saw it as it approached from the distant west, as it fell upon the peaks of the mountain-tops, and, in the impressive stillness, moved directly for our camping-ground. "the savage, to whom it is the frowning of the great spirit, is awe-struck and alarmed; the scholar, to whom it is a token of the inviolability of law, is serious and reverent. "there is a dialogue in some of the old school-readers, and perhaps in some of the new, between a tutor and his two pupils who had been out for a walk. one pupil complained that the way was long, the road was dusty, and the scenery uninteresting; the other was full of delight at the beauties he had found in the same walk. one had walked with his eyes intellectually closed; the other had opened his eyes wide to all the charms of nature. in some respects we are all, at different times, like each of these boys: we shut our eyes to the enjoyments of nature, or we open them. but we are capable of improving ourselves, even in the use of our eyes--we see most when we are most determined to see. the _will_ has a wonderful effect upon the perceptive faculties. when we first look up at the myriads of stars seen in a moonless evening, all is confusion to us; we admire their brilliancy, but we scarcely recognize their grouping. we do not feel the need of knowing much about them. "a traveller, lost on a desert plain, feels that the recognition of one star, the pole star, is of itself a great acquisition; and all persons who, like mariners and soldiers, are left much with the companionship of the stars, only learn to know the prominent clusters, even if they do not know the names given to them in books. "the daily wants of the body do not require that we should say "'give me the ways of wandering stars to know the depths of heaven above and earth below.' but we have a hunger of the mind which asks for knowledge of all around us, and the more we gain, the more is our desire; the more we see, the more are we capable of seeing. "besides learning to see, there is another art to be learned,--_not to see_ what is not. "if we read in to-day's paper that a brilliant comet was seen last night in new york, we are very likely to see it to-night in boston; for we take every long, fleecy cloud for a splendid comet. "when the comet of 1680 was expected, a few years ago, to reappear, some young men in cambridge told professor bond that they had seen it; but professor bond did not see it. continually are amateurs in astronomy sending notes of new discoveries to bond, or some other astronomers, which are no discoveries at all! "astronomers have long supposed the existence of a planet inferior to mercury; and m. leverrier has, by mathematical calculation, demonstrated that such a planet exists. he founded his calculations upon the supposed discovery of m. lesbarcault, who declares that it crossed the sun's disc, and that he saw it and made drawings. the internal evidence, from the man's account, is that he was an honest enthusiast. i have no doubt that he followed the path of a solar spot, and as the sun turned on its axis he mistook the motion for that of the dark spot; or perhaps the spot changed and became extinct, and another spot closely resembling it broke out and he was deceived; his wishes all the time being 'father to the thought.' "the eye is as teachable as the hand. every one knows the most prominent constellations,--the pleiades, the great bear, and orion. many persons can draw the figures made by the most brilliant stars in these constellations, and very many young people look for the 'lost pleiad.' but common observers know these stars only as bright objects; they do not perceive that one star differs from another in glory; much less do they perceive that they shine with differently colored rays. "those who know sirius and betel do not at once perceive that one shines with a brilliant white light and the other burns with a glowing red, as different in their brilliancy as the precious stones on a lapidary's table, perhaps for the same reason. and so there is an endless variety of tints of paler colors. "we may turn our gaze as we turn a kaleidoscope, and the changes are infinitely more startling, the combinations infinitely more beautiful; no flower garden presents such a variety and such delicacy of shades. "but beautiful as this variety is, it is difficult to measure it; it has a phantom-like intangibility--we seem not to be able to bring it under the laws of science. "we call the stars garnet and sapphire; but these are, at best, vague terms. our language has not terms enough to signify the different delicate shades; our factories have not the stuff whose hues might make a chromatic scale for them. "in this dilemma, we might make a scale of colors from the stars themselves. we might put at the head of the scale of crimson stars the one known as hind's, which is four degrees west of rigel; we might make a scale of orange stars, beginning with betel as orange red; then we should have betelgeuze, aldebaran, ß ursae minoris, altair and _a_ canis, _a_ lyrae, the list gradually growing paler and paler, until we come to a lyrae, which might be the leader of a host of pale yellow stars, gradually fading off into white. "most of the stars seen with the naked eye are varieties of red, orange, and yellow. the reds, when seen with a glass, reach to violet or dark purple. with a glass, there come out other colors: very decided greens, very delicate blues, browns, grays, and white. if these colors are almost intangible at best, they are rendered more so by the variations of the atmosphere, of the eye, and of the glass. but after these are all accounted for, there is still a real difference. two stars of the class known as double stars, that is, so little separated that considerable optical power is necessary to divide them, show these different tints very nicely in the same field of the telescope. "then there comes in the chance that the colors are complementary; that the eye, fatigued by a brilliant red in the principal star, gives to the companion the color which would make up white light. this happens sometimes; but beyond this the reare innumerable cases of finely contrasted colors which are not complementary, but which show a real difference of light in the stars; resulting, perhaps, from distance,--for some colors travel farther than others, and all colors differ in their order of march,--perhaps from chemical differences. "single blue or green stars are never seen; they are always given as the smaller companion of a pair. "out of several hundred observed by mr. bishop, forty-five have small companions of a bluish, or greenish, or purplish color. almost all of these are stars of the eighth to tenth magnitude; only once are both seen blue, and only in one case is the large one blue. in almost every case the large star is yellow. the color most prevailing is yellow; but the varieties of yellow are very great. "we may assume, then, that the blue stars are faint ones, and probably distant ones. but as not all faint stars or distant ones are blue, it shows that there is a real difference. in the star called 35 piscium, the small star shows a peculiar snuffy-brown tinge. "of two stars in the constellation ursa minoris, not double stars, one is orange and the other is green, both very vivid in color. "from age to age the colors of some prominent stars have certainly changed. this would seem more likely to be from change of place than of physical constitution. "nothing comes out more clearly in astronomical observations than the immense activity of the universe. 'all change, no loss, 'tis revolution all.' "observations of this kind are peculiarly adapted to women. indeed, all astronomical observing seems to be so fitted. the training of a girl fits her for delicate work. the touch of her fingers upon the delicate screws of an astronomical instrument might become wonderfully accurate in results; a woman's eyes are trained to nicety of color. the eye that directs a needle in the delicate meshes of embroidery will equally well bisect a star with the spider web of the micrometer. routine observations, too, dull as they are, are less dull than the endless repetition of the same pattern in crochet-work. "professor chauvenet enumerates among 'accidental errors in observing,' those arising from imperfections in the senses, as 'the imperfection of the eye in measuring small spaces; of the ear, in estimating small intervals of time; of the touch, in the delicate handling of an instrument.' "a girl's eye is trained from early childhood to be keen. the first stitches of the sewing-work of a little child are about as good as those of the mature man. the taking of small stitches, involving minute and equable measurements of space, is a part of every girl's training; she becomes skilled, before she is aware of it, in one of the nicest peculiarities of astronomical observation. "the ear of a child is less trained, except in the case of a musical education; but the touch is a delicate sense given in exquisite degree to a girl, and her training comes in to its aid. she threads a needle almost as soon as she speaks; she touches threads as delicate as the spider-web of a micrometer. "then comes in the girl's habit of patient and quiet work, peculiarly fitted to routine observations. the girl who can stitch from morning to night would find two or three hours in the observatory a relief." chapter xii religious beliefs--comments on sermons--concord school--whittier--cooking schools--anecdotes partly in consequence of her quaker training, and partly from her own indifference towards creeds and sects, miss mitchell was entirely ignorant of the peculiar phrases and customs used by rigid sectarians; so that she was apt to open her eyes in astonishment at some of the remarks and sectarian prejudices which she met after her settlement at vassar college. she was a good learner, however, and after a while knew how to receive in silence that which she did not understand. "miss mitchell," asked one good missionary, "what is your favorite position in prayer?" "flat upon my back!" the answer came, swift as lightning. in 1854 she wrote in her diary: "there is a god, and he is good, i say to myself. i try to increase my trust in this, my only article of creed." miss mitchell never joined any church, but for years before she left nantucket she attended the unitarian church, and her sympathies, as long as she lived, were with that denomination, especially with the more liberally inclined portion. there were always a few of the teachers and' some of the students who sympathized with her in her views; but she usually attended the college services on sunday. president taylor, of vassar college, in his remarks at her funeral, stated that all her life professor mitchell had been seeking the truth,--that she was not willing to accept any statement without studying into the matter herself,--"and," he added, "i think she has found the truth she was seeking." miss mitchell never obtruded her views upon others, nor did she oppose their views. she bore in silence what she could not believe, but always insisted upon the right of private judgment. miss w., a teacher at vassar, was fretting at being obliged to attend chapel exercises twice a day when she needed the time for rest and recreation, and applied to miss mitchell for help in getting away from it. after some talk miss mitchell said: "oh, well, do as _i_ do--sit back folding your arms, and think of something pleasant!" "sunday, dec. 18, 1866. we heard two sermons: the first in the afternoon, by rev. mr. a., baptist, the second in the evening, by rev. mr. b., congregationalist. "rev. mr. a. took a text from deuteronomy, about 'moses;' rev. mr. b. took a text from exodus, about 'moses;' and i am told that the sermon on the preceding sunday was about moses. "it seems to me strange that since we have the history of christ in the new testament, people continue to preach about moses. "rev. mr. a. was a man of about forty years of age. he chanted rather than read a hymn. he chanted a sermon. his description of the journey of moses towards canaan had some interesting points, but his manner was affected; he cried, or pretended to cry, at the pathetic points. i hope he really cried, for a weakness is better than an affectation of weakness. he said, 'the unbeliever is already condemned.' it seems to me that if anything would make me an infidel, it would be the threats lavished against unbelief. "mr. b. is a self-made man, the son of a blacksmith. he brought the anvil, the hammer, and bellows into the pulpit, and he pounded and blew, for he was in earnest. i felt the more respect for him because he was in earnest. but when he snapped his fingers and said, 'i don't care that for the religion of a man which does not begin with prayer,' i was provoked at his forgetfulness of the character of his audience. "1867. i am more and more disgusted with the preaching that i hear!... why cannot a man act himself, be himself, and think for himself? it seems to me that naturalness alone is power; that a borrowed word is weaker than our own weakness, however small we may be. if i reach a girl's heart or head, i know i must reach it through my own, and not from bigger hearts and heads than mine. "march, 1873. there was something so genuine and so sincere in george macdonald that he took those of us who were _emotional_ completely--not by storm so much as by gentle breezes.... what he said wasn't profound except as it reached the depths of the heart.... he gave us such broad theological lessons! in his sermon he said, 'don't trouble yourself about what you _believe_, but _do_ the will of god.' his consciousness of the existence of god and of his immediate supervision was felt every minute by those who listened.... "he stayed several days at the college, and the girls will never get over the good effects of those three days--the cheerier views of life and death. "... rev. dr. peabody preached for us yesterday, and was lovely. everyone was charmed in spite of his old-fashioned ways. his voice is very bad, but it was such a simple, common-sense discourse! mr. vassar said if that was unitarianism, it was just the right thing. "aug. 29, 1875. went to a baptist church, and heard rev. mr. f. 'christ the way, the only way.' the sermon was wholly without logic, and yet he said, near its close, that those who had followed him must be convinced that this was true. he said a traveller whom he met on the cars admitted that we all desired heaven, but believed that there were as many ways to it as to boston. mr. f. said that god had prepared but one way, just as the government in those countries of the old world whose cities were upon almost inaccessible pinnacles had prepared one way of approach. (it occurred to me that if those governments possessed godlike powers, they would have made a great many ways.) "mr. f. was very severe upon those who expect to be saved by their own deserts. he said, 'you tender a farthing, when you owe a million.' i could not see what they owed at all! at this point he might well have given some attention to 'good works;' and if he must mention 'debt,' he might well remind them that they sat in an unpaid-for church! "it was plain that he relied upon his anecdotes for the hold upon his audience, and the anecdotes were attached to the main discourse by a very slender thread of connection. i felt really sad to know that not a listener would lead a better life for that sermon--no man or woman went out cheered, or comforted, or stimulated. "on the whole, it is strange that people who go to church are no worse than they are! "sept. 26, 1880. a clergyman said, in his sermon, 'i do not say with the frenchman, if there were no god it would be well to invent one, but i say, if there were no future state of rewards and punishments, it would be better to believe in one.' did he mean to say, 'better to believe a lie'? "march 27, 1881. dr. lyman abbott preached. i was surprised to find how liberal congregational preaching had become, for he said he hoped and expected to see women at the bar and in the pulpit, although he believed they would always be exceptional cases. he preached mainly on the motherhood of god, and his whole sermon was a tribute to womanhood.... i rejoice at the ideal womanhood of purity which he put before the girls. i wish some one would preach purity to young men. "july 1, 1883. i went to hear rev. mr. ---at the universalist church. he enumerated some of the dangers that threaten us: one was 'the doctrines of scientists,' and he named tyndale, huxley, and spencer. i was most surprised at his fear of these men. can the study of truth do harm? does not every true scientist seek only to know the truth? and in our deep ignorance of what is truth, shall we dread the search for it? "i hold the simple student of nature in holy reverence; and while there live sensualists, despots, and men who are wholly self-seeking, i cannot bear to have these sincere workers held up in the least degree to reproach. and let us have truth, even if the truth be the awful denial of the good god. we must face the light and not bury our heads in the earth. i am hopeful that scientific investigation, pushed on and on, will reveal new ways in which god works, and bring to us deeper revelations of the wholly unknown. "the physical and the spiritual seem to be, at present, separated by an impassable gulf; but at any moment that gulf may be overleaped--possibly a new revelation may come.... "april, 1878. i called on professor henry at the smithsonian institute. he must be in his eightieth year; he has been ill and seems feeble, but he is still the majestic old man, unbent in figure and undimmed in eye. "i always remember, when i see him, the remark of dorothy dix, 'he is the truest man that ever lived.' "we were left alone for a little while, and he introduced the subject of his nearness to death. he said, 'the national academy has raised $40,000, the interest of which is for myself and family as long as any of us live [he has daughters only], and in view of my death it is a great comfort to me.' i ventured to ask him if he feared death at all. he said, 'not in the least; i have thought of it a great deal, and have come to feel it a friend. i _cherish_ the belief in immortality; i have suffered much, at times, in regard to that matter.' scientifically considered, only, he thought the probability was on the side of continued existence, as we must believe that spirit existed independent of matter. "he went to a desk and pulled out from a drawer an old copy of 'gregory's astronomy,' and said, 'that book changed my whole life--i read it when i was sixteen years old; i had read, previously, works of the imagination only, and at sixteen, being ill in bed, that book was near me; i read it, and determined to study science.' i asked him if a life of science was a good life, and he said that he felt that it was so. "... when i was travelling with miss s., who was near-sighted and kept her eyes constantly half-shut, it seemed to me that every other young lady i met had wide, staring eyes. now, after two years sitting by a person who never reasons, it strikes me that every other person whom i meet has been thinking hard, and his logic stands out a prominent characteristic. "aug. 27, 1879. scientific association met at saratoga. ... professor peirce, now over seventy years old, was much the same as ever. he went on in the cars with us, and was reading mallock's 'is life worth living?' and i asked, 'is it?' to which professor peirce replied, 'yes, i think it is.' then i asked, 'if there is no future state, is life worth living?' he replied, 'indeed it is not; life is a cruel tragedy if there is no immortality.' i asked him if he conceived of the future life as one of embodiment, and he said 'yes; i believe with st paul that there is a spiritual body....' "professor peirce's paper was on the 'heat of the sun;' he considers the sun fed not by impact of meteors, but by the compression of meteors. i did not think it very sound. he said some good things: 'where the truth demands, accept; what the truth denies, reject.' "concord, mass., 1879. to establish a school of philosophy had been the dream of alcott's life; and there he sat as i entered the vestry of a church on one of the hottest days in august. he looked full as young as he did twenty years ago, when he gave us a 'conversation' in lynn. elizabeth peabody came into the room, and walked up to the seat of the rulers; her white hair streamed over her shoulders in wild carelessness, and she was as careless as ever about her whole attire, but it was beautiful to see the attention shown to her by mr. alcott and mr. sanborn. "emerson entered,--pale, thin, almost ethereal in countenance,--followed by his daughter, who sat beside him and watched every word that he uttered. on the whole, it was the same emerson--he stumbled at a quotation as he always did; but his thoughts were such as only emerson could have thought, and the sentences had the emersonian pithiness. he made his frequent sentences very emphatic. it was impossible to see any thread of connection; but it always was so--the oracular sentences made the charm. the subject was memory.' he said, 'we remember the selfishness or the wrong act that we have committed for years. it is as it should be--memory is the police-officer of the universe.' 'architects say that the arch never rests, and so the past never rests.' (was it, never sleeps?) 'when i talk with my friend who is a genealogist, i feel that i am talking with a ghost.' "the little vestry, fitted perhaps for a hundred people, was packed with two hundred,--all people of an intellectual cast of face,--and the attention was intense. the thermometer was ninety in the shade! "i did not speak to mr. emerson; i felt that i must not give him a bit of extra fatigue. "july 12, 1880. the school of philosophy has built a shanty for its meetings, but it is a shanty to be proud of, for it is exactly adapted to its needs. it is a long but not low building, entirely without finish, but water-tight. a porch for entrance, and a recess similar at the opposite end, which makes the place for the speakers. there was a small table upon the platform on which were pond lilies, some shelves around, and a few busts--one of socrates, i think. "i went in the evening to hear dr. harris on 'philosophy.' the rain began to come down soon after i entered, and my philosophy was not sufficient to keep me from the knowledge that i had neither overshoes nor umbrella; i remembered, too, that it was but a narrow foot-path through the wet grass to the omnibus. but i listened to dr. harris, and enjoyed it. he lauded fichte as the most accurate philosopher following kant--he said not of the greatest _breadth_, but the most acute. "after dr. harris' address, mr. alcott made a few remarks that were excellent, and said that when we had studied philosophy for fifteen years, as the lecturer had done, we might know something; but as it was, he had pulled us to pieces and then put us together again. "the audience numbered sixty persons. "may, 1880. i have just finished miss peabody's account of channing. i have been more interested in miss peabody than in channing, and have felt how valuable she must have been to him. how many of channing's sermons were instigated by her questions! ... miss peabody must have been very remarkable as a young woman to ask the questions which she asked at twenty. "april, 1881. the waste of flowers on easter sunday distressed me. something is due to the flowers themselves. they are massed together like a bushel of corn, and look like red and white sugar-plums as seen in a confectioner's window. "a pillow of flowers is a monstrosity. a calla lily in a vase is a beautiful creation; so is a single rose. but when the rose is crushed by a pink on each side of it, and daisies crush the pinks, and azaleas surround the daisies, there is no beauty and no fitness. "the cathedral had no flowers. "aug. 22, 1882. we visited whittier; we found him at lunch, but he soon came into the parlor. he was very chatty, and seemed glad to see us. mrs. l. was with me, and whittier was very ready to write in the album which she brought with her, belonging to her adopted son. we drifted upon theological subjects, and i asked mr. whittier if he thought that we fell from a state of innocence; he replied that he thought we were better than adam and eve, and if they fell, they 'fell up.' "his faith seems to be unbounded in the goodness of god, and his belief in moral accountability. he said, 'i am a good deal of a quaker in my conviction that a light comes to me to dictate to me what is right.' we stayed about an hour, and we were afraid it would be too much for him; but miss johnson, his cousin, who lives with him, assured us that it was good for him; and he himself said that he was sorry to have us go. "one thing that he said, i noted: that his fancy was for farm-work, but he was not strong enough; he had as a young man some literary ambition, but never thought of attaining the reputation which had come to him. "july 31, 1883. i have had two or three rich days! on friday last i went to holderness, n.h., to the asquam house; i had been asked by mrs. t. to join her party. there were at this house mr. whittier, mr. and mrs. cartland, professor and mrs. johnson, of yale, mr. williams, the chinese scholar, his brother, an episcopal clergyman, and several others. the house seemed full of fine, cultivated people. we stayed two days and a half. "and first of the scenery. the road up to the house is a steep hill, and at the foot of the hill it winds and turns around two lakes. the panorama is complete one hundred and eighty degrees. beyond the lakes lie the mountains. we do not see mt. washington. the house has a piazza nearly all around it. we had a room on the first floor--large, and with two windows opening to the floor. "the programme of the day's work was delightfully monotonous. for an hour or so after breakfast we sat in the ladies' parlor, we sewed, and we told anecdotes. whittier talked beautifully, almost always on the future state and his confidence in it. occasionally he touched upon persons. he seems to have loved lydia maria child greatly. "when the cool of the morning was over, we went out upon the piazza, and later on we went under the trees, where, it is said, whittier spends most of the time. "there was little of the old-time theology in his views; his faith has been always very firm. mr. cartland asked me one day if i really felt there was any doubt of the immortality of the soul. i told him that on the whole i believed it more than i doubted it, but i could not say that i felt no doubt. whittier asked me if there were no immortality if i should be distressed by it, and i told him that i should be exceedingly distressed; that it was the only thing that i craved. he said that 'annihilation was better for the wicked than everlasting punishment,' and to that i assented. he said that he thought there might be persons so depraved as not to be worth saving. i asked him if god made such. nobody seemed ready to reply. besides myself there was another of the party to whom a dying friend had promised to return, if possible, but had not come. "whittier believed that they did sometimes come. he said that of all whom he had lost, no one would be so welcome to him as lydia maria child. "we held a little service in the parlor of the hotel, and mrs. c. read the fourteenth chapter of john. rev. mr. w. read a sermon from 'the pure in heart shall see god," written by parkhurst, of new york. he thought the child should be told that in heaven he should have his hobby-horse. after the service, when we talked it over, i objected to telling the child this. whittier did not object; he said that luther told his little boy that he should have a little dog with a golden tail in heaven. "aug. 26, 1886. i have been to see an exhibition of a cooking school. i found sixteen girls in the basement of a school-house. they had long tables, across which stretched a line of gas-stoves and jets of gas. some of the girls were using saucepans; they set them upon the stove, and then sat down where they could see a clock while the boiling process went on. "at one table a girl was cutting out doughnuts; at another a girl was making a pudding--a layer of bits of bread followed by a layer of fruit. each girl had her rolling-pin, and moulding-board or saucepan. "the chief peculiarity of these processes was the cleanliness. the rolling-pins were clean, the knives were clean, the aprons were clean, the hands were clean. not a drop was spilled, not a crumb was dropped. "if into the kitchen of the crowded mother there could come the utensils, the commodities, the clean towels, the ample _time_, there would come, without the lessons, a touch of the millennium. "i am always afraid of manual-labor schools. i am not afraid that these girls could not read, for every american girl reads, and to read is much more important than to cook; but i _am_ afraid that not all can _write_--some of them were not more than twelve years old. "and what of the boys? must a common cook always be a girl? and must a boy not cook unless on the top of the ladder, with the pay of the president of harvard college? "i am jealous for the schools; i have heard a gentleman who stands high in science declare that the cooking schools would eventually kill out every literary college in the land--for women. but why not for men? if the food for the body is more important than the food for the mind, let us destroy the latter and accept the former, but let us not continue to do what has been tried for fifteen hundred years,--to keep one half of the world to the starvation of the mind, in order to feed better the physical condition of the other half. "let us have cooks; but let us leave it a matter of choice, as we leave the dressmaking and the shoe-making, the millinery and the carpentry,--free to be chosen! "there are cultivated and educated women who enjoy cooking; so there are cultivated men who enjoy kensington embroidery. who objects? but take care that some rousing of the intellect comes first,--that it may be an enlightened choice,--and do not so fill the day with bread and butter and stitches that no time is left for the appreciation of whittier, letting at least the simple songs of daily life and the influence of rhythm beautify the dreary round of the three meals a day." miss mitchell had a stock of conundrums on hand, and was a good guesser. she told her stories at all times when they happened to come into her mind. she would arrive at her sister's house, just from poughkeepsie on a vacation, and after the threshold was crossed and she had said "good morning," in a clear voice to be heard by all within her sight, she would, perhaps, say, "well, i have a capital story which i must tell before i take my bonnet off, or i shall forget it!" and there went with her telling an action, voice, and manner which added greater point to the story, but which cannot be described. one of her associates at vassar, in recalling some of her anecdotes, writes: "professor mitchell was quite likely to stand and deliver herself of a bright little speech before taking her seat at breakfast. it was as though the short walk from the observatory had been an inspiration to thought." she was quick at repartee. on one occasion charlotte cushman and her friend miss stebbins were visiting miss mitchell at vassar. miss mitchell took them out for a drive, and pointed out the different objects of interest as they drove along the banks of the hudson. "what is that fine building on the hill?" asked miss cushman.--"that," said miss mitchell, "was a boys' school, originally, but it is now used as a hotel, where they charge five dollars a day!"--"five dollars a day?" exclaimed miss cushman; "jupiter ammon!"--"no," said miss stebbins, "jupiter mammon!"--"not at all," said miss mitchell, "jupiter _gammon!_" "farewell, maria," said an old friend, "i hope the lord will be with thee." "good-by," she replied, "i _know_ he will be with you." a characteristic trait in miss mitchell was her aversion to receiving unsolicited advice in regard to her private affairs. "a suggestion is an impertinence," she would often say. the following anecdote shows how she received such counsel: a literary man of more than national reputation said to one of her admirers, "i, for one, cannot endure your maria mitchell." at her solicitation he explained why; and his reason was, as she had anticipated, founded on personal pique. it seems he had gone up from new york to poughkeepsie especially to call upon professor mitchell. during the course of conversation, with that patronizing condescension which some self-important men extend to all women indiscriminately, he proceeded to inform her that her manner of living was not in accordance with his ideas of expediency. "now," he said, "instead of going for each one of your meals all the way from your living-rooms in the observatory over to the dining-hall in the college building, i should think it would be far more convenient and sensible for you to get your breakfast, at least, right in your own apartments. in the morning you could make a cup of coffee and boil an egg with almost no trouble." at which professor mitchell drew herself up with the air of a tragic queen, saying, "and is my time worth no more than to boil eggs?" chapter xiii miss mitchell's letters--woman suffrage--membership in various societies--published articles--death--conclusion miss mitchell was a voluminous letter writer and an excellent correspondent, but her letters are not essays, and not at all in the approved style of the "complete letter writer." if she had any particular thing to communicate, she rushed into the subject in the first line. in writing to her own family and intimate friends, she rarely signed her full name; sometimes she left it out altogether, but ordinarily "m.m." was appended abruptly when she had expressed all that she had to say. she wrote as she talked, with directness and promptness. no one, in watching her while she was writing a letter, ever saw her pause to think what she should say next or how she should express the thought. when she came to that point, the "m.m." was instantly added. she had no secretiveness, and in looking over her letters it has been almost impossible to find one which did not contain too much that was personal, either about herself or others, to make it proper; especially as she herself would be very unwilling to make the affairs of others public. "oct. 22, 1860. i have spent $100 on dress this year. i have a very pretty new felt bonnet of the fashionable shape, trimmed with velvet; it cost only $7, which, of course, was pitifully cheap for broadway. if thou thinks after $100 it wouldn't be extravagant for me to have a waterproof cloak and a linsey-woolsey morning dress, please to send me patterns of the latter material and a description of waterproofs of various prices. they are so ugly, and i am so ditto, that i feel if a few dollars, more or less, would make me look better, even in a storm, i must not mind it." "my orthodoxy is settled beyond dispute, i trust, by the following circumstance: the editor of a new york magazine has written to me to furnish an article for the christmas number on 'the star in the east.' i have ventured, in my note of declination, to mention that if i investigated that subject i might decide that there was no star in the case, and then what would become of me, and _where should i go_? since that he has not written, so i may have hung myself! "1879. april 25. i have 'done' new york very much as we did it thirty years ago. on saturday i went to miss booth's reception, and it was like miss lynch's, only larger than miss lynch's was when i was there.... miss booth and a friend live on fifty-ninth street, and have lived together for years. miss booth is a nice-looking woman. she says she has often been told that she looked like me; she has gray hair and black eyes, but is fair and well-cut in feature. i had a very nice time. "on sunday i went to hear frothingham, and he was at his very best. the subject was 'aspirations of man,' and the sermon was rich in thought and in word. ... frothingham's discourse was more cheery than usual; he talked about the wonderful idea of personal immortality, and he said if it be a dream of the imagination let us worship the imagination. he spoke of mrs. child's book on 'aspirations,' and i shall order it at once. the only satire was such a sentence as this: on speaking of a piece of egyptian sculpture he said, 'the gates of heaven opened to the good, not to the orthodox.' "to-day, monday, i have been to a public school (a primary) and to stewart's mansion. i asked the majordomo to take us through the rooms on the lower floor, which he did. i know of no palace which comes up to it. the palaces always have a look as if at some point they needed refurbishing up. i suppose that mrs. stewart uses that dining-room, but it did not look as if it was made to eat in. i still like gérôme's 'chariot race' better than anything else of his. the 'horse fair' was too high up for me to enjoy it, and a little too mixed up. "1873. st. petersburg is another planet, and, strange to say, is an agreeable planet. some of these europeans are far ahead of us in many things. i think we are in advance only in one universal democracy of freedom. but then, that is everything. "nov. 17, 1875. i think you are right to decide to make your home pleasant at any sacrifice which involves _only_ silence. and you are so all over a radical, that it won't hurt you to be toned down a little, and in a few years, as the world moves, your family will have moved one way and you the other a little, and you will suddenly find yourself on the same plane. it is much the way that has been between miss ---and myself. to-day she is more of a women's rights woman than i was when i first knew her, while i begin to think that the girls would better dress at tea-time, though i think on that subject we thought alike at first, so i'll take another example. "i have learned to think that a _young_ girl would better not walk to town alone, even in the daytime. when i came to vassar i should have allowed a child to do it. but i never knew _much_ of the world--never shall--nor will you. and as we were both born a little deficient in worldly caution and worldly policy, let us receive from others those, lessons,--_do as well as we can_, and keep our _heart_ unworldly if our manners take on something of those ways. "oct. 25, 1875.... i have scarcely got over the _tire_ of the congress [footnote: the annual meeting of the association for the advancement of women, of which miss mitchell was president. it was held at syracuse, n.y., in 1875.] yet, although it is a week since i returned. i feel as if a great burden was lifted from my soul. you will see my 'speech' in the 'woman's journal,' but in the last sentence it should be 'eastward' and not '_earth_ward.' it was a grand affair, and babies came in arms. school-boys stood close to the platform, and school-girls came, books in hand. the hall was a beautiful opera-house, and could hold at least one thousand seven hundred. it was packed and jammed, and rough men stood in the aisles. when i had to speak to announce a paper i stood _very still_ until they became quiet. once, as i stood in that way, a man at the extreme rear, before i had spoken a word, shouted out, 'louder!' we all burst into a laugh. then, of course, i had to make them quiet again. i lifted the little mallet, but i did not strike it, and they all became still. i was surprised at the good breeding of such a crowd. in the evening about half was made up of men. i could not have believed that such a crowd would keep still when i asked them to. "they say i did well. think of my developing as a president of a social science society in my old age!" miss mitchell took no prominent part in the woman suffrage movement, but she believed in it firmly, and its leaders were some of her most highly valued friends. "sept. 7, 1875. went to a picnic for woman suffrage at a beautiful grove at medfield, mass. it was a gathering of about seventy-five persons (mostly from needham), whose president seemed to be vigorous and good-spirited. "the main purpose of the meeting was to try to affect public sentiment to such an extent as to lead to the defeat of a man who, when the subject of woman suffrage was before the legislature, said that the women had all they wanted now--that they could get anything with 'their eyes as bright as the buttons on an angel's coat.' lucy stone, mr. blackwell, rev. mr. bush, miss eastman, and william lloyd garrison spoke. "garrison did not look a day older than when i first saw him, forty years ago; he spoke well--they said with less fire than he used in his younger days. garrison said what every one says--that the struggle for women was the old anti-slavery struggle over again; that as he looked around at the audience beneath the trees, it seemed to be the same scene that he had known before. "... we had a very good bit of missionary work done at our table (at vassar) to-day. a man whom we all despise began to talk against voting by women. i felt almost inclined to pay him something for his remarks. "a group from the washington women suffrage association stopped here to-day.... i liked susan b. anthony very much. she seemed much worn, but was all alive. she is eighteen months younger than i, but seems much more alert. i suppose brickbats are livelier than logarithms!" miss mitchell was a member of several learned societies. she was the first woman elected to membership of the american academy of arts and sciences, whose headquarters are at boston. in 1869 she was chosen a member of the american philosophical society, a society founded by benjamin franklin, in philadelphia. the american association for the advancement of science made her a member in the early part of its existence. miss mitchell was one of the earliest members of the american association for the advancement of women. at one period she was president of the association, and for many years served as chairman of the committee on science. in this latter capacity she reached, through circulars and letters, women studying science in all parts of the country; and the reports, as shown from year to year, show a wonderful increase in the number of such women. she was a member, also, of the new england women's club, of boston, and after her annual visit at christmas she entertained her students at vassar with descriptions of the receptions and meeting of that body. she was also a member of the new york sorosis. she received the degree of ph.d. from rutgers female college in 1870, her first degree of ll.d. from hanover college in 1832, and her last ll.d. from columbia college in 1887. miss mitchell had no ambition to appear in print, and most of her published articles were in response to applications from publishers. a paper entitled "mary somerville" appeared in the "atlantic monthly" for may, 1860. there were several articles in "silliman's journal,"--mostly results of observations on jupiter and saturn,--a few popular science papers in "hours at home," and one on the "herschels," printed in "the century" just after her death. miss mitchell also read a few lectures to small societies, and to one or two girls' schools; but she never allowed such outside work to interfere with her duties at vassar college, to which she devoted herself heart and soul. when the failure of her health became apparent to the members of her family, it was with the utmost difficulty that miss mitchell could be prevailed upon to resign her position. she had fondly hoped to remain at vassar until she should be seventy years old, of which she lacked about six months. it was hoped that complete rest might lead to several years more of happy life for her; but it was not to be so--she died in lynn, june 28, 1889. it was one of miss mitchell's boasts that she had earned a salary for over fifty years, without any intermission. she also boasted that in july, 1883, when she slipped and fell, spraining herself so that she was obliged to remain in the house a day or two, it was the first time in her memory when she had remained in the house a day. in fact, she made a point of walking out every day, no matter what the weather might be. a serious fall, during her illness in lynn, stopped forever her daily walks. she had resigned her position in january, 1888. the resignation was laid on the table until the following june, at which time the trustees made her professor emeritus, and offered her a home for life at the observatory. this offer she did not accept, preferring to live with her family in lynn. the following extracts from letters which she received at this time show with what reverence and love she was regarded by faculty and students. "jan. 9, 1888.... you may be sure that we shall be glad to do all we can to honor one whose faithful service and honesty of heart and life have been among the chief inspirations of vassar college throughout its history. of public reputation you have doubtless had enough, but i am sure you cannot have too much of the affection and esteem which we feel toward you, who have had the privilege of working, with you." "jan. 10, 1888. you will consent, you _must_ consent, to having your home here, and letting the work go. it is not astronomy that is wanted and needed, it is maria mitchell.... the richest part of my life here is connected with you.... i cannot picture vassar without you. there's nothing to point to!" "may 5, 1889. in all the great wonder of life, you have given me more of what i have wanted than any other creature ever gave me. i hoped i should amount to something for your sake." dr. eliza m. mosher, at one time resident physician at the college, said of her: "she was quick to withdraw objections when she was convinced of error in her judgment. i well remember her opposition to the ground i took in my 'maiden speech' in faculty meeting, and how, at supper, she stood, before sitting down, to say, 'you were right this afternoon. i have thought the matter over, and, while i do not like to believe it, i think it is true.'" of her rooms at the observatory, miss grace anna lewis, who had been a guest, wrote thus: "her furniture was plain and simple, and there was a frank simplicity corresponding therewith which made me believe she chose to have it so. it looked natural for her. i think i should have been disappointed had i found her rooms fitted up with undue elegance." "professor mitchell's position at vassar gave astronomy a prominence there that it has never had in any other college for women, and in but few for men. i suppose it would have made no difference what she had taught. doubtless she never suspected how many students endured the mathematical work of junior astronomy in order to be within range of her magnetic personality." (from "wide awake," september, 1889.) a graduate writes: "her personality was so strong that it was felt all over the college, even by those who were not in her department, and who only admired her from a distance." extract from a letter written after her death by a former pupil: "i count maria mitchell's services to vassar and her pupils infinitely valuable, and her character and attainments great beyond anything that has yet been told.... i was one of the pupils upon whom her freedom from all the shams and self-deceptions made an impression that elevated my whole standard, mental and moral.... the influence of her own personal character sustains its supreme test in the evidence constantly accumulating, that it strengthens rather than weakens with the lapse of time. her influence upon her pupils who were her daily companions has been permanent, character-moulding, and unceasingly progressive." president taylor, in his address at her funeral, said: "if i were to select for comment the one most striking trait of her character, i should name her _genuineness_. there was no false note in maria mitchell's thinking or utterance.... "one who has known her kindness to little children, who has watched her little evidences of thoughtful care for her associates and friends, who has seen her put aside her own long-cherished rights that she might make the way of a new and untried officer easier, cannot forget the tenderer side of her character.... "but if would be vain for me to try to tell just what it was in miss mitchell that attracted us who loved her. it was this combination of great strength and independence, of deep affection and tenderness, breathed through and through with the sentiment of a perfectly genuine life, which has made for us one of the pilgrim-shrines of life the study in the observatory of vassar college where we have known her _at home_, surrounded by the evidences of her honorable professional career. she has been an impressive figure in our time, and one whose influence lives." introductory note on the 17th of december, 1831, a gold medal of the value of twenty ducats was founded, at the suggestion of professor schumacher, of altona, by his majesty frederic vi., at that time king of denmark, to be awarded to any person who should first discover a telescopic comet. this foundation and the conditions on which the medal would be awarded were announced to the public in the "astronomische nachrichten" for the 20th of march, 1832. the regulations underwent a revision after a few years, and in april, 1840 ("astronomische nachrichten," no. 400), were republished as follows: "1. the medal will be given to the first discoverer of any comet, which, at the time of its discovery, is invisible to the naked eye, and whose periodic time is unknown. "2. the discoverer, if a resident of any part of europe except great britain, is to make known his discovery to mr. schumacher at altona. if a resident in great britain, or any other quarter of the globe except the continent of europe, he is to make his discovery known directly to mr. francis baily, london. [since mr. baily's decease, g.b. airy, esq., astronomer royal, has been substituted in this and in the 7th and 8th articles of the regulations.] "3. this communication must be made by the _first post_ after the discovery. if there is no regular mail at the place of discovery, the first opportunity of any other kind must be made use of, without waiting for other observations. exact compliance with this condition is indispensable. if this condition is not complied with, and only one person discovers the comet, no medal will be given for the discovery. otherwise, the medal will be assigned to the discoverer who earliest complies with the condition. "4. the communication must not only state as exactly as possible the time of the discovery, in order to settle the question between rival claims, but also as near as may be the place of the comet, and the direction in which it is moving, as far as these points can be determined from the observations of one night. "5. if the observations of one night are not sufficient to settle these points, the enunciation of the discovery must still be made, in compliance with the third article. as soon as a second observation is made, it must be communicated in like manner with the first, and with it the longitude of the place where the discovery is made, unless it take place at some known observatory. the expectation of obtaining a second observation will never be received as a satisfactory reason for postponing the communication of the first. "6. the medal will be assigned twelve months after the discovery of the comet, and no claim will be admitted after that period. "7. messrs. baily and schumacher are to decide if a discovery has been made. if they differ, mr. gauss, of göttingen, is to decide. "8. messrs. baily and schumacher have agreed to communicate mutually to each other every announcement of a discovery. "altona, april, 1840." on the 1st of october, 1847, at half-past ten o'clock, p.m., a telescopic comet was discovered by miss maria mitchell, of nantucket, nearly vertical above polaris about five degrees. the further progress and history of the discovery will sufficiently appear from the following correspondence. on the 3d of october the same comet was seen at half-past seven, p.m., at rome, by father de vico, and information of the fact was immediately communicated by him to professor schumacher at altona. on the 7th of october, at twenty minutes past nine, p.m., it was observed by mr. w.r. dawes, at camden lodge, cranbrook, kent, in england, and on the 11th it was seen by madame rümker, the wife of the director of the observatory at hamburg. mr. schumacher, in announcing this last discovery, observes: [footnote: "astronomische nachrichten," no. 616.] "madame rümker has for several years been on the lookout for comets, and her persevering industry seemed at last about to be rewarded, when a letter was received from father de vico, addressed to the editor of this journal, from which it appeared that the same comet had been observed by him on the 3d instant at rome." not deeming it probable that his daughter had anticipated the observers of this country and europe in the discovery of this comet, no steps were taken by mr. mitchell with a view to obtaining the king of denmark's medal. prompt information, however, of the discovery was transmitted by mr. mitchell to his friend, william c. bond, esq., director of the observatory at cambridge. the observations of the messrs. bond upon the comet commenced on the 7th of october; and on the 30th were transmitted by me to mr. schumacher, for publication in the "astronomische nachrichten." it was stated in the memorandum of the messrs. bond that the comet was seen by miss mitchell on the 1st instant. this notice appeared in the "nachrichten" of dec. 9, 1847, and the priority of miss mitchell's discovery was immediately admitted throughout europe. my attention had been drawn to the subject of the king of denmark's comet medal by some allusion to it in my correspondence with professor schumacher, in reference to the discovery of telescopic comets by mr. george p. bond, of the observatory at cambridge. having learned some weeks after miss mitchell's discovery that no communication had been made on her behalf to the trustees of the medal, and aware that the regulations in this respect were enforced with strictness, i was apprehensive that it might be too late to supply the omission. still, however, as the spirit of the regulations had been complied with by mr. mitchell's letter to mr. bond of the 3d of october, it seemed worth while at least to make the attempt to procure the medal for his daughter. although the attempt might be unsuccessful, it would at any rate cause the priority of her discovery to be more authentically established than it might otherwise have been. i accordingly wrote to mr. mitchell for information on the subject, and applied for, and obtained from mr. bond, mr. mitchell's original letter to him of the 3d of october, with the nantucket postmark. these papers were transmitted to professor schumacher, with a letter dated 15th and 24th january. on the 8th of february i wrote a letter to my much esteemed friend, captain w.h. smyth, r.n., formerly president of the astronomical society at london, requesting him to interest himself with professor schumacher to obtain the medal for miss mitchell. captain smyth entered with great readiness into the matter, and addressed a note on the subject to mr. airy, the astronomer royal, at greenwich. mr. airy kindly wrote to professor schumacher without loss of time; but it was their united opinion that a compliance with the condition relative to immediate notice of a discovery was indispensable, and that it was consequently out of their power to award the medal to miss mitchell. mr. schumacher suggested, as the only means by which this difficulty could be overcome, an application to the danish government, through the american legation at copenhagen. conceiving that the correspondence could be carried on more promptly through the danish legation at washington, i addressed a letter on the 20th of april to mr. steene-billé, chargé d'affaires of the king of denmark in this country, and sent with it copies of the documents which had been forwarded to professor schumacher. mr. steene-billé, however, was of opinion that the application, if made at all, should be made through the american legation at copenhagen; but he expressed at the same time a confident opinion that, owing to the condition and political relations of denmark, the application would necessarily prove unavailing. it was at this time that the difficulties in schleswig-holstein were at their height, and it seemed hopeless at such a moment, and in face of the opinion of the official representative of the danish government in this country, to engage its attention to an affair of this kind. no further attempt was accordingly made by me, for some weeks, to pursue the matter. in fact, a report reached the united states that the medal had actually been awarded to father de vico. although this was believed by me to be an unfounded rumor, the regulations allowing one year for the presentation of claims, there was reason to apprehend that it proceeded from some quarter well informed as to what would probably take place at the expiration of the twelvemonth. on the 5th of august, father de vico, who had left rome in the spring in consequence of the troubles there, made a visit to cambridge, in company with the right rev. bishop fitzpatrick, of boston, and on this occasion informed me that he had received an intimation from professor schumacher that the comet-medal would be awarded to miss mitchell. i was disposed to think that father de vico labored under some misapprehension as to the purport of professor schumacher's communications, as afterwards appeared to be the case. i felt encouraged, however, by his statement not only to renew my correspondence on the subject with professor schumacher, but i determined, on the 8th of august, to address a letter to r.p. fleniken, esq., chargé d'affaires of the united states at copenhagen. this letter was accompanied with copies of the original papers. mr. fleniken entered with great zeal and interest into the subject. he lost no time in bringing it before the danish government by means of a letter to the count de knuth, the minister at that time for foreign affairs, and of another to the king of denmark himself. his majesty, with the most obliging promptness, ordered a reference of the case to professor schumacher, with directions to report thereon without delay. mr. schumacher had been for a long time in possession of the documents establishing miss mitchell's priority, which was, indeed, admitted throughout scientific europe. professor schumacher immediately made his report in favor of granting the medal to miss mitchell, and this report was accepted by the king. the result was forthwith communicated by the count de knuth to mr. fleniken, with the gratifying intelligence that the king had ordered the medal to be awarded to miss mitchell, and that it would be delivered to him for transmission as soon as it could be struck off. this has since been done. it must be regarded as a striking proof of an enlightened interest for the promotion of science, not less than of a kind regard for the rights and feelings of the individual most concerned in this decision, that the king of denmark should have bestowed his attention upon this subject, at a period of so much difficulty and alarm for europe in general and his own kingdom in particular. it would not have been possible to act more promptly in a season of the profoundest tranquillity. his majesty has on this occasion shown that he is animated by the same generous zeal for the encouragement of astronomical research which led his predecessor to found the medal; while he has performed an act of gracious courtesy toward a stranger in a distant land which must ever be warmly appreciated by her friends and countrymen. nor ought the obliging agency of the count de knuth, the minister of foreign affairs, to be passed without notice. the slightest indifference on his part, even the usual delays of office, would have prevented the application from reaching the king before the expiration of the twelvemonth within which all claims must, by the regulations, be presented. no one can reflect upon the pressure of business which must have existed in the foreign office at copenhagen during the past year, without feeling that the count de knuth must largely share his sovereign's zeal for science, as well as his love of justice. nothing else will account for the attention bestowed at such a political crisis on an affair of this kind. the same attention appears to have been given to the subject by his successor, count moltka. it was quite fortunate for the success of the application that the office of chargé d'affaires of the united states at copenhagen happened to be filled by a gentleman disposed to give it his prompt and persevering support. a matter of this kind, of course, lay without the province of his official duties. but no subject officially committed to him by the instructions of his government could have been more zealously pursued. on the very day on which my communication of the 8th of august reached him, mr. fleniken addressed his letters to the minister of foreign affairs and to the king, and he continued to give his attention to the subject till the object was happily effected, and the medal placed in his hands. the event itself, however insignificant in the great world of politics and business, is one of pleasing interest to the friends of american science, and it has been thought proper that the following record of it should be preserved in a permanent form. i have regretted the frequent recurrence of my own name in the correspondence, and have suppressed several letters of my own which could be spared, without rendering less intelligible the communications of the other parties, to whom the interest and merit of the transaction belong. edward everett. cambridge, 1st february, 1849. correspondence hon. william mitchell to william c. bond, esq., cambridge. "nantucket, 10 mo. 3d, 1847. "my dear friend: i write now merely to say that maria discovered a telescopic comet at half-past ten on the evening of the first instant, at that hour nearly vertical above polaris five degrees. last evening it had advanced westwardly; this evening still further, and nearing the pole. it does not bear illumination, but maria has obtained its right ascension and declination, and will not suffer me to announce it. pray tell me whether it is one of george's; if not, whether it has been seen by anybody. maria supposes it may be an old story. if quite convenient, just drop a line to her; it will oblige me much. i expect to leave home in a day or two, and shall be in boston next week, and i would like to have her hear from you before i can meet you. i hope it will not give thee much trouble amidst thy close engagements. "our regards are to all of you, most truly, "william mitchell." * * * * * hon. edward everett to hon. william mitchell. "cambridge, 10th january, 1848. "dear sir: i take the liberty to inquire of you whether any steps have been taken by you, on behalf of your daughter, by way of claiming the medal of the king of denmark for the first discovery of a telescopic comet. the regulations require that information of the discovery should be transmitted by the next mail to mr. airy, the astronomer royal, if the discovery is made elsewhere than on the continent of europe. if made in the united states, i understand from mr. schumacher that information may be sent to the danish minister at washington, who will forward it to mr. airy,--but it must be sent by next mail. "in consequence of non-compliance with these regulations, mr. george bond has on one occasion lost the medal. i trust this may not be the case with miss mitchell. "i am, dear sir, with much respect, faithfully yours, "edward everett." * * * * * extract from a letter of the hon. william mitchell to hon. edward everett. "nantucket, 1st mo. 15th, 1848. "esteemed friend: thy kind letter of the 10th instant reached me duly. no steps were taken by my daughter in claim of the medal of the danish king. on the night of the discovery, i was fully satisfied that it was a comet from its location, though its real motion at this time was so nearly opposite to that of the earth (the two bodies approaching each other) that its apparent motion was scarcely appreciable. i urged very strongly that it should be published immediately, but she resisted it as strongly, though she could but acknowledge her conviction that it was a comet. she remarked to me, 'if it is a new comet, our friends, the bonds, have seen it. it may be an old one, so far as relates to the discovery, and one which we have not followed.' she consented, however, that i should write to william c. bond, which i did by the first mail that left the island after the discovery. this letter did not reach my friend till the 6th or 7th, having been somewhat delayed here and also in the post-office at cambridge. "referring to my journal i find these words: 'maria will not consent to have me announce it as an original discovery.' "the stipulations of his majesty have, therefore, not been complied with, and the peculiar circumstances of the case, her sex, and isolated position, may not be sufficient to justify a suspension of the rules. nevertheless, it would gratify me that the generous monarch should know that there is a love of science even in this to him remote corner of the earth. "i am thine, my dear friend, most truly, "william mitchell." * * * * * hon. edward everett to professor schumacher, at altona. "cambridge, 15th january, 1848. "dear sir: your letter of the 27th october, accompanying the 'planeten-circulär,' reached me but a few days since. if you would be so good as to forward to the care of john miller, esq., 26 henrietta street, covent garden, london, any letter you may do me the favor to write to me, it would reach me promptly. "the regulations relative to the king of denmark's medal have not hitherto been understood in this country. i shall take care to give publicity to them. not only has mr. bond lost the medal to which you think he would have been entitled, [footnote: mr. schumacher had remarked to me, in his letter of the 27th of october, that mr. george p. bond would have received the medal for the comet first seen by him as a nebulous object on the 18th of february, 1846, if his observation made at that time had been communicated, according to the regulations, to the trustees of the medal.] but i fear the same has happened to miss mitchell, of nantucket, who discovered the comet of last october on the first day of that month. i think it was not seen in europe till the third. "i remain, dear sir, with great respect, faithfully yours, "edward everett." * * * * * hon. edward everett to hon. william mitchell. "cambridge, 18th january, 1848. "dear sir: i have your esteemed favor of the 15th, which reached me this day. i am fearful that the rigor deemed necessary in enforcing the regulations relative to the king of denmark's prize may prevent your daughter from receiving it. i learn from mr. schumacher's letter, that, besides mr. george bond, dr. bremeker lost the medal because he allowed a single post-day to pass before he announced his discovery. there could, in his case, be no difficulty in establishing the fact of his priority, nor any doubt of the good faith with which it was asserted. but inasmuch as miss mitchell's discovery was actually made known to mr. bond by the next mail which left your island, it is possible--barely possible--that this may be considered as a substantial compliance with the regulation. at any rate, it is worth trying; and if we can do no more we can establish the lady's claim to all the credit of the prior discovery. i shall therefore apply to mr. bond for the letter which you wrote, and if it contains nothing improper to be seen by others we will forward it to the danish minister at washington with a certified extract from your journal. i will have a certified copy of all these papers prepared and sent to mr. schumacher; and if any departure from the letter of the regulations is admissible, this would seem to be a case for it. i trust miss mitchell's retiring disposition will not lead her to oppose the taking of these steps. "i am, dear sir, with great respect, faithfully yours, [signed] "edward everett." * * * * * postscript to mr. everett's letter to professor schumacher of the 15th january, 1848. "p.s.--the foregoing was written to go by the steamer of the 15th, but was a few hours too late. i have since received some information in reference to the comet of october which leads me to hope that you may feel it in your power to award the medal to miss maria mitchell. miss mitchell saw the comet at half-past ten o'clock on the evening of october 1st. her father, a skilful astronomer, made an entry in his journal to that effect. on the third day of october he wrote a letter to mr. bond, the director of our observatory, announcing the discovery. this letter was despatched the following day, being the first post-day after the discovery of the comet. this letter i transmit to you, together with letters from mr. mitchell and mr. bond to myself. nantucket, as you are probably aware, is a small, secluded island, lying off the extreme point of the coast of massachusetts. mr. mitchell is a member of the executive council of massachusetts and a most respectable person. "as the claimant is a young lady of great diffidence, the place a retired island, remote from all the high-roads of communication; as the conditions have not been well understood in this country; and especially as there was a substantial compliance with them--i hope his majesty may think miss maria mitchell entitled to the medal. "cambridge, 24th january, 1848. * * * * * extract from a letter from mr. everett to captain w.h. smyth, r.n., late president of the royal astronomical society, london, dated cambridge, 8th february, 1848. "i have lately been making interest with mr. schumacher to cause the king of denmark's medal to be given to miss mitchell for the discovery of the comet to which her name has been given, if i mistake not, in the journal of your society as well as in the 'nachrichten.' she unquestionably discovered it at half-past ten on the evening of the 1st of october; it was not, i think, seen in europe till the 3d. her father, on the 3d, wrote a letter to mr. bond, the director of our observatory, informing him of this discovery; and this letter was sent by the first mail that left the little out-of-the-way island (nantucket) after the discovery. the _spirit_ of the regulations was therefore complied with. but as the _letter_ requires that the notice should be given either to the danish minister resident in the country or to mr. airy, if the discovery is made elsewhere than on the continent of europe, it is possible that some demur may be made. the precise terms of the regulations have not been sufficiently made known in this country. as the claim in this case is really a just one, the claimant a lady, industrious, vigilant, a good astronomer and mathematician, i cannot but hope she will succeed; and if you have the influence with schumacher which you ought to have, i would take it kindly if you would use it in her favor." * * * * * captain smyth to mr. everett. "3 cheyne walk, chelsea, 10th march, 1848. "my dear sir: on the receipt of your last letter, i forthwith wrote to the astronomer royal, urging the claims of miss mitchell, of nantucket, and he immediately replied, saying that he would lose no time in consulting his official colleague, mr. schumacher, on the subject. i have just received the accompanying letter from greenwich, by which you will perceive how the matter stands at present; i say at present, because, however the claim may be considered as to the technical form of application, there is no doubt whatever of her fully meriting the award. "i am, my dear sir, very faithfully yours, [signed] "w.h. smyth." * * * * * g.b. airy, esq., to captain smyth. "royal observatory, greenwich, 10th march, 1848. "my dear sir: i have received mr. schumacher's answer in regard to miss mitchell's supposed claims for the king of denmark's medal. we agree, without the smallest hesitation, that we cannot award the medal. we have in all cases acted strictly in conformity with the published rules; and i am convinced, and i believe that mr. schumacher is convinced, that it is absolutely necessary that we do not depart from them. "mr. schumacher suggests, as the only way in which miss mitchell's claim in equity could be urged, that application might be made on her part, through the american legation, to the king of denmark; and the king can, if he pleases, make exception to the usual rules. "i am, my dear sir, yours most truly, [signed] "g.b. airy." * * * * * hon. edward everett to r.p. fleniken. "cambridge, mass., 8th august, 1848. "dear sir: without the honor of your personal acquaintance, i take the liberty of addressing you on a subject which i am confident will interest you as a friend of american science. you are doubtless aware that by the liberality of one of the kings of denmark, the father, i believe, of his late majesty, a foundation was made for a gold medal to be given to the first discoverer of a telescopic comet. mr. schumacher, of altona, and mr. baily, of london (and since his decease mr. airy, astronomer royal at greenwich), were made the trustees of this foundation. among the regulations established for awarding the medal was this: that the discoverer should, by the first mail which leaves the place of his residence after the discovery, give notice thereof to mr. schumacher if the discovery is made on the continent of europe, and to mr. airy if made in any other part of the world; provided that, if the discovery be made in america, the notice may be given to the danish minister at washington. it has been deemed necessary to adhere with great strictness to this regulation, in order to prevent fraudulent claims. "on the first day of october last, at about half-past ten o'clock in the evening, a telescopic comet was discovered, in the island of nantucket, by miss maria mitchell, daughter of hon. w. mitchell, one of the executive council of this state. mr. mitchell made an entry of the discovery at the time in his journal. in consequence of miss mitchell's diffidence, she would not allow any publicity to be given to her discovery till its reality was ascertained. her father, however, by the first mail that left nantucket for the mainland, addressed a letter to mr. w.c. bond, director of the observatory in this place, acquainting him with his daughter's discovery. a copy of this letter i herewith transmit to you. the comet was not discovered in europe till the 3d of october, when it was seen by father de vico, the celebrated astronomer at rome. "you perceive from this statement that, if mr. mitchell had addressed his letter to the danish minister at washington instead of mr. bond, his daughter would have been entitled to the medal, under the strict terms of the regulations. but these regulations have not been generally understood in this country; and as the fact of miss mitchell's prior discovery is undoubted, and recognized throughout europe, it would be a pity that she should lose the medal on a mere technical punctilio. the comet is constantly called 'miss mitchell's comet' in the monthly journal of the royal astronomical society at london, and in the 'astronomische nachrichten,' the well-known astronomical journal, edited by mr. schumacher himself, at altona. father de vico (who, with his brothers of the society of jesuits, has left rome since the revolution there) was at this place (cambridge) three days ago, and spoke of miss mitchell's priority as an undoubted fact. "last winter i addressed a letter to mr. schumacher, acquainting him with the foregoing facts relative to the discovery, and transmitting to him the _original_ letter of mr. mitchell to mr. bond, dated 3d october, bearing the original nantucket postmark of the 4th. i also wrote to capt. w. h. smyth, late president of the royal astronomical society of england, desiring him to speak to mr. airy on the subject. he did so, and mr. airy wrote immediately to mr. schumacher. mr. schumacher in his reply expressed the opinion, in which mr. airy concurs, that _under the regulations_ it is not in their power to award the medal to miss mitchell. they suggest, however, that an application should be made, through the american legation at the danish court, to his majesty the king of denmark, for authority, under the present circumstances, to dispense with the literal fulfilment of the conditions. "it is on this subject that i take the liberty to ask your good offices. i accompany my letter with copies of a portion of the correspondence which has been had on the subject, and i venture to request you to address a note to the proper department of the danish government, to the end that authority should be given to messrs. schumacher and airy to award the medal to miss mitchell, _provided they are satisfied that she first discovered the comet_. "i will only add that, should you succeed in effecting this object, you will render a very acceptable service to all the friends of science in america. "i remain, dear sir, with high consideration, your obedient, faithful servant, [signed] "edward everett. "to r. p. fleniken, esq., chargé d'affaires of the united states of america at copenhagen." * * * * * r.p. fleniken, esq., to the count de knuth. "légation des etats unis d'amérique,} à copenhague, le 6 septembre, 1848. } "monsieur le ministre: j'ai l'honneur de remettre sous ce pli à votre excellence une lettre que j'ai reçue d'un de mes concitoyens les plus distingués, avec une correspondance touchant une matière à laquelle il me semble que le danemark ne soit guère moins intéressé que ne le sont les etats unis; le premier y ayant contribué le digne motif, l'autre en ayant heureusement accompli l'objet. "je recommande ces documents à l'examination attentive de votre excellence, sachant bien l'intérêt profond qu'elle ne manque jamais de prendre à de tels sujets, et la réputation éminente de cultivateur des sciences et de la littérature, dont elle jouit avec tant de justice. j'y ai joint une lettre de moi-même, adressée à sa majesté le roi de danemark. "la matière dont il est question, monsieur, sera d'autant plus intéressante à votre excellence, qu'on peut la regarder comme une voix de réponse adressée à l'ancienne scandinavie, proclaimant les prodiges merveilleux de la science moderne, des bords mêmes du vinland des vikinger hardis et entreprenants du dixième et de l'onzième siècles. "je prie votre excellence de vouloir bien soumettre tous les documents ci-joints à l'oeil de sa majesté, et dans le cas heureux ou vous seriez d'avis que ma compatriote, mlle. mitchell, puisse avec justice revendiquer la récompense génereuse instituée par le roi frédéric vi., alors, monsieur, je prie votre excellence de vouloir bien appuyer de ses propres estimables et puissantes recommandations l'application des amis de la jeune demoiselle. "je m'empresse à cette occasion, monsieur, de renouveler à votre excellence l'assurance de ma considération très distinguée. "r.p. fleniken. "a son excellence m. le comte de knuth, ministre d'etat, et chef du département des affaires etrangères. translation. [footnote: this and the other translations of the french letters are printed as received in this country.] "legation of the united states of america,} city of copenhagen, september 6th, 1848. } "sir: i have the honor to communicate to you a letter from a distinguished citizen of my own country, together with a correspondence relating to a subject in which denmark and the united states appear somewhat equally interested, the former in furnishing a laudable motive, and the latter as happily achieving the object. "i commend these papers to your careful examination, being well aware of the deep interest you take in all such subjects, and of the eminent reputation you so justly enjoy as a gentleman of science and of literature. they are accompanied by a letter from myself addressed to his majesty the king of denmark. "this subject will not be the less interesting to you, sir, as it would appear to be a returning voice addressed to ancient scandinavia, speaking of the wonderful achievements of modern science, from the 'vinland' of the hardy and enterprising 'northmen' of the tenth and the eleventh centuries. "i beg, therefore, that you will obligingly lay them all before his majesty, and should they happily impress you that my countrywoman, miss mitchell, is fairly entitled to the generous offering of king frederic vi., be pleased, sir, to accompany the application of her friends in her behalf by your own very valuable and potent recommendation. "i avail myself of this occasion to renew to your excellency the assurance of my most distinguished consideration. [signed]. "r.p. fleniken. "to his excellency the count de knuth, minister of state and chief of the department of foreign affairs. * * * * * r. p. fleniken, esq., to the king of denmark. "légation des etats unis d'amérique,} à copenhague, le 6 septembre, 1848. } "sire: le soussigné a l'honneur, par l'intermédiaire de m. votre ministre d'état et chef du département des affaires étrangères, de soumettre à votre majesté une lettre d'un citoyen très distingué des etats unis, accompagnée de la copie d'une correspondance concernant une matière a laquelle votre majesté, souverain également distingué par la libéralité généreuse qu'elle fait voir dans ses rapports sociaux et politiques, et par l'admiration ardente qu'elle manifeste envers la science et la littérature, ne peut manquer de prendre un vif intérêt. "le soussigné se félicite beaucoup d'être l'intermédiaire par les mains duquel ces documents arrivent sous l'oeil de votre majesté, étant persuadé que la lecture en fournira à votre majesté l'occasion de recourir avec une grande satisfaction patriotique, comme protecteur éminent des sciences, à l'institution d'un de ses illustres prédécesseurs; et ce souvenir de la haute position à laquelle le danemark s'est élevé dans les arts et les sciences, ne lui sera peut-être pas moins doux quand elle songe que c'est justement sur cette même côte, où déjà au dixième siècle l'intrépidité et l'esprit hardi de ses ancêtres scandinaves les avaient amenés à la découverte du grand continent occidental et à la fondation d'une colonie, que vient de s'accomplir cette conquête de la science, dont parlent les dits papiers. "le soussigné ose donc espérer, qu'à la suite d'une examination attentive des lettres ci-jointes, et desquelles il paraîtrait être généralement reconnu qu'à mlle. mitchell des etats unis est dû l'honneur d'avoir la première découvert la comète télescopique qui aujourd'hui porte son nom, que votre majesté ne trouvera point dans la réserve louable qui empêcha cette jeune demoiselle de se précipiter à la poursuite d'une renommée publique, une cause suffisante de lui refuser le prix de sa brilliante découverte; mais qu'au contraire elle donnera l'ordre de lui expédier la médaille, autant comme une récompense due à ses éminents talents scientifiques, que pour témoigner combien votre majesté sait apprécier cette modestie charmante qui s'opposa à ce que mlle. mitchell recherchât une célébrité publique et scientifique, avec le seul but de remplir une forme tout-à-fait technique. "le soussigné, chargé d'affaires des etats unis de l'amérique, saisit avec empressement cette occasion d'offrir à votre majesté l'expression de sa considération la plus haute et la plus distinguée. "r.p. fleniken. "à sa majesté frederic vii., roi de danemark, duc de slesvig et de holstein." * * * * * translation. "legation of the united states of america,} city of copenhagen, september 4th, 1848. } "sire: the undersigned has the honor, through your majesty's minister of state and chief of the department of foreign affairs, to communicate to you a letter from a very distinguished citizen of the united states, together with copies of a correspondence relating to a subject in which your majesty, alike distinguished for generous liberality in social and political affairs as a sovereign, as well as an ardent admirer of science and of literature, will doubtless feel a lively interest. "the undersigned is happy to be the medium through which those papers reach the eye of your majesty, feeling sensible that their perusal will furnish occasion to your majesty to recur with much national pleasure to the act of one of your illustrious predecessors as a distinguished patron of science; and this recurrence to the eminent position that denmark has attained in the arts and the sciences may perhaps not be the less pleasurable from the fact that the trophy of science to which the papers allude was achieved on the very coast where, as far back as the tenth century, the intrepidity and enterprise of your majesty's scandinavian ancestors first discovered and planted a colony upon the great western continent. "the undersigned therefore hopes that, after a careful examination of the accompanying papers, from which it would seem to be admitted that miss mitchell, of the united states, is entitled to the honor of first discovering the telescopic comet bearing her name, your majesty will not be able to perceive in that commendable delicacy which forbade her hastily seeking public notoriety a sufficient motive for withholding from her the reward of her eminent discovery; but, on the contrary, will direct the medal to be awarded to her, not only as a suitable encouragement to her distinguished scientific attainments, but also as evincing your majesty's appreciation of that beautiful virtue which withheld her from rushing into public and scientific renown merely to comply with a purely technical condition. "the undersigned, american chargé d'affaires, gladly improves this very pleasant occasion to tender to your majesty the expression of his high and most distinguished consideration. [signed] "r. p. fleniken. "to his majesty frederic vii., king of denmark, duke of schleswig and holstein." * * * * * the count de knuth to mr. fleniken. "copenhague, ce 6 octobre, 1848. "monsieur: j'ai eu l'honneur de recevoir votre office du 6 du passé, par lequel vous avez exprimé le désir que la médaille instituée par feu le roi frédéric vi., en récompense de la découverte de comètes télescopiques, fût accordée à mlle. maria mitchell, de nantucket dans les etats unis d'amérique. "après avoir examiné les pièces justificatives que vous avez bien voulu me communiquer relativement à cette réclamation, je ne saurais que partager votre avis, monsieur, qu'il paraît hors de doute que la découverte de la comète en question est effectivement dûe aux savantes recherches de mlle. mitchell; et que ce n'est que faute de n'avoir pas observé les formalités prescrites, qu'elle n'a point jusqu'ici reçu une marque de distinction à laquelle elle paraît avoir de si justes titres. "le savant astronome, le professeur schumacher, ayant également recommandé mlle. mitchell à la faveur qu'elle sollicite maintenant, je me suis empressé de référer cette question au roi, mon auguste maître, en mettant en même temps sous les yeux de sa majesté la lettre que vous lui avez adressée à ce sujet; et c'est avec bien du plaisir que je me vois aujourd'hui à même de vous faire part, monsieur, que sa majesté n'a point hésité à satisfaire à votre demande, en accordant à mlle. mitchell la médaille qu'elle ambitionne. "aussitôt que cette médaille sera frappée, je m'empresserai de vous la faire parvenir. "en attendant je saisis avec bien du plaisir cette occasion pour vous renouveler, monsieur, les assurances de ma considération très distinguée. "f.w. knuth. "à monsieur fleniken, chargé d'affaires des etats unis d'amérique." * * * * * translation. "copenhagen, 6th october, 1848. "sir: i have had the honor to receive your communication of the 6th ultimo, in which you express the desire that the medal instituted by his late majesty, frederic vi., as a reward for the discovery of telescopic comets, should be granted to miss maria mitchell, of nantucket, in the united states of america. "on examination of the justificatory pieces which you have been good enough to forward me, relating to her claim, i cannot do otherwise than participate in your opinion, sir, that it would appear to admit of no doubt that the discovery of the comet in question was really due to miss mitchell's learned researches; and that her not having as yet received a mark of distinction to which she seems to have such a just claim was entirely owing to her not having observed the prescribed forms. "the learned astronomer, professor schumacher, having likewise recommended miss mitchell to the favor which she now solicits, i hasten to refer this question to the king, my august master, at the same time laying before his majesty the letter which you have addressed to him on this subject; and i have much pleasure in being now enabled to inform you, sir, that his majesty has not hesitated to grant your request by awarding to miss mitchell the medal which she desires. "as soon as this medal is struck, i will have it forwarded to you, and meanwhile have much pleasure in availing myself of this occasion to renew to you, sir, the assurances of my most distinguished consideration. [signed] "f.w. knuth. "to mr. fleniken, chargé d'affaires of the united states of america." * * * * * mr. fleniken to the count de knuth. "légation des etats unis d'amérique, à copenhague, le 7 octobre, 1848. "monsieur: le soussigné a eu l'honneur de recevoir l'office que votre excellence lui a addressé en date d'hier pour lui faire part de la nouvelle heureuse que sa majesté, après avoir examiné les documents que vous avez bien voulu lui soumettre, ayant pour objet d'établir le fait que mlle. mitchell ait la première découvert la comète télescopique d'octobre de l'an dernier, a bien voulu trouver ces preuves suffisantes, et a ordonné qu'on frappe une médaille, afin de la lui faire présenter comme une marque de distinction que sa majesté croit qu'elle mérite en effet, quoiqu'elle n'ait pas rigoureusement observé les formalités prescrites par le roi frédéric vi., fondateur de ce don. "le soussigné s'empresse donc d'assurer votre excellence et en même temps de vous prier, monsieur, de vouloir bien faire parvenir cette assurance à sa majesté, que cet acte signalé de libéralité ne peut manquer d'être dignement et hautement apprécié par les institutions scientifiques des etats unis, par mlle. mitchell qui est l'objet de cette distinction généreuse, et par les nombreux amis scientifiques de cette dame; enfin, par tous ceux qui prennent de l'intérêt à la réussite heureuse des recherches astronomiques. "le soussigné ne peut terminer cette communication sans exprimer à votre excellence (en la priant de porter aussi ses sentiments à la connaissance de sa majesté) sa vive appréciation de ce noble et éclatant acte de justice, si promptement et si généreusement rendu à sa jeune compatriote par le roi de danemark, et il saisit avec empressement cette occasion de renouveler à votre excellence les assurances de sa considération très distinguée. "r.p. fleniken. "à son excellence m. le comte de knuth, ministre d'etat et chef du département des affaires etrangères." * * * * * translation. "legation of the united states,} copenhagen, october 7th, 1848. } "sir: the undersigned has the honor to acknowledge the receipt of your excellency's communication of yesterday's date, conveying to him the gratifying intelligence that his majesty, from an examination of the evidence which you obligingly laid before him, tending to establish the fact of miss mitchell's having discovered the telescopic comet of october, last, has been pleased to consider it quite satisfactory, and has ordered a medal to be struck for her as a mark of distinction to which his majesty deems her entitled, notwithstanding her omission to comply with the prescribed conditions of frederic vi., who instituted the donation. "the undersigned, therefore, begs to express to you, sir, and through you to his majesty, the assurance that this eminent act of liberality cannot fail to be duly and highly appreciated by the scientific institutions of his own country, by miss mitchell herself, who is the object of this generous distinction, and by her numerous scientific friends, as well as by all who feel an interest in successful astronomical achievements. "the undersigned cannot close this communication without expressing to you and to the king his own unaffected appreciation of this noble and distinguished act of justice, so promptly and so generously bestowed upon his unobtrusive countrywoman by the king of denmark, and avails himself of the occasion to renew to your excellency the assurance of his most distinguished consideration. [signed] "r.p. fleniken. "to his excellency the count de knuth, minister of state, etc., etc., etc." jill r. diffendal, barb grow pebareka@iexpress.net.au christine l. hall goleta, ca. usa pamela l. hall pamhall@www.edu great astronomers by sir robert s. ball d.sc. ll.d. f.r.s. lowndean professor of astronomy and geometry in the university of cambridge author of "in starry realms" "in the high heavens" etc. with numerous illustrations [plate: greenwich observatory.] preface. it has been my object in these pages to present the life of each astronomer in such detail as to enable the reader to realise in some degree the man's character and surroundings; and i have endeavoured to indicate as clearly as circumstances would permit the main features of the discoveries by which he has become known. there are many types of astronomers--from the stargazer who merely watches the heavens, to the abstract mathematician who merely works at his desk; it has, consequently, been necessary in the case of some lives to adopt a very different treatment from that which seemed suitable for others. while the work was in progress, some of the sketches appeared in "good words." the chapter on brinkley has been chiefly derived from an article on the "history of dunsink observatory," which was published on the occasion of the tercentenary celebration of the university of dublin in 1892, and the life of sir william rowan hamilton is taken, with a few alterations and omissions, from an article contributed to the "quarterly review" on graves' life of the great mathematician. the remaining chapters now appear for the first time. for many of the facts contained in the sketch of the late professor adams, i am indebted to the obituary notice written by my friend dr. j. w. l. glaisher, for the royal astronomical society; while with regard to the late sir george airy, i have a similar acknowledgment to make to professor h. h. turner. to my friend dr. arthur a. rambaut i owe my hearty thanks for his kindness in aiding me in the revision of the work. r.s.b. the observatory, cambridge. october, 1895 contents. introduction. ptolemy. copernicus. tycho brahe. galileo. kepler. isaac newton. flamsteed. halley. bradley. william herschel. laplace. brinkley. john herschel. the earl of rosse. airy. hamilton. le verrier. adams. list of illustrations. the observatory, greenwich. ptolemy. ptolemy's planetary scheme. ptolemy's theory of the movement of mars. thorn, from an old print. copernicus. frauenburg, from an old print. explanation of planetary movements. tycho brahe. tycho's cross staff. tycho's "new star" sextant of 1572. tycho's trigonic sextant. tycho's astronomic sextant. tycho's equatorial armillary. the great augsburg quadrant. tycho's "new scheme of the terrestrial system," 1577. uraniborg and its grounds. ground-plan of the observatory. the observatory of uraniborg, island of hven. effigy on tycho's tomb at prague. by permission of messrs. a. & c. black. tycho's mural quadrant, uraniborg. galileo's pendulum. galileo. the villa arcetri. facsimile sketch of lunar surface by galileo. crest of galileo's family. kepler's system of regular solids. kepler. symbolical representation of the planetary system. the commemoration of the rudolphine tables. woolsthorpe manor. trinity college, cambridge. diagram of a sunbeam. isaac newton. sir isaac newton's little reflector. sir isaac newton's sun-dial. sir isaac newton's telescope. sir isaac newton's astrolabe. sir isaac newton's sun-dial in the royal society. flamsteed's house. flamsteed. halley. greenwich observatory in halley's time. 7, new king street, bath. from a photograph by john poole, bath. william herschel. caroline herschel. street view, herschel house, slough. from a photograph by hill & saunders, eton. garden view, herschel house, slough. from a photograph by hill & saunders, eton. observatory, herschel house, slough. from a photograph by hill & saunders, eton. the 40-foot telescope, herschel house, slough. from a photograph by hill & saunders, eton. laplace. the observatory, dunsink. from a photograph by w. lawrence, dublin. astronometer made by sir john herschel. sir john herschel. nebula in southern hemisphere. the cluster in the centaur. observatory at feldhausen. granite column at feldhausen. the earl of rosse. birr castle. from a photograph by w. lawrence, dublin. the mall, parsonstown. from a photograph by w. lawrence, dublin. lord rosse's telescope. from a photograph by w. lawrence, dublin. roman catholic church, parsonstown. from a photograph by w. lawrence, dublin. airy. from a photograph by e.p. adams, greenwich. hamilton. adams. the observatory, cambridge. introduction. of all the natural sciences there is not one which offers such sublime objects to the attention of the inquirer as does the science of astronomy. from the earliest ages the study of the stars has exercised the same fascination as it possesses at the present day. among the most primitive peoples, the movements of the sun, the moon, and the stars commanded attention from their supposed influence on human affairs. the practical utilities of astronomy were also obvious in primeval times. maxims of extreme antiquity show how the avocations of the husbandman are to be guided by the movements of the heavenly bodies. the positions of the stars indicated the time to plough, and the time to sow. to the mariner who was seeking a way across the trackless ocean, the heavenly bodies offered the only reliable marks by which his path could be guided. there was, accordingly, a stimulus both from intellectual curiosity and from practical necessity to follow the movements of the stars. thus began a search for the causes of the ever-varying phenomena which the heavens display. many of the earliest discoveries are indeed prehistoric. the great diurnal movement of the heavens, and the annual revolution of the sun, seem to have been known in times far more ancient than those to which any human monuments can be referred. the acuteness of the early observers enabled them to single out the more important of the wanderers which we now call planets. they saw that the star-like objects, jupiter, saturn, and mars, with the more conspicuous venus, constituted a class of bodies wholly distinct from the fixed stars among which their movements lay, and to which they bear such a superficial resemblance. but the penetration of the early astronomers went even further, for they recognized that mercury also belongs to the same group, though this particular object is seen so rarely. it would seem that eclipses and other phenomena were observed at babylon from a very remote period, while the most ancient records of celestial observations that we possess are to be found in the chinese annals. the study of astronomy, in the sense in which we understand the word, may be said to have commenced under the reign of the ptolemies at alexandria. the most famous name in the science of this period is that of hipparchus who lived and worked at rhodes about the year 160bc. it was his splendid investigations that first wrought the observed facts into a coherent branch of knowledge. he recognized the primary obligation which lies on the student of the heavens to compile as complete an inventory as possible of the objects which are there to be found. hipparchus accordingly commenced by undertaking, on a small scale, a task exactly similar to that on which modern astronomers, with all available appliances of meridian circles, and photographic telescopes, are constantly engaged at the present day. he compiled a catalogue of the principal fixed stars, which is of special value to astronomers, as being the earliest work of its kind which has been handed down. he also studied the movements of the sun and the moon, and framed theories to account for the incessant changes which he saw in progress. he found a much more difficult problem in his attempt to interpret satisfactorily the complicated movements of the planets. with the view of constructing a theory which should give some coherent account of the subject, he made many observations of the places of these wandering stars. how great were the advances which hipparchus accomplished may be appreciated if we reflect that, as a preliminary task to his more purely astronomical labours, he had to invent that branch of mathematical science by which alone the problems he proposed could be solved. it was for this purpose that he devised the indispensable method of calculation which we now know so well as trigonometry. without the aid rendered by this beautiful art it would have been impossible for any really important advance in astronomical calculation to have been effected. but the discovery which shows, beyond all others, that hipparchus possessed one of the master-minds of all time was the detection of that remarkable celestial movement known as the precession of the equinoxes. the inquiry which conducted to this discovery involved a most profound investigation, especially when it is remembered that in the days of hipparchus the means of observation of the heavenly bodies were only of the rudest description, and the available observations of earlier dates were extremely scanty. we can but look with astonishment on the genius of the man who, in spite of such difficulties, was able to detect such a phenomenon as the precession, and to exhibit its actual magnitude. i shall endeavour to explain the nature of this singular celestial movement, for it may be said to offer the first instance in the history of science in which we find that combination of accurate observation with skilful interpretation, of which, in the subsequent development of astronomy, we have so many splendid examples. the word equinox implies the condition that the night is equal to the day. to a resident on the equator the night is no doubt equal to the day at all times in the year, but to one who lives on any other part of the earth, in either hemisphere, the night and the day are not generally equal. there is, however, one occasion in spring, and another in autumn, on which the day and the night are each twelve hours at all places on the earth. when the night and day are equal in spring, the point which the sun occupies on the heavens is termed the vernal equinox. there is similarly another point in which the sun is situated at the time of the autumnal equinox. in any investigation of the celestial movements the positions of these two equinoxes on the heavens are of primary importance, and hipparchus, with the instinct of genius, perceived their significance, and commenced to study them. it will be understood that we can always define the position of a point on the sky with reference to the surrounding stars. no doubt we do not see the stars near the sun when the sun is shining, but they are there nevertheless. the ingenuity of hipparchus enabled him to determine the positions of each of the two equinoxes relatively to the stars which lie in its immediate vicinity. after examination of the celestial places of these points at different periods, he was led to the conclusion that each equinox was moving relatively to the stars, though that movement was so slow that twenty five thousand years would necessarily elapse before a complete circuit of the heavens was accomplished. hipparchus traced out this phenomenon, and established it on an impregnable basis, so that all astronomers have ever since recognised the precession of the equinoxes as one of the fundamental facts of astronomy. not until nearly two thousand years after hipparchus had made this splendid discovery was the explanation of its cause given by newton. from the days of hipparchus down to the present hour the science of astronomy has steadily grown. one great observer after another has appeared from time to time, to reveal some new phenomenon with regard to the celestial bodies or their movements, while from time to time one commanding intellect after another has arisen to explain the true import of the facts of observations. the history of astronomy thus becomes inseparable from the history of the great men to whose labours its development is due. in the ensuing chapters we have endeavoured to sketch the lives and the work of the great philosophers, by whose labours the science of astronomy has been created. we shall commence with ptolemy, who, after the foundations of the science had been laid by hipparchus, gave to astronomy the form in which it was taught throughout the middle ages. we shall next see the mighty revolution in our conceptions of the universe which are associated with the name of copernicus. we then pass to those periods illumined by the genius of galileo and newton, and afterwards we shall trace the careers of other more recent discoverers, by whose industry and genius the boundaries of human knowledge have been so greatly extended. our history will be brought down late enough to include some of the illustrious astronomers who laboured in the generation which has just passed away. ptolemy. [plate: ptolemy.] the career of the famous man whose name stands at the head of this chapter is one of the most remarkable in the history of human learning. there may have been other discoverers who have done more for science than ever ptolemy accomplished, but there never has been any other discoverer whose authority on the subject of the movements of the heavenly bodies has held sway over the minds of men for so long a period as the fourteen centuries during which his opinions reigned supreme. the doctrines he laid down in his famous book, "the almagest," prevailed throughout those ages. no substantial addition was made in all that time to the undoubted truths which this work contained. no important correction was made of the serious errors with which ptolemy's theories were contaminated. the authority of ptolemy as to all things in the heavens, and as to a good many things on the earth (for the same illustrious man was also a diligent geographer), was invariably final. though every child may now know more of the actual truths of the celestial motions than ever ptolemy knew, yet the fact that his work exercised such an astonishing effect on the human intellect for some sixty generations, shows that it must have been an extraordinary production. we must look into the career of this wonderful man to discover wherein lay the secret of that marvellous success which made him the unchallenged instructor of the human race for such a protracted period. unfortunately, we know very little as to the personal history of ptolemy. he was a native of egypt, and though it has been sometimes conjectured that he belonged to the royal families of the same name, yet there is nothing to support such a belief. the name, ptolemy, appears to have been a common one in egypt in those days. the time at which he lived is fixed by the fact that his first recorded observation was made in 127 ad, and his last in 151 ad. when we add that he seems to have lived in or near alexandria, or to use his own words, "on the parallel of alexandria," we have said everything that can be said so far as his individuality is concerned. ptolemy is, without doubt, the greatest figure in ancient astronomy. he gathered up the wisdom of the philosophers who had preceded him. he incorporated this with the results of his own observations, and illumined it with his theories. his speculations, even when they were, as we now know, quite erroneous, had such an astonishing verisimilitude to the actual facts of nature that they commanded universal assent. even in these modern days we not unfrequently find lovers of paradox who maintain that ptolemy's doctrines not only seem true, but actually are true. in the absence of any accurate knowledge of the science of mechanics, philosophers in early times were forced to fall back on certain principles of more or less validity, which they derived from their imagination as to what the natural fitness of things ought to be. there was no geometrical figure so simple and so symmetrical as a circle, and as it was apparent that the heavenly bodies pursued tracks which were not straight lines, the conclusion obviously followed that their movements ought to be circular. there was no argument in favour of this notion, other than the merely imaginary reflection that circular movement, and circular movement alone, was "perfect," whatever "perfect" may have meant. it was further believed to be impossible that the heavenly bodies could have any other movements save those which were perfect. assuming this, it followed, in ptolemy's opinion, and in that of those who came after him for fourteen centuries, that all the tracks of the heavenly bodies were in some way or other to be reduced to circles. ptolemy succeeded in devising a scheme by which the apparent changes that take place in the heavens could, so far as he knew them, be explained by certain combinations of circular movement. this seemed to reconcile so completely the scheme of things celestial with the geometrical instincts which pointed to the circle as the type of perfect movement, that we can hardly wonder ptolemy's theory met with the astonishing success that attended it. we shall, therefore, set forth with sufficient detail the various steps of this famous doctrine. ptolemy commences with laying down the undoubted truth that the shape of the earth is globular. the proofs which he gives of this fundamental fact are quite satisfactory; they are indeed the same proofs as we give today. there is, first of all, the well-known circumstance of which our books on geography remind us, that when an object is viewed at a distance across the sea, the lower part of the object appears cut off by the interposing curved mass of water. the sagacity of ptolemy enabled him to adduce another argument, which, though not quite so obvious as that just mentioned, demonstrates the curvature of the earth in a very impressive manner to anyone who will take the trouble to understand it. ptolemy mentions that travellers who went to the south reported, that, as they did so, the appearance of the heavens at night underwent a gradual change. stars that they were familiar with in the northern skies gradually sank lower in the heavens. the constellation of the great bear, which in our skies never sets during its revolution round the pole, did set and rise when a sufficient southern latitude had been attained. on the other hand, constellations new to the inhabitants of northern climes were seen to rise above the southern horizon. these circumstances would be quite incompatible with the supposition that the earth was a flat surface. had this been so, a little reflection will show that no such changes in the apparent movements of the stars would be the consequence of a voyage to the south. ptolemy set forth with much insight the significance of this reasoning, and even now, with the resources of modern discoveries to help us, we can hardly improve upon his arguments. ptolemy, like a true philosopher disclosing a new truth to the world, illustrated and enforced his subject by a variety of happy demonstrations. i must add one of them, not only on account of its striking nature, but also because it exemplifies ptolemy's acuteness. if the earth were flat, said this ingenious reasoner, sunset must necessarily take place at the same instant, no matter in what country the observer may happen to be placed. ptolemy, however, proved that the time of sunset did vary greatly as the observer's longitude was altered. to us, of course, this is quite obvious; everybody knows that the hour of sunset may have been reached in great britain while it is still noon on the western coast of america. ptolemy had, however, few of those sources of knowledge which are now accessible. how was he to show that the sun actually did set earlier at alexandria than it would in a city which lay a hundred miles to the west? there was no telegraph wire by which astronomers at the two places could communicate. there was no chronometer or watch which could be transported from place to place; there was not any other reliable contrivance for the keeping of time. ptolemy's ingenuity, however, pointed out a thoroughly satisfactory method by which the times of sunset at two places could be compared. he was acquainted with the fact, which must indeed have been known from the very earliest times, that the illumination of the moon is derived entirely from the sun. he knew that an eclipse of the moon was due to the interposition of the earth which cuts off the light of the sun. it was, therefore, plain that an eclipse of the moon must be a phenomenon which would begin at the same instant from whatever part of the earth the moon could be seen at the time. ptolemy, therefore, brought together from various quarters the local times at which different observers had recorded the beginning of a lunar eclipse. he found that the observers to the west made the time earlier and earlier the further away their stations were from alexandria. on the other hand, the eastern observers set down the hour as later than that at which the phenomenon appeared at alexandria. as these observers all recorded something which indeed appeared to them simultaneously, the only interpretation was, that the more easterly a place the later its time. suppose there were a number of observers along a parallel of latitude, and each noted the hour of sunset to be six o'clock, then, since the eastern times are earlier than western times, 6 p.m. at one station a will correspond to 5 p.m. at a station b sufficiently to the west. if, therefore, it is sunset to the observer at a, the hour of sunset will not yet be reached for the observer at b. this proves conclusively that the time of sunset is not the same all over the earth. we have, however, already seen that the apparent time of sunset would be the same from all stations if the earth were flat. when ptolemy, therefore, demonstrated that the time of sunset was not the same at various places, he showed conclusively that the earth was not flat. as the same arguments applied to all parts of the earth where ptolemy had either been himself, or from which he could gain the necessary information, it followed that the earth, instead of being the flat plain, girdled with an illimitable ocean, as was generally supposed, must be in reality globular. this led at once to a startling consequence. it was obvious that there could be no supports of any kind by which this globe was sustained; it therefore followed that the mighty object must be simply poised in space. this is indeed an astonishing doctrine to anyone who relies on what merely seems the evidence of the senses, without giving to that evidence its due intellectual interpretation. according to our ordinary experience, the very idea of an object poised without support in space, appears preposterous. would it not fall? we are immediately asked. yes, doubtless it could not remain poised in any way in which we try the experiment. we must, however, observe that there are no such ideas as upwards or downwards in relation to open space. to say that a body falls downwards, merely means that it tries to fall as nearly as possible towards the centre of the earth. there is no one direction along which a body will tend to move in space, in preference to any other. this may be illustrated by the fact that a stone let fall at new zealand will, in its approach towards the earth's centre, be actually moving upwards as far as any locality in our hemisphere is concerned. why, then, argued ptolemy, may not the earth remain poised in space, for as all directions are equally upward or equally downward, there seems no reason why the earth should require any support? by this reasoning he arrives at the fundamental conclusion that the earth is a globular body freely lying in space, and surrounded above, below, and on all sides by the glittering stars of heaven. the perception of this sublime truth marks a notable epoch in the history of the gradual development of the human intellect. no doubt, other philosophers, in groping after knowledge, may have set forth certain assertions that are more or less equivalent to this fundamental truth. it is to ptolemy we must give credit, however, not only for announcing this doctrine, but for demonstrating it by clear and logical argument. we cannot easily project our minds back to the conception of an intellectual state in which this truth was unfamiliar. it may, however, be well imagined that, to one who thought the earth was a flat plain of indefinite extent, it would be nothing less than an intellectual convulsion for him to be forced to believe that he stood upon a spherical earth, forming merely a particle relatively to the immense sphere of the heavens. what ptolemy saw in the movements of the stars led him to the conclusion that they were bright points attached to the inside of a tremendous globe. the movements of this globe which carried the stars were only compatible with the supposition that the earth occupied its centre. the imperceptible effect produced by a change in the locality of the observer on the apparent brightness of the stars made it plain that the dimensions of the terrestrial globe must be quite insignificant in comparison with those of the celestial sphere. the earth might, in fact, be regarded as a grain of sand while the stars lay upon a globe many yards in diameter. so tremendous was the revolution in human knowledge implied by this discovery, that we can well imagine how ptolemy, dazzled as it were by the fame which had so justly accrued to him, failed to make one further step. had he made that step, it would have emancipated the human intellect from the bondage of fourteen centuries of servitude to a wholly monstrous notion of this earth's importance in the scheme of the heavens. the obvious fact that the sun, the moon, and the stars rose day by day, moved across the sky in a glorious never-ending procession, and duly set when their appointed courses had been run, demanded some explanation. the circumstance that the fixed stars preserved their mutual distances from year to year, and from age to age, appeared to ptolemy to prove that the sphere which contained those stars, and on whose surface they were believed by him to be fixed, revolved completely around the earth once every day. he would thus account for all the phenomena of rising and setting consistently with the supposition that our globe was stationary. probably this supposition must have appeared monstrous, even to ptolemy. he knew that the earth was a gigantic object, but, large as it may have been, he knew that it was only a particle in comparison with the celestial sphere, yet he apparently believed, and certainly succeeded in persuading other men to believe, that the celestial sphere did actually perform these movements. ptolemy was an excellent geometer. he knew that the rising and the setting of the sun, the moon, and the myriad stars, could have been accounted for in a different way. if the earth turned round uniformly once a day while poised at the centre of the sphere of the heavens, all the phenomena of rising and setting could be completely explained. this is, indeed, obvious after a moment's reflection. consider yourself to be standing on the earth at the centre of the heavens. there are stars over your head, and half the contents of the heavens are visible, while the other half are below your horizon. as the earth turns round, the stars over your head will change, and unless it should happen that you have taken up your position at either of the poles, new stars will pass into your view, and others will disappear, for at no time can you have more than half of the whole sphere visible. the observer on the earth would, therefore, say that some stars were rising, and that some stars were setting. we have, therefore, two totally distinct methods, each of which would completely explain all the observed facts of the diurnal movement. one of these suppositions requires that the celestial sphere, bearing with it the stars and other celestial bodies, turns uniformly around an invisible axis, while the earth remains stationary at the centre. the other supposition would be, that it is the stupendous celestial sphere which remains stationary, while the earth at the centre rotates about the same axis as the celestial sphere did before, but in an opposite direction, and with a uniform velocity which would enable it to complete one turn in twenty-four hours. ptolemy was mathematician enough to know that either of these suppositions would suffice for the explanation of the observed facts. indeed, the phenomena of the movements of the stars, so far as he could observe them, could not be called upon to pronounce which of these views was true, and which was false. ptolemy had, therefore, to resort for guidance to indirect lines of reasoning. one of these suppositions must be true, and yet it appeared that the adoption of either was accompanied by a great difficulty. it is one of his chief merits to have demonstrated that the celestial sphere was so stupendous that the earth itself was absolutely insignificant in comparison therewith. if, then, this stupendous sphere rotated once in twenty-four hours, the speed with which the movement of some of the stars must be executed would be so portentous as to seem well-nigh impossible. it would, therefore, seem much simpler on this ground to adopt the other alternative, and to suppose the diurnal movements were due to the rotation of the earth. here ptolemy saw, or at all events fancied he saw, objections of the weightiest description. the evidence of the senses appeared directly to controvert the supposition that this earth is anything but stationary. ptolemy might, perhaps, have dismissed this objection on the ground that the testimony of the senses on such a matter should be entirely subordinated to the interpretation which our intelligence would place upon the facts to which the senses deposed. another objection, however, appeared to him to possess the gravest moment. it was argued that if the earth were rotating, there is nothing to make the air participate in this motion, mankind would therefore be swept from the earth by the furious blasts which would arise from the movement of the earth through an atmosphere at rest. even if we could imagine that the air were carried round with the earth, the same would not apply, so thought ptolemy, to any object suspended in the air. so long as a bird was perched on a tree, he might very well be carried onward by the moving earth, but the moment he took wing, the ground would slip from under him at a frightful pace, so that when he dropped down again he would find himself at a distance perhaps ten times as great as that which a carrier-pigeon or a swallow could have traversed in the same time. some vague delusion of this description seems even still to crop up occasionally. i remember hearing of a proposition for balloon travelling of a very remarkable kind. the voyager who wanted to reach any other place in the same latitude was simply to ascend in a balloon, and wait there till the rotation of the earth conveyed the locality which happened to be his destination directly beneath him, whereupon he was to let out the gas and drop down! ptolemy knew quite enough natural philosophy to be aware that such a proposal for locomotion would be an utter absurdity; he knew that there was no such relative shift between the air and the earth as this motion would imply. it appeared to him to be necessary that the air should lag behind, if the earth had been animated by a movement of rotation. in this he was, as we know, entirely wrong. there were, however, in his days no accurate notions on the subject of the laws of motion. assiduous as ptolemy may have been in the study of the heavenly bodies, it seems evident that he cannot have devoted much thought to the phenomena of motion of terrestrial objects. simple, indeed, are the experiments which might have convinced a philosopher much less acute than ptolemy, that, if the earth did revolve, the air must necessarily accompany it. if a rider galloping on horseback tosses a ball into the air, it drops again into his hand, just as it would have done had he been remaining at rest during the ball's flight; the ball in fact participates in the horizontal motion, so that though it really describes a curve as any passer-by would observe, yet it appears to the rider himself merely to move up and down in a straight line. this fact, and many others similar to it, demonstrate clearly that if the earth were endowed with a movement of rotation, the atmosphere surrounding it must participate in that movement. ptolemy did not know this, and consequently he came to the conclusion that the earth did not rotate, and that, therefore, notwithstanding the tremendous improbability of so mighty an object as the celestial sphere spinning round once in every twenty-four hours, there was no course open except to believe that this very improbable thing did really happen. thus it came to pass that ptolemy adopted as the cardinal doctrine of his system a stationary earth poised at the centre of the celestial sphere, which stretched around on all sides at a distance so vast that the diameter of the earth was an inappreciable point in comparison therewith. ptolemy having thus deliberately rejected the doctrine of the earth's rotation, had to make certain other entirely erroneous suppositions. it was easily seen that each star required exactly the same period for the performance of a complete revolution of the heavens. ptolemy knew that the stars were at enormous distances from the earth, though no doubt his notions on this point came very far short of what we know to be the reality. if the stars had been at very varied distances, then it would be so wildly improbable that they should all accomplish their revolutions in the same time, that ptolemy came to the conclusion that they must be all at the same distance, that is, that they must be all on the surface of a sphere. this view, however erroneous, was corroborated by the obvious fact that the stars in the constellations preserved their relative places unaltered for centuries. thus it was that ptolemy came to the conclusion that they were all fixed on one spherical surface, though we are not informed as to the material of this marvellous setting which sustained the stars like jewels. nor should we hastily pronounce this doctrine to be absurd. the stars do appear to lie on the surface of a sphere, of which the observer is at the centre; not only is this the aspect which the skies present to the untechnical observer, but it is the aspect in which the skies are presented to the most experienced astronomer of modern days. no doubt he knows well that the stars are at the most varied distances from him; he knows that certain stars are ten times, or a hundred times, or a thousand times, as far as other stars. nevertheless, to his eye the stars appear on the surface of the sphere, it is on that surface that his measurements of the relative places of the stars are made; indeed, it may be said that almost all the accurate observations in the observatory relate to the places of the stars, not as they really are, but as they appear to be projected on that celestial sphere whose conception we owe to the genius of ptolemy. this great philosopher shows very ingeniously that the earth must be at the centre of the sphere. he proves that, unless this were the case, each star would not appear to move with the absolute uniformity which does, as a matter of fact, characterise it. in all these reasonings we cannot but have the most profound admiration for the genius of ptolemy, even though he had made an error so enormous in the fundamental point of the stability of the earth. another error of a somewhat similar kind seemed to ptolemy to be demonstrated. he had shown that the earth was an isolated object in space, and being such was, of course, capable of movement. it could either be turned round, or it could be moved from one place to another. we know that ptolemy deliberately adopted the view that the earth did not turn round; he had then to investigate the other question, as to whether the earth was animated by any movement of translation. he came to the conclusion that to attribute any motion to the earth would be incompatible with the truths at which he had already arrived. the earth, argued ptolemy, lies at the centre of the celestial sphere. if the earth were to be endowed with movement, it would not lie always at this point, it must, therefore, shift to some other part of the sphere. the movements of the stars, however, preclude the possibility of this; and, therefore, the earth must be as devoid of any movement of translation as it is devoid of rotation. thus it was that ptolemy convinced himself that the stability of the earth, as it appeared to the ordinary senses, had a rational philosophical foundation. not unfrequently it is the lot of the philosophers to contend against the doctrines of the vulgar, but when it happens, as in the case of ptolemy's researches, that the doctrines of the vulgar are corroborated by philosophical investigation which bear the stamp of the highest authority, it is not to be wondered at that such doctrines should be deemed well-nigh impregnable. in this way we may, perhaps, account for the remarkable fact that the theories of ptolemy held unchallenged sway over the human intellect for the vast period already mentioned. up to the present we have been speaking only of those primary motions of the heavens, by which the whole sphere appeared to revolve once every twenty-four hours. we have now to discuss the remarkable theories by which ptolemy endeavoured to account for the monthly movement of the moon, for the annual movement of the sun, and for the periodic movements of the planets which had gained for them the titles of the wandering stars. possessed with the idea that these movements must be circular, or must be capable, directly or indirectly, of being explained by circular movements, it seemed obvious to ptolemy, as indeed it had done to previous astronomers, that the track of the moon through the stars was a circle of which the earth is the centre. a similar movement with a yearly period must also be attributed to the sun, for the changes in the positions of the constellations in accordance with the progress of the seasons, placed it beyond doubt that the sun made a circuit of the celestial sphere, even though the bright light of the sun prevented the stars in its vicinity, from being seen in daylight. thus the movements both of the sun and the moon, as well as the diurnal rotation of the celestial sphere, seemed to justify the notion that all celestial movements must be "perfect," that is to say, described uniformly in those circles which were the only perfect curves. the simplest observations, however, show that the movements of the planets cannot be explained in this simple fashion. here the geometrical genius of ptolemy shone forth, and he devised a scheme by which the apparent wanderings of the planets could be accounted for without the introduction of aught save "perfect" movements. to understand his reasoning, let us first set forth clearly those facts of observation which require to be explained. i shall take, in particular, two planets, venus and mars, as these illustrate, in the most striking manner, the peculiarities of the inner and the outer planets respectively. the simplest observations would show that venus did not move round the heavens in the same fashion as the sun or the moon. look at the evening star when brightest, as it appears in the west after sunset. instead of moving towards the east among the stars, like the sun or the moon, we find, week after week, that venus is drawing in towards the sun, until it is lost in the sunbeams. then the planet emerges on the other side, not to be seen as an evening star, but as a morning star. in fact, it was plain that in some ways venus accompanied the sun in its annual movement. now it is found advancing in front of the sun to a certain limited distance, and now it is lagging to an equal extent behind the sun. [fig. 1. ptolemy's planetary scheme.] these movements were wholly incompatible with the supposition that the journeys of venus were described by a single motion of the kind regarded as perfect. it was obvious that the movement was connected in some strange manner with the revolution of the sun, and here was the ingenious method by which ptolemy sought to render account of it. imagine a fixed arm to extend from the earth to the sun, as shown in the accompanying figure (fig. 1), then this arm will move round uniformly, in consequence of the sun's movement. at a point p on this arm let a small circle be described. venus is supposed to revolve uniformly in this small circle, while the circle itself is carried round continuously by the movement of the sun. in this way it was possible to account for the chief peculiarities in the movement of venus. it will be seen that, in consequence of the revolution around p, the spectator on the earth will sometimes see venus on one side of the sun, and sometimes on the other side, so that the planet always remains in the sun's vicinity. by properly proportioning the movements, this little contrivance simulated the transitions from the morning star to the evening star. thus the changes of venus could be accounted for by a combination of the "perfect" movement of p in the circle which it described uniformly round the earth, combined with the "perfect" motion of venus in the circle which it described uniformly around the moving centre. in a precisely similar manner ptolemy rendered an explanation of the fitful apparitions of mercury. now just on one side of the sun, and now just on the other, this rarely-seen planet moved like venus on a circle whereof the centre was also carried by the line joining the sun and the earth. the circle, however, in which mercury actually revolved had to be smaller than that of venus, in order to account for the fact that mercury lies always much closer to the sun than the better-known planet. [fig. 2. ptolemy's theory of the movement of mars.] the explanation of the movement of an outer planet like mars could also be deduced from the joint effect of two perfect motions. the changes through which mars goes are, however, so different from the movements of venus that quite a different disposition of the circles is necessary. for consider the facts which characterise the movements of an outer planet such as mars. in the first place, mars accomplishes an entire circuit of the heaven. in this respect, no doubt, it may be said to resemble the sun or the moon. a little attention will, however, show that there are extraordinary irregularities in the movement of the planet. generally speaking, it speeds its way from west to east among the stars, but sometimes the attentive observer will note that the speed with which the planet advances is slackening, and then it will seem to become stationary. some days later the direction of the planet's movement will be reversed, and it will be found moving from the east towards the west. at first it proceeds slowly and then quickens its pace, until a certain speed is attained, which afterwards declines until a second stationary position is reached. after a due pause the original motion from west to east is resumed, and is continued until a similar cycle of changes again commences. such movements as these were obviously quite at variance with any perfect movement in a single circle round the earth. here, again, the geometrical sagacity of ptolemy provided him with the means of representing the apparent movements of mars, and, at the same time, restricting the explanation to those perfect movements which he deemed so essential. in fig. 2 we exhibit ptolemy's theory as to the movement of mars. we have, as before, the earth at the centre, and the sun describing its circular orbit around that centre. the path of mars is to be taken as exterior to that of the sun. we are to suppose that at a point marked m there is a fictitious planet, which revolves around the earth uniformly, in a circle called the deferent. this point m, which is thus animated by a perfect movement, is the centre of a circle which is carried onwards with m, and around the circumference of which mars revolves uniformly. it is easy to show that the combined effect of these two perfect movements is to produce exactly that displacement of mars in the heavens which observation discloses. in the position represented in the figure, mars is obviously pursuing a course which will appear to the observer as a movement from west to east. when, however, the planet gets round to such a position as r, it is then moving from east to west in consequence of its revolution in the moving circle, as indicated by the arrow-head. on the other hand, the whole circle is carried forward in the opposite direction. if the latter movement be less rapid than the former, then we shall have the backward movement of mars on the heavens which it was desired to explain. by a proper adjustment of the relative lengths of these arms the movements of the planet as actually observed could be completely accounted for. the other outer planets with which ptolemy was acquainted, namely, jupiter and saturn, had movements of the same general character as those of mars. ptolemy was equally successful in explaining the movements they performed by the supposition that each planet had perfect rotation in a circle of its own, which circle itself had perfect movement around the earth in the centre. it is somewhat strange that ptolemy did not advance one step further, as by so doing he would have given great simplicity to his system. he might, for instance, have represented the movements of venus equally well by putting the centre of the moving circle at the sun itself, and correspondingly enlarging the circle in which venus revolved. he might, too, have arranged that the several circles which the outer planets traversed should also have had their centres at the sun. the planetary system would then have consisted of an earth fixed at the centre, of a sun revolving uniformly around it, and of a system of planets each describing its own circle around a moving centre placed in the sun. perhaps ptolemy had not thought of this, or perhaps he may have seen arguments against it. this important step was, however, taken by tycho. he considered that all the planets revolved around the sun in circles, and that the sun itself, bearing all these orbits, described a mighty circle around the earth. this point having been reached, only one more step would have been necessary to reach the glorious truths that revealed the structure of the solar system. that last step was taken by copernicus. copernicus [plate: thorn, from an old print.] the quaint town of thorn, on the vistula, was more than two centuries old when copernicus was born there on the 19th of february, 1473. the situation of this town on the frontier between prussia and poland, with the commodious waterway offered by the river, made it a place of considerable trade. a view of the town, as it was at the time of the birth of copernicus, is here given. the walls, with their watch-towers, will be noted, and the strategic importance which the situation of thorn gave to it in the fifteenth century still belongs thereto, so much so that the german government recently constituted the town a fortress of the first class. copernicus, the astronomer, whose discoveries make him the great predecessor of kepler and newton, did not come from a noble family, as certain other early astronomers have done, for his father was a tradesman. chroniclers are, however, careful to tell us that one of his uncles was a bishop. we are not acquainted with any of those details of his childhood or youth which are often of such interest in other cases where men have risen to exalted fame. it would appear that the young nicolaus, for such was his christian name, received his education at home until such time as he was deemed sufficiently advanced to be sent to the university at cracow. the education that he there obtained must have been in those days of a very primitive description, but copernicus seems to have availed himself of it to the utmost. he devoted himself more particularly to the study of medicine, with the view of adopting its practice as the profession of his life. the tendencies of the future astronomer were, however, revealed in the fact that he worked hard at mathematics, and, like one of his illustrious successors, galileo, the practice of the art of painting had for him a very great interest, and in it he obtained some measure of success. by the time he was twenty-seven years old, it would seem that copernicus had given up the notion of becoming a medical practitioner, and had resolved to devote himself to science. he was engaged in teaching mathematics, and appears to have acquired some reputation. his growing fame attracted the notice of his uncle the bishop, at whose suggestion copernicus took holy orders, and he was presently appointed to a canonry in the cathedral of frauenburg, near the mouth of the vistula. to frauenburg, accordingly, this man of varied gifts retired. possessing somewhat of the ascetic spirit, he resolved to devote his life to work of the most serious description. he eschewed all ordinary society, restricting his intimacies to very grave and learned companions, and refusing to engage in conversation of any useless kind. it would seem as if his gifts for painting were condemned as frivolous; at all events, we do not learn that he continued to practise them. in addition to the discharge of his theological duties, his life was occupied partly in ministering medically to the wants of the poor, and partly with his researches in astronomy and mathematics. his equipment in the matter of instruments for the study of the heavens seems to have been of a very meagre description. he arranged apertures in the walls of his house at allenstein, so that he could observe in some fashion the passage of the stars across the meridian. that he possessed some talent for practical mechanics is proved by his construction of a contrivance for raising water from a stream, for the use of the inhabitants of frauenburg. relics of this machine are still to be seen. [plate: copernicus.] the intellectual slumber of the middle ages was destined to be awakened by the revolutionary doctrines of copernicus. it may be noted, as an interesting circumstance, that the time at which he discovered the scheme of the solar system has coincided with a remarkable epoch in the world's history. the great astronomer had just reached manhood at the time when columbus discovered the new world. before the publication of the researches of copernicus, the orthodox scientific creed averred that the earth was stationary, and that the apparent movements of the heavenly bodies were indeed real movements. ptolemy had laid down this doctrine 1,400 years before. in his theory this huge error was associated with so much important truth, and the whole presented such a coherent scheme for the explanation of the heavenly movements, that the ptolemaic theory was not seriously questioned until the great work of copernicus appeared. no doubt others, before copernicus, had from time to time in some vague fashion surmised, with more or less plausibility, that the sun, and not the earth, was the centre about which the system really revolved. it is, however, one thing to state a scientific fact; it is quite another thing to be in possession of the train of reasoning, founded on observation or experiment, by which that fact may be established. pythagoras, it appears, had indeed told his disciples that it was the sun, and not the earth, which was the centre of movement, but it does not seem at all certain that pythagoras had any grounds which science could recognise for the belief which is attributed to him. so far as information is available to us, it would seem that pythagoras associated his scheme of things celestial with a number of preposterous notions in natural philosophy. he may certainly have made a correct statement as to which was the most important body in the solar system, but he certainly did not provide any rational demonstration of the fact. copernicus, by a strict train of reasoning, convinced those who would listen to him that the sun was the centre of the system. it is useful for us to consider the arguments which he urged, and by which he effected that intellectual revolution which is always connected with his name. the first of the great discoveries which copernicus made relates to the rotation of the earth on its axis. that general diurnal movement, by which the stars and all other celestial bodies appear to be carried completely round the heavens once every twenty-four hours, had been accounted for by ptolemy on the supposition that the apparent movements were the real movements. as we have already seen, ptolemy himself felt the extraordinary difficulty involved in the supposition that so stupendous a fabric as the celestial sphere should spin in the way supposed. such movements required that many of the stars should travel with almost inconceivable velocity. copernicus also saw that the daily rising and setting of the heavenly bodies could be accounted for either by the supposition that the celestial sphere moved round and that the earth remained at rest, or by the supposition that the celestial sphere was at rest while the earth turned round in the opposite direction. he weighed the arguments on both sides as ptolemy had done, and, as the result of his deliberations, copernicus came to an opposite conclusion from ptolemy. to copernicus it appeared that the difficulties attending the supposition that the celestial sphere revolved, were vastly greater than those which appeared so weighty to ptolemy as to force him to deny the earth's rotation. copernicus shows clearly how the observed phenomena could be accounted for just as completely by a rotation of the earth as by a rotation of the heavens. he alludes to the fact that, to those on board a vessel which is moving through smooth water, the vessel itself appears to be at rest, while the objects on shore seem to be moving past. if, therefore, the earth were rotating uniformly, we dwellers upon the earth, oblivious of our own movement, would wrongly attribute to the stars the displacement which was actually the consequence of our own motion. copernicus saw the futility of the arguments by which ptolemy had endeavoured to demonstrate that a revolution of the earth was impossible. it was plain to him that there was nothing whatever to warrant refusal to believe in the rotation of the earth. in his clear-sightedness on this matter we have specially to admire the sagacity of copernicus as a natural philosopher. it had been urged that, if the earth moved round, its motion would not be imparted to the air, and that therefore the earth would be uninhabitable by the terrific winds which would be the result of our being carried through the air. copernicus convinced himself that this deduction was preposterous. he proved that the air must accompany the earth, just as his coat remains round him, notwithstanding the fact that he is walking down the street. in this way he was able to show that all a priori objections to the earth's movements were absurd, and therefore he was able to compare together the plausibilities of the two rival schemes for explaining the diurnal movement. [plate: frauenburg, from an old print.] once the issue had been placed in this form, the result could not be long in doubt. here is the question: which is it more likely--that the earth, like a grain of sand at the centre of a mighty globe, should turn round once in twenty-four hours, or that the whole of that vast globe should complete a rotation in the opposite direction in the same time? obviously, the former is far the more simple supposition. but the case is really much stronger than this. ptolemy had supposed that all the stars were attached to the surface of a sphere. he had no ground whatever for this supposition, except that otherwise it would have been well-nigh impossible to have devised a scheme by which the rotation of the heavens around a fixed earth could have been arranged. copernicus, however, with the just instinct of a philosopher, considered that the celestial sphere, however convenient from a geometrical point of view, as a means of representing apparent phenomena, could not actually have a material existence. in the first place, the existence of a material celestial sphere would require that all the myriad stars should be at exactly the same distances from the earth. of course, no one will say that this or any other arbitrary disposition of the stars is actually impossible, but as there was no conceivable physical reason why the distances of all the stars from the earth should be identical, it seemed in the very highest degree improbable that the stars should be so placed. doubtless, also, copernicus felt a considerable difficulty as to the nature of the materials from which ptolemy's wonderful sphere was to be constructed. nor could a philosopher of his penetration have failed to observe that, unless that sphere were infinitely large, there must have been space outside it, a consideration which would open up other difficult questions. whether infinite or not, it was obvious that the celestial sphere must have a diameter at least many thousands of times as great as that of the earth. from these considerations copernicus deduced the important fact that the stars and the other celestial bodies must all be vast objects. he was thus enabled to put the question in such a form that it could hardly receive any answer but the correct one. which is it more rational to suppose, that the earth should turn round on its axis once in twenty-four hours, or that thousands of mighty stars should circle round the earth in the same time, many of them having to describe circles many thousands of times greater in circumference than the circuit of the earth at the equator? the obvious answer pressed upon copernicus with so much force that he was compelled to reject ptolemy's theory of the stationary earth, and to attribute the diurnal rotation of the heavens to the revolution of the earth on its axis. once this tremendous step had been taken, the great difficulties which beset the monstrous conception of the celestial sphere vanished, for the stars need no longer be regarded as situated at equal distances from the earth. copernicus saw that they might lie at the most varied degrees of remoteness, some being hundreds or thousands of times farther away than others. the complicated structure of the celestial sphere as a material object disappeared altogether; it remained only as a geometrical conception, whereon we find it convenient to indicate the places of the stars. once the copernican doctrine had been fully set forth, it was impossible for anyone, who had both the inclination and the capacity to understand it, to withhold acceptance of its truth. the doctrine of a stationary earth had gone for ever. copernicus having established a theory of the celestial movements which deliberately set aside the stability of the earth, it seemed natural that he should inquire whether the doctrine of a moving earth might not remove the difficulties presented in other celestial phenomena. it had been universally admitted that the earth lay unsupported in space. copernicus had further shown that it possessed a movement of rotation. its want of stability being thus recognised, it seemed reasonable to suppose that the earth might also have some other kinds of movements as well. in this, copernicus essayed to solve a problem far more difficult than that which had hitherto occupied his attention. it was a comparatively easy task to show how the diurnal rising and setting could be accounted for by the rotation of the earth. it was a much more difficult undertaking to demonstrate that the planetary movements, which ptolemy had represented with so much success, could be completely explained by the supposition that each of those planets revolved uniformly round the sun, and that the earth was also a planet, accomplishing a complete circuit of the sun once in the course of a year. [plate: explanation of planetary movements.] it would be impossible in a sketch like the present to enter into any detail as to the geometrical propositions on which this beautiful investigation of copernicus depended. we can only mention a few of the leading principles. it may be laid down in general that, if an observer is in movement, he will, if unconscious of the fact, attribute to the fixed objects around him a movement equal and opposite to that which he actually possesses. a passenger on a canal-boat sees the objects on the banks apparently moving backward with a speed equal to that by which he is himself advancing forwards. by an application of this principle, we can account for all the phenomena of the movements of the planets, which ptolemy had so ingeniously represented by his circles. let us take, for instance, the most characteristic feature in the irregularities of the outer planets. we have already remarked that mars, though generally advancing from west to east among the stars, occasionally pauses, retraces his steps for awhile, again pauses, and then resumes his ordinary onward progress. copernicus showed clearly how this effect was produced by the real motion of the earth, combined with the real motion of mars. in the adjoining figure we represent a portion of the circular tracks in which the earth and mars move in accordance with the copernican doctrine. i show particularly the case where the earth comes directly between the planet and the sun, because it is on such occasions that the retrograde movement (for so this backward movement of mars is termed) is at its highest. mars is then advancing in the direction shown by the arrow-head, and the earth is also advancing in the same direction. we, on the earth, however, being unconscious of our own motion, attribute, by the principle i have already explained, an equal and opposite motion to mars. the visible effect upon the planet is, that mars has two movements, a real onward movement in one direction, and an apparent movement in the opposite direction. if it so happened that the earth was moving with the same speed as mars, then the apparent movement would exactly neutralise the real movement, and mars would seem to be at rest relatively to the surrounding stars. under the actual circumstances represented, however, the earth is moving faster than mars, and the consequence is, that the apparent movement of the planet backwards exceeds the real movement forwards, the net result being an apparent retrograde movement. with consummate skill, copernicus showed how the applications of the same principles could account for the characteristic movements of the planets. his reasoning in due time bore down all opposition. the supreme importance of the earth in the system vanished. it had now merely to take rank as one of the planets. the same great astronomer now, for the first time, rendered something like a rational account of the changes of the seasons. nor did certain of the more obscure astronomical phenomena escape his attention. he delayed publishing his wonderful discoveries to the world until he was quite an old man. he had a well-founded apprehension of the storm of opposition which they would arouse. however, he yielded at last to the entreaties of his friends, and his book was sent to the press. but ere it made its appearance to the world, copernicus was seized by mortal illness. a copy of the book was brought to him on may 23, 1543. we are told that he was able to see it and to touch it, but no more, and he died a few hours afterwards. he was buried in that cathedral of frauenburg, with which his life had been so closely associated. tycho brahe. the most picturesque figure in the history of astronomy is undoubtedly that of the famous old danish astronomer whose name stands at the head of this chapter. tycho brahe was alike notable for his astronomical genius and for the extraordinary vehemence of a character which was by no means perfect. his romantic career as a philosopher, and his taste for splendour as a danish noble, his ardent friendships and his furious quarrels, make him an ideal subject for a biographer, while the magnificent astronomical work which he accomplished, has given him imperishable fame. the history of tycho brahe has been admirably told by dr. dreyer, the accomplished astronomer who now directs the observatory at armagh, though himself a countryman of tycho. every student of the career of the great dane must necessarily look on dr. dreyer's work as the chief authority on the subject. tycho sprang from an illustrious stock. his family had flourished for centuries, both in sweden and in denmark, where his descendants are to be met with at the present day. the astronomer's father was a privy councillor, and having filled important positions in the danish government, he was ultimately promoted to be governor of helsingborg castle, where he spent the last years of his life. his illustrious son tycho was born in 1546, and was the second child and eldest boy in a family of ten. it appears that otto, the father of tycho, had a brother named george, who was childless. george, however, desired to adopt a boy on whom he could lavish his affection and to whom he could bequeath his wealth. a somewhat singular arrangement was accordingly entered into by the brothers at the time when otto was married. it was agreed that the first son who might be born to otto should be forthwith handed over by the parents to george to be reared and adopted by him. in due time little tycho appeared, and was immediately claimed by george in pursuance of the compact. but it was not unnatural that the parental instinct, which had been dormant when the agreement was made, should here interpose. tycho's father and mother receded from the bargain, and refused to part with their son. george thought he was badly treated. however, he took no violent steps until a year later, when a brother was born to tycho. the uncle then felt no scruple in asserting what he believed to be his rights by the simple process of stealing the first-born nephew, which the original bargain had promised him. after a little time it would seem that the parents acquiesced in the loss, and thus it was in uncle george's home that the future astronomer passed his childhood. when we read that tycho was no more than thirteen years old at the time he entered the university of copenhagen, it might be at first supposed that even in his boyish years he must have exhibited some of those remarkable talents with which he was afterwards to astonish the world. such an inference should not, however, be drawn. the fact is that in those days it was customary for students to enter the universities at a much earlier age than is now the case. not, indeed, that the boys of thirteen knew more then than the boys of thirteen know now. but the education imparted in the universities at that time was of a much more rudimentary kind than that which we understand by university education at present. in illustration of this dr. dreyer tells us how, in the university of wittenberg, one of the professors, in his opening address, was accustomed to point out that even the processes of multiplication and division in arithmetic might be learned by any student who possessed the necessary diligence. it was the wish and the intention of his uncle that tycho's education should be specially directed to those branches of rhetoric and philosophy which were then supposed to be a necessary preparation for the career of a statesman. tycho, however, speedily made it plain to his teachers that though he was an ardent student, yet the things which interested him were the movements of the heavenly bodies and not the subtleties of metaphysics. [plate: tycho brahe.] on the 21st october, 1560, an eclipse of the sun occurred, which was partially visible at copenhagen. tycho, boy though he was, took the utmost interest in this event. his ardour and astonishment in connection with the circumstance were chiefly excited by the fact that the time of the occurrence of the phenomenon could be predicted with so much accuracy. urged by his desire to understand the matter thoroughly, tycho sought to procure some book which might explain what he so greatly wanted to know. in those days books of any kind were but few and scarce, and scientific books were especially unattainable. it so happened, however, that a latin version of ptolemy's astronomical works had appeared a few years before the eclipse took place, and tycho managed to buy a copy of this book, which was then the chief authority on celestial matters. young as the boy astronomer was, he studied hard, although perhaps not always successfully, to understand ptolemy, and to this day his copy of the great work, copiously annotated and marked by the schoolboy hand, is preserved as one of the chief treasures in the library of the university at prague. after tycho had studied for about three years at the university of copenhagen, his uncle thought it would be better to send him, as was usual in those days, to complete his education by a course of study in some foreign university. the uncle cherished the hope that in this way the attention of the young astronomer might be withdrawn from the study of the stars and directed in what appeared to him a more useful way. indeed, to the wise heads of those days, the pursuit of natural science seemed so much waste of good time which might otherwise be devoted to logic or rhetoric or some other branch of study more in vogue at that time. to assist in this attempt to wean tycho from his scientific tastes, his uncle chose as a tutor to accompany him an intelligent and upright young man named vedel, who was four years senior to his pupil, and accordingly, in 1562, we find the pair taking up their abode at the university of leipzig. the tutor, however, soon found that he had undertaken a most hopeless task. he could not succeed in imbuing tycho with the slightest taste for the study of the law or the other branches of knowledge which were then thought so desirable. the stars, and nothing but the stars, engrossed the attention of his pupil. we are told that all the money he could obtain was spent secretly in buying astronomical books and instruments. he learned the name of the stars from a little globe, which he kept hidden from vedel, and only ventured to use during the latter's absence. no little friction was at first caused by all this, but in after years a fast and enduring friendship grew up between tycho and his tutor, each of whom learned to respect and to love the other. before tycho was seventeen he had commenced the difficult task of calculating the movements of the planets and the places which they occupied on the sky from time to time. he was not a little surprised to find that the actual positions of the planets differed very widely from those which were assigned to them by calculations from the best existing works of astronomers. with the insight of genius he saw that the only true method of investigating the movements of the heavenly bodies would be to carry on a protracted series of measurements of their places. this, which now seems to us so obvious, was then entirely new doctrine. tycho at once commenced regular observations in such fashion as he could. his first instrument was, indeed, a very primitive one, consisting of a simple pair of compasses, which he used in this way. he placed his eye at the hinge, and then opened the legs of the compass so that one leg pointed to one star and the other leg to the other star. the compass was then brought down to a divided circle, by which means the number of degrees in the apparent angular distance of the two stars was determined. his next advance in instrumental equipment was to provide himself with the contrivance known as the "cross-staff," which he used to observe the stars whenever opportunity offered. it must, of course, be remembered that in those days there were no telescopes. in the absence of optical aid, such as lenses afford the modern observers, astronomers had to rely on mechanical appliances alone to measure the places of the stars. of such appliances, perhaps the most ingenious was one known before tycho's time, which we have represented in the adjoining figure. [plate: tycho's cross staff.] let us suppose that it be desired to measure the angle between two stars, then if the angle be not too large it can be determined in the following manner. let the rod ab be divided into inches and parts of an inch, and let another rod, cd, slide up and down along ab in such a way that the two always remain perpendicular to each other. "sights," like those on a rifle, are placed at a and c, and there is a pin at d. it will easily be seen that, by sliding the movable bar along the fixed one, it must always be possible when the stars are not too far apart to bring the sights into such positions that one star can be seen along dc and the other along da. this having been accomplished, the length from a to the cross-bar is read off on the scale, and then, by means of a table previously prepared, the value of the required angular distance is obtained. if the angle between the two stars were greater than it would be possible to measure in the way already described, then there was a provision by which the pin at d might be moved along cd into some other position, so as to bring the angular distance of the stars within the range of the instrument. [plate: tycho's "new star" sextant of 1572. (the arms, of walnut wood, are about 5 1/2 ft. long.)] no doubt the cross-staff is a very primitive contrivance, but when handled by one so skilful as tycho it afforded results of considerable accuracy. i would recommend any reader who may have a taste for such pursuits to construct a cross-staff for himself, and see what measurements he can accomplish with its aid. to employ this little instrument tycho had to evade the vigilance of his conscientious tutor, who felt it his duty to interdict all such occupations as being a frivolous waste of time. it was when vedel was asleep that tycho managed to escape with his cross staff and measure the places of the heavenly bodies. even at this early age tycho used to conduct his observations on those thoroughly sound principles which lie at the foundation of all accurate modern astronomy. recognising the inevitable errors of workmanship in his little instrument, he ascertained their amount and allowed for their influence on the results which he deduced. this principle, employed by the boy with his cross-staff in 1564, is employed at the present day by the astronomer royal at greenwich with the most superb instruments that the skill of modern opticians has been able to construct. [plate: tycho's trigonic sextant. (the arms, ab and ac, are about 5 1/2 ft. long.)] after the death of his uncle, when tycho was nineteen years of age, it appears that the young philosopher was no longer interfered with in so far as the line which his studies were to take was concerned. always of a somewhat restless temperament, we now find that he shifted his abode to the university of rostock, where he speedily made himself notable in connection with an eclipse of the moon on 28th october, 1566. like every other astronomer of those days, tycho had always associated astronomy with astrology. he considered that the phenomena of the heavenly bodies always had some significance in connection with human affairs. tycho was also a poet, and in the united capacity of poet, astrologer, and astronomer, he posted up some verses in the college at rostock announcing that the lunar eclipse was a prognostication of the death of the great turkish sultan, whose mighty deeds at that time filled men's minds. presently news did arrive of the death of the sultan, and tycho was accordingly triumphant; but a little later it appeared that the decease had taken place before the eclipse, a circumstance which caused many a laugh at tycho's expense. [plate: tycho's astronomic sextant. (made of steel: the arms, ab, ac, measure 4 ft.) plate: tycho's equatorial armillary. (the meridian circle, e b c a d, made of solid steel, is nearly 6 ft. in diameter.)] tycho being of a somewhat turbulent disposition, it appears that, while at the university of rostock, he had a serious quarrel with another danish nobleman. we are not told for certain what was the cause of the dispute. it does not, however, seem to have had any more romantic origin than a difference of opinion as to which of them knew the more mathematics. they fought, as perhaps it was becoming for two astronomers to fight, under the canopy of heaven in utter darkness at the dead of night, and the duel was honourably terminated when a slice was taken off tycho's nose by the insinuating sword of his antagonist. for the repair of this injury the ingenuity of the great instrument-maker was here again useful, and he made a substitute for his nose "with a composition of gold and silver." the imitation was so good that it is declared to have been quite equal to the original. dr. lodge, however, pointedly observes that it does not appear whether this remark was made by a friend or an enemy. [plate: the great augsburg quadrant. (built of heart of oak; the radii about 19 ft.) plate: tycho's "new scheme of the terrestrial system," 1577.] the next few years tycho spent in various places ardently pursuing somewhat varied branches of scientific study. at one time we hear of him assisting an astronomical alderman, in the ancient city of augsburg, to erect a tremendous wooden machine--a quadrant of 19-feet radius--to be used in observing the heavens. at another time we learn that the king of denmark had recognised the talents of his illustrious subject, and promised to confer on him a pleasant sinecure in the shape of a canonry, which would assist him with the means for indulging his scientific pursuits. again we are told that tycho is pursuing experiments in chemistry with the greatest energy, nor is this so incompatible as might at first be thought with his devotion to astronomy. in those early days of knowledge the different sciences seemed bound together by mysterious bonds. alchemists and astrologers taught that the several planets were correlated in some mysterious manner with the several metals. it was, therefore hardly surprising that tycho should have included a study of the properties of the metals in the programme of his astronomical work. [plate: uraniborg and its grounds. plate: ground-plan of the observatory.] an event, however, occurred in 1572 which stimulated tycho's astronomical labours, and started him on his life's work. on the 11th of november in that year, he was returning home to supper after a day's work in his laboratory, when he happened to lift his face to the sky, and there he beheld a brilliant new star. it was in the constellation of cassiopeia, and occupied a position in which there had certainly been no bright star visible when his attention had last been directed to that part of the heavens. such a phenomenon was so startling that he found it hard to trust the evidence of his senses. he thought he must be the subject of some hallucination. he therefore called to the servants who were accompanying him, and asked them whether they, too, could see a brilliant object in the direction in which he pointed. they certainly could, and thus he became convinced that this marvellous object was no mere creation of the fancy, but a veritable celestial body--a new star of surpassing splendour which had suddenly burst forth. in these days of careful scrutiny of the heavens, we are accustomed to the occasional outbreak of new stars. it is not, however, believed that any new star which has ever appeared has displayed the same phenomenal brilliance as was exhibited by the star of 1572. this object has a value in astronomy far greater than it might at first appear. it is true, in one sense, that tycho discovered the new star, but it is equally true, in a different sense, that it was the new star which discovered tycho. had it not been for this opportune apparition, it is quite possible that tycho might have found a career in some direction less beneficial to science than that which he ultimately pursued. [plate: the observatory of uraniborg, island of hven.] when he reached his home on this memorable evening, tycho immediately applied his great quadrant to the measurement of the place of the new star. his observations were specially directed to the determination of the distance of the object. he rightly conjectured that if it were very much nearer to us than the stars in its vicinity, the distance of the brilliant body might be determined in a short time by the apparent changes in its distance from the surrounding points. it was speedily demonstrated that the new star could not be as near as the moon, by the simple fact that its apparent place, as compared with the stars in its neighbourhood, was not appreciably altered when it was observed below the pole, and again above the pole at an interval of twelve hours. such observations were possible, inasmuch as the star was bright enough to be seen in full daylight. tycho thus showed conclusively that the body was so remote that the diameter of the earth bore an insignificant ratio to the star's distance. his success in this respect is the more noteworthy when we find that many other observers, who studied the same object, came to the erroneous conclusion that the new star was quite as near as the moon, or even much nearer. in fact, it may be said, that with regard to this object tycho discovered everything which could possibly have been discovered in the days before telescopes were invented. he not only proved that the star's distance was too great for measurement, but he showed that it had no proper motion on the heavens. he recorded the successive changes in its brightness from week to week, as well as the fluctuations in hue with which the alterations in lustre were accompanied. it seems, nowadays, strange to find that such thoroughly scientific observations of the new star as those which tycho made, possessed, even in the eyes of the great astronomer himself, a profound astrological significance. we learn from dr. dreyer that, in tycho's opinion, "the star was at first like venus and jupiter, and its effects will therefore, first, be pleasant; but as it then became like mars, there will next come a period of wars, seditions, captivity, and death of princes, and destruction of cities, together with dryness and fiery meteors in the air, pestilence, and venomous snakes. lastly, the star became like saturn, and thus will finally come a time of want, death, imprisonment, and all kinds of sad things!" ideas of this kind were, however, universally entertained. it seemed, indeed, obvious to learned men of that period that such an apparition must forebode startling events. one of the chief theories then held was, that just as the star of bethlehem announced the first coming of christ, so the second coming, and the end of the world, was heralded by the new star of 1572. the researches of tycho on this object were the occasion of his first appearance as an author. the publication of his book was however, for some time delayed by the urgent remonstrances of his friends, who thought it was beneath the dignity of a nobleman to condescend to write a book. happily, tycho determined to brave the opinion of his order; the book appeared, and was the first of a series of great astronomical productions from the same pen. [plate: effigy on tycho's tomb at prague.] the fame of the noble dane being now widespread, the king of denmark entreated him to return to his native country, and to deliver a course of lectures on astronomy in the university of copenhagen. with some reluctance he consented, and his introductory oration has been preserved. he dwells, in fervent language, upon the beauty and the interest of the celestial phenomena. he points out the imperative necessity of continuous and systematic observation of the heavenly bodies in order to extend our knowledge. he appeals to the practical utility of the science, for what civilised nation could exist without having the means of measuring time? he sets forth how the study of these beautiful objects "exalts the mind from earthly and trivial things to heavenly ones;" and then he winds up by assuring them that "a special use of astronomy is that it enables us to draw conclusions from the movements in the celestial regions as to human fate." an interesting event, which occurred in 1572, distracted tycho's attention from astronomical matters. he fell in love. the young girl on whom his affections were set appears to have sprung from humble origin. here again his august family friends sought to dissuade him from a match they thought unsuitable for a nobleman. but tycho never gave way in anything. it is suggested that he did not seek a wife among the highborn dames of his own rank from the dread that the demands of a fashionable lady would make too great an inroad on the time that he wished to devote to science. at all events, tycho's union seems to have been a happy one, and he had a large family of children; none of whom, however, inherited their father's talents. [plate: tycho's mural quadrant picture, uraniborg.] tycho had many scientific friends in germany, among whom his work was held in high esteem. the treatment that he there met with seemed to him so much more encouraging than that which he received in denmark that he formed the notion of emigrating to basle and making it his permanent abode. a whisper of this intention was conveyed to the large-hearted king of denmark, frederick ii. he wisely realised how great would be the fame which would accrue to his realm if he could induce tycho to remain within danish territory and carry on there the great work of his life. a resolution to make a splendid proposal to tycho was immediately formed. a noble youth was forthwith despatched as a messenger, and ordered to travel day and night until he reached tycho, whom he was to summon to the king. the astronomer was in bed on the morning of 11th february, 1576, when the message was delivered. tycho, of course, set off at once and had an audience of the king at copenhagen. the astronomer explained that what he wanted was the means to pursue his studies unmolested, whereupon the king offered him the island of hven, in the sound near elsinore. there he would enjoy all the seclusion that he could desire. the king further promised that he would provide the funds necessary for building a house and for founding the greatest observatory that had ever yet been reared for the study of the heavens. after due deliberation and consultation with his friends, tycho accepted the king's offer. he was forthwith granted a pension, and a deed was drawn up formally assigning the island of hven to his use all the days of his life. the foundation of the famous castle of uraniborg was laid on 30th august, 1576. the ceremony was a formal and imposing one, in accordance with tycho's ideas of splendour. a party of scientific friends had assembled, and the time had been chosen so that the heavenly bodies were auspiciously placed. libations of costly wines were poured forth, and the stone was placed with due solemnity. the picturesque character of this wonderful temple for the study of the stars may be seen in the figures with which this chapter is illustrated. one of the most remarkable instruments that has ever been employed in studying the heavens was the mural quadrant which tycho erected in one of the apartments of uraniborg. by its means the altitudes of the celestial bodies could be observed with much greater accuracy than had been previously attainable. this wonderful contrivance is represented on the preceding page. it will be observed that the walls of the room are adorned by pictures with a lavishness of decoration not usually to be found in scientific establishments. a few years later, when the fame of the observatory at hven became more widely spread, a number of young men flocked to tycho to study under his direction. he therefore built another observatory for their use in which the instruments were placed in subterranean rooms of which only the roofs appeared above the ground. there was a wonderful poetical inscription over the entrance to this underground observatory, expressing the astonishment of urania at finding, even in the interior of the earth, a cavern devoted to the study of the heavens. tycho was indeed always fond of versifying, and he lost no opportunity of indulging this taste whenever an occasion presented itself. around the walls of the subterranean observatory were the pictures of eight astronomers, each with a suitable inscription--one of these of course represented tycho himself, and beneath were written words to the effect that posterity should judge of his work. the eighth picture depicted an astronomer who has not yet come into existence. tychonides was his name, and the inscription presses the modest hope that when he does appear he will be worthy of his great predecessor. the vast expenses incurred in the erection and the maintenance of this strange establishment were defrayed by a succession of grants from the royal purse. for twenty years tycho laboured hard at uraniborg in the pursuit of science. his work mainly consisted in the determination of the places of the moon, the planets, and the stars on the celestial sphere. the extraordinary pains taken by tycho to have his observations as accurate as his instruments would permit, have justly entitled him to the admiration of all succeeding astronomers. his island home provided the means of recreation as well as a place for work. he was surrounded by his family, troops of friends were not wanting, and a pet dwarf seems to have been an inmate of his curious residence. by way of change from his astronomical labours he used frequently to work with his students in his chemical laboratory. it is not indeed known what particular problems in chemistry occupied his attention. we are told, however, that he engaged largely in the production of medicines, and as these appear to have been dispensed gratuitously there was no lack of patients. tycho's imperious and grasping character frequently brought him into difficulties, which seem to have increased with his advancing years. he had ill-treated one of his tenants on hven, and an adverse decision by the courts seems to have greatly exasperated the astronomer. serious changes also took place in his relations to the court at copenhagen. when the young king was crowned in 1596, he reversed the policy of his predecessor with reference to hven. the liberal allowances to tycho were one after another withdrawn, and finally even his pension was stopped. tycho accordingly abandoned hven in a tumult of rage and mortification. a few years later we find him in bohemia a prematurely aged man, and he died on the 24th october, 1601. galileo. among the ranks of the great astronomers it would be difficult to find one whose life presents more interesting features and remarkable vicissitudes than does that of galileo. we may consider him as the patient investigator and brilliant discoverer. we may consider him in his private relations, especially to his daughter, sister maria celeste, a woman of very remarkable character; and we have also the pathetic drama at the close of galileo's life, when the philosopher drew down upon himself the thunders of the inquisition. the materials for the sketch of this astonishing man are sufficiently abundant. we make special use in this place of those charming letters which his daughter wrote to him from her convent home. more than a hundred of these have been preserved, and it may well be doubted whether any more beautiful and touching series of letters addressed to a parent by a dearly loved child have ever been written. an admirable account of this correspondence is contained in a little book entitled "the private life of galileo," published anonymously by messrs. macmillan in 1870, and i have been much indebted to the author of that volume for many of the facts contained in this chapter. galileo was born at pisa, on 18th february, 1564. he was the eldest son of vincenzo de' bonajuti de' galilei, a florentine noble. notwithstanding his illustrious birth and descent, it would seem that the home in which the great philosopher's childhood was spent was an impoverished one. it was obvious at least that the young galileo would have to be provided with some profession by which he might earn a livelihood. from his father he derived both by inheritance and by precept a keen taste for music, and it appears that he became an excellent performer on the lute. he was also endowed with considerable artistic power, which he cultivated diligently. indeed, it would seem that for some time the future astronomer entertained the idea of devoting himself to painting as a profession. his father, however, decided that he should study medicine. accordingly, we find that when galileo was seventeen years of age, and had added a knowledge of greek and latin to his acquaintance with the fine arts, he was duly entered at the university of pisa. here the young philosopher obtained some inkling of mathematics, whereupon he became so much interested in this branch of science, that he begged to be allowed to study geometry. in compliance with his request, his father permitted a tutor to be engaged for this purpose; but he did so with reluctance, fearing that the attention of the young student might thus be withdrawn from that medical work which was regarded as his primary occupation. the event speedily proved that these anxieties were not without some justification. the propositions of euclid proved so engrossing to galileo that it was thought wise to avoid further distraction by terminating the mathematical tutor's engagement. but it was too late for the desired end to be attained. galileo had now made such progress that he was able to continue his geometrical studies by himself. presently he advanced to that famous 47th proposition which won his lively admiration, and on he went until he had mastered the six books of euclid, which was a considerable achievement for those days. the diligence and brilliance of the young student at pisa did not, however, bring him much credit with the university authorities. in those days the doctrines of aristotle were regarded as the embodiment of all human wisdom in natural science as well as in everything else. it was regarded as the duty of every student to learn aristotle off by heart, and any disposition to doubt or even to question the doctrines of the venerated teacher was regarded as intolerable presumption. but young galileo had the audacity to think for himself about the laws of nature. he would not take any assertion of fact on the authority of aristotle when he had the means of questioning nature directly as to its truth or falsehood. his teachers thus came to regard him as a somewhat misguided youth, though they could not but respect the unflagging industry with which he amassed all the knowledge he could acquire. [plate: galileo's pendulum.] we are so accustomed to the use of pendulums in our clocks that perhaps we do not often realise that the introduction of this method of regulating time-pieces was really a notable invention worthy the fame of the great astronomer to whom it was due. it appears that sitting one day in the cathedral of pisa, galileo's attention became concentrated on the swinging of a chandelier which hung from the ceiling. it struck him as a significant point, that whether the arc through which the pendulum oscillated was a long one or a short one, the time occupied in each vibration was sensibly the same. this suggested to the thoughtful observer that a pendulum would afford the means by which a time-keeper might be controlled, and accordingly galileo constructed for the first time a clock on this principle. the immediate object sought in this apparatus was to provide a means of aiding physicians in counting the pulses of their patients. the talents of galileo having at length extorted due recognition from the authorities, he was appointed, at the age of twenty-five, professor of mathematics at the university of pisa. then came the time when he felt himself strong enough to throw down the gauntlet to the adherents of the old philosophy. as a necessary part of his doctrine on the movement of bodies aristotle had asserted that the time occupied by a stone in falling depends upon its weight, so that the heavier the stone the less time would it require to fall from a certain height to the earth. it might have been thought that a statement so easily confuted by the simplest experiments could never have maintained its position in any accepted scheme of philosophy. but aristotle had said it, and to anyone who ventured to express a doubt the ready sneer was forthcoming, "do you think yourself a cleverer man than aristotle?" galileo determined to demonstrate in the most emphatic manner the absurdity of a doctrine which had for centuries received the sanction of the learned. the summit of the leaning tower of pisa offered a highly dramatic site for the great experiment. the youthful professor let fall from the overhanging top a large heavy body and a small light body simultaneously. according to aristotle the large body ought to have reached the ground much sooner than the small one, but such was found not to be the case. in the sight of a large concourse of people the simple fact was demonstrated that the two bodies fell side by side, and reached the ground at the same time. thus the first great step was taken in the overthrow of that preposterous system of unquestioning adhesion to dogma, which had impeded the development of the knowledge of nature for nearly two thousand years. this revolutionary attitude towards the ancient beliefs was not calculated to render galileo's relations with the university authorities harmonious. he had also the misfortune to make enemies in other quarters. don giovanni de medici, who was then the governor of the port of leghorn, had designed some contrivance by which he proposed to pump out a dock. but galileo showed up the absurdity of this enterprise in such an aggressive manner that don giovanni took mortal offence, nor was he mollified when the truths of galileo's criticisms were abundantly verified by the total failure of his ridiculous invention. in various ways galileo was made to feel his position at pisa so unpleasant that he was at length compelled to abandon his chair in the university. the active exertions of his friends, of whom galileo was so fortunate as to have had throughout his life an abundant supply, then secured his election to the professorship of mathematics at padua, whither he went in 1592. [plate: portrait of galileo.] it was in this new position that galileo entered on that marvellous career of investigation which was destined to revolutionize science. the zeal with which he discharged his professorial duties was indeed of the most unremitting character. he speedily drew such crowds to listen to his discourses on natural philosophy that his lecture-room was filled to overflowing. he also received many private pupils in his house for special instruction. every moment that could be spared from these labours was devoted to his private study and to his incessant experiments. like many another philosopher who has greatly extended our knowledge of nature, galileo had a remarkable aptitude for the invention of instruments designed for philosophical research. to facilitate his practical work, we find that in 1599 he had engaged a skilled workman who was to live in his house, and thus be constantly at hand to try the devices for ever springing from galileo's fertile brain. among the earliest of his inventions appears to have been the thermometer, which he constructed in 1602. no doubt this apparatus in its primitive form differed in some respects from the contrivance we call by the same name. galileo at first employed water as the agent, by the expansion of which the temperature was to be measured. he afterwards saw the advantage of using spirits for the same purpose. it was not until about half a century later that mercury came to be recognised as the liquid most generally suitable for the thermometer. the time was now approaching when galileo was to make that mighty step in the advancement of human knowledge which followed on the application of the telescope to astronomy. as to how his idea of such an instrument originated, we had best let him tell us in his own words. the passage is given in a letter which he writes to his brother-in-law, landucci. "i write now because i have a piece of news for you, though whether you will be glad or sorry to hear it i cannot say; for i have now no hope of returning to my own country, though the occurrence which has destroyed that hope has had results both useful and honourable. you must know, then, that two months ago there was a report spread here that in flanders some one had presented to count maurice of nassau a glass manufactured in such a way as to make distant objects appear very near, so that a man at the distance of two miles could be clearly seen. this seemed to me so marvellous that i began to think about it. as it appeared to me to have a foundation in the theory of perspective, i set about contriving how to make it, and at length i found out, and have succeeded so well that the one i have made is far superior to the dutch telescope. it was reported in venice that i had made one, and a week since i was commanded to show it to his serenity and to all the members of the senate, to their infinite amazement. many gentlemen and senators, even the oldest, have ascended at various times the highest bell-towers in venice to spy out ships at sea making sail for the mouth of the harbour, and have seen them clearly, though without my telescope they would have been invisible for more than two hours. the effect of this instrument is to show an object at a distance of say fifty miles, as if it were but five miles." the remarkable properties of the telescope at once commanded universal attention among intellectual men. galileo received applications from several quarters for his new instrument, of which it would seem that he manufactured a large number to be distributed as gifts to various illustrious personages. but it was reserved for galileo himself to make that application of the instrument to the celestial bodies by which its peculiar powers were to inaugurate the new era in astronomy. the first discovery that was made in this direction appears to have been connected with the number of the stars. galileo saw to his amazement that through his little tube he could count ten times as many stars in the sky as his unaided eye could detect. here was, indeed, a surprise. we are now so familiar with the elementary facts of astronomy that it is not always easy to realise how the heavens were interpreted by the observers in those ages prior to the invention of the telescope. we can hardly, indeed, suppose that galileo, like the majority of those who ever thought of such matters, entertained the erroneous belief that the stars were on the surface of a sphere at equal distances from the observer. no one would be likely to have retained his belief in such a doctrine when he saw how the number of visible stars could be increased tenfold by means of galileo's telescope. it would have been almost impossible to refuse to draw the inference that the stars thus brought into view were still more remote objects which the telescope was able to reveal, just in the same way as it showed certain ships to the astonished venetians, when at the time these ships were beyond the reach of unaided vision. galileo's celestial discoveries now succeeded each other rapidly. that beautiful milky way, which has for ages been the object of admiration to all lovers of nature, never disclosed its true nature to the eye of man till the astronomer of padua turned on it his magic tube. the splendid zone of silvery light was then displayed as star-dust scattered over the black background of the sky. it was observed that though the individual stars were too small to be seen severally without optical aid, yet such was their incredible number that the celestial radiance produced that luminosity with which every stargazer was so familiar. but the greatest discovery made by the telescope in these early days, perhaps, indeed, the greatest discovery that the telescope has ever accomplished, was the detection of the system of four satellites revolving around the great planet jupiter. this phenomenon was so wholly unexpected by galileo that, at first, he could hardly believe his eyes. however, the reality of the existence of a system of four moons attending the great planet was soon established beyond all question. numbers of great personages crowded to galileo to see for themselves this beautiful miniature representing the sun with its system of revolving planets. of course there were, as usual, a few incredulous people who refused to believe the assertion that four more moving bodies had to be added to the planetary system. they scoffed at the notion; they said the satellites may have been in the telescope, but that they were not in the sky. one sceptical philosopher is reported to have affirmed, that even if he saw the moons of jupiter himself he would not believe in them, as their existence was contrary to the principles of common-sense! there can be no doubt that a special significance attached to the new discovery at this particular epoch in the history of science. it must be remembered that in those days the doctrine of copernicus, declaring that the sun, and not the earth, was the centre of the system, that the earth revolved on its axis once a day, and that it described a mighty circle round the sun once a year, had only recently been promulgated. this new view of the scheme of nature had been encountered with the most furious opposition. it may possibly have been that galileo himself had not felt quite confident in the soundness of the copernican theory, prior to the discovery of the satellites of jupiter. but when a picture was there exhibited in which a number of relatively small globes were shown to be revolving around a single large globe in the centre, it seemed impossible not to feel that the beautiful spectacle so displayed was an emblem of the relations of the planets to the sun. it was thus made manifest to galileo that the copernican theory of the planetary system must be the true one. the momentous import of this opinion upon the future welfare of the great philosopher will presently appear. it would seem that galileo regarded his residence at padua as a state of undesirable exile from his beloved tuscany. he had always a yearning to go back to his own country and at last the desired opportunity presented itself. for now that galileo's fame had become so great, the grand duke of tuscany desired to have the philosopher resident at florence, in the belief that he would shed lustre on the duke's dominions. overtures were accordingly made to galileo, and the consequence was that in 1616 we find him residing at florence, bearing the title of mathematician and philosopher to the grand duke. two daughters, polissena and virginia, and one son, vincenzo, had been born to galileo in padua. it was the custom in those days that as soon as the daughter of an italian gentleman had grown up, her future career was somewhat summarily decided. either a husband was to be forthwith sought out, or she was to enter the convent with the object of taking the veil as a professed nun. it was arranged that the two daughters of galileo, while still scarcely more than children, should both enter the franciscan convent of st. matthew, at arcetri. the elder daughter polissena, took the name of sister maria celeste, while virginia became sister arcangela. the latter seems to have been always delicate and subject to prolonged melancholy, and she is of but little account in the narrative of the life of galileo. but sister maria celeste, though never leaving the convent, managed to preserve a close intimacy with her beloved father. this was maintained only partly by galileo's visits, which were very irregular and were, indeed, often suspended for long intervals. but his letters to this daughter were evidently frequent and affectionate, especially in the latter part of his life. most unfortunately, however, all his letters have been lost. there are grounds for believing that they were deliberately destroyed when galileo was seized by the inquisition, lest they should have been used as evidence against him, or lest they should have compromised the convent where they were received. but sister maria celeste's letters to her father have happily been preserved, and most touching these letters are. we can hardly read them without thinking how the sweet and gentle nun would have shrunk from the idea of their publication. her loving little notes to her "dearest lord and father," as she used affectionately to call galileo, were almost invariably accompanied by some gift, trifling it may be, but always the best the poor nun had to bestow. the tender grace of these endearing communications was all the more precious to him from the fact that the rest of galileo's relatives were of quite a worthless description. he always acknowledged the ties of his kindred in the most generous way, but their follies and their vices, their selfishness and their importunities, were an incessant source of annoyance to him, almost to the last day of his life. on 19th december, 1625, sister maria celeste writes:-"i send two baked pears for these days of vigil. but as the greatest treat of all, i send you a rose, which ought to please you extremely, seeing what a rarity it is at this season; and with the rose you must accept its thorns, which represent the bitter passion of our lord, whilst the green leaves represent the hope we may entertain that through the same sacred passion we, having passed through the darkness of the short winter of our mortal life, may attain to the brightness and felicity of an eternal spring in heaven." when the wife and children of galileo's shiftless brother came to take up their abode in the philosopher's home, sister maria celeste feels glad to think that her father has now some one who, however imperfectly, may fulfil the duty of looking after him. a graceful note on christmas eve accompanies her little gifts. she hopes that-"in these holy days the peace of god may rest on him and all the house. the largest collar and sleeves i mean for albertino, the other two for the two younger boys, the little dog for baby, and the cakes for everybody, except the spice-cakes, which are for you. accept the good-will which would readily do much more." the extraordinary forbearance with which galileo continually placed his time, his purse, and his influence at the service of those who had repeatedly proved themselves utterly unworthy of his countenance, is thus commented on by the good nun.-"now it seems to me, dearest lord and father, that your lordship is walking in the right path, since you take hold of every occasion that presents itself to shower continual benefits on those who only repay you with ingratitude. this is an action which is all the more virtuous and perfect as it is the more difficult." when the plague was raging in the neighbourhood, the loving daughter's solicitude is thus shown:-"i send you two pots of electuary as a preventive against the plague. the one without the label consists of dried figs, walnuts, rue, and salt, mixed together with honey. a piece of the size of a walnut to be taken in the morning, fasting, with a little greek wine." the plague increasing still more, sister maria celeste obtained with much difficulty, a small quantity of a renowned liqueur, made by abbess ursula, an exceptionally saintly nun. this she sends to her father with the words:-"i pray your lordship to have faith in this remedy. for if you have so much faith in my poor miserable prayers, much more may you have in those of such a holy person; indeed, through her merits you may feel sure of escaping all danger from the plague." whether galileo took the remedy we do not know, but at all events he escaped the plague. [plate: the villa arcetri. galileo's residence, where milton visited him.] from galileo's new home in florence the telescope was again directed to the skies, and again did astounding discoveries reward the astronomer's labours. the great success which he had met with in studying jupiter naturally led galileo to look at saturn. here he saw a spectacle which was sufficiently amazing, though he failed to interpret it accurately. it was quite manifest that saturn did not exhibit a simple circular disc like jupiter, or like mars. it seemed to galileo as if the planet consisted of three bodies, a large globe in the centre, and a smaller one on each side. the enigmatical nature of the discovery led galileo to announce it in an enigmatical manner. he published a string of letters which, when duly transposed, made up a sentence which affirmed that the planet saturn was threefold. of course we now know that this remarkable appearance of the planet was due to the two projecting portions of the ring. with the feeble power of galileo's telescope, these seemed merely like small globes or appendages to the large central body. the last of galileo's great astronomical discoveries related to the libration of the moon. i think that the detection of this phenomenon shows his acuteness of observation more remarkably than does any one of his other achievements with the telescope. it is well known that the moon constantly keeps the same face turned towards the earth. when, however, careful measurements have been made with regard to the spots and marks on the lunar surface, it is found that there is a slight periodic variation which permits us to see now a little to the east or to the west, now a little to the north or to the south of the average lunar disc. but the circumstances which make the career of galileo so especially interesting from the biographer's point of view, are hardly so much the triumphs that he won as the sufferings that he endured. the sufferings and the triumphs were, however, closely connected, and it is fitting that we should give due consideration to what was perhaps the greatest drama in the history of science. on the appearance of the immortal work of copernicus, in which it was taught that the earth rotated on its axis, and that the earth, like the other planets, revolved round the sun, orthodoxy stood aghast. the holy roman church submitted this treatise, which bore the name "de revolutionibus orbium coelestium," to the congregation of the index. after due examination it was condemned as heretical in 1615. galileo was suspected, on no doubt excellent grounds, of entertaining the objectionable views of copernicus. he was accordingly privately summoned before cardinal bellarmine on 26th february 1616, and duly admonished that he was on no account to teach or to defend the obnoxious doctrines. galileo was much distressed by this intimation. he felt it a serious matter to be deprived of the privilege of discoursing with his friends about the copernican system, and of instructing his disciples in the principles of the great theory of whose truth he was perfectly convinced. it pained him, however, still more to think, devout catholic as he was, that such suspicions of his fervent allegiance to his church should ever have existed, as were implied by the words and monitions of cardinal bellarmine. in 1616, galileo had an interview with pope paul v., who received the great astronomer very graciously, and walked up and down with him in conversation for three-quarters of an hour. galileo complained to his holiness of the attempts made by his enemies to embarrass him with the authorities of the church, but the pope bade him be comforted. his holiness had himself no doubts of galileo's orthodoxy, and he assured him that the congregation of the index should give galileo no further trouble so long as paul v. was in the chair of st. peter. on the death of paul v. in 1623, maffeo barberini was elected pope, as urban viii. this new pope, while a cardinal, had been an intimate friend of galileo's, and had indeed written latin verses in praise of the great astronomer and his discoveries. it was therefore not unnatural for galileo to think that the time had arrived when, with the use of due circumspection, he might continue his studies and his writings, without fear of incurring the displeasure of the church. indeed, in 1624, one of galileo's friends writing from rome, urges galileo to visit the city again, and added that-"under the auspices of this most excellent, learned, and benignant pontiff, science must flourish. your arrival will be welcome to his holiness. he asked me if you were coming, and when, and in short, he seems to love and esteem you more than ever." the visit was duly paid, and when galileo returned to florence, the pope wrote a letter from which the following is an extract, commanding the philosopher to the good offices of the young ferdinand, who had shortly before succeeded his father in the grand duchy of tuscany. "we find in galileo not only literary distinction, but also the love of piety, and he is also strong in those qualities by which the pontifical good-will is easily obtained. and now, when he has been brought to this city to congratulate us on our elevation, we have very lovingly embraced him; nor can we suffer him to return to the country whither your liberality calls him, without an ample provision of pontifical love. and that you may know how dear he is to us, we have willed to give him this honourable testimonial of virtue and piety. and we further signify that every benefit which you shall confer upon him, imitating or even surpassing your father's liberality, will conduce to our gratification." the favourable reception which had been accorded to him by pope urban viii. seems to have led galileo to expect that there might be some corresponding change in the attitude of the papal authorities on the great question of the stability of the earth. he accordingly proceeded with the preparation of the chief work of his life, "the dialogue of the two systems." it was submitted for inspection by the constituted authorities. the pope himself thought that, if a few conditions which he laid down were duly complied with, there could be no objection to the publication of the work. in the first place, the title of the book was to be so carefully worded as to show plainly that the copernican doctrine was merely to be regarded as an hypothesis, and not as a scientific fact. galileo was also instructed to conclude the book with special arguments which had been supplied by the pope himself, and which appeared to his holiness to be quite conclusive against the new doctrine of copernicus. formal leave for the publication of the dialogue was then given to galileo by the inquisitor general, and it was accordingly sent to the press. it might be thought that the anxieties of the astronomer about his book would then have terminated. as a matter of fact, they had not yet seriously begun. riccardi, the master of the sacred palace, having suddenly had some further misgivings, sent to galileo for the manuscript while the work was at the printer's, in order that the doctrine it implied might be once again examined. apparently, riccardi had come to the conclusion that he had not given the matter sufficient attention, when the authority to go to press had been first and, perhaps, hastily given. considerable delay in the issue of the book was the result of these further deliberations. at last, however, in june, 1632, galileo's great work, "the dialogue of the two systems," was produced for the instruction of the world, though the occasion was fraught with ruin to the immortal author. [plate: facsimile sketch of lunar surface by galileo.] the book, on its publication, was received and read with the greatest avidity. but presently the master of the sacred palace found reason to regret that he had given his consent to its appearance. he accordingly issued a peremptory order to sequestrate every copy in italy. this sudden change in the papal attitude towards galileo formed the subject of a strong remonstrance addressed to the roman authorities by the grand duke of tuscany. the pope himself seemed to have become impressed all at once with the belief that the work contained matter of an heretical description. the general interpretation put upon the book seems to have shown the authorities that they had mistaken its true tendency, notwithstanding the fact that it had been examined again and again by theologians deputed for the duty. to the communication from the grand duke the pope returned answer, that he had decided to submit the book to a congregation of "learned, grave, and saintly men," who would weigh every word in it. the views of his holiness personally on the subject were expressed in his belief that the dialogue contained the most perverse matter that could come into a reader's hands. the master of the sacred palace was greatly blamed by the authorities for having given his sanction to its issue. he pleaded that the book had not been printed in the precise terms of the original manuscript which had been submitted to him. it was also alleged that galileo had not adhered to his promise of inserting properly the arguments which the pope himself had given in support of the old and orthodox view. one of these had, no doubt, been introduced, but, so far from mending galileo's case, it had made matters really look worse for the poor philosopher. the pope's argument had been put into the mouth of one of the characters in the dialogue named "simplicio." galileo's enemies maintained that by adopting such a method for the expression of his holiness's opinion, galileo had intended to hold the pope himself up to ridicule. galileo's friends maintained that nothing could have been farther from his intention. it seems, however, highly probable that the suspicions thus aroused had something to say to the sudden change of front on the part of the papal authorities. on 1st october, 1632, galileo received an order to appear before the inquisition at rome on the grave charge of heresy. galileo, of course, expressed his submission, but pleaded for a respite from compliance with the summons, on the ground of his advanced age and his failing health. the pope was, however, inexorable; he said that he had warned galileo of his danger while he was still his friend. the command could not be disobeyed. galileo might perform the journey as slowly as he pleased, but it was imperatively necessary for him to set forth and at once. on 20th january, 1633, galileo started on his weary journey to rome, in compliance with this peremptory summons. on 13th february he was received as the guest of niccolini, the tuscan ambassador, who had acted as his wise and ever-kind friend throughout the whole affair. it seemed plain that the holy office were inclined to treat galileo with as much clemency and consideration as was consistent with the determination that the case against him should be proceeded with to the end. the pope intimated that in consequence of his respect for the grand duke of tuscany he should permit galileo to enjoy the privilege, quite unprecedented for a prisoner charged with heresy, of remaining as an inmate in the ambassador's house. he ought, strictly, to have been placed in the dungeons of the inquisition. when the examination of the accused had actually commenced, galileo was confined, not, indeed, in the dungeons, but in comfortable rooms at the holy office. by the judicious and conciliatory language of submission which niccolini had urged galileo to use before the inquisitors, they were so far satisfied that they interceded with the pope for his release. during the remainder of the trial galileo was accordingly permitted to go back to the ambassador's, where he was most heartily welcomed. sister maria celeste, evidently thinking this meant that the whole case was at an end, thus expresses herself:-"the joy that your last dear letter brought me, and the having to read it over and over to the nuns, who made quite a jubilee on hearing its contents, put me into such an excited state that at last i got a severe attack of headache." in his defence galileo urged that he had already been acquitted in 1616 by cardinal bellarmine, when a charge of heresy was brought against him, and he contended that anything he might now have done, was no more than he had done on the preceding occasion, when the orthodoxy of his doctrines received solemn confirmation. the inquisition seemed certainly inclined to clemency, but the pope was not satisfied. galileo was accordingly summoned again on the 21st june. he was to be threatened with torture if he did not forthwith give satisfactory explanations as to the reasons which led him to write the dialogue. in this proceeding the pope assured the tuscan ambassador that he was treating galileo with the utmost consideration possible in consequence of his esteem and regard for the grand duke, whose servant galileo was. it was, however, necessary that some exemplary punishment be meted out to the astronomer, inasmuch as by the publication of the dialogue he had distinctly disobeyed the injunction of silence laid upon him by the decree of 1616. nor was it admissible for galileo to plead that his book had been sanctioned by the master of the sacred college, to whose inspection it had been again and again submitted. it was held, that if the master of the sacred college had been unaware of the solemn warning the philosopher had already received sixteen years previously, it was the duty of galileo to have drawn his attention to that fact. on the 22nd june, 1633, galileo was led to the great hall of the inquisition, and compelled to kneel before the cardinals there assembled and hear his sentence. in a long document, most elaborately drawn up, it is definitely charged against galileo that, in publishing the dialogue, he committed the essentially grave error of treating the doctrine of the earth's motion as open to discussion. galileo knew, so the document affirmed, that the church had emphatically pronounced this notion to be contrary to holy writ, and that for him to consider a doctrine so stigmatized as having any shadow of probability in its favour was an act of disrespect to the authority of the church which could not be overlooked. it was also charged against galileo that in his dialogue he has put the strongest arguments into the mouth, not of those who supported the orthodox doctrine, but of those who held the theory as to the earth's motion which the church had so deliberately condemned. after due consideration of the defence made by the prisoner, it was thereupon decreed that he had rendered himself vehemently suspected of heresy by the holy office, and in consequence had incurred all the censures and penalties of the sacred canons, and other decrees promulgated against such persons. the graver portion of these punishments would be remitted, if galileo would solemnly repudiate the heresies referred to by an abjuration to be pronounced by him in the terms laid down. at the same time it was necessary to mark, in some emphatic manner, the serious offence which had been committed, so that it might serve both as a punishment to galileo and as a warning to others. it was accordingly decreed that he should be condemned to imprisonment in the holy office during the pleasure of the papal authorities, and that he should recite once a week for three years the seven penitential psalms. then followed that ever-memorable scene in the great hall of the inquisition, in which the aged and infirm galileo, the inventor of the telescope and the famous astronomer, knelt down to abjure before the most eminent and reverend lords cardinal, inquisitors general throughout the christian republic against heretical depravity. with his hands on the gospels, galileo was made to curse and detest the false opinion that the sun was the centre of the universe and immovable, and that the earth was not the centre of the same, and that it moved. he swore that for the future he will never say nor write such things as may bring him under suspicion, and that if he does so he submits to all the pains and penalties of the sacred canons. this abjuration was subsequently read in florence before galileo's disciples, who had been specially summoned to attend. it has been noted that neither on the first occasion, in 1616, nor on the second in 1633, did the reigning pope sign the decrees concerning galileo. the contention has accordingly been made that paul v. and urban viii. are both alike vindicated from any technical responsibility for the attitude of the romish church towards the copernican doctrines. the significance of this circumstance has been commented on in connection with the doctrine of the infallibility of the pope. we can judge of the anxiety felt by sister maria celeste about her beloved father during these terrible trials. the wife of the ambassador niccolini, galileo's steadfast friend, most kindly wrote to give the nun whatever quieting assurances the case would permit. there is a renewed flow of these touching epistles from the daughter to her father. thus she sends word-"the news of your fresh trouble has pierced my soul with grief all the more that it came quite unexpectedly." and again, on hearing that he had been permitted to leave rome, she writes-"i wish i could describe the rejoicing of all the mothers and sisters on hearing of your happy arrival at siena. it was indeed most extraordinary. on hearing the news the mother abbess and many of the nuns ran to me, embracing me and weeping for joy and tenderness." the sentence of imprisonment was at first interpreted leniently by the pope. galileo was allowed to reside in qualified durance in the archbishop's house at siena. evidently the greatest pain that he endured arose from the forced separation from that daughter, whom he had at last learned to love with an affection almost comparable with that she bore to him. she had often told him that she never had any pleasure equal to that with which she rendered any service to her father. to her joy, she discovers that she can relieve him from the task of reciting the seven penitential psalms which had been imposed as a penance:-"i began to do this a while ago," she writes, "and it gives me much pleasure. first, because i am persuaded that prayer in obedience to holy church must be efficacious; secondly, in order to save you the trouble of remembering it. if i had been able to do more, most willingly would i have entered a straiter prison than the one i live in now, if by so doing i could have set you at liberty." [plate: crest of galileo's family.] sister maria celeste was gradually failing in health, but the great privilege was accorded to her of being able once again to embrace her beloved lord and master. galileo had, in fact, been permitted to return to his old home; but on the very day when he heard of his daughter's death came the final decree directing him to remain in his own house in perpetual solitude. amid the advancing infirmities of age, the isolation from friends, and the loss of his daughter, galileo once again sought consolation in hard work. he commenced his famous dialogue on motion. gradually, however, his sight began to fail, and blindness was at last added to his other troubles. on january 2nd, 1638, he writes to diodati:-"alas, your dear friend and servant, galileo, has been for the last month perfectly blind, so that this heaven, this earth, this universe which i by my marvellous discoveries and clear demonstrations have enlarged a hundred thousand times beyond the belief of the wise men of bygone ages, henceforward is for me shrunk into such a small space as is filled by my own bodily sensations." but the end was approaching--the great philosopher, was attacked by low fever, from which he died on the 8th january, 1643. kepler. while the illustrious astronomer, tycho brahe, lay on his death-bed, he had an interview which must ever rank as one of the important incidents in the history of science. the life of tycho had been passed, as we have seen, in the accumulation of vast stores of careful observations of the positions of the heavenly bodies. it was not given to him to deduce from his splendid work the results to which they were destined to lead. it was reserved for another astronomer to distil, so to speak, from the volumes in which tycho's figures were recorded, the great truths of the universe which those figures contained. tycho felt that his work required an interpreter, and he recognised in the genius of a young man with whom he was acquainted the agent by whom the world was to be taught some of the great truths of nature. to the bedside of the great danish astronomer the youthful philosopher was summoned, and with his last breath tycho besought of him to spare no labour in the performance of those calculations, by which alone the secrets of the movements of the heavens could be revealed. the solemn trust thus imposed was duly accepted, and the man who accepted it bore the immortal name of kepler. kepler was born on the 27th december, 1571, at weil, in the duchy of wurtemberg. it would seem that the circumstances of his childhood must have been singularly unhappy. his father, sprung from a well-connected family, was but a shiftless and idle adventurer; nor was the great astronomer much more fortunate in his other parent. his mother was an ignorant and ill-tempered woman; indeed, the ill-assorted union came to an abrupt end through the desertion of the wife by her husband when their eldest son john, the hero of our present sketch, was eighteen years old. the childhood of this lad, destined for such fame, was still further embittered by the circumstance that when he was four years old he had a severe attack of small-pox. not only was his eyesight permanently injured, but even his constitution appears to have been much weakened by this terrible malady. it seems, however, that the bodily infirmities of young john kepler were the immediate cause of his attention being directed to the pursuit of knowledge. had the boy been fitted like other boys for ordinary manual work, there can be hardly any doubt that to manual work his life must have been devoted. but, though his body was feeble, he soon gave indications of the possession of considerable mental power. it was accordingly thought that a suitable sphere for his talents might be found in the church which, in those days, was almost the only profession that afforded an opening for an intellectual career. we thus find that by the time john kepler was seventeen years old he had attained a sufficient standard of knowledge to entitle him to admission on the foundation of the university at tubingen. in the course of his studies at this institution he seems to have divided his attention equally between astronomy and divinity. it not unfrequently happens that when a man has attained considerable proficiency in two branches of knowledge he is not able to see very clearly in which of the two pursuits his true vocation lies. his friends and onlookers are often able to judge more wisely than he himself can do as to which of the two lines it would be better for him to pursue. this incapacity for perceiving the path in which greatness awaited him, existed in the case of kepler. personally, he inclined to enter the ministry, in which a promising career seemed open to him. he yielded, however, to friends, who evidently knew him better than he knew himself, and accepted in 1594, the important professorship of astronomy which had been offered to him in the university of gratz. it is difficult for us in these modern days to realise the somewhat extraordinary duties which were expected from an astronomical professor in the sixteenth century. he was, of course, required to employ his knowledge of the heavens in the prediction of eclipses, and of the movements of the heavenly bodies generally. this seems reasonable enough; but what we are not prepared to accept is the obligation which lay on the astronomers to predict the fates of nations and the destinies of individuals. it must be remembered that it was the almost universal belief in those days, that all the celestial spheres revolved in some mysterious fashion around the earth, which appeared by far the most important body in the universe. it was imagined that the sun, the moon, and the stars indicated, in the vicissitudes of their movements, the careers of nations and of individuals. such being the generally accepted notion, it seemed to follow that a professor who was charged with the duty of expounding the movements of the heavenly bodies must necessarily be looked to for the purpose of deciphering the celestial decrees regarding the fate of man which the heavenly luminaries were designed to announce. kepler threw himself with characteristic ardour into even this fantastic phase of the labours of the astronomical professor; he diligently studied the rules of astrology, which the fancies of antiquity had compiled. believing sincerely as he did in the connection between the aspect of the stars and the state of human affairs, he even thought that he perceived, in the events of his own life, a corroboration of the doctrine which affirmed the influence of the planets upon the fate of individuals. [plate: kepler's system of regular solids.] but quite independently of astrology there seem to have been many other delusions current among the philosophers of kepler's time. it is now almost incomprehensible how the ablest men of a few centuries ago should have entertained such preposterous notions, as they did, with respect to the system of the universe. as an instance of what is here referred to, we may cite the extraordinary notion which, under the designation of a discovery, first brought kepler into fame. geometers had long known that there were five, but no more than five, regular solid figures. there is, for instance, the cube with six sides, which is, of course, the most familiar of these solids. besides the cube there are other figures of four, eight, twelve, and twenty sides respectively. it also happened that there were five planets, but no more than five, known to the ancients, namely, mercury, venus, mars, jupiter, and saturn. to kepler's lively imaginations this coincidence suggested the idea that the five regular solids corresponded to the five planets, and a number of fancied numerical relations were adduced on the subject. the absurdity of this doctrine is obvious enough, especially when we observe that, as is now well known, there are two large planets, and a host of small planets, over and above the magical number of the regular solids. in kepler's time, however, this doctrine was so far from being regarded as absurd, that its announcement was hailed as a great intellectual triumph. kepler was at once regarded with favour. it seems, indeed, to have been the circumstance which brought him into correspondence with tycho brahe. by its means also he became known to galileo. the career of a scientific professor in those early days appears generally to have been marked by rather more striking vicissitudes than usually befall a professor in a modern university. kepler was a protestant, and as such he had been appointed to his professorship at gratz. a change, however, having taken place in the religious belief entertained by the ruling powers of the university, the protestant professors were expelled. it seems that special influence having been exerted in kepler's case on account of his exceptional eminence, he was recalled to gratz and reinstated in the tenure of his chair. but his pupils had vanished, so that the great astronomer was glad to accept a post offered him by tycho brahe in the observatory which the latter had recently established near prague. on tycho's death, which occurred soon after, an opening presented itself which gave kepler the opportunity his genius demanded. he was appointed to succeed tycho in the position of imperial mathematician. but a far more important point, both for kepler and for science, was that to him was confided the use of tycho's observations. it was, indeed, by the discussion of tycho's results that kepler was enabled to make the discoveries which form such an important part of astronomical history. kepler must also be remembered as one of the first great astronomers who ever had the privilege of viewing celestial bodies through a telescope. it was in 1610 that he first held in his hands one of those little instruments which had been so recently applied to the heavens by galileo. it should, however, be borne in mind that the epoch-making achievements of kepler did not arise from any telescopic observations that he made, or, indeed, that any one else made. they were all elaborately deduced from tycho's measurements of the positions of the planets, obtained with his great instruments, which were unprovided with telescopic assistance. to realise the tremendous advance which science received from kepler's great work, it is to be understood that all the astronomers who laboured before him at the difficult subject of the celestial motions, took it for granted that the planets must revolve in circles. if it did not appear that a planet moved in a fixed circle, then the ready answer was provided by ptolemy's theory that the circle in which the planet did move was itself in motion, so that its centre described another circle. when kepler had before him that wonderful series of observations of the planet, mars, which had been accumulated by the extraordinary skill of tycho, he proved, after much labour, that the movements of the planet refused to be represented in a circular form. nor would it do to suppose that mars revolved in one circle, the centre of which revolved in another circle. on no such supposition could the movements of the planets be made to tally with those which tycho had actually observed. this led to the astonishing discovery of the true form of a planet's orbit. for the first time in the history of astronomy the principle was laid down that the movement of a planet could not be represented by a circle, nor even by combinations of circles, but that it could be represented by an elliptic path. in this path the sun is situated at one of those two points in the ellipse which are known as its foci. [plate: kepler.] very simple apparatus is needed for the drawing of one of those ellipses which kepler has shown to possess such astonishing astronomical significance. two pins are stuck through a sheet of paper on a board, the point of a pencil is inserted in a loop of string which passes over the pins, and as the pencil is moved round in such a way as to keep the string stretched, that beautiful curve known as the ellipse is delineated, while the positions of the pins indicate the two foci of the curve. if the length of the loop of string is unchanged then the nearer the pins are together, the greater will be the resemblance between the ellipse and the circle, whereas the more the pins are separated the more elongated does the ellipse become. the orbit of a great planet is, in general, one of those ellipses which approaches a nearly circular form. it fortunately happens, however, that the orbit of mars makes a wider departure from the circular form than any of the other important planets. it is, doubtless, to this circumstance that we must attribute the astonishing success of kepler in detecting the true shape of a planetary orbit. tycho's observations would not have been sufficiently accurate to have exhibited the elliptic nature of a planetary orbit which, like that of venus, differed very little from a circle. the more we ponder on this memorable achievement the more striking will it appear. it must be remembered that in these days we know of the physical necessity which requires that a planet shall revolve in an ellipse and not in any other curve. but kepler had no such knowledge. even to the last hour of his life he remained in ignorance of the existence of any natural cause which ordained that planets should follow those particular curves which geometers know so well. kepler's assignment of the ellipse as the true form of the planetary orbit is to be regarded as a brilliant guess, the truth of which tycho's observations enabled him to verify. kepler also succeeded in pointing out the law according to which the velocity of a planet at different points of its path could be accurately specified. here, again, we have to admire the sagacity with which this marvellously acute astronomer guessed the deep truth of nature. in this case also he was quite unprovided with any reason for expecting from physical principles that such a law as he discovered must be obeyed. it is quite true that kepler had some slight knowledge of the existence of what we now know as gravitation. he had even enunciated the remarkable doctrine that the ebb and flow of the tide must be attributed to the attraction of the moon on the waters of the earth. he does not, however, appear to have had any anticipation of those wonderful discoveries which newton was destined to make a little later, in which he demonstrated that the laws detected by kepler's marvellous acumen were necessary consequences of the principle of universal gravitation. [plate: symbolical representation of the planetary system.] to appreciate the relations of kepler and tycho it is necessary to note the very different way in which these illustrious astronomers viewed the system of the heavens. it should be observed that copernicus had already expounded the true system, which located the sun at the centre of the planetary system. but in the days of tycho brahe this doctrine had not as yet commanded universal assent. in fact, the great observer himself did not accept the new views of copernicus. it appeared to tycho that the earth not only appeared to be the centre of things celestial, but that it actually was the centre. it is, indeed, not a little remarkable that a student of the heavens so accurate as tycho should have deliberately rejected the copernican doctrine in favour of the system which now seems so preposterous. throughout his great career, tycho steadily observed the places of the sun, the moon, and the planets, and as steadily maintained that all those bodies revolved around the earth fixed in the centre. kepler, however, had the advantage of belonging to the new school. he utilised the observations of tycho in developing the great copernican theory whose teaching tycho stoutly resisted. perhaps a chapter in modern science may illustrate the intellectual relation of these great men. the revolution produced by copernicus in the doctrine of the heavens has often been likened to the revolution which the darwinian theory produced in the views held by biologists as to life on this earth. the darwinian theory did not at first command universal assent even among those naturalists whose lives had been devoted with the greatest success to the study of organisms. take, for instance, that great naturalist, professor owen, by whose labours vast extension has been given to our knowledge of the fossil animals which dwelt on the earth in past ages. now, though owens researches were intimately connected with the great labours of darwin, and afforded the latter material for his epoch-making generalization, yet owen deliberately refused to accept the new doctrines. like tycho, he kept on rigidly accumulating his facts under the influence of a set of ideas as to the origin of living forms which are now universally admitted to be erroneous. if, therefore, we liken darwin to copernicus, and owen to tycho, we may liken the biologists of the present day to kepler, who interpreted the results of accurate observation upon sound theoretical principles. in reading the works of kepler in the light of our modern knowledge we are often struck by the extent to which his perception of the sublimest truths in nature was associated with the most extravagant errors and absurdities. but, of course, it must be remembered that he wrote in an age in which even the rudiments of science, as we now understand it, were almost entirely unknown. it may well be doubted whether any joy experienced by mortals is more genuine than that which rewards the successful searcher after natural truths. every science-worker, be his efforts ever so humble, will be able to sympathise with the enthusiastic delight of kepler when at last, after years of toil, the glorious light broke forth, and that which he considered to be the greatest of his astonishing laws first dawned upon him. kepler rightly judged that the number of days which a planet required to perform its voyage round the sun must be connected in some manner with the distance from the planet to the sun; that is to say, with the radius of the planet's orbit, inasmuch as we may for our present object regard the planet's orbit as circular. here, again, in his search for the unknown law, kepler had no accurate dynamical principles to guide his steps. of course, we now know not only what the connection between the planet's distance and the planet's periodic time actually is, but we also know that it is a necessary consequence of the law of universal gravitation. kepler, it is true, was not without certain surmises on the subject, but they were of the most fanciful description. his notions of the planets, accurate as they were in certain important respects, were mixed up with vague ideas as to the properties of metals and the geometrical relations of the regular solids. above all, his reasoning was penetrated by the supposed astrological influences of the stars and their significant relation to human fate. under the influence of such a farrago of notions, kepler resolved to make all sorts of trials in his search for the connection between the distance of a planet from the sun and the time in which the revolution of that planet was accomplished. it was quite easily demonstrated that the greater the distance of the planet from the sun the longer was the time required for its journey. it might have been thought that the time would be directly proportional to the distance. it was, however, easy to show that this supposition did not agree with the fact. finding that this simple relation would not do, kepler undertook a vast series of calculations to find out the true method of expressing the connection. at last, after many vain attempts, he found, to his indescribable joy, that the square of the time in which a planet revolves around the sun was proportional to the cube of the average distance of the planet from that body. the extraordinary way in which kepler's views on celestial matters were associated with the wildest speculations, is well illustrated in the work in which he propounded his splendid discovery just referred to. the announcement of the law connecting the distances of the planets from the sun with their periodic times, was then mixed up with a preposterous conception about the properties of the different planets. they were supposed to be associated with some profound music of the spheres inaudible to human ears, and performed only for the benefit of that being whose soul formed the animating spirit of the sun. kepler was also the first astronomer who ever ventured to predict the occurrence of that remarkable phenomenon, the transit of a planet in front of the sun's disc. he published, in 1629, a notice to the curious in things celestial, in which he announced that both of the planets, mercury and venus, were to make a transit across the sun on specified days in the winter of 1631. the transit of mercury was duly observed by gassendi, and the transit of venus also took place, though, as we now know, the circumstances were such that it was not possible for the phenomenon to be witnessed by any european astronomer. in addition to kepler's discoveries already mentioned, with which his name will be for ever associated, his claim on the gratitude of astronomers chiefly depends on the publication of his famous rudolphine tables. in this remarkable work means are provided for finding the places of the planets with far greater accuracy than had previously been attainable. kepler, it must be always remembered, was not an astronomical observer. it was his function to deal with the observations made by tycho, and, from close study and comparison of the results, to work out the movements of the heavenly bodies. it was, in fact, tycho who provided as it were the raw material, while it was the genius of kepler which wrought that material into a beautiful and serviceable form. for more than a century the rudolphine tables were regarded as a standard astronomical work. in these days we are accustomed to find the movements of the heavenly bodies set forth with all desirable exactitude in the nautical almanack, and the similar publication issued by foreign governments. let it be remembered that it was kepler who first imparted the proper impulse in this direction. [plate: the commemoration of the rudolphine tables.] when kepler was twenty-six he married an heiress from styria, who, though only twenty-three years old, had already had some experience in matrimony. her first husband had died; and it was after her second husband had divorced her that she received the addresses of kepler. it will not be surprising to hear that his domestic affairs do not appear to have been particularly happy, and his wife died in 1611. two years later, undeterred by the want of success in his first venture, he sought a second partner, and he evidently determined not to make a mistake this time. indeed, the methodical manner in which he made his choice of the lady to whom he should propose has been duly set forth by him and preserved for our edification. with some self-assurance he asserts that there were no fewer than eleven spinsters desirous of sharing his joys and sorrows. he has carefully estimated and recorded the merits and demerits of each of these would-be brides. the result of his deliberations was that he awarded himself to an orphan girl, destitute even of a portion. success attended his choice, and his second marriage seems to have proved a much more suitable union than his first. he had five children by the first wife and seven by the second. the years of kepler's middle life were sorely distracted by a trouble which, though not uncommon in those days, is one which we find it difficult to realise at the present time. his mother, catherine kepler, had attained undesirable notoriety by the suspicion that she was guilty of witchcraft. years were spent in legal investigations, and it was only after unceasing exertions on the part of the astronomer for upwards of a twelve-month that he was finally able to procure her acquittal and release from prison. it is interesting for us to note that at one time there was a proposal that kepler should forsake his native country and adopt england as a home. it arose in this wise. the great man was distressed throughout the greater part of his life by pecuniary anxieties. finding him in a strait of this description, the english ambassador in venice, sir henry wotton, in the year 1620, besought kepler to come over to england, where he assured him that he would obtain a favourable reception, and where, he was able to add, kepler's great scientific work was already highly esteemed. but his efforts were unavailing; kepler would not leave his own country. he was then forty-nine years of age, and doubtless a home in a foreign land, where people spoke a strange tongue, had not sufficient attraction for him, even when accompanied with the substantial inducements which the ambassador was able to offer. had kepler accepted this invitation, he would, in transferring his home to england, have anticipated the similar change which took place in the career of another great astronomer two centuries later. it will be remembered that herschel, in his younger days, did transfer himself to england, and thus gave to england the imperishable fame of association with his triumphs. the publication of the rudolphine tables of the celestial movements entailed much expense. a considerable part of this was defrayed by the government at venice but the balance occasioned no little trouble and anxiety to kepler. no doubt the authorities of those days were even less willing to spend money on scientific matters than are the governments of more recent times. for several years the imperial treasury was importuned to relieve him from his anxieties. the effects of so much worry, and of the long journeys which were involved, at last broke down kepler's health completely. as we have already mentioned, he had never been strong from infancy, and he finally succumbed to a fever in november, 1630, at the age of fifty-nine. he was interred at st. peter's church at ratisbon. though kepler had not those personal characteristics which have made his great predecessor, tycho brahe, such a romantic figure, yet a picturesque element in kepler's character is not wanting. it was, however, of an intellectual kind. his imagination, as well as his reasoning faculties, always worked together. he was incessantly prompted by the most extraordinary speculations. the great majority of them were in a high degree wild and chimerical, but every now and then one of his fancies struck right to the heart of nature, and an immortal truth was brought to light. i remember visiting the observatory of one of our greatest modern astronomers, and in a large desk he showed me a multitude of photographs which he had attempted but which had not been successful, and then he showed me the few and rare pictures which had succeeded, and by which important truths had been revealed. with a felicity of expression which i have often since thought of, he alluded to the contents of the desk as the "chips." they were useless, but they were necessary incidents in the truly successful work. so it is in all great and good work. even the most skilful man of science pursues many a wrong scent. time after time he goes off on some track that plays him false. the greater the man's genius and intellectual resource, the more numerous will be the ventures which he makes, and the great majority of those ventures are certain to be fruitless. they are in fact, the "chips." in kepler's case the chips were numerous enough. they were of the most extraordinary variety and structure. but every now and then a sublime discovery was made of such a character as to make us regard even the most fantastic of kepler's chips with the greatest veneration and respect. isaac newton. it was just a year after the death of galileo, that an infant came into the world who was christened isaac newton. even the great fame of galileo himself must be relegated to a second place in comparison with that of the philosopher who first expounded the true theory of the universe. isaac newton was born on the 25th of december (old style), 1642, at woolsthorpe, in lincolnshire, about a half-mile from colsterworth, and eight miles south of grantham. his father, mr. isaac newton, had died a few months after his marriage to harriet ayscough, the daughter of mr. james ayscough, of market overton, in rutlandshire. the little isaac was at first so excessively frail and weakly that his life was despaired of. the watchful mother, however, tended her delicate child with such success that he seems to have thriven better than might have been expected from the circumstances of his infancy, and he ultimately acquired a frame strong enough to outlast the ordinary span of human life. for three years they continued to live at woolsthorpe, the widow's means of livelihood being supplemented by the income from another small estate at sewstern, in a neighbouring part of leicestershire. [plate: woolsthorpe manor. showing solar dial made by newton when a boy.] in 1645, mrs. newton took as a second husband the rev. barnabas smith, and on moving to her new home, about a mile from woolsthorpe, she entrusted little isaac to her mother, mrs. ayscough. in due time we find that the boy was sent to the public school at grantham, the name of the master being stokes. for the purpose of being near his work, the embryo philosopher was boarded at the house of mr. clark, an apothecary at grantham. we learn from newton himself that at first he had a very low place in the class lists of the school, and was by no means one of those model school-boys who find favour in the eyes of the school-master by attention to latin grammar. isaac's first incentive to diligent study seems to have been derived from the circumstance that he was severely kicked by one of the boys who was above him in the class. this indignity had the effect of stimulating young newton's activity to such an extent that he not only attained the desired object of passing over the head of the boy who had maltreated him, but continued to rise until he became the head of the school. the play-hours of the great philosopher were devoted to pursuits very different from those of most school-boys. his chief amusement was found in making mechanical toys and various ingenious contrivances. he watched day by day with great interest the workmen engaged in constructing a windmill in the neighbourhood of the school, the result of which was that the boy made a working model of the windmill and of its machinery, which seems to have been much admired, as indicating his aptitude for mechanics. we are told that isaac also indulged in somewhat higher flights of mechanical enterprise. he constructed a carriage, the wheels of which were to be driven by the hands of the occupant, while the first philosophical instrument he made was a clock, which was actuated by water. he also devoted much attention to the construction of paper kites, and his skill in this respect was highly appreciated by his school-fellows. like a true philosopher, even at this stage he experimented on the best methods of attaching the string, and on the proportions which the tail ought to have. he also made lanthorns of paper to provide himself with light as he walked to school in the dark winter mornings. the only love affair in newton's life appears to have commenced while he was still of tender years. the incidents are thus described in brewster's "life of newton," a work to which i am much indebted in this chapter. "in the house where he lodged there were some female inmates, in whose company he appears to have taken much pleasure. one of these, a miss storey, sister to dr. storey, a physician at buckminster, near colsterworth, was two or three years younger than newton and to great personal attractions she seems to have added more than the usual allotment of female talent. the society of this young lady and her companions was always preferred to that of his own school-fellows, and it was one of his most agreeable occupations to construct for them little tables and cupboards, and other utensils for holding their dolls and their trinkets. he had lived nearly six years in the same house with miss storey, and there is reason to believe that their youthful friendship gradually rose to a higher passion; but the smallness of her portion, and the inadequacy of his own fortune, appear to have prevented the consummation of their happiness. miss storey was afterwards twice married, and under the name of mrs. vincent, dr. stukeley visited her at grantham in 1727, at the age of eighty-two, and obtained from her many particulars respecting the early history of our author. newton's esteem for her continued unabated during his life. he regularly visited her when he went to lincolnshire, and never failed to relieve her from little pecuniary difficulties which seem to have beset her family." the schoolboy at grantham was only fourteen years of age when his mother became a widow for the second time. she then returned to the old family home at woolsthorpe, bringing with her the three children of her second marriage. her means appear to have been somewhat scanty, and it was consequently thought necessary to recall isaac from the school. his recently-born industry had been such that he had already made good progress in his studies, and his mother hoped that he would now lay aside his books, and those silent meditations to which, even at this early age, he had become addicted. it was expected that, instead of such pursuits, which were deemed quite useless, the boy would enter busily into the duties of the farm and the details of a country life. but before long it became manifest that the study of nature and the pursuit of knowledge had such a fascination for the youth that he could give little attention to aught else. it was plain that he would make but an indifferent farmer. he greatly preferred experimenting on his water-wheels to looking after labourers, while he found that working at mathematics behind a hedge was much more interesting than chaffering about the price of bullocks in the market place. fortunately for humanity his mother, like a wise woman, determined to let her boy's genius have the scope which it required. he was accordingly sent back to grantham school, with the object of being trained in the knowledge which would fit him for entering the university of cambridge. [plate: trinity college, cambridge. showing newton's rooms; on the leads of the gateway he placed his telescope.] it was the 5th of june, 1660, when isaac newton, a youth of eighteen, was enrolled as an undergraduate of trinity college, cambridge. little did those who sent him there dream that this boy was destined to be the most illustrious student who ever entered the portals of that great seat of learning. little could the youth himself have foreseen that the rooms near the gateway which he occupied would acquire a celebrity from the fact that he dwelt in them, or that the ante-chapel of his college was in good time to be adorned by that noble statue, which is regarded as one of the chief art treasures of cambridge university, both on account of its intrinsic beauty and the fact that it commemorates the fame of her most distinguished alumnus, isaac newton, the immortal astronomer. indeed, his advent at the university seemed to have been by no means auspicious or brilliant. his birth was, as we have seen, comparatively obscure, and though he had already given indication of his capacity for reflecting on philosophical matters, yet he seems to have been but ill-equipped with the routine knowledge which youths are generally expected to take with them to the universities. from the outset of his college career, newton's attention seems to have been mainly directed to mathematics. here he began to give evidence of that marvellous insight into the deep secrets of nature which more than a century later led so dispassionate a judge as laplace to pronounce newton's immortal work as pre-eminent above all the productions of the human intellect. but though newton was one of the very greatest mathematicians that ever lived, he was never a mathematician for the mere sake of mathematics. he employed his mathematics as an instrument for discovering the laws of nature. his industry and genius soon brought him under the notice of the university authorities. it is stated in the university records that he obtained a scholarship in 1664. two years later we find that newton, as well as many residents in the university, had to leave cambridge temporarily on account of the breaking out of the plague. the philosopher retired for a season to his old home at woolsthorpe, and there he remained until he was appointed a fellow of trinity college, cambridge, in 1667. from this time onwards, newton's reputation as a mathematician and as a natural philosopher steadily advanced, so that in 1669, while still but twenty-seven years of age, he was appointed to the distinguished position of lucasian professor of mathematics at cambridge. here he found the opportunity to continue and develop that marvellous career of discovery which formed his life's work. the earliest of newton's great achievements in natural philosophy was his detection of the composite character of light. that a beam of ordinary sunlight is, in fact, a mixture of a very great number of different-coloured lights, is a doctrine now familiar to every one who has the slightest education in physical science. we must, however, remember that this discovery was really a tremendous advance in knowledge at the time when newton announced it. [plate: diagram of a sunbeam.] we here give the little diagram originally drawn by newton, to explain the experiment by which he first learned the composition of light. a sunbeam is admitted into a darkened room through an opening, h, in a shutter. this beam when not interfered with will travel in a straight line to the screen, and there reproduce a bright spot of the same shape as the hole in the shutter. if, however, a prism of glass, a b c, be introduced so that the beam traverse it, then it will be seen at once that the light is deflected from its original track. there is, however, a further and most important change which takes place. the spot of light is not alone removed to another part of the screen, but it becomes spread out into a long band beautifully coloured, and exhibiting the hues of the rainbow. at the top are the violet rays, and then in descending order we have the indigo, blue, green, yellow, orange, and red. the circumstance in this phenomenon which appears to have particularly arrested newton's attention, was the elongation which the luminous spot underwent in consequence of its passage through the prism. when the prism was absent the spot was nearly circular, but when the prism was introduced the spot was about five times as long as it was broad. to ascertain the explanation of this was the first problem to be solved. it seemed natural to suppose that it might be due to the thickness of the glass in the prism which the light traversed, or to the angle of incidence at which the light fell upon the prism. he found, however, upon careful trial, that the phenomenon could not be thus accounted for. it was not until after much patient labour that the true explanation dawned upon him. he discovered that though the beam of white light looks so pure and so simple, yet in reality it is composed of differently coloured lights blended together. these are, of course, indistinguishable in the compound beam, but they are separated or disentangled, so to speak, by the action of the prism. the rays at the blue end of the spectrum are more powerfully deflected by the action of the glass than are the rays at the red end. thus, the rays variously coloured red, orange, yellow, green, blue, indigo, violet, are each conducted to a different part of the screen. in this way the prism has the effect of exhibiting the constitution of the composite beam of light. to us this now seems quite obvious, but newton did not adopt it hastily. with characteristic caution he verified the explanation by many different experiments, all of which confirmed his discovery. one of these may be mentioned. he made a hole in the screen at that part on which the violet rays fell. thus a violet ray was allowed to pass through, all the rest of the light being intercepted, and on this beam so isolated he was able to try further experiments. for instance, when he interposed another prism in its path, he found, as he expected, that it was again deflected, and he measured the amount of the deflection. again he tried the same experiment with one of the red rays from the opposite end of the coloured band. he allowed it to pass through the same aperture in the screen, and he tested the amount by which the second prism was capable of producing deflection. he thus found, as he had expected to find, that the second prism was more efficacious in bending the violet rays than in bending the red rays. thus he confirmed the fact that the various hues of the rainbow were each bent by a prism to a different extent, violet being acted upon the most, and red the least. [plate: isaac newton.] not only did newton decompose a white beam into its constituent colours, but conversely by interposing a second prism with its angle turned upwards, he reunited the different colours, and thus reproduced the original beam of white light. in several other ways also he illustrated his famous proposition, which then seemed so startling, that white light was the result of a mixture of all hues of the rainbow. by combining painters' colours in the right proportion he did not indeed succeed in producing a mixture which would ordinarily be called white, but he obtained a grey pigment. some of this he put on the floor of his room for comparison with a piece of white paper. he allowed a beam of bright sunlight to fall upon the paper and the mixed colours side by side, and a friend he called in for his opinion pronounced that under these circumstances the mixed colours looked the whiter of the two. by repeated demonstrations newton thus established his great discovery of the composite character of light. he at once perceived that his researches had an important bearing upon the principles involved in the construction of a telescope. those who employed the telescope for looking at the stars, had been long aware of the imperfections which prevented all the various rays from being conducted to the same focus. but this imperfection had hitherto been erroneously accounted for. it had been supposed that the reason why success had not been attained in the construction of a refracting telescope was due to the fact that the object glass, made as it then was of a single piece, had not been properly shaped. mathematicians had abundantly demonstrated that a single lens, if properly figured, must conduct all rays of light to the same focus, provided all rays experienced equal refraction in passing through the glass. until newton's discovery of the composition of white light, it had been taken for granted that the several rays in a white beam were equally refrangible. no doubt if this had been the case, a perfect telescope could have been produced by properly shaping the object glass. but when newton had demonstrated that light was by no means so simple as had been supposed, it became obvious that a satisfactory refracting telescope was an impossibility when only a single object lens was employed, however carefully that lens might have been wrought. such an objective might, no doubt, be made to conduct any one group of rays of a particular shade to the same focus, but the rays of other colours in the beam of white light must necessarily travel somewhat astray. in this way newton accounted for a great part of the difficulties which had hitherto beset the attempts to construct a perfect refracting telescope. we now know how these difficulties can be, to a great extent, overcome, by employing for the objective a composite lens made of two pieces of glass possessing different qualities. to these achromatic object glasses, as they are called, the great development of astronomical knowledge, since newton's time, is due. but it must be remarked that, although the theoretical possibility of constructing an achromatic lens was investigated by newton, he certainly came to the conclusion that the difficulty could not be removed by employing a composite objective, with two different kinds of glass. in this his marvellous sagacity in the interpretation of nature seems for once to have deserted him. we can, however, hardly regret that newton failed to discover the achromatic objective, when we observe that it was in consequence of his deeming an achromatic objective to be impossible that he was led to the invention of the reflecting telescope. finding, as he believed, that the defects of the telescope could not be remedied by any application of the principle of refraction he was led to look in quite a different direction for the improvement of the tool on which the advancement of astronomy depended. the refraction of light depended as he had found, upon the colour of the light. the laws of reflection were, however, quite independent of the colour. whether rays be red or green, blue or yellow, they are all reflected in precisely the same manner from a mirror. accordingly, newton perceived that if he could construct a telescope the action of which depended upon reflection, instead of upon refraction, the difficulty which had hitherto proved an insuperable obstacle to the improvement of the instrument would be evaded. [plate: sir isaac newton's little reflector.] for this purpose newton fashioned a concave mirror from a mixture of copper and tin, a combination which gives a surface with almost the lustre of silver. when the light of a star fell upon the surface, an image of the star was produced in the focus of this mirror, and then this image was examined by a magnifying eye-piece. such is the principle of the famous reflecting telescope which bears the name of newton. the little reflector which he constructed, represented in the adjoining figure, is still preserved as one of the treasures of the royal society. the telescope tube had the very modest dimension of one inch in diameter. it was, however, the precursor of a whole series of magnificent instruments, each outstripping the other in magnitude, until at last the culminating point was attained in 1845, by the construction of lord rosse's mammoth reflector of six feet in aperture. newton's discovery of the composition of light led to an embittered controversy, which caused no little worry to the great philosopher. some of those who attacked him enjoyed considerable and, it must be admitted, even well-merited repute in the ranks of science. they alleged, however, that the elongation of the coloured band which newton had noticed was due to this, to that, or to the other--to anything, in fact, rather than to the true cause which newton assigned. with characteristic patience and love of truth, newton steadily replied to each such attack. he showed most completely how utterly his adversaries had misunderstood the subject, and how slight indeed was their acquaintance with the natural phenomenon in question. in reply to each point raised, he was ever able to cite fresh experiments and adduce fresh illustrations, until at last his opponents retired worsted from the combat. it has been often a matter for surprise that newton, throughout his whole career, should have taken so much trouble to expose the errors of those who attacked his views. he used even to do this when it plainly appeared that his adversaries did not understand the subject they were discussing. a philosopher might have said, "i know i am right, and whether others think i am right or not may be a matter of concern to them, but it is certainly not a matter about which i need trouble. if after having been told the truth they elect to remain in error, so much the worse for them; my time can be better employed than in seeking to put such people right." this, however, was not newton's method. he spent much valuable time in overthrowing objections which were often of a very futile description. indeed, he suffered a great deal of annoyance from the persistency, and in some cases one might almost say from the rancour, of the attacks which were made upon him. unfortunately for himself, he did not possess that capacity for sublime indifference to what men may say, which is often the happy possession of intellects greatly inferior to his. the subject of optics still continuing to engross newton's attention, he followed up his researches into the structure of the sunbeam by many other valuable investigations in connection with light. every one has noticed the beautiful colours manifested in a soap-bubble. here was a subject which not unnaturally attracted the attention of one who had expounded the colours of the spectrum with such success. he perceived that similar hues were produced by other thin plates of transparent material besides soap-bubbles, and his ingenuity was sufficient to devise a method by which the thicknesses of the different films could be measured. we can hardly, indeed, say that a like success attended his interpretation of these phenomena to that which had been so conspicuous in his explanation of the spectrum. it implies no disparagement to the sublime genius of newton to admit that the doctrines he put forth as to the causes of the colours in the soap-bubbles can be no longer accepted. we must remember that newton was a pioneer in accounting for the physical properties of light. the facts that he established are indeed unquestionable, but the explanations which he was led to offer of some of them are seen to be untenable in the fuller light of our present knowledge. [plate: sir isaac newton's sun-dial.] had newton done nothing beyond making his wonderful discoveries in light, his fame would have gone down to posterity as one of the greatest of nature's interpreters. but it was reserved for him to accomplish other discoveries, which have pushed even his analysis of the sunbeam into the background; it is he who has expounded the system of the universe by the discovery of the law of universal gravitation. the age had indeed become ripe for the advent of the genius of newton. kepler had discovered with marvellous penetration the laws which govern the movements of the planets around the sun, and in various directions it had been more or less vaguely felt that the explanation of kepler's laws, as well as of many other phenomena, must be sought for in connection with the attractive power of matter. but the mathematical analysis which alone could deal with this subject was wanting; it had to be created by newton. at woolsthorpe, in the year 1666, newton's attention appears to have been concentrated upon the subject of gravitation. whatever may be the extent to which we accept the more or less mythical story as to how the fall of an apple first directed the attention of the philosopher to the fact that gravitation must extend through space, it seems, at all events, certain that this is an excellent illustration of the line of reasoning which he followed. he argued in this way. the earth attracts the apple; it would do so, no matter how high might be the tree from which that apple fell. it would then seem to follow that this power which resides in the earth by which it can draw all external bodies towards it, extends far beyond the altitude of the loftiest tree. indeed, we seem to find no limit to it. at the greatest elevation that has ever been attained, the attractive power of the earth is still exerted, and though we cannot by any actual experiment reach an altitude more than a few miles above the earth, yet it is certain that gravitation would extend to elevations far greater. it is plain, thought newton, that an apple let fall from a point a hundred miles above this earth's surface, would be drawn down by the attraction, and would continually gather fresh velocity until it reached the ground. from a hundred miles it was natural to think of what would happen at a thousand miles, or at hundreds of thousands of miles. no doubt the intensity of the attraction becomes weaker with every increase in the altitude, but that action would still exist to some extent, however lofty might be the elevation which had been attained. it then occurred to newton, that though the moon is at a distance of two hundred and forty thousand miles from the earth, yet the attractive power of the earth must extend to the moon. he was particularly led to think of the moon in this connection, not only because the moon is so much closer to the earth than are any other celestial bodies, but also because the moon is an appendage to the earth, always revolving around it. the moon is certainly attracted to the earth, and yet the moon does not fall down; how is this to be accounted for? the explanation was to be found in the character of the moon's present motion. if the moon were left for a moment at rest, there can be no doubt that the attraction of the earth would begin to draw the lunar globe in towards our globe. in the course of a few days our satellite would come down on the earth with a most fearful crash. this catastrophe is averted by the circumstance that the moon has a movement of revolution around the earth. newton was able to calculate from the known laws of mechanics, which he had himself been mainly instrumental in discovering, what the attractive power of the earth must be, so that the moon shall move precisely as we find it to move. it then appeared that the very power which makes an apple fall at the earth's surface is the power which guides the moon in its orbit. [plate: sir isaac newton's telescope.] once this step had been taken, the whole scheme of the universe might almost be said to have become unrolled before the eye of the philosopher. it was natural to suppose that just as the moon was guided and controlled by the attraction of the earth, so the earth itself, in the course of its great annual progress, should be guided and controlled by the supreme attractive power of the sun. if this were so with regard to the earth, then it would be impossible to doubt that in the same way the movements of the planets could be explained to be consequences of solar attraction. it was at this point that the great laws of kepler became especially significant. kepler had shown how each of the planets revolves in an ellipse around the sun, which is situated on one of the foci. this discovery had been arrived at from the interpretation of observations. kepler had himself assigned no reason why the orbit of a planet should be an ellipse rather than any other of the infinite number of closed curves which might be traced around the sun. kepler had also shown, and here again he was merely deducing the results from observation, that when the movements of two planets were compared together, the squares of the periodic times in which each planet revolved were proportional to the cubes of their mean distances from the sun. this also kepler merely knew to be true as a fact, he gave no demonstration of the reason why nature should have adopted this particular relation between the distance and the periodic time rather than any other. then, too, there was the law by which kepler with unparalleled ingenuity, explained the way in which the velocity of a planet varies at the different points of its track, when he showed how the line drawn from the sun to the planet described equal areas around the sun in equal times. these were the materials with which newton set to work. he proposed to infer from these the actual laws regulating the force by which the sun guides the planets. here it was that his sublime mathematical genius came into play. step by step newton advanced until he had completely accounted for all the phenomena. in the first place, he showed that as the planet describes equal areas in equal times about the sun, the attractive force which the sun exerts upon it must necessarily be directed in a straight line towards the sun itself. he also demonstrated the converse truth, that whatever be the nature of the force which emanated from a sun, yet so long as that force was directed through the sun's centre, any body which revolved around it must describe equal areas in equal times, and this it must do, whatever be the actual character of the law according to which the intensity of the force varies at different parts of the planet's journey. thus the first advance was taken in the exposition of the scheme of the universe. the next step was to determine the law according to which the force thus proved to reside in the sun varied with the distance of the planet. newton presently showed by a most superb effort of mathematical reasoning, that if the orbit of a planet were an ellipse and if the sun were at one of the foci of that ellipse, the intensity of the attractive force must vary inversely as the square of the planet's distance. if the law had any other expression than the inverse square of the distance, then the orbit which the planet must follow would not be an ellipse; or if an ellipse, it would, at all events, not have the sun in the focus. hence he was able to show from kepler's laws alone that the force which guided the planets was an attractive power emanating from the sun, and that the intensity of this attractive power varied with the inverse square of the distance between the two bodies. these circumstances being known, it was then easy to show that the last of kepler's three laws must necessarily follow. if a number of planets were revolving around the sun, then supposing the materials of all these bodies were equally affected by gravitation, it can be demonstrated that the square of the periodic time in which each planet completes its orbit is proportional to the cube of the greatest diameter in that orbit. [plate: sir isaac newton's astrolabe.] these superb discoveries were, however, but the starting point from which newton entered on a series of researches, which disclosed many of the profoundest secrets in the scheme of celestial mechanics. his natural insight showed that not only large masses like the sun and the earth, and the moon, attract each other, but that every particle in the universe must attract every other particle with a force which varies inversely as the square of the distance between them. if, for example, the two particles were placed twice as far apart, then the intensity of the force which sought to bring them together would be reduced to one-fourth. if two particles, originally ten miles asunder, attracted each other with a certain force, then, when the distance was reduced to one mile, the intensity of the attraction between the two particles would be increased one-hundred-fold. this fertile principle extends throughout the whole of nature. in some cases, however, the calculation of its effect upon the actual problems of nature would be hardly possible, were it not for another discovery which newton's genius enabled him to accomplish. in the case of two globes like the earth and the moon, we must remember that we are dealing not with particles, but with two mighty masses of matter, each composed of innumerable myriads of particles. every particle in the earth does attract every particle in the moon with a force which varies inversely as the square of their distance. the calculation of such attractions is rendered feasible by the following principle. assuming that the earth consists of materials symmetrically arranged in shells of varying densities, we may then, in calculating its attraction, regard the whole mass of the globe as concentrated at its centre. similarly we may regard the moon as concentrated at the centre of its mass. in this way the earth and the moon can both be regarded as particles in point of size, each particle having, however, the entire mass of the corresponding globe. the attraction of one particle for another is a much more simple matter to investigate than the attraction of the myriad different points of the earth upon the myriad different points of the moon. many great discoveries now crowded in upon newton. he first of all gave the explanation of the tides that ebb and flow around our shores. even in the earliest times the tides had been shown to be related to the moon. it was noticed that the tides were specially high during full moon or during new moon, and this circumstance obviously pointed to the existence of some connection between the moon and these movements of the water, though as to what that connection was no one had any accurate conception until newton announced the law of gravitation. newton then made it plain that the rise and fall of the water was simply a consequence of the attractive power which the moon exerted upon the oceans lying upon our globe. he showed also that to a certain extent the sun produces tides, and he was able to explain how it was that when the sun and the moon both conspire, the joint result was to produce especially high tides, which we call "spring tides"; whereas if the solar tide was low, while the lunar tide was high, then we had the phenomenon of "neap" tides. but perhaps the most signal of newton's applications of the law of gravitation was connected with certain irregularities in the movements of the moon. in its orbit round the earth our satellite is, of course, mainly guided by the great attraction of our globe. if there were no other body in the universe, then the centre of the moon must necessarily perform an ellipse, and the centre of the earth would lie in the focus of that ellipse. nature, however, does not allow the movements to possess the simplicity which this arrangement would imply, for the sun is present as a source of disturbance. the sun attracts the moon, and the sun attracts the earth, but in different degrees, and the consequence is that the moon's movement with regard to the earth is seriously affected by the influence of the sun. it is not allowed to move exactly in an ellipse, nor is the earth exactly in the focus. how great was newton's achievement in the solution of this problem will be appreciated if we realise that he not only had to determine from the law of gravitation the nature of the disturbance of the moon, but he had actually to construct the mathematical tools by which alone such calculations could be effected. the resources of newton's genius seemed, however, to prove equal to almost any demand that could be made upon it. he saw that each planet must disturb the other, and in that way he was able to render a satisfactory account of certain phenomena which had perplexed all preceding investigators. that mysterious movement by which the pole of the earth sways about among the stars had been long an unsolved enigma, but newton showed that the moon grasped with its attraction the protuberant mass at the equatorial regions of the earth, and thus tilted the earth's axis in a way that accounted for the phenomenon which had been known but had never been explained for two thousand years. all these discoveries were brought together in that immortal work, newton's "principia." down to the year 1687, when the "principia" was published, newton had lived the life of a recluse at cambridge, being entirely occupied with those transcendent researches to which we have referred. but in that year he issued from his seclusion under circumstances of considerable historical interest. king james the second attempted an invasion of the rights and privileges of the university of cambridge by issuing a command that father francis, a benedictine monk, should be received as a master of arts in the university, without having taken the oaths of allegiance and supremacy. with this arbitrary command the university sternly refused to comply. the vice-chancellor was accordingly summoned to answer for an act of contempt to the authority of the crown. newton was one of nine delegates who were chosen to defend the independence of the university before the high court. they were able to show that charles the second, who had issued a mandamus under somewhat similar circumstances, had been induced after due consideration to withdraw it. this argument appeared satisfactory, and the university gained their case. newton's next step in public life was his election, by a narrow majority, as member for the university, and during the years 1688 and 1689, he seems to have attended to his parliamentary duties with considerable regularity. an incident which happened in 1692 was apparently the cause of considerable disturbance in newton's equanimity, if not in his health. he had gone to early morning chapel, leaving a lighted candle among his papers on his desk. tradition asserts that his little dog "diamond" upset the candle; at all events, when newton came back he found that many valuable papers had perished in a conflagration. the loss of these manuscripts seems to have had a serious effect. indeed, it has been asserted that the distress reduced newton to a state of mental aberration for a considerable time. this has, apparently, not been confirmed, but there is no doubt that he experienced considerable disquiet, for in writing on september 13th, 1693, to mr. pepys, he says: "i am extremely troubled at the embroilment i am in, and have neither ate nor slept well this twelve-month, nor have my former consistency of mind." notwithstanding the fame which newton had achieved, by the publication of his, "principia," and by all his researches, the state had not as yet taken any notice whatever of the most illustrious man of science that this or any other country has ever produced. many of his friends had exerted themselves to procure him some permanent appointment, but without success. it happened, however, that mr. montagu, who had sat with newton in parliament, was appointed chancellor of the exchequer in 1694. ambitious of distinction in his new office, mr. montagu addressed himself to the improvement of the current coin, which was then in a very debased condition. it fortunately happened that an opportunity occurred of appointing a new official in the mint; and mr. montagu on the 19th of march, 1695, wrote to offer mr. newton the position of warden. the salary was to be five or six hundred a year, and the business would not require more attendance than newton could spare. the lucasian professor accepted this post, and forthwith entered upon his new duties. the knowledge of physics which newton had acquired by his experiments was of much use in connection with his duties at the mint. he carried out the re-coinage with great skill in the course of two years, and as a reward for his exertions, he was appointed, in 1697, to the mastership of the mint, with a salary between 1,200 pounds and 1,500 pounds per annum. in 1701, his duties at the mint being so engrossing, he resigned his lucasian professorship at cambridge, and at the same time he had to surrender his fellowship at trinity college. this closed his connection with the university of cambridge. it should, however, be remarked that at a somewhat earlier stage in his career he was very nearly being appointed to an office which might have enabled the university to retain the great philosopher within its precincts. some of his friends had almost succeeded in securing his nomination to the provostship of king's college, cambridge; the appointment, however, fell through, inasmuch as the statute could not be evaded, which required that the provost of king's college should be in holy orders. in those days it was often the custom for illustrious mathematicians, when they had discovered a solution for some new and striking problem, to publish that problem as a challenge to the world, while withholding their own solution. a famous instance of this is found in what is known as the brachistochrone problem, which was solved by john bernouilli. the nature of this problem may be mentioned. it was to find the shape of the curve along which a body would slide down from one point (a) to another point (b) in the shortest time. it might at first be thought that the straight line from a to b, as it is undoubtedly the shortest distance between the points, would also be the path of quickest descent; but this is not so. there is a curved line, down which a bead, let us say, would run on a smooth wire from a to b in a shorter time than the same bead would require to run down the straight wire. bernouilli's problem was to find out what that curve must be. newton solved it correctly; he showed that the curve was a part of what is termed a cycloid--that is to say, a curve like that which is described by a point on the rim of a carriage-wheel as the wheel runs along the ground. such was newton's geometrical insight that he was able to transmit a solution of the problem on the day after he had received it, to the president of the royal society. in 1703 newton, whose world wide fame was now established, was elected president of the royal society. year after year he was re-elected to this distinguished position, and his tenure, which lasted twenty-five years, only terminated with his life. it was in discharge of his duties as president of the royal society that newton was brought into contact with prince george of denmark. in april, 1705, the queen paid a visit to cambridge as the guest of dr. bentley, the then master of trinity, and in a court held at trinity lodge on april 15th, 1705, the honour of knighthood was conferred upon the discoverer of gravitation. urged by illustrious friends, who sought the promotion of knowledge, newton gave his attention to the publication of a new edition of the "principia." his duties at the mint, however, added to the supreme duty of carrying on his original investigations, left him but little time for the more ordinary task of the revision. he was accordingly induced to associate with himself for this purpose a distinguished young mathematician, roger coates, a fellow of trinity college, cambridge, who had recently been appointed plumian professor of astronomy. on july 27th, 1713, newton, by this time a favourite at court, waited on the queen, and presented her with a copy of the new edition of the "principia." throughout his life newton appears to have been greatly interested in theological studies, and he specially devoted his attention to the subject of prophecy. he left behind him a manuscript on the prophecies of daniel and the apocalypse of st. john, and he also wrote various theological papers. many other subjects had from time to time engaged his attention. he studied the laws of heat; he experimented in pursuit of the dreams of the alchymist; while the philosopher who had revealed the mechanism of the heavens found occasional relaxation in trying to interpret hieroglyphics. in the last few years of his life he bore with fortitude a painful ailment, and on monday, march 20th, 1727, he died in the eighty-fifth year of his age. on tuesday, march 28th, he was buried in westminster abbey. though newton lived long enough to receive the honour that his astonishing discoveries so justly merited, and though for many years of his life his renown was much greater than that of any of his contemporaries, yet it is not too much to say that, in the years which have since elapsed, newton's fame has been ever steadily advancing, so that it never stood higher than it does at this moment. we hardly know whether to admire more the sublime discoveries at which he arrived, or the extraordinary character of the intellectual processes by which those discoveries were reached. viewed from either standpoint, newton's "principia" is incomparably the greatest work on science that has ever yet been produced. [plate: sir isaac newton's sun-dial in the royal society.] flamsteed. among the manuscripts preserved at greenwich observatory are certain documents in which flamsteed gives an account of his own life. we may commence our sketch by quoting the following passage from this autobiography:--"to keep myself from idleness, and to recreate myself, i have intended here to give some account of my life, in my youth, before the actions thereof, and the providences of god therein, be too far passed out of my memory; and to observe the accidents of all my years, and inclinations of my mind, that whosoever may light upon these papers may see i was not so wholly taken up, either with my father's business or my mathematics, but that i both admitted and found time for other as weighty considerations." the chief interest which attaches to the name of flamsteed arises from the fact that he was the first of the illustrious series of astronomers royal who have presided over greenwich observatory. in that capacity flamsteed was able to render material assistance to newton by providing him with the observations which his lunar theory required. john flamsteed was born at denby, in derbyshire, on the 19th of august, 1646. his mother died when he was three years old, and the second wife, whom his father took three years later, only lived until flamsteed was eight, there being also two younger sisters. in his boyhood the future astronomer tells us that he was very fond of those romances which affect boy's imagination, but as he writes, "at twelve years of age i left all the wild ones and betook myself to read the better sort of them, which, though they were not probable, yet carried no seeming impossibility in the picturing." by the time flamsteed was fifteen years old he had embarked in still more serious work, for he had read plutarch's "lives," tacitus' "roman history," and many other books of a similar description. in 1661 he became ill with some serious rheumatic affection, which obliged him to be withdrawn from school. it was then for the first time that he received the rudiments of a scientific education. he had, however, attained his sixteenth year before he made any progress in arithmetic. he tells us how his father taught him "the doctrine of fractions," and "the golden rule of three"--lessons which he seemed to have learned easily and quickly. one of the books which he read at this time directed his attention to astronomical instruments, and he was thus led to construct for himself a quadrant, by which he could take some simple astronomical observations. he further calculated a table to give the sun's altitudes at different hours, and thus displayed those tastes for practical astronomy which he lived to develop so greatly. it appears that these scientific studies were discountenanced by his father, who designed that his son should follow a business career. flamsteed's natural inclination, however, forced him to prosecute astronomical work, notwithstanding the impediments that lay in his path. unfortunately, his constitutional delicacy seems to have increased, and he had just completed his eighteenth year, "when," to use his own words, "the winter came on and thrust me again into the chimney, whence the heat and the dryness of the preceding summer had happily once before withdrawn me. but, it not being a fit season for physic, it was thought fit to let me alone this winter, and try the skill of another physician on me in the spring." it appears that at this time a quack named valentine greatrackes, was reputed to have effected most astonishing cures in ireland merely by the stroke of his hands, without the application of any medicine whatever. flamsteed's father, despairing of any remedy for his son from the legitimate branch of the profession, despatched him to ireland on august 26th, 1665, he being then, as recorded with astronomical accuracy, "nineteen years, six days, and eleven hours old." the young astronomer, accompanied by a friend, arrived on a tuesday at liverpool but the wind not being favourable, they remained there till the following friday, when a shift of the wind to the east took place. they embarked accordingly on a vessel called the supply at noon, and on saturday night came in sight of dublin. ere they could land, however, they were nearly being wrecked on lambay island. this peril safely passed, there was a long delay for quarantine before they were at last allowed on shore. on thursday, september 6th, they set out from dublin, where they had been sojourning at the "ship" hotel, in dame street, towards assaune, where greatrackes received his patients. [plate: flamsteed's house.] flamsteed gives an interesting account of his travels in ireland. they dined at naas on the first day, and on september 8th they reached carlow, a town which is described as one of the fairest they saw on their journey. by sunday morning, september 10th, having lost their way several times, they reached castleton, called commonly four mile waters. flamsteed inquired of the host in the inn where they might find a church, but was told that the minister lived twelve miles away, and that they had no sermon except when he came to receive his tithes once a year, and a woman added that "they had plenty enough of everything necessary except the word of god." the travellers accordingly went on to cappoquin, which lies up the river blackwater, on the road to lismore, eight miles from youghal. thence they immediately started on foot to assaune. about a mile from cappoquin, and entering into the house of mr. greatrackes, they saw him touch several patients, "whereof some were nearly cured, others were on the mending hand, and some on whom his strokes had no effect." flamsteed was touched by the famous quack on the afternoon of september 11th, but we are hardly surprised to hear his remark that "he found not his disease to stir." next morning the astronomer came again to see mr. greatrackes, who had "a kind of majestical yet affable presence, and a composed carriage." even after the third touching had been submitted to, no benefit seems to have been derived. we must, however record, to the credit of mr. greatrackes, that he refused to accept any payment from flamsteed, because he was a stranger. finding it useless to protract his stay any longer, flamsteed and his friend set out on their return to dublin. in the course of his journey he seems to have been much impressed with clonmel, which he describes as an "exceedingly pleasantly seated town." but in those days a journey to ireland was so serious an enterprise that when flamsteed did arrive safely back at derby after an absence of a month, he adds, "for god's providence in this journey, his name be praised, amen." as to the expected benefits to his health from the expedition we may quote his own words: "in the winter following i was indifferent hearty, and my disease was not so violent as it used to be at that time formerly. but whether through god's mercy i received this through mr. greatrackes' touch, or my journey and vomiting at sea, i am uncertain; but, by some circumstances, i guess that i received a benefit from both." it is evident that by this time flamsteed's interest in all astronomical matters had greatly increased. he studied the construction of sun-dials, he formed a catalogue of seventy of the fixed stars, with their places on the heavens, and he computed the circumstances of the solar eclipse which was to happen on june 22nd, 1666. it is interesting to note that even in those days the doctrines of the astrologers still found a considerable degree of credence, and flamsteed spent a good deal of his time in astrological studies and computations. he investigated the methods of casting a nativity, but a suspicion, or, indeed, rather more than a suspicion, seems to have crossed his mind as to the value of these astrological predictions, for he says in fine, "i found astrology to give generally strong conjectural hints, not perfect declarations." all this time, however, the future astronomer royal was steadily advancing in astronomical inquiries of a recondite nature. he had investigated the obliquity of the ecliptic with extreme care, so far as the circumstances of astronomical observation would at that time permit. he had also sought to discover the sun's distance from the earth in so far as it could be obtained by determining when the moon was exactly half illuminated, and he had measured, with much accuracy, the length of the tropical year. it will thus be seen that, even at the age of twenty, flamsteed had made marked progress, considering how much his time had been interfered with by ill-health. other branches of astronomy began also to claim his attention. we learn that in 1669 and 1670 he compared the planets jupiter and mars with certain fixed stars near which they passed. his instrumental means, though very imperfect, were still sufficient to enable him to measure the intervals on the celestial sphere between the planets and the stars. as the places of the stars were known, flamsteed was thus able to obtain the places of the planets. this is substantially the way in which astronomers of the present day still proceed when they desire to determine the places of the planets, inasmuch as, directly or indirectly those places are always obtained relatively to the fixed stars. by his observations at this early period, flamsteed was, it is true, not able to obtain any great degree of accuracy; he succeeded, however, in proving that the tables by which the places of the planets were ordinarily given were not to be relied upon. [plate: flamsteed.] flamsteed's labours in astronomy and in the allied branches of science were now becoming generally known, and he gradually came to correspond with many distinguished men of learning. one of the first occasions which brought the talents of the young astronomer into fame was the publication of some calculations concerning certain astronomical phenomena which were to happen in the year 1670. in the monthly revolution of the moon its disc passes over those stars which lie along its track. the disappearance of a star by the interposition of the moon is called an "occultation." owing to the fact that our satellite is comparatively near us, the position which the moon appears to occupy on the heavens varies from different parts of the earth, it consequently happens that a star which would be occulted to an observer in one locality, would often not be occulted to an observer who was situated elsewhere. even when an occultation is visible from both places, the times at which the star disappears from view will, generally speaking, be different. much calculation is therefore necessary to decide the circumstances under which the occultations of stars may be visible from any particular station. having a taste for such computations, flamsteed calculated the occultations which were to happen in the year 1670, it being the case that several remarkable stars would be passed over by the moon during this year. of course at the present time, we find such information duly set forth in the nautical almanac, but a couple of centuries ago there was no such source of astronomical knowledge as is now to be found in that invaluable publication, which astronomers and navigators know so well. flamsteed accordingly sent the results of his work to the president of the royal society. the paper which contained them was received very favourably, and at once brought flamsteed into notice among the most eminent members of that illustrious body, one of whom, mr. collins, became through life his faithful friend and constant correspondent. flamsteed's father was naturally gratified with the remarkable notice which his son was receiving from the great and learned; accordingly he desired him to go to london, that he might make the personal acquaintance of those scientific friends whom he had only known by correspondence previously. flamsteed was indeed glad to avail himself of this opportunity. thus he became acquainted with dr. barrow, and especially with newton, who was then lucasian professor of mathematics at cambridge. it seems to have been in consequence of this visit to london that flamsteed entered himself as a member of jesus college, cambridge. we have but little information as to his university career, but at all events he took his degree of m.a. on june 5th, 1674. up to this time it would seem that flamsteed had been engaged, to a certain extent, in the business carried on by his father. it is true that he does not give any explicit details, yet there are frequent references to journeys which he had to take on business matters. but the time now approached when flamsteed was to start on an independent career, and it appears that he took his degree in cambridge with the object of entering into holy orders, so that he might settle in a small living near derby, which was in the gift of a friend of his father, and would be at the disposal of the young astronomer. this scheme was, however, not carried out, but flamsteed does not tell us why it failed, his only remark being, that "the good providence of god that had designed me for another station ordered it otherwise." sir jonas moore, one of the influential friends whom flamsteed's talents had attracted, seems to have procured for him the position of king's astronomer, with a salary of 100 pounds per annum. a larger salary appears to have been designed at first for this office, which was now being newly created, but as flamsteed was resolved on taking holy orders, a lesser salary was in his case deemed sufficient. the building of the observatory, in which the first astronomer royal was to be installed, seems to have been brought about, or, at all events, its progress was accelerated, in a somewhat curious manner. a frenchman, named le sieur de s. pierre, came over to london to promulgate a scheme for discovering longitudes, then a question of much importance. he brought with him introductions to distinguished people, and his mission attracted a great deal of attention. the proposals which he made came under flamsteed's notice, who pointed out that the frenchman's projects were quite inapplicable in the present state of astronomical science, inasmuch as the places of the stars were not known with the degree of accuracy which would be necessary if such methods were to be rendered available. flamsteed then goes on to say:--"i heard no more of the frenchman after this; but was told that my letters had been shown king charles. he was startled at the assertion of the fixed stars' places being false in the catalogue, and said, with some vehemence, he must have them anew observed, examined, and corrected, for the use of his seamen." the first question to be settled was the site for the new observatory. hyde park and chelsea college were both mentioned as suitable localities, but, at sir christopher wren's suggestion, greenwich hill was finally resolved upon. the king made a grant of five hundred pounds of money. he gave bricks from tilbury fort, while materials, in the shape of wood, iron, and lead, were available from a gatehouse demolished in the tower. the king also promised whatever further material aid might be shown to be necessary. the first stone of the royal observatory was laid on august 10th, 1675, and within a few years a building was erected in which the art of modern practical astronomy was to be created. flamsteed strove with extraordinary diligence, and in spite of many difficulties, to obtain a due provision of astronomical instruments, and to arrange for the carrying on of his observations. notwithstanding the king's promises, the astronomer was, however, but scantily provided with means, and he had no assistants to help him in his work. it follows that all the observations, as well as the reductions, and, indeed, all the incidental work of the observatory, had to be carried on by himself alone. flamsteed, as we have seen, had, however, many staunch friends. sir jonas moore in particular at all times rendered him most valuable assistance, and encouraged him by the warm sympathy and keen interest which he showed in astronomy. the work of the first astronomer royal was frequently interrupted by recurrent attacks of the complaints to which we have already referred. he says himself that "his distempers stick so close that that he cannot remove them," and he lost much time by prostration from headaches, as well as from more serious affections. the year 1678 found him in the full tide of work in his observatory. he was specially engaged on the problem of the earth's motion, which he sought to derive from observations of the sun and of venus. but this, as well as many other astronomical researches which he undertook, were only subsidiary to that which he made the main task of his life, namely, the formation of a catalogue of fixed stars. at the time when flamsteed commenced his career, the only available catalogue of fixed stars was that of tycho brahe. this work had been published at the commencement of the seventeenth century, and it contained about a thousand stars. the positions assigned to these stars, though obtained with wonderful skill, considering the many difficulties under which tycho laboured, were quite inaccurate when judged by our modern standards. tycho's instruments were necessarily most rudely divided, and he had, of course, no telescopes to aid him. consequently it was merely by a process of sighting that he could obtain the places of the stars. it must further be remembered that tycho had no clocks, and no micrometers. he had, indeed, but little correct knowledge of the motions of the heavenly bodies to guide him. to determine the longitudes of a few principal stars he conceived the ingenious idea of measuring by day the position of venus with respect to the sun, an observation which the exceptional brightness of this planet rendered possible without telescopic aid, and then by night he observed the position of venus with regard to the stars. it has been well remarked by mr. baily, in his introduction to the "british catalogue of stars," that "flamsteed's observations, by a fortunate combination of circumstances, commenced a new and a brilliant era. it happened that, at that period, the powerful mind of newton was directed to this subject; a friendly intercourse then existed between these two distinguished characters; and thus the first observations that could lay any claim to accuracy were at once brought in aid of those deep researches in which our illustrious geometer was then engaged. the first edition of the 'principia' bears testimony to the assistance afforded by flamsteed to newton in these inquiries; although the former considers that the acknowledgment is not so ample as it ought to have been." although flamsteed's observations can hardly be said to possess the accuracy of those made in more recent times, when instruments so much superior to his have been available, yet they possess an interest of a special kind from their very antiquity. this circumstance renders them of particular importance to the astronomer, inasmuch as they are calculated to throw light on the proper motions of the stars. flamsteed's work may, indeed, be regarded as the origin of all subsequent catalogues, and the nomenclature which he adopted, though in some respects it can hardly be said to be very defensible, is, nevertheless, that which has been adopted by all subsequent astronomers. there were also a great many errors, as might be expected in a work of such extent, composed almost entirely of numerical detail. many of these errors have been corrected by baily himself, the assiduous editor of "flamsteed's life and works," for flamsteed was so harassed from various causes in the latter part of his life, and was so subject to infirmities all through his career, that he was unable to revise his computations with the care that would have been necessary. indeed, he observed many additional stars which he never included in the british catalogue. it is, as baily well remarks, "rather a matter of astonishment that he accomplished so much, considering his slender means, his weak frame, and the vexations which he constantly experienced." flamsteed had the misfortune, in the latter part of his life, to become estranged from his most eminent scientific contemporaries. he had supplied newton with places of the moon, at the urgent solicitation of the author of the "principia," in order that the lunar theory should be carefully compared with observation. but flamsteed appears to have thought that in newton's further request for similar information, he appeared to be demanding as a right that which flamsteed considered he was only called upon to render as a favour. a considerable dispute grew out of this matter, and there are many letters and documents, bearing on the difficulties which subsequently arose, that are not, perhaps, very creditable to either party. notwithstanding his feeble constitution, flamsteed lived to the age of seventy-three, his death occurring on the last day of the year 1719. halley. isaac newton was just fourteen years of age when the birth of edmund halley, who was destined in after years to become newton's warmly attached friend, and one of his most illustrious scientific contemporaries, took place. there can be little doubt that the fame as an astronomer which halley ultimately acquired, great as it certainly was, would have been even greater still had it not been somewhat impaired by the misfortune that he had to shine in the same sky as that which was illumined by the unparalleled genius of newton. edmund halley was born at haggerston, in the parish of st. leonard's, shoreditch, on october 29th, 1656. his father, who bore the same name as his famous son, was a soap-boiler in winchester street, london, and he had conducted his business with such success that he accumulated an ample fortune. i have been unable to obtain more than a very few particulars with respect to the early life of the future astronomer. it would, however, appear that from boyhood he showed considerable aptitude for the acquisition of various kinds of learning, and he also had some capacity for mechanical invention. halley seems to have received a sound education at st. paul's school, then under the care of dr. thomas gale. here, the young philosopher rapidly distanced his competitors in the various branches of ordinary school instruction. his superiority was, however, most conspicuous in mathematical studies, and, as a natural development of such tastes, we learn that by the time he had left school he had already made good progress in astronomy. at the age of seventeen he was entered as a commoner at queen's college, oxford, and the reputation that he brought with him to the university may be inferred from the remark of the writer of "athenae oxonienses," that halley came to oxford "with skill in latin, greek, and hebrew, and such a knowledge of geometry as to make a complete dial." though his studies were thus of a somewhat multifarious nature, yet it is plain that from the first his most favourite pursuit was astronomy. his earliest efforts in practical observation were connected with an eclipse which he observed from his father's house in winchester street. it also appears that he had studied theoretical branches of astronomy so far as to be conversant with the application of mathematics to somewhat abstruse problems. up to the time of kepler, philosophers had assumed almost as an axiom that the heavenly bodies must revolve in circles and that the motion of the planet around the orbit which it described must be uniform. we have already seen how that great philosopher, after very persevering labour, succeeded in proving that the orbits of the planets were not circles, but that they were ellipses of small eccentricity. kepler was, however, unable to shake himself free from the prevailing notion that the angular motion of the planet ought to be of a uniform character around some point. he had indeed proved that the motion round the focus of the ellipse in which the sun lies is not of this description. one of his most important discoveries even related to the fact that at some parts of its orbit a planet swings around the sun with greater angular velocity than at others. but it so happens that in elliptic tracks which differ but little from circles, as is the case with all the more important planetary orbits, the motion round the empty focus of the ellipse is very nearly uniform. it seemed natural to assume, that this was exactly the case, in which event each of the two foci of the ellipse would have had a special significance in relation to the movement of the planet. the youthful halley, however, demonstrated that so far as the empty focus was concerned, the movement of the planet around it, though so nearly uniform, was still not exactly so, and at the age of nineteen, he published a treatise on the subject which at once placed him in the foremost rank amongst theoretical astronomers. but halley had no intention of being merely an astronomer with his pen. he longed to engage in the practical work of observing. he saw that the progress of exact astronomy must depend largely on the determination of the positions of the stars with all attainable accuracy. he accordingly determined to take up this branch of work, which had been so successfully initiated by tycho brahe. at the present day, astronomers of the great national observatories are assiduously engaged in the determination of the places of the stars. a knowledge of the exact positions of these bodies is indeed of the most fundamental importance, not alone for the purposes of scientific astronomy, but also for navigation and for extensive operations of surveying in which accuracy is desired. the fact that halley determined to concentrate himself on this work shows clearly the scientific acumen of the young astronomer. halley, however, found that hevelius, at dantzig, and flamsteed, the astronomer royal at greenwich, were both engaged on work of this character. he accordingly determined to direct his energies in a way that he thought would be more useful to science. he resigned to the two astronomers whom i have named the investigation of the stars in the northern hemisphere, and he sought for himself a field hitherto almost entirely unworked. he determined to go to the southern hemisphere, there to measure and survey those stars which were invisible in europe, so that his work should supplement the labours of the northern astronomers, and that the joint result of his labours and of theirs might be a complete survey of the most important stars on the surface of the heavens. in these days, after so many ardent students everywhere have devoted themselves to the study of nature, it seems difficult for a beginner to find a virgin territory in which to commence his explorations. halley may, however, be said to have enjoyed the privilege of commencing to work in a magnificent region, the contents of which were previously almost entirely unknown. indeed none of the stars which were so situated as to have been invisible from tycho brahe's observatory at uraniborg, in denmark, could be said to have been properly observed. there was, no doubt, a rumour that a dutchman had observed southern stars from the island of sumatra, and certain stars were indicated in the southern heavens on a celestial globe. on examination, however, halley found that no reliance could be placed on the results which had been obtained, so that practically the field before him may be said to have been unworked. at the age of twenty, without having even waited to take that degree at the university which the authorities would have been glad to confer on so promising an undergraduate, this ardent student of nature sought his father's permission to go to the southern hemisphere for the purpose of studying the stars which lie around the southern pole. his father possessed the necessary means, and he had likewise the sagacity to encourage the young astronomer. he was indeed most anxious to make everything as easy as possible for so hopeful a son. he provided him with an allowance of 300 pounds a year, which was regarded as a very munificent provision in those days. halley was also furnished with letters of recommendation from king charles ii., as well as from the directors of the east india company. he accordingly set sail with his instruments in the year 1676, in one of the east india company's ships, for the island of st. helena, which he had selected as the scene of his labours. [plate: halley.] after an uneventful voyage of three months, the astronomer landed on st. helena, with his sextant of five and a half feet radius, and a telescope 24 feet long, and forthwith plunged with ardour into his investigation of the southern skies. he met, however, with one very considerable disappointment. the climate of this island had been represented to him as most favourable for astronomical observation; but instead of the pure blue skies he had been led to expect, he found that they were almost always more or less clouded, and that rain was frequent, so that his observations were very much interrupted. on this account he only remained at st. helena for a single year, having, during that time, and in spite of many difficulties, accomplished a piece of work which earned for him the title of "our southern tycho." thus did halley establish his fame as an astronomer on the same lonely rock in mid-atlantic, which nearly a century and a-half later became the scene of napoleon's imprisonment, when his star, in which he believed so firmly, had irretrievably set. on his return to england, halley prepared a map which showed the result of his labours, and he presented it to the king, in 1677. like his great predecessor tycho, halley did not altogether disdain the arts of the courtier, for he endeavoured to squeeze a new constellation into the group around the southern pole which he styled "the royal oak," adding a description to the effect that the incidents of which "the royal oak" was a symbol were of sufficient importance to be inscribed on the surface of the heavens. there is reason to think that charles ii. duly appreciated the scientific renown which one of his subjects had achieved, and it was probably through the influence of the king that halley was made a master of arts at oxford on november 18th, 1678. special reference was made on the occasion to his observations at st. helena, as evidence of unusual attainments in mathematics and astronomy. this degree was no small honour to such a young man, who, as we have seen, quitted his university before he had the opportunity of graduating in the ordinary manner. on november 30th, in the same year, the astronomer received a further distinction in being elected a fellow of the royal society. from this time forward he took a most active part in the affairs of the society, and the numerous papers which he read before it form a very valuable part of that notable series of volumes known as the "philosophical transactions." he was subsequently elected to the important office of secretary to the royal society, and he discharged the duties of his post until his appointment to greenwich necessitated his resignation. within a year of halley's election as a fellow of the royal society, he was chosen by the society to represent them in a discussion which had arisen with hevelius. the nature of this discussion, or rather the fact that any discussion should have been necessary, may seem strange to modern astronomers, for the point is one on which it would now seem impossible for there to be any difference of opinion. we must, however, remember that the days of halley were, comparatively speaking, the days of infancy as regards the art of astronomical observation, and issues that now seem obvious were often, in those early times, the occasions of grave and anxious consideration. the particular question on which halley had to represent the royal society may be simply stated. when tycho brahe made his memorable investigations into the places of the stars, he had no telescopes to help him. the famous instruments at uraniborg were merely provided with sights, by which the telescope was pointed to a star on the same principle as a rifle is sighted for a target. shortly after tycho's time, galileo invented the telescope. of course every one admitted at once the extraordinary advantages which the telescope had to offer, so far as the mere question of the visibility of objects was concerned. but the bearing of galileo's invention upon what we may describe as the measuring part of astronomy was not so immediately obvious. if a star be visible to the unaided eye, we can determine its place by such instruments as those which tycho used, in which no telescope is employed. we can, however, also avail ourselves of an instrument in which we view the star not directly but through the intervention of the telescope. can the place of the star be determined more accurately by the latter method than it can when the telescope is dispensed with? with our present knowledge, of course, there is no doubt about the answer; every one conversant with instruments knows that we can determine the place of a star far more accurately with the telescope than is possible by any mere sighting apparatus. in fact an observer would be as likely to make an error of a minute with the sighting apparatus in tycho's instrument, as he would be to make an error of a second with the modern telescope, or, to express the matter somewhat differently, we may say, speaking quite generally, that the telescopic method of determining the places of the stars does not lead to errors more than one-sixtieth part as great as which are unavoidable when we make use of tycho's method. but though this is so apparent to the modern astronomer, it was not at all apparent in the days of halley, and accordingly he was sent off to discuss the question with the continental astronomers. hevelius, as the representative of the older method, which tycho had employed with such success, maintained that an instrument could be pointed more accurately at a star by the use of sights than by the use of a telescope, and vigorously disputed the claims put forward by those who believed that the latter method was the more suitable. on may 14th, 1679, halley started for dantzig, and the energetic character of the man may be judged from the fact that on the very night of his arrival he commenced to make the necessary observations. in those days astronomical telescopes had only obtained a fractional part of the perfection possessed by the instruments in our modern observatories, and therefore it may not be surprising that the results of the trial were not immediately conclusive. halley appears to have devoted much time to the investigation; indeed, he remained at dantzig for more than a twelve-month. on his return to england, he spoke highly of the skill which hevelius exhibited in the use of his antiquated methods, but halley was nevertheless too sagacious an observer to be shaken in his preference for the telescopic method of observation. the next year we find our young astronomer starting for a continental tour, and we, who complain if the channel passage lasts more than an hour or two, may note halley's remark in writing to hooke on june 15th, 1680: "having fallen in with bad weather we took forty hours in the journey from dover to calais." the scientific distinction which he had already attained was such that he was received in paris with marked attention. a great deal of his time seems to have been passed in the paris observatory, where cassini, the presiding genius, himself an astronomer of well-deserved repute, had extended a hearty welcome to his english visitor. they made observations together of the place of the splendid comet which was then attracting universal attention, and halley found the work thus done of much use when he subsequently came to investigate the path pursued by this body. halley was wise enough to spare no pains to derive all possible advantages from his intercourse with the distinguished savants of the french capital. in the further progress of his tour he visited the principal cities of the continent, leaving behind him everywhere the memory of an amiable disposition and of a rare intelligence. after halley's return to england, in 1682, he married a young lady named mary tooke, with whom he lived happily, till her death fifty-five years later. on his marriage, he took up his abode in islington, where he erected his instruments and recommenced his observations. it has often been the good fortune of astronomers to render practical services to humanity by their investigations, and halley's achievements in this respect deserve to be noted. a few years after he had settled in england, he published an important paper on the variation of the magnetic compass, for so the departure of the needle from the true north is termed. this subject had indeed early engaged his attention, and he continued to feel much interest in it up to the end of his life. with respect to his labours in this direction, sir john herschel says: "to halley we owe the first appreciation of the real complexity of the subject of magnetism. it is wonderful indeed, and a striking proof of the penetration and sagacity of this extraordinary man, that with his means of information he should have been able to draw such conclusions, and to take so large and comprehensive a view of the subject as he appears to have done." in 1692, halley explained his theory of terrestrial magnetism, and begged captains of ships to take observations of the variations of the compass in all parts of the world, and to communicate them to the royal society, "in order that all the facts may be readily available to those who are hereafter to complete this difficult and complicated subject." the extent to which halley was in advance of his contemporaries, in the study of terrestrial magnetism, may be judged from the fact that the subject was scarcely touched after his time till the year 1811. the interest which he felt in it was not of a merely theoretical kind, nor was it one which could be cultivated in an easy-chair. like all true investigators, he longed to submit his theory to the test of experiment, and for that purpose halley determined to observe the magnetic variation for himself. he procured from king william iii. the command of a vessel called the "paramour pink," with which he started for the south seas in 1694. this particular enterprise was not, however, successful; for, on crossing the line, some of his men fell sick and one of his lieutenants mutinied, so that he was obliged to return the following year with his mission unaccomplished. the government cashiered the lieutenant, and halley having procured a second smaller vessel to accompany the "paramour pink," started once more in september, 1699. he traversed the atlantic to the 52nd degree of southern latitude, beyond which his further advance was stopped. "in these latitudes," he writes to say, "we fell in with great islands of ice of so incredible height and magnitude, that i scarce dare write my thoughts of it." on his return in 1700, halley published a general chart, showing the variation of the compass at the different places which he had visited. on these charts he set down lines connecting those localities at which the magnetic variation was identical. he thus set an example of the graphic representation of large masses of complex facts, in such a manner as to appeal at once to the eye, a method of which we make many applications in the present day. but probably the greatest service which halley ever rendered to human knowledge was the share in which he took in bringing newton's "principia" before the world. in fact, as dr. glaisher, writing in 1888, has truly remarked, "but for halley the 'principia' would not have existed." it was a visit from halley in the year 1684 which seems to have first suggested to newton the idea of publishing the results of his investigations on gravitation. halley, and other scientific contemporaries, had no doubt some faint glimmering of the great truth which only newton's genius was able fully to reveal. halley had indeed shown how, on the assumptions that the planets move in circular orbits round the sun, and that the squares of their periodic times are proportional to the cubes of their mean distances, it may be proved that the force acting on each planet must vary inversely as the square of its distance from the sun. since, however, each of the planets actually moves in an ellipse, and therefore, at continually varying distances from the sun, it becomes a much more difficult matter to account mathematically for the body's motions on the supposition that the attractive force varies inversely as the square of the distance. this was the question with which halley found himself confronted, but which his mathematical abilities were not adequate to solve. it would seem that both hooke and sir christopher wren were interested in the same problem; in fact, the former claimed to have arrived at a solution, but declined to make known his results, giving as an excuse his desire that others having tried and failed might learn to value his achievements all the more. halley, however, confessed that his attempts at the solution were unsuccessful, and wren, in order to encourage the other two philosophers to pursue the inquiry, offered to present a book of forty shillings value to either of them who should in the space of two months bring him a convincing proof of it. such was the value which sir christopher set on the law of gravitation, upon which the whole fabric of modern astronomy may be said to stand. finding himself unequal to the task, halley went down to cambridge to see newton on the subject, and was delighted to learn that the great mathematician had already completed the investigation. he showed halley that the motions of all the planets could be completely accounted for on the hypothesis of a force of attraction directed towards the sun, which varies inversely as the square of the distance from that body. halley had the genius to perceive the tremendous importance of newton's researches, and he ceased not to urge upon the recluse man of science the necessity for giving his new discoveries publication. he paid another visit to cambridge with the object of learning more with regard to the mathematical methods which had already conducted newton to such sublime truths, and he again encouraged the latter both to pursue his investigations, and to give some account of them to the world. in december of the same year halley had the gratification of announcing to the royal society that newton had promised to send that body a paper containing his researches on gravitation. it seems that at this epoch the finances of the royal society were at a very low ebb. this impecuniosity was due to the fact that a book by willoughby, entitled "de historia piscium," had been recently printed by the society at great expense. in fact, the coffers were so low that they had some difficulty in paying the salaries of their permanent officials. it appears that the public did not care about the history of fishes, or at all events the volume did not meet with the ready demand which was expected for it. indeed, it has been recorded that when halley had undertaken to measure the length of a degree of the earth's surface, at the request of the royal society, it was ordered that his expenses be defrayed either in 50 pounds sterling, or in fifty books of fishes. thus it happened that on june 2nd, the council, after due consideration of ways and means in connection with the issue of the principia, "ordered that halley should undertake the business of looking after the book and printing it at his own charge," which he engaged to do. it was, as we have elsewhere mentioned, characteristic of newton that he detested controversies, and he was, in fact, inclined to suppress the third book of the "principia" altogether rather than have any conflict with hooke with respect to the discoveries there enunciated. he also thought of changing the name of the work to de motu corporum libri duo, but upon second thoughts, he retained the original title, remarking, as he wrote to halley, "it will help the sale of the book, which i ought not to diminish, now it is yours," a sentence which shows conclusively, if further proof were necessary, that halley had assumed the responsibility of its publication. halley spared no pains in pushing forward the publication of his illustrious friend's great work, so that in the same year he was in a position to present a complete copy to king james ii., with a proper discourse of his own. halley also wrote a set of latin hexameters in praise of newton's genius, which he printed at the beginning of the work. the last line of this specimen of halley's poetic muse may be thus rendered: "nor mortals nearer may approach the gods." the intimate friendship between the two greatest astronomers of the time continued without interruption till the death of newton. it has, indeed, been alleged that some serious cause of estrangement arose between them. there is, however, no satisfactory ground for this statement; indeed, it may be regarded as effectually disposed of by the fact that, in the year 1727, halley took up the defence of his friend, and wrote two learned papers in support of newton's "system of chronology," which had been seriously attacked by a certain ecclesiastic. it is quite evident to any one who has studied these papers that halley's friendship for newton was as ardent as ever. the generous zeal with which halley adopted and defended the doctrines of newton with regard to the movements of the celestial bodies was presently rewarded by a brilliant discovery, which has more than any of his other researches rendered his name a familiar one to astronomers. newton, having explained the movement of the planets, was naturally led to turn his attention to comets. he perceived that their journeyings could be completely accounted for as consequences of the attraction of the sun, and he laid down the principles by which the orbit of a comet could be determined, provided that observations of its positions were obtained at three different dates. the importance of these principles was by no one more quickly recognised than by halley, who saw at once that it provided the means of detecting something like order in the movements of these strange wanderers. the doctrine of gravitation seemed to show that just as the planets revolved around the sun in ellipses, so also must the comets. the orbit, however, in the case of the comet, is so extremely elongated that the very small part of the elliptic path within which the comet is both near enough and bright enough to be seen from the earth, is indistinguishable from a parabola. applying these principles, halley thought it would be instructive to study the movements of certain bright comets, concerning which reliable observations could be obtained. at the expense of much labour, he laid down the paths pursued by twenty-four of these bodies, which had appeared between the years 1337 and 1698. amongst them he noticed three, which followed tracks so closely resembling each other, that he was led to conclude the so called three comets could only have been three different appearances of the same body. the first of these occurred in 1531, the second was seen by kepler in 1607, and the third by halley himself in 1682. these dates suggested that the observed phenomena might be due to the successive returns of one and the same comet after intervals of seventy-five or seventy-six years. on the further examination of ancient records, halley found that a comet had been seen in the year 1456, a date, it will be observed, seventy-five years before 1531. another had been observed seventy-six years earlier than 1456, viz., in 1380, and another seventy-five years before that, in 1305. as halley thus found that a comet had been recorded on several occasions at intervals of seventy-five or seventy-six years, he was led to the conclusion that these several apparitions related to one and the same object, which was an obedient vassal of the sun, performing an eccentric journey round that luminary in a period of seventy-five or seventy-six years. to realise the importance of this discovery, it should be remembered that before halley's time a comet, if not regarded merely as a sign of divine displeasure, or as an omen of intending disaster, had at least been regarded as a chance visitor to the solar system, arriving no one knew whence, and going no one knew whither. a supreme test remained to be applied to halley's theory. the question arose as to the date at which this comet would be seen again. we must observe that the question was complicated by the fact that the body, in the course of its voyage around the sun, was exposed to the incessant disturbing action produced by the attraction of the several planets. the comet therefore, does not describe a simple ellipse as it would do if the attraction of the sun were the only force by which its movement were controlled. each of the planets solicits the comet to depart from its track, and though the amount of these attractions may be insignificant in comparison with the supreme controlling force of the sun, yet the departure from the ellipse is quite sufficient to produce appreciable irregularities in the comet's movement. at the time when halley lived, no means existed of calculating with precision the effect of the disturbance a comet might experience from the action of the different planets. halley exhibited his usual astronomical sagacity in deciding that jupiter would retard the return of the comet to some extent. had it not been for this disturbance the comet would apparently have been due in 1757 or early in 1758. but the attraction of the great planet would cause delay, so that halley assigned, for the date of its re-appearance, either the end of 1758 or the beginning of 1759. halley knew that he could not himself live to witness the fulfilment of his prediction, but he says: "if it should return, according to our predictions, about the year 1758, impartial posterity will not refuse to acknowledge that this was first discovered by an englishman." this was, indeed, a remarkable prediction of an event to occur fifty-three years after it had been uttered. the way in which it was fulfilled forms one of the most striking episodes in the history of astronomy. the comet was first seen on christmas day, 1758, and passed through its nearest point to the sun on march 13th, 1759. halley had then been lying in his grave for seventeen years, yet the verification of his prophecy reflects a glory on his name which will cause it to live for ever in the annals of astronomy. the comet paid a subsequent visit in 1835, and its next appearance is due about 1910. halley next entered upon a labour which, if less striking to the imagination than his discoveries with regard to comets, is still of inestimable value in astronomy. he undertook a series of investigations with the object of improving our knowledge of the movements of the planets. this task was practically finished in 1719, though the results of it were not published until after his death in 1749. in the course of it he was led to investigate closely the motion of venus, and thus he came to recognise for the first time the peculiar importance which attaches to the phenomenon of the transit of this planet across the sun. halley saw that the transit, which was to take place in the year 1761, would afford a favourable opportunity for determining the distance of the sun, and thus learning the scale of the solar system. he predicted the circumstances of the phenomenon with an astonishing degree of accuracy, considering his means of information, and it is unquestionably to the exertions of halley in urging the importance of the matter upon astronomers that we owe the unexampled degree of interest taken in the event, and the energy which scientific men exhibited in observing it. the illustrious astronomer had no hope of being himself a witness of the event, for it could not happen till many years after his death. this did not, however, diminish his anxiety to impress upon those who would then be alive, the importance of the occurrence, nor did it lead him to neglect anything which might contribute to the success of the observations. as we now know, halley rather over-estimated the value of the transit of venus, as a means of determining the solar distance. the fact is that the circumstances are such that the observation of the time of contact between the edge of the planet and the edge of the sun cannot be made with the accuracy which he had expected. in 1691, halley became a candidate for the savilian professorship of astronomy at oxford. he was not, however, successful, for his candidature was opposed by flamsteed, the astronomer royal of the time, and another was appointed. he received some consolation for this particular disappointment by the fact that, in 1696, owing to newton's friendly influence, he was appointed deputy controller of the mint at chester, an office which he did not retain for long, as it was abolished two years later. at last, in 1703, he received what he had before vainly sought, and he was appointed to the savilian chair. his observations of the eclipse of the sun, which occurred in 1715, added greatly to halley's reputation. this phenomenon excited special attention, inasmuch as it was the first total eclipse of the sun which had been visible in london since the year 1140. halley undertook the necessary calculations, and predicted the various circumstances with a far higher degree of precision than the official announcement. he himself observed the phenomenon from the royal society's rooms, and he minutely describes the outer atmosphere of the sun, now known as the corona; without, however, offering an opinion as to whether it was a solar or a lunar appendage. at last halley was called to the dignified office which he of all men was most competent to fill. on february 9th, 1720, he was appointed astronomer royal in succession to flamsteed. he found things at the royal observatory in a most unsatisfactory state. indeed, there were no instruments, nor anything else that was movable; for such things, being the property of flamsteed, had been removed by his widow, and though halley attempted to purchase from that lady some of the instruments which his predecessor had employed, the unhappy personal differences which had existed between him and flamsteed, and which, as we have already seen, prevented his election as savilian professor of astronomy, proved a bar to the negotiation. greenwich observatory wore a very different appearance in those days, from that which the modern visitor, who is fortunate enough to gain admission, may now behold. not only did halley find it bereft of instruments, we learn besides that he had no assistants, and was obliged to transact the whole business of the establishment single-handed. in 1721, however, he obtained a grant of 500 pounds from the board of ordnance, and accordingly a transit instrument was erected in the same year. some time afterwards he procured an eight-foot quadrant, and with these instruments, at the age of sixty-four, he commenced a series of observations on the moon. he intended, if his life was spared, to continue his observations for a period of eighteen years, this being, as astronomers know, a very important cycle in connection with lunar movements. the special object of this vast undertaking was to improve the theory of the moon's motion, so that it might serve more accurately to determine longitudes at sea. this self-imposed task halley lived to carry to a successful termination, and the tables deduced from his observations, and published after his death, were adopted almost universally by astronomers, those of the french nation being the only exception. throughout his life halley had been singularly free from illness of every kind, but in 1737 he had a stroke of paralysis. notwithstanding this, however, he worked diligently at his telescope till 1739, after which his health began rapidly to give way. he died on january 14th, 1742, in the eighty-sixth year of his age, retaining his mental faculties to the end. he was buried in the cemetery of the church of lee in kent, in the same grave as his wife, who had died five years previously. we are informed by admiral smyth that pond, a later astronomer royal, was afterwards laid in the same tomb. halley's disposition seems to have been generous and candid, and wholly free from anything like jealousy or rancour. in person he was rather above the middle height, and slight in build; his complexion was fair, and he is said to have always spoken, as well as acted, with uncommon sprightliness. in the eloge pronounced upon him at the paris academie des sciences, of which halley had been made a member in 1719 it was said, "he possessed all the qualifications which were necessary to please princes who were desirous of instruction, with a great extent of knowledge and a constant presence of mind; his answers were ready, and at the same time pertinent, judicious, polite and sincere." [plate: greenwich observatory in halley's time.] thus we find that peter the great was one of his most ardent admirers. he consulted the astronomer on matters connected with shipbuilding, and invited him to his own table. but halley possessed nobler qualifications than the capacity of pleasing princes. he was able to excite and to retain the love and admiration of his equals. this was due to the warmth of his attachments, the unselfishness of his devotion to his friends, and to a vein of gaiety and good-humour which pervaded all his conversation. bradley. james bradley was descended from an ancient family in the county of durham. he was born in 1692 or 1693, at sherbourne, in gloucestershire, and was educated in the grammar school at northleach. from thence he proceeded in due course to oxford, where he was admitted a commoner at balliol college, on march 15th, 1711. much of his time, while an undergraduate, was passed in essex with his maternal uncle, the rev. james pound, who was a well-known man of science and a diligent observer of the stars. it was doubtless by intercourse with his uncle that young bradley became so expert in the use of astronomical instruments, but the immortal discoveries he subsequently made show him to have been a born astronomer. the first exhibition of bradley's practical skill seems to be contained in two observations which he made in 1717 and 1718. they have been published by halley, whose acuteness had led him to perceive the extraordinary scientific talents of the young astronomer. another illustration of the sagacity which bradley manifested, even at the very commencement of his astronomical career, is contained in a remark of halley's, who says: "dr. pound and his nephew, mr. bradley, did, myself being present, in the last opposition of the sun and mars this way demonstrate the extreme minuteness of the sun's parallax, and that it was not more than twelve seconds nor less than nine seconds." to make the significance of this plain, it should be observed that the determination of the sun's parallax is equivalent to the determination of the distance from the earth to the sun. at the time of which we are now writing, this very important unit of celestial measurement was only very imperfectly known, and the observations of pound and bradley may be interpreted to mean that, from their observations, they had come to the conclusion that the distance from the earth to the sun must be more than 94 millions of miles, and less than 125 millions. we now, of course, know that they were not exactly right, for the true distance of the sun is about 93 millions of miles. we cannot, however, but think that it was a very remarkable approach for the veteran astronomer and his brilliant nephew to make towards the determination of a magnitude which did not become accurately known till fifty years later. among the earliest parts of astronomical work to which bradley's attention was directed, were the eclipses of jupiter's satellites. these phenomena are specially attractive inasmuch as they can be so readily observed, and bradley found it extremely interesting to calculate the times at which the eclipses should take place, and then to compare his observations with the predicted times. from the success that he met with in this work, and from his other labours, bradley's reputation as an astronomer increased so greatly that on november the 6th, 1718, he was elected a fellow of the royal society. up to this time the astronomical investigations of bradley had been more those of an amateur than of a professional astronomer, and as it did not at first seem likely that scientific work would lead to any permanent provision, it became necessary for the youthful astronomer to choose a profession. it had been all along intended that he should enter the church, though for some reason which is not told us, he did not take orders as soon as his age would have entitled him to do so. in 1719, however, the bishop of hereford offered bradley the vicarage of bridstow, near ross, in monmouthshire, and on july 25th, 1720, he having then taken priest's orders, was duly instituted in his vicarage. in the beginning of the next year, bradley had some addition to his income from the proceeds of a welsh living, which, being a sinecure, he was able to hold with his appointment at bridstow. it appears, however, that his clerical occupations were not very exacting in their demands upon his time, for he was still able to pay long and often-repeated visits to his uncle at wandsworth, who, being himself a clergyman, seems to have received occasional assistance in his ministerial duties from his astronomical nephew. the time, however, soon arrived when bradley was able to make a choice between continuing to exercise his profession as a divine, or devoting himself to a scientific career. the savilian professorship of astronomy in the university of oxford became vacant by the death of dr. john keill. the statutes forbade that the savilian professor should also hold a clerical appointment, and mr. pound would certainly have been elected to the professorship had he consented to surrender his preferments in the church. but pound was unwilling to sacrifice his clerical position, and though two or three other candidates appeared in the field, yet the talents of bradley were so conspicuous that he was duly elected, his willingness to resign the clerical profession having been first ascertained. there can be no doubt that, with such influential friends as bradley possessed, he would have made great advances had he adhered to his profession as a divine. bishop hoadly, indeed, with other marks of favour, had already made the astronomer his chaplain. the engrossing nature of bradley's interest in astronomy decided him, however, to sacrifice all other prospects in comparison with the opening afforded by the savilian professorship. it was not that bradley found himself devoid of interest in clerical matters, but he felt that the true scope for such abilities as he possessed would be better found in the discharge of the scientific duties of the oxford chair than in the spiritual charge of a parish. on april the 26th, 1722, bradley read his inaugural lecture in that new position on which he was destined to confer such lustre. it must, of course, be remembered that in those early days the art of constructing the astronomical telescope was very imperfectly understood. the only known method for getting over the peculiar difficulties presented in the construction of the refracting telescope, was to have it of the most portentous length. in fact, bradley made several of his observations with an instrument of two hundred and twelve feet focus. in such a case, no tube could be used, and the object glass was merely fixed at the top of a high pole. notwithstanding the inconvenience and awkwardness of such an instrument, bradley by its means succeeded in making many careful measurements. he observed, for example, the transit of mercury over the sun's disc, on october 9th, 1723; he also observed the dimensions of the planet venus, while a comet which halley discovered on october the 9th, 1723, was assiduously observed at wanstead up to the middle of the ensuing month. the first of bradley's remarkable contributions to the "philosophical transactions" relates to this comet, and the extraordinary amount of work that he went through in connection therewith may be seen from an examination of his book of calculations which is still extant. the time was now approaching when bradley was to make the first of those two great discoveries by which his name has acquired a lustre that has placed him in the very foremost rank of astronomical discoverers. as has been often the case in the history of science, the first of these great successes was attained while he was pursuing a research intended for a wholly different purpose. it had long been recognised that as the earth describes a vast orbit, nearly two hundred million miles in diameter, in its annual journey round the sun, the apparent places of the stars should alter, to some extent, in correspondence with the changes in the earth's position. the nearer the star the greater the shift in its apparent place on the heavens, which must arise from the fact that it was seen from different positions in the earth's orbit. it had been pointed out that these apparent changes in the places of the stars, due to the movement of the earth, would provide the means of measuring the distances of the stars. as, however, these distances are enormously great in comparison with the orbit which the earth describes around the sun, the attempt to determine the distances of the stars by the shift in their positions had hitherto proved ineffectual. bradley determined to enter on this research once again; he thought that by using instruments of greater power, and by making measurements of increased delicacy, he would be able to perceive and to measure displacements which had proved so small as to elude the skill of the other astronomers who had previously made efforts in the same direction. in order to simplify the investigation as much as possible, bradley devoted his attention to one particular star, beta draconis, which happened to pass near his zenith. the object of choosing a star in this position was to avoid the difficulties which would be introduced by refraction had the star occupied any other place in the heavens than that directly overhead. we are still able to identify the very spot on which the telescope stood which was used in this memorable research. it was erected at the house then occupied by molyneux, on the western extremity of kew green. the focal length was 24 feet 3 inches, and the eye-glass was 3 and a half feet above the ground floor. the instrument was first set up on november 26th, 1725. if there had been any appreciable disturbance in the place of beta draconis in consequence of the movement of the earth around the sun, the star must appear to have the smallest latitude when in conjunction with the sun, and the greatest when in opposition. the star passed the meridian at noon in december, and its position was particularly noticed by molyneux on the third of that month. any perceptible displacement by parallax--for so the apparent change in position, due to the earth's motion, is called--would would have made the star shift towards the north. bradley, however, when observing it on the 17th, was surprised to find that the apparent place of the star, so far from shifting towards the north, as they had perhaps hoped it would, was found to lie a little more to the south than when it was observed before. he took extreme care to be sure that there was no mistake in his observation, and, true astronomer as he was, he scrutinized with the utmost minuteness all the circumstances of the adjustment of his instruments. still the star went to the south, and it continued so advancing in the same direction until the following march, by which time it had moved no less than twenty seconds south from the place which it occupied when the first observation was made. after a brief pause, in which no apparent movement was perceptible, the star by the middle of april appeared to be returning to the north. early in june it reached the same distance from the zenith which it had in december. by september the star was as much as thirty-nine seconds more to the north than it had been in march, then it returned towards the south, regaining in december the same situation which it had occupied twelve months before. this movement of the star being directly opposite to the movements which would have been the consequence of parallax, seemed to show that even if the star had any parallax its effects upon the apparent place were entirely masked by a much larger motion of a totally different description. various attempts were made to account for the phenomenon, but they were not successful. bradley accordingly determined to investigate the whole subject in a more thorough manner. one of his objects was to try whether the same movements which he had observed in one star were in any similar degree possessed by other stars. for this purpose he set up a new instrument at wanstead, and there he commenced a most diligent scrutiny of the apparent places of several stars which passed at different distances from the zenith. he found in the course of this research that other stars exhibited movements of a similar description to those which had already proved so perplexing. for a long time the cause of these apparent movements seemed a mystery. at last, however, the explanation of these remarkable phenomena dawned upon him, and his great discovery was made. one day when bradley was out sailing he happened to remark that every time the boat was laid on a different tack the vane at the top of the boat's mast shifted a little, as if there had been a slight change in the direction of the wind. after he had noticed this three or four times he made a remark to the sailors to the effect that it was very strange the wind should always happen to change just at the moment when the boat was going about. the sailors, however, said there had been no change in the wind, but that the alteration in the vane was due to the fact that the boat's course had been altered. in fact, the position of the vane was determined both by the course of the boat and the direction of the wind, and if either of these were altered there would be a corresponding change in the direction of the vane. this meant, of course, that the observer in the boat which was moving along would feel the wind coming from a point different from that in which the wind appeared to be blowing when the boat was at rest, or when it was sailing in some different direction. bradley's sagacity saw in this observation the clue to the difficulty which had so long troubled him. it had been discovered before the time of bradley that the passage of light through space is not an instantaneous phenomenon. light requires time for its journey. galileo surmised that the sun may have reached the horizon before we see it there, and it was indeed sufficiently obvious that a physical action, like the transmission of light, could hardly take place without requiring some lapse of time. the speed with which light actually travelled was, however, so rapid that its determination eluded all the means of experimenting which were available in those days. the penetration of roemer had previously detected irregularities in the observed times of the eclipses of jupiter's satellites, which were undoubtedly due to the interval which light required for stretching across the interplanetary spaces. bradley argued that as light can only travel with a certain speed, it may in a measure be regarded like the wind, which he noticed in the boat. if the observer were at rest, that is to say, if the earth were a stationary object, the direction in which the light actually does come would be different from that in which it appears to come when the earth is in motion. it is true that the earth travels but eighteen miles a second, while the velocity with which light is borne along attains to as much as 180,000 miles a second. the velocity of light is thus ten thousand times greater than the speed of the earth. but even though the wind blew ten thousand times faster than the speed with which the boat was sailing there would still be some change, though no doubt a very small change, in the position of the vane when the boat was in progress from the position it would have if the boat were at rest. it therefore occurred to this most acute of astronomers that when the telescope was pointed towards a star so as to place it apparently in the centre of the field of view, yet it was not generally the true position of the star. it was not, in fact, the position in which the star would have been observed had the earth been at rest. provided with this suggestion, he explained the apparent movements of the stars by the principle known as the "aberration of light." every circumstance was accounted for as a consequence of the relative movements of the earth and of the light from the star. this beautiful discovery not only established in the most forcible manner the nature of the movement of light; not only did it illustrate the truth of the copernican theory which asserted that the earth revolved around the sun, but it was also of the utmost importance in the improvement of practical astronomy. every observer now knows that, generally speaking, the position which the star appears to have is not exactly the position in which the star does actually lie. the observer is, however, able, by the application of the principles which bradley so clearly laid down, to apply to an observation the correction which is necessary to obtain from it the true place in which the object is actually situated. this memorable achievement at once conferred on bradley the highest astronomical fame. he tested his discovery in every way, but only to confirm its truth in the most complete manner. halley, the astronomer royal, died on the 14th, january, 1742, and bradley was immediately pointed out as his successor. he was accordingly appointed astronomer royal in february, 1742. on first taking up his abode at greenwich he was unable to conduct his observations owing to the wretched condition in which he found the instruments. he devoted himself, however, assiduously to their repair, and his first transit observation is recorded on the 25th july, 1742. he worked with such energy that on one day it appears that 255 transit observations were taken by himself alone, and in september, 1747, he had completed the series of observations which established his second great discovery, the nutation of the earth's axis. the way in which he was led to the detection of the nutation is strikingly illustrative of the extreme care with which bradley conducted his observations. he found that in the course of a twelve-month, when the star had completed the movement which was due to aberration, it did not return exactly to the same position which it had previously occupied. at first he thought this must be due to some instrumental error, but after closer examination and repeated study of the effect as manifested by many different stars, he came to the conclusion that its origin must be sought in some quite different source. the fact is that a certain change takes place in the apparent position of the stars which is not due to the movement of the star itself, but is rather to be attributed to changes in the points from which the star's positions are measured. we may explain the matter in this way. as the earth is not a sphere, but has protuberant parts at the equator, the attraction of the moon exercises on those protuberant parts a pulling effect which continually changes the direction of the earth's axis, and consequently the position of the pole must be in a state of incessant fluctuation. the pole to which the earth's axis points on the sky is, therefore, slowly changing. at present it happens to lie near the pole star, but it will not always remain there. it describes a circle around the pole of the ecliptic, requiring about 25,000 years for a complete circuit. in the course of its progress the pole will gradually pass now near one star and now near another, so that many stars will in the lapse of ages discharge the various functions which the present pole star does for us. in about 12,000 years, for instance, the pole will have come near the bright star, vega. this movement of the pole had been known for ages. but what bradley discovered was that the pole, instead of describing an uniform movement as had been previously supposed, followed a sinuous course now on one side and now on the other of its mean place. this he traced to the fluctuations of the moon's orbit, which undergoes a continuous change in a period of nineteen years. thus the efficiency with which the moon acts on the protuberant mass of the earth varies, and thus the pole is caused to oscillate. this subtle discovery, if perhaps in some ways less impressive than bradley's earlier achievements of the detection of the aberration of light, is regarded by astronomers as testifying even in a higher degree to his astonishing care and skill as an observer, and justly entitles him to a unique place among the astronomers whose discoveries have been effected by consummate practical skill in the use of astronomical instruments. of bradley's private or domestic life there is but little to tell. in 1744, soon after he became astronomer royal, he married a daughter of samuel peach, of chalford, in gloucestershire. there was but one child, a daughter, who became the wife of her cousin, rev. samuel peach, rector of compton, beauchamp, in berkshire. bradley's last two years of life were clouded by a melancholy depression of spirits, due to an apprehension that he should survive his rational faculties. it seems, however, that the ill he dreaded never came upon him, for he retained his mental powers to the close. he died on 13th july, 1762, aged seventy, and was buried at michinghamton. william herschel. william herschel, one of the greatest astronomers that has ever lived, was born at hanover, on the 15th november, 1738. his father, isaac herschel, was a man evidently of considerable ability, whose life was devoted to the study and practice of music, by which he earned a somewhat precarious maintenance. he had but few worldly goods to leave to his children, but he more than compensated for this by bequeathing to them a splendid inheritance of genius. touches of genius were, indeed, liberally scattered among the members of isaac's large family, and in the case of his forth child, william, and of a sister several years younger, it was united with that determined perseverance and rigid adherence to principle which enabled genius to fulfil its perfect work. a faithful chronicler has given us an interesting account of the way in which isaac herschel educated his sons; the narrative is taken from the recollections of one who, at the time we are speaking of, was an unnoticed little girl five or six years old. she writes:-"my brothers were often introduced as solo performers and assistants in the orchestra at the court, and i remember that i was frequently prevented from going to sleep by the lively criticisms on music on coming from a concert. often i would keep myself awake that i might listen to their animating remarks, for it made me so happy to see them so happy. but generally their conversation would branch out on philosophical subjects, when my brother william and my father often argued with such warmth that my mother's interference became necessary, when the names--euler, leibnitz, and newton--sounded rather too loud for the repose of her little ones, who had to be at school by seven in the morning." the child whose reminiscences are here given became afterwards the famous caroline herschel. the narrative of her life, by mrs. john herschel, is a most interesting book, not only for the account it contains of the remarkable woman herself, but also because it provides the best picture we have of the great astronomer to whom caroline devoted her life. this modest family circle was, in a measure, dispersed at the outbreak of the seven years' war in 1756. the french proceeded to invade hanover, which, it will be remembered, belonged at this time to the british dominions. young william herschel had already obtained the position of a regular performer in the regimental band of the hanoverian guards, and it was his fortune to obtain some experience of actual warfare in the disastrous battle of hastenbeck. he was not wounded, but he had to spend the night after the battle in a ditch, and his meditations on the occasion convinced him that soldiering was not the profession exactly adapted to his tastes. we need not attempt to conceal the fact that he left his regiment by the very simple but somewhat risky process of desertion. he had, it would seem, to adopt disguises to effect his escape. at all events, by some means he succeeded in eluding detection and reached england in safety. it is interesting to have learned on good authority that many years after this offence was committed it was solemnly forgiven. when herschel had become the famous astronomer, and as such visited king george at windsor, the king at their first meeting handed to him his pardon for deserting from the army, written out in due form by his majesty himself. it seems that the young musician must have had some difficulty in providing for his maintenance during the first few years of his abode in england. it was not until he had reached the age of twenty-two that he succeeded in obtaining any regular appointment. he was then made instructor of music to the durham militia. shortly afterwards, his talents being more widely recognised, he was appointed as organist at the parish church at halifax, and his prospects in life now being fairly favourable, and the seven years' war being over, he ventured to pay a visit to hanover to see his father. we can imagine the delight with which old isaac herschel welcomed his promising son, as well as his parental pride when a concert was given at which some of william's compositions were performed. if the father was so intensely gratified on this occasion, what would his feelings have been could he have lived to witness his son's future career? but this pleasure was not to be his, for he died many years before william became an astronomer. in 1766, about a couple of years after his return to england from this visit to his old home, we find that herschel had received a further promotion to be organist in the octagon chapel, at bath. bath was then, as now, a highly fashionable resort, and many notable personages patronised the rising musician. herschel had other points in his favour besides his professional skill; his appearance was good, his address was prepossessing, and even his nationality was a distinct advantage, inasmuch as he was a hanoverian in the reign of king george the third. on sundays he played the organ, to the great delight of the congregation, and on week-days he was occupied by giving lessons to private pupils, and in preparation for public performances. he thus came to be busily employed, and seems to have been in the enjoyment of comfortable means. [plate: 7, new king street, bath, where herschel lived.] from his earliest youth herschel had been endowed with that invaluable characteristic, an eager curiosity for knowledge. he was naturally desirous of perfecting himself in the theory of music, and thus he was led to study mathematics. when he had once tasted the charms of mathematics, he saw vast regions of knowledge unfolded before him, and in this way he was induced to direct his attention to astronomy. more and more this pursuit seems to have engrossed his attention, until at last it had become an absorbing passion. herschel was, however, still obliged, by the exigency of procuring a livelihood, to give up the best part of his time to his profession as a musician; but his heart was eagerly fixed on another science, and every spare moment was steadily devoted to astronomy. for many years, however, he continued to labour at his original calling, nor was it until he had attained middle age and become the most celebrated astronomer of the time, that he was enabled to concentrate his attention exclusively on his favourite pursuit. it was with quite a small telescope which had been lent him by a friend that herschel commenced his career as an observer. however, he speedily discovered that to see all he wanted to see, a telescope of far greater power would be necessary, and he determined to obtain this more powerful instrument by actually making it with his own hands. at first it may seem scarcely likely that one whose occupation had previously been the study and practice of music should meet with success in so technical an operation as the construction of a telescope. it may, however, be mentioned that the kind of instrument which herschel designed to construct was formed on a very different principle from the refracting telescopes with which we are ordinarily familiar. his telescope was to be what is termed a reflector. in this type of instrument the optical power is obtained by the use of a mirror at the bottom of the tube, and the astronomer looks down through the tube towards his mirror and views the reflection of the stars with its aid. its efficiency as a telescope depends entirely on the accuracy with which the requisite form has been imparted to the mirror. the surface has to be hollowed out a little, and this has to be done so truly that the slightest deviation from good workmanship in this essential particular would be fatal to efficient performance of the telescope. [plate: william herschel.] the mirror that herschel employed was composed of a mixture of two parts of copper to one of tin; the alloy thus obtained is an intensely hard material, very difficult to cast into the proper shape, and very difficult to work afterwards. it possesses, however, when polished, a lustre hardly inferior to that of silver itself. herschel has recorded hardly any particulars as to the actual process by which he cast and figured his reflectors. we are however, told that in later years, after his telescopes had become famous, he made a considerable sum of money by the manufacture and sale of great instruments. perhaps this may be the reason why he never found it expedient to publish any very explicit details as to the means by which his remarkable successes were obtained. [plate: caroline herschel.] since herschel's time many other astronomers, notably the late earl of rosse, have experimented in the same direction, and succeeded in making telescopes certainly far greater, and probably more perfect, than any which herschel appears to have constructed. the details of these later methods are now well known, and have been extensively practised. many amateurs have thus been able to make telescopes by following the instructions so clearly laid down by lord rosse and the other authorities. indeed, it would seem that any one who has a little mechanical skill and a good deal of patience ought now to experience no great difficulty in constructing a telescope quite as powerful as that which first brought herschel into fame. i should, however, mention that in these modern days the material generally used for the mirror is of a more tractable description than the metallic substance which was employed by herschel and by lord rosse. a reflecting telescope of the present day would not be fitted with a mirror composed of that alloy known as speculum metal, whose composition i have already mentioned. it has been found more advantageous to employ a glass mirror carefully figured and polished, just as a metallic mirror would have been, and then to impart to the polished glass surface a fine coating of silver laid down by a chemical process. the silver-on-glass mirrors are so much lighter and so much easier to construct that the more old-fashioned metallic mirrors may be said to have fallen into almost total disuse. in one respect however, the metallic mirror may still claim the advantage that, with reasonable care, its surface will last bright and untarnished for a much longer period than can the silver film on the glass. however, the operation of re-silvering a glass has now become such a simple one that the advantage this indicates is not relatively so great as might at first be supposed. [plate: street view, herschel house, slough.] some years elapsed after herschel's attention had been first directed to astronomy, before he reaped the reward of his exertions in the possession of a telescope which would adequately reveal some of the glories of the heavens. it was in 1774, when the astronomer was thirty-six years old, that he obtained his first glimpse of the stars with an instrument of his own construction. night after night, as soon as his musical labours were ended, his telescopes were brought out, sometimes into the small back garden of his house at bath, and sometimes into the street in front of his hall-door. it was characteristic of him that he was always endeavouring to improve his apparatus. he was incessantly making fresh mirrors, or trying new lenses, or combinations of lenses to act as eye-pieces, or projecting alterations in the mounting by which the telescope was supported. such was his enthusiasm that his house, we are told, was incessantly littered with the usual indications of the workman's presence, greatly to the distress of his sister, who, at this time, had come to take up her abode with him and look after his housekeeping. indeed, she complained that in his astronomical ardour he sometimes omitted to take off, before going into his workshop, the beautiful lace ruffles which he wore while conducting a concert, and that consequently they became soiled with the pitch employed in the polishing of his mirrors. this sister, who occupies such a distinct place in scientific history is the same little girl to whom we have already referred. from her earliest days she seems to have cherished a passionate admiration for her brilliant brother william. it was the proudest delight of her childhood as well as of her mature years to render him whatever service she could; no man of science was ever provided with a more capable or energetic helper than william herschel found in this remarkable woman. whatever work had to be done she was willing to bear her share in it, or even to toil at it unassisted if she could be allowed to do so. she not only managed all his domestic affairs, but in the grinding of the lenses and in the polishing of the mirrors she rendered every assistance that was possible. at one stage of the very delicate operation of fashioning a reflector, it is necessary for the workman to remain with his hand on the mirror for many hours in succession. when such labours were in progress, caroline used to sit by her brother, and enliven the time by reading stories aloud, sometimes pausing to feed him with a spoon while his hands were engaged on the task from which he could not desist for a moment. when mathematical work had to be done caroline was ready for it; she had taught herself sufficient to enable her to perform the kind of calculations, not, perhaps, very difficult ones, that herschel's work required; indeed, it is not too much to say that the mighty life-work which this man was enabled to perform could never have been accomplished had it not been for the self-sacrifice of this ever-loving and faithful sister. when herschel was at the telescope at night, caroline sat by him at her desk, pen in hand, ready to write down the notes of the observations as they fell from her brother's lips. this was no insignificant toil. the telescope was, of course, in the open air, and as herschel not unfrequently continued his observations throughout the whole of a long winter's night, there were but few women who could have accomplished the task which caroline so cheerfully executed. from dusk till dawn, when the sky was clear, were herschel's observing hours, and what this sometimes implied we can realise from the fact that caroline assures us she had sometimes to desist because the ink had actually frozen in her pen. the night's work over, a brief rest was taken, and while william had his labours for the day to attend to, caroline carefully transcribed the observations made during the night before, reduced all the figures and prepared everything in readiness for the observations that were to follow on the ensuing evening. but we have here been anticipating a little of the future which lay before the great astronomer; we must now revert to the history of his early work, at bath, in 1774, when herschel's scrutiny of the skies first commenced with an instrument of his own manufacture. for some few years he did not attain any result of importance; no doubt he made a few interesting observations, but the value of the work during those years is to be found, not in any actual discoveries which were accomplished, but in the practice which herschel obtained in the use of his instruments. it was not until 1782 that the great achievement took place by which he at once sprang into fame. [plate: garden view, herschel house, slough.] it is sometimes said that discoveries are made by accident, and, no doubt, to a certain extent, but only, i fancy to a very small extent, this statement may be true. it is, at all events, certain that such lucky accidents do not often fall to the lot of people unless those people have done much to deserve them. this was certainly the case with herschel. he appears to have formed a project for making a close examination of all the stars above a certain magnitude. perhaps he intended to confine this research to a limited region of the sky, but, at all events, he seems to have undertaken the work energetically and systematically. star after star was brought to the centre of the field of view of his telescope, and after being carefully examined was then displaced, while another star was brought forward to be submitted to the same process. in the great majority of cases such observations yield really nothing of importance; no doubt even the smallest star in the heavens would, if we could find out all about it, reveal far more than all the astronomers that were ever on the earth have even conjectured. what we actually learn about the great majority of stars is only information of the most meagre description. we see that the star is a little point of light, and we see nothing more. in the great review which herschel undertook he doubtless examined hundreds, or perhaps thousands of stars, allowing them to pass away without note or comment. but on an ever-memorable night in march, 1782, it happened that he was pursuing his task among the stars in the constellation of gemini. doubtless, on that night, as on so many other nights, one star after another was looked at only to be dismissed, as not requiring further attention. on the evening in question, however, one star was noticed which, to herschel's acute vision seemed different from the stars which in so many thousands are strewn over the sky. a star properly so called appears merely as a little point of light, which no increase of magnifying power will ever exhibit with a true disc. but there was something in the star-like object which herschel saw that immediately arrested his attention and made him apply to it a higher magnifying power. this at once disclosed the fact that the object possessed a disc, that is, a definite, measurable size, and that it was thus totally different from any one of the hundreds and thousands of stars which exist elsewhere in space. indeed, we may say at once that this little object was not a star at all; it was a planet. that such was its true nature was confirmed, after a little further observation, by perceiving that the body was shifting its place on the heavens relatively to the stars. the organist at the octagon chapel at bath had, therefore, discovered a new planet with his home-made telescope. i can imagine some one will say, "oh, there was nothing so wonderful in that; are not planets always being discovered? has not m. palisa, for instance, discovered about eighty of such objects, and are there not hundreds of them known nowadays?" this is, to a certain extent, quite true. i have not the least desire to detract from the credit of those industrious and sharp-sighted astronomers who have in modern days brought so many of these little objects within our cognisance. i think, however, it must be admitted that such discoveries have a totally different importance in the history of science from that which belongs to the peerless achievement of herschel. in the first place, it must be observed that the minor planets now brought to light are so minute that if a score of them were rolled to together into one lump it would not be one-thousandth part of the size of the grand planet discovered by herschel. this is, nevertheless, not the most important point. what marks herschel's achievement as one of the great epochs in the history of astronomy is the fact that the detection of uranus was the very first recorded occasion of the discovery of any planet whatever. for uncounted ages those who watched the skies had been aware of the existence of the five old planets--jupiter, mercury, saturn, venus, and mars. it never seems to have occurred to any of the ancient philosophers that there could be other similar objects as yet undetected over and above the well-known five. great then was the astonishment of the scientific world when the bath organist announced his discovery that the five planets which had been known from all antiquity must now admit the company of a sixth. and this sixth planet was, indeed, worthy on every ground to be received into the ranks of the five glorious bodies of antiquity. it was, no doubt, not so large as saturn, it was certainly very much less than jupiter; on the other hand, the new body was very much larger than mercury, than venus, or than mars, and the earth itself seemed quite an insignificant object in comparison with this newly added member of the solar system. in one respect, too, herschel's new planet was a much more imposing object than any one of the older bodies; it swept around the sun in a majestic orbit, far outside that of saturn, which had previously been regarded as the boundary of the solar system, and its stately progress required a period of not less than eighty-one years. king george the third, hearing of the achievements of the hanoverian musician, felt much interest in his discovery, and accordingly herschel was bidden to come to windsor, and to bring with him the famous telescope, in order to exhibit the new planet to the king, and to tell his majesty all about it. the result of the interview was to give herschel the opportunity for which he had so long wished, of being able to devote himself exclusively to science for the rest of his life. [plate: view of the observatory, herschel house, slough.] the king took so great a fancy to the astronomer that he first, as i have already mentioned, duly pardoned his desertion from the army, some twenty-five years previously. as a further mark of his favour the king proposed to confer on herschel the title of his majesty's own astronomer, to assign to him a residence near windsor, to provide him with a salary, and to furnish such funds as might be required for the erection of great telescopes, and for the conduct of that mighty scheme of celestial observation on which herschel was so eager to enter. herschel's capacity for work would have been much impaired if he had been deprived of the aid of his admirable sister, and to her, therefore, the king also assigned a salary, and she was installed as herschel's assistant in his new post. with his usually impulsive determination, herschel immediately cut himself free from all his musical avocations at bath, and at once entered on the task of making and erecting the great telescopes at windsor. there, for more than thirty years, he and his faithful sister prosecuted with unremitting ardour their nightly scrutiny of the sky. paper after paper was sent to the royal society, describing the hundreds, indeed the thousands, of objects such as double stars; nebulae and clusters, which were first revealed to human gaze during those midnight vigils. to the end of his life he still continued at every possible opportunity to devote himself to that beloved pursuit in which he had such unparalleled success. no single discovery of herschel's later years was, however, of the same momentous description as that which first brought him to fame. [plate: the 40-foot telescope as it was in the year 1863, herschel house, slough.] herschel married when considerably advanced in life and he lived to enjoy the indescribable pleasure of finding that his only son, afterwards sir john herschel, was treading worthily in his footsteps, and attaining renown as an astronomical observer, second only to that of his father. the elder herschel died in 1822, and his illustrious sister caroline then returned to hanover, where she lived for many years to receive the respect and attention which were so justly hers. she died at a very advanced age in 1848. laplace. the author of the "mecanique celeste" was born at beaumont-en-auge, near honfleur, in 1749, just thirteen years later than his renowned friend lagrange. his father was a farmer, but appears to have been in a position to provide a good education for a son who seemed promising. considering the unorthodoxy in religious matters which is generally said to have characterized laplace in later years, it is interesting to note that when he was a boy the subject which first claimed his attention was theology. he was, however, soon introduced to the study of mathematics, in which he presently became so proficient, that while he was still no more than eighteen years old, he obtained employment as a mathematical teacher in his native town. desiring wider opportunities for study and for the acquisition of fame than could be obtained in the narrow associations of provincial life, young laplace started for paris, being provided with letters of introduction to d'alembert, who then occupied the most prominent position as a mathematician in france, if not in the whole of europe. d'alembert's fame was indeed so brilliant that catherine the great wrote to ask him to undertake the education of her son, and promised the splendid income of a hundred thousand francs. he preferred, however, a quiet life of research in paris, although there was but a modest salary attached to his office. the philosopher accordingly declined the alluring offer to go to russia, even though catherine wrote again to say: "i know that your refusal arises from your desire to cultivate your studies and your friendships in quiet. but this is of no consequence: bring all your friends with you, and i promise you that both you and they shall have every accommodation in my power." with equal firmness the illustrious mathematician resisted the manifold attractions with which frederick the great sought to induce him, to take up his residence at berlin. in reading of these invitations we cannot but be struck at the extraordinary respect which was then paid to scientific distinction. it must be remembered that the discoveries of such a man as d'alembert were utterly incapable of being appreciated except by those who possessed a high degree of mathematical culture. we nevertheless find the potentates of russia and prussia entreating and, as it happens, vainly entreating, the most distinguished mathematician in france to accept the positions that they were proud to offer him. it was to d'alembert, the profound mathematician, that young laplace, the son of the country farmer, presented his letters of introduction. but those letters seem to have elicited no reply, whereupon laplace wrote to d'alembert submitting a discussion on some point in dynamics. this letter instantly produced the desired effect. d'alembert thought that such mathematical talent as the young man displayed was in itself the best of introductions to his favour. it could not be overlooked, and accordingly he invited laplace to come and see him. laplace, of course, presented himself, and ere long d'alembert obtained for the rising philosopher a professorship of mathematics in the military school in paris. this gave the brilliant young mathematician the opening for which he sought, and he quickly availed himself of it. laplace was twenty-three years old when his first memoir on a profound mathematical subject appeared in the memoirs of the academy at turin. from this time onwards we find him publishing one memoir after another in which he attacks, and in many cases successfully vanquishes, profound difficulties in the application of the newtonian theory of gravitation to the explanation of the solar system. like his great contemporary lagrange, he loftily attempted problems which demanded consummate analytical skill for their solution. the attention of the scientific world thus became riveted on the splendid discoveries which emanated from these two men, each gifted with extraordinary genius. laplace's most famous work is, of course, the "mecanique celeste," in which he essayed a comprehensive attempt to carry out the principles which newton had laid down, into much greater detail than newton had found practicable. the fact was that newton had not only to construct the theory of gravitation, but he had to invent the mathematical tools, so to speak, by which his theory could be applied to the explanation of the movements of the heavenly bodies. in the course of the century which had elapsed between the time of newton and the time of laplace, mathematics had been extensively developed. in particular, that potent instrument called the infinitesimal calculus, which newton had invented for the investigation of nature, had become so far perfected that laplace, when he attempted to unravel the movements of the heavenly bodies, found himself provided with a calculus far more efficient than that which had been available to newton. the purely geometrical methods which newton employed, though they are admirably adapted for demonstrating in a general way the tendencies of forces and for explaining the more obvious phenomena by which the movements of the heavenly bodies are disturbed, are yet quite inadequate for dealing with the more subtle effects of the law of gravitation. the disturbances which one planet exercises upon the rest can only be fully ascertained by the aid of long calculation, and for these calculations analytical methods are required. with an armament of mathematical methods which had been perfected since the days of newton by the labours of two or three generations of consummate mathematical inventors, laplace essayed in the "mecanique celeste" to unravel the mysteries of the heavens. it will hardly be disputed that the book which he has produced is one of the most difficult books to understand that has ever been written. in great part, of course, this difficulty arises from the very nature of the subject, and is so far unavoidable. no one need attempt to read the "mecanique celeste" who has not been naturally endowed with considerable mathematical aptitude which he has cultivated by years of assiduous study. the critic will also note that there are grave defects in laplace's method of treatment. the style is often extremely obscure, and the author frequently leaves great gaps in his argument, to the sad discomfiture of his reader. nor does it mend matters to say, as laplace often does say, that it is "easy to see" how one step follows from another. such inferences often present great difficulties even to excellent mathematicians. tradition indeed tells us that when laplace had occasion to refer to his own book, it sometimes happened that an argument which he had dismissed with his usual formula, "il est facile a voir," cost the illustrious author himself an hour or two of hard thinking before he could recover the train of reasoning which had been omitted. but there are certain parts of this great work which have always received the enthusiastic admiration of mathematicians. laplace has, in fact, created whole tracts of science, some of which have been subsequently developed with much advantage in the prosecution of the study of nature. judged by a modern code the gravest defect of laplace's great work is rather of a moral than of a mathematical nature. lagrange and he advanced together in their study of the mechanics of the heavens, at one time perhaps along parallel lines, while at other times they pursued the same problem by almost identical methods. sometimes the important result was first reached by lagrange, sometimes it was laplace who had the good fortune to make the discovery. it would doubtless be a difficult matter to draw the line which should exactly separate the contributions to astronomy made by one of these illustrious mathematicians, and the contributions made by the other. but in his great work laplace in the loftiest manner disdained to accord more than the very barest recognition to lagrange, or to any of the other mathematicians, newton alone excepted, who had advanced our knowledge of the mechanism of the heavens. it would be quite impossible for a student who confined his reading to the "mecanique celeste" to gather from any indications that it contains whether the discoveries about which he was reading had been really made by laplace himself or whether they had not been made by lagrange, or by euler, or by clairaut. with our present standard of morality in such matters, any scientific man who now brought forth a work in which he presumed to ignore in this wholesale fashion the contributions of others to the subject on which he was writing, would be justly censured and bitter controversies would undoubtedly arise. perhaps we ought not to judge laplace by the standard of our own time, and in any case i do not doubt that laplace might have made a plausible defence. it is well known that when two investigators are working at the same subjects, and constantly publishing their results, it sometimes becomes difficult for each investigator himself to distinguish exactly between what he has accomplished and that which must be credited to his rival. laplace may probably have said to himself that he was going to devote his energies to a great work on the interpretation of nature, that it would take all his time and all his faculties, and all the resources of knowledge that he could command, to deal justly with the mighty problems before him. he would not allow himself to be distracted by any side issue. he could not tolerate that pages should be wasted in merely discussing to whom we owe each formula, and to whom each deduction from such formula is due. he would rather endeavour to produce as complete a picture as he possibly could of the celestial mechanics, and whether it were by means of his mathematics alone, or whether the discoveries of others may have contributed in any degree to the result, is a matter so infinitesimally insignificant in comparison with the grandeur of his subject that he would altogether neglect it. "if lagrange should think," laplace might say, "that his discoveries had been unduly appropriated, the proper course would be for him to do exactly what i have done. let him also write a "mecanique celeste," let him employ those consummate talents which he possesses in developing his noble subject to the utmost. let him utilise every result that i or any other mathematician have arrived at, but not trouble himself unduly with unimportant historical details as to who discovered this, and who discovered that; let him produce such a work as he could write, and i shall heartily welcome it as a splendid contribution to our science." certain it is that laplace and lagrange continued the best of friends, and on the death of the latter it was laplace who was summoned to deliver the funeral oration at the grave of his great rival. the investigations of laplace are, generally speaking, of too technical a character to make it possible to set forth any account of them in such a work as the present. he did publish, however, one treatise, called the "systeme du monde," in which, without introducing mathematical symbols, he was able to give a general account of the theories of the celestial movements, and of the discoveries to which he and others had been led. in this work the great french astronomer sketched for the first time that remarkable doctrine by which his name is probably most generally known to those readers of astronomical books who are not specially mathematicians. it is in the "systeme du monde" that laplace laid down the principles of the nebular theory which, in modern days, has been generally accepted by those philosophers who are competent to judge, as substantially a correct expression of a great historical fact. [plate: laplace.] the nebular theory gives a physical account of the origin of the solar system, consisting of the sun in the centre, with the planets and their attendant satellites. laplace perceived the significance of the fact that all the planets revolved in the same direction around the sun; he noticed also that the movements of rotation of the planets on their axes were performed in the same direction as that in which a planet revolves around the sun; he saw that the orbits of the satellites, so far at least as he knew them, revolved around their primaries also in the same direction. nor did it escape his attention that the sun itself rotated on its axis in the same sense. his philosophical mind was led to reflect that such a remarkable unanimity in the direction of the movements in the solar system demanded some special explanation. it would have been in the highest degree improbable that there should have been this unanimity unless there had been some physical reason to account for it. to appreciate the argument let us first concentrate our attention on three particular bodies, namely the earth, the sun, and the moon. first the earth revolves around the sun in a certain direction, and the earth also rotates on its axis. the direction in which the earth turns in accordance with this latter movement might have been that in which it revolves around the sun, or it might of course have been opposite thereto. as a matter of fact the two agree. the moon in its monthly revolution around the earth follows also the same direction, and our satellite rotates on its axis in the same period as its monthly revolution, but in doing so is again observing this same law. we have therefore in the earth and moon four movements, all taking place in the same direction, and this is also identical with that in which the sun rotates once every twenty-five days. such a coincidence would be very unlikely unless there were some physical reason for it. just as unlikely would it be that in tossing a coin five heads or five tails should follow each other consecutively. if we toss a coin five times the chances that it will turn up all heads or all tails is but a small one. the probability of such an event is only one-sixteenth. there are, however, in the solar system many other bodies besides the three just mentioned which are animated by this common movement. among them are, of course, the great planets, jupiter, saturn, mars, venus, and mercury, and the satellites which attend on these planets. all these planets rotate on their axes in the same direction as they revolve around the sun, and all their satellites revolve also in the same way. confining our attention merely to the earth, the sun, and the five great planets with which laplace was acquainted, we have no fewer than six motions of revolution and seven motions of rotation, for in the latter we include the rotation of the sun. we have also sixteen satellites of the planets mentioned whose revolutions round their primaries are in the same direction. the rotation of the moon on its axis may also be reckoned, but as to the rotations of the satellites of the other planets we cannot speak with any confidence, as they are too far off to be observed with the necessary accuracy. we have thus thirty circular movements in the solar system connected with the sun and moon and those great planets than which no others were known in the days of laplace. the significant fact is that all these thirty movements take place in the same direction. that this should be the case without some physical reason would be just as unlikely as that in tossing a coin thirty times it should turn up all heads or all tails every time without exception. we can express the argument numerically. calculation proves that such an event would not generally happen oftener than once out of five hundred millions of trials. to a philosopher of laplace's penetration, who had made a special study of the theory of probabilities, it seemed well-nigh inconceivable that there should have been such unanimity in the celestial movements, unless there had been some adequate reason to account for it. we might, indeed, add that if we were to include all the objects which are now known to belong to the solar system, the argument from probability might be enormously increased in strength. to laplace the argument appeared so conclusive that he sought for some physical cause of the remarkable phenomenon which the solar system presented. thus it was that the famous nebular hypothesis took its rise. laplace devised a scheme for the origin of the sun and the planetary system, in which it would be a necessary consequence that all the movements should take place in the same direction as they are actually observed to do. let us suppose that in the beginning there was a gigantic mass of nebulous material, so highly heated that the iron and other substances which now enter into the composition of the earth and planets were then suspended in a state of vapour. there is nothing unreasonable in such a supposition indeed, we know as a matter of fact that there are thousands of such nebulae to be discerned at present through our telescopes. it would be extremely unlikely that any object could exist without possessing some motion of rotation; we may in fact assert that for rotation to be entirety absent from the great primeval nebula would be almost infinitely improbable. as ages rolled on, the nebula gradually dispersed away by radiation its original stores of heat, and, in accordance with well-known physical principles, the materials of which it was formed would tend to coalesce. the greater part of those materials would become concentrated in a mighty mass surrounded by outlying uncondensed vapours. there would, however, also be regions throughout the extent of the nebula, in which subsidiary centres of condensation would be found. in its long course of cooling, the nebula would, therefore, tend ultimately to form a mighty central body with a number of smaller bodies disposed around it. as the nebula was initially endowed with a movement of rotation, the central mass into which it had chiefly condensed would also revolve, and the subsidiary bodies would be animated by movements of revolution around the central body. these movements would be all pursued in one common direction, and it follows, from well-known mechanical principles, that each of the subsidiary masses, besides participating in the general revolution around the central body, would also possess a rotation around its axis, which must likewise be performed in the same direction. around the subsidiary bodies other objects still smaller would be formed, just as they themselves were formed relatively to the great central mass. as the ages sped by, and the heat of these bodies became gradually dissipated, the various objects would coalesce, first into molten liquid masses, and thence, at a further stage of cooling, they would assume the appearance of solid masses, thus producing the planetary bodies such as we now know them. the great central mass, on account of its preponderating dimensions, would still retain, for further uncounted ages, a large quantity of its primeval heat, and would thus display the splendours of a glowing sun. in this way laplace was able to account for the remarkable phenomena presented in the movements of the bodies of the solar system. there are many other points also in which the nebular theory is known to tally with the facts of observation. in fact, each advance in science only seems to make it more certain that the nebular hypothesis substantially represents the way in which our solar system has grown to its present form. not satisfied with a career which should be merely scientific, laplace sought to connect himself with public affairs. napoleon appreciated his genius, and desired to enlist him in the service of the state. accordingly he appointed laplace to be minister of the interior. the experiment was not successful, for he was not by nature a statesman. napoleon was much disappointed at the ineptitude which the great mathematician showed for official life, and, in despair of laplace's capacity as an administrator, declared that he carried the spirit of his infinitesimal calculus into the management of business. indeed, laplace's political conduct hardly admits of much defence. while he accepted the honours which napoleon showered on him in the time of his prosperity, he seems to have forgotten all this when napoleon could no longer render him service. laplace was made a marquis by louis xviii., a rank which he transmitted to his son, who was born in 1789. during the latter part of his life the philosopher lived in a retired country place at arcueile. here he pursued his studies, and by strict abstemiousness, preserved himself from many of the infirmities of old age. he died on march the 5th, 1827, in his seventy-eighth year, his last words being, "what we know is but little, what we do not know is immense." brinkley. provost baldwin held absolute sway in the university of dublin for forty-one years. his memory is well preserved there. the bursar still dispenses the satisfactory revenues which baldwin left to the college. none of us ever can forget the marble angels round the figure of the dying provost on which we used to gaze during the pangs of the examination hall. baldwin died in 1785, and was succeeded by francis andrews, a fellow of seventeen years' standing. as to the scholastic acquirements of andrews, all i can find is a statement that he was complimented by the polite professors of padua on the elegance and purity with which he discoursed to them in latin. andrews was also reputed to be a skilful lawyer. he was certainly a privy councillor and a prominent member of the irish house of commons, and his social qualities were excellent. perhaps it was baldwin's example that stimulated a desire in andrews to become a benefactor to his college. he accordingly bequeathed a sum of 3,000 pounds and an annual income of 250 pounds wherewith to build and endow an astronomical observatory in the university. the figures just stated ought to be qualified by the words of cautious ussher (afterwards the first professor of astronomy), that "this money was to arise from an accumulation of a part of his property, to commence upon a particular contingency happening to his family." the astronomical endowment was soon in jeopardy by litigation. andrews thought he had provided for his relations by leaving to them certain leasehold interests connected with the provost's estate. the law courts, however, held that these interests were not at the disposal of the testator, and handed them over to hely hutchinson, the next provost. the disappointed relations then petitioned the irish parliament to redress this grievance by transferring to them the moneys designed by andrews for the observatory. it would not be right, they contended, that the kindly intentions of the late provost towards his kindred should be frustrated for the sake of maintaining what they described as "a purely ornamental institution." the authorities of the college protested against this claim. counsel were heard, and a committee of the house made a report declaring the situation of the relations to be a hard one. accordingly, a compromise was made, and the dispute terminated. the selection of a site for the new astronomical observatory was made by the board of trinity college. the beautiful neighbourhood of dublin offered a choice of excellent localities. on the north side of the liffey an observatory could have been admirably placed, either on the remarkable promontory of howth or on the elevation of which dunsink is the summit. on the south side of dublin there are several eminences that would have been suitable: the breezy heaths at foxrock combine all necessary conditions; the obelisk hill at killiney would have given one of the most picturesque sites for an observatory in the world; while near delgany two or three other good situations could be mentioned. but the board of those pre-railway days was naturally guided by the question of proximity. dunsink was accordingly chosen as the most suitable site within the distance of a reasonable walk from trinity college. the northern boundary of the phoenix park approaches the little river tolka, which winds through a succession of delightful bits of sylvan scenery, such as may be found in the wide demesne of abbotstown and the classic shades of glasnevin. from the banks of the tolka, on the opposite side of the park, the pastures ascend in a gentle slope to culminate at dunsink, where at a distance of half a mile from the stream, of four miles from dublin, and at a height of 300 feet above the sea, now stands the observatory. from the commanding position of dunsink a magnificent view is obtained. to the east the sea is visible, while the southern prospect over the valley of the liffey is bounded by a range of hills and mountains extending from killiney to bray head, thence to the little sugar loaf, the two rock and the three rock mountains, over the flank of which the summit of the great sugar loaf is just perceptible. directly in front opens the fine valley of glenasmole, with kippure mountain, while the range can be followed to its western extremity at lyons. the climate of dunsink is well suited for astronomical observation. no doubt here, as elsewhere in ireland, clouds are abundant, but mists or haze are comparatively unusual, and fogs are almost unknown. the legal formalities to be observed in assuming occupation exacted a delay of many months; accordingly, it was not until the 10th december, 1782, that a contract could be made with mr. graham moyers for the erection of a meridian-room and a dome for an equatorial, in conjunction with a becoming residence for the astronomer. before the work was commenced at dunsink, the board thought it expedient to appoint the first professor of astronomy. they met for this purpose on the 22nd january, 1783, and chose the rev. henry ussher, a senior fellow of trinity college, dublin. the wisdom of the appointment was immediately shown by the assiduity with which ussher engaged in founding the observatory. in three years he had erected the buildings and equipped them with instruments, several of which were of his own invention. on the 19th of february, 1785, a special grant of 200 pounds was made by the board to dr. ussher as some recompense for his labours. it happened that the observatory was not the only scientific institution which came into being in ireland at this period; the newly-kindled ardour for the pursuit of knowledge led, at the same time, to the foundation of the royal irish academy. by a fitting coincidence, the first memoir published in the "transactions of the royal irish academy," was by the first andrews, professor of astronomy. it was read on the 13th of june, 1785, and bore the title, "account of the observatory belonging to trinity college," by the rev. h. ussher, d.d., m.r.i.a., f.r.s. this communication shows the extensive design that had been originally intended for dunsink, only a part of which was, however, carried out. for instance, two long corridors, running north and south from the central edifice, which are figured in the paper, never developed into bricks and mortar. we are not told why the original scheme had to be contracted; but perhaps the reason may be not unconnected with a remark of ussher's, that the college had already advanced from its own funds a sum considerably exceeding the original bequest. the picture of the building shows also the dome for the south equatorial, which was erected many years later. ussher died in 1790. during his brief career at the observatory, he observed eclipses, and is stated to have done other scientific work. the minutes of the board declare that the infant institution had already obtained celebrity by his labours, and they urge the claims of his widow to a pension, on the ground that the disease from which he died had been contracted by his nightly vigils. the board also promised a grant of fifty guineas as a help to bring out dr. ussher's sermons. they advanced twenty guineas to his widow towards the publication of his astronomical papers. they ordered his bust to be executed for the observatory, and offered "the death of ussher" as the subject of a prize essay; but, so far as i can find, neither the sermons nor the papers, neither the bust nor the prize essay, ever came into being. there was keen competition for the chair of astronomy which the death of ussher vacated. the two candidates were rev. john brinkley, of caius college, cambridge, a senior wrangler (born at woodbridge, suffolk, in 1763), and mr. stack, fellow of trinity college, dublin, and author of a book on optics. a majority of the board at first supported stack, while provost hely hutchinson and one or two others supported brinkley. in those days the provost had a veto at elections, so that ultimately stack was withdrawn and brinkley was elected. this took place on the 11th december, 1790. the national press of the day commented on the preference shown to the young englishman, brinkley, over his irish rival. an animated controversy ensued. the provost himself condescended to enter the lists and to vindicate his policy by a long letter in the "public register" or "freeman's journal," of 21st december, 1790. this letter was anonymous, but its authorship is obvious. it gives the correspondence with maskelyne and other eminent astronomers, whose advice and guidance had been sought by the provost. it also contends that "the transactions of the board ought not to be canvassed in the newspapers." for this reference, as well as for much other information, i am indebted to my friend, the rev. john stubbs, d.d. [plate: the observatory, dunsink. from a photograph by w. lawrence, upper sackville street, dublin.] the next event in the history of the observatory was the issue of letters patent (32 geo. iii., a.d. 1792), in which it is recited that "we grant and ordain that there shall be forever hereafter a professor of astronomy, on the foundation of dr. andrews, to be called and known by the name of the royal astronomer of ireland." the letters prescribe the various duties of the astronomer and the mode of his election. they lay down regulations as to the conduct of the astronomical work, and as to the choice of an assistant. they direct that the provost and the senior fellows shall make a thorough inspection of the observatory once every year in june or july; and this duty was first undertaken on the 5th of july, 1792. it may be noted that the date on which the celebration of the tercentenary of the university was held happens to coincide with the centenary of the first visitation of the observatory. the visitors on the first occasion were a. murray, matthew young, george hall, and john barrett. they record that they find the buildings, books and instruments in good condition; but the chief feature in this report, as well as in many which followed it, related to a circumstance to which we have not yet referred. in the original equipment of the observatory, ussher, with the natural ambition of a founder, desired to place in it a telescope of more magnificent proportions than could be found anywhere else. the board gave a spirited support to this enterprise, and negotiations were entered into with the most eminent instrument-maker of those days. this was jesse ramsden (1735-1800), famous as the improver of the sextant, as the constructor of the great theodolite used by general roy in the english survey, and as the inventor of the dividing engine for graduating astronomical instruments. ramsden had built for sir george schuckburgh the largest and most perfect equatorial ever attempted. he had constructed mural quadrants for padua and verona, which elicited the wonder of astronomers when dr. maskelyne declared he could detect no error in their graduation so large as two seconds and a half. but ramsden maintained that even better results would be obtained by superseding the entire quadrant by the circle. he obtained the means of testing this prediction when he completed a superb circle for palermo of five feet diameter. finding his anticipations were realised, he desired to apply the same principles on a still grander scale. ramsden was in this mood when he met with dr. ussher. the enthusiasm of the astronomer and the instrument-maker communicated itself to the board, and a tremendous circle, to be ten feet in diameter, was forthwith projected. projected, but never carried out. after ramsden had to some extent completed a 10-foot circle, he found such difficulties that he tried a 9-foot, and this again he discarded for an 8-foot, which was ultimately accomplished, though not entirely by himself. notwithstanding the contraction from the vast proportions originally designed, the completed instrument must still be regarded as a colossal piece of astronomical workmanship. even at this day i do not know that any other observatory can show a circle eight feet in diameter graduated all round. i think it is professor piazzi smith who tells us how grateful he was to find a large telescope he had ordered finished by the opticians on the very day they had promised it. the day was perfectly correct; it was only the year that was wrong. a somewhat remarkable experience in this direction is chronicled by the early reports of the visitors to dunsink observatory. i cannot find the date on which the great circle was ordered from ramsden, but it is fixed with sufficient precision by an allusion in ussher's paper to the royal irish academy, which shows that by the 13th june, 1785, the order had been given, but that the abandonment of the 10-foot scale had not then been contemplated. it was reasonable that the board should allow ramsden ample time for the completion of a work at once so elaborate and so novel. it could not have been finished in a year, nor would there have been much reason for complaint if the maker had found he required two or even three years more. seven years gone, and still no telescope, was the condition in which the board found matters at their first visitation in 1792. they had, however, assurances from ramsden that the instrument would be completed within the year; but, alas for such promises, another seven years rolled on, and in 1799 the place for the great circle was still vacant at dunsink. ramsden had fallen into bad health, and the board considerately directed that "inquiries should be made." next year there was still no progress, so the board were roused to threaten ramsden with a suit at law; but the menace was never executed, for the malady of the great optician grew worse, and he died that year. affairs had now assumed a critical aspect, for the college had advanced much money to ramsden during these fifteen years, and the instrument was still unfinished. an appeal was made by the provost to dr. maskelyne, the astronomer royal of england, for his advice and kindly offices in this emergency. maskelyne responds--in terms calculated to allay the anxiety of the bursar--"mr. ramsden has left property behind him, and the college can be in no danger of losing both their money and the instrument." the business of ramsden was then undertaken by berge, who proceeded to finish the circle quite as deliberately as his predecessor. after four years berge promised the instrument in the following august, but it did not come. two years later (1806) the professor complains that he can get no answer from berge. in 1807, it is stated that berge will send the telescope in a month. he did not; but in the next year (1808), about twenty-three years after the great circle was ordered, it was erected at dunsink, where it is still to be seen. the following circumstances have been authenticated by the signatures of provosts, proctors, bursars, and other college dignitaries:--in 1793 the board ordered two of the clocks at the observatory to be sent to mr. crosthwaite for repairs. seven years later, in 1800, mr. crosthwaite was asked if the clocks were ready. this impatience was clearly unreasonable, for even in four more years, 1804, we find the two clocks were still in hand. two years later, in 1806, the board determined to take vigorous action by asking the bursar to call upon crosthwaite. this evidently produced some effect, for in the following year, 1807, the professor had no doubt that the clocks would be speedily returned. after eight years more, in 1815, one of the clocks was still being repaired, and so it was in 1816, which is the last record we have of these interesting time-pieces. astronomers are, however, accustomed to deal with such stupendous periods in their calculations, that even the time taken to repair a clock seems but small in comparison. the long tenure of the chair of astronomy by brinkley is divided into two nearly equal periods by the year in which the great circle was erected. brinkley was eighteen years waiting for his telescope, and he had eighteen years more in which to use it. during the first of these periods brinkley devoted himself to mathematical research; during the latter he became a celebrated astronomer. brinkley's mathematical labours procured for their author some reputation as a mathematician. they appear to be works of considerable mathematical elegance, but not indicating any great power of original thought. perhaps it has been prejudicial to brinkley's fame in this direction, that he was immediately followed in his chair by so mighty a genius as william rowan hamilton. after the great circle had been at last erected, brinkley was able to begin his astronomical work in earnest. nor was there much time to lose. he was already forty-five years old, a year older than was herschel when he commenced his immortal career at slough. stimulated by the consciousness of having the command of an instrument of unique perfection, brinkley loftily attempted the very highest class of astronomical research. he resolved to measure anew with his own eye and with his own hand the constants of aberration and of nutation. he also strove to solve that great problem of the universe, the discovery of the distance of a fixed star. these were noble problems, and they were nobly attacked. but to appraise with justice this work of brinkley, done seventy years ago, we must not apply to it the same criterion as we would think right to apply to similar work were it done now. we do not any longer use brinkley's constant of aberration, nor do we now think that brinkley's determinations of the star distances were reliable. but, nevertheless, his investigations exercised a marked influence on the progress of science; they stimulated the study of the principles on which exact measurements were to be conducted. brinkley had another profession in addition to that of an astronomer. he was a divine. when a man endeavours to pursue two distinct occupations concurrently, it will be equally easy to explain why his career should be successful, or why it should be the reverse. if he succeeds, he will, of course, exemplify the wisdom of having two strings to his bow. should he fail, it is, of course, because he has attempted to sit on two stools at once. in brinkley's case, his two professions must be likened to the two strings rather than to the two stools. it is true that his practical experience of his clerical life was very slender. he had made no attempt to combine the routine of a parish with his labours in the observatory. nor do we associate a special eminence in any department of religious work with his name. if, however, we are to measure brinkley's merits as a divine by the ecclesiastical preferment which he received, his services to theology must have rivalled his services to astronomy. having been raised step by step in the church, he was at last appointed to the see of cloyne, in 1826, as the successor of bishop berkeley. now, though it was permissible for the archdeacon to be also the andrews professor, yet when the archdeacon became a bishop, it was understood that he should transfer his residence from the observatory to the palace. the chair of astronomy accordingly became vacant. brinkley's subsequent career seems to have been devoted entirely to ecclesiastical matters, and for the last ten years of his life he did not contribute a paper to any scientific society. arago, after a characteristic lament that brinkley should have forsaken the pursuit of science for the temporal and spiritual attractions of a bishopric, pays a tribute to the conscientiousness of the quondam astronomer, who would not even allow a telescope to be brought into the palace lest his mind should be distracted from his sacred duties. the good bishop died on the 13th september, 1835. he was buried in the chapel of trinity college, and a fine monument to his memory is a familiar object at the foot of the noble old staircase of the library. the best memorial of brinkley is his admirable book on the "elements of plane astronomy." it passed through many editions in his lifetime, and even at the present day the same work, revised first by dr. luby, and more recently by the rev. dr. stubbs and dr. brunnow, has a large and well-merited circulation. john herschel. this illustrious son of an illustrious father was born at slough, near windsor, on the 7th march, 1792. he was the only child of sir william herschel, who had married somewhat late in life, as we have already mentioned. [plate: astronometer made by sir j. herschel to compare the light of certain stars by the intervention of the moon.] the surroundings among which the young astronomer was reared afforded him an excellent training for that career on which he was to enter, and in which he was destined to attain a fame only less brilliant than that of his father. the circumstances of his youth permitted him to enjoy one great advantage which was denied to the elder herschel. he was able, from his childhood, to devote himself almost exclusively to intellectual pursuits. william herschel, in the early part of his career, had only been able to snatch occasional hours for study from his busy life as a professional musician. but the son, having been born with a taste for the student's life, was fortunate enough to have been endowed with the leisure and the means to enjoy it from the commencement. his early years have been so well described by the late professor pritchard in the "report of the council of the royal astronomical society for 1872," that i venture to make an extract here:-"a few traits of john herschel's boyhood, mentioned by himself in his maturer life, have been treasured up by those who were dear to him, and the record of some of them may satisfy a curiosity as pardonable as inevitable, which craves to learn through what early steps great men or great nations become illustrious. his home was singular, and singularly calculated to nurture into greatness any child born as john herschel was with natural gifts, capable of wide development. at the head of the house there was the aged, observant, reticent philosopher, and rarely far away his devoted sister, caroline herschel, whose labours and whose fame are still cognisable as a beneficent satellite to the brighter light of her illustrious brother. it was in the companionship of these remarkable persons, and under the shadow of his father's wonderful telescope, that john herschel passed his boyish years. he saw them, in silent but ceaseless industry, busied about things which had no apparent concern with the world outside the walls of that well-known house, but which, at a later period of his life, he, with an unrivalled eloquence, taught his countrymen to appreciate as foremost among those living influences which but satisfy and elevate the noblest instincts of our nature. what sort of intercourse passed between the father and the boy may be gathered from an incident or two which he narrated as having impressed themselves permanently on the memory of his youth. he once asked his father what he thought was the oldest of all things. the father replied, after the socratic method, by putting another question: 'and what do you yourself suppose is the oldest of all things?' the boy was not successful in his answers, thereon the old astronomer took up a small stone from the garden walk: 'there, my child, there is the oldest of all the things that i certainly know.' on another occasion his father is said to have asked the boy, 'what sort of things, do you think, are most alike?' the delicate, blue-eyed boy, after a short pause, replied, 'the leaves of the same tree are most like each other.' 'gather, then, a handful of leaves of that tree,' rejoined the philosopher, 'and choose two that are alike.' the boy failed; but he hid the lesson in his heart, and his thoughts were revealed after many days. these incidents may be trifles; nor should we record them here had not john herschel himself, though singularly reticent about his personal emotions, recorded them as having made a strong impression on his mind. beyond all doubt we can trace therein, first, that grasp and grouping of many things in one, implied in the stone as the oldest of things; and, secondly, that fine and subtle discrimination of each thing out of many like things as forming the main features which characterized the habit of our venerated friend's philosophy." john herschel entered st. john's college, cambridge, when he was seventeen years of age. his university career abundantly fulfilled his father's eager desire, that his only son should develop a capacity for the pursuit of science. after obtaining many lesser distinctions, he finally came out as senior wrangler in 1813. it was, indeed, a notable year in the mathematical annals of the university. second on that list, in which herschel's name was first, appeared that of the illustrious peacock, afterwards dean of ely, who remained throughout life one of herschel's most intimate friends. almost immediately after taking his degree, herschel gave evidence of possessing a special aptitude for original scientific investigation. he sent to the royal society a mathematical paper which was published in the philosophical transactions. doubtless the splendour that attached to the name he bore assisted him in procuring early recognition of his own great powers. certain it is that he was made a fellow of the royal society at the unprecedentedly early age of twenty-one. even after this remarkable encouragement to adopt a scientific career as the business of his life, it does not seem that john herschel at first contemplated devoting himself exclusively to science. he commenced to prepare for the profession of the law by entering as a student at the middle temple, and reading with a practising barrister. but a lawyer john herschel was not destined to become. circumstances brought him into association with some leading scientific men. he presently discovered that his inclinations tended more and more in the direction of purely scientific pursuits. thus it came to pass that the original intention as to the calling which he should follow was gradually abandoned. fortunately for science herschel found its pursuit so attractive that he was led, as his father had been before him, to give up his whole life to the advancement of knowledge. nor was it unnatural that a senior wrangler, who had once tasted the delights of mathematical research, should have been tempted to devote much time to this fascinating pursuit. by the time john herschel was twenty-nine he had published so much mathematical work, and his researches were considered to possess so much merit, that the royal society awarded him the copley medal, which was the highest distinction it was capable of conferring. at the death of his father in 1822, john herschel, with his tastes already formed for a scientific career, found himself in the possession of ample means. to him also passed all his father's great telescopes and apparatus. these material aids, together with a dutiful sense of filial obligation, decided him to make practical astronomy the main work of his life. he decided to continue to its completion that great survey of the heavens which had already been inaugurated, and, indeed, to a large extent accomplished, by his father. the first systematic piece of practical astronomical work which john herschel undertook was connected with the measurement of what are known as "double stars." it should be observed, that there are in the heavens a number of instances in which two stars are seen in very close association. in the case of those objects to which the expression "double stars" is generally applied, the two luminous points are so close together that even though they might each be quite bright enough to be visible to the unaided eye, yet their proximity is such that they cannot be distinguished as two separate objects without optical aid. the two stars seem fused together into one. in the telescope, however, the bodies may be discerned separately, though they are frequently so close together that it taxes the utmost power of the instrument to indicate the division between them. the appearance presented by a double star might arise from the circumstance that the two stars, though really separated from each other by prodigious distances, happened to lie nearly in the same line of vision, as seen from our point of view. no doubt, many of the so-called double stars could be accounted for on this supposition. indeed, in the early days when but few double stars were known, and when telescopes were not powerful enough to exhibit the numerous close doubles which have since been brought to light, there seems to have been a tendency to regard all double stars as merely such perspective effects. it was not at first suggested that there could be any physical connection between the components of each pair. the appearance presented was regarded as merely due to the circumstance that the line joining the two bodies happened to pass near the earth. [plate: sir john herschel.] in the early part of his career, sir william herschel seems to have entertained the view then generally held by other astronomers with regard to the nature of these stellar pairs. the great observer thought that the double stars could therefore be made to afford a means of solving that problem in which so many of the observers of the skies had been engaged, namely, the determination of the distances of the stars from the earth. herschel saw that the displacement of the earth in its annual movement round the sun would produce an apparent shift in the place of the nearer of the two stars relatively to the other, supposed to be much more remote. if this shift could be measured, then the distance of the nearer of the stars could be estimated with some degree of precision. as has not unfrequently happened in the history of science, an effect was perceived of a very different nature from that which had been anticipated. if the relative places of the two stars had been apparently deranged merely in consequence of the motion of the earth, then the phenomenon would be an annual one. after the lapse of a year the two stars would have regained their original relative positions. this was the effect for which william herschel was looking. in certain of the so called double stars, he, no doubt, did find a movement. he detected the remarkable fact that both the apparent distance and the relative positions of the two bodies were changing. but what was his surprise to observe that these alterations were not of an annually periodic character. it became evident then that in some cases one of the component stars was actually revolving around the other, in an orbit which required many years for its completion. here was indeed a remarkable discovery. it was clearly impossible to suppose that movements of this kind could be mere apparent displacements, arising from the annual shift in our point of view, in consequence of the revolution of the earth. herschel's discovery established the interesting fact that, in certain of these double stars, or binary stars, as these particular objects are more expressively designated, there is an actual orbital revolution of a character similar to that which the earth performs around the sun. thus it was demonstrated that in these particular double stars the nearness of the two components was not merely apparent. the objects must actually lie close together at a distance which is small in comparison with the distance at which either of them is separated from the earth. the fact that the heavens contain pairs of twin suns in mutual revolution was thus brought to light. in consequence of this beautiful discovery, the attention of astronomers was directed to the subject of double stars with a degree of interest which these objects had never before excited. it was therefore not unnatural that john herschel should have been attracted to this branch of astronomical work. admiration for his father's discovery alone might have suggested that the son should strive to develop this territory newly opened up to research. but it also happened that the mathematical talents of the younger herschel inclined his inquiries in the same direction. he saw clearly that, when sufficient observations of any particular binary star had been accumulated, it would then be within the power of the mathematician to elicit from those observations the shape and the position in space of the path which each of the revolving stars described around the other. indeed, in some cases he would be able to perform the astonishing feat of determining from his calculations the weight of these distant suns, and thus be enabled to compare them with the mass of our own sun. [plate: nebula in southern hemisphere, drawn by sir john herschel.] but this work must follow the observations, it could not precede them. the first step was therefore to observe and to measure with the utmost care the positions and distances of those particular double stars which appear to offer the greatest promise in this particular research. in 1821, herschel and a friend of his, mr. james south, agreed to work together with this object. south was a medical man with an ardent devotion to science, and possessed of considerable wealth. he procured the best astronomical instruments that money could obtain, and became a most enthusiastic astronomer and a practical observer of tremendous energy. south and john herschel worked together for two years in the observation and measurement of the double stars discovered by sir william herschel. in the course of this time their assiduity was rewarded by the accumulation of so great a mass of careful measurements that when published, they formed quite a volume in the "philosophical transactions." the value and accuracy of the work, when estimated by standards which form proper criteria for that period, is universally recognised. it greatly promoted the progress of sidereal astronomy, and the authors were in consequence awarded medals from the royal society, and the royal astronomical society, as well as similar testimonials from various foreign institutions. this work must, however, be regarded as merely introductory to the main labours of john herschel's life. his father devoted the greater part of his years as an observer to what he called his "sweeps" of the heavens. the great reflecting telescope, twenty feet long, was moved slowly up and down through an arc of about two degrees towards and from the pole, while the celestial panorama passed slowly in the course of the diurnal motion before the keenly watching eye of the astronomer. whenever a double star traversed the field herschel described it to his sister caroline, who, as we have already mentioned, was his invariable assistant in his midnight watches. when a nebula appeared, then he estimated its size and its brightness, he noticed whether it had a nucleus, or whether it had stars disposed in any significant manner with regard to it. he also dictated any other circumstance which he deemed worthy of record. these observations were duly committed to writing by the same faithful and indefatigable scribe, whose business it also was to take a memorandum of the exact position of the object as indicated by a dial placed in front of her desk, and connected with the telescope. john herschel undertook the important task of re-observing the various double stars and nebulae which had been discovered during these memorable vigils. the son, however, lacked one inestimable advantage which had been possessed by the father. john herschel had no assistant to discharge all those duties which caroline had so efficiently accomplished. he had, therefore, to modify the system of sweeping previously adopted in order to enable all the work both of observing and of recording to be done by himself. this, in many ways, was a great drawback to the work of the younger astronomer. the division of labour between the observer and the scribe enables a greatly increased quantity of work to be got through. it is also distinctly disadvantageous to an observer to have to use his eye at the telescope directly after he has been employing it for reading the graduations on a circle, by the light of a lamp, or for entering memoranda in a note book. nebulae, especially, are often so excessively faint that they can only be properly observed by an eye which is in that highly sensitive condition which is obtained by long continuance in darkness. the frequent withdrawal of the eye from the dark field of the telescope, and the application of it to reading by artificial light, is very prejudicial to its use for the more delicate purpose. john herschel, no doubt, availed himself of every precaution to mitigate the ill effects of this inconvenience as much as possible, but it must have told upon his labours as compared with those of his father. but nevertheless john herschel did great work during his "sweeps." he was specially particular to note all the double stars which presented themselves to his observation. of course some little discretion must be allowed in deciding as to what degree of proximity in adjacent stars does actually bring them within the category of "double stars." sir john set down all such objects as seemed to him likely to be of interest, and the results of his discoveries in this branch of astronomy amount to some thousands. six or seven great memoirs in the transactions of the royal astronomical society have been devoted to giving an account of his labours in this department of astronomy. [plate: the cluster in the centaur, drawn by sir john herschel.] one of the achievements by which sir john herschel is best known is his invention of a method by which the orbits of binary stars could be determined. it will be observed that when one star revolves around another in consequence of the law of gravitation, the orbit described must be an ellipse. this ellipse, however, generally speaking, appears to us more or less foreshortened, for it is easily seen that only under highly exceptional circumstances would the plane in which the stars move happen to be directly square to the line of view. it therefore follows that what we observe is not exactly the track of one star around the other; it is rather the projection of that track as seen on the surface of the sky. now it is remarkable that this apparent path is still an ellipse. herschel contrived a very ingenious and simple method by which he could discover from the observations the size and position of the ellipse in which the revolution actually takes place. he showed how, from the study of the apparent orbit of the star, and from certain measurements which could easily be effected upon it, the determination of the true ellipse in which the movement is performed could be arrived at. in other words, herschel solved in a beautiful manner the problem of finding the true orbits of double stars. the importance of this work may be inferred from the fact that it has served as the basis on which scores of other investigators have studied the fascinating subject of the movement of binary stars. the labours, both in the discovery and measurement of the double stars, and in the discussion of the observations with the object of finding the orbits of such stars as are in actual revolution, received due recognition in yet another gold medal awarded by the royal society. an address was delivered on the occasion by the duke of sussex (30th november, 1833), in the course of which, after stating that the medal had been conferred on sir john herschel, he remarks:-"it has been said that distance of place confers the same privilege as distance of time, and i should gladly avail myself of the privilege which is thus afforded me by sir john herschel's separation from his country and friends, to express my admiration of his character in stronger terms than i should otherwise venture to use; for the language of panegyric, however sincerely it may flow from the heart, might be mistaken for that of flattery, if it could not thus claim somewhat of an historical character; but his great attainments in almost every department of human knowledge, his fine powers as a philosophical writer, his great services and his distinguished devotion to science, the high principles which have regulated his conduct in every relation of life, and, above all, his engaging modesty, which is the crown of all his other virtues, presenting such a model of an accomplished philosopher as can rarely be found beyond the regions of fiction, demand abler pens than mine to describe them in adequate terms, however much inclined i might feel to undertake the task." the first few lines of the eulogium just quoted allude to herschel's absence from england. this was not merely an episode of interest in the career of herschel, it was the occasion of one of the greatest scientific expeditions in the whole history of astronomy. herschel had, as we have seen, undertaken a revision of his father's "sweeps" for new objects, in those skies which are visible from our latitudes in the northern hemisphere. he had well-nigh completed this task. zone by zone the whole of the heavens which could be observed from windsor had passed under his review. he had added hundreds to the list of nebulae discovered by his father. he had announced thousands of double stars. at last, however, the great survey was accomplished. the contents of the northern hemisphere, so far at least as they could be disclosed by his telescope of twenty feet focal length, had been revealed. [plate: sir john herschel's observatory at feldhausen, cape of good hope.] but herschel felt that this mighty task had to be supplemented by another of almost equal proportions, before it could be said that the twenty-foot telescope had done its work. it was only the northern half of the celestial sphere which had been fully explored. the southern half was almost virgin territory, for no other astronomer was possessed of a telescope of such power as those which the herschels had used. it is true, of course, that as a certain margin of the southern hemisphere was visible from these latitudes, it had been more or less scrutinized by observers in northern skies. and the glimpses which had thus been obtained of the celestial objects in the southern sky, were such as to make an eager astronomer long for a closer acquaintance with the celestial wonders of the south. the most glorious object in the sidereal heavens, the great nebula in orion, lies indeed in that southern hemisphere to which the younger herschel's attention now became directed. it fortunately happens, however, for votaries of astronomy all the world over, that nature has kindly placed her most astounding object, the great nebula in orion, in such a favoured position, near the equator, that from a considerable range of latitudes, both north and south, the wonders of the nebula can be explored. there are grounds for thinking that the southern heavens contain noteworthy objects which, on the whole, are nearer to the solar system than are the noteworthy objects in the northern skies. the nearest star whose distance is known, alpha centauri, lies in the southern hemisphere, and so also does the most splendid cluster of stars. influenced by the desire to examine these objects, sir john herschel determined to take his great telescope to a station in the southern hemisphere, and thus complete his survey of the sidereal heavens. the latitude of the cape of good hope is such that a suitable site could be there found for his purpose. the purity of the skies in south africa promised to provide for the astronomer those clear nights which his delicate task of surveying the nebulae would require. on november 13, 1833, sir john herschel, who had by this time received the honour of knighthood from william iv., sailed from portsmouth for the cape of good hope, taking with him his gigantic instruments. after a voyage of two months, which was considered to be a fair passage in those days, he landed in table bay, and having duly reconnoitred various localities, he decided to place his observatory at a place called feldhausen, about six miles from cape town, near the base of the table mountain. a commodious residence was there available, and in it he settled with his family. a temporary building was erected to contain the equatorial, but the great twenty-foot telescope was accommodated with no more shelter than is provided by the open canopy of heaven. as in his earlier researches at home, the attention of the great astronomer at the cape of good hope was chiefly directed to the measurement of the relative positions and distances apart of the double stars, and to the close examination of the nebulae. in the delineation of the form of these latter objects herschel found ample employment for his skilful pencil. many of the drawings he has made of the celestial wonders in the southern sky are admirable examples of celestial portraiture. the number of the nebulae and of those kindred objects, the star clusters, which herschel studied in the southern heavens, during four years of delightful labour, amount in all to one thousand seven hundred and seven. his notes on their appearance, and the determinations of their positions, as well as his measurements of double stars, and much other valuable astronomical research, were published in a splendid volume, brought out at the cost of the duke of northumberland. this is, indeed, a monumental work, full of interesting and instructive reading for any one who has a taste for astronomy. herschel had the good fortune to be at the cape on the occasion of the periodical return of halley's great comet in 1833. to the study of this body he gave assiduous attention, and the records of his observations form one of the most interesting chapters in that remarkable volume to which we have just referred. [plate: column at feldhausen, cape town, to commemorate sir john herschel's survey of the southern heavens.] early in 1838 sir john herschel returned to england. he had made many friends at the cape, who deeply sympathised with his selfimposed labours while he was resident among them. they desired to preserve the recollection of this visit, which would always, they considered, be a source of gratification in the colony. accordingly, a number of scientific friends in that part of the world raised a monument with a suitable inscription, on the spot which had been occupied by the great twenty-foot reflector at feldhausen. his return to england after five years of absence was naturally an occasion for much rejoicing among the lovers of astronomy. he was entertained at a memorable banquet, and the queen, at her coronation, made him a baronet. his famous aunt caroline, at that time aged eighty, was still in the enjoyment of her faculties, and was able to estimate at its true value the further lustre which was added to the name she bore. but there is reason to believe that her satisfaction was not quite unmixed with other feelings. with whatever favour she might regard her nephew, he was still not the brother to whom her life had been devoted. so jealous was this vigorous old lady of the fame of the great brother william, that she could hardly hear with patience of the achievements of any other astronomer, and this failing existed in some degree even when that other astronomer happened to be her illustrious nephew. with sir john herschel's survey of the southern hemisphere it may be said that his career as an observing astronomer came to a close. he did not again engage in any systematic telescopic research. but it must not be inferred from this statement that he desisted from active astronomical work. it has been well observed that sir john herschel was perhaps the only astronomer who has studied with success, and advanced by original research, every department of the great science with which his name is associated. it was to some other branches of astronomy besides those concerned with looking through telescopes, that the rest of the astronomer's life was to be devoted. to the general student sir john herschel is best known by the volume which he published under the title of "outlines of astronomy." this is, indeed, a masterly work, in which the characteristic difficulties of the subject are resolutely faced and expounded with as much simplicity as their nature will admit. as a literary effort this work is admirable, both on account of its picturesque language and the ennobling conceptions of the universe which it unfolds. the student who desires to become acquainted with those recondite departments of astronomy, in which the effects of the disturbing action of one planet upon the motions of another planet are considered, will turn to the chapters in herschel's famous work on the subject. there he will find this complex matter elucidated, without resort to difficult mathematics. edition after edition of this valuable work has appeared, and though the advances of modern astronomy have left it somewhat out of date in certain departments, yet the expositions it contains of the fundamental parts of the science still remain unrivalled. another great work which sir john undertook after his return from the cape, was a natural climax to those labours on which his father and he had been occupied for so many years. we have already explained how the work of both these observers had been mainly devoted to the study of the nebulae and the star clusters. the results of their discoveries had been announced to the world in numerous isolated memoirs. the disjointed nature of these publications made their use very inconvenient. but still it was necessary for those who desired to study the marvellous objects discovered by the herschels, to have frequent recourse to the original works. to incorporate all the several observations of nebular into one great systematic catalogue, seemed, therefore, to be an indispensable condition of progress in this branch of knowledge. no one could have been so fitted for this task as sir john herschel. he, therefore, attacked and carried through the great undertaking. thus at last a grand catalogue of nebulae and clusters was produced. never before was there so majestic an inventory. if we remember that each of the nebulae is an object so vast, that the whole of the solar system would form an inconsiderable speck by comparison, what are we to think of a collection in which these objects are enumerated in thousands? in this great catalogue we find arranged in systematic order all the nebulae and all the clusters which had been revealed by the diligence of the herschels, father and son, in the northern hemisphere, and of the son alone in the southern hemisphere. nor should we omit to mention that the labours of other astronomers were likewise incorporated. it was unavoidable that the descriptions given to each of the objects should be very slight. abbreviations are used, which indicate that a nebula is bright, or very bright, or extremely bright, or faint, or very faint, or extremely faint. such phrases have certainly but a relative and technical meaning in such a catalogue. the nebulae entered as extremely bright by the experienced astronomer are only so described by way of contrast to the great majority of these delicate telescopic objects. most of the nebulae, indeed, are so difficult to see, that they admit of but very slight description. it should be observed that herschel's catalogue augmented the number of known nebulous objects to more than ten times that collected into any catalogue which had ever been compiled before the days of william herschel's observing began. but the study of these objects still advances, and the great telescopes now in use could probably show at least twice as many of these objects as are contained in the list of herschel, of which a new and enlarged edition has since been brought out by dr. dreyer. one of the best illustrations of sir john herschel's literary powers is to be found in the address which he delivered at the royal astronomical society, on the occasion of presenting a medal to mr. francis baily, in recognition of his catalogue of stars. the passage i shall here cite places in its proper aspect the true merit of the laborious duty involved in such a task as that which mr. baily had carried through with such success:-"if we ask to what end magnificent establishments are maintained by states and sovereigns, furnished with masterpieces of art, and placed under the direction of men of first-rate talent and high-minded enthusiasm, sought out for those qualities among the foremost in the ranks of science, if we demand qui bono? for what good a bradley has toiled, or a maskelyne or a piazzi has worn out his venerable age in watching, the answer is--not to settle mere speculative points in the doctrine of the universe; not to cater for the pride of man by refined inquiries into the remoter mysteries of nature; not to trace the path of our system through space, or its history through past and future eternities. these, indeed, are noble ends and which i am far from any thought of depreciating; the mind swells in their contemplation, and attains in their pursuit an expansion and a hardihood which fit it for the boldest enterprise. but the direct practical utility of such labours is fully worthy of their speculative grandeur. the stars are the landmarks of the universe; and, amidst the endless and complicated fluctuations of our system, seem placed by its creator as guides and records, not merely to elevate our minds by the contemplation of what is vast, but to teach us to direct our actions by reference to what is immutable in his works. it is, indeed, hardly possible to over-appreciate their value in this point of view. every well-determined star, from the moment its place is registered, becomes to the astronomer, the geographer, the navigator, the surveyor, a point of departure which can never deceive or fail him, the same for ever and in all places, of a delicacy so extreme as to be a test for every instrument yet invented by man, yet equally adapted for the most ordinary purposes; as available for regulating a town clock as for conducting a navy to the indies; as effective for mapping down the intricacies of a petty barony as for adjusting the boundaries of transatlantic empires. when once its place has been thoroughly ascertained and carefully recorded, the brazen circle with which that useful work was done may moulder, the marble pillar may totter on its base, and the astronomer himself survive only in the gratitude of posterity; but the record remains, and transfuses all its own exactness into every determination which takes it for a groundwork, giving to inferior instruments--nay, even to temporary contrivances, and to the observations of a few weeks or days--all the precision attained originally at the cost of so much time, labour, and expense." sir john herschel wrote many other works besides those we have mentioned. his "treatise on meteorology" is, indeed, a standard work on this subject, and numerous articles from the same pen on miscellaneous subjects, which have been collected and reprinted, seemed as a relaxation from his severe scientific studies. like certain other great mathematicians herschel was also a poet, and he published a translation of the iliad into blank verse. in his later years sir john herschel lived a retired life. for a brief period he had, indeed, been induced to accept the office of master of the mint. it was, however, evident that the routine of such an occupation was not in accordance with his tastes, and he gladly resigned it, to return to the seclusion of his study in his beautiful home at collingwood, in kent. his health having gradually failed, he died on the 11th may, 1871, in the seventy-ninth year of his age. the earl of rosse. the subject of our present sketch occupies quite a distinct position in scientific history. unlike many others who have risen by their scientific discoveries from obscurity to fame, the great earl of rosse was himself born in the purple. his father, who, under the title of sir lawrence parsons, had occupied a distinguished position in the irish parliament, succeeded on the death of his father to the earldom which had been recently created. the subject of our present memoir was, therefore, the third of the earls of rosse, and he was born in york on june 17, 1800. prior to his father's death in 1841, he was known as lord oxmantown. the university education of the illustrious astronomer was begun in dublin and completed at oxford. we do not hear in his case of any very remarkable university career. lord rosse was, however, a diligent student, and obtained a first-class in mathematics. he always took a great deal of interest in social questions, and was a profound student of political economy. he had a seat in the house of commons, as member for king's county, from 1821 to 1834, his ancestral estate being situated in this part of ireland. [plate: the earl of rosse.] lord rosse was endowed by nature with a special taste for mechanical pursuits. not only had he the qualifications of a scientific engineer, but he had the manual dexterity which qualified him personally to carry out many practical arts. lord rosse was, in fact, a skilful mechanic, an experienced founder, and an ingenious optician. his acquaintances were largely among those who were interested in mechanical pursuits, and it was his delight to visit the works or engineering establishments where refined processes in the arts were being carried on. it has often been stated--and as i have been told by members of his family, truly stated--that on one occasion, after he had been shown over some large works in the north of england, the proprietor bluntly said that he was greatly in want of a foreman, and would indeed be pleased if his visitor, who had evinced such extraordinary capacity for mechanical operations, would accept the post. lord rosse produced his card, and gently explained that he was not exactly the right man, but he appreciated the compliment, and this led to a pleasant dinner, and was the basis of a long friendship. i remember on one occasion hearing lord rosse explain how it was that he came to devote his attention to astronomy. it appears that when he found himself in the possession of leisure and of means, he deliberately cast around to think how that means and that leisure could be most usefully employed. nor was it surprising that he should search for a direction which would offer special scope for his mechanical tastes. he came to the conclusion that the building of great telescopes was an art which had received no substantial advance since the great days of william herschel. he saw that to construct mighty instruments for studying the heavens required at once the command of time and the command of wealth, while he also felt that this was a subject the inherent difficulties of which would tax to the uttermost whatever mechanical skill he might possess. thus it was he decided that the construction of great telescopes should become the business of his life. [plate: birr castle. plate: the mall, parsonstown.] in the centre of ireland, seventy miles from dublin, on the border between king's county and tipperary, is a little town whereof we must be cautious before writing the name. the inhabitants of that town frequently insist that its name is birr, * while the official designation is parsonstown, and to this day for every six people who apply one name to the town, there will be half a dozen who use the other. but whichever it may be, birr or parsonstown--and i shall generally call it by the latter name--it is a favourable specimen of an irish county town. the widest street is called the oxmantown mall. it is bordered by the dwelling-houses of the chief residents, and adorned with rows of stately trees. at one end of this distinctly good feature in the town is the parish church, while at the opposite end are the gates leading into birr castle, the ancestral home of the house of parsons. passing through the gates the visitor enters a spacious demesne, possessing much beauty of wood and water, one of the most pleasing features being the junction of the two rivers, which unite at a spot ornamented by beautiful timber. at various points illustrations of the engineering skill of the great earl will be observed. the beauty of the park has been greatly enhanced by the construction of an ample lake, designed with the consummate art by which art is concealed. even in mid-summer it is enlivened by troops of wild ducks preening themselves in that confidence which they enjoy in those happy localities where the sound of a gun is seldom heard. the water is led into the lake by a tube which passes under one of the two rivers just mentioned, while the overflow from the lake turns a water-wheel, which works a pair of elevators ingeniously constructed for draining the low-lying parts of the estate. * considering the fame acquired by parsonstown from lord rosse's mirrors, it may be interesting to note the following extract from "the natural history of ireland," by dr. gerard boate, thomas molyneux m.d., f.r.s., and others, which shows that 150 years ago parsonstown was famous for its glass:- "we shall conclude this chapter with the glass, there having been several glasshouses set up by the english in ireland, none in dublin or other cities, but all of them in the country; amongst which the principal was that of birre, a market town, otherwise called parsonstown, after one sir lawrence parsons, who, having purchased that lordship, built a goodly house upon it; his son william parsons having succeeded him in the possession of it; which town is situate in queen's county, about fifty miles (irish) to the southwest of dublin, upon the borders of the two provinces of leinster and munster; from this place dublin was furnished with all sorts of window and drinking glasses, and such other as commonly are in use. one part of the materials, viz., the sand, they had out of england; the other, to wit the ashes, they made in the place of ash-tree, and used no other. the chiefest difficulty was to get the clay for the pots to melt the materials in; this they had out of the north."--chap. xxi., sect. viii. "of the glass made in ireland." birr castle itself is a noble mansion with reminiscences from the time of cromwell. it is surrounded by a moat and a drawbridge of modern construction, and from its windows beautiful views can be had over the varied features of the park. but while the visitors to parsonstown will look with great interest on this residence of an irish landlord, whose delight it was to dwell in his own country, and among his own people, yet the feature which they have specially come to observe is not to be found in the castle itself. on an extensive lawn, sweeping down from the moat towards the lake, stand two noble masonry walls. they are turreted and clad with ivy, and considerably loftier than any ordinary house. as the visitor approaches, he will see between those walls what may at first sight appear to him to be the funnel of a steamer lying down horizontally. on closer approach he will find that it is an immense wooden tube, sixty feet long, and upwards of six feet in diameter. it is in fact large enough to admit of a tall man entering into it and walking erect right through from one end to the other. this is indeed the most gigantic instrument which has ever been constructed for the purpose of exploring the heavens. closely adjoining the walls between which the great tube swings, is a little building called "the observatory." in this the smaller instruments are contained, and there are kept the books which are necessary for reference. the observatory also offers shelter to the observers, and provides the bright fire and the cup of warm tea, which are so acceptable in the occasional intervals of a night's observation passed on the top of the walls with no canopy but the winter sky. almost the first point which would strike the visitor to lord rosse's telescope is that the instrument at which he is looking is not only enormously greater than anything of the kind that he has ever seen before, but also that it is something of a totally different nature. in an ordinary telescope he is accustomed to find a tube with lenses of glass at either end, while the large telescopes that we see in our observatories are also in general constructed on the same principle. at one end there is the object-glass, and at the other end the eye-piece, and of course it is obvious that with an instrument of this construction it is to the lower end of the tube that the eye of the observer must be placed when the telescope is pointed to the skies. but in lord rosse's telescope you would look in vain for these glasses, and it is not at the lower end of the instrument that you are to take your station when you are going to make your observations. the astronomer at parsonstown has rather to avail himself of the ingenious system of staircases and galleries, by which he is enabled to obtain access to the mouth of the great tube. the colossal telescope which swings between the great walls, like herschel's great telescope already mentioned, is a reflector, the original invention of which is due of course to newton. the optical work which is accomplished by the lenses in the ordinary telescope is effected in the type of instrument constructed by lord rosse by a reflecting mirror which is placed at the lower end of the vast tube. the mirror in this instrument is made of a metal consisting of two parts of copper to one of tin. as we have already seen, this mixture forms an alloy of a very peculiar nature. the copper and the tin both surrender their distinctive qualities, and unite to form a material of a very different physical character. the copper is tough and brown, the tin is no doubt silvery in hue, but soft and almost fibrous in texture. when the two metals are mixed together in the proportions i have stated, the alloy obtained is intensely hard and quite brittle being in both these respects utterly unlike either of the two ingredients of which it is composed. it does, however, resemble the tin in its whiteness, but it acquires a lustre far brighter than tin; in fact, this alloy hardly falls short of silver itself in its brilliance when polished. [plate: lord rosse's telescope. from a photograph by w. lawrence, upper sackville street, dublin.] the first duty that lord rosse had to undertake was the construction of this tremendous mirror, six feet across, and about four or five inches thick. the dimensions were far in excess of those which had been contemplated in any previous attempt of the same kind. herschel had no doubt fashioned one mirror of four feet in diameter, and many others of smaller dimensions, but the processes which he employed had never been fully published, and it was obvious that, with a large increase in dimensions, great additional difficulties had to be encountered. difficulties began at the very commencement of the process, and were experienced in one form or another at every subsequent stage. in the first place, the mere casting of a great disc of this mixture of tin and copper, weighing something like three or four tons, involved very troublesome problems. no doubt a casting of this size, if the material had been, for example, iron, would have offered no difficulties beyond those with which every practical founder is well acquainted, and which he has to encounter daily in the course of his ordinary work. but speculum metal is a material of a very intractable description. there is, of course, no practical difficulty in melting the copper, nor in adding the proper proportion of tin when the copper has been melted. there may be no great difficulty in arranging an organization by which several crucibles, filled with the molten material, shall be poured simultaneously so as to obtain the requisite mass of metal, but from this point the difficulties begin. for speculum metal when cold is excessively brittle, and were the casting permitted to cool like an ordinary copper or iron casting, the mirror would inevitably fly into pieces. lord rosse, therefore, found it necessary to anneal the casting with extreme care by allowing it to cool very slowly. this was accomplished by drawing the disc of metal as soon as it had entered into the solid state, though still glowing red, into an annealing oven. there the temperature was allowed to subside so gradually, that six weeks elapsed before the mirror had reached the temperature of the external air. the necessity for extreme precaution in the operation of annealing will be manifest if we reflect on one of the accidents which happened. on a certain occasion, after the cooling of a great casting had been completed, it was found, on withdrawing the speculum, that it was cracked into two pieces. this mishap was eventually traced to the fact that one of the walls of the oven had only a single brick in its thickness, and that therefore the heat had escaped more easily through that side than through the other sides which were built of double thickness. the speculum had, consequently, not cooled uniformly, and hence the fracture had resulted. undeterred, however, by this failure, as well as by not a few other difficulties, into a description of which we cannot now enter, lord rosse steadily adhered to his self-imposed task, and at last succeeded in casting two perfect discs on which to commence the tedious processes of grinding and polishing. the magnitude of the operations involved may perhaps be appreciated if i mention that the value of the mere copper and tin entering into the composition of each of the mirrors was about 500 pounds. in no part of his undertaking was lord rosse's mechanical ingenuity more taxed than in the devising of the mechanism for carrying out the delicate operations of grinding and polishing the mirrors, whose casting we have just mentioned. in the ordinary operations of the telescope-maker, such processes had hitherto been generally effected by hand, but, of course, such methods became impossible when dealing with mirrors which were as large as a good-sized dinner table, and whose weight was measured by tons. the rough grinding was effected by means of a tool of cast iron about the same size as the mirror, which was moved by suitable machinery both backwards and forwards, and round and round, plenty of sand and water being supplied between the mirror and the tool to produce the necessary attrition. as the process proceeded and as the surface became smooth, emery was used instead of sand; and when this stage was complete, the grinding tool was removed and the polishing tool was substituted. the essential part of this was a surface of pitch, which, having been temporarily softened by heat, was then placed on the mirror, and accepted from the mirror the proper form. rouge was then introduced as the polishing powder, and the operation was continued about nine hours, by which time the great mirror had acquired the appearance of highly polished silver. when completed, the disc of speculum metal was about six feet across and four inches thick. the depression in the centre was about half an inch. mounted on a little truck, the great speculum was then conveyed to the instrument, to be placed in its receptacle at the bottom of the tube, the length of which was sixty feet, this being the focal distance of the mirror. another small reflector was inserted in the great tube sideways, so as to direct the gaze of the observer down upon the great reflector. thus was completed the most colossal instrument for the exploration of the heavens which the art of man has ever constructed. [plate: roman catholic church at parsonstown.] it was once my privilege to be one of those to whom the illustrious builder of the great telescope entrusted its use. for two seasons in 1865 and 1866 i had the honour of being lord rosse's astronomer. during that time i passed many a fine night in the observer's gallery, examining different objects in the heavens with the aid of this remarkable instrument. at the time i was there, the objects principally studied were the nebulae, those faint stains of light which lie on the background of the sky. lord rosse's telescope was specially suited for the scrutiny of these objects, inasmuch as their delicacy required all the light-grasping power which could be provided. one of the greatest discoveries made by lord rosse, when his huge instrument was first turned towards the heavens, consisted in the detection of the spiral character of some of the nebulous forms. when the extraordinary structure of these objects was first announced, the discovery was received with some degree of incredulity. other astronomers looked at the same objects, and when they failed to discern--and they frequently did fail to discern--the spiral structure which lord rosse had indicated, they drew the conclusion that this spiral structure did not exist. they thought it must be due possibly to some instrumental defect or to the imagination of the observer. it was, however, hardly possible for any one who was both willing and competent to examine into the evidence, to doubt the reality of lord rosse's discoveries. it happens, however, that they have been recently placed beyond all doubt by testimony which it is impossible to gainsay. a witness never influenced by imagination has now come forward, and the infallible photographic plate has justified lord rosse. among the remarkable discoveries which dr. isaac roberts has recently made in the application of his photographic apparatus to the heavens, there is none more striking than that which declares, not only that the nebulae which lord rosse described as spirals, actually do possess the character so indicated, but that there are many others of the same description. he has even brought to light the astonishingly interesting fact that there are invisible objects of this class which have never been seen by human eye, but whose spiral character is visible to the peculiar delicacy of the photographic telescope. in his earlier years, lord rosse himself used to be a diligent observer of the heavenly bodies with the great telescope which was completed in the year 1845. but i think that those who knew lord rosse well, will agree that it was more the mechanical processes incidental to the making of the telescope which engaged his interest than the actual observations with the telescope when it was completed. indeed one who was well acquainted with him believed lord rosse's special interest in the great telescope ceased when the last nail had been driven into it. but the telescope was never allowed to lie idle, for lord rosse always had associated with him some ardent young astronomer, whose delight it was to employ to the uttermost the advantages of his position in exploring the wonders of the sky. among those who were in this capacity in the early days of the great telescope, i may mention my esteemed friend dr. johnston stoney. such was the renown of lord rosse himself, brought about by his consummate mechanical genius and his astronomical discoveries, and such the interest which gathered around the marvellous workshops at birr castle, wherein his monumental exhibitions of optical skill were constructed, that visitors thronged to see him from all parts of the world. his home at parsonstown became one of the most remarkable scientific centres in great britain; thither assembled from time to time all the leading men of science in the country, as well as many illustrious foreigners. for many years lord rosse filled with marked distinction the exalted position of president of the royal society, and his advice and experience in practical mechanical matters were always at the disposal of those who sought his assistance. personally and socially lord rosse endeared himself to all with whom he came in contact. i remember one of the attendants telling me that on one occasion he had the misfortune to let fall and break one of the small mirrors on which lord rosse had himself expended many hours of hard personal labour. the only remark of his lordship was that "accidents will happen." the latter years of his life lord rosse passed in comparative seclusion; he occasionally went to london for a brief sojourn during the season, and he occasionally went for a cruise in his yacht; but the greater part of the year he spent at birr castle, devoting himself largely to the study of political and social questions, and rarely going outside the walls of his demesne, except to church on sunday mornings. he died on october 31, 1867. he was succeeded by his eldest son, the present earl of rosse, who has inherited his father's scientific abilities, and done much notable work with the great telescope. airy. in our sketch of the life of flamsteed, we have referred to the circumstances under which the famous observatory that crowns greenwich hill was founded. we have also had occasion to mention that among the illustrious successors of flamsteed both halley and bradley are to be included. but a remarkable development of greenwich observatory from the modest establishment of early days took place under the direction of the distinguished astronomer whose name is at the head of this chapter. by his labours this temple of science was organised to such a degree of perfection that it has served in many respects as a model for other astronomical establishments in various parts of the world. an excellent account of airy's career has been given by professor h. h. turner, in the obituary notice published by the royal astronomical society. to this i am indebted for many of the particulars here to be set down concerning the life of the illustrious astronomer royal. the family from which airy took his origin came from kentmere, in westmoreland. his father, william airy, belonged to a lincolnshire branch of the same stock. his mother's maiden name was ann biddell, and her family resided at playford, near ipswich. william airy held some small government post which necessitated an occasional change of residence to different parts of the country, and thus it was that his son, george biddell, came to be born at alnwick, on 27th july, 1801. the boy's education, so far as his school life was concerned was partly conducted at hereford and partly at colchester. he does not, however, seem to have derived much benefit from the hours which he passed in the schoolroom. but it was delightful to him to spend his holidays on the farm at playford, where his uncle, arthur biddell, showed him much kindness. the scenes of his early youth remained dear to airy throughout his life, and in subsequent years he himself owned a house at playford, to which it was his special delight to resort for relaxation during the course of his arduous career. in spite of the defects of his school training he seems to have manifested such remarkable abilities that his uncle decided to enter him in cambridge university. he accordingly joined trinity college as a sizar in 1819, and after a brilliant career in mathematical and physical science he graduated as senior wrangler in 1823. it may be noted as an exceptional circumstance that, notwithstanding the demands on his time in studying for his tripos, he was able, after his second term of residence, to support himself entirely by taking private pupils. in the year after he had taken his degree he was elected to a fellowship at trinity college. having thus gained an independent position, airy immediately entered upon that career of scientific work which he prosecuted without intermission almost to the very close of his life. one of his most interesting researches in these early days is on the subject of astigmatism, which defect he had discovered in his own eyes. his investigations led him to suggest a means of correcting this defect by using a pair of spectacles with lenses so shaped as to counteract the derangement which the astigmatic eye impressed upon the rays of light. his researches on this subject were of a very complete character, and the principles he laid down are to the present day practically employed by oculists in the treatment of this malformation. on the 7th of december, 1826, airy was elected to the lucasian professorship of mathematics in the university of cambridge, the chair which newton's occupancy had rendered so illustrious. his tenure of this office only lasted for two years, when he exchanged it for the plumian professorship. the attraction which led him to desire this change is doubtless to be found in the circumstance that the plumian professorship of astronomy carried with it at that time the appointment of director of the new astronomical observatory, the origin of which must now be described. those most interested in the scientific side of university life decided in 1820 that it would be proper to found an astronomical observatory at cambridge. donations were accordingly sought for this purpose, and upwards of 6,000 pounds were contributed by members of the university and the public. to this sum 5,000 pounds were added by a grant from the university chest, and in 1824 further sums amounting altogether to 7,115 pounds were given by the university for the same object. the regulations as to the administration of the new observatory placed it under the management of the plumian professor, who was to be provided with two assistants. their duties were to consist in making meridian observations of the sun, moon, and the stars, and the observations made each year were to be printed and published. the observatory was also to be used in the educational work of the university, for it was arranged that smaller instruments were to be provided by which students could be instructed in the practical art of making astronomical observations. the building of the cambridge astronomical observatory was completed in 1824, but in 1828, when airy entered on the discharge of his duties as director, the establishment was still far from completion, in so far as its organisation was concerned. airy commenced his work so energetically that in the next year after his appointment he was able to publish the first volume of "cambridge astronomical observations," notwithstanding that every part of the work, from the making of observations to the revising of the proof-sheets, had to be done by himself. it may here be remarked that these early volumes of the publications of the cambridge observatory contained the first exposition of those systematic methods of astronomical work which airy afterwards developed to such a great extent at greenwich, and which have been subsequently adopted in many other places. no more profitable instruction for the astronomical beginner can be found than that which can be had by the study of these volumes, in which the plumian professor has laid down with admirable clearness the true principles on which meridian work should be conducted. [plate: sir george airy. from a photograph by mr. e.p. adams, greenwich.] airy gradually added to the instruments with which the observatory was originally equipped. a mural circle was mounted in 1832, and in the same year a small equatorial was erected by jones. this was made use of by airy in a well-known series of observations of jupiter's fourth satellite for the determination of the mass of the great planet. his memoir on this subject fully ex pounds the method of finding the weight of a planet from observations of the movements of a satellite by which the planet is attended. this is, indeed, a valuable investigation which no student of astronomy can afford to neglect. the ardour with which airy devoted himself to astronomical studies may be gathered from a remarkable report on the progress of astronomy during the present century, which he communicated to the british association at its second meeting in 1832. in the early years of his life at cambridge his most famous achievement was connected with a research in theoretical astronomy for which consummate mathematical power was required. we can only give a brief account of the subject, for to enter into any full detail with regard to it would be quite out of the question. venus is a planet of about the same size and the same weight as the earth, revolving in an orbit which lies within that described by our globe. venus, consequently, takes less time than the earth to accomplish one revolution round the sun, and it happens that the relative movements of venus and the earth are so proportioned that in the time in which our earth accomplishes eight of her revolutions the other planet will have accomplished almost exactly thirteen. it, therefore, follows that if the earth and venus are in line with the sun at one date, then in eight years later both planets will again be found at the same points in their orbits. in those eight years the earth has gone round eight times, and has, therefore, regained its original position, while in the same period venus has accomplished thirteen complete revolutions, and, therefore, this planet also has reached the same spot where it was at first. venus and the earth, of course, attract each other, and in consequence of these mutual attractions the earth is swayed from the elliptic track which it would otherwise pursue. in like manner venus is also forced by the attraction of the earth to revolve in a track which deviates from that which it would otherwise follow. owing to the fact that the sun is of such preponderating magnitude (being, in fact, upwards of 300,000 times as heavy as either venus or the earth), the disturbances induced in the motion of either planet, in consequence of the attraction of the other, are relatively insignificant to the main controlling agency by which each of the movements is governed. it is, however, possible under certain circumstances that the disturbing effects produced upon one planet by the other can become so multiplied as to produce peculiar effects which attain measurable dimensions. suppose that the periodic times in which the earth and venus revolved had no simple relation to each other, then the points of their tracks in which the two planets came into line with the sun would be found at different parts of the orbits, and consequently the disturbances would to a great extent neutralise each other, and produce but little appreciable effect. as, however, venus and the earth come back every eight years to nearly the same positions at the same points of their track, an accumulative effect is produced. for the disturbance of one planet upon the other will, of course, be greatest when those two planets are nearest, that is, when they lie in line with the sun and on the same side of it. every eight years a certain part of the orbit of the earth is, therefore, disturbed by the attraction of venus with peculiar vigour. the consequence is that, owing to the numerical relation between the movements of the planets to which i have referred, disturbing effects become appreciable which would otherwise be too small to permit of recognition. airy proposed to himself to compute the effects which venus would have on the movement of the earth in consequence of the circumstance that eight revolutions of the one planet required almost the same time as thirteen revolutions of the other. this is a mathematical inquiry of the most arduous description, but the plumian professor succeeded in working it out, and he had, accordingly, the gratification of announcing to the royal society that he had detected the influence which venus was thus able to assert on the movement of our earth around the sun. this remarkable investigation gained for its author the gold medal of the royal astronomical society in the year 1832. in consequence of his numerous discoveries, airy's scientific fame had become so well recognised that the government awarded him a special pension, and in 1835, when pond, who was then astronomer royal, resigned, airy was offered the post at greenwich. there was in truth, no scientific inducement to the plumian professor to leave the comparatively easy post he held at cambridge, in which he had ample leisure to devote himself to those researches which specially interested him, and accept that of the much more arduous observatory at greenwich. there were not even pecuniary inducements to make the change; however, he felt it to be his duty to accede to the request which the government had made that he would take up the position which pond had vacated, and accordingly airy went to greenwich as astronomer royal on october 1st, 1835. he immediately began with his usual energy to organise the systematic conduct of the business of the national observatory. to realise one of the main characteristics of airy's great work at greenwich, it is necessary to explain a point that might not perhaps be understood without a little explanation by those who have no practical experience in an observatory. in the work of an establishment such as greenwich, an observation almost always consists of a measurement of some kind. the observer may, for instance, be making a measurement of the time at which a star passes across a spider line stretched through the field of view; on another occasion his object may be the measurement of an angle which is read off by examining through a microscope the lines of division on a graduated circle when the telescope is so pointed that the star is placed on a certain mark in the field of view. in either case the immediate result of the astronomical observation is a purely numerical one, but it rarely happens, indeed we may say it never happens, that the immediate numerical result which the observation gives expresses directly the quantity which we are really seeking for. no doubt the observation has been so designed that the quantity we want to find can be obtained from the figures which the measurement gives, but the object sought is not those figures, for there are always a multitude of other influences by which those figures are affected. for example, if an observation were to be perfect, then the telescope with which the observation is made should be perfectly placed in the exact position which it ought to occupy; this is, however, never the case, for no mechanic can ever construct or adjust a telescope so perfectly as the wants of the astronomer demand. the clock also by which we determine the time of the observation should be correct, but this is rarely if ever the case. we have to correct our observations for such errors, that is to say, we have to determine the errors in the positions of our telescopes and the errors in the going of our clocks, and then we have to determine what the observations would have been had our telescopes been absolutely perfect, and had our clocks been absolutely correct. there are also many other matters which have to be attended to in order to reduce our observations so as to obtain from the figures as yielded to the observer at the telescope the actual quantities which it is his object to determine. the work of effecting these reductions is generally a very intricate and laborious matter, so that it has not unfrequently happened that while observations have accumulated in an observatory, yet the tedious duty of reducing these observations has been allowed to fall into arrear. when airy entered on his duties at greenwich he found there an enormous mass of observations which, though implicitly containing materials of the greatest value to astronomers, were, in their unreduced form, entirely unavailable for any useful purpose. he, therefore, devoted himself to coping with the reduction of the observations of his predecessors. he framed systematic methods by which the reductions were to be effected, and he so arranged the work that little more than careful attention to numerical accuracy would be required for the conduct of the operations. encouraged by the admiralty, for it is under this department that greenwich observatory is placed, the astronomer royal employed a large force of computers to deal with the work. by his energy and admirable organisation he managed to reduce an extremely valuable series of planetary observations, and to publish the results, which have been of the greatest importance to astronomical investigation. the astronomer royal was a capable, practical engineer as well as an optician, and he presently occupied himself by designing astronomical instruments of improved pattern, which should replace the antiquated instruments he found in the observatory. in the course of years the entire equipment underwent a total transformation. he ordered a great meridian circle, every part of which may be said to have been formed from his own designs. he also designed the mounting for a fine equatorial telescope worked by a driving clock, which he had himself invented. gradually the establishment at greenwich waxed great under his incessant care. it was the custom for the observatory to be inspected every year by a board of visitors, whose chairman was the president of the royal society. at each annual visitation, held on the first saturday in june, the visitors received a report from the astronomer royal, in which he set forth the business which had been accomplished during the past year. it was on these occasions that applications were made to the admiralty, either for new instruments or for developing the work of the observatory in some other way. after the more official business of the inspection was over, the observatory was thrown open to visitors, and hundreds of people enjoyed on that day the privilege of seeing the national observatory. these annual gatherings are happily still continued, and the first saturday in june is known to be the occasion of one of the most interesting reunions of scientific men which takes place in the course of the year. airy's scientific work was, however, by no means confined to the observatory. he interested himself largely in expeditions for the observation of eclipses and in projects for the measurement of arcs on the earth. he devoted much attention to the collection of magnetic observations from various parts of the world. especially will it be remembered that the circumstances of the transits of venus, which occurred in 1874 and in 1882, were investigated by him, and under his guidance expeditions were sent forth to observe the transits from those localities in remote parts of the earth where observations most suitable for the determination of the sun's distance from the earth could be obtained. the astronomer royal also studied tidal phenomena, and he rendered great service to the country in the restoration of the standards of length and weight which had been destroyed in the great fire at the house of parliament in october, 1834. in the most practical scientific matters his advice was often sought, and was as cheerfully rendered. now we find him engaged in an investigation of the irregularities of the compass in iron ships, with a view to remedying its defects; now we find him reporting on the best gauge for railways. among the most generally useful developments of the observatory must be mentioned the telegraphic method for the distribution of exact time. by arrangement with the post office, the astronomers at greenwich despatch each morning a signal from the observatory to london at ten o'clock precisely. by special apparatus, this signal is thence distributed automatically over the country, so as to enable the time to be known everywhere accurately to a single second. it was part of the same system that a time ball should be dropped daily at one o'clock at deal, as well as at other places, for the purpose of enabling ship's chronometers to be regulated. airy's writings were most voluminous, and no fewer than forty-eight memoirs by him are mentioned in the "catalogue of scientific memoirs," published by the royal society up to the year 1873, and this only included ten years out of an entire life of most extraordinary activity. many other subjects besides those of a purely scientific character from time to time engaged his attention. he wrote, for instance, a very interesting treatise on the roman invasion of britain, especially with a view of determining the port from which caesar set forth from gaul, and the point at which he landed on the british coast. airy was doubtless led to this investigation by his study of the tidal phenomena in the straits of dover. perhaps the astronomer royal is best known to the general reading public by his excellent lectures on astronomy, delivered at the ipswich museum in 1848. this book has passed through many editions, and it gives a most admirable account of the manner in which the fundamental problems in astronomy have to be attacked. as years rolled by almost every honour and distinction that could be conferred upon a scientific man was awarded to sir george airy. he was, indeed, the recipient of other honours not often awarded for scientific distinction. among these we may mention that in 1875 he received the freedom of the city of london, "as a recognition of his indefatigable labours in astronomy, and of his eminent services in the advancement of practical science, whereby he has so materially benefited the cause of commerce and civilisation." until his eightieth year airy continued to discharge his labours at greenwich with unflagging energy. at last, on august 15th, 1881, he resigned the office which he had held so long with such distinction to himself and such benefit to his country. he had married in 1830 the daughter of the rev. richard smith, of edensor. lady airy died in 1875, and three sons and three daughters survived him. one daughter is the wife of dr. routh, of cambridge, and his other daughters were the constant companions of their father during the declining years of his life. up to the age of ninety he enjoyed perfect physical health, but an accidental fall which then occurred was attended with serious results. he died on saturday, january 2nd, 1892, and was buried in the churchyard at playford. hamilton. william rowan hamilton was born at midnight between the 3rd and 4th of august, 1805, at dublin, in the house which was then 29, but subsequently 36, dominick street. his father, archibald hamilton, was a solicitor, and william was the fourth of a family of nine. with reference to his descent, it may be sufficient to notice that his ancestors appear to have been chiefly of gentle irish families, but that his maternal grandmother was of scottish birth. when he was about a year old, his father and mother decided to hand over the education of the child to his uncle, james hamilton, a clergyman of trim, in county meath. james hamilton's sister, sydney, resided with him, and it was in their home that the days of william's childhood were passed. in mr. graves' "life of sir william rowan hamilton" a series of letters will be found, in which aunt sydney details the progress of the boy to his mother in dublin. probably there is no record of an infant prodigy more extraordinary than that which these letters contain. at three years old his aunt assured the mother that william is "a hopeful blade," but at that time it was his physical vigour to which she apparently referred; for the proofs of his capacity, which she adduces, related to his prowess in making boys older than himself fly before him. in the second letter, a month later, we hear that william is brought in to read the bible for the purpose of putting to shame other boys double his age who could not read nearly so well. uncle james appears to have taken much pains with william's schooling, but his aunt said that "how he picks up everything is astonishing, for he never stops playing and jumping about." when he was four years and three months old, we hear that he went out to dine at the vicar's, and amused the company by reading for them equally well whether the book was turned upside down or held in any other fashion. his aunt assures the mother that "willie is a most sensible little creature, but at the same time has a great deal of roguery." at four years and five months old he came up to pay his mother a visit in town, and she writes to her sister a description of the boy;-"his reciting is astonishing, and his clear and accurate knowledge of geography is beyond belief; he even draws the countries with a pencil on paper, and will cut them out, though not perfectly accurate, yet so well that a anybody knowing the countries could not mistake them; but, you will think this nothing when i tell you that he reads latin, greek, and hebrew." aunt sydney recorded that the moment willie got back to trim he was desirous of at once resuming his former pursuits. he would not eat his breakfast till his uncle had heard him his hebrew, and he comments on the importance of proper pronunciation. at five he was taken to see a friend, to whom he repeated long passages from dryden. a gentleman present, who was not unnaturally sceptical about willie's attainments, desired to test him in greek, and took down a copy of homer which happened to have the contracted type, and to his amazement willie went on with the greatest ease. at six years and nine months he was translating homer and virgil; a year later his uncle tells us that william finds so little difficulty in learning french and italian, that he wishes to read homer in french. he is enraptured with the iliad, and carries it about with him, repeating from it whatever particularly pleases him. at eight years and one month the boy was one of a party who visited the scalp in the dublin mountains, and he was so delighted with the scenery that he forthwith delivered an oration in latin. at nine years and six months he is not satisfied until he learns sanscrit; three months later his thirst for the oriental languages is unabated, and at ten years and four months he is studying arabic and persian. when nearly twelve he prepared a manuscript ready for publication. it was a "syriac grammar," in syriac letters and characters compiled from that of buxtorf, by william hamilton, esq., of dublin and trim. when he was fourteen, the persian ambassador, mirza abul hassan khan, paid a visit to dublin, and, as a practical exercise in his oriental languages, the young scholar addressed to his excellency a letter in persian; a translation of which production is given by mr. graves. when william was fourteen he had the misfortune to lose his father; and he had lost his mother two years previously. the boy and his three sisters were kindly provided for by different members of the family on both sides. it was when william was about fifteen that his attention began to be turned towards scientific subjects. these were at first regarded rather as a relaxation from the linguistic studies with which he had been so largely occupied. on november 22nd, 1820, he notes in his journal that he had begun newton's "principia": he commenced also the study of astronomy by observing eclipses, occultations, and similar phenomena. when he was sixteen we learn that he had read conic sections, and that he was engaged in the study of pendulums. after an attack of illness, he was moved for change to dublin, and in may, 1822, we find him reading the differential calculus and laplace's "mecanique celeste." he criticises an important part of laplace's work relative to the demonstration of the parallelogram of forces. in this same year appeared the first gushes of those poems which afterwards flowed in torrents. his somewhat discursive studies had, however, now to give place to a more definite course of reading in preparation for entrance to the university of dublin. the tutor under whom he entered, charles boyton, was himself a distinguished man, but he frankly told the young william that he could be of little use to him as a tutor, for his pupil was quite as fit to be his tutor. eliza hamilton, by whom this is recorded, adds, "but there is one thing which boyton would promise to be to him, and that was a friend; and that one proof he would give of this should be that, if ever he saw william beginning to be upset by the sensation he would excite, and the notice he would attract, he would tell him of it." at the beginning of his college career he distanced all his competitors in every intellectual pursuit. at his first term examination in the university he was first in classics and first in mathematics, while he received the chancellor's prize for a poem on the ionian islands, and another for his poem on eustace de st. pierre. there is abundant testimony that hamilton had "a heart for friendship formed." among the warmest of the friends whom he made in these early days was the gifted maria edgeworth, who writes to her sister about "young mr. hamilton, an admirable crichton of eighteen, a real prodigy of talents, who dr. brinkley says may be a second newton, quiet, gentle, and simple." his sister eliza, to whom he was affectionately attached, writes to him in 1824:-"i had been drawing pictures of you in my mind in your study at cumberland street with 'xenophon,' &c., on the table, and you, with your most awfully sublime face of thought, now sitting down, and now walking about, at times rubbing your hands with an air of satisfaction, and at times bursting forth into some very heroical strain of poetry in an unknown language, and in your own internal solemn ventriloquist-like voice, when you address yourself to the silence and solitude of your own room, and indeed, at times, even when your mysterious poetical addresses are not quite unheard." this letter is quoted because it refers to a circumstance which all who ever met with hamilton, even in his latest years, will remember. he was endowed with two distinct voices, one a high treble, the other a deep bass, and he alternately employed these voices not only in ordinary conversation, but when he was delivering an address on the profundities of quaternions to the royal irish academy, or on similar occasions. his friends had long grown so familiar with this peculiarity that they were sometimes rather surprised to find how ludicrous it appeared to strangers. hamilton was fortunate in finding, while still at a very early age, a career open before him which was worthy of his talents. he had not ceased to be an undergraduate before he was called to fill an illustrious chair in his university. the circumstances are briefly as follows. we have already mentioned that, in 1826, brinkley was appointed bishop of cloyne, and the professorship of astronomy thereupon became vacant. such was hamilton's conspicuous eminence that, notwithstanding he was still an undergraduate, and had only just completed his twenty-first year, he was immediately thought of as a suitable successor to the chair. indeed, so remarkable were his talents in almost every direction that had the vacancy been in the professorship of classics or of mathematics, of english literature or of metaphysics, of modern or of oriental languages, it seems difficult to suppose that he would not have occurred to every one as a possible successor. the chief ground, however, on which the friends of hamilton urged his appointment was the earnest of original power which he had already shown in a research on the theory of systems of rays. this profound work created a new branch of optics, and led a few years later to a superb discovery, by which the fame of its author became world-wide. at first hamilton thought it would be presumption for him to apply for so exalted a position; he accordingly retired to the country, and resumed his studies for his degree. other eminent candidates came forward, among them some from cambridge, and a few of the fellows from trinity college, dublin, also sent in their claims. it was not until hamilton received an urgent letter from his tutor boyton, in which he was assured of the favourable disposition of the board towards his candidature, that he consented to come forward, and on june 16th, 1827, he was unanimously chosen to succeed the bishop of cloyne as professor of astronomy in the university. the appointment met with almost universal approval. it should, however, be noted that brinkley, whom hamilton succeeded, did not concur in the general sentiment. no one could have formed a higher opinion than he had done of hamilton's transcendent powers; indeed, it was on that very ground that he seemed to view the appointment with disapprobation. he considered that it would have been wiser for hamilton to have obtained a fellowship, in which capacity he would have been able to exercise a greater freedom in his choice of intellectual pursuits. the bishop seems to have thought, and not without reason, that hamilton's genius would rather recoil from much of the routine work of an astronomical establishment. now that hamilton's whole life is before us, it is easy to see that the bishop was entirely wrong. it is quite true that hamilton never became a skilled astronomical observer; but the seclusion of the observatory was eminently favourable to those gigantic labours to which his life was devoted, and which have shed so much lustre, not only on hamilton himself, but also on his university and his country. in his early years at dunsink, hamilton did make some attempts at a practical use of the telescopes, but he possessed no natural aptitude for such work, while exposure which it involved seems to have acted injuriously on his health. he, therefore, gradually allowed his attention to be devoted to those mathematical researches in which he had already given such promise of distinction. although it was in pure mathematics that he ultimately won his greatest fame, yet he always maintained and maintained with justice, that he had ample claims to the title of an astronomer. in his later years he set forth this position himself in a rather striking manner. de morgan had written commending to hamilton's notice grant's "history of physical astronomy." after becoming acquainted with the book, hamilton writes to his friend as follows:-"the book is very valuable, and very creditable to its composer. but your humble servant may be pardoned if he finds himself somewhat amused at the title, 'history of physical astronomy from the earliest ages to the middle of the nineteenth century,' when he fails to observe any notice of the discoveries of sir w. r. hamilton in the theory of the 'dynamics of the heavens.'" the intimacy between the two correspondents will account for the tone of this letter; and, indeed, hamilton supplies in the lines which follow ample grounds for his complaint. he tells how jacobi spoke of him in manchester in 1842 as "le lagrange de votre pays," and how donkin had said that, "the analytical theory of dynamics as it exists at present is due mainly to the labours of la grange poisson, sir w. r. hamilton, and jacobi, whose researches on this subject present a series of discoveries hardly paralleled for their elegance and importance in any other branch of mathematics." in the same letter hamilton also alludes to the success which had attended the applications of his methods in other hands than his own to the elucidation of the difficult subject of planetary perturbations. even had his contributions to science amounted to no more than these discoveries, his tenure of the chair would have been an illustrious one. it happens, however, that in the gigantic mass of his intellectual work these researches, though intrinsically of such importance, assume what might almost be described as a relative insignificance. the most famous achievement of hamilton's earlier years at the observatory was the discovery of conical refraction. this was one of those rare events in the history of science, in which a sagacious calculation has predicted a result of an almost startling character, subsequently confirmed by observation. at once this conferred on the young professor a world-wide renown. indeed, though he was still only twenty-seven, he had already lived through an amount of intellectual activity which would have been remarkable for a man of threescore and ten. simultaneously with his growth in fame came the growth of his several friendships. there were, in the first place, his scientific friendships with herschel, robinson, and many others with whom he had copious correspondence. in the excellent biography to which i have referred, hamilton's correspondence with coleridge may be read, as can also the letters to his lady correspondents, among them being maria edgeworth, lady dunraven, and lady campbell. many of these sheets relate to literary matters, but they are largely intermingled with genial pleasantry, and serve at all events to show the affection and esteem with which he was regarded by all who had the privilege of knowing him. there are also the letters to the sisters whom he adored, letters brimming over with such exalted sentiment, that most ordinary sisters would be tempted to receive them with a smile in the excessively improbable event of their still more ordinary brothers attempting to pen such effusions. there are also indications of letters to and from other young ladies who from time to time were the objects of hamilton's tender admiration. we use the plural advisedly, for, as mr. graves has set forth, hamilton's love affairs pursued a rather troubled course. the attention which he lavished on one or two fair ones was not reciprocated, and even the intense charms of mathematical discovery could not assuage the pangs which the disappointed lover experienced. at last he reached the haven of matrimony in 1833, when he was married to miss bayly. of his married life hamilton said, many years later to de morgan, that it was as happy as he expected, and happier than he deserved. he had two sons, william and archibald, and one daughter, helen, who became the wife of archdeacon o'regan. [plate: sir w. rowan hamilton.] the most remarkable of hamilton's friendships in his early years was unquestionably that with wordsworth. it commenced with hamilton's visit to keswick; and on the first evening, when the poet met the young mathematician, an incident occurred which showed the mutual interest that was aroused. hamilton thus describes it in a letter to his sister eliza:-"he (wordsworth) walked back with our party as far as their lodge, and then, on our bidding mrs. harrison good-night, i offered to walk back with him while my party proceeded to the hotel. this offer he accepted, and our conversation had become so interesting that when we had arrived at his home, a distance of about a mile, he proposed to walk back with me on my way to ambleside, a proposal which you may be sure i did not reject; so far from it that when he came to turn once more towards his home i also turned once more along with him. it was very late when i reached the hotel after all this walking." hamilton also submitted to wordsworth an original poem, entitled "it haunts me yet." the reply of wordsworth is worth repeating:-"with a safe conscience i can assure you that, in my judgment, your verses are animated with the poetic spirit, as they are evidently the product of strong feeling. the sixth and seventh stanzas affected me much, even to the dimming of my eyes and faltering of my voice while i was reading them aloud. having said this, i have said enough. now for the per contra. you will not, i am sure, be hurt when i tell you that the workmanship (what else could be expected from so young a writer?) is not what it ought to be. . . "my household desire to be remembered to you in no formal way. seldom have i parted--never, i was going to say--with one whom after so short an acquaintance i lost sight of with more regret. i trust we shall meet again." the further affectionate intercourse between hamilton and wordsworth is fully set forth, and to hamilton's latest years a recollection of his "rydal hours" was carefully treasured and frequently referred to. wordsworth visited hamilton at the observatory, where a beautiful shady path in the garden is to the present day spoken of as "wordsworth's walk." it was the practice of hamilton to produce a sonnet on almost every occasion which admitted of poetical treatment, and it was his delight to communicate his verses to his friends all round. when whewell was producing his "bridgewater treatises," he writes to hamilton in 1833:-"your sonnet which you showed me expressed much better than i could express it the feeling with which i tried to write this book, and i once intended to ask your permission to prefix the sonnet to my book, but my friends persuaded me that i ought to tell my story in my own prose, however much better your verse might be." the first epoch-marking contribution to theoretical dynamics after the time of newton was undoubtedly made by lagrange, in his discovery of the general equations of motion. the next great step in the same direction was that taken by hamilton in his discovery of a still more comprehensive method. of this contribution hamilton writes to whewell, march 31st, 1834:-"as to my late paper, a day or two ago sent off to london, it is merely mathematical and deductive. i ventured, indeed, to call it the 'mecanique analytique' of lagrange, 'a scientific poem'; and spoke of dynamics, or the science of force, as treating of 'power acting by law in space and time.' in other respects it is as unpoetical and unmetaphysical as my gravest friends could desire." it may well be doubted whether there is a more beautiful chapter in the whole of mathematical philosophy than that which contains hamilton's dynamical theory. it is disfigured by no tedious complexity of symbols; it condescends not to any particular problems; it is an all embracing theory, which gives an intellectual grasp of the most appropriate method for discovering the result of the application of force to matter. it is the very generality of this doctrine which has somewhat impeded the applications of which it is susceptible. the exigencies of examinations are partly responsible for the fact that the method has not become more familiar to students of the higher mathematics. an eminent professor has complained that hamilton's essay on dynamics was of such an extremely abstract character, that he found himself unable to extract from it problems suitable for his examination papers. the following extract is from a letter of professor sylvester to hamilton, dated 20th of september, 1841. it will show how his works were appreciated by so consummate a mathematician as the writer:-"believe me, sir, it is not the least of my regrets in quitting this empire to feel that i forego the casual occasion of meeting those masters of my art, yourself chief amongst the number, whose acquaintance, whose conversation, or even notice, have in themselves the power to inspire, and almost to impart fresh vigour to the understanding, and the courage and faith without which the efforts of invention are in vain. the golden moments i enjoyed under your hospitable roof at dunsink, or moments such as they were, may probably never again fall to my lot. "at a vast distance, and in an humble eminence, i still promise myself the calm satisfaction of observing your blazing course in the elevated regions of discovery. such national honour as you are able to confer on your country is, perhaps, the only species of that luxury for the rich (i mean what is termed one's glory) which is not bought at the expense of the comforts of the million." the study of metaphysics was always a favourite recreation when hamilton sought for a change from the pursuit of mathematics. in the year 1834 we find him a diligent student of kant; and, to show the views of the author of quaternions and of algebra as the science of pure time on the "critique of the pure reason," we quote the following letter, dated 18th of july, 1834, from hamilton to viscount adare:-"i have read a large part of the 'critique of the pure reason,' and find it wonderfully clear, and generally quite convincing. notwithstanding some previous preparation from berkeley, and from my own thoughts, i seem to have learned much from kant's own statement of his views of 'space and time.' yet, on the whole, a large part of my pleasure consists in recognising through kant's works, opinions, or rather views, which have been long familiar to myself, although far more clearly and systematically expressed and combined by him. . . . kant is, i think, much more indebted than he owns, or, perhaps knows, to berkeley, whom he calls by a sneer, 'gutem berkeley'. . . as it were, 'good soul, well meaning man,' who was able for all that to shake to its centre the world of human thought, and to effect a revolution among the early consequences of which was the growth of kant himself." at several meetings of the british association hamilton was a very conspicuous figure. especially was this the case in 1835, when the association met in dublin, and when hamilton, though then but thirty years old, had attained such celebrity that even among a very brilliant gathering his name was perhaps the most renowned. a banquet was given at trinity college in honour of the meeting. the distinguished visitors assembled in the library of the university. the earl of mulgrave, then lord lieutenant of ireland, made this the opportunity of conferring on hamilton the honour of knighthood, gracefully adding, as he did so: "i but set the royal, and therefore the national mark, on a distinction already acquired by your genius and labours." the banquet followed, writes mr. graves. "it was no little addition to the honour hamilton had already received that, when professor whewell returned thanks for the toast of the university of cambridge, he thought it appropriate to add the words, 'there was one point which strongly pressed upon him at that moment: it was now one hundred and thirty years since a great man in another trinity college knelt down before his sovereign, and rose up sir isaac newton.' the compliment was welcomed by immense applause." a more substantial recognition of the labours of hamilton took place subsequently. he thus describes it in a letter to mr. graves of 14th of november, 1843:-"the queen has been pleased--and you will not doubt that it was entirely unsolicited, and even unexpected, on my part--'to express her entire approbation of the grant of a pension of two hundred pounds per annum from the civil list' to me for scientific services. the letters from sir robert peel and from the lord lieutenant of ireland in which this grant has been communicated or referred to have been really more gratifying to my feelings than the addition to my income, however useful, and almost necessary, that may have been." the circumstances we have mentioned might lead to the supposition that hamilton was then at the zenith of his fame but this was not so. it might more truly be said, that his achievements up to this point were rather the preliminary exercises which fitted him for the gigantic task of his life. the name of hamilton is now chiefly associated with his memorable invention of the calculus of quaternions. it was to the creation of this branch of mathematics that the maturer powers of his life were devoted; in fact he gives us himself an illustration of how completely habituated he became to the new modes of thought which quaternions originated. in one of his later years he happened to take up a copy of his famous paper on dynamics, a paper which at the time created such a sensation among mathematicians, and which is at this moment regarded as one of the classics of dynamical literature. he read, he tells us, his paper with considerable interest, and expressed his feelings of gratification that he found himself still able to follow its reasoning without undue effort. but it seemed to him all the time as a work belonging to an age of analysis now entirely superseded. in order to realise the magnitude of the revolution which hamilton has wrought in the application of symbols to mathematical investigation, it is necessary to think of what hamilton did beside the mighty advance made by descartes. to describe the character of the quaternion calculus would be unsuited to the pages of this work, but we may quote an interesting letter, written by hamilton from his death-bed, twenty-two years later, to his son archibald, in which he has recorded the circumstances of the discovery:-"indeed, i happen to be able to put the finger of memory upon the year and month--october, 1843--when having recently returned from visits to cork and parsonstown, connected with a meeting of the british association, the desire to discover the laws of multiplication referred to, regained with me a certain strength and earnestness which had for years been dormant, but was then on the point of being gratified, and was occasionally talked of with you. every morning in the early part of the above-cited month, on my coming down to breakfast, your (then) little brother william edwin, and yourself, used to ask me, 'well papa, can you multiply triplets?' whereto i was always obliged to reply, with a sad shake of the head: 'no, i can only add and subtract them,' "but on the 16th day of the same month--which happened to be monday, and a council day of the royal irish academy--i was walking in to attend and preside, and your mother was walking with me along the royal canal, to which she had perhaps driven; and although she talked with me now and then, yet an undercurrent of thought was going on in my mind which gave at last a result, whereof it is not too much to say that i felt at once the importance. an electric circuit seemed to close; and a spark flashed forth the herald (as i foresaw immediately) of many long years to come of definitely directed thought and work by myself, if spared, and, at all events, on the part of others if i should even be allowed to live long enough distinctly to communicate the discovery. nor could i resist the impulse--unphilosophical as it may have been--to cut with a knife on a stone of brougham bridge as we passed it, the fundamental formula which contains the solution of the problem, but, of course, the inscription has long since mouldered away. a more durable notice remains, however, on the council books of the academy for that day (october 16, 1843), which records the fact that i then asked for and obtained leave to read a paper on 'quaternions,' at the first general meeting of the session; which reading took place accordingly, on monday, the 13th of november following." writing to professor tait, hamilton gives further particulars of the same event. and again in a letter to the rev. j. w. stubbs:-"to-morrow will be the fifteenth birthday of the quaternions. they started into life full-grown on the 16th october, 1843, as i was walking with lady hamilton to dublin, and came up to brougham bridge--which my boys have since called quaternion bridge. i pulled out a pocketbook which still exists, and made entry, on which at the very moment i felt that it might be worth my while to expend the labour of at least ten or fifteen years to come. but then it is fair to say that this was because i felt a problem to have been at that moment solved, an intellectual want relieved which had haunted me for at least fifteen years before. "but did the thought of establishing such a system, in which geometrically opposite facts--namely, two lines (or areas) which are opposite in space give always a positive product--ever come into anybody's head till i was led to it in october, 1843, by trying to extend my old theory of algebraic couples, and of algebra as the science of pure time? as to my regarding geometrical addition of lines as equivalent to composition of motions (and as performed by the same rules), that is indeed essential in my theory but not peculiar to it; on the contrary, i am only one of many who have been led to this view of addition." pilgrims in future ages will doubtless visit the spot commemorated by the invention of quaternions. perhaps as they look at that by no means graceful structure quaternion bridge, they will regret that the hand of some old mortality had not been occasionally employed in cutting the memorable inscription afresh. it is now irrecoverably lost. it was ten years after the discovery that the great volume appeared under the title of "lectures on quaternions," dublin, 1853. the reception of this work by the scientific world was such as might have been expected from the extraordinary reputation of its author, and the novelty and importance of the new calculus. his valued friend, sir john herschel, writes to him in that style of which he was a master:-"now, most heartily let me congratulate you on getting out your book--on having found utterance, ore rotundo, for all that labouring and seething mass of thought which has been from time to time sending out sparks, and gleams, and smokes, and shaking the soil about you; but now breaks into a good honest eruption, with a lava stream and a shower of fertilizing ashes. "metaphor and simile apart, there is work for a twelve-month to any man to read such a book, and for half a lifetime to digest it, and i am glad to see it brought to a conclusion." we may also record hamilton's own opinion expressed to humphrey lloyd:-"in general, although in one sense i hope that i am actually growing modest about the quaternions, from my seeing so many peeps and vistas into future expansions of their principles, i still must assert that this discovery appears to me to be as important for the middle of the nineteenth century as the discovery of fluxions was for the close of the seventeenth." bartholomew lloyd died in 1837. he had been the provost of trinity college, and the president of the royal irish academy. three candidates were put forward by their respective friends for the vacant presidency. one was humphrey lloyd, the son of the late provost, and the two others were hamilton and archbishop whately. lloyd from the first urged strongly the claims of hamilton, and deprecated the putting forward of his own name. hamilton in like manner desired to withdraw in favour of lloyd. the wish was strongly felt by many of the fellows of the college that lloyd should be elected, in consequence of his having a more intimate association with collegiate life than hamilton; while his scientific eminence was world-wide. the election ultimately gave hamilton a considerable majority over lloyd, behind whom the archbishop followed at a considerable distance. all concluded happily, for both lloyd and the archbishop expressed, and no doubt felt, the pre-eminent claims of hamilton, and both of them cordially accepted the office of a vice-president, to which, according to the constitution of the academy, it is the privilege of the incoming president to nominate. in another chapter i have mentioned as a memorable episode in astronomical history, that sir j. herschel went for a prolonged sojourn to the cape of good hope, for the purpose of submitting the southern skies to the same scrutiny with the great telescope that his father had given to the northern skies. the occasion of herschel's return after the brilliant success of his enterprise, was celebrated by a banquet. on june 15th, 1838, hamilton was assigned the high honour of proposing the health of herschel. this banquet is otherwise memorable in hamilton's career as being one of the two occasions in which he was in the company of his intimate friend de morgan. in the year 1838 a scheme was adopted by the royal irish academy for the award of medals to the authors of papers which appeared to possess exceptionally high merit. at the institution of the medal two papers were named in competition for the prize. one was hamilton's "memoir on algebra, as the science of pure time." the other was macullagh's paper on the "laws of crystalline reflection and refraction." hamilton expresses his gratification that, mainly in consequence of his own exertions, he succeeded in having the medal awarded to macullagh rather than to himself. indeed, it would almost appear as if hamilton had procured a letter from sir j. herschel, which indicated the importance of macullagh's memoir in such a way as to decide the issue. it then became hamilton's duty to award the medal from the chair, and to deliver an address in which he expressed his own sense of the excellence of macullagh's scientific work. it is the more necessary to allude to these points, because in the whole of his scientific career it would seem that macullagh was the only man with whom hamilton had ever even an approach to a dispute about priority. the incident referred to took place in connection with the discovery of conical refraction, the fame of which macullagh made a preposterous attempt to wrest from hamilton. this is evidently alluded to in hamilton's letter to the marquis of northampton, dated june 28th, 1838, in which we read:-"and though some former circumstances prevented me from applying to the person thus distinguished the sacred name of friend, i had the pleasure of doing justice...to his high intellectual merits... i believe he was not only gratified but touched, and may, perhaps, regard me in future with feelings more like those which i long to entertain towards him." hamilton was in the habit, from time to time, of commencing the keeping of a journal, but it does not appear to have been systematically conducted. whatever difficulties the biographer may have experienced from its imperfections and irregularities, seem to be amply compensated for by the practice which hamilton had of preserving copies of his letters, and even of comparatively insignificant memoranda. in fact, the minuteness with which apparently trivial matters were often noted down appears almost whimsical. he frequently made a memorandum of the name of the person who carried a letter to the post, and of the hour in which it was despatched. on the other hand, the letters which he received were also carefully preserved in a mighty mass of manuscripts, with which his study was encumbered, and with which many other parts of the house were not unfrequently invaded. if a letter was laid aside for a few hours, it would become lost to view amid the seething mass of papers, though occasionally, to use his own expression, it might be seen "eddying" to the surface in some later disturbance. the great volume of "lectures on quaternions" had been issued, and the author had received the honours which the completion of such a task would rightfully bring him. the publication of an immortal work does not, however, necessarily provide the means for paying the printer's bill. the printing of so robust a volume was necessarily costly; and even if all the copies could be sold, which at the time did not seem very likely, they would hardly have met the inevitable expenses. the provision of the necessary funds was, therefore, a matter for consideration. the board of trinity college had already contributed 200 pounds to the printing, but yet another hundred was required. even the discoverer of quaternions found this a source of much anxiety. however, the board, urged by the representation of humphrey lloyd, now one of its members, and, as we have already seen, one of hamilton's staunchest friends, relieved him of all liability. we may here note that, notwithstanding the pension which hamilton enjoyed in addition to the salary of his chair, he seems always to have been in some what straitened circumstances, or, to use his own words in one of his letters to de morgan, "though not an embarrassed man, i am anything rather than a rich one." it appears that, notwithstanding the world-wide fame of hamilton's discoveries, the only profit in a pecuniary sense that he ever obtained from any of his works was by the sale of what he called his icosian game. some enterprising publisher, on the urgent representations of one of hamilton's friends in london, bought the copyright of the icosian game for 25 pounds. even this little speculation proved unfortunate for the purchaser, as the public could not be induced to take the necessary interest in the matter. after the completion of his great book, hamilton appeared for awhile to permit himself a greater indulgence than usual in literary relaxations. he had copious correspondence with his intimate friend, aubrey de vere, and there were multitudes of letters from those troops of friends whom it was hamilton's privilege to possess. he had been greatly affected by the death of his beloved sister eliza, a poetess of much taste and feeling. she left to him her many papers to preserve or to destroy, but he said it was only after the expiration of four years of mourning that he took courage to open her pet box of letters. the religious side of hamilton's character is frequently illustrated in these letters; especially is this brought out in the correspondence with de vere, who had seceded to the church of rome. hamilton writes, august 4, 1855:-"if, then, it be painfully evident to both, that under such circumstances there cannot (whatever we may both desire) be now in the nature of things, or of minds, the same degree of intimacy between us as of old; since we could no longer talk with the same degree of unreserve on every subject which happened to present itself, but must, from the simplest instincts of courtesy, be each on his guard not to say what might be offensive, or, at least, painful to the other; yet we were once so intimate, and retain still, and, as i trust, shall always retain, so much of regard and esteem and appreciation for each other, made tender by so many associations of my early youth and your boyhood, which can never be forgotten by either of us, that (as times go) two or three very respectable friendships might easily be carved out from the fragments of our former and ever-to-be-remembered intimacy. it would be no exaggeration to quote the words: 'heu! quanto minus est cum reliquis versari, quam tui meminisse!'" in 1858 a correspondence on the subject of quaternions commenced between professor tait and sir william hamilton. it was particularly gratifying to the discoverer that so competent a mathematician as professor tait should have made himself acquainted with the new calculus. it is, of course, well known that professor tait subsequently brought out a most valuable elementary treatise on quaternions, to which those who are anxious to become acquainted with the subject will often turn in preference to the tremendous work of hamilton. in the year 1861 gratifying information came to hand of the progress which the study of quaternions was making abroad. especially did the subject attract the attention of that accomplished mathematician, moebius, who had already in his "barycentrische calculus" been led to conceptions which bore more affinity to quaternions than could be found in the writings of any other mathematician. such notices of his work were always pleasing to hamilton, and they served, perhaps, as incentives to that still closer and more engrossing labour by which he became more and more absorbed. during the last few years of his life he was observed to be even more of a recluse than he had hitherto been. his powers of long and continuous study seemed to grow with advancing years, and his intervals of relaxation, such as they were, became more brief and more infrequent. it was not unusual for him to work for twelve hours at a stretch. the dawn would frequently surprise him as he looked up to snuff his candles after a night of fascinating labour at original research. regularity in habits was impossible to a student who had prolonged fits of what he called his mathematical trances. hours for rest and hours for meals could only be snatched in the occasional the lucid intervals between one attack of quaternions and the next. when hungry, he would go to see whether anything could be found on the sideboard; when thirsty, he would visit the locker, and the one blemish in the man's personal character is that these latter visits were sometimes paid too often. as an example of one of hamilton's rare diversions from the allabsorbing pursuit of quaternions, we find that he was seized with curiosity to calculate back to the date of the hegira, which he found on the 15th july, 622. he speaks of the satisfaction with which he ascertained subsequently that herschel had assigned precisely the same date. metaphysics remained also, as it had ever been, a favourite subject of hamilton's readings and meditations and of correspondence with his friends. he wrote a very long letter to dr. ingleby on the subject of his "introduction to metaphysics." in it hamilton alludes, as he has done also in other places, to a peculiarity of his own vision. it was habitual to him, by some defect in the correlation of his eyes, to see always a distinct image with each; in fact, he speaks of the remarkable effect which the use of a good stereoscope had on his sensations of vision. it was then, for the first time, that he realised how the two images which he had always seen hitherto would, under normal circumstances, be blended into one. he cites this fact as bearing on the phenomena of binocular vision, and he draws from it the inference that the necessity of binocular vision for the correct appreciation of distance is unfounded. "i am quite sure," he says, "that i see distance with each eye separately." the commencement of 1865, the last year of his life saw hamilton as diligent as ever, and corresponding with salmon and cayley. on april 26th he writes to a friend to say, that his health has not been good for years past, and that so much work has injured his constitution; and he adds, that it is not conducive to good spirits to find that he is accumulating another heavy bill with the printer for the publication of the "elements." this was, indeed, up to the day of his death, a cause for serious anxiety. it may, however, be mentioned that the whole cost, which amounted to nearly 500 pounds, was, like that of the previous volume, ultimately borne by the college. contrary to anticipation, the enterprise, even in a pecuniary sense, cannot have been a very unprofitable one. the whole edition has long been out of print, and as much as 5 pounds has since been paid for a single copy. it was on the 9th of may, 1865, that hamilton was in dublin for the last time. a few days later he had a violent attack of gout, and on the 4th of june he became alarmingly ill, and on the next day had an attack of epileptic convulsions. however, he slightly rallied, so that before the end of the month he was again at work at the "elements." a gratifying incident brightened some of the last days of his life. the national academy of science in america had then been just formed. a list of foreign associates had to be chosen from the whole world, and a discussion took place as to what name should be placed first on the list. hamilton was informed by private communication that this great distinction was awarded to him by a majority of two-thirds. in august he was still at work on the table of contents of the "elements," and one of his very latest efforts was his letter to mr. gould, in america, communicating his acknowledgements of the honour which had been just conferred upon him by the national academy. on the 2nd of september mr. graves went to the observatory, in response to a summons, and the great mathematician at once admitted to his friend that he felt the end was approaching. he mentioned that he had found in the 145th psalm a wonderfully suitable expression of his thoughts and feelings, and he wished to testify his faith and thankfulness as a christian by partaking of the lord's supper. he died at half-past two on the afternoon of the 2nd of september, 1865, aged sixty years and one month. he was buried in mount jerome cemetery on the 7th of september. many were the letters and other more public manifestations of the feelings awakened by hamilton's death. sir john herschel wrote to the widow:-"permit me only to add that among the many scientific friends whom time has deprived me of, there has been none whom i more deeply lament, not only for his splendid talents, but for the excellence of his disposition and the perfect simplicity of his manners--so great, and yet devoid of pretensions." de morgan, his old mathematical crony, as hamilton affectionately styled him, also wrote to lady hamilton:-"i have called him one of my dearest friends, and most truly; for i know not how much longer than twenty-five years we have been in intimate correspondence, of most friendly agreement or disagreement, of most cordial interest in each other. and yet we did not know each other's faces. i met him about 1830 at babbage's breakfast table, and there for the only time in our lives we conversed. i saw him, a long way off, at the dinner given to herschel (about 1838) on his return from the cape and there we were not near enough, nor on that crowded day could we get near enough, to exchange a word. and this is all i ever saw, and, so it has pleased god, all i shall see in this world of a man whose friendly communications were among my greatest social enjoyments, and greatest intellectual treats." there is a very interesting memoir of hamilton written by de morgan, in the "gentleman's magazine" for 1866, in which he produces an excellent sketch of his friend, illustrated by personal reminiscences and anecdotes. he alludes, among other things, to the picturesque confusion of the papers in his study. there was some sort of order in the mass, discernible however, by hamilton alone, and any invasion of the domestics, with a view to tidying up, would throw the mathematician as we are informed, into "a good honest thundering passion." hardly any two men, who were both powerful mathematicians, could have been more dissimilar in every other respect than were hamilton and de morgan. the highly poetical temperament of hamilton was remarkably contrasted with the practical realism of de morgan. hamilton sends sonnets to his friend, who replies by giving the poet advice about making his will. the metaphysical subtleties, with which hamilton often filled his sheets, did not seem to have the same attraction for de morgan that he found in battles about the quantification of the predicate. de morgan was exquisitely witty, and though his jokes were always appreciated by his correspondent, yet hamilton seldom ventured on anything of the same kind in reply; indeed his rare attempts at humour only produced results of the most ponderous description. but never were two scientific correspondents more perfectly in sympathy with each other. hamilton's work on quaternions, his labours in dynamics, his literary tastes, his metaphysics, and his poetry, were all heartily welcomed by his friend, whose letters in reply invariably evince the kindliest interest in all hamilton's concerns. in a similar way de morgan's letters to hamilton always met with a heartfelt response. alike for the memory of hamilton, for the credit of his university, and for the benefit of science, let us hope that a collected edition of his works will ere long appear--a collection which shall show those early achievements in splendid optical theory, those achievements of his more mature powers which made him the lagrange of his country, and finally those creations of the quaternion calculus by which new capabilities have been bestowed on the human intellect. le verrier. the name of le verrier is one that goes down to fame on account of very different discoveries from those which have given renown to several of the other astronomers whom we have mentioned. we are sometimes apt to identify the idea of an astronomer with that of a man who looks through a telescope at the stars; but the word astronomer has really much wider significance. no man who ever lived has been more entitled to be designated an astronomer than le verrier, and yet it is certain that he never made a telescopic discovery of any kind. indeed, so far as his scientific achievements have been concerned, he might never have looked through a telescope at all. for the full interpretation of the movements of the heavenly bodies, mathematical knowledge of the most advanced character is demanded. the mathematician at the outset calls upon the astronomer who uses the instruments in the observatory, to ascertain for him at various times the exact positions occupied by the sun, the moon, and the planets. these observations, obtained with the greatest care, and purified as far as possible from the errors by which they may be affected form, as it were, the raw material on which the mathematician exercises his skill. it is for him to elicit from the observed places the true laws which govern the movements of the heavenly bodies. here is indeed a task in which the highest powers of the human intellect may be worthily employed. among those who have laboured with the greatest success in the interpretation of the observations made with instruments of precision, le verrier holds a highly honoured place. to him it has been given to provide a superb illustration of the success with which the mind of man can penetrate the deep things of nature. the illustrious frenchman, urban jean joseph le verrier, was born on the 11th march, 1811, at st. lo, in the department of manche. he received his education in that famous school for education in the higher branches of science, the ecole polytechnique, and acquired there considerable fame as a mathematician. on leaving the school le verrier at first purposed to devote himself to the public service, in the department of civil engineering; and it is worthy of note that his earliest scientific work was not in those mathematical researches in which he was ultimately to become so famous. his duties in the engineering department involved practical chemical research in the laboratory. in this he seems to have become very expert, and probably fame as a chemist would have been thus attained, had not destiny led him into another direction. as it was, he did engage in some original chemical research. his first contributions to science were the fruits of his laboratory work; one of his papers was on the combination of phosphorus and hydrogen, and another on the combination of phosphorus and oxygen. his mathematical labours at the ecole polytechnique had, however, revealed to le verrier that he was endowed with the powers requisite for dealing with the subtlest instruments of mathematical analysis. when he was twenty-eight years old, his first great astronomical investigation was brought forth. it will be necessary to enter into some explanation as to the nature of this, inasmuch as it was the commencement of the life-work which he was to pursue. if but a single planet revolved around the sun, then the orbit of that planet would be an ellipse, and the shape and size, as well as the position of the ellipse, would never alter. one revolution after another would be traced out, exactly in the same manner, in compliance with the force continuously exerted by the sun. suppose, however, that a second planet be introduced into the system. the sun will exert its attraction on this second planet also, and it will likewise describe an orbit round the central globe. we can, however, no longer assert that the orbit in which either of the planets moves remains exactly an ellipse. we may, indeed, assume that the mass of the sun is enormously greater than that of either of the planets. in this case the attraction of the sun is a force of such preponderating magnitude, that the actual path of each planet remains nearly the same as if the other planet were absent. but it is impossible for the orbit of each planet not to be affected in some degree by the attraction of the other planet. the general law of nature asserts that every body in space attracts every other body. so long as there is only a single planet, it is the single attraction between the sun and that planet which is the sole controlling principle of the movement, and in consequence of it the ellipse is described. but when a second planet is introduced, each of the two bodies is not only subject to the attraction of the sun, but each one of the planets attracts the other. it is true that this mutual attraction is but small, but, nevertheless, it produces some effect. it "disturbs," as the astronomer says, the elliptic orbit which would otherwise have been pursued. hence it follows that in the actual planetary system where there are several planets disturbing each other, it is not true to say that the orbits are absolutely elliptic. at the same time in any single revolution a planet may for most practical purposes be said to be actually moving in an ellipse. as, however, time goes on, the ellipse gradually varies. it alters its shape, it alters its plane, and it alters its position in that plane. if, therefore, we want to study the movements of the planets, when great intervals of time are concerned, it is necessary to have the means of learning the nature of the movement of the orbit in consequence of the disturbances it has experienced. we may illustrate the matter by supposing the planet to be running like a railway engine on a track which has been laid in a long elliptic path. we may suppose that while the planet is coursing along, the shape of the track is gradually altering. but this alteration may be so slow, that it does not appreciably affect the movement of the engine in a single revolution. we can also suppose that the plane in which the rails have been laid has a slow oscillation in level, and that the whole orbit is with more or less uniformity moved slowly about in the plane. in short periods of time the changes in the shapes and positions of the planetary orbits, in consequence of their mutual attractions, are of no great consequence. when, however, we bring thousands of years into consideration, then the displacements of the planetary orbits attain considerable dimensions, and have, in fact, produced a profound effect on the system. it is of the utmost interest to investigate the extent to which one planet can affect another in virtue of their mutual attractions. such investigations demand the exercise of the highest mathematical gifts. but not alone is intellectual ability necessary for success in such inquiries. it must be united with a patient capacity for calculations of an arduous type, protracted, as they frequently have to be, through many years of labour. le verrier soon found in these profound inquiries adequate scope for the exercise of his peculiar gifts. his first important astronomical publication contained an investigation of the changes which the orbits of several of the planets, including the earth, have undergone in times past, and which they will undergo in times to come. as an illustration of these researches, we may take the case of the planet in which we are, of course, especially interested, namely, the earth, and we can investigate the changes which, in the lapse of time, the earth's orbit has undergone, in consequence of the disturbance to which it has been subjected by the other planets. in a century, or even in a thousand years, there is but little recognisable difference in the shape of the track pursued by the earth. vast periods of time are required for the development of the large consequences of planetary perturbation. le verrier has, however, given us the particulars of what the earth's journey through space has been at intervals of 20,000 years back from the present date. his furthest calculation throws our glance back to the state of the earth's track 100,000 years ago, while, with a bound forward, he shows us what the earth's orbit is to be in the future, at successive intervals of 20,000 years, till a date is reached which is 100,000 years in advance of a.d. 1800. the talent which these researches displayed brought le verrier into notice. at that time the paris observatory was presided over by arago, a savant who occupies a distinguished position in french scientific annals. arago at once perceived that le verrier was just the man who possessed the qualifications suitable for undertaking a problem of great importance and difficulty that had begun to force itself on the attention of astronomers. what this great problem was, and how astonishing was the solution it received, must now be considered. ever since herschel brought himself into fame by his superb discovery of the great planet uranus, the movements of this new addition to the solar system were scrutinized with care and attention. the position of uranus was thus accurately determined from time to time. at length, when sufficient observations of this remote planet had been brought together, the route which the newly-discovered body pursued through the heavens was ascertained by those calculations with which astronomers are familiar. it happens, however, that uranus possesses a superficial resemblance to a star. indeed the resemblance is so often deceptive that long ere its detection as a planet by herschel, it had been observed time after time by skilful astronomers, who little thought that the star-like point at which they looked was anything but a star. from these early observations it was possible to determine the track of uranus, and it was found that the great planet takes a period of no less than eighty-four years to accomplish a circuit. calculations were made of the shape of the orbit in which it revolved before its discovery by herschel, and these were compared with the orbit which observations showed the same body to pursue in those later years when its planetary character was known. it could not, of course, be expected that the orbit should remain unaltered; the fact that the great planets jupiter and saturn revolve in the vicinity of uranus must necessarily imply that the orbit of the latter undergoes considerable changes. when, however, due allowance has been made for whatever influence the attraction of jupiter and saturn, and we may add of the earth and all the other planets, could possibly produce, the movements of uranus were still inexplicable. it was perfectly obvious that there must be some other influence at work besides that which could be attributed to the planets already known. astronomers could only recognise one solution of such a difficulty. it was impossible to doubt that there must be some other planet in addition to the bodies at that time known, and that the perturbations of uranus hitherto unaccounted for, were due to the disturbances caused by the action of this unknown planet. arago urged le verrier to undertake the great problem of searching for this body, whose theoretical existence seemed demonstrated. but the conditions of the search were such that it must needs be conducted on principles wholly different from any search which had ever before been undertaken for a celestial object. for this was not a case in which mere survey with a telescope might be expected to lead to the discovery. certain facts might be immediately presumed with reference to the unknown object. there could be no doubt that the unknown disturber of uranus must be a large body with a mass far exceeding that of the earth. it was certain, however, that it must be so distant that it could only appear from our point of view as a very small object. uranus itself lay beyond the range, or almost beyond the range, of unassisted vision. it could be shown that the planet by which the disturbance was produced revolved in an orbit which must lie outside that of uranus. it seemed thus certain that the planet could not be a body visible to the unaided eye. indeed, had it been at all conspicuous its planetary character would doubtless have been detected ages ago. the unknown body must therefore be a planet which would have to be sought for by telescopic aid. there is, of course, a profound physical difference between a planet and a star, for the star is a luminous sun, and the planet is merely a dark body, rendered visible by the sunlight which falls upon it. notwithstanding that a star is a sun thousands of times larger than the planet and millions of times more remote, yet it is a singular fact that telescopic planets possess an illusory resemblance to the stars among which their course happens to lie. so far as actual appearance goes, there is indeed only one criterion by which a planet of this kind can be discriminated from a star. if the planet be large enough the telescope will show that it possesses a disc, and has a visible and measurable circular outline. this feature a star does not exhibit. the stars are indeed so remote that no matter how large they may be intrinsically, they only exhibit radiant points of light, which the utmost powers of the telescope fail to magnify into objects with an appreciable diameter. the older and well-known planets, such as jupiter and mars, possess discs, which, though not visible to the unaided eye, were clearly enough discernible with the slightest telescopic power. but a very remote planet like uranus, though it possessed a disc large enough to be quickly appreciated by the consummate observing skill of herschel, was nevertheless so stellar in its appearance, that it had been observed no fewer than seventeen times by experienced astronomers prior to herschel. in each case the planetary nature of the object had been overlooked, and it had been taken for granted that it was a star. it presented no difference which was sufficient to arrest attention. as the unknown body by which uranus was disturbed was certainly much more remote than uranus, it seemed to be certain that though it might show a disc perceptible to very close inspection, yet that the disc must be so minute as not to be detected except with extreme care. in other words, it seemed probable that the body which was to be sought for could not readily be discriminated from a small star, to which class of object it bore a superficial resemblance, though, as a matter of fact, there was the profoundest difference between the two bodies. there are on the heavens many hundreds of thousands of stars, and the problem of identifying the planet, if indeed it should lie among these stars, seemed a very complex matter. of course it is the abundant presence of the stars which causes the difficulty. if the stars could have been got rid of, a sweep over the heavens would at once disclose all the planets which are bright enough to be visible with the telescopic power employed. it is the fortuitous resemblance of the planet to the stars which enables it to escape detection. to discriminate the planet among stars everywhere in the sky would be almost impossible. if, however, some method could be devised for localizing that precise region in which the planet's existence might be presumed, then the search could be undertaken with some prospect of success. to a certain extent the problem of localizing the region on the sky in which the planet might be expected admitted of an immediate limitation. it is known that all the planets, or perhaps i ought rather to say, all the great planets, confine their movements to a certain zone around the heavens. this zone extends some way on either side of that line called the ecliptic in which the earth pursues its journey around the sun. it was therefore to be inferred that the new planet need not be sought for outside this zone. it is obvious that this consideration at once reduces the area to be scrutinized to a small fraction of the entire heavens. but even within the zone thus defined there are many thousands of stars. it would seem a hopeless task to detect the new planet unless some further limitation to its position could be assigned. it was accordingly suggested to le verrier that he should endeavour to discover in what particular part of the strip of the celestial sphere which we have indicated the search for the unknown planet should be instituted. the materials available to the mathematician for the solution of this problem were to be derived solely from the discrepancies between the calculated places in which uranus should be found, taking into account the known causes of disturbance, and the actual places in which observation had shown the planet to exist. here was indeed an unprecedented problem, and one of extraordinary difficulty. le verrier, however, faced it, and, to the astonishment of the world, succeeded in carrying it through to a brilliant solution. we cannot here attempt to enter into any account of the mathematical investigations that were necessary. all that we can do is to give a general indication of the method which had to be adopted. let us suppose that a planet is revolving outside uranus, at a distance which is suggested by the several distances at which the other planets are dispersed around the sun. let us assume that this outer planet has started on its course, in a prescribed path, and that it has a certain mass. it will, of course, disturb the motion of uranus, and in consequence of that disturbance uranus will follow a path the nature of which can be determined by calculation. it will, however, generally be found that the path so ascertained does not tally with the actual path which observations have indicated for uranus. this demonstrates that the assumed circumstances of the unknown planet must be in some respects erroneous, and the astronomer commences afresh with an amended orbit. at last after many trials, le verrier ascertained that, by assuming a certain size, shape, and position for the unknown planet's orbit, and a certain value for the mass of the hypothetical body, it would be possible to account for the observed disturbances of uranus. gradually it became clear to the perception of this consummate mathematician, not only that the difficulties in the movements of uranus could be thus explained, but that no other explanation need be sought for. it accordingly appeared that a planet possessing the mass which he had assigned, and moving in the orbit which his calculations had indicated, must indeed exist, though no eye had ever beheld any such body. here was, indeed, an astonishing result. the mathematician sitting at his desk, by studying the observations which had been supplied to him of one planet, is able to discover the existence of another planet, and even to assign the very position which it must occupy, ere ever the telescope is invoked for its discovery. thus it was that the calculations of le verrier narrowed greatly the area to be scrutinised in the telescopic search which was presently to be instituted. it was already known, as we have just pointed out, that the planet must lie somewhere on the ecliptic. the french mathematician had now further indicated the spot on the ecliptic at which, according to his calculations, the planet must actually be found. and now for an episode in this history which will be celebrated so long as science shall endure. it is nothing less than the telescopic confirmation of the existence of this new planet, which had previously been indicated only by mathematical calculation. le verrier had not himself the instruments necessary for studying the heavens, nor did he possess the skill of the practical astronomer. he, therefore, wrote to dr. galle, of the observatory at berlin, requesting him to undertake a telescopic search for the new planet in the vicinity which the mathematical calculation had indicated for the whereabouts of the planet at that particular time. le verrier added that he thought the planet ought to admit of being recognised by the possession of a disc sufficiently definite to mark the distinction between it and the surrounding stars. it was the 23rd september, 1846, when the request from le verrier reached the berlin observatory, and the night was clear, so that the memorable search was made on the same evening. the investigation was facilitated by the circumstance that a diligent observer had recently compiled elaborate star maps for certain tracts of the heavens lying in a sufficiently wide zone on both sides of the equator. these maps were as yet only partially complete, but it happened that hora. xxi., which included the very spot which le verrier's results referred to, had been just issued. dr. galle had thus before his, eyes a chart of all the stars which were visible in that part of the heavens at the time when the map was made. the advantage of such an assistance to the search could hardly be over-estimated. it at once gave the astronomer another method of recognising the planet besides that afforded by its possible possession of a disc. for as the planet was a moving body, it would not have been in the same place relatively to the stars at the time when the map was constructed, as it occupied some years later when the search was being made. if the body should be situated in the spot which le verrier's calculations indicated in the autumn of 1846, then it might be regarded as certain that it would not be found in that same place on a map drawn some years previously. the search to be undertaken consisted in a comparison made point by point between the bodies shown on the map, and those stars in the sky which dr. galle's telescope revealed. in the course of this comparison it presently appeared that a star-like object of the eighth magnitude, which was quite a conspicuous body in the telescope, was not represented in the map. this at once attracted the earnest attention of the astronomer, and raised his hopes that here was indeed the planet. nor were these hopes destined to be disappointed. it could not be supposed that a star of the eighth magnitude would have been overlooked in the preparation of a chart whereon stars of many lower degrees of brightness were set down. one other supposition was of course conceivable. it might have been that this suspicious object belonged to the class of variables, for there are many such stars whose brightness fluctuates, and if it had happened that the map was constructed at a time when the star in question had but feeble brilliance, it might have escaped notice. it is also well known that sometimes new stars suddenly develop, so that the possibility that what dr. galle saw should have been a variable star or should have been a totally new star had to be provided against. fortunately a test was immediately available to decide whether the new object was indeed the long sought for planet, or whether it was a star of one of the two classes to which i have just referred. a star remains fixed, but a planet is in motion. no doubt when a planet lies at the distance at which this new planet was believed to be situated, its apparent motion would be so slow that it would not be easy to detect any change in the course of a single night's observation. dr. galle, however, addressed himself with much skill to the examination of the place of the new body. even in the course of the night he thought he detected slight movements, and he awaited with much anxiety the renewal of his observations on the subsequent evenings. his suspicions as to the movement of the body were then amply confirmed, and the planetary nature of the new object was thus unmistakably detected. great indeed was the admiration of the scientific world at this superb triumph. here was a mighty planet whose very existence was revealed by the indications afforded by refined mathematical calculation. at once the name of le verrier, already known to those conversant with the more profound branches of astronomy, became everywhere celebrated. it soon, however, appeared, that the fame belonging to this great achievement had to be shared between le verrier and another astronomer, j. c. adams, of cambridge. in our chapter on this great english mathematician we shall describe the manner in which he was independently led to the same discovery. directly the planetary nature of the newly-discovered body had been established, the great observatories naturally included this additional member of the solar system in their working lists, so that day after day its place was carefully determined. when sufficient time had elapsed the shape and position of the orbit of the body became known. of course, it need hardly be said that observations applied to the planet itself must necessarily provide a far more accurate method of determining the path which it follows, than would be possible to le verrier, when all he had to base his calculations upon was the influence of the planet reflected, so to speak, from uranus. it may be noted that the true elements of the planet, when revealed by direct observation, showed that there was a considerable discrepancy between the track of the planet which le verrier had announced, and that which the planet was actually found to pursue. the name of the newly-discovered body had next to be considered. as the older members of the system were already known by the same names as great heathen divinities, it was obvious that some similar source should be invoked for a suggestion as to a name for the most recent planet. the fact that this body was so remote in the depths of space, not unnaturally suggested the name "neptune." such is accordingly the accepted designation of that mighty globe which revolves in the track that at present seems to trace out the frontiers of our system. le verrier attained so much fame by this discovery, that when, in 1854, arago's place had to be filled at the head of the great paris observatory, it was universally felt that the discoverer of neptune was the suitable man to assume the office which corresponds in france to that of the astronomer royal in england. it was true that the work of the astronomical mathematician had hitherto been of an abstract character. his discoveries had been made at his desk and not in the observatory, and he had no practical acquaintance with the use of astronomical instruments. however, he threw himself into the technical duties of the observatory with vigour and determination. he endeavoured to inspire the officers of the establishment with enthusiasm for that systematic work which is so necessary for the accomplishment of useful astronomical research. it must, however, be admitted that le verrier was not gifted with those natural qualities which would make him adapted for the successful administration of such an establishment. unfortunately disputes arose between the director and his staff. at last the difficulties of the situation became so great that the only possible solution was to supersede le verrier, and he was accordingly obliged to retire. he was succeeded in his high office by another eminent mathematician, m. delaunay, only less distinguished than le verrier himself. relieved of his official duties, le verrier returned to the mathematics he loved. in his non-official capacity he continued to work with the greatest ardour at his researches on the movements of the planets. after the death of m. delaunay, who was accidentally drowned in 1873, le verrier was restored to the directorship of the observatory, and he continued to hold the office until his death. the nature of the researches to which the life of le verrier was subsequently devoted are not such as admit of description in a general sketch like this, where the language, and still less the symbols, of mathematics could not be suitably introduced. it may, however, be said in general that he was particularly engaged with the study of the effects produced on the movements of the planets by their mutual attractions. the importance of this work to astronomy consists, to a considerable extent, in the fact that by such calculations we are enabled to prepare tables by which the places of the different heavenly bodies can be predicted for our almanacs. to this task le verrier devoted himself, and the amount of work he has accomplished would perhaps have been deemed impossible had it not been actually done. the superb success which had attended le verrier's efforts to explain the cause of the perturbations of uranus, naturally led this wonderful computer to look for a similar explanation of certain other irregularities in planetary movements. to a large extent he succeeded in showing how the movements of each of the great planets could be satisfactorily accounted for by the influence of the attractions of the other bodies of the same class. one circumstance in connection with these investigations is sufficiently noteworthy to require a few words here. just as at the opening of his career, le verrier had discovered that uranus, the outermost planet of the then known system, exhibited the influence of an unknown external body, so now it appeared to him that mercury, the innermost body of our system, was also subjected to some disturbances, which could not be satisfactorily accounted for as consequences of any known agents of attraction. the ellipse in which mercury revolved was animated by a slow movement, which caused it to revolve in its plane. it appeared to le verrier that this displacement was incapable of explanation by the action of any of the known bodies of our system. he was, therefore, induced to try whether he could not determine from the disturbances of mercury the existence of some other planet, at present unknown, which revolved inside the orbit of the known planet. theory seemed to indicate that the observed alteration in the track of the planet could be thus accounted for. he naturally desired to obtain telescopic confirmation which might verify the existence of such a body in the same way as dr. galle verified the existence of neptune. if there were, indeed, an intramercurial planet, then it must occasionally cross between the earth and the sun, and might now and then be expected to be witnessed in the actual act of transit. so confident did le verrier feel in the existence of such a body that an observation of a dark object in transit, by lescarbault on 26th march, 1859, was believed by the mathematician to be the object which his theory indicated. le verrier also thought it likely that another transit of the same object would be seen in march, 1877. nothing of the kind was, however, witnessed, notwithstanding that an assiduous watch was kept, and the explanation of the change in mercury's orbit must, therefore, be regarded as still to be sought for. le verrier naturally received every honour that could be bestowed upon a man of science. the latter part of his life was passed during the most troubled period of modern french history. he was a supporter of the imperial dynasty, and during the commune he experienced much anxiety; indeed, at one time grave fears were entertained for his personal safety. early in 1877 his health, which had been gradually failing for some years, began to give way. he appeared to rally somewhat in the summer, but in september he sank rapidly, and died on sunday, the 23rd of that month. his remains were borne to the cemetery on mont parnasse in a public funeral. among his pallbearers were leading men of science, from other countries as well as france, and the memorial discourses pronounced at the grave expressed their admiration of his talents and of the greatness of the services he had rendered to science. adams. the illustrious mathematician who, among englishmen, at all events, was second only to newton by his discoveries in theoretical astronomy, was born on june the 5th, 1819, at the farmhouse of lidcot, seven miles from launceston, in cornwall. his early education was imparted under the guidance of the rev. john couch grylls, a first cousin of his mother. he appears to have received an education of the ordinary school type in classics and mathematics, but his leisure hours were largely devoted to studying what astronomical books he could find in the library of the mechanics' institute at devonport. he was twenty years old when he entered st. john's college, cambridge. his career in the university was one of almost unparalleled distinction, and it is recorded that his answering at the wranglership examination, where he came out at the head of the list in 1843, was so high that he received more than double the marks awarded to the second wrangler. among the papers found after his death was the following memorandum, dated july the 3rd, 1841: "formed a design at the beginning of this week of investigating, as soon as possible after taking my degree, the irregularities in the motion of uranus, which are as yet unaccounted for, in order to find whether they may be attributed to the action of an undiscovered planet beyond it; and, if possible, thence to determine the elements of its orbit approximately, which would lead probably to its discovery." after he had taken his degree, and had thus obtained a little relaxation from the lines within which his studies had previously been necessarily confined, adams devoted himself to the study of the perturbations of uranus, in accordance with the resolve which we have just seen that he formed while he was still an undergraduate. as a first attempt he made the supposition that there might be a planet exterior to uranus, at a distance which was double that of uranus from the sun. having completed his calculation as to the effect which such a hypothetical planet might exercise upon the movement of uranus, he came to the conclusion that it would be quite possible to account completely for the unexplained difficulties by the action of an exterior planet, if only that planet were of adequate size and had its orbit properly placed. it was necessary, however, to follow up the problem more precisely, and accordingly an application was made through professor challis, the director of the cambridge observatory, to the astronomer royal, with the object of obtaining from the observations made at greenwich observatory more accurate values for the disturbances suffered by uranus. basing his work on the more precise materials thus available, adams undertook his calculations anew, and at last, with his completed results, he called at greenwich observatory on october the 21st, 1845. he there left for the astronomer royal a paper which contained the results at which he had arrived for the mass and the mean distance of the hypothetical planet as well as the other elements necessary for calculating its exact position. [plate: john couch adams.] as we have seen in the preceding chapter, le verrier had been also investigating the same problem. the place which le verrier assigned to the hypothetical disturbing planet for the beginning of the year 1847, was within a degree of that to which adams's computations pointed, and which he had communicated to the astronomer royal seven months before le verrier's work appeared. on july the 29th, 1846, professor challis commenced to search for the unknown object with the northumberland telescope belonging to the cambridge observatory. he confined his attention to a limited region in the heavens, extending around that point to which mr. adams' calculations pointed. the relative places of all the stars, or rather star-like objects within this area, were to be carefully measured. when the same observations were repeated a week or two later, then the distances of the several pairs of stars from each other would be found unaltered, but any planet which happened to lie among the objects measured would disclose its existence by the alterations in distance due to its motion in the interval. this method of search, though no doubt it must ultimately have proved successful, was necessarily a very tedious one, but to professor challis, unfortunately, no other method was available. thus it happened that, though challis commenced his search at cambridge two months earlier than galle at berlin, yet, as we have already explained, the possession of accurate star-maps by dr. galle enabled him to discover the planet on the very first night that he looked for it. the rival claims of adams and le verrier to the discovery of neptune, or rather, we should say, the claims put forward by their respective champions, for neither of the illustrious investigators themselves condescended to enter into the personal aspect of the question, need not be further discussed here. the main points of the controversy have been long since settled, and we cannot do better than quote the words of sir john herschel when he addressed the royal astronomical society in 1848:-"as genius and destiny have joined the names of le verrier and adams, i shall by no means put them asunder; nor will they ever be pronounced apart so long as language shall celebrate the triumphs of science in her sublimest walks. on the great discovery of neptune, which may be said to have surpassed, by intelligible and legitimate means, the wildest pretensions of clairvoyance, it would now be quite superfluous for me to dilate. that glorious event and the steps which led to it, and the various lights in which it has been placed, are already familiar to every one having the least tincture of science. i will only add that as there is not, nor henceforth ever can be, the slightest rivalry on the subject between these two illustrious men--as they have met as brothers, and as such will, i trust, ever regard each other--we have made, we could make, no distinction between then, on this occasion. may they both long adorn and augment our science, and add to their own fame already so high and pure, by fresh achievements." adams was elected a fellow of st. john's college, cambridge, in 1843; but as he did not take holy orders, his fellowship, in accordance with the rules then existing came to an end in 1852. in the following year he was, however, elected to a fellowship at pembroke college, which he retained until the end of his life. in 1858 he was appointed professor of mathematics in the university of st. andrews, but his residence in the north was only a brief one, for in the same year he was recalled to cambridge as lowndean professor of astronomy and geometry, in succession to peacock. in 1861 challis retired from the directorship of the cambridge observatory, and adams was appointed to succeed him. the discovery of neptune was a brilliant inauguration of the astronomical career of adams. he worked at, and wrote upon, the theory of the motions of biela's comet; he made important corrections to the theory of saturn; he investigated the mass of uranus, a subject in which he was naturally interested from its importance in the theory of neptune; he also improved the methods of computing the orbits of double stars. but all these must be regarded as his minor labours, for next to the discovery of neptune the fame of adams mainly rests on his researches upon certain movements of the moon, and upon the november meteors. the periodic time of the moon is the interval required for one circuit of its orbit. this interval is known with accuracy at the present day, and by means of the ancient eclipses the period of the moon's revolution two thousand years ago can be also ascertained. it had been discovered by halley that the period which the moon requires to accomplish each of its revolutions around the earth has been steadily, though no doubt slowly, diminishing. the change thus produced is not appreciable when only small intervals of time are considered, but it becomes appreciable when we have to deal with intervals of thousands of years. the actual effect which is produced by the lunar acceleration, for so this phenomenon is called, may be thus estimated. if we suppose that the moon had, throughout the ages, revolved around the earth in precisely the same periodic time which it has at present, and if from this assumption we calculate back to find where the moon must have been about two thousand years ago, we obtain a position which the ancient eclipses show to be different from that in which the moon was actually situated. the interval between the position in which the moon would have been found two thousand years ago if there had been no acceleration, and the position in which the moon was actually placed, amounts to about a degree, that is to say, to an arc on the heavens which is twice the moon's apparent diameter. if no other bodies save the earth and the moon were present in the universe, it seems certain that the motion of the moon would never have exhibited this acceleration. in such a simple case as that which i have supposed the orbit of the moon would have remained for ever absolutely unchanged. it is, however, well known that the presence of the sun exerts a disturbing influence upon the movements of the moon. in each revolution our satellite is continually drawn aside by the action of the sun from the place which it would otherwise have occupied. these irregularities are known as the perturbations of the lunar orbit, they have long been studied, and the majority of them have been satisfactorily accounted for. it seems, however, to those who first investigated the question that the phenomenon of the lunar acceleration could not be explained as a consequence of solar perturbation, and, as no other agent competent to produce such effects was recognised by astronomers, the lunar acceleration presented an unsolved enigma. at the end of the last century the illustrious french mathematician laplace undertook a new investigation of the famous problem, and was rewarded with a success which for a long time appeared to be quite complete. let us suppose that the moon lies directly between the earth and the sun, then both earth and moon are pulled towards the sun by the solar attraction; as, however, the moon is the nearer of the two bodies to the attracting centre it is pulled the more energetically, and consequently there is an increase in the distance between the earth and the moon. similarly when the moon happens to lie on the other side of the earth, so that the earth is interposed directly between the moon and the sun, the solar attraction exerted upon the earth is more powerful than the same influence upon the moon. consequently in this case, also, the distance of the moon from the earth is increased by the solar disturbance. these instances will illustrate the general truth, that, as one of the consequences of the disturbing influence exerted by the sun upon the earth-moon system, there is an increase in the dimensions of the average orbit which the moon describes around the earth. as the time required by the moon to accomplish a journey round the earth depends upon its distance from the earth, it follows that among the influences of the sun upon the moon there must be an enlargement of the periodic time, from what it would have been had there been no solar disturbing action. this was known long before the time of laplace, but it did not directly convey any explanation of the lunar acceleration. it no doubt amounted to the assertion that the moon's periodic time was slightly augmented by the disturbance, but it did not give any grounds for suspecting that there was a continuous change in progress. it was, however, apparent that the periodic time was connected with the solar disturbance, so that, if there were any alteration in the amount of the sun's disturbing effect, there must be a corresponding alteration in the moon's periodic time. laplace, therefore, perceived that, if he could discover any continuous change in the ability of the sun for disturbing the moon, he would then have accounted for a continuous change in the moon's periodic time, and that thus an explanation of the long-vexed question of the lunar acceleration might be forthcoming. the capability of the sun for disturbing the earth-moon system is obviously connected with the distance of the earth from the sun. if the earth moved in an orbit which underwent no change whatever, then the efficiency of the sun as a disturbing agent would not undergo any change of the kind which was sought for. but if there were any alteration in the shape or size of the earth's orbit, then that might involve such changes in the distance between the earth and the sun as would possibly afford the desired agent for producing the observed lunar effect. it is known that the earth revolves in an orbit which, though nearly circular, is strictly an ellipse. if the earth were the only planet revolving around the sun then that ellipse would remain unaltered from age to age. the earth is, however, only one of a large number of planets which circulate around the great luminary, and are guided and controlled by his supreme attracting power. these planets mutually attract each other, and in consequence of their mutual attractions the orbits of the planets are disturbed from the simple elliptic form which they would otherwise possess. the movement of the earth, for instance, is not, strictly speaking, performed in an elliptical orbit. we may, however, regard it as revolving in an ellipse provided we admit that the ellipse is itself in slow motion. it is a remarkable characteristic of the disturbing effects of the planets that the ellipse in which the earth is at any moment moving always retains the same length; that is to say, its longest diameter is invariable. in all other respects the ellipse is continually changing. it alters its position, it changes its plane, and, most important of all, it changes its eccentricity. thus, from age to age the shape of the track which the earth describes may at one time be growing more nearly a circle, or at another time may be departing more widely from a circle. these alterations are very small in amount, and they take place with extreme slowness, but they are in incessant progress, and their amount admits of being accurately calculated. at the present time, and for thousands of years past, as well as for thousands of years to come, the eccentricity of the earth's orbit is diminishing, and consequently the orbit described by the earth each year is becoming more nearly circular. we must, however, remember that under all circumstances the length of the longest axis of the ellipse is unaltered, and consequently the size of the track which the earth describes around the sun is gradually increasing. in other words, it may be said that during the present ages the average distance between the earth and the sun is waxing greater in consequence of the perturbations which the earth experiences from the attraction of the other planets. we have, however, already seen that the efficiency of the solar attraction for disturbing the moon's movement depends on the distance between the earth and the sun. as therefore the average distance between the earth and the sun is increasing, at all events during the thousands of years over which our observations extend, it follows that the ability of the sun for disturbing the moon must be gradually diminishing. [plate: cambridge observatory.] it has been pointed out that, in consequence of the solar disturbance, the orbit of the moon must be some what enlarged. as it now appears that the solar disturbance is on the whole declining, it follows that the orbit of the moon, which has to be adjusted relatively to the average value of the solar disturbance, must also be gradually declining. in other words, the moon must be approaching nearer to the earth in consequence of the alterations in the eccentricity of the earth's orbit produced by the attraction of the other planets. it is true that the change in the moon's position thus arising is an extremely small one, and the consequent effect in accelerating the moon's motion is but very slight. it is in fact almost imperceptible, except when great periods of time are involved. laplace undertook a calculation on this subject. he knew what the efficiency of the planets in altering the dimensions of the earth's orbit amounted to; from this he was able to determine the changes that would be propagated into the motion of the moon. thus he ascertained, or at all events thought he had ascertained, that the acceleration of the moon's motion, as it had been inferred from the observations of the ancient eclipses which have been handed down to us, could be completely accounted for as a consequence of planetary perturbation. this was regarded as a great scientific triumph. our belief in the universality of the law of gravitation would, in fact, have been seriously challenged unless some explanation of the lunar acceleration had been forthcoming. for about fifty years no one questioned the truth of laplace's investigation. when a mathematician of his eminence had rendered an explanation of the remarkable facts of observation which seemed so complete, it is not surprising that there should have been but little temptation to doubt it. on undertaking a new calculation of the same question, professor adams found that laplace had not pursued this approximation sufficiently far, and that consequently there was a considerable error in the result of his analysis. adams, it must be observed, did not impugn the value of the lunar acceleration which halley had deduced from the observations, but what he did show was, that the calculation by which laplace thought he had provided an explanation of this acceleration was erroneous. adams, in fact, proved that the planetary influence which laplace had detected only possessed about half the efficiency which the great french mathematician had attributed to it. there were not wanting illustrious mathematicians who came forward to defend the calculations of laplace. they computed the question anew and arrived at results practically coincident with those he had given. on the other hand certain distinguished mathematicians at home and abroad verified the results of adams. the issue was merely a mathematical one. it had only one correct solution. gradually it appeared that those who opposed adams presented a number of different solutions, all of them discordant with his, and, usually, discordant with each other. adams showed distinctly where each of these investigators had fallen into error, and at last it became universally admitted that the cambridge professor had corrected laplace in a very fundamental point of astronomical theory. though it was desirable to have learned the truth, yet the breach between observation and calculation which laplace was believed to have closed thus became reopened. laplace's investigation, had it been correct, would have exactly explained the observed facts. it was, however, now shown that his solution was not correct, and that the lunar acceleration, when strictly calculated as a consequence of solar perturbations, only produced about half the effect which was wanted to explain the ancient eclipses completely. it now seems certain that there is no means of accounting for the lunar acceleration as a direct consequence of the laws of gravitation, if we suppose, as we have been in the habit of supposing, that the members of the solar system concerned may be regarded as rigid particles. it has, however, been suggested that another explanation of a very interesting kind may be forthcoming, and this we must endeavour to set forth. it will be remembered that we have to explain why the period of revolution of the moon is now shorter than it used to be. if we imagine the length of the period to be expressed in terms of days and fractions of a day, that is to say, in terms of the rotations of the earth around its axis, then the difficulty encountered is, that the moon now requires for each of its revolutions around the earth rather a smaller number of rotations of the earth around its axis than used formerly to be the case. of course this may be explained by the fact that the moon is now moving more swiftly than of yore, but it is obvious that an explanation of quite a different kind might be conceivable. the moon may be moving just at the same pace as ever, but the length of the day may be increasing. if the length of the day is increasing, then, of course, a smaller number of days will be required for the moon to perform each revolution even though the moon's period was itself really unchanged. it would, therefore, seem as if the phenomenon known as the lunar acceleration is the result of the two causes. the first of these is that discovered by laplace, though its value was over-estimated by him, in which the perturbations of the earth by the planets indirectly affect the motion of the moon. the remaining part of the acceleration of our satellite is apparent rather than real, it is not that the moon is moving more quickly, but that our time-piece, the earth, is revolving more slowly, and is thus actually losing time. it is interesting to note that we can detect a physical explanation for the apparent checking of the earth's motion which is thus manifested. the tides which ebb and flow on the earth exert a brake-like action on the revolving globe, and there can be no doubt that they are gradually reducing its speed, and thus lengthening the day. it has accordingly been suggested that it is this action of the tides which produces the supplementary effect necessary to complete the physical explanation of the lunar acceleration, though it would perhaps be a little premature to assert that this has been fully demonstrated. the third of professor adams' most notable achievements was connected with the great shower of november meteors which astonished the world in 1866. this splendid display concentrated the attention of astronomers on the theory of the movements of the little objects by which the display was produced. for the definite discovery of the track in which these bodies revolve, we are indebted to the labours of professor adams, who, by a brilliant piece of mathematical work, completed the edifice whose foundations had been laid by professor newton, of yale, and other astronomers. meteors revolve around the sun in a vast swarm, every individual member of which pursues an orbit in accordance with the well-known laws of kepler. in order to understand the movements of these objects, to account satisfactorily for their periodic recurrence, and to predict the times of their appearance, it became necessary to learn the size and the shape of the track which the swarm followed, as well as the position which it occupied. certain features of the track could no doubt be readily assigned. the fact that the shower recurs on one particular day of the year, viz., november 13th, defines one point through which the orbit must pass. the position on the heavens of the radiant point from which the meteors appear to diverge, gives another element in the track. the sun must of course be situated at the focus, so that only one further piece of information, namely, the periodic time, will be necessary to complete our knowledge of the movements of the system. professor h. newton, of yale, had shown that the choice of possible orbits for the meteoric swarm is limited to five. there is, first, the great ellipse in which we now know the meteors revolve once every thirty three and one quarter years. there is next an orbit of a nearly circular kind in which the periodic time would be a little more than a year. there is a similar track in which the periodic time would be a few days short of a year, while two other smaller orbits would also be conceivable. professor newton had pointed out a test by which it would be possible to select the true orbit, which we know must be one or other of these five. the mathematical difficulties which attended the application of this test were no doubt great, but they did not baffle professor adams. there is a continuous advance in the date of this meteoric shower. the meteors now cross our track at the point occupied by the earth on november 13th, but this point is gradually altering. the only influence known to us which could account for the continuous change in the plane of the meteor's orbit arises from the attraction of the various planets. the problem to be solved may therefore be attacked in this manner. a specified amount of change in the plane of the orbit of the meteors is known to arise, and the changes which ought to result from the attraction of the planets can be computed for each of the five possible orbits, in one of which it is certain that the meteors must revolve. professor adams undertook the work. its difficulty principally arises from the high eccentricity of the largest of the orbits, which renders the more ordinary methods of calculation inapplicable. after some months of arduous labour the work was completed, and in april, 1867, adams announced his solution of the problem. he showed that if the meteors revolved in the largest of the five orbits, with the periodic time of thirty three and one quarter years, the perturbations of jupiter would account for a change to the extent of twenty minutes of arc in the point in which the orbit crosses the earth's track. the attraction of saturn would augment this by seven minutes, and uranus would add one minute more, while the influence of the earth and of the other planets would be inappreciable. the accumulated effect is thus twenty-eight minutes, which is practically coincident with the observed value as determined by professor newton from an examination of all the showers of which there is any historical record. having thus showed that the great orbit was a possible path for the meteors, adams next proved that no one of the other four orbits would be disturbed in the same manner. indeed, it appeared that not half the observed amount of change could arise in any orbit except in that one with the long period. thus was brought to completion the interesting research which demonstrated the true relation of the meteor swarm to the solar system. besides those memorable scientific labours with which his attention was so largely engaged, professor adams found time for much other study. he occasionally allowed himself to undertake as a relaxation some pieces of numerical calculation, so tremendously long that we can only look on them with astonishment. he has calculated certain important mathematical constants accurately to more than two hundred places of decimals. he was a diligent reader of works on history, geology, and botany, and his arduous labours were often beguiled by novels, of which, like many other great men, he was very fond. he had also the taste of a collector, and he brought together about eight hundred volumes of early printed works, many of considerable rarity and value. as to his personal character, i may quote the words of dr. glaisher when he says, "strangers who first met him were invariably struck by his simple and unaffected manner. he was a delightful companion, always cheerful and genial, showing in society but few traces of his really shy and retiring disposition. his nature was sympathetic and generous, and in few men have the moral and intellectual qualities been more perfectly balanced." in 1863 he married the daughter of haliday bruce, esq., of dublin and up to the close of his life he lived at the cambridge observatory, pursuing his mathematical work and enjoying the society of his friends. he died, after a long illness, on 21st january, 1892, and was interred in st. giles's cemetery, on the huntingdon road, cambridge. the reminiscences of an astronomer by simon newcomb 1903 preface the earlier chapters of this collection are so much in the nature of an autobiography that the author has long shrunk from the idea of allowing them to see the light during his lifetime. his repugnance has been overcome by very warm expressions on the subject uttered by valued friends to whom they were shown, and by a desire that some at least who knew him in youth should be able to read what he has written. the author trusts that neither critic nor reader will object because he has, in some cases, strayed outside the limits of his purely personal experience, in order to give a more complete view of a situation, or to bring out matters that might be of historic interest. if some of the chapters are scrappy, it is because he has tried to collect those experiences which have afforded him most food for thought, have been most influential in shaping his views, or are recalled with most pleasure. contents i the world of cold and darkness ancestry.--squire thomas prince.--parentage.--early education.- books read. ii dr. foshay a long journey on foot.--a wonderful doctor.--the botanic system of medicine.--phrenology.--a launch into the world.--a disillusion.- life in maryland.--acquaintance with professor henry.--removal to cambridge. iii the world of sweetness and light the american astronomical ephemeris.--the men who made it.- harvard in the middle of the century.--a librarian of the time.- professor peirce.--dr. gould, the "astronomical journal," and the dudley observatory.--w. p. g. bartlett.--john d. runkle and the "mathematical monthly."--a mathematical politician.--a trip to manitoba and a voyage up the saskatchewan.--a wonderful star. iv life and work at an observatory a professor, united states navy.--the naval observatory in 1861.- captain gilliss and his plans.--admiral davis.--a new instrument and a new departure.--astronomical activity.--the question of observatory administration.--visit from the emperor of brazil.- admiral john rodgers.--efforts to improve the work of the observatory. v great telescopes and their work curious origin of the great washington telescope.--congress is induced to act.--a case of astronomical fallibility.- the discovery of the satellites of mars.--the great telescope of the pulkova observatory.--alvan clark and his sons.--a sad astronomical accident. vi the transits of venus old transits of venus.--an astronomical expedition in the 18th century.--father hell and his observations.--a suspected forger vindicated.--the american commission on the transit of venus.- the photographic method to be applied.--garfield and the appropriation committee.--weather uncertainties.--voyage to the cape of good hope.--the transit of 1882.--our failure to publish our observations. vii the lick observatory james lick and his ideas.--mr. d. o. mills.--plans for the lick observatory.--edward e. barnard.--professor holden.--wonderful success of the observatory. viii the author's scientific work the orbits of the asteroids.--the problems of mathematical astronomy.--the motion of the moon and its perplexing inequalities.--a visit to the paris observatory to search for forgotten observations.--wonderful success in finding them.- the paris commune.--the history of the moon's motion carried back a century.--the harvard observatory.--the "nautical almanac" office and its work.--mr. george w. hill and his work.--a wonderful algebraist.--the meridian conference of 1884, and the question of universal time.--tables of the planets completed.- the astronomical constants.--work unfinished. ix scientific washington professor henry and the smithsonian institution.- alumni associations.--the scientific club.--general sherman.- mr. hugh mcculloch.--a forgotten scientist.--the national academy of sciences.--the geological survey of the territories.--the government forestry system.--professor o. c. marsh.--scientific humbugs.- life on the plains. x scientific england my first trip to europe.--mr. thomas hughes.--mr. john stuart mill. --mr. gladstone and the royal society dinner.--other eminent englishmen.--professors cayley and adams.--professor airy and the greenwich observatory.--a visit to edinburgh. xi men and things in europe a voyage to gibraltar with professor tyndall.--the great fortress. --"whispering boanerges."--a winter voyage in the mediterranean.- malta and messina.--advantage of not understanding a language.- german astronomers.--the pulkova observatory.--a meeting which might have been embarrassing.--from germany to paris at the close of the war.--experiences at paris during the commune.--the greatest astronomer of france.--the paris observatory. xii the old and the new washington washington during the civil war.--secretary stanton.- the raid of general early.--a presidential levee in 1864.- the fall of richmond.--the assassination of president lincoln.- negro traits and education.--senator sumner.--an ambitious academy. --president garfield and his assassination.--cooling the white house during his illness.--the shepherd régime in washington. xiii miscellanea the great star-catalogue case.--professor peters and the almagest of ptolemy.--scientific cranks.--the degrees of the french universities.--a virginia country school.--political economy and education.--exact science in america before the johns hopkins university.--professor ely and economics.--spiritualism and psychic research.--the georgia magnetic girl. the reminiscences of an astronomer i the world of cold and darkness i date my birth into the world of sweetness and light on one frosty morning in january, 1857, when i took my seat between two well-known mathematicians, before a blazing fire in the office of the "nautical almanac" at cambridge, mass. i had come on from washington, armed with letters from professor henry and mr. hilgard, to seek a trial as an astronomical computer. the men beside me were professor joseph winlock, the superintendent, and mr. john d. runkle, the senior assistant in the office. i talked of my unsuccessful attempt to master the "mécanique céleste" of laplace without other preparation than that afforded by the most meagre text-books of elementary mathematics of that period. runkle spoke of the translator as "the captain." so familiar a designation of the great bowditch--ll. d. and a member of the royal societies of london, edinburgh, and dublin--quite shocked me. i was then in my twenty-second year, but it was the first time i had ever seen any one who was familiar with the "mécanique céleste." i looked with awe upon the assistants who filed in and out as upon men who had all the mysteries of gravitation and the celestial motions at their fingers' ends. i should not have been surprised to learn that even the hibernian who fed the fire had imbibed so much of the spirit of the place as to admire the genius of laplace and lagrange. my own rank was scarcely up to that of a tyro; but i was a few weeks later employed on trial as computer at a salary of thirty dollars a month. how could an incident so simple and an employment so humble be in itself an epoch in one's life--an entrance into a new world? to answer this question some account of my early life is necessary. the interest now taken in questions of heredity and in the study of the growing mind of the child may excuse a word about my ancestry and early training. though born in nova scotia, i am of almost pure new england descent. the first simon newcomb, from whom i am of the sixth generation, was born in massachusetts or maine about 1666, and died at lebanon, conn., in 1745. his descendants had a fancy for naming their eldest sons after him, and but for the chance of my father being a younger son, i should have been the sixth simon in unbroken lineal descent. [1] among my paternal ancestors none, so far as i know, with the exception of elder brewster, were what we should now call educated men. nor did any other of them acquire great wealth, hold a high official position, or do anything to make his name live in history. on my mother's side are found new england clergymen and an english nonconformist preacher, named prince, who is said to have studied at oxford towards the end of the seventeenth century, but did not take a degree. i do not know of any college graduate in the list. until i was four years old i lived in the house of my paternal grandfather, about two miles from the pretty little village of wallace, at the mouth of the river of that name. he was, i believe, a stonecutter by trade and owner of a quarry which has since become important; but tradition credits him with unusual learning and with having at some time taught school. my maternal grandfather was "squire" thomas prince, a native of maine, who had moved to moncton, n. b., early in his life, and lived there the rest of his days. he was an upright magistrate, a puritan in principle, and a pillar of the baptist church, highly respected throughout the province. he came from a long-lived family, and one so prolific that it is said most of the princes of new england are descended from it. i have heard a story of him which may illustrate the freedom of the time in matters of legal proceedings before a magistrate's court. at that time a party in a suit could not be a witness. in the terse language of the common people, "no man could swear money into his own pocket." the plaintiff in the case advised the magistrate in advance that he had no legal proof of the debt, but that defendant freely acknowledged it in private conversation. "well," said the magistrate, "bring him in here and get him to talk about it while i am absent." the time came. "if you had n't sued me i would have paid you," said the defendant. on the moment the magistrate stepped from behind a door with the remark,-"i think you will pay him now, whether or no." my father was the most rational and the most dispassionate of men. the conduct of his life was guided by a philosophy based on combe's "constitution of man," and i used to feel that the law of the land was a potent instrument in shaping his paternal affections. his method of seeking a wife was so far unique that it may not be devoid of interest, even at this date. from careful study he had learned that the age at which a man should marry was twenty-five. a healthy and well-endowed offspring should be one of the main objects in view in entering the marriage state, and this required a mentally gifted wife. she must be of different temperament from his own and an economical housekeeper. so when he found the age of twenty-five approaching, he began to look about. there was no one in wallace who satisfied the requirements. he therefore set out afoot to discover his ideal. in those days and regions the professional tramp and mendicant were unknown, and every farmhouse dispensed its hospitality with an arcadian simplicity little known in our times. wherever he stopped overnight he made a critical investigation of the housekeeping, perhaps rising before the family for this purpose. he searched in vain until his road carried him out of the province. one young woman spoiled any possible chance she might have had by a lack of economy in the making of bread. she was asked what she did with an unnecessarily large remnant of dough which she left sticking to the sides of the pan. she replied that she fed it to the horses. her case received no further consideration. the search had extended nearly a hundred miles when, early one evening, he reached what was then the small village of moncton. he was attracted by the strains of music from a church, went into it, and found a religious meeting in progress. his eye was at once arrested by the face and head of a young woman playing on a melodeon, who was leading the singing. he sat in such a position that he could carefully scan her face and movements. as he continued this study the conviction grew upon him that here was the object of his search. that such should have occurred before there was any opportunity to inspect the doughpan may lead the reader to conclusions of his own. he inquired her name--emily prince. he cultivated her acquaintance, paid his addresses, and was accepted. he was fond of astronomy, and during the months of his engagement one of his favorite occupations was to take her out of an evening and show her the constellations. it is even said that, among the daydreams in which they indulged, one was that their firstborn might be an astronomer. probably this was only a passing fancy, as i heard nothing of it during my childhood. the marriage was in all respects a happy one, so far as congeniality of nature and mutual regard could go. although the wife died at the early age of thirty-seven, the husband never ceased to cherish her memory, and, so far as i am aware, never again thought of marrying. my mother was the most profoundly and sincerely religious woman with whom i was ever intimately acquainted, and my father always entertained and expressed the highest admiration for her mental gifts, to which he attributed whatever talents his children might have possessed. the unfitness of her environment to her constitution is the saddest memory of my childhood. more i do not trust myself to say to the public, nor will the reader expect more of me. my father followed, during most of his life, the precarious occupation of a country school teacher. it was then, as it still is in many thinly settled parts of the country, an almost nomadic profession, a teacher seldom remaining more than one or two years in the same place. thus it happened that, during the first fifteen years of my life, movings were frequent. my father tried his fortune in a number of places, both in nova scotia and prince edward island. our lot was made harder by the fact that his ideas of education did not coincide with those prevalent in the communities where he taught. he was a disciple and admirer of william cobbett, and though he did not run so far counter to the ideas of his patrons as to teach cobbett's grammar at school, he always recommended it to me as the one by which alone i could learn to write good english. the learning of anything, especially of arithmetic and grammar, by the glib repetition of rules was a system that he held in contempt. with the public, ability to recite the rules of such subjects as those went farther than any actual demonstration of the power to cipher correctly or write grammatically. so far as the economic condition of society and the general mode of living and thinking were concerned, i might claim to have lived in the time of the american revolution. a railway was something read or heard about with wonder; a steamer had never ploughed the waters of wallace bay. nearly everything necessary for the daily life of the people had to be made on the spot, and even at home. the work of the men and boys was "from sun to sun,"--i might almost say from daylight to darkness,--as they tilled the ground, mended the fences, or cut lumber, wood, and stone for export to more favored climes. the spinning wheel and the loom were almost a necessary part of the furniture of any well-ordered house; the exceptions were among people rich enough to buy their own clothes, or so poor and miserable that they had to wear the cast-off rags of their more fortunate neighbors. the women and girls sheared the sheep, carded the wool, spun the yarn, wove the homespun cloth, and made the clothes. in the haying season they amused themselves by joining in the raking of hay, in which they had to be particularly active if rain was threatened; but any man would have lost caste who allowed wife or daughter to engage in heavy work outside the house. the contrast between the social conditions and those which surround even the poorest classes at the present day have had a profound influence upon my views of economic subjects. the conception which the masses of the present time have of how their ancestors lived in the early years of the century are so vague and shadowy as not to influence their conduct at the present time. what we now call school training, the pursuit of fixed studies at stated hours under the constant guidance of a teacher, i could scarcely be said to have enjoyed. for the most part, when i attended my father's school at all, i came and went with entire freedom, and this for causes which, as we shall see, he had reasons for deeming good. it would seem that i was rather precocious. i was taught the alphabet by my aunts before i was four years old, and i was reading the bible in class and beginning geography when i was six. one curious feature of my reading i do not remember to have seen noticed in the case of children. the printed words, for the most part, brought no well-defined images to my mind; none at least that were retained in their connection. i remember one instance of this. we were at bedeque, prince edward island. during the absence of my father, the school was kept for a time by mr. bacon. the class in reading had that chapter in the new testament in which the treason of judas is described. it was then examined on the subject. to the question what judas did, no one could return an answer until it came my turn. i had a vague impression of some one hanging himself, and so i said quite at random that he hanged himself. it was with a qualm of conscience that i went to the head of the class. arithmetic was commenced at the age of five, my father drawing me to school day by day on a little sled during the winter. just what progress i made at that time i do not recall. long years afterward, my father, at my request, wrote me a letter describing my early education, extracts from which i shall ask permission to reproduce, instead of attempting to treat the matter myself. the letter, covering twelve closely written foolscap pages, was probably dashed off at a sitting without supposing any eye but my own would ever see it:- june 8th, '58. i will now proceed to write, according to your request, about your early life. while in your fifth year, your mother spoke several times of the propriety of teaching you the first rudiments of book-learning; but i insisted that you should not be taught the first letter until you became five. [2] i think, though, that at about four, or four and a half i taught you to count, as far, perhaps, as 100. when a little over four and a half, one evening, as i came home from school, you ran to me, and asked, "father, is not 4 and 4 and 4 and 4, 16?" "yes, how did you find it out?" you showed me the counterpane which was napped. the spot of four rows each way was the one you had counted up. after this, for a week or two, you spent a considerable number of hours every day, making calculations in addition and multiplication. the rows of naps being crossed and complexed in various ways, your greatest delight was to clear them out, find how many small ones were equal to one large one, and such like. after a space of two or three weeks we became afraid you would calculate yourself "out of your head," and laid away the counterpane. winter came, and passed along, and your birthday came; on that day, having a light hand-sled prepared, i fixed you on it, and away we went a mile and a half to school. according to my belief in educational matters "that the slate should be put into the child's hands as soon as the book is," you of course had your slate, and commenced making figures and letters the first day. in all cases, after you had read and spelled a lesson, and made some figures, and worked a sum, suppose one hour's study, i sent you out, telling you to run about and play a "good spell." to the best of my judgment you studied, during the five months that this school lasted, nearly four hours a day, two being at figures. * * * * * during the year that i taught at bedeque, you studied about five hours a day in school; and i used to exercise you about an hour a day besides, either morning or evening. this would make six hours per day, nearly or quite two and a half hours of that time at numbers either at your slate or mentally. when my school ended here, you were six and a half years of age, and pretty well through the arithmetic. you had studied, i think, all the rules preceding including the cube root. . . . i had frequently heard, during my boyhood, of a supposed mental breakdown about this period, and had asked my father for a description of it in the letter from which i am quoting. on this subject the letter continues:- you had lost all relish for reading, study, play, or talk. sat most of the day flat on the floor or hearth. when sent of an errand, you would half the time forget what you went for. i have seen you come back from cale schurman's crying, [3] and after asking you several times you would make out to answer, you had not been all the way over because you forgot what you went for. you would frequently jump up from the corner, and ask some peculiar question. i remember three you asked me. 1st. father, does form mean shape? yes. has everything some shape? yes. can it be possible for anything to be made that would not have any shape? i answered no; and then showed you several things, explaining that they all had some shape or form. you now brightened up like a lawyer who had led on a witness with easy questions to a certain point, and who had cautiously reserved a thunderbolt question, to floor the witness at a proper time; proceeded with, "well, then, how could the world be without form when god made it?" * * * * * 3d. does cale schurman's big ram know that he has such big crooked horns on him? does he know it himself, i mean? does he know himself that he has such horns on him? you were taken down suddenly i think about two or three days from the first symptoms until you were fairly in the corner. your rise was also rapid, i think about a week (or perhaps two weeks) from your first at recovery, until you seemed to show nothing unusual. from the time you were taken down until you commenced recovery was about a month. we returned to prince edward island, and after a few weeks i began to examine you in figures, and found you had forgotten nearly all you had ever learned. * * * * * while at new london i got an old work on astronomy; you were wonderfully taken with it, and read it with avidity. while here you read considerable in "goldsmith's history of england." we lived two years in new london; i think you attended school nearly one year there. i usually asked you questions on the road going to school, in the morning, upon the history you had read, or something you had studied the day previous. while there, you made a dozen or two of the folks raise a terrible laugh. i one evening lectured on astronomy at home; the house was pretty well filled, i suppose about twenty were present. you were not quite ten years old and small at that. almost as soon as i was done you said: "father, i think you were wrong in one thing." such a roar of laughter almost shook the house. you were an uncommon child for _truth_. i never knew you to deviate from it in one single instance, either in infancy or youth. from your infancy you showed great physical courage in going along the woods or in places in the dark among cattle, and i am surprised at what you say about your fears of a stove-pipe and trees. perhaps i should have said "mental" instead of physical courage, for in one respect you were uncommonly deficient in that sort of courage necessary to perform bodily labor. until nine or ten years of age you made a most pitiful attempt at any sort of bodily or rather "handy" work. * * * * * an extraordinary peculiarity in you was never to leap past a word you could not make out. i certainly never gave you any particular instructions about this, or the fact itself would not at the time have appeared so strange to me. i will name one case. after a return to wallace (you were eleven) i, one day, on going from home for an hour or so, gave you a borrowed newspaper, telling you there was a fine piece; to read it, and tell me its contents when i returned. on my return you were near the house chopping wood. "well, simon, did you read the piece?" "no, sir." "why not?" "i came to a word i did not know." this word was just about four lines from the commencement. at thirteen you read phrenology. i now often impressed upon you the necessity of bodily labor; that you might attain a strong and healthy physical system, so as to be able to stand long hours of study when you came to manhood, for it was evident to me that you would not labor with the hands for a business. on this account, as much as on account of poverty, i hired you out for a large portion of the three years that we lived at clements. at fifteen you studied euclid, and were enraptured with it. it is a little singular that all this time you never showed any self-esteem; or spoke of getting into employment at some future day, among the learned. the pleasure of intellectual exercise in demonstrating or analyzing a geometrical problem, or solving an algebraic equation, seemed to be your only object. no junior, seignour or sophomore class, with annual honors, was ever, i suppose, presented to your mind. your almost intuitive knowledge of geography, navigation, and nautical matters in general caused me to think most ardently of writing to the admiral at halifax, to know if he would give you a place among the midshipmen of the navy; but my hope of seeing you a leading lawyer, and finally a judge on the bench, together with the possibility that your mother would not consent, and the possibility that you would not wish to go, deterred me: although i think i commenced a letter. among the books which profoundly influenced my mode of life and thought during the period embraced in the foregoing extracts were fowler's "phrenology" and combe's "constitution of man." it may appear strange to the reader if a system so completely exploded as that of phrenology should have any value as a mental discipline. its real value consisted, not in what it taught about the position of the "organs," but in presenting a study of human nature which, if not scientific in form, was truly so in spirit. i acquired the habit of looking on the characters and capabilities of men as the result of their organism. a hot and impulsive temper was checked by the reflection that it was beneath the dignity of human nature to allow a rush of blood to the organs of "combativeness" and "destructiveness" to upset one's mental equilibrium. that i have gotten along in life almost without making (so far as i am aware) a personal enemy may be attributed to this early discipline, which led me into the habit of dealing with antagonism and personal opposition as i would deal with any physical opposition--evade it, avoid it, or overcome it. it goes without saying, however, that no discipline of this sort will avail to keep the passions of a youth always in check, and my own were no exception. when about fifteen i once made a great scandal by taking out my knife in prayer meeting and assaulting a young man who, while i was kneeling down during the prayer, stood above me and squeezed my neck. he escaped with a couple of severe though not serious cuts in his hand. he announced his intention of thrashing me when we should meet again; so for several days thereafter i tried, so far as possible, in going afield to keep a pitchfork within reach, determined that if he tried the job and i failed to kill him, it would be because i was unable to do so. fortunately for both of us he never made the attempt. i read combe's "constitution of man" when between ten and twelve years of age. though based on the ideas of phrenology and not, i believe, of high repute as a system of philosophy, it was as good a moral tonic as i can imagine to be placed in the hands of a youth, however fallacious may have been its general doctrines. so far as i can recall, it taught that all individual and social ills were due to men's disregard of the laws of nature, which were classified as physical and moral. obey the laws of health and we and our posterity will all reach the age of one hundred years. obey the moral law and social evils will disappear. its reading was accompanied by some qualms of conscience, arising from the non-accordance of many of its tenets with those of the "catechism" and the "new england primer." the combination of the two, however, led to the optimistic feeling that all wrongs would be righted, every act of injustice punished, and truth and righteousness eventually triumph through the regular processes of nature and society. i have been led to abandon this doctrine only by much experience, some of which will be found in the following pages. in the direction of mathematical and physical science and reading generally, i may add something to what i have quoted from my father. my grandfather simon had a small collection of books in the family. among those purely literary were several volumes of "the spectator" and "roderick random." of the former i read a good deal. the latter was a story which a boy who had scarcely read any other would naturally follow with interest. two circumstances connected with the reading, one negative and the other positive, i recall. looking into the book after attaining years of maturity, i found it to contain many incidents of a character that would not be admitted into a modern work. yet i read it through without ever noticing or retaining any impression of the indelicate side of the story. the other impression was a feeling of horror that a man fighting a duel and finding himself, as he supposed, mortally wounded by his opponent, should occupy his mind with avenging his own death instead of making his peace with heaven. three mathematical books were in the collection, hammond's algebra, simpson's euclid, and moore's navigator, the latter the predecessor of bowditch. the first was a miserable book, and i think its methods, which were crude in the extreme, though not incorrect, were rather more harmful than beneficial. the queer diagrams in euclid had in my early years so little attraction for me that my curiosity never led me to examine its text. i at length did so in consequence of a passage in the algebra which referred to the 47th proposition of the first book. it occurred to me to look into the book and see what this was. it was the first conception of mathematical proof that i had ever met with. i saw that the demonstration referred to a previous proposition, went back to that, and so on to the beginning. a new world of thought seemed to be opened. that principles so profound should be reached by methods so simple was astonishing. i was so enraptured that i explained to my brother thomas while walking out of doors one day how the pythagorean proposition, as it is now called, could be proved from first principles, drawing the necessary diagrams with a pencil on a piece of wood. i thought that even cattle might understand geometry could they only be communicated with and made to pay attention to it. some one at school had a copy of mrs. marcet's "conversations on natural philosophy." with this book i was equally enraptured. meagre and even erroneous though it was, it presented in a pleasing manner the first principles of physical science. i used to steal into the schoolhouse after hours to read a copy of the book, which belonged to one of the scholars, and literally devoured it in a few evenings. my first undertaking in the way of scientific experiment was in the field of economics and psychology. when about fourteen i spent the winter in the house of an old farmer named jefferson. he and his wife were a very kindly couple and took much interest in me. he was fond of his pipe, as most old farmers are. i questioned whether anything else would not do just as well as tobacco to smoke, and whether he was not wasting his money by buying that article when a cheap substitute could be found. so one day i took his pipe, removed the remains of the tobacco ashes, and stuffed the pipe with tea leaves that had been steeped, and which in color and general appearance looked much like tobacco. i took care to be around when he should again smoke. he lit the pipe as usual and smoked it with, seemingly, as much satisfaction as ever, only essaying the remark, "this tobacco tastes like tea." my conscience pricked me, but i could say nothing. my father bought a copy of lardner's "popular lectures on science and art." in this i first read of electricity. i recall an incident growing out of it. in lardner's description of a leyden jar, water is the only internal conductor. the wonders of the newly invented telegraph were then explained to the people in out of the way places by traveling lecturers. one of these came to clements, where we then lived, with a lot of apparatus, amongst which was what i recognized as a leyden jar. it was coated with tin-foil on the outside, but i did not see the inner coating, or anything which could serve as the necessary conductor. so with great diffidence i asked the lecturer while he was arranging his things, if he was not going to put water into the jar. "no, my lad," was his reply, "i put lightning into it." i wondered how the "lightning" was going to be conveyed to the interior surface of the glass without any conductor, such as water, but was too much abashed to ask the question. moore's "navigator" taught not only a very crude sort of trigonometry, but a good deal about the warship of his time. to a boy living on the seacoast, who naturally thought a ship of war one of the greatest works of man, the book was of much interest. notwithstanding the intellectual pleasure which i have described, my boyhood was on the whole one of sadness. occasionally my love of books brought a word of commendation from some visitor, perhaps a methodist minister, who patted me on the head with a word of praise. otherwise it caused only exclamations of wonder which were distasteful. "you would n't believe what larnin' that boy has got. he has more larnin' than all the people around here put together," i heard one farmer say to another, looking at me, in my own view of the case, as if i were some monster misshapen in the womb. instead of feeling that my bookish taste was something to be valued, i looked upon myself as a _lusus naturæ_ whom nature had cruelly formed to suffer from an abnormal constitution, and lamented that somehow i never could be like other boys. the maladroitness described by my father, of which i was fully conscious, added to the feeling of my unfitness for the world around me. the skill required on a farm was above my reach, where efficiency in driving oxen was one of the most valued of accomplishments. i keenly felt my inability to acquire even respectable mediocrity in this branch of the agricultural profession. it was mortifying to watch the dexterous motions of the whip and listen to the torrent of imperatives with which a young farmer would set a team of these stolid animals in motion after they had failed to respond to my gentle requests, though conveyed in the best of ox language. i had indeed gradually formed, from reading, a vague conception of a different kind of world,--a world of light,--where dwelt men who wrote books and people who knew the men who wrote books,--where lived boys who went to college and devoted themselves to learning, instead of driving oxen. i longed much to get into this world, but no possibility of doing so presented itself. i had no idea that it would be imbued with sympathy for a boy outside of it who wanted to learn. true, i had once read in some story, perhaps fictitious, how a nobleman had found a boy reading newton's "principia," and not only expressed his pleased surprise at the performance, but actually got the boy educated. but there was no nobleman in sight of the backwoods of nova scotia. i read in the autobiography of franklin how he had made his way in life. but he was surrounded with opportunities from which i was cut off. it does seem a little singular that, well known as my tastes were to those around me, we never met a soul to say, "that boy ought to be educated." so far as i know, my father's idea of making me a lawyer met with nothing but ridicule from the neighbors. did not a lawyer have to know latin and have money to pursue his studies? in my own daydreams i was a farmer driving his own team; in my mother's a preacher, though she had regretfully to admit that i might never be good enough for this profession. [1] the actual sixth was my late excellent and esteemed cousin, judge simon bolivar newcomb, of new mexico. [2] he had evidently forgotten the home instruction from my aunts, received more than a year previous to the date he mentions. [3] the grandfather of president schurman of cornell university. i retain a dreamy impression of two half-grown or nearly grown boys, perhaps between fourteen and eighteen years of age, one of whom became, i believe, the father of the president. ii doctor foshay in the summer of 1851, when i had passed the age of sixteen, we lived in a little school district a mile or two from the town of yarmouth, n. s. late in the summer we had a visit from a maternal uncle and aunt. as i had not seen moncton since i was six years old, and as i wanted very much to visit my grandfather prince once more, it was arranged that i should accompany them on their return home. an additional reason for this was that my mother's health had quite failed; there was no prospect of my doing anything where i was, and it was hoped that something might turn up at moncton. there was but one difficulty; the visitors had driven to st. john in their own little carriage, which would hold only two people; so they could not take me back. i must therefore find my own way from st. john to moncton. we crossed the bay of fundy in a little sailing vessel. among the passengers was an english ship captain who had just been wrecked off the coast of newfoundland, and had the saved remnant of his crew with him. on the morning of our departure the weather was stormy, so that our vessel did not put to sea--a precaution for which the captain passenger expressed great contempt. he did not understand how a vessel should delay going to see on account of a little storm. the walk of one hundred miles from st. john to moncton was for me, at that time, a much less formidable undertaking than it would appear in our times and latitude. a thirty-mile tramp was a bagatelle, and houses of entertainment--farmhouses where a traveler could rest or eat for a few pennies--were scattered along the road. but there was one great difficulty at the start. my instructions had been to follow the telegraph wires. i soon found that the line of telegraph came into the town from one direction, passed through it, and then left, not in the opposite direction, but perhaps at right angles to it. in which direction was the line to be followed? it was difficult to make known what i wanted. "why, my boy, you can't walk to moncton," was one answer. in a shop the clerks thought i wanted to ride on the telegraph, and, with much chuckling, directed me to the telegraph office where the man in charge would send me on. i tried in one direction which i thought could not be right, then i started off in the opposite one; but it soon became evident that that branch led up the river to frederickton. so i had to retrace my steps and take the original line, which proved to be the right one. the very first night i found that my grandfather's name was one to conjure with. i passed it with a hearty old farmer who, on learning who i was, entertained me with tales of mr. prince. the quality which most impressed the host was his enormous physical strength. he was rather below the usual stature and, as i remember him, very slightly built. yet he could shoulder a barrel of flour and lift a hogshead of molasses on its end, feats of strength which only the most powerful men in the region were equal to. on reaching my destination, i was not many days in learning that my grandfather was a believer in the maxims of "poor richard's almanac," and disapproved of the aimless way in which i had been bred. he began to suggest the desirableness of my learning to do something to make a living. i thought of certain mechanical tastes which had moved me in former years to whittle and to make a reel on which to wind yarn, and to mend things generally. so i replied that i thought the trade of a carpenter was the one i could most easily learn. he approved of the idea, and expressed the intention of finding a carpenter who would want my services; but before he did so, i was started in a new and entirely different direction. on her last visit to her birthplace, my mother brought back glowing reports of a wonderful physician who lived near moncton and effected cures of the sick who had been given up by other doctors. i need hardly remark that physicians of wonderful proficiency--diomeds of the medical profession, before whose shafts all forms of disease had to fall--were then very generally supposed to be realities. the point which specially commended dr. foshay to us was that he practiced the botanic system of medicine, which threw mineral and all other poisons out of the materia medica and depended upon the healing powers of plants alone. people had seen so much of the evil effects of calomel, this being the favorite alternative of the profession, that they were quite ready to accept the new system. among the remarkable cures which had given dr. foshay his great reputation was one of a young man with dyspepsia. he was reduced to a shadow, and the regular doctors had given him up as incurable. the new doctor took him to his home. the patient was addicted to two practices, both of which had been condemned by his former medical advisers. one was that of eating fat pork, which he would do at any hour of the day or night. the new doctor allowed him to eat all he wanted. another was getting up in the night and practicing an ablution of the stomach by a method too heroic to be described in anything but a medical treatise. [1] he was now allowed to practice it to his heart's content. the outcome of the whole proceeding was that he was well in a few months, and, when i saw him, was as lusty a youth as one could desire to meet. before mr. prince could see a carpenter, he was taken ill. i was intensely interested to learn that his physician was the great doctor i had heard of, who lived in the village of salisbury, fifteen miles on the road to st. john. one of my aunts had an impression that the doctor wanted a pupil or assistant of some kind, and suggested that a possible opening might here be offered me. she promised to present me to the doctor on his next visit, after she had broached the subject to him. the time for which i waited impatiently at length arrived. never before had i met so charming a man. he was decidedly what we should now call magnetic. there was an intellectual flavor in his talk which was quite new to me. what fascinated me most of all was his speaking of the difficulties he encountered in supplying himself with sufficient "reading matter." he said it as if mental food was as much a necessity as his daily bread. he was evidently a denizen of that world of light which i had so long wished to see. he said that my aunt was quite right in her impression, and our interview terminated in the following liberal proposition on his part:-s. n. to live with the doctor, rendering him all the assistance in his power in preparing medicines, attending to business, and doing generally whatever might be required of him in the way of help. the doctor, on his part, to supply s. n.'s bodily needs in food and clothing, and teach him medical botany and the botanic system of medicine. the contract to terminate when the other party should attain the age of twenty-one. after mentioning the teaching clause, he corrected himself a moment, and added: "at least all i know about it." all he knows about it! what more could heart desire or brain hold? the brilliancy of the offer was dimmed by only a single consideration; i had never felt the slightest taste for studying medicine or caring for the sick. that my attainments in the line could ever equal those of my preceptor seemed a result too hopeless to expect. but, after all, something must be done, and this was better than being a carpenter. before entering upon the new arrangement, a ratification was required on both sides. the doctor had to make the necessary household arrangements, and secure the consent of his wife. i had to ask the approval of my father, which i did by letter. like general grant and many great men, he was a man of exceptional sagacity in matters outside the range of his daily concerns. he threw much cold water on the scheme, but consented to my accepting the arrangement temporarily, as there was nothing better to be done. i awaited the doctor's next visit with glowing anticipation. in due course of time i stepped with him into his gig for the long drive, expecting nothing less on the journey than a complete outline of the botanic system of medicine and a programme of my future studies. but scarcely had we started when a chilling process commenced. the man erstwhile so effusive was silent, cold, impassive,--a marble statue of his former self. i scarcely got three sentences out of him during the journey, and these were of the most commonplace kind. could it be the same man? there was something almost frightful in being alongside a man who knew so much. when we reached our destination the horse had to be put away in the stable. i jumped up to the haymow to throw down the provender. it was a very peculiar feeling to do so under the eye of a man who, as he watched me, knew every muscle that i was setting in operation. a new chill came on when we entered the house and i was presented to its mistress. "so you 're the boy that's come to work for the doctor, are you?" "i have come to study with him, ma'am"' was my interior reply, but i was too diffident to say it aloud. naturally the remark made me very uncomfortable. the doctor did not correct her, and evidently must have told her something different from what he told me. her tone was even more depressing than her words; it breathed a coldness, not to say harshness, to which i had not been accustomed in a woman. there was nothing in her appearance to lessen the unpleasant impression. small in stature, with florid complexion, wide cheek bones that gave her face a triangular form, she had the eye and look of a well-trained vixen. as if fate were determined to see how rapid my downfall should be before the close of the day, it continued to pursue me. i was left alone for a few minutes. a child some four years old entered and made a very critical inspection of my person. the result was clearly unfavorable, for she soon asked me to go away. finding me indisposed to obey the order, she proceeded to the use of force and tried to expel me with a few strong pushes. when i had had enough of this, i stepped aside as she was making a push. she fell to the floor, then picked herself up and ran off crying, "mamma." the latter soon appeared with added ire infused into her countenance. "what did you hit the child for?" "i did n't hit her. what should i want to strike a child like that for?" "but she says you hit her and knocked her down." "i did n't, though--she was trying to push me and fell and hurt herself." a long piercing look of doubt and incredulity followed. "strange, very strange. i never knew that child to tell a lie, and she says you struck her." it was a new experience--the first time i had ever known my word to be questioned. during the day one thought dominated all others: where are those treasures of literature which, rich though they are, fail to satisfy their owner's voracious intellectual appetite? as houses were then built, the living and sleeping rooms were all on one main floor. here they comprised a kitchen, dining room, medicine room, a little parlor, and two small sleeping rooms, one for the doctor and one for myself. before many hours i had managed to see the interior of every one except the doctor's bedroom, and there was not a sign of a book unless such common ones as a dictionary or a bible. what could it all mean? next day the darkness was illuminated, at least temporarily, by a ray of light. the doctor had been absent most of the day before on a visit to some distant patient. now he came to me and told me he wanted to show me how to make bilious powders. several trays of dried herbs had been drying under the kitchen stove until their leaves were quite brittle. he took these and i followed him to the narrow stairway, which we slowly ascended, he going ahead. as i mounted i looked for a solution of the difficulty. here upstairs must be where the doctor kept his books. at each step i peered eagerly ahead until my head was on a level with the floor. rafters and a window at the other end had successively come into view and now the whole interior was visible. nothing was there but a loft, at the further end of which was a bed for the housemaid. the floor was strewn with dried plants. nothing else was visible. the disillusion seemed complete. my heart sank within me. on one side of the stairway at a level with the floor was screwed a large coffee mill. the doctor spread a sheet of paper out on the floor on the other side, and laid a line sieve upon it. then he showed me how to grind the dry and brittle leaves in the coffee mill, put them into the sieve, and sift them on the paper. this work had a scientific and professional look which infused a glimmer of light into the cimmerian darkness. the bilious powders were made of the leaves of four plants familiarly known as spearmint, sunflower, smartweed, and yarrow. in his practice a heaping teaspoonful of the pulverized leaves was stirred in a cup of warm water and the grosser parts were allowed to settle, while the patient took the finer parts with the infusion. this was one of dr. foshay's staple remedies. another was a pill of which the principal active ingredient was aloes. the art of making these pills seemed yet more scientific than the other, and i was much pleased to find how soon i could master it. beside these a number of minor remedies were kept in the medicine room. among them were tinctures of lobelia, myrrh, and capsicum. there was also a pill box containing a substance which, from its narcotic odor, i correctly inferred to be opium. this drug being prohibited by the botanic school i could not but feel that dr. foshay's orthodoxy was painfully open to question. determined to fathom the mystery in which the doctor's plans for my improvement were involved, i announced my readiness to commence the study of the botanic system. he disappeared in the direction of his bedroom, and soon returned with--could my eyes believe it?--a big book. it was one which, at the time of its publication, some thirty or forty years before, was well known to the profession,--miner and tully on the "fevers of the connecticut valley." he explained bringing me this book. "before beginning the regular study of the botanic system, you must understand something of the old system. you can do so by reading this book." a duller book i never read. there was every sort of detail about different forms of fever, which needed different treatment; yet calomel and, i think, opium were its main prescriptions. in due time i got through it and reported to my preceptor. "well, what do you think of the book?" "it praises calomel and opium too much. but i infer from reading it that there are so many kinds of fever and other diseases that an immense amount of study will be required to distinguish and treat them." "oh, you will find that all these minute distinctions are not necessary when we treat the sick on the botanic system." "what is the next thing for me? can i not now go on with the study of the botanic system?" "you are not quite ready for it yet. you must first understand something about phrenology. one great difference between us and doctors of the old school is that they take no account of difference of temperament, but treat the lymphatic and bilious in the same way. but we treat according to the temperament of the patient and must therefore be expert in distinguishing temperaments." "but i studied phrenology long ago and think i understand it quite well." he was evidently surprised at this statement, but after a little consideration said it was very necessary to be expert in the subject, and thought i had better learn it more thoroughly. he returned to his bedroom and brought a copy of fowler's "phrenology," the very book so familiar to me. i had to go over it again, and did so very carefully, paying special attention to the study of the four temperaments,--nervous, bilious, lymphatic, and sanguine. before many days i again reported progress. the doctor seemed a little impatient, but asked me some questions about the position of the organs and other matters pertaining to the subject, which i answered promptly and correctly by putting my fingers on them on my own head. but though satisfied with the answers, it was easy to see that he was not satisfied with me. he had, on one or two previous occasions, intimated that i was not wise and prudent in worldly matters. now he expressed himself more plainly. "this world is all a humbug, and the biggest humbug is the best man. that 's the yankee doctrine, and that 's the reason the yankees get along so well. you have no organ of secretiveness. you have a window in your breast that every one can look into and see what you are thinking about. you must shut that window up, like i do. no one can tell from my talk or looks what i am thinking about." it may seem incredible to the reader that i marveled much at the hidden meaning of this allegorical speech, and never for one moment supposed it to mean: "i, dr. foshay, with my botanic system of medicine, am the biggest humbug in these parts, and if you are going to succeed with me you must be another." but i had already recognized the truth of his last sentence. probably neither of us had heard of talleyrand, but from this time i saw that his hearty laugh and lively talk were those of a manikin. his demeanor toward me now became one of complete gravity, formality, and silence. he was always kindly, but never said an unnecessary word, and avoided all reference to reading or study. the mystery which enveloped him became deeper month after month. in his presence i felt a certain awe which prevented my asking any questions as to his intentions toward me. it must, of course, be a matter of lifelong regret that two years so important in one's education should have been passed in such a way,--still, they were not wholly misspent. from a teacher named monroe, [2] who then lived near salisbury, i borrowed draper's chemistry, little thinking that i would one day count the author among my friends. a book peddler going his rounds offered a collection of miscellaneous books at auction. i bought, among others, a latin and a greek grammar, and assiduously commenced their study. with the first i was as successful as could be expected under the circumstances, but failed with the greek, owing to the unfamiliarity of the alphabet, which seemed to be an obstacle to memory of the words and forms. but perhaps the greatest event of my stay was the advent of a botanic druggist of boston, who passed through the region with a large wagonload of medicines and some books. he was a pleasant, elderly gentleman, and seemed much interested on learning that i was a student of the botanic system. he had a botanic medical college in or near boston, and strongly urged me to go thither as soon as i could get ready to complete my studies. from him the doctor, willing to do me a favor, bought some books, among them the "eclectic medical dispensary," published in cincinnati. of this book the doctor spoke approvingly, as founded on the true system which he himself practiced, and though i never saw him read it, he was very ready to accept the knowledge which i derived from it. the result was quite an enlargement of his materia medica, both in the direction of native plants and medicines purchased from his druggist. on one occasion this advance came near having serious consequences. i had compounded some pills containing a minute quantity of elaterium. the doctor gave them to a neighboring youth affected with a slight indisposition in which some such remedy was indicated. the directions were very explicit,--one pill every hour until the desired effect was produced. "pshaw," said the patient's brother, "there's nothin' but weeds in them pills, and a dozen of them won't hurt you." the idea of taking weed pills one at a time seemed too ridiculous, and so the whole number were swallowed at a dose. the result was, happily, not fatal, though impressive enough to greatly increase the respect of the young man's family for our medicines. the intellectual life was not wholly wanting in the village. a lodge of a temperance organization, having its headquarters in maine, was formed at a neighboring village. it was modeled somewhat after the fashion of the sons of temperance. the presiding officer, with a high sounding title, was my mother's cousin, tommy nixon. he was the most popular young man of the neighborhood. the rudiments of a classical education gained at a reputable academy in sackville had not detracted from his qualities as a healthy, rollicking young farmer. the lodge had an imposing ritual of which i well remember one feature. at stated intervals a password which admitted a member of any one lodge to a meeting of any other was received from the central authority--in maine, i believe. it was never to be pronounced except to secure admission, and was communicated to the members by being written on a piece of paper in letters so large that all could read. after being held up to view for a few moments, the paper was held in the flame of a candle with these words: "this paper containing our secret password i commit to the devouring element in token that it no longer exists save in the minds of the faithful brethren." the fine sonorous voice of the speaker and his manly front, seen in the lurid light of the burning paper, made the whole scene very impressive. there was also a society for the discussion of scientific questions, of which the founder and leading spirit was a youth named isaac steves, who was beginning the study of medicine. the president was a "worthy archon." our discussions strayed into the field of physiological mysteries, and got us into such bad odor with mrs. foshay and, perhaps, other ladies of the community, that the meetings were abandoned. a soil like that of the provinces at this time was fertile in odd characters including, possibly, here and there, a "heart pregnant with celestial fire." one case quite out of the common line was that of two or three brothers employed in a sawmill somewhere up the river petticodiac. according to common report they had invented a new language in order to enable them to talk together without their companions knowing what they were saying. i knew one of them well and, after some time, ventured to inquire about this supposed tongue. he was quite ready to explain it. the words were constructed out of english by the very simple process of reversing the syllables or the spelling. everything was pronounced backward. those who heard it, and knew the key, had no difficulty in construing the words; to those who did not, the words were quite foreign. the family of the neighborhood in which i was most intimate was that of a scotch farmer named parkin. father, mother, and children were very attractive, both socially and intellectually, and in later years i wondered whether any of them were still living. fifty years later i had one of the greatest and most agreeable surprises of my life in suddenly meeting the little boy of the family in the person of dr. george r. parkin, the well-known promoter of imperial federation in australia and the agent in arranging for the rhodes scholarships at oxford which are assigned to america. my duties were of the most varied character. i composed a little couplet designating my professions as those of physician, apothecary, chemist, and druggist, girl about house and boy in the barn. i cared for the horse, cut wood for the fire, searched field and forest for medicinal herbs, ordered other medicines from a druggist [3] in st. john, kept the doctor's accounts, made his pills, and mixed his powders. this left little time for reading and study, and such exercises were still farther limited by the necessity of pursuing them out of sight of the housewife. as time passed on, the consciousness that i was wasting my growing years increased. i long cherished a vague hope that the doctor could and would do something to promote my growth into a physician, especially by taking me out to see his patients. this was the recognized method of commencing the study of medicine. but he never proposed such a course to me, and never told me how he expected me to become a physician. every month showed my prospects in a less hopeful light. i had rushed into my position in blind confidence in the man, and without any appreciation of the requirements of a medical practitioner. but these requirements now presented themselves to my mind with constantly increasing force. foremost among them was a knowledge of anatomy, and how could that be acquired except at a medical school? it was every day more evident that if i continued in my position i should reach my majority without being trained for any life but that of a quack. while in this state of perplexity, an event happened which suggested a way out. one day the neighborhood was stirred by the news that tommy nixon had run away--left his home without the consent of his parents, and sailed for the gold fields of australia. i was struck by the absence of any word of reprobation for his act. the young men at least seemed to admire the enterprising spirit he had displayed. a few weeks after his departure a letter which he wrote from london, detailing his adventures in the great metropolis, was read in my presence to a circle of admiring friends with expressions of wonder and surprise. this little circumstance made it clear to me that the easiest way out of my difficulty was to out the gordian knot, run away from dr. foshay, and join my father in new england. no doubt the uppermost question in the mind of the reader will be: why did you wait so long without having a clear understanding with the doctor? why not ask him to his face how he expected you to remain with him when he had failed in his pledges, and demand that he should either keep them or let you go? one answer, perhaps the first, must be lack of moral courage to face him with such a demand. i have already spoken of the mystery which seemed to enshroud his personality, and of the fascination which, through it, he seemed to exercise over me. but behind this was the conviction that he could not do anything for me were he ever so well disposed. that he was himself uneducated in many essentials of his profession had gradually become plain enough; but what he knew or possibly might know remained a mystery. i had heard occasional allusions, perhaps from mrs. foshay rather than from himself, to an institution supposed to be in maine, where he had studied medicine, but its name and exact location were never mentioned. altogether, if i told him of my intention, it could not possibly do any good, and he might be able to prevent my carrying it out, or in some other way to do much harm. and so i kept silent. tuesday, september 13, 1853, was the day on which i fixed for the execution of my plan. the day previous i was so abstracted as to excite remarks both from mrs. foshay and her girl help, the latter more than once declaring me crazy when i made some queer blunder. the fact is i was oppressed by the feeling that the step about to be taken was the most momentous of my life. i packed a few books and clothes, including some mementoes of my mother, and took the box to the stage and post-office in the evening, to be forwarded to an assumed name in st. john the next afternoon. this box i never saw again; it was probably stopped by foshay before being dispatched. my plan was to start early in the morning, walk as far as i could during the day, and, in the evening, take the mail stage when it should overtake me. this course was necessitated by the fact that the little money that i had in my pocket was insufficient to pay my way to boston, even when traveling in the cheapest way. i thought it only right that the doctor should be made acquainted with my proceeding and my reason for taking it, so i indited a short letter, which i tried to reproduce from memory ten years later with the following result:- dear doctor,--i write this to let you know of the step i am about to take. when i came to live with you, it was agreed that you should make a physician of me. this agreement you have never shown the slightest intention of fulfilling since the first month i was with you. you have never taken me to see a patient, you have never given me any instruction or advice whatever. beside this, you must know that your wife treats me in a manner that is no longer bearable. i therefore consider the agreement annulled from your failure to fulfill your part of it, and i am going off to make my own way in the world. when you read this, i shall be far away, and it is not likely that we shall ever meet again. if my memory serves me right, the doctor was absent on a visit to some distant patient on the night in question, and i did not think it likely that he would return until at least noon on the following day. by this time my box would have been safely off in the stage, and i would be far out of reach. to delay his receiving the letter as much as possible, i did not leave it about the house, but put it in the window of a shop across the way, which served the neighbors as a little branch post-office. but he must have returned sooner than i expected, for, to my great regret, i never again saw or heard of the box, which contained, not only the entire outfit for my journey, but all the books of my childhood which i had, as well as the little mementoes of my mother. the postmaster who took charge of the goods was a mr. pitman. when i again passed through salisbury, as i did ten years later, he had moved away, no one could tell me exactly where. i was on the road before daybreak, and walked till late at night, occasionally stopping to bathe my feet in a brook, or to rest for a few minutes in the shadow of a tree. the possibility of my being pursued by the doctor was ever present to my mind, and led me to keep a sharp lookout for coming vehicles. toward sunset a horse and buggy appeared, coming over a hill, and very soon the resemblance of vehicle and driver to the turnout of the doctor became so striking that i concealed myself in the shrubbery by the wayside until the sound of the wheels told me he was well past. the probability that my pursuer was in front of me was an added source of discomfort which led me to avoid the road and walk in the woods wherever the former was not visible to some distance ahead. but i neither saw nor heard anything more of the supposed pursuer, though, from what i afterward learned, there can be little doubt that it was actually foshay himself. the advent of darkness soon relieved me of the threatened danger, but added new causes of solicitude. the evening advanced, and the lights in the windows of the houses were becoming fewer and fewer, and yet the stage had not appeared. i slackened my pace, and made many stops, beginning to doubt whether i might not as well give up the stage and look for an inn. it was, i think, after ten o'clock when the rattling of wheels announced its approach. it was on a descending grade, and passed me like a meteor, in the darkness, quite heedless of my calls and gesticulations. fortunately a house was in sight where i was hospitably entertained, and i was very soon sound asleep, as became one who had walked fifty miles or more since daylight. thus ended a day to which i have always looked back as the most memorable of my life. i felt its importance at the time. as i walked and walked, the question in my mind was, what am i doing and whither am i going? am i doing right or wrong? am i going forward to success in life, or to failure and degradation? vainly, vainly, i tried to peer into the thick darkness of the future. no definite idea of what success might mean could find a place in my mind. i had sometimes indulged in daydreams, but these come not to a mind occupied as mine on that day. and if they had, and if fancy had been allowed its wildest flight in portraying a future, it is safe to say that the figure of an honorary academician of france, seated in the chair of newton and franklin in the palace of the institute, would not have been found in the picture. as years passed away i have formed the habit of looking back upon that former self as upon another person, the remembrance of whose emotions has been a solace in adversity and added zest to the enjoyment of prosperity. if depressed by trial, i think how light would this have appeared to that boy had a sight of the future been opened up to him. when, in the halls of learning, i have gone through the ceremonies which made me a citizen of yet another commonwealth in the world of letters, my thoughts have gone back to that day; and i have wished that the inexorable law of nature could then have been suspended, if only for one moment, to show the scene that providence held in reserve. next morning i was on my way betimes, having still more than thirty miles before me. and the miles seemed much longer than they did the day before, for my feet were sore and my limbs stiff. quite welcome, therefore, was a lift offered by a young farmer, who, driving a cart, overtook me early in the forenoon. he was very sociable, and we soon got into an interesting conversation. i knew that dr. foshay hailed from somewhere in this region, where his father still lived, so i asked my companion whether he knew a family of that name. he knew them quite well. "do you know anything of one of the sons who is a doctor?" "yes indeed; i know all about him, but he ain't no doctor. he tried to set up for one in salisbury, but the people there must a' found him out before this, and i don't know where he is now." "but i thought he studied medicine in fredericton or maine or somewhere on the border." "oh, he went off to the states and pretended to study, but he never did it. i tell you he ain't no more a doctor nor i am. he ain't smart enough to be a doctor." i fell into a fit of musing long enough to hear, in my mind's ear, with startling distinctness, the words of two years before: "this world is all a humbug, and the biggest humbug is the best man. . . . you have a window in your breast and you must close that window before you can succeed in life." now i grasped their full meaning. ten years later i went through the province by rail on my wedding journey. at dorchester, the next village beyond moncton, i was shown a place where insolvent debtors were kept "on the limits." "by stopping there," said my informant, "you can see dr. foshay." i suggested the question whether it was worth while to break our journey for the sake of seeing him. the reply of my informant deterred me. "it can hardly be worth while to do so. he will be a painful object to see,--a bloated sot, drinking himself to death as fast as he can." the next i heard of him was that he had succeeded. i reached st. john on the evening that a great celebration of the commencement of work on the first railway in the province was in progress. when things are undecided, small matters turn the scale. the choice of my day for starting out on my adventurous journey was partly fixed by the desire to reach st. john and see something of the celebration. darkness came on when i was yet a mile or two from the city; then the first rocket i had ever beheld rose before me in the sky. two of what seemed like unfortunate incidents at the time were most fortunate. subsequent and disappointing experience showed that had i succeeded in getting the ride i wished in the stage, the resulting depletion of my purse would have been almost fatal to my reaching my journey's end. arriving at the city, i naturally found all the hotels filled. at length a kindly landlady said that, although she had no bed to give me, i was quite welcome to lie on a soft carpeted floor, in the midst of people who could not find any other sleeping place. no charge was made for this accommodation. my hope of finding something to do which would enable me to earn a little money in st. john over and above the cost of a bed and a daily loaf of bread was disappointed. the efforts of the next week are so painful to recall that i will not harrow the feelings of the reader by describing them. suffice it to say that the adventure was wound up by an interview at calais, a town on the maine border, a few miles from eastport, with the captain of a small sailing vessel, hardly more than a boat. he was bound for salem. i asked him the price of a passage. "how much money have you?" he replied. i told him; whether it was one or two dollars i do not recall. "i will take you for that if you will help us on the voyage." the offer was gladly accepted. the little craft was about as near the opposite of a clipper ship as one can imagine, never intended to run in any but fair winds, and even with that her progress was very slow. there was a constant succession of west winds, and the result was that we were about three weeks reaching salem. here i met my father, who, after the death of my mother, had come to seek his fortune in the "states." he had reached the conclusion, on what grounds i do not know, that the eastern part of maryland was a most desirable region, both in the character of its people and in the advantages which it offered us. the result was that, at the beginning of 1854, i found myself teacher of a country school at a place called massey's cross roads in kent county. after teaching here one year, i got a somewhat better school at the pleasant little village of sudlersville, a few miles away. of my abilities as a manager and teacher of youth the reader can judge. suffice it to say that, looking back at those two years, i am deeply impressed with the good nature of the people in tolerating me at all. my most pleasant recollection is that of two of my best pupils of sudlersville, nearly my own age. one was arthur e. sudler, for whose special benefit some chemical apparatus was obtained from philadelphia. he afterwards studied medicine at the university of pennsylvania and delighted me by writing that what i had taught him placed him among the best in his class in chemistry. the other was b. s. elliott, who afterward became an engineer or surveyor. one of my most vivid recollections at massey's relates to a subject which by no means forms a part of one's intellectual development, and yet is at the bottom of all human progress, that of digestion. the staple food of the inhabitants of a southern farming region was much heartier than any to which i had been accustomed. "pork and pone" were the staples, the latter being a rather coarse cake with little or no seasoning, baked from cornmeal. this was varied by a compound called "shortcake," a mixture of flour and lard, rapidly baked in a pan, and eaten hot. though not distasteful, i thought it as villainous a compound as a civilized man would put into his stomach. quite near my school lived a young bachelor farmer who might be designated as william bowler, esq., though he was better known as billy bowler. he had been educated partly at delaware college, newark, and was therefore an interesting young man to know. in describing his experiences at the college, he once informed me that they were all very pleasant except in a single point; that was the miserably poor food that the students got to eat. he could not, he declared, get along without good eating. this naturally suggested that my friend was something of a gourmand. great, therefore, was my delight when, a few weeks later, he expressed a desire to have me board with him. i accepted the offer as soon as possible. much to my disappointment, shortcake was on the table at the first meal and again at the second. it proved to be the principal dish twice, and i am not sure but three times a day. the other staple was fried meat. on the whole this was worse than pork and pone, which, if not toothsome, was at least wholesome. as the days grew into weeks, i wondered what delaware college could give its students to eat. to increase the perplexity, there were plenty of chickens in the yard and vegetables in the garden. i asked the cook if she could not boil some vegetables and bring them on the table. "mas'er bowler don't like wegetable." then i found that the chickens were being consumed in the kitchen and asked for one. "mas'er bowler don't like chicken," was the reply, with an added intimation that the chickens belonged to the denizens of the kitchen. the mystery was now so dark and deep that i determined to fathom it. i drew mr. bowler into conversation once more about delaware college, and asked him what the students had to eat when there. he had evidently forgotten his former remark and described what seemed to me a fairly well provided students' table. now i came down on him with my crusher. "you told me once that the table was miserably poor, so that you could hardly stand it. what fault had you to find with it?" he reflected a moment, apparently recalling his impression, then replied: "oh, they had no shortcake there!" in 1854 i availed myself of my summer vacation to pay my first visit to the national capital, little dreaming that it would ever be my home. i went as far as the gate of the observatory, and looked wistfully in, but feared to enter, as i did not know what the rules might be regarding visitors. i speculated upon the possible object of a queer red sandstone building, which seemed so different from anything else, and heard for the first time of the smithsonian institution. on the very beginning of my work at massey's the improvement in my position was so remarkable that i felt my rash step of a few months before fully justified. i wrote in triumph to my favorite aunt, rebecca prince, that leaving dr. foshay was the best thing i had ever done. i was no longer "that boy," but a respectable young man with a handle to my name. just what object i should pursue in life was still doubtful; the avenues of the preferment i would have liked seemed to be closed through my not being a college graduate. i had no one to advise me as to the subjects i should pursue or the books i should study. on such books as i could get, i passed every spare hour. my father sent me cobbett's english grammar, which i found amusing and interesting, especially the criticisms upon the grammar found here and there in royal addresses to parliament and other state papers. on the whole i am not sure but that the book justified my father's good opinion, although i cannot but think that it was rather hypercritical. i had been taught the rudiments of french in wallace when quite a child by a mr. oldright, of whose methods and pronunciation my memory gives me a most favorable impression. i now got cobbett's french grammar, probably a much less commendable book than his english one. i had never yet fathomed the mysteries of analytic geometry or the calculus, and so got davies' books on those subjects. that on the calculus was perhaps the worst that could be put into the hands of a person situated as i was. two volumes of bezout's mathematics, in french, about a century old, were, i think, rather better. say's political economy was the first book i read on that subject, and it was quite a delight to see human affairs treated by scientific methods. i finally reached the conclusion that mathematics was the study i was best fitted to follow, though i did not clearly see in what way i should turn the subject to account. i knew that newton's "principia" was a celebrated book, so i got a copy of the english translation. the path through it was rather thorny, but i at least caught the spirit here and there. no teacher at the present time would think of using it as a text-book, yet as a mental discipline, and for the purpose of enabling one to form a mental image of the subject, its methods at least are excellent. i got a copy of the "american journal of science," hoping it might enlighten me, but was frightened by its big words, and found nothing that i could understand. during the year at sudlersville i made several efforts which, though they were insignificant so far as immediate results were concerned, were in some respects of importance for my future work. with no knowledge of algebra except what was derived from the meagre text-books i could pick up,--not having heard even the name of abel, or knowing what view of the subject was taken by professional mathematicians,--i made my first attempt at a scientific article, "a new demonstration of the binomial theorem." this i sent to professor henry, secretary of the smithsonian institution, to see if he deemed it suitable for publication. he promptly replied in the negative, but offered to submit it to a professional mathematician for an opinion of its merits. i gladly accepted this proposal, which was just what i wanted. in due course a copy of the report was sent me. one part of the work was praised for its elegance, but a lack of completeness and rigor was pointed out. it was accompanied by a pleasant note from professor henry remarking that, while not so favorable as i might have expected, it was sufficiently so to encourage me in persevering. the other effort to which i refer was of quite a different character. a copy of the "national intelligencer," intended for some subscriber who had left sudlersville, came to the post-office for several months, and, there being no claimant, i frequently had an opportunity to read it. one of its features was frequent letters from volunteer writers on scientific subjects. among these was a long letter from one g. w. eveleth, the object of which was to refute the accepted theory of the universe, especially the view of copernicus. for aught i knew mr. eveleth held as high a position as any one else in the world of science and letters, so i read his article carefully. it was evidently wholly fallacious, yet so plausible that i feared the belief of the world in the doctrine of copernicus might suffer a severe shock, and hastened to the rescue by writing a letter over my own name, pointing out the fallacies. this was published in the "national intelligencer"--if my memory serves me right--in 1855. my full name, printed in large capitals, in a newspaper, at the bottom of a letter, filled me with a sense of my temerity in appearing so prominently in print, as if i were intruding into company where i might not be wanted. my letter had two most unexpected and gratifying results. one was a presentation of a copy of lee's "tables and formulæ," which came to me a few days later through the mail with the compliments of colonel abert. not long afterward came a letter from professor j. lawrence smith, afterward a member of the national academy of sciences, transmitting a copy of a pamphlet by him on the theory that meteorites were masses thrown up from the volcanoes of the moon, and asking my opinion on the subject. i had not yet gotten into the world of light. but i felt as one who, standing outside, could knock against the wall and hear an answering knock from within. the beginning of 1856 found me teaching in the family of a planter named bryan, residing in prince george county, md., some fifteen or twenty miles from washington. this opened up new opportunities. i could ride into washington whenever i wished, leave my horse at a livery stable, and see whatever sights the city offered. the smithsonian library was one of the greatest attractions. sometime in may, 1856, i got permission from the attendant in charge to climb into the gallery and see the mathematical books. here i was delighted to find the greatest treasure that my imagination had ever pictured,--a work that i had thought of almost as belonging to fairyland. and here it was right before my eyes--four enormous volumes,--"mécanique céleste, by the marquis de laplace, peer of france; translated by nathaniel bowditch, ll. d., member of the royal societies of london, edinburg, and dublin." i inquired as to the possibility of my borrowing the first volume, and was told that this could be done only by special authority of professor henry. i soon got the necessary authority through mr. rhees, the chief clerk, whose kindness in the matter deeply impressed me, signed a promise to return it within one month, and carried it in triumph to my little schoolhouse. i dipped into it here and there, but at every step was met by formulæ and methods quite beyond the power of one who knew so little of mathematics. in due time i brought the book back as promised. up to this time i think i had never looked upon a real live professor; certainly not upon one of eminence in the scientific world. i wondered whether there was any possibility of my making the acquaintance of so great a man as professor henry. some time previous a little incident had occurred which caused me some uneasiness on the subject. i had started out very early on a visit to washington, or possibly i had stayed there all night. at any rate, i reached the smithsonian building quite early, opened the main door, stepped cautiously into the vestibule, and looked around. here i was met by a short, stout, and exceedingly gruff sort of a man, who looked upon my entrance with evident displeasure. he said scarcely a word, but motioned me out of the door, and showed me a paper or something in the entrance which intimated that the institution would be open at nine o'clock. it was some three minutes before that hour so i was an intruder. the man looked so respectable and so commanding in his appearance that i wondered if he could be professor henry, yet sincerely hoped he was not. i afterward found that he was only "old peake," the janitor. [4] when i found the real professor henry he received me with characteristic urbanity, told me something of his own studies, and suggested that i might find something to do in the coast survey, but took no further steps at that time. the question whether i was fitted for any such employment now became of great interest. the principal question was whether one must know celestial mechanics in order to secure such a position, so, after leaving professor henry, i made my way to the coast survey office, and was shown to the chief clerk, as the authority for the information. i modestly asked him whether a knowledge of physical astronomy was necessary to a position in that office. instead of frankly telling me that he did not know what physical astronomy was, he answered in the affirmative. so i left with the impression that i must master the "mécanique céleste" or some similar treatise before finding any opening there. i could not, of course, be satisfied with a single visit to such a man, and so called several times during the year. one thing i wondered about was whether he would remember me when he again saw me. on one occasion i presented him with a plan for improving the cavendish method of determining the density of the earth, which he took very kindly. i subsequently learned that he was much interested in this problem. on another occasion he gave me a letter to mr. j. e. hilgard, assistant in charge of the coast survey office. my reception by the latter was as delightful as that by professor henry. i found from my first interview with him that the denizens of the world of light were up to the most sanguine conceptions i ever could have formed. at this time, or probably some time before, i bought a copy of the "american ephemeris" for 1858, and amused myself by computing on a slate the occultations visible at san francisco during the first few months of the year. at this time i had learned nothing definite from mr. hilgard as to employment in his office. but about december, 1856, i received a note from him stating that he had been talking about me to professor winlock, superintendent of the "nautical almanac," and that i might possibly get employment on that work. when i saw him again i told him that i had not yet acquired such a knowledge of physical astronomy as would be necessary for the calculations in question; but he assured me that this was no drawback, as formulæ for all the computations would be supplied me. i was far from satisfied at the prospect of doing nothing more than making routine calculations with formulæ prepared by others; indeed, it was almost a disappointment to find that i was considered qualified for such a place. i could only console myself by the reflection that the ease of the work would not hinder me from working my way up. shortly afterward i understood that it was at least worth while to present myself at cambridge, and so started out on a journey thither about the last day of the year 1856. at that time even a railroad journey was quite different from what it is now. the cars were drawn through baltimore by horses. at havre de grace the train had to stop and the passengers were taken across the river in a ferryboat to another train. at philadelphia the city had to be traversed by transfer coaches. looking around for this conveyance, i met a man who said he had it. he shoved me into it and drove off. i remarked with suspicion that no other coaches were accompanying us. after a pretty long drive the speed of the horses gradually began to slacken. at length it came to a complete stop in front of a large building, and i got out. but it was only a freight station, locked up and dark throughout. the driver mumbled something about his fare, then rolled back on his seat, seemingly dead drunk. the nearest sign of life was at a tavern a block or two away. there i found that i was only a short distance from the station of departure, and reached my train barely in time. landing in new york at the first glimmer of dawn, near the end of the line of passengers i was momentarily alarmed to see a man pick up what seemed to be a leather purse from right between my feet. it was brown and, so far as i could see, just like my own. i immediately felt the breast pocket of my coat and found that my own was quite safe. the man who picked up the purse inquired in the politest tone possible if it was mine, to which i replied in the negative. he retreated a short distance and then a bystander came up and chided me in a whisper for my folly in not claiming the purse. the only reply he got was, "oh, i'm up to all your tricks." on a repetition of this assurance the pair sneaked away. arriving at cambridge, i sought out professor winlock and was informed that no immediate employment was open at his office. it would be necessary for him to get authority from washington. after this was obtained some hope might be held out, so i appeared in the office from time to time as a visitor, my first visit being that described in the opening chapter. [1] i may remark, for the benefit of any medical reader, that it involved the use of two pails, one full of water, the other empty. when he got through the ablution, one pail was empty, and the other full. my authority for the actuality of this remarkable proceeding was some inmate of the house at the time, and i give credence to the story because it was not one likely to be invented. [2] rev. alexander h. monroe, who, i have understood, afterward lived in montreal. i have often wished to find a trace of him, but do not know whether he is still living. [3] our druggist was mr. s. l. tilley, afterward sir leonard tilley, the well-known canadian minister of finance. [4] peake, notwithstanding his official title, would seem to have been more than an ordinary janitor, as he was the author of a guide to the smithsonian institution. iii the world of sweetness and light the term "nautical almanac" is an unfortunate misnomer for what is, properly speaking, the "astronomical ephemeris." it is quite a large volume, from which the world draws all its knowledge of times and seasons, the motions of the heavenly bodies, the past and future positions of the stars and planets, eclipses, and celestial phenomena generally which admit of prediction. it is the basis on which the family almanac is to rest. it also contains the special data needed to enable the astronomer and navigator to determine their position on land or sea. the first british publication of the sort, prepared by maskelyne, astronomer royal, a century ago, was intended especially for the use of navigators; hence the familiar appellation, which i call unfortunate because it leads to the impression that the work is simply an enlargement and improvement of the household almanac. the leading nations publish ephemerides of this sort. the introductions and explanations are, of course, in the languages of the respective countries; but the contents of the volume are now so much alike that the duplication of work involved in preparing them seems quite unnecessary. yet national pride and emulation will probably continue it for some time to come. the first appropriation for an american ephemeris and nautical almanac was made by congress in 1849. lieutenant charles henry davis, as a leader and moving spirit in securing the appropriation, was naturally made the first superintendent of the work. at that time astronomical science in our country was so far from being reduced to a system that it seemed necessary to have the work prepared at some seat of learning. so, instead of founding the office in washington, it was established at cambridge, the seat of harvard university, where it could have the benefit of the technical knowledge of experts, and especially of professor benjamin peirce, who was recognized as the leading mathematician of america. here it remained until 1866, when conditions had so far changed that the office was removed to washington, where it has since remained. to this work i was especially attracted because its preparation seemed to me to embody the highest intellectual power to which man had ever attained. the matter used to present itself to my mind somewhat in this way: supply any man with the fundamental data of astronomy, the times at which stars and planets cross the meridian of a place, and other matters of this kind. he is informed that each of these bodies whose observations he is to use is attracted by all the others with a force which varies as the inverse square of their distance apart. from these data he is to weigh the bodies, predict their motion in all future time, compute their orbits, determine what changes of form and position these orbits will undergo through thousands of ages, and make maps showing exactly over what cities and towns on the surface of the earth an eclipse of the sun will pass fifty years hence, or over what regions it did pass thousands of years ago. a more hopeless problem than this could not be presented to the ordinary human intellect. there are tens of thousands of men who could be successful in all the ordinary walks of life, hundreds who could wield empires, thousands who could gain wealth, for one who could take up this astronomical problem with any hope of success. the men who have done it are therefore in intellect the select few of the human race,--an aristocracy ranking above all others in the scale of being. the astronomical ephemeris is the last practical outcome of their productive genius. on the question whether the world generally reasoned in this way, i do not remember having any distinct idea. this was certainly not because i was indifferent to the question, but because it never strongly presented itself to my mind. from my point of view it would not have been an important one, because i had already formed the conviction that one should choose that sphere in life to which he was most strongly attracted, or for which his faculties best fitted him. a few months previous to my advent commander davis had been detached from the superintendency and ordered to command the sloop st. mary's. he was succeeded by professor joseph winlock, who afterward succeeded george p. bond as director of the harvard observatory. most companionable in the society of his friends, winlock was as silent as general grant with the ordinary run of men. withal, he had a way of putting his words into exact official form. the following anecdote of him used to be current. while he was attached to the naval academy, he was introduced one evening at a reception to a visiting lady. he looked at the lady for a decorous length of time, and she looked at him; then they parted without saying a word. his introducer watched the scene, and asked him, "why did you not talk to that lady?" "i had no statement to make to her," was the reply. dr. gould told me this story was founded on fact, but when, after winlock's death, it was put off on me with some alterations, i felt less sure. the following i believe to be authentic. it occurred several years later. hilgard, in charge of the coast survey office, was struck by the official terseness of the communications he occasionally received from winlock, and resolved to be his rival. they were expecting additions to their families about the same time, and had doubtless spoken of the subject. when hilgard's arrived, he addressed a communication to winlock in these terms:-"mine's a boy. what's yours?" in due course of time the following letter was received in reply:-dear hilgard:- _boy._ yours, etc., j. winlock. when some time afterward i spoke to winlock on the subject, and told him what hilgard's motive was, he replied, "it was not fair in hilgard to try and take me unawares in that way. had i known what he was driving at, i might have made my letter still shorter." i did not ask him how he would have done it. it is of interest that the "boy" afterward became one of the assistant secretaries of the smithsonian institution. one of the most remarkable features of the history of the "nautical almanac" is the number of its early assistants who have gained prominence or distinction in the various walks of life. it would be difficult to find so modest a public work to exceed it in this respect. john d. runkle, who lived till 1902, was, as i have said, the senior and leading assistant in the office. he afterward became a professor in the institute of technology, and succeeded rogers as its president. in 1876 he started the school of manual training, which has since been one of the great features of the institute. he afterward resigned the presidency, but remained its principal professor of mathematics. he was the editor and founder of the "mathematical monthly," of which i shall presently have more to say. the most wonderful genius in the office, and the one who would have been the most interesting subject of study to a psychologist, was truman henry safford. in early childhood he had excited attention by his precocity as what is now sometimes called a "lightning calculator." a committee of the american academy of arts and science was appointed to examine him. it very justly and wisely reported that his arithmetical powers were not in themselves equal to those of some others on record, especially zerah colburn, but that they seemed to be the outcome of a remarkable development of the reasoning power. when nine years old, he computed almanacs, and some of his work at this age is still preserved in the harvard university library. he graduated at harvard in 1854, and was soon afterward taken into the nautical almanac office, while he also worked from time to time at the cambridge observatory. it was found, however, that the power of continuous work was no greater in him than in others, nor did he succeed in doing more than others in the course of a year. the mental process by which certain gifted arithmetical computers reach almost in an instant the results of the most complicated calculations is a psychological problem of great interest, which has never been investigated. no more promising subject for the investigation could ever have been found than safford, and i greatly regret having lost all opportunities to solve the problem. what was of interest in safford's case was the connection of this faculty with other remarkable mental powers of an analogous but yet different kind. he had a remarkable faculty for acquiring, using, and reading languages, and would have been an accomplished linguist had he turned his attention in that direction. he was a walking bibliography of astronomy, which one had only to consult in order to learn in a moment what great astronomers of recent times had written on almost any subject, where their work was published, and on what shelf of the harvard library the book could be found. but the faculty most closely connected with calculation was a quickness and apprehension of vision, of which the following is an example:-about 1876 he visited the naval observatory in washington for the first time in his life. we wanted a certain catalogue of stars and went together into the library. the required catalogue was on one of a tier of shelves containing altogether a hundred, or perhaps several hundred volumes. "i do not know whether we have the book," said i, "but if we have, it is on one of these shelves." i began to go through the slow process of glancing at the books one by one until my eyes should strike the right title. he stood back six or eight feet and took in all the shelves seemingly at one glance, then stepped forward and said, "here it is." i might have supposed this an accident, but that he subsequently did practically the same thing in my office, selecting in a moment a book we wanted to see, after throwing a rapid glance over shelves containing perhaps a hundred volumes. an example of his apprehension and memory for numbers was narrated by mr. alvan clark. when the latter had completed one of his great telescopes for the university of chicago, safford had been named as director, and accompanied the three members of the firm to the city when they carried the object glass thither. on leaving the train all four took their seats in a hotel omnibus, safford near the door. then they found that they had forgotten to give their baggage checks to the expressman; so the other three men passed their checks to safford, who added his own and handed all four to the conductor of the omnibus. when it was time for the baggage to come to the hotel, there was such a crowd of new arrivals that the attendants could not find it. the hotel clerk remarked on inquiry, "if i only knew the numbers of your checks, i would have no difficulty in tracing your trunks." safford at once told off the four numbers, which he had read as he was passing the checks to the conductor. the great fire practically put an end to the activity of the chicago observatory and forced its director to pursue his work in other fields. that he failed to attain that commanding position due to his genius is to be ascribed to a cause prevalent among us during all the middle part of the century; perhaps that from which most brilliant intellects fail to reach eminence: lack of the power of continuous work necessary to bring important researches to a completion. another great intellect of the office was chauncey wright. if wright had systematically applied his powers, he might have preceded or supplanted herbert spencer as the great exponent of the theory of evolution. he had graduated at harvard in 1853, and was a profound student of philosophy from that time forward, though i am not aware that he was a writer. when in 1858 sir william hamilton's "lectures on metaphysics" appeared, he took to them with avidity. in 1859 appeared darwin's "origin of species," and a series of meetings was held by the american academy, the special order of which was the discussion of this book. wright and myself, not yet members, were invited to be present. to judge of the interest it is only necessary to remark that agassiz and gray were the two leading disputants, the first taking ground against darwin, the other in his favor. wright was a darwinist from the very beginning, explaining the theory in private conversation from a master's point of view, and soon writing upon it in the "north american review" and in other publications. of one of his articles darwin has been quoted as saying that it was the best exposition of his theory that had then appeared. after his untimely death in 1875, wright's papers were collected and published under the title of "philosophical discussions." [1] their style is clear-cut and faultless in logical form, yet requiring such close attention to every word as to be less attractive to the general reader of to-day than that of spencer. in a more leisurely age, when men wanted to think profoundly as they went along in a book, and had little to disturb the current of their thoughts, it would have commanded wide attention among thinking men. a singular peculiarity which i have sometimes noticed among men of intelligence is that those who are best informed on the subject may be most reckless as regards the laws of health. wright did all of his office work in two or three months of the year. during those months he worked at his computations far into the hours of the morning, stimulating his strength with cigars, and dropping his work only to take it up when he had had the necessary sleep. a strong constitution might stand this for a few years, as his did. but the ultimate result hardly needs to be told. besides the volume i have mentioned, wright's letters were collected and printed after his death by the subscription of his friends. in these his philosophic views are from time to time brought out in a light, easy way, much more charming than the style of his elaborate discussions. it was in one of his letters that i first found the apothegm, "men are born either platonists or aristotelians," a happy drawing of the line which separates the hard-headed scientific thinker of to-day from the thinkers of all other classes. william ferrell, a much older man than myself, entered the office about the same time as i did. he published papers on the motions of fluids on the earth's surface in the "mathematical monthly," and became one of the great authorities on dynamic meteorology, including the mathematical theory of winds and tides. he was, i believe, the first to publish a correct theory of the retardation produced in the rotation of the earth by the action of the tides, and the consequent slow lengthening of the day. james edward oliver might have been one of the great mathematicians of his time had he not been absolutely wanting in the power of continuous work. it was scarcely possible to get even his year's office work out of him. yet when i once wrote him a question on certain mathematical forms which arise in the theory of "least squares," he replied in a letter which, with some developments and change of form, would have made a worthy memoir in any mathematical journal. as a matter of fact, the same thoughts did appear some years after, in an elaborate paper by professor j. w. l. glaisher, of england, published by the royal astronomical society. oliver, who afterward became professor of higher mathematics at cornell university, was noted for what i think should be considered the valuable quality of absent-mindedness. it was said of him that he was once walking on the seashore with a small but valuable gold watch loose in his pocket. while deep in thought he started a kind of distraction by picking up flat stones and skipping them on the water. taking his watch from his pocket he skipped it as a stone. when i became well acquainted with him i took the liberty of asking him as to the correctness of this story. he could not positively say whether it was true or not. the facts were simply that he had the watch, that he had walked on the seashore, had skipped stones, missed the watch at some subsequent time, and never saw it again. more definite was an observation made on his movements one afternoon by a looker-out from a window of the nautical almanac office. across the way the road was bounded by no fence, simply passing along the side of an open field. as oliver got near the office, his chin on his breast, deep in thought, he was seen gradually to deviate from the sidewalk, and direct his steps along the field. he continued on this erratic course until he ran almost against the fence at the other end. this awoke him from his reverie, and he started up, looked around, and made his way back to the road. i have spoken only of the men who were employed at the office at the time i entered. previous to my time were several who left to accept professorships in various parts of the country. among them were professors van vleck, of middletown, and hedrick and kerr, of north carolina. not desiring to leave upon the mind of the reader the impression that all of whom i have not spoken remained in obscurity, i will remark that mr. isaac bradford rose to the position of mayor of the city of cambridge, and that fugitive pieces in prose and poetry by mr. e. j. loomis were collected in a volume. [2] the discipline of the public service was less rigid in the office at that time than at any government institution i ever heard of. in theory there was an understanding that each assistant was "expected" to be in the office five hours a day. the hours might be selected by himself, and they generally extended from nine until two, the latter being at that time the college and family dinner hour. as a matter of fact, however, the work was done pretty much where and when the assistant chose, all that was really necessary being to have it done on time. it will be seen that the excellent opportunities offered by this system were well improved by those who enjoyed them--improved in a way that i fear would not be possible in any other surroundings. i took advantage of them by enrolling myself as a student of mathematics in the lawrence scientific school. on this occasion i well remember my pleasant reception by charles w. eliot, tutor in mathematics, and e. n. horsford, professor of chemistry, and, i believe, dean of the school. as a newcomer into the world of light, it was pleasant to feel the spirit with which they welcomed me. the departments of chemistry and engineering were about the only ones which, at that time, had any distinct organization. as a student of mathematics it could hardly be said that anything was required of me either in the way of attendance on lectures or examinations until i came up for the degree of bachelor of science. i was supposed, however, to pursue my studies under the direction of professor peirce. so slight a connection with the university does not warrant me in assuming an authoritative position as an observer of its men or its workings. yet there are many features associated with it which i have not seen in print, which have probably disappeared with the progress of the age, and to which, therefore, allusion may be made. one, as it presents itself to my memory, is the great variety and picturesqueness of character which the university then presented. i would like to know whether the changes in men which one fancies he sees during his passage from youth to age are real, or only relative to his point of view. if my impressions are correct, our educational planing mill cuts down all the knots of genius, and reduces the best of the men who go through it to much the same standard. does not the harvard professor of to-day always dine in a dress coat? is he not free from every eccentricity? do the students ever call him "benny" or "tobie"? is any "old soph" [3] now ambulant on the college green? is not the administration of the library a combination of liberality and correctness? is such a librarian as john langdon sibley possible? mr. sibley, under a rough exterior, was one of the best-hearted and most admirable of men, with whom i ultimately formed an intimate friendship. but our first acquaintance was of a very unfavorable kind. it came about in this way: not many days after being taken into the nautical almanac office i wanted a book from the university library, and asked a not over-bright old gentleman in the office what formalities were necessary in order to borrow it. "just go over and tell them you want it for the nautical almanac." "but they don't know me at the library, and surely will not give a book to any stray caller because he says he wants it for the nautical almanac." "you have only to say 'nautical almanac' and you will get the book." i argued the matter as stoutly as courtesy admitted, but at length, concluding that i was new to the rules and regulations of the place, accepted the supposedly superior knowledge of my informer and went over to the library with a due measure of assurance. the first attendant whom i addressed referred me to the assistant librarian, and he again to the librarian. after these formalities, conducted with impressive gravity, my assurance wilted when i was ushered into the august presence of the chief librarian. as the mental picture of the ensuing scene has shaped itself through more than forty years it shows a personage of imposing presence, gigantic features, and forbidding countenance, standing on a dais behind a desk, expounding the law governing the borrowing of books from the library of harvard college to an abashed youth standing before him. i left without the book, but with a valuable addition to my knowledge of library management. we both remembered this interview, and exchanged impressions about it long years after. "i thought you the most crusty and disobliging old man i had ever seen." "and i thought _you_ the most presumptuous youth that had ever appeared in the library." one of mr. sibley's professional doctrines was that at least one copy of everything printed was worth preserving. i strove to refute him, but long failed. half in derision, i offered the library the stub of my wash-book. instead of throwing it into the wastebasket he kept it, with the remark that the wash-book of a nineteenth century student would at some future time be of interest to the antiquarian. in due time i received a finely engraved acknowledgment of the gift. but i forced him from his position at last. he had to admit that copies of the theatre posters need not all be preserved. it would suffice to keep a few specimens. professor peirce was much more than a mathematician. like many men of the time, he was a warm lover and a cordial hater. it could not always be guessed which side of a disputed question he would take; but one might be fairly sure that he would be at one extreme or the other. as a speaker and lecturer he was very pleasing, neither impressive nor eloquent, and yet interesting from his earnestness and vivacity. for this reason it is said that he was once chosen to enforce the views of the university professors at a town meeting, where some subject of interest to them was coming up for discussion. several of the professors attended the meeting, and peirce made his speech. then a townsman rose and took the opposite side, expressing the hope that the meeting would not allow itself to be dictated to by these nabobs of harvard college. when he sat down, peirce remained in placid silence, making no reply. when the meeting broke up, some one asked peirce why he had not replied to the man. "why! did you not hear what he called us? he said we were nabobs! i so enjoyed sitting up there and seeing all that crowd look up to me as a nabob that i could not say one word against the fellow." the first of the leading astronomers whose acquaintance i made was dr. benjamin apthorp gould. knowing his eminence, i was quite surprised by his youthful vivacity. his history, had i time to recount it, might be made to serve well the purpose of a grave lesson upon the conditions required, even by the educated public, of a scientific investigator, capable of doing the highest and best work in his branch. the soul of generosity and the pink of honor, ever ready to lend a hand to a struggling youth whom he found deserving of help, enthusiastically devoted to his favorite science, pursuing it in the most exalted spirit, animated by not a single mean motive, it might have been supposed that all the facilities the world could offer would have been open to him in his career. if such was not the case to the extent one might have wished, i do not mean to intimate that his life can be regarded as a failure. in whatever respect the results may have fallen off from his high ideal, it is more to be regretted on the score of science than on his own. scorning pretense and charlatanry of all kinds, believing that only the best were to be encouraged, he was far from being a man of the people. only a select few enjoyed his favor, but these few well deserved it. that no others would have deserved it i should be far from intimating. the undisguised way in which he expressed his sentiments for any one, no matter how influential, who did not come up to the high standard he set, was not adapted to secure the favor even of the most educated community. of worldly wisdom in this matter he seemed, at least in his early days, to know nothing. he graduated at harvard in 1845, in one of the very distinguished classes. being fond of astronomy, he was struck with the backward condition of that science in our country. he resolved to devote his life to building up the science in america. he went to germany, then the only country in which astronomy was pursued in its most advanced form, studied under gauss and argelander, and took his degree at göttingen in 1848. soon after his return he founded the "astronomical journal," and also took a position as chief of the longitude department in the coast survey. the great misfortune of his life, and temporarily at least, a severe blow to american astronomy, were associated with his directorship of the dudley observatory at albany. this institution was founded by the munificence of a wealthy widow of albany. the men to whom she intrusted the administration of her gift were among the most prominent and highly respected citizens of the place. the trustees went wisely to work. they began by forming an advisory scientific council, consisting of bache, henry, and peirce. under the direction of this council the observatory was built and equipped with instruments. when ready for active work in 1857, gould moved thither and took personal charge. very soon rumors of dissension were heard. the affair gradually grew into a contest between the director and the trustees, exceeding in bitterness any i have ever known in the world of learning or even of politics. it doubtless had its origin in very small beginnings. the policy of the director recognized no end but scientific efficiency. the trustees, as the responsible administrators of the trust, felt that they had certain rights in the matter, especially that of introducing visitors to inspect the institution and look through the telescope. how fatal the granting of such courtesies is to continuous work with an instrument only astronomers know; and one of the most embarrassing difficulties the director of such an institution meets with is to effect a prudent compromise between the scientific efficiency of his institution and the wishes of the public. but gould knew no such word as compromise. it was humiliating to one in the position of a trustee to send some visitor with a permit to see the observatory, and have the visitor return with the report that he had not been received with the most distinguished courtesy, and, perhaps, had not seen the director at all, but had only been informed by an assistant of the rules of the place and the impossibility of securing admission. this spark was enough to kindle a fire. when the fire gathered strength, the director, instead of yielding, called on the scientific council for aid. it is quite likely that, had these wise and prudent men been consulted at each step, and their advice been followed, he would have emphasized his protest by resigning. but before they were called in, the affair had gone so far that, believing the director to be technically right in the ground he had taken and the work he had done, the council felt bound to defend him. the result was a war in which the shots were pamphlets containing charges, defenses, and rejoinders. the animosity excited may be shown by the fact that the attacks were not confined to gould and his administration, but extended to every institution with which he and the president of the council were supposed to be connected. bache's administration of the coast survey was held up to scorn and ridicule. it was supposed that gould, as a cambridge astronomer, was, as a matter of course, connected with the nautical almanac office, and paid a high salary. this being assumed, the office was included in the scope of attack, and with such success that the item for its support for the year 1859, on motion of mr. dawes, was stricken out of the naval bill. how far the fire spread may be judged by the fact that a whole edition of the "astronomical journal," supposed to have some mention of the affair in the same cover, was duly sent off from the observatory, but never reached its destination through the mails. gould knew nothing of this fact until, some weeks later, i expressed my surprise to him at not receiving no. 121. how or by whom it was intercepted, i do not know that he ever seriously attempted to inquire. the outcome of the matter was that the trustees asserted their right by taking forcible possession of the observatory. during my first year at cambridge i made the acquaintance of a senior in the college whose untimely death seven years later i have never ceased to deplore. this was william p. g. bartlett, son of a highly esteemed boston physician, dr. george bartlett. the latter was a brother of sidney bartlett, long the leader of the boston bar. bartlett was my junior in years, but his nature and the surrounding circumstances were such that he exercised a powerful influence upon me. his virile and aggressive honesty could not be exceeded. his mathematical abilities were of a high order, and he had no ambition except to become a mathematician. had he entered public life at washington, and any one had told me that he was guilty of a dishonest act, i should have replied, "you might as well tell me that he picked up the capitol last night and carried it off on his back." the fact that one could say so much of any man, i have always looked upon as illustrating one of the greatest advantages of having a youth go through college. the really important results i should look for are not culture or training alone, but include the acquaintance of a body of men, many of whom are to take leading positions in the world, of a completeness and intimacy that can never be acquired under other circumstances. the student sees his fellow students through and through as he can never see through a man in future years. it was, and i suppose still is, the custom for the members of a graduating class at harvard to add to their class biographies a motto expressing their aspirations or views of life. bartlett's was, "i love mathematics and hate humbug." what the latter clause would have led to in his case, had he gone out into the world, one can hardly guess. "i have had a long talk with my uncle sidney," he said to me one day. "he wants me to study law, maintaining that the wealth one can thereby acquire, and the prominence he may assume, will give him a higher position in society and public esteem than mere learning ever can. but i told him that if i could stand high in the esteem of twenty such men as cayley, sylvester, and peirce, i cared nothing to be prominent in the eyes of the rest of the world." such an expression from an eminent member of the boston bar, himself a harvard graduate, was the first striking evidence i met with that my views of the exalted nature of astronomical investigation were not shared by society at large. one of the greatest advantages i enjoyed through bartlett was an intimate acquaintance with a cultured and refined boston family. in 1858 mr. runkle founded the "mathematical monthly," having secured, in advance, the coöperation of the leading professors of the subject in the country. the journal was continued, under many difficulties, for three years. as a vehicle for publishing researches in advanced mathematics, it could not be of a high order, owing to the necessity of a subscription list. its design was therefore to interest students and professors in the subject, and thus prepare the way for the future growth of mathematical study among us. its principal feature was the offer of prize problems to students as well as prizes for essays on mathematical subjects. the first to win a prize for an essay was george w. hill, a graduate of rutgers just out of college, who presented a memoir in which the hand of the future master was evident throughout. in the general conduct of the journal bartlett and myself, though not ostensibly associate editors, were at least assistants. simple though the affair was, some of our experiences were of an interesting and, perhaps, instructive nature. soon after the first number appeared, a contribution was offered by a professor in a distant state. an important part of the article was found to be copied bodily from walton's "problems in mechanics," an english book which, it might be supposed, was not much known in this country. runkle did not want to run the risk of injuring his subscription list by offending one occupying an influential position if he could help it with honor to the journal. of course it was not a question of publishing the paper, but only of letting the author know why he did not do so,--"letting him down easy." bartlett's advice was characteristic. "just write to the fellow that we don't publish stolen articles. that's all you need say." i suggested that we might inflict on him all necessary humiliation by letting him know in the gentlest manner possible that we saw the fraud. of course runkle preferred this course, and wrote him, calling his attention to a similarity between his treatment of the subject and that of walton, which materially detracted from the novelty of the former. i think it was suggested that he get the book, if possible, and assure himself on the subject. a vigorous answer came by return of mail. he was a possessor of walton's book, knew all about the similar treatment of the subject by walton, and did not see that that should be any bar to the publication of the article. i think it was he who wound up his letter with the statement that, while he admitted the right of the editor to publish what he pleased, he, the writer, was too busy to spend his time in writing rejected articles. an eminent would-be contributor was a prominent pennsylvania politician, who had read a long and elaborate article, before some teachers' association, on an arithmetical problem about oxen eating grass, the power to solve which was taken as the highest mark of mathematical ability, among school teachers during the first half of the century. the association referred the paper to the editor of the "mathematical monthly," by whom it was, i believe, consigned to the wastebasket. the result was a good deal of correspondence, such a proceeding being rather humiliating to a man of eminence who had addressed so distinguished an assembly. the outcome of the matter was that the paper, which was much more in the nature of a legal document than of a mathematical investigation, was greatly reduced in length by its author, and then still further shorn by the editor, until it would fill only two or three pages of the journal; thus reduced, it was published. the time was not yet ripe for the growth of mathematical science among us, and any development that might have taken place in that direction was rudely stopped by the civil war. perhaps this may account for the curious fact that, so far as i have ever remarked, none of the student contributors to the journal, hill excepted, has made himself known as a mathematical investigator. not only the state of mathematical learning, but the conditions of success at that time in a mathematical text-book, are strikingly illustrated by one of our experiences. one of the leading publishing houses of educational text-books in the country issued a very complete and advanced series, from the pen of a former teacher of the subject. they were being extensively introduced, and were sent to the "mathematical monthly" for review. they were distinguished by quite apt illustrations, well fitted, perhaps, to start the poorly equipped student in the lower branches of the work, but the advanced works, at least, were simply ridiculous. a notice appeared in which the character of the books was pointed out. the evidence of the worthlessness of the entire series was so strong that the publishers had it entirely rewritten by more competent authors. now came the oddest part of the whole affair. the new series was issued under the name of the same author as the old one, just as if the acknowledgment of his total failure did not detract from the value of his name as an author. in 1860 a total eclipse of the sun was visible in british america. the shadow of the moon, starting from near vancouver's island, crossed the continent in a northeast direction, passed through the central part of the hudson bay region, crossed hudson bay itself and greenland, then inclining southward, swept over the atlantic to spain. as this was the first eclipse of the kind which had recently been visible, much interest was taken in its observation. on the part of the nautical almanac office i computed the path of the shadow and the times of crossing certain points in it. the results were laid down on a map which was published by the office. one party, fitted out in connection with the american association for the advancement of science, was sent to greenland. admiral davis desired to send another, on behalf of his own office, into the central regions of the continent. as members of this party mr. ferrel and myself were chosen. at the request of professor agassiz one of the assistants in the museum of comparative zoölogy, mr. samuel h. scudder, accompanied us. more than twenty years later mr. scudder published a little book describing some of our adventures, which was illustrated with sketches showing the experiences of a party in the wild west at that time. our course lay from st. paul across minnesota to the red river of the north, thence north to fort garry near the southern end of lake winnipeg, then over the lake and some distance up the saskatchewan river. at st. paul we paid our respects to governor ramsey, afterward senator from minnesota and secretary of war. we were much surprised at the extraordinary deference paid by the community to a mr. burbank, a leading citizen of the town, and owner of the stages which we had to engage for our journey across the country. he seemed to be a man whom every one was afraid to offend. even the local newspapers were careful what they printed about matters in which he was interested. the two or three days which we passed in getting things ready to start were rather dull. the morning after our arrival i saw, during a morning walk, on a hill just outside the town, a large new building, on which the word "athenæum" was conspicuously shown. the boston athenæum had a very fine library; is it not possible that this may have a beginning of something of the same sort? animated by this hope, i went up the hill and entered the building, which seemed to be entirely vacant. the first words that met my eyes were "bar room" painted over a door. it was simply a theatre, and i left it much disappointed. here we were joined by a young methodist clergyman,--edward eggleston,--and the four of us, with our instruments and appliances, set out on our journey of five days over the plains. on the first day we followed partly the line of a projected railway, of which the embankments had been completed, but on which work had, for some reason, been stopped to await a more prosperous season. here was our first experience of towns on paper. from the tone in which the drivers talked of the places where we were to stop over night one might have supposed that villages, if not cities, were plentiful along our track. one example of a town at that time will be enough. the principal place on our route, judging from the talk, was breckenridge. we would reach it at the end of the fourth day, where we anticipated a pleasant change after camping out in our tent for three nights. it was after dark before we arrived, and we looked eagerly for signs of the town we were approaching. the team at length stopped in front of an object which, on careful examination in the darkness, appeared to be the most primitive structure imaginable. it had no foundations, and if it had a wall at all, it was not more than two or three feet in height. imagine the roof taken off a house forty feet long and twenty feet wide and laid down on the ground, and you have the hotel and only building, unless perhaps a stable, in breckenridge at that time. the entrance was at one end. going in, a chimney was seen in the middle of the building. the floor was little more than the bare ground. on each side of the door, by the flickering light of a fire, we saw what looked like two immense boxes. a second glance showed that these boxes seemed to be filled with human heads and legs. they were, in fact, the beds of the inhabitants of breckenridge. beds for the arriving travelers, if they existed at all, which i do not distinctly remember, were in the back of the house. i think the other members of the party occupied that portion. i simply spread my blanket out on the hearth in front of the fire, wrapped up, and slept as soundly as if the bed was the softest of a regal palace. at fort garry we were received by governor mctavish, with whom captain davis had had some correspondence on the subject of our expedition, and who gave us letters to the "factors" of the hudson bay company scattered along our route. we found that the rest of our journey would have to be made in a birch bark canoe. one of the finest craft of this class was loaned us by the governor. it had been, at some former time, the special yacht of himself or some visiting notable. it was manned by eight half-breeds, men whose physical endurance i have never seen equaled. it took three or four days to get everything ready, and this interval was, of course, utilized by scudder in making his collections. he let the fishermen of the region know that he wanted specimens of every kind of fish that could be found in the lake. a very small reward stirred them into activity, and, in due time, the fish were brought to the naturalist,--but lo! all nicely dressed and fit for cooking. they were much surprised when told that all their pains in dressing their catch had spoiled it for the purposes of the visiting naturalist, who wanted everything just as it was taken from the water. slow indeed was progress through the lake. a canoe can be paddled only in almost smooth water, and we were frequently stormbound on some desolate island or point of land for two or three days at a time. when, after many adventures, some of which looked like hairbreadth escapes, we reached the saskatchewan river, the eclipse was only three or four days ahead, and it became doubtful whether we should reach our station in time for the observation. it was to come off on the morning of july 18, and, by dint of paddling for twenty-four hours at a stretch, our men brought us to the place on the evening before. now a new difficulty occurred. in the wet season the saskatchewan inundates the low flat region through which it flows, much like the nile. the country was practically under water. we found the most elevated spot we could, took out our instruments, mounted them on boxes or anything else in the shallow puddles of water, and slept in the canoe. next morning the weather was hopelessly cloudy. we saw the darkness of the eclipse and nothing more. astronomers are greatly disappointed when, having traveled halfway around the world to see an eclipse, clouds prevent a sight of it; and yet a sense of relief accompanies the disappointment. you are not responsible for the mishap; perhaps something would have broken down when you were making your observations, so that they would have failed in the best of weather; but now you are relieved from all responsibility. it was much easier to go back and tell of the clouds than it would have been to say that the telescope got disarranged at the critical moment so that the observations failed. on our return across minnesota we had an experience which i have always remembered as illustrative of the fallacy of all human testimony about ghosts, rappings, and other phenomena of that character. we spent two nights and a day at fort snelling. some of the officers were greatly surprised by a celestial phenomenon of a very extraordinary character which had been observed for several nights past. a star had been seen, night after night, rising in the east as usual, and starting on its course toward the south. but instead of continuing that course across the meridian, as stars invariably had done from the remotest antiquity, it took a turn toward the north, sunk toward the horizon, and finally set near the north point of the horizon. of course an explanation was wanted. my assurance that there must be some mistake in the observation could not be accepted, because this erratic course of the heavenly body had been seen by all of them so plainly that no doubt could exist on the subject. the men who saw it were not of the ordinary untrained kind, but graduates of west point, who, if any one, ought to be free from optical deceptions. i was confidently invited to look out that night and see for myself. we all watched with the greatest interest. in due time the planet mars was seen in the east making its way toward the south. "there it is!" was the exclamation. "yes, there it is," said i. "now that planet is going to keep right on its course toward the south." "no, it is not," said they; "you will see it turn around and go down towards the north." hour after hour passed, and as the planet went on its regular course, the other watchers began to get a little nervous. it showed no signs of deviating from its course. we went out from time to time to look at the sky. "there it is," said one of the observers at length, pointing to capella, which was now just rising a little to the east of north; "there is the star setting." "no, it is n't," said i; "there is the star we have been looking at, now quite inconspicuous near the meridian, and that star which you think is setting is really rising and will soon be higher up." a very little additional watching showed that no deviation of the general laws of nature had occurred, but that the observers of previous nights had jumped at the conclusion that two objects, widely apart in the heavens, were the same. i passed more than four years in such life, surroundings, and activities as i have described. in 1858 i received the degree of d. s. from the lawrence scientific school, and thereafter remained on the rolls of the university as a resident graduate. life in the new atmosphere was in such pleasant and striking contrast to that of my former world that i intensely enjoyed it. i had no very well marked object in view beyond continuing studies and researches in mathematical astronomy. not long after my arrival in cambridge some one, in speaking of professor peirce, remarked to me that he had a european reputation as a mathematician. it seemed to me that this was one of the most exalted positions that a man could attain, and i intensely longed for it. yet there was no hurry. reputation would come to him who deserved it by his works; works of the first class were the result of careful thought and study, and not of hurry. a suggestion had been made to me looking toward a professorship in some western college, but after due consideration, i declined to consider the matter. yet the necessity of being on the alert for some opening must have seemed quite strong, because in 1860 i became a serious candidate for the professorship of physics in the newly founded washington university at st. louis. i was invited to visit the university, and did so on my way to observe the eclipse of 1860. my competitor was lieutenant j. m. schofield of the united states army, then an instructor at west point. it will not surprise the reader to know that the man who was afterward to command the army of the united states received the preference, so i patiently waited more than another year. [1] henry holt & co.: new york, 1877. [2] _wayside sketches_, by e. j. loomis. roberts: boston [3] evangelinus apostolides sophocles, a native greek and a learned professor of the literature of his country. iv life and work at an observatory in august, 1861, while i was passing my vacation on cape ann, i received a letter from dr. gould, then in washington, informing me that a vacancy was to be filled in the corps of professors of mathematics attached to the naval observatory, and suggesting that i might like the place. i was at first indisposed to consider the proposition. cambridge was to me the focus of the science and learning of our country. i feared that, so far as the world of learning was concerned, i should be burying myself by moving to washington. the drudgery of night work at the observatory would also interfere with carrying on any regular investigation. but, on second thought, having nothing in view at the time, and the position being one from which i could escape should it prove uncongenial, i decided to try, and indited the following letter:- nautical almanac office, cambridge, mass., august 22, 1861. sir,--i have the honor to apply to you for my appointment to the office of professor of mathematics in the united states navy. i would respectfully refer you to commander charles henry davis, u. s. n., professor benjamin peirce, of harvard university, dr. benjamin a. gould, of cambridge, and professor joseph henry, secretary of the smithsonian institution, for any information respecting me which will enable you to judge of the propriety of my appointment. with high respect, your obedient servant, simon newcomb, assistant, nautical almanac. hon. gideon welles, secretary of the navy, washington, d. c. i also wrote to captain davis, who was then on duty in the navy department, telling him what i had done, but made no further effort. great was my surprise when, a month later, i found in the post-office, without the slightest premonition, a very large official envelope, containing my commission duly signed by abraham lincoln, president of the united states. the confidence in the valor, abilities, etc., of the appointee, expressed in the commission, was very assuring. accompanying it was a letter from the secretary of the navy directing me to report to the bureau of ordnance and hydrography, in washington, for such duty as it might assign me. i arrived on october 6, and immediately called on professor j. s. hubbard, who was the leading astronomer of the observatory. on the day following i reported as directed, and was sent to captain gilliss, the recently appointed superintendent of the naval observatory, before whom i stood with much trepidation. in reply to his questions i had to confess my entire inexperience in observatory work or the making of astronomical observations. a coast survey observer had once let me look through his transit instrument and try to observe the passage of a star. on the eclipse expedition mentioned in the last chapter i had used a sextant. this was about all the experience in practical astronomy which i could claim. in fact i had never been inside of an observatory, except on two or three occasions at cambridge as a visitor. the captain reassured me by saying that no great experience was expected of a newcomer, and told me that i should go to work on the transit instrument under professor yarnall, to whose care i was then confided. as the existence of a corps of professors of mathematics is peculiar to our navy, as well as an apparent, perhaps a real, anomaly, some account of it may be of interest. early in the century--one hardly knows when the practice began--the secretary of the navy, in virtue of his general powers, used to appoint men as professors of mathematics in the navy, to go to sea and teach the midshipmen the art of navigation. in 1844, when work at the observatory was about to begin, no provision for astronomers was made by congress. the most convenient way of supplying this want was to have the secretary appoint professors of mathematics, and send them to the observatory on duty. a few years later the naval academy was founded at annapolis, and a similar course was pursued to provide it with a corps of instructors. up to this time the professors had no form of appointment except a warrant from the secretary of the navy. early in the history of the academy the midshipmen burned a professor in effigy. they were brought before a court-martial on the charge of disrespect to a superior officer, but pleaded that the professor, not holding a commission, was not their superior officer, and on this plea were acquitted. congress thereupon took the matter up, provided that the number of professors should not exceed twelve, and that they should be commissioned by the president by and with the advice and consent of the senate. this raised their rank to that of a commissioned corps in the navy. they were to perform such duty as the secretary of the navy might direct, and were, for the most part, divided between the naval academy and the observatory. during the civil war some complaint was made that the midshipmen coming from the academy were not well trained in the duties of a seagoing officer; and it was supposed that this was due to too much of their time being given to scientific studies. this was attributed to the professors, with the result that nearly all those attached to the academy were detached during the four years following the close of the civil war and ordered elsewhere, mostly to the observatory. their places were taken by line officers who, in the intervals between their turns of sea duty, were made heads of departments and teachers of the midshipmen in nearly every branch. this state of things led to the enactment of a law (in 1869, i think), "that hereafter no vacancy in the grade of professors of mathematics in the navy shall be filled." in 1873 this provision was annulled by a law, again providing for a corps of twelve professors, three of whom should have the relative rank of captain, four of commander, and the remainder of lieutenant-commander or lieutenant. up to 1878 the secretary of the navy was placed under no restrictions as to his choice of a professor. he could appoint any citizen whom he supposed to possess the necessary qualifications. then it was enacted that, before appointment, a candidate should pass a medical and a professional examination. i have said that the main cause of hesitation in making my application arose from my aversion to very late night work. it soon became evident that there was less ground than i had supposed for apprehension on this point. there was a free and easy way of carrying on work which was surprising to one who had supposed it all arranged on strict plans, and done according to rule and discipline. professor yarnall, whose assistant i was, was an extremely pleasant gentleman to be associated with. although one of the most industrious workers at the observatory, there was nothing of the martinet about him. he showed me how to handle the instrument and record my observations. there was a nautical almanac and a catalogue of stars. out of these each of us could select what he thought best to observe. the custom was that one of us should come on every clear evening, make observations as long as he chose, and then go home. the transit instrument was at one end of the building and the mural circle, in charge of professor hubbard, at the other. he was weak in health, and unable to do much continuous work of any kind, especially the hard work of observing. he and i arranged to observe on the same nights; but i soon found that there was no concerted plan between the two sets of observers. the instruments were old-fashioned ones, of which mine could determine only the right ascension of a star and his only its declination; hence to completely determine the position of a celestial body, observations must be made on the same object with both instruments. but i soon found that there was no concert of action of this kind. hubbard, on the mural circle, had his plan of work; yarnall and myself, on the transit, had ours. when either hubbard or myself got tired, we could "vote it cloudy" and go out for a plate of oysters at a neighboring restaurant. in justice to captain gilliss it must be said that he was not in any way responsible for this lack of system. it grew out of the origin and history of the establishment and the inaction of congress. the desirableness of our having a national observatory of the same rank as those of other countries was pointed out from time to time by eminent statesmen from the first quarter of the century. john quincy adams had, both while he filled the presidential office and afterward, made active efforts in this direction; but there were grave doubts whether congress had any constitutional authority to erect such an institution, and the project got mixed up with parties and politics. so strong was the feeling on the subject that, when the coast survey was organized, it was expressly provided that it should not establish an astronomical observatory. the outcome of the matter was that, in 1842, when congress at length decided that we should have our national observatory, it was not called such, but was designated as a "house" to serve as a depot for charts and instruments for the navy. but every one knew that an observatory was meant. gilliss was charged with its erection, and paid a visit to europe to consult with astronomers there on its design, and to order the necessary instruments. when he got through with this work and reported it as completed he was relieved, and lieutenant matthew f. maury was appointed superintendent of the new institution. maury, although (as he wrote a few years later) quite without experience in the use of astronomical instruments, went at his work with great energy and efficiency, so that, for two or three years, the institution bade fair to take a high place in science. then he branched off into what was, from a practical standpoint, the vastly more important work of studying the winds and currents of the ocean. the epoch-making character of his investigations in this line, and their importance to navigation when ships depended on sails for their motive power, were soon acknowledged by all maritime nations, and the fame which he acquired in pursuing them added greatly to the standing of the institution at which the work was done, though in reality an astronomical outfit was in no way necessary to it. the new work was so absorbing that he seemed to have lost interest in the astronomical side of the establishment, which he left to his assistants. the results were that on this side things fell into the condition i have described, and stayed there until maury resigned his commission and cast his fortunes with the confederacy. then gilliss took charge and had to see what could be done under the circumstances. it soon became evident to him that no system of work of the first order of importance could be initiated until the instrumental equipment was greatly improved. the clocks, perfection in which is almost at the bottom of good work, were quite unfit for use. the astronomical clock with which yarnall and i made our observations kept worse time than a high-class pocket watch does to-day. the instruments were antiquated and defective in several particulars. before real work could be commenced new ones must be procured. but the civil war was in progress, and the times were not favorable to immediately securing them. that the work of the observatory was kept up was due to a feeling of pride on the part of our authorities in continuing it without interruption through the conflict. the personnel was as insufficient as the instruments. on it devolved not only the making of the astronomical observations, but the issue of charts and chronometers to the temporarily immense navy. in fact the observatory was still a depot of charts for the naval service, and continued to be such until the hydrographic office was established in 1866. in 1863 gilliss obtained authority to have the most pressing wants supplied by the construction of a great transit circle by pistor and martins in berlin. he had a comprehensive plan of work with this instrument when it should arrive, but deferred putting any such plan in operation until its actual reception. somehow the work of editing, explaining, and preparing for the press the new series of observations made by yarnall and myself with our old transit instrument devolved on me. to do this in the most satisfactory way, it was necessary to make a careful study of the methods and system at the leading observatories of other countries in the line we were pursuing, especially greenwich. here i was struck by the superiority of their system to ours. everything was there done on an exact and uniform plan, and one which seemed to me better adapted to get the best results than ours was. for the non-astronomical reader it may be remarked that after an astronomer has made and recorded his observations, a large amount of calculation is necessary to obtain the result to which they lead. making such calculations is called "reducing" the observations. now in the previous history of the observatory, the astronomers fell into the habit of every one not only making his observations in his own way, but reducing them for himself. thus it happened that yarnall had been making and reducing his observations in his own way, and i, on alternate nights, had been making and reducing mine in my way, which was modeled after the greenwich fashion, and therefore quite different from his. now i suddenly found myself face to face with the problem of putting these two heterogeneous things together so as to make them look like a homogeneous whole. i was extremely mortified to see how poor a showing would be made in the eyes of foreign astronomers. but i could do nothing more than to describe the work and methods in such a way as to keep in the background the want of system that characterized them. notwithstanding all these drawbacks of the present, the prospect of future success seemed brilliant. gilliss had the unlimited confidence of the secretary of the navy, had a family very popular in washington society, was enthusiastically devoted to building up the work of the observatory, and was drawing around him the best young men that could be found to do that work. he made it a point that his relations with his scientific subordinates should be not only official, but of the most friendly social character. all were constantly invited to his charming family circle. it was from the occasional talks thus arising that i learned the details of his plan of work with the coming instrument. in 1862 gilliss had the working force increased by the appointment of four "aides," as they were then called,--a number that was afterwards reduced to three. this was the beginning of the corps of three assistant astronomers, which is still maintained. it will be of interest to know that the first aide was asaph hall; but before his appointment was made, an impediment, which for a time looked serious, had to be overcome. gilliss desired that the aide should hold a good social and family position. the salary being only $1000, this required that he should not be married. hall being married, with a growing family, his appointment was long objected to, and it was only through much persuasion on the part of hubbard and myself that gilliss was at length induced to withdraw his objections. among other early appointees were william harkness and john a. eastman, whose subsequent careers in connection with the observatory are well known. the death of professor hubbard in 1863 led to my taking his place, in charge of the mural circle, early in september of that year. this gave me an opportunity of attempting a little improvement in the arrangements. i soon became conscious of the fact, which no one had previously taken much account of, that upon the plan of each man reducing his own observations, not only was there an entire lack of homogeneity in the work, but the more work one did at night the more he had to do by day. it was with some trepidation that i presented the case to gilliss, who speedily saw that work done with the instruments should be regarded as that of the observatory, and reduced on a uniform plan, instead of being considered as the property of the individual who happened to make it. thus was introduced the first step toward a proper official system. in february, 1865, the observatory sustained the greatest loss it had ever suffered, in the sudden death of its superintendent. what it would have grown to had he lived it is useless to guess, but there is little doubt that its history would have been quite different from what it is. soon afterward admiral davis left his position as chief of the bureau of navigation to take the subordinate one of superintendent of the observatory. this step was very gratifying to me, davis had not only a great interest in scientific work, especially astronomy, but a genuine admiration of scientific men which i have never seen exceeded, accompanied with a corresponding love of association with them and their work. in october, 1865, occurred what was, in my eyes, the greatest event in the history of the observatory. the new transit circle arrived from berlin in its boxes. now for the first time in its history, the observatory would have a meridian instrument worthy of it, and would, it was hoped, be able to do the finest work in at least one branch of astronomy. to my great delight, davis placed me in charge of it. the last three months of the year were taken up with mounting it in position and making those investigations of its peculiarities which are necessary before an instrument of the kind is put into regular use. on the 1st day of january, 1866, this was all done, and we were ready to begin operations. an opportunity thus arose of seeing what we could do in the way of a regular and well-planned piece of work. in the greater clearness of our sky, and the more southern latitude of our observatory, we had two great advantages over greenwich. looking back at his first two or three years of work at the observatory, maury wrote to a friend, "we have beaten greenwich hollow." it may be that i felt like trying to do the same thing over again. at any rate, i mapped out a plan of work the execution of which would require four years. it was a piece of what, in astronomy, is called "fundamental work," in which results are to be obtained independent of any previously obtained by other observers. it had become evident to me from our own observations, as well as from a study of those made at european observatories, that an error in the right ascension of stars, so that stars in opposite quarters of the heavens would not agree, might very possibly have crept into nearly all the modern observations at greenwich, paris, and washington. the determination of this error was no easy matter. it was necessary that, whenever possible, observations should be continued through the greater part of the twenty-four hours. one observer must be at work with comparative steadiness from nine o'clock in the morning until midnight or even dawn of the morning following. this requirement was, however, less exacting than might appear when stated. one half the nights would, as a general rule, be cloudy, and an observer was not expected to work on sunday. hence no one of the four observers would probably have to do such a day's work as this more than thirty or forty times in a year. all this was hard work enough in itself, but conditions existed which made it yet harder. no houses were then provided for astronomers, and the observatory itself was situated in one of the most unhealthy parts of the city. on two sides it was bounded by the potomac, then pregnant with malaria, and on the other two, for nearly half a mile, was found little but frame buildings filled with quartermaster's stores, with here and there a few negro huts. most of the observers lived a mile or more from the observatory; during most of the time i was two miles away. it was not considered safe to take even an hour's sleep at the observatory. the result was that, if it happened to clear off after a cloudy evening, i frequently arose from my bed at any hour of the night or morning and walked two miles to the observatory to make some observation included in the programme. this was certainly a new departure from the free and easy way in which we had been proceeding, and it was one which might be unwelcome to any but a zealous astronomer. as i should get the lion's share of credit for its results, whether i wanted to or not, my interest in the work was natural. but it was unreasonable to expect my assistants, one or two of whom had been raised to the rank of professor, to feel the same interest, and it is very creditable to their zeal that we pursued it for some time as well as we did. if there was any serious dissatisfaction with the duty, i was not informed of that fact. during the second year of this work admiral davis was detached and ordered to sea. the question of a successor interested many besides ourselves. secretary welles considered the question what policy should be pursued in the appointment. professor henry took part in the matter by writing the secretary a letter, in which he urged the appointment of an astronomer as head of the institution. his position prevented his supporting any particular candidate; so he submitted a list of four names, any one of which would be satisfactory. these were: professor william chauvenet, dr. b. a. gould, professor j. h. c. coffin, u. s. n., and mr. james ferguson. the latter held a civil position at the observatory, under the title of "assistant astronomer," and was at the time the longest in service of any of its force. a different view was urged upon the secretary in terms substantially these: "professors so able as those of the observatory require no one to direct their work. all that the observatory really needs is an administrative head who shall preserve order, look after its business generally, and see that everything goes smoothly." such a head the navy can easily supply. the secretary allowed it to be given out that he would be glad to hear from the professors upon the subject. i thereupon went to him and expressed my preference for professor coffin. he asked me, "how would it do to have a purely administrative head?" i replied that we might get along for a time if he did not interfere with our work. "no," said the secretary, "he shall not interfere. that shall be understood." as i left him there was, to my inexperienced mind, something very odd in this function, or absence of function, of the head of an establishment; but of course i had to bow to superior wisdom and could say nothing. the policy of commodore (afterward rear-admiral) sands, the incoming superintendent, toward the professors was liberal in the last degree. each was to receive due credit for what he did, and was in every way stimulated to do his best at any piece of scientific work he might undertake with the approval of the superintendent. whether he wanted to observe an eclipse, determine the longitude of a town or interior station, or undertake some abstruse investigation, every facility for doing it and every encouragement to go on with it was granted him. under this policy the observatory soon reached the zenith of its fame and popularity. whenever a total eclipse of the sun was visible in an accessible region parties were sent out to observe it. in 1869 three professors, i being one, were sent to des moines, iowa, to observe the solar eclipse which passed across the country in june of that year. as a part of this work, i prepared and the observatory issued a detailed set of instructions to observers in towns at each edge of the shadow-path to note the short duration of totality. the object was to determine the exact point to which the shadow extended. at this same eclipse professor harkness shared with professor young of princeton the honor of discovering the brightest line in the spectrum of the sun's corona. the year following parties were sent to the mediterranean to observe an eclipse which occurred in december, 1870. i went to gibraltar, although the observation of the eclipse was to me only a minor object. some incidents connected with this european trip will be described in a subsequent chapter. the reports of the eclipse parties not only described the scientific observations in great detail, but also the travels and experiences, and were sometimes marked by a piquancy not common in official documents. these reports, others pertaining to longitude, and investigations of various kinds were published in full and distributed with great liberality. all this activity grew out of the stimulating power and careful attention to business of the head of the observatory and the ability of the young professors of his staff. it was very pleasant to the latter to wear the brilliant uniform of their rank, enjoy the protection of the navy department, and be looked upon, one and all, as able official astronomers. the voice of one of our scientific men who returned from a visit abroad declaring that one of our eclipse reports was the laughing-stock of europe was drowned in the general applause. in the latter part of 1869 i had carried forward the work with the transit circle as far as it could be profitably pursued under existing conditions. on working up my observations, the error which i had suspected in the adopted positions of the stars was proved to be real. but the discovery of this error was due more to the system of observation, especially the pursuit of the latter through the day and night, than it was to any excellence of the instrument. the latter proved to have serious defects which were exaggerated by the unstable character of the clayey soil of the hill on which the observatory was situated. other defects also existed, which seemed to preclude the likelihood that the future work of the instrument would be of a high class. i had also found that very difficult mathematical investigations were urgently needed to unravel one of the greatest mysteries of astronomy, that of the moon's motion. this was a much more important work than making observations, and i wished to try my hand at it. so in the autumn i made a formal application to the secretary of the navy to be transferred from the observatory to the nautical almanac office for the purpose of engaging in researches on the motion of the moon. on handing this application to the superintendent he suggested that the work in question might just as well be done at the observatory. i replied that i thought that the business of the observatory was to make and reduce astronomical observations with its instruments, and that the making of investigations of the kind i had in view had always been considered to belong to the nautical almanac office. he replied that he deemed it equally appropriate for the observatory to undertake it. as my objection was founded altogether on a principle which he refused to accept, and as by doing the work at the observatory i should have ready access to its library, i consented to the arrangement he proposed. accordingly, in forwarding my application, he asked that my order should be so worded as not to detach me from the observatory, but to add the duty i asked for to that which i was already performing. so far as i was personally concerned, this change was fortunate rather than otherwise. as things go in washington, the man who does his work in a fine public building can gain consideration for it much more readily than if he does it in a hired office like that which the "nautical almanac" then occupied. my continued presence on the observatory staff led to my taking part in two of the great movements of the next ten years, the construction and inauguration of the great telescope and the observations of the transit of venus. but for the time being my connection with the regular work of the observatory ceased. on the retirement of admiral sands in 1874, admiral davis returned to the observatory, and continued in charge until his death in february, 1877. the principal event of this second administration was the dispatch of parties to observe the transit of venus. of this i shall speak in full in a subsequent chapter. one incident, although of no public importance, was of some interest at the time. this was a visit of the only emperor who, i believe, had ever set foot on our shores,--dom pedro of brazil. he had chosen the occasion of our centennial for a visit to this country, and excited great interest during his stay, not only by throwing off all imperial reserve during his travels, but by the curiosity and vigor with which he went from place to place examining and studying everything he could find, and by the singular extent of his knowledge on almost every subject of a scientific or technical character. a philadelphia engineer with whom he talked was quoted as saying that his knowledge of engineering was not merely of the ordinary kind to be expected in an intelligent man, but extended to the minutest details and latest improvements in the building of bridges, which was the specialty of the engineer in question. almost as soon as he arrived in washington i received the following letter by a messenger from the arlington hotel:- mr.: en arrivant à washington j'ai tout-de-suite songé à votre observatoire, où vous avez acquis tant de droit à l'estime de tout ceux qui achèvent la science. je m'y rendrai donc aujourd'hui à 7 heures du soir, et je compte vous y trouver, surtout pour vous remercier de votre beau mémoire que j'ai reçu peu avant mon départ de mon pays, et que je n'ai pas pu, par conséquent, apprécier autant que je l'aurais voulu. en me plaisant de l'espoir de vous connaître personnellement je vous prie de me compter parmi vos affectionnés. d. pedro d'alcantara. 7 mai, 1876. like other notes which i subsequently received from him, it was in his own autograph throughout: if he brought any secretary with him on his travels i never heard of it. the letter placed me in an embarrassing position, because its being addressed to me was in contravention of all official propriety. of course i lost no time in calling on him and trying to explain the situation. i told him that admiral davis, whom he well knew from his being in command of the brazilian station a few years before, was the head of the observatory, and hinted as plainly as i could that a notification of the coming of such a visitor as he should be sent to the head of the institution. but he refused to take the hint, and indicated that he expected me to arrange the whole matter for him. this i did by going to the observatory and frankly explaining the matter to admiral davis. happily the latter was not a stickler for official forms, and was cast in too large a mould to take offense where none was intended. at his invitation i acted as one of the receiving party. the carriage drove up at the appointed hour, and its occupant was welcomed by the admiral at the door with courtly dignity. the visitor had no time to spend in preliminaries; he wished to look through the establishment immediately. the first object to meet his view was a large marble-cased clock which, thirty years before, had acquired some celebrity from being supposed to embody the first attempt to apply electricity to the recording of astronomical observations. it was said to have cost a large sum, paid partly as a reward to its inventor. its only drawbacks were that it would not keep time and had never, so far as i am aware, served any purpose but that of an ornament. the first surprise came when the visitor got down on his hands and knees in front of the clock, reached his hands under it, and proceeded to examine its supports. we all wondered what it could mean. when he arose, it was explained. he did not see how a clock supported in this way could keep the exact time necessary in the work of an astronomer. so we had to tell him that the clock was not used for this purpose, and that he must wait until we visited the observing rooms to see our clocks properly supported. the only evidence of the imperial will came out when he reached the great telescope. the moon, near first quarter, was then shining, but the night was more than half cloudy, and there was no hope of obtaining more than a chance glimpse at it through the clouds. but he wished to see the moon through the telescope. i replied that the sky was now covered, and it was very doubtful whether we should get a view of the moon. but he required that the telescope should be at once pointed at it. this was done, and at that moment a clear space appeared between the clouds. i remarked upon the fact, but he seemed to take it as a matter of course that the cloud would get out of the way when he wanted to look. i made some remark about the "vernier" of one of the circles on the telescope. "why do you call it a vernier?" said he. "its proper term is a nonius, because nonius was its inventor and vernier took the idea from him." in this the national spirit showed itself. nonius, a portuguese, had invented something on a similar principle and yet essentially different from the modern vernier, invented by a frenchman of that name. accompanying the party was a little girl, ten or twelve years old, who, though an interested spectator, modestly kept in the background and said nothing. on her arrival home, however, she broke her silence by running upstairs with the exclamation,-"oh, mamma, he's the funniest emperor you ever did see!" my connection with the observatory ceased september 15, 1877, when i was placed in charge of the nautical almanac office. it may not, however, be out of place to summarize the measures which have since been taken both by the navy department and by eminent officers of the service to place the work of the institution on a sound basis. one great difficulty in doing this arises from the fact that neither congress nor the navy department has ever stated the object which the government had in view in erecting the observatory, or assigned to it any well-defined public functions. the superintendent and his staff have therefore been left to solve the question what to do from time to time as best they could. in the spring of 1877 rear-admiral john rodgers became the superintendent of the observatory. as a cool and determined fighter during the civil war he was scarcely second even to farragut, and he was at the same time one of the ablest officers and most estimable men that our navy ever included in its ranks. "i would rather be john rodgers dead than any other man i know living," was said by one of the observatory assistants after his death. not many months after his accession he began to consider the question whether the wide liberty which had been allowed the professors in choosing their work was adapted to attain success. the navy department also desired to obtain some expressions of opinion on the subject. the result was a discussion and an official paper, not emanating from the admiral, however, in which the duty of the head of the observatory was defined in the following terms:-"the superintendent of the observatory should be a line officer of the navy, of high rank, who should attend to the business affairs of the institution, thus leaving the professors leisure for their proper work." although he did not entirely commit himself to this view, he was under the impression that to get the best work out of the professors their hearts must be in it; and this would not be the case if any serious restraint was placed upon them as to the work they should undertake. after rodgers's death vice-admiral rowan was appointed superintendent. about this time it would seem that the department was again disposed to inquire into the results of the liberal policy heretofore pursued. commander (since rear-admiral) william t. sampson was ordered to the observatory, not as its head, but as assistant to the superintendent. he was one of the most proficient men in practical physics that the navy has ever produced. i believe that one reason for choosing so able and energetic an officer for the place was to see if any improvement could be made on the system. as i was absent at the cape of good hope to observe the transit of venus during the most eventful occasion of his administration, i have very little personal knowledge of it. it seems, however, that newspaper attacks were made on him, in which he was charged with taking possession of all the instruments of the observatory but two, and placing them in charge of naval officers who were not proficient in astronomical science. in reply he wrote an elaborate defense of his action to the "new york herald," which appeared in the number for february 13, 1883. the following extract is all that need find a place in the present connection. when i came here on duty a little more than a year since, i found these instruments disused. the transit instrument had not been used since 1878, and then only at intervals for several years previous; the mural circle had not been used since 1877; the prime vertical had not been used since 1867. these instruments had been shamefully neglected and much injured thereby. . . . the small equatorial and comet seeker were in the same disgraceful condition, and were unfit for any real work. admiral franklin was made superintendent sometime in 1883, i believe, and issued an order providing that the work of the observatory should be planned by a board consisting of the superintendent, the senior line officer, and the senior professor. professors or officers in charge of instruments were required to prepare a programme for their proposed work each year in advance, which programme would be examined by the board. of the work of this board or its proceedings, no clear knowledge can be gleaned from the published reports, nor do i know how long it continued. in 1885 secretary whitney referred to the national academy of sciences the question of the advisability of proceeding promptly with the erection of a new naval observatory upon the site purchased in 1880. the report of the academy was in the affirmative, but it was added that the observatory should be erected and named as a national one, and placed under civilian administration. the year following congress made the preliminary appropriation for the commencement of the new building, but no notice was taken of the recommendation of the academy. in 1891 the new buildings were approaching completion, and secretary tracy entered upon the question of the proper administration of the observatory. he discussed the subject quite fully in his annual report for that year, stating his conclusion in the following terms:- i therefore recommend the adoption of legislation which shall instruct the president to appoint, at a sufficient salary, without restriction, from persons either within or outside the naval service, the ablest and most accomplished astronomer who can be found for the position of superintendent. at the following session of congress senator hale introduced an amendment to the naval appropriation bill, providing for the expenses of a commission to be appointed by the secretary of the navy, to consider and report upon the organization of the observatory. the house non-concurred in this amendment, and it was dropped from the bill. at the same session, all the leading astronomers of the country united in a petition to congress, asking that the recommendation of the secretary of the navy should be carried into effect. after a very patient hearing of arguments on the subject by professor boss and others, the house naval committee reported unanimously against the measure, claiming that the navy had plenty of officers able to administer the observatory in a satisfactory way, and that there was therefore no necessity for a civilian head. two years later, senator morrill offered an amendment to the legislative appropriation bill, providing that the superintendent of the observatory should be selected from civil life, and be learned in the science of astronomy. he supported his amendment by letters from a number of leading astronomers of the country in reply to questions which he had addressed to them. this amendment, after being approved by the senate naval committee, was referred by the committee on appropriations to the secretary of the navy. he recommended a modification of the measure so as to provide for the appointment of a "director of astronomy," to have charge of the astronomical work of the observatory, which should, however, remain under a naval officer as superintendent. this arrangement was severely criticised in the house by mr. thomas b. reed, of maine, and the whole measure was defeated in conference. in 1892, when the new observatory was being occupied, the superintendent promulgated regulations for its work. these set forth in great detail what the observatory should do. its work was divided into nine departments, each with its chief, besides which there was a chief astronomical assistant and a chief nautical assistant to the superintendent, making eleven chiefs in all. the duties of each chief were comprehensively described. as the entire scientific force of the observatory numbered some ten or twelve naval officers, professors, and assistant astronomers, with six computers, it may be feared that some of the nine departments were short-handed. in september, 1894, new regulations were established by the secretary of the navy, which provided for an "astronomical director," who was to "have charge of and to be responsible for the direction, scope, character, and preparation for publication of all work purely astronomical, which is performed at the naval observatory." as there was no law for this office, it was filled first by the detail of professor harkness, who served until his retirement in 1899, then by the detail of professor brown, who served until march, 1901. in 1899 the secretary of the navy appointed a board of visitors to the observatory, comprising senator chandler, of new hampshire, hon. a. g. dayton, house of representatives, and professors pickering, comstock, and hale. this board, "in order to obviate a criticism that the astronomical work of the observatory has not been prosecuted with that vigor and continuity of purpose which should be shown in a national observatory," recommended that the astronomical director and the director of the nautical almanac should be civil officers, with sufficient salaries. a bill to this effect was introduced into each house of congress at the next session, and referred to the respective naval committees, but never reported. in 1901 congress, in an amendment to the naval appropriation bill, provided a permanent board of visitors to the observatory, in whom were vested full powers to report upon its condition and expenditures, and to prescribe its plan of work. it was also provided in the same law that the superintendent of the observatory should, until further legislation by congress, be a line officer of the navy of a rank not below that of captain. in the first annual report of this board is the following clause:-"we wish to record our deliberate and unanimous judgment that the law should be changed so as to provide that the official head of the observatory--perhaps styled simply the director--should be an eminent astronomer appointed by the president by and with the consent of the senate." although the board still has a legal existence, congress, in 1902, practically suspended its functions by declining to make any appropriation for its expenses. moreover, since the detachment of professor brown, astronomical director, no one has been appointed to fill the vacancy thus arising. at the time of the present writing, therefore, the entire responsibility for planning and directing the work of the observatory is officially vested in the naval superintendent, as it was at the old observatory. v great telescopes and their work one hardly knows where, in the history of science, to look for an important movement that had its effective start in so pure and simple an accident as that which led to the building of the great washington telescope, and went on to the discovery of the satellites of mars. very different might have been a chapter of astronomical history, but for the accident of mr. cyrus field, of atlantic cable fame, having a small dinner party at the arlington hotel, washington, in the winter of 1870. among the guests were senators hamlin and casserly, mr. j. e. hilgard of the coast survey, and a young son of mr. field, who had spent the day in seeing the sights of washington. being called upon for a recital of his experiences, the youth described his visit to the observatory, and expressed his surprise at finding no large telescope. the only instrument they could show him was much smaller and more antiquated than that of mr. rutherfurd in new york. the guests listened to this statement with incredulity, and applied to mr. hilgard to know whether the visitor was not mistaken, through a failure to find the great telescope of the observatory. mr. hilgard replied that the statement was quite correct, the observatory having been equipped at a time when the construction of great refracting telescopes had not been commenced, and even their possibility was doubted. "this ought not to be," said one of the senators. "why is it so?" mr. hilgard mentioned the reluctance of congress to appropriate money for a telescope. "it must be done," replied the senator. "you have the case properly represented to congress, and we will see that an appropriation goes through the senate at least." it chanced that this suggestion had an official basis which was not known to the guests. although mr. alvan clark had already risen into prominence as a maker of telescopes, his genius in this direction had not been recognized outside of a limited scientific circle. the civil war had commenced just as he had completed the largest refracting telescope ever made, and the excitement of the contest, as well as the absorbing character of the questions growing out of the reconstruction of the union, did not leave our public men much time to think about the making of telescopes. mr. clark had, however, been engaged by captain gilliss only a year or two after the latter had taken charge of the observatory, to come to washington, inspect our instruments, and regrind their glasses. the result of his work was so striking to the observers using the instruments before and after his work on them, that no doubt of his ability could be felt. accordingly, in preparing items for the annual reports of the observatory for the years 1868 and 1869, i submitted one to the superintendent setting forth the great deficiency of the observatory in respect to the power of its telescope, and the ability of mr. clark to make good that deficiency. these were embodied in the reports. it was recommended that authority be given to order a telescope of the largest size from mr. clark. it happened, however, that secretary welles had announced in his annual reports as his policy that he would recommend no estimates for the enlargement and improvement of public works in his department, but would leave all matters of this kind to be acted on by congress as the latter might deem best. as the telescope was thrown out of the regular estimates by this rule, this subject had failed to be considered by congress. now, however, the fact of the recommendation appearing in the annual report, furnished a basis of action. mr. hilgard did not lose a day in setting the ball in motion. he called upon me immediately, and i told him of the recommendations in the last two reports of the superintendent of the observatory. together we went to see admiral sands, who of course took the warmest interest in the movement, and earnestly promoted it on the official side. mr. hilgard telegraphed immediately to some leading men of science, who authorized their signatures to a petition. in this paper attention was called to the wants of the observatory, as set forth by the superintendent, and to the eminent ability of the celebrated firm of the clarks to supply them. the petition was printed and put into the hands of senator hamlin for presentation to the senate only three or four days after the dinner party. the appropriation measure was formally considered by the committee on naval affairs and that on appropriations, and was adopted in the senate as an amendment to the naval appropriation bill without opposition. the question then was to get the amendment concurred in by the house of representatives. the session was near its close, and there was no time to do much work. several members of the house committee on appropriations were consulted, and the general feeling seemed to be favorable to the amendment. great, therefore, was our surprise to find the committee recommending that the amendment be not concurred in. to prevent a possible misapprehension, i may remark that the present system of non-concurring in all amendments to an appropriation bill, in order to bring the whole subject into conference, had not then been introduced, so that this action showed a real opposition to the movement. one of the most curious features of the case is that the leader in the opposition was said to be mr. washburn, the chairman of the committee, who, not many years later, founded the washburn observatory of the university of wisconsin. there is, i believe, no doubt that his munificence in this direction arose from what he learned about astronomy and telescopes in the present case. it happened, most fortunately, that the joint committee of conference included drake of the senate and niblack of the house, both earnestly in favor of the measure. the committee recommended concurrence, and the clause authorizing the construction became a law. the price was limited to $50,000, and a sum of $10,000 was appropriated for the first payment. no sooner were the clarks consulted than difficulties were found which, for a time, threatened to complicate matters, and perhaps delay the construction. in the first place, our currency was then still on a paper basis. gold was at a premium of some ten or fifteen per cent., and the clarks were unwilling to take the contract on any but a gold basis. this, of course, the government could not do. but the difficulty was obviated through the action of a second one, which equally threatened delay. mr. l. j. mccormick, of reaping-machine fame, had conceived the idea of getting the largest telescope that could be made. he had commenced negotiations with the firm of alvan clark & sons before we had moved, and entered into a contract while the appropriation was still pending in congress. if the making of one great telescope was a tedious job, requiring many years for its completion, how could two be made? i was charged with the duty of negotiating the government contract with the clarks. i found that the fact of mr. mccormick's contract being on a gold basis made them willing to accept one from the government on a currency basis; still they considered that mr. mccormick had the right of way in the matter of construction, and refused to give precedence to our instrument. on mature consideration, however, the firm reached the conclusion that two instruments could be made almost simultaneously, and mr. mccormick very generously waived any right he might have had to precedence in the matter. the question how large an instrument they would undertake was, of course, one of the first to arise. progress in the size of telescopes had to be made step by step, because it could never be foreseen how soon the limit might be met; and if an attempt were made to exceed it, the result would be not only failure for the instrument, but loss of labor and money by the constructors. the largest refracting telescope which the clarks had yet constructed was one for the university of mississippi, which, on the outbreak of the civil war, had come into the possession of the astronomical society of chicago. this would have been the last step, beyond which the firm would not have been willing to go to any great extent, had it not happened that, at this very time, a great telescope had been mounted in england. this was made by thomas cooke & sons of york, for mr. r. s. newall of gateshead on tyne, england. the clarks could not, of course, allow themselves to be surpassed or even equaled by a foreign constructor; yet they were averse to going much beyond the cooke telescope in size. twenty-six inches aperture was the largest they would undertake. i contended as strongly as i could for a larger telescope than mr. mccormick's, but they would agree to nothing of the sort,--the supposed right of that gentleman to an instrument of equal size being guarded as completely as if he had been a party to the negotiations. so the contract was duly made for a telescope of twenty-six inches clear aperture. at that time cooke and clark were the only two men who had ever succeeded in making refracting telescopes of the largest size. but in order to exercise their skill, an art equally rare and difficult had to be perfected, that of the glassmaker. ordinary glass, even ordinary optical glass, would not answer the purpose at all. the two disks, one of crown glass and the other of flint, must be not only of perfect transparency, but absolutely homogeneous through and through, to avoid inequality of refraction, and thus cause all rays passing through them to meet in the same focus. it was only about the beginning of the century that flint disks of more than two or three inches diameter could be made. even after that, the art was supposed to be a secret in the hands of a swiss named guinand, and his family. looking over the field, the clarks concluded that the only firm that could be relied on to furnish the glass was that of chance & co., of birmingham, england. so, as soon as the contracts were completed, one of the clark firm visited england and arranged with chance & co. to supply the glass for the two telescopes. the firm failed in a number of trials, but by repeated efforts finally reached success at the end of a year. the glasses were received in december, 1871, and tested in the following month. a year and a half more was required to get the object glasses into perfect shape; then, in the spring or summer of 1873, i visited cambridge for the purpose of testing the glasses. they were mounted in the yard of the clark establishment in a temporary tube, so arranged that the glass could be directed to any part of the heavens. i have had few duties which interested me more than this. the astronomer, in pursuing his work, is not often filled with those emotions which the layman feels when he hears of the wonderful power of the telescope. not to say anything so harsh as that "familiarity breeds contempt," we must admit that when an operation of any sort becomes a matter of daily business, the sentiments associated with it necessarily become dulled. now, however, i was filled with the consciousness that i was looking at the stars through the most powerful telescope that had ever been pointed at the heavens, and wondered what mysteries might be unfolded. the night was of the finest, and i remember, sweeping at random, i ran upon what seemed to be a little cluster of stars, so small and faint that it could scarcely have been seen in a smaller instrument, yet so distant that the individual stars eluded even the power of this instrument. what cluster it might have been it was impossible to determine, because the telescope had not the circles and other appliances necessary for fixing the exact location of an object. i could not help the vain longing which one must sometimes feel under such circumstances, to know what beings might live on planets belonging to what, from an earthly point of view, seemed to be a little colony on the border of creation itself. in his report dated october 9, 1873, admiral sands reported the telescope as "nearly completed." the volume of washington observations showed that the first serious observations made with it, those on the satellites of neptune, were commenced on november 10 of the same year. thus, scarcely more than a month elapsed from the time that the telescope was reported still incomplete in the shop of its makers until it was in regular nightly use. associated with the early history of the instrument is a chapter of astronomical history which may not only instruct and amuse the public, but relieve the embarrassment of some astronomer of a future generation who, reading the published records, will wonder what became of an important discovery. if the faith of the public in the absolute certainty of all astronomical investigation is thereby impaired, what i have to say will be in the interest of truth; and i have no fear that our science will not stand the shock of the revelation. of our leading astronomical observers of the present day--of such men as burnham and barnard--it may be safely said that when they see a thing it is there. but this cannot always be said of every eminent observer, and here is a most striking example of this fact. when the telescope was approaching completion i wrote to the head of one of the greatest european observatories, possessing one of the best telescopes of the time, that the first thing i should attempt with the telescope would be the discovery of the companion of procyon. this first magnitude star, which may be well seen in the winter evenings above orion, had been found to move in an exceedingly small orbit, one too small to be detected except through the most refined observations of modern precision. the same thing had been found in the case of sirius, and had been traced to the action of a minute companion revolving around it, which was discovered by the clarks a dozen years before. there could be no doubt that the motion of procyon was due to the same cause, but no one had ever seen the planet that produced it, though its direction from the star at any time could be estimated. now, it happened that my european friend, as was very natural, had frequently looked for this object without seeing it. whether my letter set him to looking again, or whether he did not receive it until a later day, i do not know. what is certain is that, in the course of the summer, he published the discovery of the long-looked-for companion, supplemented by an excellent series of observations upon it, made in march and april. of course i was a little disappointed that the honor of first finding this object did not belong to our own telescope. still i was naturally very curious to see it. so, on the very first night on which the telescope could be used, i sat up until midnight to take a look at procyon, not doubting that, with the greater power of our telescope, it would be seen at the first glance. to my great concern, nothing of the sort was visible. but the night was far from good, the air being somewhat thick with moisture, which gave objects seen through it a blurred appearance; so i had to await a better night and more favorable conditions. better nights came and passed, and still not a trace of the object could be seen. supposing that the light of the bright star might be too dazzling, i cut it off with a piece of green glass in the focus. still no companion showed itself. could it be that our instrument, in a more favorable location, would fail to show what had been seen with one so much smaller? this question i could not answer, but wrote to my european friend of my unavailing attempts. he replied expressing his perplexity and surprise at the occurrence, which was all the greater that the object had again been seen and measured in april, 1874. a fine-looking series of observations was published, similar to those of the preceding year. what made the matter all the more certain was that there was a change in the direction of the object which corresponded very closely to the motion as it had been predicted by auwers. the latter published a revision of his work, based on the new observations. a year later, the parties that had been observing the transit of venus returned home. the head of one of them, professor c. h. f. peters of clinton, stopped a day or two at washington. it happened that a letter from my european friend arrived at the same time. i found that peters was somewhat skeptical as to the reality of the object. sitting before the fire in my room at the observatory, i read to him and some others extracts from the letter, which cited much new evidence to show the reality of the discovery. not only had several of his own observers seen the object, but it had been seen and measured on several different nights by a certain professor blank, with a telescope only ten or twelve inches aperture. "what," said peters, "has blank seen it?" "yes, so the letter says." "then it is n't there!" and it really was not there. the maker of the discovery took it all back, and explained how he had been deceived. he found that the telescope through which the observations were made seemed to show a little companion of the same sort alongside of every very bright star. everything was explained by this discovery. even the seeming motion of the imaginary star during the twelve months was accounted for by the fact that in 1873 procyon was much nearer the horizon when the observations were made than it was the year following. [1] there is a sequel to the history, which may cause its revision by some astronomer not many years hence. when the great telescope was mounted at the lick observatory, it is understood that burnham and barnard, whose eyes are of the keenest, looked in vain for the companion of procyon. yet, in 1895, it was found with the same instrument by schaeberle, and has since been observed with the great yerkes telescope, as well as by the observers at mount hamilton, so that the reality of the discovery is beyond a doubt. the explanation of the failure of burnham and barnard to see it is very simple: the object moves in an eccentric orbit, so that it is nearer the planet at some points of its orbit than at others. it was therefore lost in the rays of the bright star during the years 1887-94. is it possible that it could have been far enough away to be visible in 1873-74? i need scarcely add that this question must be answered in the negative, yet it may be worthy of consideration, when the exact orbit of the body is worked out twenty or thirty years hence. in my work with the telescope i had a more definite end in view than merely the possession of a great instrument. the work of reconstructing the tables of the planets, which i had long before mapped out as the greatest one in which i should engage, required as exact a knowledge as could be obtained of the masses of all the planets. in the case of uranus and neptune, the two outer planets, this knowledge could best be obtained by observations on their satellites. to the latter my attention was therefore directed. in the case of neptune, which has only one satellite yet revealed to human vision, and that one so close to the planet that the observations are necessarily affected by some uncertainty, it was very desirable that a more distant one should be found if it existed. i therefore during the summer and autumn of 1874 made most careful search under the most favorable conditions. but no second satellite was found. i was not surprised to learn that the observers with the great lick telescope were equally unsuccessful. my observations with the instrument during two years were worked up and published, and i turned the instrument over to professor hall in 1875. the discovery of the satellites of mars was made two years later, in august, 1877. as no statement that i took any interest in the discovery has ever been made in any official publication, i venture, with the discoverer's permission, to mention the part that i took in verifying it. one morning professor hall confidentially showed me his first observations of an object near mars, and asked me what i thought of them. i remarked, "why, that looks very much like a satellite." yet he seemed very incredulous on the subject; so incredulous that i feared he might make no further attempt to see the object. i afterward learned, however, that this was entirely a misapprehension on my part. he had been making a careful search for some time, and had no intention of abandoning it until the matter was cleared up one way or the other. the possibility of the object being an asteroid suggested itself. i volunteered to test this question by looking at the ephemerides of all the small planets in the neighborhood of mars. a very little searching disproved the possibility of the object belonging to this class. one such object was in the neighborhood, but its motion was incompatible with the measures. then i remarked that, if the object were really a satellite, the measures already made upon it, and the approximately known mass of the planet, would enable the motion of the satellite to be determined for a day or two. thus i found that on that night the satellite would be hidden in the early evening by the planet, but would emerge after midnight. i therefore suggested to professor hall that, if it was not seen in the early evening, he should wait until after midnight. the result was in accordance with the prediction,--the satellite was not visible in the early evening, but came out after midnight. no further doubt was possible, and the discovery was published. the labor of searching and observing was so exhausting that professor hall let me compute the preliminary orbit of the satellites from his early observations. my calculations and suggestions lost an importance they might otherwise have claimed, for the reason that several clear nights followed. had cloudy weather intervened, a knowledge of when to look for the object might have greatly facilitated its recognition. it is still an open question, perhaps, whether a great refracting telescope will last unimpaired for an indefinite length of time. i am not aware that the twin instruments of harvard and pulkowa, mounted in 1843, have suffered from age, nor am i aware that any of alvan clark's instruments are less perfect to-day than when they left the hands of their makers. but not long after the discovery of the satellites of mars, doubts began to spread in some quarters as to whether the great washington telescope had not suffered deterioration. these doubts were strengthened in the following way: when hundreds of curious objects were being discovered in the heavens here and there, observers with small instruments naturally sought to find them. the result was several discoveries belonging to the same class as that of the satellite of procyon. they were found with very insignificant instruments, but could not be seen in the large ones. professor hall published a letter in a european journal, remarking upon the curious fact that several objects were being discovered with very small instruments, which were invisible in the washington telescope. this met the eye of professor wolf, a professor at the sorbonne in paris, as well as astronomer at the paris observatory. in a public lecture, which he delivered shortly afterward, he lamented the fact that the deterioration of the washington telescope had gone so far as that, and quoted professor hall as his authority. the success of the washington telescope excited such interest the world over as to give a new impetus to the construction of such instruments. its glass showed not the slightest drawbacks from its great size. it had been feared that, after a certain limit, the slight bending of the glass under its own weight would be injurious to its performance. nothing of the kind being seen, the clarks were quite ready to undertake much larger instruments. a 30-inch telescope for the pulkova observatory in russia, the 36-inch telescope of the lick observatory in california, and, finally, the 40-inch of the yerkes observatory in chicago, were the outcome of the movement. of most interest to us in the present connection is the history of the 30-inch telescope of the pulkova observatory, the object glass of which was made by alvan clark & sons. it was, i think, sometime in 1878 that i received a letter from otto struve, [2] director of the pulkova observatory, stating that he was arranging with his government for a grant of money to build one of the largest refracting telescopes. in answering him i called his attention to the ability of alvan clark & sons to make at least the object glass, the most delicate and difficult part of the instrument. the result was that, after fruitless negotiations with european artists, struve himself came to america in the summer of 1879 to see what the american firm could do. he first went to washington and carefully examined the telescope there. then he proceeded to cambridge and visited the workshop of the clarks. he expressed some surprise at its modest dimensions and fittings generally, but was so well pleased with what he saw that he decided to award them the contract for making the object glass. he was the guest of the pickerings at the cambridge observatory, and invited me thither from where i was summering on the coast of massachusetts to assist in negotiating the contract. he requested that, for simplicity in conference, the preliminary terms should be made with but a single member of the firm to talk with. george b. clark, the eldest member, was sent up to represent the firm. i was asked to take part in the negotiations as a mutual friend of both parties, and suggested the main conditions of the contract. a summary of these will be found in the publication to which i have already referred. there was one provision the outcome of which was characteristic of alvan clark & sons. struve, in testing some object glasses which they had constructed and placed in their temporary tube, found so great physical exertion necessary in pointing so rough an instrument at any heavenly body with sufficient exactness, that he could not form a satisfactory opinion of the object glass. as he was to come over again when the glass was done, in order to test it preliminary to acceptance, he was determined that no such difficulty should arise. he therefore made a special provision that $1000 extra, to be repaid by him, should be expended in making a rough equatorial mounting in which he could test the instrument. george clark demurred to this, on the ground that such a mounting as was necessary for this purpose could not possibly cost so much money. but struve persistently maintained that one to cost $1000 should be made. the other party had to consent, but failed to carry out this provision. the tube was, indeed, made large enough to test not only struve's glass but the larger one of the lick observatory, which, though not yet commenced, was expected to be ready not long afterward. yet, notwithstanding this increase of size, i think the extra cost turned out to be much less than $1000, and the mounting was so rough that when struve came over in 1883 to test the glass, he suffered much physical inconvenience and met, if my memory serves me aright, with a slight accident, in his efforts to use the rough instrument. in points like this i do not believe that another such business firm as that of the clarks ever existed in this country or any other. here is an example. shortly before the time of struve's visit, i had arranged with them for the construction of a refined and complicated piece of apparatus to measure the velocity of light. as this apparatus was quite new in nearly all its details, it was impossible to estimate in advance what it might cost; so, of course, they desired that payment for it should be arranged on actual cost after the work was done. i assured them that the government would not enter into a contract on such terms. there must be some maximum or fixed price. this they fixed at $2500. i then arranged with them that this should be taken as a maximum and that, if it was found to cost less, they should accept actual cost. the contract was arranged on this basis. there were several extras, including two most delicate reflecting mirrors which would look flat to the eye, but were surfaces of a sphere of perhaps four miles diameter. the entire cost of the apparatus, as figured up by them after it was done, with these additions, was less than $1500, or about forty per cent. below the contract limit. no set of men were ever so averse to advertising themselves. if anybody, in any part of the world, wanted them to make a telescope, he must write to them to know the price, etc. they could never be induced to prepare anything in the form of a price catalogue of the instruments they were prepared to furnish. the history of their early efforts and the indifference of our scientific public to their skill forms a mortifying chapter in our history of the middle of the century. when mr. clark had finished his first telescope, a small one of four inches aperture, which was, i have no reason to doubt, the best that human art could make, he took it to the cambridge observatory to be tested by one of the astronomers. the latter called his attention to a little tail which the glass showed as an appendage of a star, and which was, of course, non-existent. it was attributed to a defect in the glass, which was therefore considered a failure. mr. clark was quite sure that the tail was not shown when he had previously used the glass, but he could not account for it at the time. he afterwards traced it to the warm air collecting in the upper part of the tube and producing an irregular refraction of the light. when this cause was corrected the defect disappeared. but he got no further encouragement at home to pursue his work. the first recognition of his genius came from england, the agent being rev. w. r. dawes, an enthusiastic observer of double stars, who was greatly interested in having the best of telescopes. mr. clark wrote him a letter describing a number of objects which he had seen with telescopes of his own make. from this description mr. dawes saw that the instruments must be of great excellence, and the outcome of the matter was that he ordered one or more telescopes from the american maker. not until then were the abilities of the latter recognized in his own country. i have often speculated as to what the result might have been had mr. clark been a more enterprising man. if, when he first found himself able to make a large telescope, he had come to washington, got permission to mount his instrument in the grounds of the capitol, showed it to members of congress, and asked for legislation to promote this new industry, and, when he got it, advertised himself and his work in every way he could, would the firm which he founded have been so little known after the death of its members, as it now unhappily is? this is, perhaps, a rather academic question, yet not an unprofitable one to consider. in recent years the firm was engaged only to make object glasses of telescopes, because the only mountings they could be induced to make were too rude to satisfy astronomers. the palm in this branch of the work went to the firm of warner & swasey, whose mounting of the great yerkes telescope of the university of chicago is the last word of art in this direction. during the period when the reputation of the cambridge family was at its zenith, i was slow to believe that any other artist could come up to their standard. my impression was strengthened by a curious circumstance. during a visit to the strasburg observatory in 1883 i was given permission to look through its great telescope, which was made by a renowned german artist. i was surprised to find the object glass affected by so serious a defect that it could not be expected to do any work of the first class. one could only wonder that european art was so backward. but, several years afterward, the astronomers discovered that, in putting the glasses together after being cleaned, somebody had placed one of them in the wrong position, the surface which should have been turned toward the star being now turned toward the observer. when the glass was simply turned over so as to have the right face outward, the defect disappeared. [1] in justice to mr. blank, i must say that there seems to have been some misunderstanding as to his observations. what he had really seen and observed was a star long well known, much more distant from procyon than the companion in question. [2] otto struve was a brother of the very popular russian minister to washington during the years 1882-92. he retired from the direction of the pulkowa observatory about 1894. the official history of his negotiations and other proceedings for the construction of the telescope will be found in a work published in 1889 in honor of the jubilee of the observatory. vi the transits of venus it was long supposed that transits of venus over the sun's disk afforded the only accurate method of determining the distance of the sun, one of the fundamental data of astronomy. unfortunately, these phenomena are of the rarest. they come in pairs, with an interval of eight years between the transits of a pair. a pair occurred in 1761 and 1769, and again in 1874 and 1882. now the whole of the twentieth century will pass without another recurrence of the phenomenon. not until the years 2004 and 2012 will our posterity have the opportunity of witnessing it. much interesting history is associated with the adventures of the astronomers who took part in the expeditions to observe the transits of 1761 and 1769. in the almost chronic warfare which used to rage between france and england during that period, neither side was willing to regard as neutral even a scientific expedition sent out by the other. the french sent one of their astronomers, le gentil, to observe the transit at pondicherry in the east indies. as he was nearing his station, the presence of the enemy prevented him from making port, and he was still at sea on the day of the transit. when he at length landed, he determined to remain until the transit of 1769, and observe that. we must not suppose, however, that he was guilty of the eccentricity of doing this with no other object in view than that of making the observation. he found the field open for profitable mercantile enterprise, as well as interesting for scientific observations and inquiries. the eight long years passed away, and the morning of june 4, 1769, found him in readiness for his work. the season had been exceptionally fine. on the morning of the transit the sun shone in a cloudless sky, as it had done for several days previous. but, alas for all human hopes! just before venus reached the sun, the clouds gathered, and a storm burst upon the place. it lasted until the transit was over, and then cleared away again as if with the express object of showing the unfortunate astronomer how helpless he was in the hands of the elements. the royal society of england procured a grant of £800 from king george ii. for expeditions to observe the transit of 1761. [1] with this grant the society sent the rev. nevil maskelyne to the island of st. helena, and, receiving another grant, it was used to dispatch messrs. mason and dixon (those of our celebrated "line") to bencoolen. the admiralty also supplied a ship for conveying the observers to their respective destinations. maskelyne, however, would not avail himself of this conveyance, but made his voyage on a private vessel. cloudy weather prevented his observations of the transit, but this did not prevent his expedition from leaving for posterity an interesting statement of the necessaries of an astronomer of that time. his itemized account of personal expenses was as follows:- one year's board at st. helena . . £109 10s. 0d. liquors at 5s. per day . . . . 91 5 0 washing at 9d. per day . . . . 13 13 9 other expenses . . . . . . 27 7 6 liquors on board ship for six months 50 0 0 -- -- -- £291 16s. 3d. seven hundred dollars was the total cost of liquors during the eighteen months of his absence. admiral smyth concludes that maskelyne "was not quite what is now ycleped a teetotaler." he was subsequently astronomer royal of england for nearly half a century, but his published observations give no indication of the cost of the drinks necessary to their production. mason and dixon's expedition met with a mishap at the start. they had only got fairly into the english channel when their ship fell in with a french frigate of superior force. an action ensued in which the english crew lost eleven killed and thirty-eight wounded. the frenchman was driven off, but the victorious vessel had to return to plymouth for repairs. this kind of a scientific expedition was more than the astronomers had bargained for, and they wrote from plymouth to the royal society, describing their misfortune and resigning their mission. but the council of the society speedily let them know that they were unmoved by the misfortunes of their scientific missionaries, and pointed out to them in caustic terms that, having solemnly undertaken the expedition, and received money on account of it, their failure to proceed on the voyage would be a reproach to the nation in general, and to the royal society in particular. it would also bring an indelible scandal upon their character, and probably end in their utter ruin. they were assured that if they persisted in the refusal, they would be treated with the most inflexible resentment, and prosecuted with the utmost severity of the law. under such threats the unfortunate men could do nothing but accept the situation and sail again after their frigate had been refitted. when they got as far as the cape of good hope, it was found very doubtful whether they would reach their destination in time for the transit; so, to make sure of some result from their mission, they made their observations at the cape. one of the interesting scraps of history connected with the transit of 1769 concerns the observations of father maximilian hell, s. j., the leading astronomer of vienna. he observed the transit at wardhus, a point near the northern extremity of norway, where the sun did not set at the season of the transit. owing to the peculiar circumstances under which the transit was observed,--the ingress of the planet occurring two or three hours before the sun approached the northern horizon, and the end of the transit about as long afterward,--this station was the most favorable one on the globe. hell, with two or three companions, one of them named sajnovics, went on his mission to this isolated place under the auspices of the king of denmark. the day was cloudless and the observations were made with entire success. he returned to copenhagen, where he passed several months in preparing for the press a complete account of his expedition and the astronomical observations made at the station. astronomers were impatient to have the results for the distance of the sun worked out as soon as possible. owing to the importance of hell's observations, they were eagerly looked for. but he at first refused to make them known, on the ground that, having been made under the auspices of the king of denmark, they ought not to be made known in advance of their official publication by the danish academy of sciences. this reason, however, did not commend itself to the impatient astronomers; and suspicions were aroused that something besides official formalities was behind the delay. it was hinted that hell was waiting for the observations made at other stations in order that he might so manipulate his own that they would fit in with those made elsewhere. reports were even circulated that he had not seen the transit at all, owing to cloudy weather, and that he was manufacturing observations in copenhagen. the book was, however, sent to the printer quite promptly, and the insinuations against its author remained a mere suspicion for more than sixty years. then, about 1833, a little book was published on the subject by littrow, director of the vienna observatory, which excited much attention. father hell's original journal had been conveyed to vienna on his return, and was still on deposit at the austrian national observatory. littrow examined it and found, as he supposed, that the suspicions of alterations in observations were well founded; more especially that the originals of the all-important figures which recorded the critical moment of "contact" had been scraped out of the paper, and new ones inserted in their places. the same was said to be the case with many other important observations in the journal, and the conclusion to which his seemingly careful examination led was that no reliance could be placed on the genuineness of hell's work. the doubts thus raised were not dispelled until another half-century had elapsed. in 1883 i paid a visit to vienna for the purpose of examining the great telescope which had just been mounted in the observatory there by grubb, of dublin. the weather was so unfavorable that it was necessary to remain two weeks, waiting for an opportunity to see the stars. one evening i visited the theatre to see edwin booth, in his celebrated tour over the continent, play king lear to the applauding viennese. but evening amusements cannot be utilized to kill time during the day. among the tasks i had projected was that of rediscussing all the observations made on the transits of venus which had occurred in 1761 and 1769, by the light of modern science. as i have already remarked, hell's observations were among the most important made, if they were only genuine. so, during my almost daily visits to the observatory, i asked permission of director weiss to study hell's manuscript. at first the task of discovering anything which would lead to a positive decision on one side or the other seemed hopeless. to a cursory glance, the descriptions given by littrow seemed to cover the ground so completely that no future student could turn his doubt into certainty. but when one looks leisurely at an interesting object, day after day, he continually sees more and more. thus it was in the present case. one of the first things to strike me as curious was that many of the alleged alterations had been made before the ink got dry. when the writer made a mistake, he had rubbed it out with his finger, and made a new entry. the all-important point was a certain suspicious record which littrow affirmed had been scraped out so that the new insertion could be made. as i studied these doubtful figures, day by day, light continually increased. evidently the heavily written figures, which were legible, had been written over some other figures which were concealed beneath them, and were, of course, completely illegible, though portions of them protruded here and there outside of the heavy figures. then i began to doubt whether the paper had been scraped at all. to settle the question, i found a darkened room, into which the sun's rays could be admitted through an opening in the shutter, and held the paper in the sunlight in such a way that the only light which fell on it barely grazed the surface of the paper. examining the sheet with a magnifying glass, i was able to see the original texture of the surface with all its hills and hollows. a single glance sufficed to show conclusively that no eraser had ever passed over the surface, which had remained untouched. the true state of the case seemed to me almost beyond doubt. it frequently happened that the ink did not run freely from the pen, so that the words had sometimes to be written over again. when hell first wrote down the little figures on which, as he might well suppose, future generations would have to base a very important astronomical element, he saw that they were not written with a distinctness corresponding to their importance. so he wrote them over again with the hand, and in the spirit of a man who was determined to leave no doubt on the subject, little weening that the act would give rise to a doubt which would endure for a century. this, although the most important case of supposed alteration, was by no means the only one. yet, to my eyes, all the seeming corrections in the journal were of the most innocent and commonplace kind,--such as any one may make in writing. then i began to compare the manuscript, page after page, with littrow's printed description. it struck me as very curious that where the manuscript had been merely retouched with ink which was obviously the same as that used in the original writing, but looked a little darker than the original, littrow described the ink as of a different color. in contrast with this, there was an important interlineation, which was evidently made with a different kind of ink, one that had almost a blue tinge by comparison; but in the description he makes no mention of this plain difference. i thought this so curious that i wrote in my notes as follows:-"that littrow, in arraying his proofs of hell's forgery, should have failed to dwell upon the obvious difference between this ink and that with which the alterations were made leads me to suspect a defect in his sense of color." then it occurred to me to inquire whether, perhaps, such could have been the case. so i asked director weiss whether anything was known as to the normal character of littrow's power of distinguishing colors. his answer was prompt and decisive. "oh, yes, littrow was color blind to red. he could not distinguish between the color of aldebaran and that of the whitest star." no further research was necessary. for half a century the astronomical world had based an impression on the innocent but mistaken evidence of a color-blind man respecting the tints of ink in a manuscript. about the middle of the nineteenth century other methods of measuring the sun's distance began to be developed which, it was quite possible, might prove as good as the observation in question. but the relative value of these methods and of transits of venus was a subject on which little light could be thrown; and the rarity of the latter phenomena naturally excited universal interest, both among the astronomers and among the public. for the purpose in question it was necessary to send expeditions to different and distant parts of the globe, because the result had to depend upon the times of the phases, as seen from widely separated stations. in 1869 the question what stations should be occupied and what observations should be made was becoming the subject of discussion in europe, and especially in england. but our country was still silent on the subject. the result of continued silence was not hard to foresee. congress would, at the last moment, make a munificent appropriation for sending out parties to observe the transit. the plans and instruments would be made in a hurry, and the parties packed off without any well-considered ideas of what they were to do; and the whole thing would end in failure so far as results of any great scientific value were concerned. i commenced the discussion by a little paper on the subject in the "american journal of science," but there was no one to follow it up. so, at the spring meeting of the national academy of sciences, in 1870, i introduced a resolution for the appointment of a committee to consider the subject and report upon the observations which should be made. this resolution was adopted, and a few days afterward professor henry invited me to call at his office in the evening to discuss with himself and professor peirce, then superintendent of the coast survey, the composition of the committee. at the conference i began by suggesting professor peirce himself for chairman. naturally this met with no opposition; then i waited for the others to go on. but they seemed determined to throw the whole onus of the matter on me. this was the more embarrassing, because i believe that, in parliamentary law and custom, the mover of a resolution of this sort has a prescribed right to be chairman of the committee which he proposes shall be appointed. if not chairman, it would seem that he ought at any rate to be a member. but i was determined not to suggest myself in any way, so i went on and suggested admiral davis. this nomination was, of course, accepted without hesitation. then i remarked that the statutes of the academy permitted of persons who were not members being invited to serve on a committee, and as the naval observatory would naturally take a leading part in such observations as were to be made, i suggested that its superintendent, admiral sands, should be invited to serve as a member of the committee. "there," said peirce, "we now have three names. committees of three are always the most efficient. why go farther?" i suggested that the committee should have on it some one practiced in astronomical observation, but he deemed this entirely unnecessary, and so the committee of three was formed. i did not deem it advisable to make any opposition at the time, because it was easy to foresee what the result would be. during the summer nothing was heard of the committee, and in the autumn i made my first trip to europe. on my return, in may, 1871, i found that the committee had never even held a meeting, and that it had been enlarged by the addition of a number of astronomers, among them myself. but, before it went seriously to work, it was superseded by another organization, to be described presently. at that time astronomical photography was in its infancy. enough had been done by rutherfurd to show that it might be made a valuable adjunct to astronomical investigation. might we not then photograph venus on the sun's disk, and by measurements of the plates obtain the desired result, perhaps better than it could be obtained by any kind of eye observation? this question had already suggested itself to professor winlock, who, at the cambridge observatory, had designed an instrument for taking the photographs. it consisted of a fixed horizontal telescope, into which the rays of the sun were to be thrown by a reflector. this kind of an instrument had its origin in france, but it was first practically applied to photographing the sun in this country. as whatever observations were to be made would have to be done at governmental expense, an appropriation of two thousand dollars was obtained from congress for the expense of some preliminary instruments and investigations. admiral sands, superintendent of the observatory, now took an active part in the official preparations. it was suggested to him, on the part of the academy committee, that it would be well to join hands with other organizations, so as to have the whole affair carried on with unity and harmony. to this he assented. the result was a provision that these and all other preparations for observing the transit of venus should be made under the direction of a commission to be composed of the superintendent of the naval observatory, the superintendent of the united states coast survey, the president of the national academy of sciences, and two professors of mathematics attached to the naval observatory. under this provision the commission was constituted as follows: commodore b. f. sands, u. s. n., professor benjamin peirce, professor joseph henry, professor simon newcomb, professor william harkness. the academy committee now surrendered its functions to the commission, and the preparations were left entirely in the hands of the latter. so far as scientific operations were concerned, the views of the commission were harmonious through the whole of their deliberations. it was agreed from the beginning that the photographic method offered the greatest promise of success. but how, with what sort of instruments, and on what plan, must the photographs be taken? europeans had already begun to consider this question, and for the most part had decided on using photographic telescopes having no distinctive feature specially designed for the transit. in fact, one might almost say that the usual observations with the eye were to be made on the photograph instead of on the actual sun. the american commissioners were of opinion that this would lead to nothing but failure, and that some new system must be devised. the result was a series of experiments and trials with professor winlock's instrument at the cambridge observatory. the outcome of the matter was the adoption of his plan, with three most important additions, which i shall mention, because they may possibly yet be adopted with success in other branches of exact astronomy if this telescope is used, as it seems likely it may be. the first feature was that the photographic telescope should be mounted exactly in the meridian, and that its direction should be tested by having the transit instrument mounted in front of it, in the same line with it. in this way the axis of the telescope was a horizontal north and south line. the next feature was that, immediately in front of the photographic plate, in fact as nearly in contact with it as possible without touching it, a plumb line of which the thread was a very fine silver wire should be suspended, the bob of which passed down below, and was immersed in a vessel of water to prevent vibration. in this way the direction of the north and south line on the plate admitted of being calculated with the greatest exactness, and the plumb line being photographed across the disk of the sun, the position angle could be measured with the same precision that any other measure could be made. the third feature was that the distance between the photographic plate and the object glass of the telescope should be measured by a long iron rod which was kept in position above the line of sight of the telescope itself. this afforded the means of determining to what angle a given measure on the plate would correspond. the whole arrangement would enable the position of the centre of venus with respect to the centre of the sun to be determined by purely geometric methods. one reason for relying entirely on this was that the diameter of the sun, as photographed, would be greater the greater the intensity of the photographic impression, so that no reliance could be placed upon its uniformity. ours were the only parties whose photographic apparatus was fitted up in this way. the french used a similar system, but without the essentials of the plumb line and the measurement of the length of the telescope. the english and germans used ordinary telescopes for the purpose. one of the earliest works of the commission was the preparation and publication of several papers, which were published under the general title, "papers relating to the transit of venus in 1874." the first of these papers was a discussion of our proposed plan of photographing, in which the difficulties of the problem, and the best way of surmounting them, were set forth. the next, called part ii., related to the circumstances of the transit, and was therefore entirely technical. part iii. related to the corrections of hansen's table of the moon, and was published as a paper relating to the transit of venus, because these corrections were essential in determining the longitudes of the stations by observations of the moon. in england the preparations were left mostly in the hands of professor airy, astronomer royal, and, i believe, captain tupman, who at least took a leading part in the observations and their subsequent reduction. in france, germany, and russia, commissions were appointed to take charge of the work and plan the observations. as coöperation among the parties from different countries would be generally helpful, i accepted an invitation to attend a meeting of the german commission, to be held at hanover in august, 1873. hansen was president of the commission, while auwers was its executive officer. one of my main objects was to point out the impossibility of obtaining any valuable result by the system of photographing which had been proposed, but i was informed, in reply, that the preparations had advanced too far to admit of starting on a new plan and putting it in operation. from the beginning of our preparations it began to be a question of getting from congress the large appropriations necessary for sending out the expeditions and fitting them up with instruments. the sum of $50,000 was wanted for instruments and outfit. hon. james a. garfield was then chairman of the committee on appropriations. his principles and methods of arranging appropriations for the government were, in some features, so different from those generally in vogue that it will be of interest to describe them. first of all, garfield was rigidly economical in grants of money. this characteristic of a chairman of a committee on appropriations was almost a necessary one. but he possessed it in a different way from any other chairman before or since. the method of the "watch dogs of the treasury" who sometimes held this position was to grant most of the objects asked for, but to cut down the estimated amounts by one fourth or one third. this was a very easy method, and one well fitted to impress the public, but it was one that the executive officers of the government found no difficulty in evading, by the very simple process of increasing their estimate so as to allow for the prospective reduction. [2] garfield compared this system to ordering cloth for a coat, but economizing by reducing the quantity put into it. if a new proposition came before him, the question was whether it was advisable for the government to entertain it at all. he had to be thoroughly convinced before this would be done. if the question was decided favorably all the funds necessary for the project were voted. when the proposition for the transit of venus came before him, he proceeded in a manner which i never heard of the chairman of an appropriation committee adopting before or since. instead of calling upon those who made the proposition to appear formally before the committee, he asked me to dinner with his family, where we could talk the matter over. one other guest was present, judge black of pennsylvania. he was a dyed-in-the-wool democrat, wielding as caustic a pen as was ever dipped into ink, but was, withal, a firm personal friend and admirer of garfield. as may readily be supposed, the transit of venus did not occupy much time at the table. i should not have been an enthusiastic advocate of the case against opposition, in any case, because my hopes of measuring the sun's distance satisfactorily by that method were not at all sanguine. my main interest lay in the fact that, apart from this, the transit would afford valuable astronomical data for the life work which i had mainly in view. so the main basis of my argument was that other nations were going to send out parties; that we should undoubtedly do the same, and that they must be equipped and organized in the best way. it appears that judge black was an absent-minded man, as any man engaged in thought on very great subjects, whether of science, jurisprudence, or politics, has the right to be. garfield asked him whether it was true that, on one occasion, when preparing an argument, and walking up and down the room, his hat chanced to drop on the floor at one end of the room, and was persistently used as a cuspidor until the argument was completed. mr. black neither affirmed nor denied the story, but told another which he said was true. while on his circuit as judge he had, on one occasion, tried a case of theft in which the principal evidence against the accused was the finding of the stolen article in his possession. he charged the jury that this fact was _prima facie_ evidence that the man was actually the thief. when through his business and about to leave for home, he went into a jeweler's shop to purchase some little trinket for his wife. the jeweler showed him a number of little articles, but finding none to suit him, he stepped into his carriage and drove off. in the course of the day he called on a street urchin to water his horse. reaching into his pocket for a reward, the first thing he got hold of was a diamond ring which must have been taken from the shop of the jeweler when he left that morning. "i wondered," said the judge, "how i should have come out had i been tried under my own law." the outcome of the matter was that the appropriations were duly made; first, in 1872, $50,000 for instruments, then, the year following, $100,000 for the expeditions. in 1874, $25,000 more was appropriated to complete the work and return the parties to their homes. the date of the great event was december 8-9, 1874. to have the parties thoroughly drilled in their work, they were brought together at washington in the preceding spring for practice and rehearsal. in order that the observations to be made by the eye should not be wholly new, an apparatus representing the transit was mounted on the top of winder's building, near the war department, about two thirds of a mile from the observatory. when this was observed through the telescope from the roof of the observatory, an artificial black venus was seen impinging upon an artificial sun, and entering upon its disk in the same way that the actual venus would be seen. this was observed over and over until, as was supposed, the observers had gotten into good practice. in order to insure the full understanding of the photographic apparatus, the instruments were mounted and the parties practiced setting them up and going through the processes of photographing the sun. to carry out this arrangement with success, it was advisable to have an expert in astronomical photography to take charge of the work. dr. henry draper of new york was invited for this purpose, and gave his services to the commission for several weeks. this transit was not visible in the united states. it did not begin until after the sun had set in san francisco, and it was over before the rising sun next morning had reached western europe. all the parties had therefore to be sent to the other side of the globe. three northern stations were occupied,--in china, japan, and siberia; and five southern ones, at various points on the islands of the pacific and indian oceans. this unequal division was suggested by the fact that the chances of fair weather were much less in the southern hemisphere than in the northern. the southern parties were taken to their destinations in the u. s. s. swatara, captain ralph chandler, u. s. n., commanding. in astronomical observations all work is at the mercy of the elements. clear weather was, of course, a necessity to success at any station. in the present case the weather was on the whole unpropitious. while there was not a complete failure at any one station, the number or value of the observations was more or less impaired at all. where the sky was nearly cloudless, the air was thick and hazy. this was especially the case at nagasaki and pekin, where from meteorological observations which the commission had collected through our consuls, the best of weather was confidently expected. what made this result more tantalizing was that the very pains we had taken to collect the data proved, by chance, to have made the choice worse. for some time it was deliberated whether the japanese station should be in nagasaki or yokohama. consultation with the best authorities and a study of the records showed that, while yokohama was a favorable spot, the chances were somewhat better at nagasaki. so to nagasaki the party was sent. but when the transit came, while the sky was of the best at yokohama, it was far from being so at nagasaki. something of the same sort occurred at the most stormy of all the southern stations, that at kerguelen island. the british expeditions had, in the beginning, selected a station on this island known as christmas harbor. we learned that a firm of new london, conn., had a whaling station on the island. it was therefore applied to to know what the weather chances were at various points in the island. information was obtained from their men, and it was thus found that molloy point, bad though the weather there was, afforded better chances than christmas harbor; so it was chosen. but this was not all; the british parties, either in consequence of the information we had acquired, or through what was learned from the voyage of the challenger, established their principal station near ours. but it happened that the day at christmas harbor was excellent, while the observations were greatly interfered with by passing clouds at molloy point. after the return of the parties sent out by the various nations, it did not take long for the astronomers to find that the result was disappointing, so far, at least, as the determination of the sun's distance was concerned. it became quite clear that this important element could be better measured by determining the velocity of light and the time which it took to reach us from the sun than it could by any transit of venus. it was therefore a question whether parties should be sent out to observe the transit of 1882. on this subject the astronomers of the country at large were consulted. as might have been expected, there was a large majority in favor of the proposition. the negative voices were only two in number, those of pickering and myself. i took the ground that we should make ample provisions for observing it at various stations in our own country, where it would now be visible, but that, in view of the certain failure to get a valuable result for the distance of the sun by this method, it was not worth while for us to send parties to distant parts of the world. i supposed the committee on appropriations might make careful inquiry into the subject before making the appropriation, but a representation of the case was all they asked for, and $10,000 was voted for improving the instruments and $75,000 for sending out parties. expeditions being thus decided upon, i volunteered to take charge of that to the cape of good hope. the scientific personnel of my party comprised an officer of the army engineers, one of the navy, and a photographer. the former were lieutenant thomas l. casey, jr., corps of engineers, u. s. a., and lieutenant j. h. l. holcombe, u. s. n. we took a cunard steamer for liverpool about the middle of september, 1882, and transported our instruments by rail to southampton, there to have them put on the cape steamship. at liverpool i was guilty of a remissness which might have caused much trouble. our apparatus and supplies, in a large number of boxes, were all gathered and piled in one place. i sent one of my assistants to the point to see that it was so collected that there should be no possibility of mistake in getting it into the freight car designed to carry it to southampton, but did not require him to stay there and see that all was put on board. when the cases reached southampton it was found that one was missing. it was one of the heaviest of the lot, containing the cast-iron pier on which the photoheliograph was to be mounted. while it was possible to replace this by something else, such a course would have been inconvenient and perhaps prejudicial. the steamer was about to sail, but would touch at plymouth next day. only one resource was possible. i telegraphed the mistake to liverpool and asked that the missing box be sent immediately by express to plymouth. we had the satisfaction of seeing it come on board with the mail just as the steamer was about to set sail. we touched first at madeira, and then at ascension island, the latter during the night. one of the odd things in nomenclature is that this island, a british naval station, was not called such officially, but was a "tender to her majesty's ship flora," i believe. it had become astronomically famous a few years before by gill's observations of the position of mars to determine the solar parallax. we touched six hours at st. helena, enough to see the place, but scarcely enough to make a visit to the residence of napoleon, even had we desired to see it. the little town is beautifully situated, and the rocks around are very imposing. my most vivid recollection is, however, of running down from the top of a rock some six hundred or eight hundred feet high, by a steep flight of steps, without stopping, or rather of the consequences of this imprudent gymnastic performance. i could scarcely move for the next three days. cape town was then suffering from an epidemic of smallpox, mostly confined to the malay population, but causing some disagreeable results to travelers. our line of ships did not terminate their voyage at the cape, but proceeded thence to other african ports east of the cape. here a rigid quarantine had been established, and it was necessary that the ships touching at the cape of good hope should have had no communication with the shore. thus it happened that we found, lying in the harbor, the ship of our line which had preceded us, waiting to get supplies from us, in order that it might proceed on its voyage. looking at a row-boat after we had cast anchor, we were delighted to see two faces which i well knew: those of david gill, astronomer of the cape observatory, and dr. w. l. elkin, now director of the yale observatory. the latter had gone to the cape as a volunteer observer with gill, their work being directed mostly to parallaxes of stars too far south to be well observed in our latitude. our friends were not, however, even allowed to approach the ship, for fear of the smallpox, the idea appearing to be that the latter might be communicated by a sort of electric conduction, if the boat and the ship were allowed to come into contact, so we had to be put ashore without their aid. we selected as our station the little town of wellington, some forty miles northeast of cape town. the weather chances were excellent anywhere, but here they were even better than at the cape. the most interesting feature of the place was what we might call an american young ladies' school. the dutch inhabitants of south africa are imbued with admiration of our institutions, and one of their dreams is said to be a united states of south africa modeled after our own republic. desiring to give their daughters the best education possible, they secured the services of miss ferguson, a well-known new england teacher, to found a school on the american model. we established our station in the grounds of this school. the sky on the day of the transit was simply perfect. notwithstanding the intensity of the sun's rays, the atmosphere was so steady that i have never seen the sun to better advantage. so all our observations were successful. on our departure we left two iron pillars, on which our apparatus for photographing the sun was mounted, firmly imbedded in the ground, as we had used them. whether they will remain there until the transit of 2004, i do not know, but cannot help entertaining a sentimental wish that, when the time of that transit arrives, the phenomenon will be observed from the same station, and the pillars be found in such a condition that they can again be used. all the governments, except our own, which observed the two transits of venus on a large scale long ago completed the work of reduction, and published the observations in full. on our own part we have published a preliminary discussion of some observations of the transit of 1874. of that of 1882 nothing has, i believe, been published except some brief statements of results of the photographs, which appeared in an annual report of the naval observatory. having need in my tables of the planets of the best value of the solar parallax that could be obtained by every method, i worked up all the observations of contacts made by the parties of every country, but, of course, did not publish our own observations. up to the present time, twenty-eight years after the first of the transits, and twenty years after the second, our observations have never been officially published except to the extent i have stated. the importance of the matter may be judged by the fact that the government expended $375,000 on these observations, not counting the salaries of its officers engaged in the work, or the cost of sailing a naval ship. as i was a member of the commission charged with the work, and must therefore bear my full share of the responsibility for this failure, i think it proper to state briefly how it happened, hoping thereby to enforce the urgent need of a better organization of some of our scientific work. the work of reducing such observations, editing and preparing them for the press, involved much computation to be done by assistants, and i, being secretary of the commission, was charged with the execution of this part of the work. the appropriations made by congress for the observations were considered available for the reduction also. there was a small balance left over, and i estimated that $3000 more would suffice to complete the work. this was obtained from congress in the winter of 1875. about the end of 1876 i was surprised to receive from the treasury department a notification that the appropriation for the transit of venus was almost exhausted, when according to my accounts, more than $3000 still remained. on inquiry it was found that the sum appropriated about two years before had never been placed to the credit of the transit of venus commission, having been, in fact, inserted in a different appropriation bill from that which contained the former grant. i, as secretary of the commission, made an application to the treasury department to have the sum, late though it was, placed to our credit. but the money had been expended and nothing could be now done in the matter. [3] the computers had therefore to be discharged and the work stopped until a new appropriation could be obtained from congress. during the session of 1876-77, $5000 was therefore asked for for the reduction of the observations. it was refused by the house committee on appropriations. i explained the matter to mr. julius h. seelye, formerly president of amherst college, who was serving a term in congress. he took much interest in the subject, and moved the insertion of the item when the appropriation bill came up before the house. mr. atkins, chairman of the appropriations committee, opposed the motion, maintaining that the navy department had under its orders plenty of officers who could do the work, so there was no need of employing the help of computers. but the house took a different view, and inserted the item over the heads of the appropriations committee. now difficulties incident to the divided responsibility of the commission were met with. during the interim between the death of admiral davis, in february, 1877, and the coming of admiral john rodgers as his successor, a legal question arose as to the power of the commission over its members. the work had to stop until it was settled, and i had to discharge my computers a second time. after it was again started i discovered that i did not have complete control of the funds appropriated for reducing the observations. the result was that the computers had to be discharged and the work stopped for the third time. this occurred not long before i started out to observe the transit in 1882. for me the third hair was the one that broke the camel's back. i turned the papers and work over to professor harkness, by whom the subject was continued until he was made astronomical director of the naval observatory in 1894. i do not know that the commission was ever formally dissolved. practically, however, its functions may be said to have terminated in the year 1886, when a provision of law was enacted by which all its property was turned over to the secretary of the navy. what the present condition of the work may be, and how much of it is ready for the press, i cannot say. my impression is that it is in that condition known in household language as "all done but finishing." whether it will ever appear is a question for the future. all the men who took part in it or who understood its details are either dead or on the retired list, and it is difficult for one not familiar with it from the beginning to carry it to completion. [1] for the incidents connected with the english observations of this transit, the author is indebted to vice-admiral w. h. smyth's curious and rare book, _speculum hartwellianum_, london, 1860. it and other works of the same author may be described as queer and interesting jumbles of astronomical and other information, thrown into an interesting form; and, in the case of the present work, spread through a finely illustrated quarto volume of nearly five hundred pages. [2] "the war department got ahead of us in the matter of furniture," said an officer of the navy department to me long afterwards, when the furniture for the new department building was being obtained. "they knew enough to ask for a third more than they wanted; we reduced our estimate to the lowest point. both estimates were reduced one third by the appropriations committee. the result is that they have all the furniture they want, while we are greatly pinched." [3] as this result would not be possible under our present system, which was introduced by the first cleveland administration, i might remark that it resulted from a practice on the part of the treasury of lumping appropriations on its books in order to simplify the keeping of the accounts. vii the lick observatory in the wonderful development of astronomical research in our country during the past twenty years, no feature is more remarkable than the rise on an isolated mountain in california of an institution which, within that brief period, has become one of the foremost observatories of the world. as everything connected with the early history of such an institution must be of interest, it may not be amiss if i devote a few pages to it. in 1874 the announcement reached the public eye that james lick, an eccentric and wealthy californian, had given his entire fortune to a board of trustees to be used for certain public purposes, one of which was the procuring of the greatest and most powerful telescope that had ever been made. there was nothing in the previous history of the donor that could explain his interest in a great telescope. i am sure he had never looked through a telescope in his life, and that if he had, and had been acquainted with the difficulties of an observation with it, it is quite likely the lick observatory would never have existed. from his point of view, as, indeed, from that of the public very generally, the question of telescopic vision is merely one of magnifying power. by making an instrument large and powerful enough we may hope even to discover rational beings on other planets. the president of the first board of trustees was mr. d. o. mills, the well-known capitalist, who had been president of the bank of california. mr. mills visited washington in the summer or autumn of 1874, and conferred with the astronomers there, among others myself, on the question of the proposed telescope. i do not think that an observatory properly so called was, at first, in mr. lick's mind; all he wanted was an immense telescope. the question was complicated by the result of some correspondence between mr. lick and the firm of alvan clark & sons. the latter had been approached to know the cost of constructing the desired telescope. without making any exact estimate, or deciding upon the size of the greatest telescope that could be constructed, they named a very large sum, $200,000 i believe, as the amount that could be put into the largest telescope it was possible to make. mr. lick deemed this estimate exorbitant, and refused to have anything more to do with the firm. the question now was whether any one else besides the clarks could make what was wanted. i suggested to mr. mills that this question was a difficult one to answer, as no european maker was known to rival the clerks in skill in the desired direction. it was impossible to learn what could be done in europe except by a personal visit to the great optical workshops and a few observatories where great telescopes had been mounted. i also suggested that a director of the new establishment should be chosen in advance of beginning active work, so that everything should be done under his supervision. as such director i suggested that very likely professor holden, then my assistant on the great equatorial, might be well qualified. at least i could not, at the moment, name any one i thought would be decidedly preferable to him. i suggested another man as possibly available, but remarked that he had been unfortunate. "i don't want to have anything to do with unfortunate men," was the reply. the necessity of choosing a director was not, however, evident, but communication was opened with professor holden as well as myself to an extent that i did not become aware of until long afterward. the outcome of mr. mills's visit was that in december, 1874, i was invited to visit the european workshops as an agent of the lick trustees, with a view of determining whether there was any chance of getting the telescope made abroad. the most difficult and delicate question arose in the beginning; shall the telescope be a reflector or a refractor? the largest and most powerful one that could be made would be, undoubtedly, a reflector. and yet reflecting telescopes had not, as a rule, been successful in permanent practical work. the world's work in astronomy was done mainly with refracting telescopes. this was not due to any inherent superiority in the latter, but to the mechanical difficulties incident to so supporting the great mirror of a reflecting telescope that it should retain its figure in all positions. assuming that the choice must fall upon a refractor, unless proper guarantees for one of the other kind should be offered, one of my first visits was to the glass firm of chance & co. in birmingham, who had cast the glass disks for the washington telescope. this firm and feil of paris were the only two successful makers of great optical disks in the world. chance & co. offered the best guarantees, while feil had more enthusiasm than capital, although his skill was of the highest. another paris firm was quite willing to undertake the completion of the telescope, but it was also evident that its price was suggested by the supposed liberality of an eccentric california millionaire. i returned their first proposal with the assurance that it would be useless to submit it. a second was still too high to offer any inducement over the american firm. besides, there was no guarantee of the skill necessary to success. in germany the case was still worse. the most renowned firm there, the successors of fraunhofer, were not anxious to undertake such a contract. the outcome of the matter was that howard grubb, of dublin, was the only man abroad with whom negotiations could be opened with any chance of success. he was evidently a genius who meant business. yet he had not produced a work which would justify unlimited confidence in his ability to meet mr. lick's requirements. the great vienna telescope which he afterward constructed was then only being projected. not long after my return with this not very encouraging report, mr. lick suddenly revoked his gift, through some dissatisfaction with the proceedings of his trustees, and appointed a new board to carry out his plans. this introduced legal complications, which were soon settled by a friendly suit on the part of the old trustees, asking authority to transfer their trust. the president of the new board was mr. richard s. floyd, a member of the well-known virginia family of that name, and a graduate, or at least a former cadet, of the united states naval academy. i received a visit from him on his first trip to the east in his official capacity, early in 1876, i believe. some correspondence with mr. lick's home representative ensued, of which the most interesting feature was the donor's idea of a telescope. he did not see why so elaborate and expensive a mounting as that proposed was necessary, and thought that the object glass might be mounted on the simplest kind of a pole or tower which would admit of its having the requisite motions in connection with the eyepiece. whether i succeeded in convincing him of the impracticability of his scheme, i do not know, as he died before the matter was settled. this left the trustees at liberty to build and organize the institution as they deemed best. it was speedily determined that the object glass should be shaped by the clarks, who should also be responsible for getting the rough disks. this proved to be a very difficult task. chance & co. were unwilling to undertake the work and feil had gone out of business, leaving the manufacture in the hands of his son. the latter also failed, and the father had to return. ultimately the establishment was purchased by mantois, whose success was remarkable. he soon showed himself able to make disks not only of much larger size than had ever before been produced, but of a purity and transparency which none before him had ever approached. he died in 1899 or 1900, and it is to be hoped that his successor will prove to be his equal. the original plan of mr. lick had been to found the observatory on the borders of lake tahoe, but he grew dissatisfied with this site and, shortly before his death, made provisional arrangements for placing it on mount hamilton. in 1879 preparations had so far advanced that it became necessary to decide whether this was really a suitable location. i had grave doubts on the subject. a mountain side is liable to be heated by the rays of the sun during the day, and a current of warm air which would be fatal to the delicacy of astronomical vision is liable to rise up the sides and envelope the top of the mountain. i had even been informed that, on a summer evening, a piece of paper let loose on the mountain top would be carried up into the air by the current. but, after all, the proof of the pudding is in the eating, and holden united with me in advising that an experienced astronomer with a telescope should be stationed for a few weeks on the mountain in order to determine, by actual trial, what the conditions of seeing were. the one best man for this duty was s. w. burnham of chicago, who had already attained a high position in the astronomical world by the remarkable skill shown in his observations of double stars. so, in august, 1879, huts were built on the mountain, and burnham was transported thither with his telescope. i followed personally in september. we passed three nights on the mountain with captain floyd, studying the skies by night and prospecting around in the daytime to see whether the mountain top or some point in the neighboring plateau offered the best location for the observatory. so far as the atmospheric conditions were concerned, the results were beyond our most sanguine expectations. what the astronomer wants is not merely a transparent atmosphere, but one of such steadiness that the image of a star, as seen in a telescope, may not be disturbed by movements of the air which are invisible to the naked eye. burnham found that there were forty-two first-class nights during his stay, and only seven which would be classed as low as medium. in the east the number of nights which he would call first-class are but few in a year, and even the medium night is by no means to be counted on. no further doubt could remain that the top of the mountain was one of the finest locations in the world for an astronomical observatory, and it was definitely selected without further delay. sometime after my return mr. floyd sent me a topographical sketch of the mountain, with a request to prepare preliminary plans for the observatory. as i had always looked on professor holden as probably the coming director, i took him into consultation, and the plans were made under our joint direction in my office. the position and general arrangement of the buildings remain, so far as i am aware, much as then planned; the principal change being the omission of a long colonnade extending over the whole length of the main front in order to secure an artistic and imposing aspect from the direction of san josé. in the summer of 1885, as i was in new york in order to sail next day to europe, i was surprised by a visit from judge hagar, a prominent citizen of san francisco, a member of the board of regents of the university of california, and an active politician, who soon afterward became collector of the port, to consult me on the question of choosing professor holden as president of the university. this was not to interfere with his becoming director of the lick observatory whenever that institution should be organized, but was simply a temporary arrangement to bridge over a difficulty. in the autumn of 1887 i received an invitation from mr. floyd to go with him to cleveland, in order to inspect the telescope, which was now nearly ready for delivery. it was mounted in the year following, and then holden stepped from the presidency of the university into the directorship of the observatory. the institution made its mark almost from the beginning. i know of no example in the world in which young men, most of whom were beginners, attained such success as did those whom holden collected around him. the names of barnard, campbell, and schaeberle immediately became well known in astronomy, owing to the excellence of their work. burnham was, of course, no beginner, being already well known, nor was keeler, who was also on the staff. in a few years commenced the epoch-making work of campbell, in the most refined and difficult problem of observational astronomy,--that of the measurement of the motion of stars to or from us. through the application of photography and minute attention to details, this work of the lick observatory almost immediately gained a position of preëminence, which it maintains to the present time. if any rival is to appear, it will probably be the yerkes observatory. the friendly competition which we are likely to see between these two establishments affords an excellent example of the spirit of the astronomy of the future. notwithstanding their rivalry, each has done and will do all it can to promote the work of the other. the smiles of fortune have been bestowed even upon efforts that seemed most unpromising. after work was well organized, mr. crossley, of england, presented the observatory with a reflecting telescope of large size, but which had never gained a commanding reputation. no member of the staff at first seemed ambitious to get hold of such an instrument, but, in time, keeler gave it a trial in photographing nebulæ. then it was found that a new field lay open. the newly acquired reflector proved far superior to other instruments for this purpose, the photographic plates showing countless nebulæ in every part of the sky, which the human eye was incapable of discerning in the most powerful of telescopes. in 1892, only four years after the mounting of the telescope, came the surprising announcement that the work of galileo on jupiter had been continued by the discovery of a fifth satellite to that planet. this is the most difficult object in the solar system, only one or two observers besides barnard having commanded the means of seeing it. the incident of my first acquaintance with the discoverer is not flattering to my pride, but may be worth recalling. in 1877 i was president of the american association for the advancement of science at the meeting held in nashville. there i was told of a young man a little over twenty years of age, a photographer by profession, who was interested in astronomy, and who desired to see me. i was, of course, very glad to make his acquaintance. i found that with his scanty earnings he had managed either to purchase or to get together the materials for making a small telescope. he was desirous of doing something with it that might be useful in astronomy, and wished to know what suggestions i could make in that line. i did not for a moment suppose that there was a reasonable probability of the young man doing anything better than amuse himself. at the same time, feeling it a duty to encourage him, i suggested that there was only one thing open to an astronomical observer situated as he was, and that was the discovery of comets. i had never even looked for a comet myself, and knew little about the methods of exploring the heavens for one, except what had been told me by h. p. tuttle. but i gave him the best directions i could, and we parted. it is now rather humiliating that i did not inquire more thoroughly into the case. it would have taken more prescience than i was gifted with to expect that i should live to see the bashful youth awarded the gold medal of the royal astronomical society for his work. the term of holden's administration extended through some ten years. to me its most singular feature was the constantly growing unpopularity of the director. i call it singular because, if we confine ourselves to the record, it would be difficult to assign any obvious reason for it. one fact is indisputable, and that is the wonderful success of the director in selecting young men who were to make the institution famous by their abilities and industry. if the highest problem of administration is to select the right men, the new director certainly mastered it. so far as liberty of research and publication went, the administration had the appearance of being liberal in the extreme. doubtless there was another side to the question. nothing happens spontaneously, and the singular phenomenon of one who had done all this becoming a much hated man must have an adequate cause. i have several times, from pure curiosity, inquired about the matter of well-informed men. on one occasion an instance of maladroitness was cited in reply. "true," said i, "it was not exactly the thing to do, but, after all, that is an exceedingly small matter." "yes," was the answer, "that was a small thing, but put a thousand small things like that together, and you have a big thing." a powerful factor in the case may have been his proceeding, within a year of his appointment, to file an astounding claim for the sum of $12,000 on account of services rendered to the observatory in the capacity of general adviser before his appointment as director. these services extended from the beginning of preparations in 1874 up to the completion of the work. the trustees in replying to the claim maintained that i had been their principal adviser in preparing the plans. however true this may have been, it was quite evident, from holden's statement, that they had been consulting him on a much larger scale than i had been aware of. this, however, was none of my concern. i ventured to express the opinion that the movement was made merely to place on record a statement of the director's services; and that no serious intention of forcing the matter to a legal decision was entertained. this surmise proved to be correct, as nothing more was heard of the claim. much has been said of the effect of the comparative isolation of such a community, which is apt to be provocative of internal dissension. but this cause has not operated in the case of holden's successors. keeler became the second director in 1897, and administered his office with, so far as i know, universal satisfaction till his lamented death in 1900. it would not be a gross overstatement to say that his successor was named by the practically unanimous voice of a number of the leading astronomers of the world who were consulted on the subject, and who cannot but be pleased to see how completely their advice has been justified by the result of campbell's administration. viii the author's scientific work perhaps an apology is due to the reader for my venturing to devote a chapter to my own efforts in the scientific line. if so, i scarcely know what apology to make, unless it is that one naturally feels interested in matters relating to his own work, and hopes to share that interest with his readers, and that it is easier for one to write such an account for himself than for any one else to do it for him. having determined to devote my life to the prosecution of exact astronomy, the first important problem which i took up, while at cambridge, was that of the zone of minor planets, frequently called asteroids, revolving between the orbits of mars and jupiter. it was formerly supposed that these small bodies might be fragments of a large planet which had been shattered by a collision or explosion. if such were the case, the orbits would, for a time at least, all pass through the point at which the explosion occurred. when only three or four were known, it was supposed that they did pass nearly through the same point. when this was found not to be the case, the theory of an explosion was in no way weakened, because, owing to the gradual changes in the form and position of the orbits, produced by the attraction of the larger planets, these orbits would all move away from the point of intersection, and, in the course of thousands of years, be so mixed up that no connection could be seen between them. this result was that nothing could be said upon the subject except that, if the catastrophe ever did occur, it must have been many thousand years ago. the fact did not in any way militate against the theory because, in view of the age of the universe, the explosion might as well have occurred hundreds of thousands or even millions of years ago as yesterday. to settle the question, general formulæ must be found by which the positions of these orbits could be determined at any time in the past, even hundreds of thousands of years back. the general methods of doing this were known, but no one had applied them to the especial case of these little planets. here, then, was an opportunity of tracing back the changes in these orbits through thousands of centuries in order to find whether, at a certain epoch in the past, so great a cataclysm had occurred as the explosion of a world. were such the case, it would be possible almost to set the day of the occurrence. how great a feat would it be to bring such an event at such a time to light! i soon found that the problem, in the form in which it had been attacked by previous mathematicians, involved no serious difficulty. at the springfield meeting of the american association for the advancement of science, in 1859, i read a paper explaining the method, and showed by a curve on the blackboard the changes in the orbit of one of the asteroids for a period, i think, of several hundred thousand years,--"beyond the memory of the oldest inhabitants"--said one of the local newspapers. a month later it was extended to three other asteroids, and the result published in the "astronomical journal." in the following spring, 1860, the final results of the completed work were communicated to the american academy of arts and sciences in a paper "on the secular variations and mutual relations of the orbits of the asteroids." the question of the possible variations in the orbits and the various relations amongst them were here fully discussed. one conclusion was that, so far as our present theory could show, the orbits had never passed through any common point of intersection. the whole trend of thought and research since that time has been toward the conclusion that no such cataclysm as that looked for ever occurred, and that the group of small planets has been composed of separate bodies since the solar system came into existence. it was, of course, a great disappointment not to discover the cataclysm, but next best to finding a thing is showing that it is not there. this, it may be remarked, was the first of my papers to attract especial notice in foreign scientific journals, though i had already published several short notes on various subjects in the "astronomical journal." at this point i may say something of the problems of mathematical astronomy in the middle of the last century. it is well known that we shall at least come very near the truth when we say that the planets revolve around the sun, and the satellites around their primaries according to the law of gravitation. we may regard all these bodies as projected into space, and thus moving according to laws similar to that which governs the motion of a stone thrown from the hand. if two bodies alone were concerned, say the sun and a planet, the orbit of the lesser around the greater would be an ellipse, which would never change its form, size, or position. that the orbits of the planets and asteroids do change, and that they are not exact ellipses, is due to their attraction upon each other. the question is, do these mutual attractions completely explain all the motions down to the last degree of refinement? does any world move otherwise than as it is attracted by other worlds? two different lines of research must be brought to bear on the question thus presented. we must first know by the most exact and refined observations that the astronomer can make exactly how a heavenly body does move. its position, or, as we cannot directly measure distance, its direction from us, must be determined as precisely as possible from time to time. its course has been mapped out for it in advance by tables which are published in the "astronomical ephemeris," and we may express its position by its deviation from these tables. then comes in the mathematical problem how it ought to move under the attraction of all other heavenly bodies that can influence its motion. the results must then be compared, in order to see to what conclusion we may be led. this mathematical side of the question is of a complexity beyond the powers of ordinary conception. i well remember that when, familiar only with equations of algebra, i first looked into a book on mechanics, i was struck by the complexity of the formulæ. but this was nothing to what one finds when he looks into a work on celestial mechanics, where a single formula may fill a whole chapter. the great difficulty arises from the fact that the constant action upon a planet exerted at every moment of time through days and years by another planet affects its motion in all subsequent time. the action of jupiter upon our earth this morning changes its motion forever, just as a touch upon a ball thrown by a pitcher will change the direction of the ball through its whole flight. the wondrous perfection of mathematical research is shown by the fact that we can now add up, as it were, all these momentary effects through years and centuries, with a view of determining the combined result at any one moment. it is true that this can be done only in an imperfect way, and at the expense of enormous labor; but, by putting more and more work into it, investigating deeper and deeper, taking into account smaller and smaller terms of our formulæ, and searching for the minutest effects, we may gradually approach, though we may never reach, absolute exactness. here we see the first difficulty in reaching a definite conclusion. one cannot be quite sure that a deviation is not due to some imperfection in mathematical method until he and his fellows have exhausted the subject so thoroughly as to show that no error is possible. this is hard indeed to do. taking up the question on the observational side, a source of difficulty and confusion at once presented itself. the motions of a heavenly body from day to day and year to year are mapped out by comparative observations on it and on the stars. the question of the exact positions of the stars thus comes in. in determining these positions with the highest degree of precision, a great variety of data have to be used. the astronomer cannot reach a result by a single step, nor by a hundred steps. he is like a sculptor chiseling all the time, trying to get nearer and nearer the ideal form of his statue, and finding that with every new feature he chisels out, a defect is brought to light in other features. the astronomer, when he aims at the highest mathematical precision in his results, finds nature warring with him at every step, just as if she wanted to make his task as difficult as possible. she alters his personal equation when he gets tired, makes him see a small star differently from a bright one, gives his instrument minute twists with heat and cold, sends currents of warm or cold air over his locality, which refract the rays of light, asks him to keep the temperature in which he works the same as that outside, in order to avoid refraction when the air enters his observing room, and still will not let him do it, because the walls and everything inside the room, being warmed up during the day, make the air warmer than it is outside. with all these obstacles which she throws in his way he must simply fight the best he can, exerting untiring industry to eliminate their effects by repeated observations under a variety of conditions. a necessary conclusion from all this is that the work of all observing astronomers, so far as it could be used, must be combined into a single whole. but here again difficulties are met at every step. there has been, in times past, little or no concert of action among astronomers at different observatories. the astronomers of each nation, perhaps of each observatory, to a large extent, have gone to work in their own way, using discordant data, perhaps not always rigidly consistent, even in the data used in a single establishment. how combine all the astronomical observations, found scattered through hundreds of volumes, into a homogeneous whole? what is the value of such an attempt? certainly if we measure value by the actual expenditure of nations and institutions upon the work, it must be very great. every civilized nation expends a large annual sum on a national observatory, while a still greater number of such institutions are supported at corporate expense. considering that the highest value can be derived from their labors only by such a combination as i have described, we may say the result is worth an important fraction of what all the observatories of the world have cost during the past century. such was, in a general way, the great problem of exact astronomy forty or fifty years ago. its solution required extended coöperation, and i do not wish to give the impression that i at once attacked it, or even considered it as a whole. i could only determine to do my part in carrying forward the work associated with it. perhaps the most interesting and important branch of the problem concerned the motion of the moon. this had been, ever since the foundation of the greenwich observatory, in 1670, a specialty of that institution. it is a curious fact, however, that while that observatory supplied all the observations of the moon, the investigations based upon these observations were made almost entirely by foreigners, who also constructed the tables by which the moon's motion was mapped out in advance. the most perfect tables made were those of hansen, the greatest master of mathematical astronomy during the middle of the century, whose tables of the moon were published by the british government in 1857. they were based on a few of the greenwich observations from 1750 to 1850. the period began with 1750, because that was the earliest at which observations of any exactness were made. only a few observations were used, because hansen, with the limited computing force at his command,--only a single assistant, i believe,--was not able to utilize a great number of the observations. the rapid motion of the moon, a circuit being completed in less than a month, made numerous observations necessary, while the very large deviations in the motion produced by the attraction of the sun made the problem of the mathematical theory of that motion the most complicated in astronomy. thus it happened that, when i commenced work at the naval observatory in 1861, the question whether the moon exactly followed the course laid out for her by hansen's tables was becoming of great importance. the same question arose in the case of the planets. so from a survey of the whole field, i made observations of the sun, moon, and planets my specialty at the observatory. if the astronomical reader has before him the volume of observations for 1861, he will, by looking at pages 366-440, be able to infer with nearly astronomical precision the date when i reported for duty. for a year or two our observations showed that the moon seemed to be falling a little behind her predicted motion. but this soon ceased, and she gradually forged ahead in a much more remarkable way. in five or six years it was evident that this was becoming permanent; she was a little farther ahead every year. what could it mean? to consider this question, i may add a word to what i have already said on the subject. in comparing the observed and predicted motion of the moon, mathematicians and astronomers, beginning with laplace, have been perplexed by what are called "inequalities of long period." for a number of years, perhaps half a century, the moon would seem to be running ahead, and then she would gradually relax her speed and fall behind. laplace suggested possible causes, but could not prove them. hansen, it was supposed, had straightened out the tangle by showing that the action of venus produced a swinging of this sort in the moon; for one hundred and thirty years she would be running ahead and then for one hundred and thirty years more falling back again, like a pendulum. two motions of this sort were combined together. they were claimed to explain the whole difficulty. the moon, having followed hansen's theory for one hundred years, would not be likely to deviate from it. now, it was deviating. what could it mean? taking it for granted, on hansen's authority, that his tables represented the motions of the moon perfectly since 1750, was there no possibility of learning anything from observations before that date? as i have already said, the published observations with the usual instruments were not of that refined character which would decide a question like this. but there is another class of observations which might possibly be available for the purpose. millions of stars, visible with large telescopes, are scattered over the heavens; tens of thousands are bright enough to be seen with small instruments, and several thousand are visible to any ordinary eye. the moon, in her monthly course around the heavens, often passes over a star, and of course hides it from view during the time required for the passage. the great majority of stars are so small that their light is obscured by the effulgence of the moon as the latter approaches them. but quite frequently the star passed over is so bright that the exact moment when the moon reaches it can be observed with the utmost precision. the star then disappears from view in an instant, as if its light were suddenly and absolutely extinguished. this is called an occultation. if the moment at which the disappearance takes place is observed, we know that at that instant the apparent angle between the centre of the moon and the star is equal to the moon's semi-diameter. by the aid of a number of such observations, the path of the moon in the heavens, and the time at which she arrives at each point of the path, can be determined. in order that the determination may be of sufficient scientific precision, the time of the occultation must be known within one or two seconds; otherwise, we shall be in doubt how much of the discrepancy may be due to the error of the observation, and how much to the error of the tables. occultations of some bright stars, such as aldebaran and antares, can be observed by the naked eye; and yet more easily can those of the planets be seen. it is therefore a curious historic fact that there is no certain record of an actual observation of this sort having been made until after the commencement of the seventeenth century. even then the observations were of little or no use, because astronomers could not determine their time with sufficient precision. it was not till after the middle of the century, when the telescope had been made part of astronomical instruments for finding the altitude of a heavenly body, and after the pendulum clock had been invented by huyghens, that the time of an occultation could be fixed with the required exactness. thus it happens that from 1640 to 1670 somewhat coarse observations of the kind are available, and after the latter epoch those made by the french astronomers become almost equal to the modern ones in precision. the question that occurred to me was: is it not possible that such observations were made by astronomers long before 1750? searching the published memoirs of the french academy of sciences and the philosophical transactions, i found that a few such observations were actually made between 1660 and 1700. i computed and reduced a few of them, finding with surprise that hansen's tables were evidently much in error at that time. but neither the cause, amount, or nature of the error could be well determined without more observations than these. was it not possible that these astronomers had made more than they published? the hope that material of this sort existed was encouraged by the discovery at the pulkowa observatory of an old manuscript by the french astronomer delisle, containing some observations of this kind. i therefore planned a thorough search of the old records in europe to see what could be learned. the execution of this plan was facilitated by the occurrence, in december, 1870, of an eclipse of the sun in spain and along the mediterranean. a number of parties were going out from this country to observe it, two of which were fitted out at the naval observatory. i was placed in charge of one of these, consisting, practically, of myself. the results of my observation would be of importance in the question of the moon's motion, but, although the eclipse was ostensibly the main object, the proposed search of the records was what i really had most in view. in paris was to be found the most promising mine; but the franco-prussian war was then going on, and i had to wait for its termination. then i made a visit to paris, which will be described in a later chapter. at the observatory the old records i wished to consult were placed at my disposal, with full liberty not only to copy, but to publish anything of value i could find in them. the mine proved rich beyond the most sanguine expectation. after a little prospecting, i found that the very observations i wanted had been made in great numbers by the paris astronomers, both at the observatory and at other points in the city. and how, the reader may ask, did it happen that these observations were not published by the astronomers who made them? why should they have lain unused and forgotten for two hundred years? the answer to these questions is made plain enough by an examination of the records. the astronomers had no idea of the possible usefulness and value of what they were recording. so far as we can infer from their work, they made the observations merely because an occultation was an interesting thing to see; and they were men of sufficient scientific experience and training to have acquired the excellent habit of noting the time at which a phenomenon was observed. but they were generally satisfied with simply putting down the clock time. how they could have expected their successors to make any use of such a record, or whether they had any expectations on the subject, we cannot say with confidence. it will be readily understood that no clocks of the present time (much less those of two hundred years ago) run with such precision that the moment read from the clock is exact within one or two seconds. the modern astronomer does not pretend to keep his clock correct within less than a minute; he determines by observation how far it is wrong, on each date of observation, and adds so much to the time given by the clock, or subtracts it, as the case may be, in order to get the correct moment of true time. in the case of the french astronomers, the clock would frequently be fifteen minutes or more in error, for the reason that they used apparent time, instead of mean time as we do. thus when, as was often the case, the only record found was that, at a certain hour, minute, and second, by a certain clock, _une étoile se cache par la lune_, a number of very difficult problems were presented to the astronomer who was to make use of the observations two centuries afterward. first of all, he must find out what the error of the clock was at the designated hour, minute, and second; and for this purpose he must reduce the observations made by the observer in order to determine the error. but it was very clear that the observer did not expect any successor to take this trouble, and therefore did not supply him with any facilities for so doing. he did not even describe the particular instrument with which the observations were made, but only wrote down certain figures and symbols, of a more or less hieroglyphic character. it needed much comparison and examination to find out what sort of an instrument was used, how the observations were made, and how they should be utilized for the required purpose. generally the star which the moon hid was mentioned, but not in all cases. if it was not, the identification of the star was a puzzling problem. the only way to proceed was to calculate the apparent position of the centre of the moon as seen by an observer at the paris observatory, at the particular hour and minute of the observation. a star map was then taken; the points of a pair of dividers were separated by the length of the moon's radius, as it would appear on the scale of the map; one point of the dividers was put into the position of the moon's centre on the map, and with the other a circle was drawn. this circle represented the outline of the moon, as it appeared to the observer at the paris observatory, at the hour and minute in question, on a certain day in the seventeenth century. the star should be found very near the circumference of the circle, and in nearly all cases a star was there. of course all this could not be done on the spot. what had to be done was to find the observations, study their relations and the method of making them, and copy everything that seemed necessary for working them up. this took some six weeks, but the material i carried away proved the greatest find i ever made. three or four years were spent in making all the calculations i have described. then it was found that seventy-five years were added, at a single step, to the period during which the history of the moon's motion could be written. previously this history was supposed to commence with the observations of bradley, at greenwich, about 1750; now it was extended back to 1675, and with a less degree of accuracy thirty years farther still. hansen's tables were found to deviate from the truth, in 1675 and subsequent years, to a surprising extent; but the cause of the deviation is not entirely unfolded even now. during the time i was doing this work, paris was under the reign of the commune and besieged by the national forces. the studies had to be made within hearing of the besieging guns; and i could sometimes go to a window and see flashes of artillery from one of the fortifications to the south. nearly every day i took a walk through the town, occasionally as far as the arc. as my observations during these walks have no scientific value, i shall postpone an account of what i saw to another chapter. one curious result of this work is that the longitude of the moon may now be said to be known with greater accuracy through the last quarter of the seventeenth century than during the ninety years from 1750 to 1840. the reason is that, for this more modern period, no effective comparison has been made between observations and hansen's tables. just as this work was approaching completion i was called upon to decide a question which would materially influence all my future activity. the lamented death of professor winlock in 1875 left vacant the directorship of the harvard observatory. a month or two later i was quite taken by surprise to receive a letter from president eliot tendering me this position. i thus had to choose between two courses. one led immediately to a professorship in harvard university, with all the distinction and worldly advantages associated with it, including complete freedom of action, an independent position, and the opportunity of doing such work as i deemed best with the limited resources at the disposal of the observatory. on the other hand was a position to which the official world attached no importance, and which brought with it no worldly advantages whatever. i first consulted mr. secretary robeson on the matter. the force with which he expressed himself took me quite by surprise. "by all means accept the place; don't remain in the government service a day longer than you have to. a scientific man here has no future before him, and the quicker he can get away the better." then he began to descant on our miserable "politics" which brought about such a state of things. such words, coming from a sagacious head of a department who, one might suppose, would have been sorry to part with a coadjutor of sufficient importance to be needed by harvard university, seemed to me very suggestive. and yet i finally declined the place, perhaps unwisely for myself, though no one who knows what the cambridge observatory has become under professor pickering can feel that harvard has any cause to regret my decision. an apology for it on my own behalf will seem more appropriate. on the cambridge side it must be remembered that the harvard observatory was then almost nothing compared with what it is now. it was poor in means, meagre in instrumental outfit, and wanting in working assistants; i think the latter did not number more than three or four, with perhaps a few other temporary employees. there seemed little prospect of doing much. on the washington side was the fact that i was bound to washington by family ties, and that, if harvard needed my services, surely the government needed them much more. true, this argument was, for the time, annulled by the energetic assurance of secretary robeson, showing that the government felt no want of any one in its service able to command a university professorship. but i was still pervaded by the optimism of youth in everything that concerned the future of our government, and did not believe that, with the growth of intelligence in our country, an absence of touch between the scientific and literary classes on the one side, and "politics" on the other, could continue. in addition to this was the general feeling by which i have been actuated from youth--that one ought to choose that line of activity for which nature had best fitted him, trusting that the operation of moral causes would, in the end, right every wrong, rather than look out for place and preferment. i felt that the conduct of government astronomy was that line of activity for which i was best fitted, and that, in the absence of strong reason to the contrary, it had better not be changed. in addition to these general considerations was the special point that, in the course of a couple of years, the directorship of the nautical almanac would become vacant, and here would be an unequaled opportunity for carrying on the work in mathematical astronomy i had most at heart. yet, could i have foreseen that the want of touch which i have already referred to would not be cured, that i should be unable to complete the work i had mapped out before my retirement, or to secure active public interest in its continuance, my decision would perhaps have been different. on september 15, 1877, i took charge of the nautical almanac office. the change was one of the happiest of my life. i was now in a position of recognized responsibility, where my recommendations met with the respect due to that responsibility, where i could make plans with the assurance of being able to carry them out, and where the countless annoyances of being looked upon as an important factor in work where there was no chance of my being such would no longer exist. practically i had complete control of the work of the office, and was thus, metaphorically speaking, able to work with untied hands. it may seem almost puerile to say this to men of business experience, but there is a current notion, spread among all classes, that because the naval observatory has able and learned professors, therefore they must be able to do good and satisfactory work, which may be worth correcting. i found my new office in a rather dilapidated old dwelling-house, about half a mile or less from the observatory, in one of those doubtful regions on the border line between a slum and the lowest order of respectability. if i remember aright, the only occupants of the place were the superintendent, my old friend mr. loomis, senior assistant, who looked after current business, a proof-reader and a messenger. all the computers, including even one copyist, did their work at their homes. a couple of changes had to be made in the interest of efficiency. the view taken of one of these may not only interest the reader, but give him an idea of what people used to think of government service before the era of civil service reform. the proof-reader was excellent in every respect except that of ability to perform his duty. he occupied a high position, i believe, in the grand army of the republic, and thus wielded a good deal of influence. when his case was appealed to the secretary of the navy, apellant was referred to me. i stated the trouble to counsel,--he did not appear to see figures, or be able to distinguish whether they were right or wrong, and therefore was useless as a proof-reader. "it is not his fault," was the reply; "he nearly lost his eyesight in the civil war, and it is hard for him to see at all." in the view of counsel that explanation ought to have settled the case in his favor. it did not, however, but "influence" had no difficulty in making itself more successful in another field. among my first steps was that of getting a new office in the top of the corcoran building, then just completed. it was large and roomy enough to allow quite a number of assistants around me. much of the work was then, as now, done by the piece, or annual job, the computers on it very generally working at their homes. this offers many advantages for such work; the government is not burdened with an officer who must be paid his regular monthly salary whether he supplies his work or not, and whom it is unpleasant and difficult to get rid of in case of sickness or breakdown of any sort. the work is paid for when furnished, and the main trouble of administration saved. it is only necessary to have a brief report from time to time, showing that the work is actually going on. i began with a careful examination of the relation of prices to work, making an estimate of the time probably necessary to do each job. among the performers of the annual work were several able and eminent professors at various universities and schools. i found that they were being paid at pretty high professional prices. i recall with great satisfaction that i was able to reduce the prices and, step by step, concentrate all the work in washington, without detriment to the pleasant relations i sustained with these men, some of them old and intimate friends. these economies went on increasing year by year, and every dollar that was saved went into the work of making the tables necessary for the future use of the ephemeris. the programme of work which i mapped out, involved, as one branch of it, a discussion of all the observations of value on the positions of the sun, moon, and planets, and incidentally, on the bright fixed stars, made at the leading observatories of the world since 1750. one might almost say it involved repeating, in a space of ten or fifteen years, an important part of the world's work in astronomy for more than a century past. of course, this was impossible to carry out in all its completeness. in most cases what i was obliged practically to confine myself to was a correction of the reductions already made and published. still, the job was one with which i do not think any astronomical one ever before attempted by a single person could compare in extent. the number of meridian observations on the sun, mercury, venus, and mars alone numbered 62,030. they were made at the observatories of greenwich, paris, königsberg, pulkowa, cape of good hope,--but i need not go over the entire list, which numbers thirteen. the other branches of the work were such as i have already described,--the computation of the formulæ for the perturbation of the various planets by each other. as i am writing for the general reader, i need not go into any further technical description of this work than i have already done. something about my assistants may, however, be of interest. they were too numerous to be all recalled individually. in fact, when the work was at its height, the office was, in the number of its scientific employees, nearly on an equality with the three or four greatest observatories of the world. one of my experiences has affected my judgment on the general morale of the educated young men of our country. in not a single case did i ever have an assistant who tried to shirk his duty to the government, nor do i think there was more than a single case in which one tried to contest my judgment of his own merits, or those of his work. i adopted the principle that promotion should be by merit rather than by seniority, and my decisions on that matter were always accepted without complaint. i recall two men who voluntarily resigned when they found that, through failure of health or strength, they were unable to properly go on with their work. in frankness i must admit that there was one case in which i had a very disagreeable contest in getting rid of a learned gentleman whose practical powers were so far inferior to his theoretical knowledge that he was almost useless in the office. he made the fiercest and most determined fight in which i was ever engaged, but i must, in justice to all concerned, say that his defect was not in will to do his work but in the requisite power. officially i was not without fault, because, in the press of matters requiring my attention, i had entrusted too much to him, and did not discover his deficiencies until some mischief had been done. perhaps the most eminent and interesting man associated with me during this period was mr. george w. hill, who will easily rank as the greatest master of mathematical astronomy during the last quarter of the nineteenth century. the only defect of his make-up of which i have reason to complain is the lack of the teaching faculty. had this been developed in him, i could have learned very much from him that would have been to my advantage. in saying this i have one especial point in mind. in beginning my studies in celestial mechanics, i lacked the guidance of some one conversant with the subject on its practical side. two systems of computing planetary perturbations had been used, one by leverrier, while the other was invented by hansen. the former method was, in principle, of great simplicity, while the latter seemed to be very complex and even clumsy. i naturally supposed that the man who computed the direction of the planet neptune before its existence was known, must be a master of the whole subject, and followed the lines he indicated. i gradually discovered the contrary, and introduced modified methods, but did not entirely break away from the old trammels. hill had never been bound by them, and used hansen's method from the beginning. had he given me a few demonstrations of its advantages, i should have been saved a great deal of time and labor. the part assigned to hill was about the most difficult in the whole work,--the theory of jupiter and saturn. owing to the great mass of these "giant planets," the inequalities of their motion, especially in the case of saturn, affected by the attraction of jupiter, is greater than in the case of the other planets. leverrier failed to attain the necessary exactness in his investigation of their motion. hill had done some work on the subject at his home in nyack turnpike before i took charge of the office. he now moved to washington, and seriously began the complicated numerical calculations which his task involved. i urged that he should accept the assistance of less skilled computers; but he declined it from a desire to do the entire work himself. computers to make the duplicate computations necessary to guard against accidental numerical errors on his part were all that he required. he labored almost incessantly for about ten years, when he handed in the manuscript of what now forms volume iv. of the "astronomical papers." a pleasant incident occurred in 1884, when the office was honored by a visit from professor john c. adams of england, the man who, independently of leverrier, had computed the place of neptune, but failed to receive the lion's share of the honor because it happened to be the computations of the frenchman and not his which led immediately to the discovery of the planet. it was of the greatest interest to me to bring two such congenial spirits as adams and hill together. it would be difficult to find a more impressive example than that afforded by hill's career, of the difficulty of getting the public to form and act upon sane judgments in such cases as his. the world has the highest admiration for astronomical research, and in this sentiment our countrymen are foremost. they spend hundreds of thousands of dollars to promote it. they pay good salaries to professors who chance to get a certain official position where they may do good work. and here was perhaps the greatest living master in the highest and most difficult field of astronomy, winning world-wide recognition for his country in the science, and receiving the salary of a department clerk. i never wrestled harder with a superior than i did with hon. r. w. thompson, secretary of the navy, about 1880, to induce him to raise mr. hill's salary from $1200 to $1400. it goes without saying that hill took even less interest in the matter than i did. he did not work for pay, but for the love of science. his little farm at nyack turnpike sufficed for his home, and supplied his necessities so long as he lived there, and all he asked in washington was the means of going on with his work. the deplorable feature of the situation is, that this devotion to his science, instead of commanding due recognition on the public and official side, rather tended to create an inadequate impression of the importance of what he was doing. that i could not secure for him at least the highest official consideration is among the regretful memories of my official life. although, so far as the amount of labor is concerned, mr. hill's work upon jupiter and saturn is the most massive he ever undertook, his really great scientific merit consists in the development of a radically new method of computing the inequalities of the moon's motion, which is now being developed and applied by professor e. w. brown. his most marked intellectual characteristic is the eminently practical character of his researches. he does not aim so much at elegant mathematical formulæ, as to determine with the greatest precision the actual quantities of which mathematical astronomy stands in need. in this direction he has left every investigator of recent or present time far in the rear. after the computations on jupiter and saturn were made, it was necessary to correct their orbits and make tables of their motions. this work i left entirely in mr. hill's hands, the only requirement being that the masses of the planets and other data which he adopted should be uniform with those i used in the rest of the work. his tables were practically completed in manuscript at the beginning of 1892. when they were through, doubtless feeling, as well he might, that he had done his whole duty to science and the government, mr. hill resigned his office and returned to his home. during the summer he paid a visit to europe, and visiting the cambridge university, was honored with the degree of doctor of laws, along with a distinguished company, headed by the duke of edinburgh. one of the pleasant things to recall was that, during the fifteen years of our connection, there was never the slightest dissension or friction between us. i may add that the computations which he made on the theory of jupiter and saturn are all preserved complete and in perfect form at the nautical almanac office, so that, in case any question should arise respecting them in future generations, the point can be cleared up by an inspection. in 1874, three years before i left the observatory, i was informed by dr. henry draper that he had a mechanical assistant who showed great fondness for and proficiency in some work in mathematical astronomy. i asked to see what he was doing, and received a collection of papers of a remarkable kind. they consisted mainly of some of the complicated developments of celestial mechanics. in returning them i wrote to draper that, when i was ready to begin my work on the planetary theories, i must have his man,--could he possibly be spared? but he came to me before the time, while i was carrying on some investigations with aid afforded by the smithsonian institution. of course, when i took charge of the nautical almanac office, he was speedily given employment on its work. his name was john meier, a swiss by birth, evidently from the peasant class, but who had nevertheless been a pupil of professor rudolph wolf at zurich. emigrating to this country, he was, during the civil war, an engineer's mate or something of that grade in the navy. he was the most perfect example of a mathematical machine that i ever had at command. of original power,--the faculty of developing new methods and discovering new problems, he had not a particle. happily for his peace of mind, he was totally devoid of worldly ambition. i had only to prepare the fundamental data for him, explain what was wanted, write down the matters he was to start with, and he ground out day after day the most complicated algebraic and trigonometrical computations with untiring diligence and almost unerring accuracy. but a dark side of the picture showed itself very suddenly and unexpectedly in a few years. for the most selfish reasons, if for no others, i desired that his peace of mind should be undisturbed. the result was that i was from time to time appealed to as an arbitrator of family dissensions, in which it was impossible to say which side was right and which wrong. then, as a prophylactic against malaria, his wife administered doses of whiskey. the rest of the history need not be told. it illustrates the maxim that "blood will tell," which i fear is as true in scientific work as in any other field of human activity. a man of totally different blood, the best in fact, entered the office shortly before meier broke down. this was mr. cleveland keith, son of professor reuel keith, who was one of the professors at the observatory when it was started. his patience and ability led to his gradually taking the place of a foreman in supervising the work pertaining to the reduction of the observations, and the construction of the tables of the planets. without his help, i fear i should never have brought the tables to a conclusion. he died in 1896, just as the final results of the work were being put together. high among the troublesome problems with which i had to deal while in charge of the nautical almanac, was that of universal time. all but the youngest of my readers will remember the period when every railway had its own meridian, by the time of which its trains were run, which had to be changed here and there in the case of the great trunk lines, and which seldom agreed with the local time of a place. in the pennsylvania station at pittsburg were three different times; one that of philadelphia, one of some point farther west, and the third the local pittsburg time. the traveler was constantly liable to miss a train, a connection, or an engagement by the doubt and confusion thus arising. this was remedied in 1883 by the adoption of our present system of standard times of four different meridians, the introduction of which was one of the great reforms of our generation. when this change was made, i was in favor of using washington time as the standard, instead of going across the ocean to greenwich for a meridian. but those who were pressing the measure wanted to have a system for the whole world, and for this purpose the meridian of greenwich was the natural one. practically our purpose was served as well by the greenwich meridian as it would have been by that of washington. the year following this change an international meridian conference was held at washington, on the invitation of our government, to agree upon a single prime meridian to be adopted by the whole world in measuring longitudes and indicating time. of course the meridian of greenwich was the only one that would answer the purpose. this had already been adopted by several leading maritime nations, including ourselves as well as great britain. it was merely a question of getting the others to fall into line. no conference was really necessary for this purpose, because the dissentients caused much more inconvenience to themselves than to any one else by their divergent practice. the french held out against the adoption of the greenwich meridian, and proposed one passing through behring strait. i was not a member of the conference, but was invited to submit my views, which i did orally. i ventured to point out to the frenchmen that the meridian of greenwich also belonged to france, passing near havre and intersecting their country from north to south. it was therefore as much a french as an english meridian, and could be adopted without any sacrifice of national position. but they were not convinced, and will probably hold out until england adopts the metric system, on which occasion it is said that they will be prepared to adopt the greenwich meridian. one proceeding of the conference illustrates a general characteristic of reformers. almost without debate, certainly without adequate consideration, the conference adopted a recommendation that astronomers and navigators should change their system of reckoning time. both these classes have, from time immemorial, begun the day at noon, because this system was most natural and convenient, when the question was not that of a measure of time for daily life, but simply to indicate with mathematical precision the moment of an event. navigators had begun the day at noon, because the observations of the sun, on which the latitude of a ship depends, are necessarily made at noon, and the run of the ship is worked up immediately afterward. the proposed change would have produced unending confusion in astronomical nomenclature, owing to the difficulty of knowing in all cases which system of time was used in any given treatise or record of observations. i therefore felt compelled, in the general interest of science and public convenience, to oppose the project with all my power, suggesting that, if the new system must be put into operation, we should wait until the beginning of a new century. "i hope you will succeed in having its adoption postponed until 1900," wrote airy to me, "and when 1900 comes, i hope you will further succeed in having it again postponed until the year 2000." the german official astronomers, and indeed most of the official ones everywhere, opposed the change, but the efforts on the other side were vigorously continued. the british admiralty was strongly urged to introduce the change into the nautical almanac, and the question of doing this was warmly discussed in various scientific journals. one result of this movement was that, in 1886, rear-admiral george h. belknap, superintendent of the naval observatory, and myself were directed to report on the question. i drew up a very elaborate report, discussing the subject especially in its relations to navigation, pointing out in the strongest terms i could the danger of placing in the hands of navigators an almanac in which the numbers were given in a form so different from that to which they were accustomed. if they chanced to forget the change, the results of their computations might be out to any extent, to the great danger and confusion of their reckoning, while not a solitary advantage would be gained by it. there is some reason to suppose that this document found its way to the british admiralty, but i never heard a word further on the subject except that it ceased to be discussed in london. a few years later some unavailing efforts were made to revive the discussion, but the twentieth century is started without this confusing change being introduced into the astronomical ephemerides and nautical almanacs of the world, and navigators are still at liberty to practice the system they find most convenient. in 1894 i had succeeded in bringing so much of the work as pertained to the reduction of the observations and the determination of the elements of the planets to a conclusion. so far as the larger planets were concerned, it only remained to construct the necessary tables, which, however, would be a work of several years. with the year 1896 came what was perhaps the most important event in my whole plan. i have already remarked upon the confusion which pervaded the whole system of exact astronomy, arising from the diversity of the fundamental data made use of by the astronomers of foreign countries and various institutions in their work. it was, i think, rather exceptional that any astronomical result was based on entirely homogeneous and consistent data. to remedy this state of things and start the exact astronomy of the twentieth century on one basis for the whole world, was one of the objects which i had mapped out from the beginning. dr. a. m. w. downing, superintendent of the british nautical almanac, was struck by the same consideration and animated by the same motive. he had especially in view to avoid the duplication of work which arose from the same computations being made in different countries for the same result, whereby much unnecessary labor was expended. the field of astronomy is so vast, and the quantity of work urgently required to be done so far beyond the power of any one nation, that a combination to avoid all such waste was extremely desirable. when, in 1895, my preliminary results were published, he took the initiative in a project for putting the idea into effect, by proposing an international conference of the directors of the four leading ephemerides, to agree upon a uniform system of data for all computations pertaining to the fixed stars. this conference was held in paris in may, 1896. after several days of discussion, it resolved that, beginning with 1901, a certain set of constants should be used in all the ephemerides, substantially the same as those i had worked out, but without certain ulterior, though practically unimportant, modifications which i had applied for the sake of symmetry. my determination of the positions and motions of the bright fixed stars, which i had not yet completed, was adopted in advance for the same purpose, i agreeing to complete it if possible in time for use in 1901. i also agreed to make a new determination of the constant of precession, that which i had used in my previous work not being quite satisfactory. all this by no means filled the field of exact astronomy, yet what was left outside of it was of comparatively little importance for the special object in view. more than a year after the conference i was taken quite by surprise by a vigorous attack on its work and conclusions on the part of professor lewis boss, director of the dudley observatory, warmly seconded by mr. s. c. chandler of cambridge, the editor of the "astronomical journal." the main grounds of attack were two in number. the time was not ripe for concluding upon a system of permanent astronomical standards. besides this, the astronomers of the country should have been consulted before a decision was reached. ultimately the attack led to a result which may appear curious to the future astronomer. he will find the foreign ephemerides using uniform data worked out in the office of the "american ephemeris and nautical almanac" at washington for the years beginning with 1901. he will find that these same data, after being partially adopted in the ephemeris for 1900, were thrown out in 1901, and the antiquated ones reintroduced in the main body of the ephemeris. the new ones appear simply in an appendix. as, under the operation of law, i should be retired from active service in the march following the conference, it became a serious question whether i should be able to finish the work that had been mapped out, as well as the planetary tables. mr. secretary herbert, on his own motion so far as i know, sent for me to inquire into the subject. the result of the conference was a movement on his part to secure an appropriation somewhat less than the highest salary of a professor, to compensate me for the completion of the work after my retirement. the house committee on appropriations, ever mindful of economy in any new item, reduced the amount to a clerical salary. the committee of conference compromised on a mean between the two. it happened that the work on the stars was not specified in the law,--only the tables of the planets. in consequence i had no legal right to go on with the former, although the ephemerides of europe were waiting for the results. after much trouble an arrangement was effected under which the computers on the work were not to be prohibited from consulting me in its prosecution. astronomical work is never really done and finished. the questions growing out of the agreement or non-agreement of the tables with observations still remain to be studied, and require an immense amount of computation. in what country and by whom these computations will be made no one can now tell. the work which i most regretted to leave unfinished was that on the motion of the moon. as i have already said, this work is complete to 1750. the computations for carrying it on from 1750 to the present time were perhaps three fourths done when i had to lay them aside. in 1902, when the carnegie institution was organized, it made a grant for supplying me with the computing assistance and other facilities necessary for the work, and the secretary of the navy allowed me the use of the old computations. under such auspices the work was recommenced in march, 1903. so far as i can recall, i never asked anything from the government which would in any way promote my personal interests. the only exception, if such it is, is that during the civil war i joined with other professors in asking that we be put on the same footing with other staff corps of the navy as regarded pay and rank. so far as my views were concerned, the rank was merely a _pro forma_ matter, as i never could see any sound reason for a man pursuing astronomical duties caring to have military rank. in conducting my office also, the utmost economy was always studied. the increase in the annual appropriations for which i asked was so small that, when i left the office in 1877, they were just about the same as they were back in the fifties, when it was first established. the necessary funds were saved by economical administration. all this was done with a feeling that, after my retirement, the satisfaction with which one could look back on such a policy would be enhanced by a feeling on the part of the representatives of the public that the work i had done must be worthy of having some pains taken to secure its continuance in the same spirit. i do not believe that the men who conduct our own government are a whit behind the foremost of other countries in the desire to promote science. if after my retirement no special measures were deemed necessary to secure the continuance of the work in which i had been engaged, i prefer to attribute it to adventitious circumstances rather than to any undervaluation of scientific research by our authorities. ix scientific washington it is sometimes said that no man, in passing away, leaves a place which cannot be equally well filled by another. this is doubtless true in all ordinary cases. but scientific research, and scientific affairs generally at the national capital, form an exception to many of the rules drawn from experience in other fields. professor joseph henry, first secretary of the smithsonian institution, was a man of whom it may be said, without any reflection on men of our generation, that he held a place which has never been filled. i do not mean his official place, but his position as the recognized leader and exponent of scientific interests at the national capital. a world-wide reputation as a scientific investigator, exalted character and inspiring presence, broad views of men and things, the love and esteem of all, combined to make him the man to whom all who knew him looked for counsel and guidance in matters affecting the interests of science. whether any one could since have assumed this position, i will not venture to say; but the fact seems to be that no one has been at the same time able and willing to assume it. on coming to washington i soon became very intimate with professor henry, and i do not think there was any one here to whom he set forth his personal wishes and convictions respecting the policy of the smithsonian institution and its relations to the government more freely than he did to me. as every point connected with the history and policy of this establishment is of world-wide interest, and as professor henry used to put some things in a different light from that shed upon the subject by current publications, i shall mention a few points that might otherwise be overlooked. it has always seemed to me that a deep mystery enshrouded the act of smithson in devising his fortune as he did. that an englishman, whose connections and associations were entirely with the intellectual classes,--who had never, so far as is known, a single american connection, or the slightest inclination toward democracy,--should, in the intellectual condition of our country during the early years of the century, have chosen its government as his trustee for the foundation of a scientific institution, does of itself seem singular enough. what seems yet more singular is that no instructions whatever were given in his will or found in his papers beyond the comprehensive one "to found an institution at washington to be called the smithsonian institution for the increase and diffusion of knowledge among men." no plan of the institution, no scrap of paper which might assist in the interpretation of the mandate, was ever discovered. not a word respecting his intention was ever known to have been uttered. only a single remark was ever recorded which indicated that he had anything unusual in view. he did at one time say, "my name shall live in the memory of men when the titles of the northumberlands and the percys are extinct and forgotten." one result of this failure to indicate a plan for the institution was that, when the government received the money, congress was at a loss what to do with it. some ten years were spent in discussing schemes of various kinds, among them that of declining the gift altogether. then it was decided that the institution should be governed by a board of regents, who should elect a secretary as their executive officer and the administrator of the institution. the latter was to include a library, a museum, and a gallery of art. the plans for the fine structure, so well known to every visitor to the capital, were prepared, the building was started, the regents organized, and professor henry made secretary. we might almost say that henry was opposed to every special function assigned to the institution by the organic law. he did not agree with me as to any mystery surrounding the intentions of the founder. to him they were perfectly clear. smithson was a scientific investigator; and the increase and diffusion of knowledge among men could be best promoted on the lines that he desired, by scientific investigation and the publication of scientific researches. for this purpose a great building was not necessary, and he regretted all the money spent on it. the library, museum, and gallery of art would be of only local advantage, whereas "diffusion among men" implied all men, whether they could visit washington or not. it was clearly the business of the government to supply purely local facilities for study and research, and the endowment of smithson should not be used for such a purpose. his opposition to the building tinged the whole course of his thought. i doubt whether he was ever called upon by founders of institutions of any sort for counsel without his warning them to beware of spending their money in bricks and mortar. the building being already started before he took charge, and the three other objects being sanctioned by law, he was, of course, hampered in carrying out his views. but he did his utmost to reduce to a minimum the amount of the fund that should be devoted to the objects specified. this policy brought on the most animated contest in the history of the institution. it was essential that his most influential assistants should share his views or at least not thwart them. this, he found, was not the case. the librarian, mr. c. c. jewett, an able and accomplished man in the line of his profession, was desirous of collecting one of the finest scientific libraries. a contest arose, to which professor henry put an end by the bold course of removing the librarian from office. mr. jewett denied his power to do this, and the question came before the board of regents. the majority of these voted that the secretary had the power to remove his assistants. among the minority was rufus choate, who was so strongly opposed to the action that he emphasized his protest against it by resigning from the board. a question of legal interpretation came in to make the situation yet more difficult. the regents had resolved that, after the completion of the building, one half the income should be devoted to those objects which professor henry considered most appropriate. meanwhile there was no limit to the amount that might be appropriated to these objects, but mr. jewett and other heads of departments wished to apply the rule from the beginning. henry refused to do so, and looked with entire satisfaction on the slowness of completion of what was, in his eyes, an undesirable building. it must be admitted that there was one point which professor henry either failed to appreciate, or perhaps thought unworthy of consideration. this is, the strong hold on the minds of men which an institution is able to secure through the agency of an imposing building. saying nothing of the artistic and educational value of a beautiful piece of architecture, it would seem that such a structure has a peculiar power of impressing the minds of men with the importance of the object to which it is devoted, or of the work going on within it. had professor henry been allowed to perform all the functions of the smithsonian institution in a moderate-sized hired house, as he felt himself abundantly able to do, i have very serious doubts whether it would have acquired its present celebrity and gained its present high place in the estimation of the public. in the winter of 1865 the institution suffered an irreparable loss by a conflagration which destroyed the central portion of the building. at that time the gallery of art had been confined to a collection of portraits of indians by stanley. this collection was entirely destroyed. the library, being at one end, remained intact. the lecture room, where courses of scientific lectures had been delivered by eminent men of science, was also destroyed. this event gave professor henry an opportunity of taking a long step in the direction he desired. he induced congress to take the smithsonian library on deposit as a part of its own, and thus relieve the institution of the cost of supporting this branch. the corcoran art gallery had been founded in the mean time, and relieved the institution of all necessity for supporting a gallery of art. he would gladly have seen the national museum made a separate institution, and the smithsonian building purchased by the government for its use, but he found no chance of carrying this out. after the death of professor henry the institution grew rapidly into a position in which it might almost claim to be a scientific department of the government. the national museum, remaining under its administration, was greatly enlarged, and one of its ramifications was extended into the national zoölogical park. the studies of indian ethnology, begun by major j. w. powell, grew into the bureau of ethnology. the astrophysical observatory was established, in which professor langley has continued his epoch-making work on the sun's radiant heat with his wonderful bolometer, an instrument of his own invention. before he was appointed to succeed professor henry, professor baird was serving as united states fish commissioner, and continued to fill this office, without other salary than that paid by the smithsonian institution. the economic importance of the work done and still carried on by this commission is too well known to need a statement. about the time of baird's death, the work of the commission was separated from that of the institution by providing a salary for the commissioner. we have here a great extension of the idea of an institution for scientific publications and research. i recall once suggesting to professor baird the question whether the utilization of the institution founded by smithson for carrying on and promoting such government work as that of the national museum was really the right thing to do. he replied, "it is not a case of using the smithsonian fund for government work, but of the government making appropriations for the work of the smithsonian institution." between the two sides of the question thus presented,--one emphasizing the honor done to smithson by expanding the institution which bears his name, and the other aiming solely at the best administration of the fund which we hold in trust for him,--i do not pretend to decide. on the academic side of social life in washington, the numerous associations of alumni of colleges and universities hold a prominent place. one of the earliest of these was that of yale, which has held an annual banquet every year, at least since 1877, when i first became a member. its membership at this time included mr. w. m. evarts, then secretary of state, chief justice waite, senator dawes, and a number of other men prominent in political life. the most attractive speaker was mr. evarts, and the fact that his views of education were somewhat conservative added much to the interest of his speeches. he generally had something to say in favor of the system of a prescribed curriculum in liberal education, which was then considered as quite antiquated. when president dwight, shortly after his accession to office, visited the capital to explain the modernizing of the yale educational system, he told the alumni that the college now offered ninety-five courses to undergraduates. evarts congratulated the coming students on sitting at a banquet table where they had their choice of ninety-five courses of intellectual aliment. perhaps the strongest testimonial of the interest attached to these reunions was unconsciously given by president hayes. he had received an honorary degree from yale, and i chanced to be on the committee which called to invite him to the next banquet. he pleaded, as i suppose presidents always do, the multiplicity of his engagements, but finally said,-"well, gentlemen, i will come, but it must be on two well-understood conditions. in the first place, i must not be called to my feet. you must not expect a speech of me. the second condition is, i must be allowed to leave punctually at ten o'clock." "we regret your conditions, mr. president," was the reply, "but must, of course, accede to them, if you insist." he came to the banquet, he made a speech,--a very good, and not a very short one,--and he remained, an interested hearer, until nearly two o'clock in the morning. in recent years i cannot avoid a feeling that a change has come over the spirit of such associations. one might gather the impression that the apothegm of sir william hamilton needed a slight amendment. on earth is nothing great but man, in man is nothing great but mind. strike out the last word, and insert "muscle." the reader will please not misinterpret this remark. i admire the physically perfect man, loving everything out of doors, and animated by the spirit that takes him through polar snows and over mountain tops. but i do not feel that mere muscular practice during a few years of college life really fosters this spirit. among the former institutions of washington of which the memory is worth preserving, was the scientific club. this was one of those small groups, more common in other cities than in washington, of men interested in some field of thought, who meet at brief intervals at one another's houses, perhaps listen to a paper, and wind up with a supper. when or how the washington club originated, i do not know, but it was probably sometime during the fifties. its membership seems to have been rather ill defined, for, although i have always been regarded as a member, and am mentioned in mcculloch's book as such, [1] i do not think i ever received any formal notice of election. the club was not exclusively scientific, but included in its list the leading men who were supposed to be interested in scientific matters, and whose company was pleasant to the others. mr. mcculloch himself, general sherman, and chief justice chase are examples of the members of the club who were of this class. it was at the club meetings that i made the acquaintance of general sherman. his strong characteristics were as clearly seen at these evening gatherings as in a military campaign. his restlessness was such that he found it hard to sit still, especially in his own house, two minutes at a time. his terse sentences, leaving no doubt in the mind of the hearer as to what he meant, always had the same snap. one of his military letters is worth reviving. when he was carrying on his campaign in georgia against hood, the latter was anxious that the war should damage general commercial interests as little as possible; so he sent general sherman a letter setting forth the terms and conditions on which he, hood, would refrain from burning the cotton in his line of march, but leave it behind,--at as great length and with as much detail as if it were a treaty of peace between two nations. sherman's reply was couched in a single sentence: "i hope you will burn all the cotton you can, for all you don't burn i will." when he introduced two people, he did not simply mention their names, but told who each one was. in introducing the adjutant-general to another officer who had just come into washington, he added, "you know his signature." mr. mcculloch, who succeeded mr. chase as secretary of the treasury, was my beau idéal of an administrator. in his personal make-up, he was as completely the opposite of general sherman as a man well could be. deliberate, impassive, heavy of build, slow in physical movement, he would have been supposed, at first sight, a man who would take life easy, and concern himself as little as possible about public affairs. but, after all, there is a quality in the head of a great department which is quite distinct from sprightliness, and that is wisdom. this he possessed in the highest degree. the impress which he made on our fiscal system was not the product of what looked like energetic personal action, but of a careful study of the prevailing conditions of public opinion, and of the means at his disposal for keeping the movement of things in the right direction. his policy was what is sometimes claimed, and correctly, i believe, to embody the highest administrative wisdom: that of doing nothing himself that he could get others to do for him. in this way all his energies could be devoted to his proper work, that of getting the best men in office, and of devising measures from time to time calculated to carry the government along the lines which he judged to be best for the public interests. the name of another attendant at the meetings of the club has from time to time excited interest because of its connection with a fundamental principle of evolutionary astronomy. this principle, which looks paradoxical enough, is that up to a certain stage, as a star loses heat by radiation into space, its temperature becomes higher. it is now known as lane's law. some curiosity as to its origin, as well as the personality of its author, has sometimes been expressed. as the story has never been printed, i ask leave to tell it. among the attendants at the meetings of the scientific club was an odd-looking and odd-mannered little man, rather intellectual in appearance, who listened attentively to what others said, but who, so far as i noticed, never said a word himself. up to the time of which i am speaking, i did not even know his name, as there was nothing but his oddity to excite any interest in him. one evening about the year 1867, the club met, as it not infrequently did, at the home of mr. mcculloch. after the meeting mr. w. b. taylor, afterward connected with the smithsonian institution in an editorial capacity, accompanied by the little man, set out to walk to his home, which i believe was somewhere near the smithsonian grounds. at any rate, i joined them in their walk, which led through these grounds. a few days previous there had appeared in the "reader," an english weekly periodical having a scientific character, an article describing a new theory of the sun. the view maintained was that the sun was not a molten liquid, as had generally been supposed up to that time, but a mass of incandescent gas, perhaps condensed at its outer surface, so as to form a sort of immense bubble. i had never before heard of the theory, but it was so plausible that there could be no difficulty in accepting it. so, as we wended our way through the smithsonian grounds, i explained the theory to my companions in that _ex cathedra_ style which one is apt to assume in setting forth a new idea to people who know little or nothing of the subject. my talk was mainly designed for mr. taylor, because i did not suppose the little man would take any interest in it. i was, therefore, much astonished when, at a certain point, he challenged, in quite a decisive tone, the correctness of one of my propositions. in a rather more modest way, i tried to maintain my ground, but was quite silenced by the little man informing us that he had investigated the whole subject, and found so and so--different from what i had been laying down. i immediately stepped down from the pontifical chair, and asked the little man to occupy it and tell us more about the matter, which he did. whether the theorem to which i have alluded was included in his statement, i do not recall. if it was not, he told me about it subsequently, and spoke of a paper he had published, or was about to publish, in the "american journal of science." i find that this paper appeared in volume l. in 1870. naturally i cultivated the acquaintance of such a man. his name was j. homer lane. he was quite alone in the world, having neither family nor near relative, so far as any one knew. he had formerly been an examiner or something similar in the patent office, but under the system which prevailed in those days, a man with no more political influence than he had was very liable to lose his position, as he actually did. he lived in a good deal such a habitation and surroundings as men like johnson and goldsmith lived in in their time. if his home was not exactly a garret, it came as near it as a lodging of the present day ever does. after the paper in question appeared, i called mr. lane's attention to the fact that i did not find any statement of the theorem which he had mentioned to me to be contained in it. he admitted that it was contained in it only impliedly, and proceeded to give me a very brief and simple demonstration. so the matter stood, until the centennial year, 1876, when sir william thomson paid a visit to this country. i passed a very pleasant evening with him at the smithsonian institution, engaged in a discussion, some points of which he afterwards mentioned in an address to the british association. among other matters, i mentioned this law, originating with mr. j. homer lane. he did not think it could be well founded, and when i attempted to reproduce mr. lane's verbal demonstration, i found myself unable to do so. i told him i felt quite sure about the matter, and would write to him on the subject. when i again met mr. lane, i told him of my difficulty and asked him to repeat the demonstration. he did so at once, and i sent it off to sir william. the latter immediately accepted the result, and published a paper on the subject, in which the theorem was made public for the first time. it is very singular that a man of such acuteness never achieved anything else of significance. he was at my station on one occasion when a total eclipse of the sun was to be observed, and made a report on what he saw. at the same time he called my attention to a slight source of error with which photographs of the transit of venus might be affected. the idea was a very ingenious one, and was published in due course. altogether, the picture of his life and death remains in my memory as a sad one, the brightest gleam being the fact that he was elected a member of the national academy of sciences, which must have been to him a very grateful recognition of his work on the part of his scientific associates. when he died, his funeral was attended only by a few of his fellow members of the academy. altogether, i feel it eminently appropriate that his name should be perpetuated by the theorem of which i have spoken. if the national academy of sciences has not proved as influential a body as such an academy should, it has still taken such a place in science, and rendered services of such importance to the government, that the circumstances connected with its origin are of permanent historic interest. as the writer was not a charter member, he cannot claim to have been "in at the birth," though he became, from time to time, a repository of desultory information on the subject. there is abundant internal and circumstantial evidence that dr. b. a. gould, although his name has, so far as i am aware, never been mentioned in this connection, was a leading spirit in the first organization. on the other hand, curiously enough, professor henry was not. i was quite satisfied that bache took an active part, but henry assured me that he could not believe this, because he was so intimate with bache that, had the latter known anything of the matter, he would surely have consulted him. some recent light is thrown on the subject by letters of rear-admiral charles h. davis, found in his "life," as published by his son. everything was carried on in the greatest secrecy, until the bill chartering the body was introduced by senator henry wilson of massachusetts. fifty charter members were named, and this number was fixed as the permanent limit to the membership. the list did not include either george p. bond, director of the harvard observatory, perhaps the foremost american astronomer of the time in charge of an observatory, nor dr. john w. draper. yet the total membership in the section of astronomy and kindred sciences was very large. a story to which i give credence was that the original list, as handed to senator wilson, did not include the name of william b. rogers, who was then founding the institute of technology. the senator made it a condition that room for rogers should be found, and his wish was acceded to. it is of interest that the man thus added to the academy by a senator afterward became its president, and proved as able and popular a presiding officer as it ever had. the governmental importance of the academy arose from the fact that its charter made it the scientific adviser of the government, by providing that it should "investigate, examine, experiment, and report upon any subject of science or art" whenever called upon by any department of the government. in this respect it was intended to perform the same valuable functions for the government that are expected of the national scientific academies or societies of foreign countries. the academy was empowered to make its own constitution. that first adopted was sufficiently rigid and complex. following the example of european bodies of the same sort, it was divided into two classes, one of mathematical and physical, the other of natural science. each of these classes was divided into sections. a very elaborate system of procedure for the choice of new members was provided. any member absent from four consecutive stated meetings of the academy had his name stricken from the roll unless he communicated a valid reason for his absence. notwithstanding this requirement, the academy had no funds to defray the traveling expenses of members, nor did the government ever appropriate money for this purpose. for seven years it became increasingly doubtful whether the organization would not be abandoned. several of the most eminent members took no interest whatever in the academy,--did not attend the meetings, but did tender their resignations, which, however, were not accepted. this went on at such a rate that, in 1870, to avoid a threatened dissolution, a radical change was made in the constitution. congress was asked to remove the restriction upon the number of members, which it promptly did. classes and sections were entirely abandoned. the members formed but a single body. the method of election was simplified,--too much simplified, in fact. the election of new members is, perhaps, the most difficult and delicate function of such an organization. it is one which cannot be performed to public satisfaction, nor without making many mistakes; and the avoidance of the latter is vastly more difficult when the members are so widely separated and have little opportunity to discuss in advance the merits of the men from whom a selection is to be made. an ideal selection cannot be made until after a man is dead, so that his work can be summed up; but i think it may fairly be said that, on the whole, the selections have been as good as could be expected under the conditions. notwithstanding the indifference of the government to the possible benefits that the academy might render it, it has--in addition to numerous reports on minor subjects--made two of capital importance to the public welfare. one of these was the planning of the united states geological survey, the other the organization of a forestry system for the united states. during the years 1870-77, besides several temporary surveys or expeditions which had from time to time been conducted under the auspices of the government, there were growing up two permanent surveys of the territories. one of these was the geographical survey of territories west of the 100th meridian, under the chief of engineers of the army; the other was the geological survey of the territories under the interior department, of which the chief was professor f. v. hayden. the methods adopted by the two chiefs to gain the approval of the public and the favoring smiles of congress were certainly very different. wheeler's efforts were made altogether by official methods and through official channels. hayden considered it his duty to give the public every possible opportunity to see what he was doing and to judge his work. his efforts were chronicled at length in the public prints. his summers were spent in the field, and his winters were devoted to working up results and making every effort to secure influence. an attractive personality and extreme readiness to show every visitor all that there was to be seen in his collections, facilitated his success. one day a friend introduced a number of children with an expression of doubt as to the little visitors being welcome. "oh, i always like to have the children come here," he replied, "they influence their parents." he was so successful in his efforts that his organization grew apace, and soon developed into the geological survey of the territories. ostensibly the objects of the two organizations were different. one had military requirements mainly in view, especially the mapping of routes. hayden's survey was mainly in the interests of geology. practically, however, the two covered the same field in all points. the military survey extended its scope by including everything necessary for a complete geographical and geological atlas. the geological survey was necessarily a complete topographical and geological survey from the beginning. between 1870 and 1877, both were engaged in making an atlas of colorado, on the maps of which were given the same topographical features and the same lines of communication. parties of the two surveys mounted their theodolites on the same mountains, and triangulated the same regions. the hayden survey published a complete atlas of colorado, probably more finely gotten up than any atlas of a state in the union, while the wheeler survey was vigorously engaged in issuing maps of the same territory. no effort to prevent this duplication of work by making an arrangement between the two organizations led to any result. neither had any official knowledge of the work of the other. unofficially, the one was dissatisfied with the political methods of the other, and claimed that the maps which it produced were not fit for military purposes. hayden retorted with unofficial reflections on the geological expertness of the engineers, and maintained that their work was not of the best. he got up by far the best maps; wheeler, in the interests of economy, was willing to sacrifice artistic appearance to economy of production. we thus had the curious spectacle of the government supporting two independent surveys of the same region. various compromises were attempted, but they all came to nothing. the state of things was clear enough to congress, but the repugnance of our national legislature to the adoption of decisive measures of any sort for the settlement of a disputed administrative question prevented any effective action. infant bureaus may quarrel with each other and eat up the paternal substance, but the parent cannot make up his mind to starve them outright, or even to chastise them into a spirit of conciliation. unable to decide between them, congress for some years pursued the policy of supporting both surveys. the credit for introducing a measure which would certainly lead to unification is due to mr. a. s. hewitt, of new york, then a member of the committee on appropriations. he proposed to refer the whole subject to the national academy of sciences. his committee accepted his view, and a clause was inserted in the sundry civil bill of june 30, 1878, requiring the academy at its next meeting to take the matter into consideration and report to congress "as soon thereafter as may be practicable, a plan for surveying and mapping the territory of the united states on such general system as will, in their judgment, secure the best results at the least possible cost." several of the older and more conservative members of the academy objected that this question was not one of science or art, with which alone the academy was competent to deal, but was a purely administrative question which congress should settle for itself. they feared that the academy would be drawn into the arena of political discussion to an extent detrimental to its future and welfare and usefulness. whether the exception was or was not well taken, it was felt that the academy, the creature of congress, could not join issue with the latter as to its functions, nor should an opportunity of rendering a great service to the government be lost for such a reason as this. the plan reported by the academy was radical and comprehensive. it proposed to abolish all the existing surveys of the territories except those which, being temporary, were completing their work, and to substitute for them a single organization which would include the surveys of the public lands in its scope. the interior work of the coast and geodetic survey was included in the plan, it being proposed to transfer this bureau to the interior department, with its functions so extended as to include the entire work of triangulation. when the proposition came up in congress at the following session, it was vigorously fought by the chief of engineers of the army, and by the general land office, of which the surveying functions were practically abolished. the land office carried its point, and was eliminated from the scheme. general humphreys, the chief of engineers, was a member of the academy, but resigned on the ground that he could not properly remain a member while contesting the recommendations of the body. but the academy refused to accept the resignation, on the very proper ground that no obligation was imposed on the members to support the views of the academy, besides which, the work of the latter in the whole matter was terminated when its report was presented to congress. although this was true of the academy, it was not true of the individual members who had taken part in constructing the scheme. they were naturally desirous of seeing the plan made a success, and, in the face of such vigorous opposition, this required constant attention. a dexterous movement was that of getting the measure transferred from one appropriation bill to another when it passed over to the senate. the measure at length became a law, and thus was established the geological survey of the united states, which was to be governed by a director, appointed by the president, by and with the advice and consent of the senate. then, on march 4, 1879, an important question arose. the right man must be placed at the head of the new bureau. who is he? at first there seemed to be but one voice on the subject, professor hayden had taken the greatest pains to make known the work of his survey, not only to congress, but to every scientific society, small and great, the world over. many of these had bestowed their approbation upon it by electing its director to honorary membership. it has been said, i do not know how truly, that the number of these testimonials exceeded that received by any other scientific man in america. if this were so, they would have to be counted, not weighed. it was, therefore, not surprising that two thirds of the members of congress were said to have sent a recommendation to the president for the appointment of so able and successful a man to the new position. the powerful backing of so respectable a citizen as hon. j. d. cox, formerly secretary of the interior, was also heartily proffered. to these forces were added that of a certain number of geologists, though few or none of them were leaders in the science. had it not been for a private intimation conveyed to secretary schurz that the scientific men interested might have something to say on the subject, hayden might have been appointed at the very moment the bill was signed by the president. notwithstanding all of hayden's merits as the energetic head of a survey, the leaders in the movement considered that mr. clarence king was the better qualified for the duties of the new position. it is not unlikely that a preference for a different method of influencing congress than that which i have described, was one of the reasons in favor of mr. king. he was a man of charming personality and great literary ability. some one said of him that he could make a more interesting story out of what he saw during a ride in a street car than most men could with the best material at their disposal. his "mountaineering in the sierra nevadas" was as interesting an account of western exploration as has ever been published. i understand it was suppressed by the author because some of the characters described in it were much hurt by finding themselves painted in the book. hopeless though the contest might have seemed, an effort was made by three or four of the men most interested to secure mr. king's appointment. if i wanted to show the fallacy of the common impression that scientific men are not fitted for practical politics, i could not do it better than by giving the internal history of the movement. this i shall attempt only in the briefest way. the movers in the matter divided up the work, did what they could in the daytime, and met at night at wormley's hotel to compare notes, ascertain the effect of every shot, and decide where the next one should be fired. as all the parties concerned in the matter have now passed off the stage, i shall venture to mention one of these shots. one eminent geologist, whose support was known to be available, had not been called in, because an impression had been formed that president hayes would not be willing to consider favorably what he might say. after the matter had been discussed at one or two meetings, one of the party proposed to sound the president on the subject at his next interview. so, when the occasion arose, he gently introduced the name of the gentleman. "what view does he take?" inquired the president. "i think he will be favorable to mr. king," was the reply; "but would you give great weight to his opinion?" "i would give great weight to it, very great weight, indeed," was the reply. this expression was too decided in its tone to leave any doubt, and the geologist in question was on his way to washington as soon as electricity could tell him that he was wanted. when the time finally came for a decision, the president asked secretary schurz for his opinion. both agreed that king was the man, and he was duly appointed. the new administration was eminently successful. but king was not fond of administrative work, and resigned the position at the end of a year or so. he was succeeded by john w. powell, under whom the survey grew with a rapidity which no one had anticipated. as originally organized, the survey was one of the territories only, but the question whether it should not be extended to the states as well, and prepare a topographical atlas of the whole country, was soon mooted, and decided by congress in the affirmative. for this extension, however, the original organizers of the survey were in no way responsible. it was the act of congress, pure and simple. if the success of an organization is to be measured by the public support which it has commanded, by the extension of its work and influence, and by the gradual dying out of all opposition, it must be admitted that the plan of the academy was a brilliant success. it is true that a serious crisis had once to be met. while mr. cleveland was governor of new york, his experience with the survey of that state had led him to distrust the methods on which the surveys of the united states were being conducted. this distrust seems to have pervaded the various heads of the departments under his administration, and led to serious charges against the conduct of both the coast and geological surveys. an unfavorable report upon the administration of the former was made by a committee especially appointed by the secretary of the treasury, and led to the resignation of its superintendent. but, in the case of the geological survey, the attacks were mostly conducted by the newspapers. at length, director powell asked permission of secretary lamar to write him a letter in reply. his answers were so sweeping, and so conclusive on every point, that nothing more was heard of the criticisms. the second great work of the academy for the government was that of devising a forestry system for the united states. the immediate occasion for action in this direction was stated by secretary hoke smith to be the "inadequacy and confusion of existing laws relating to the public timber lands and consequent absence of an intelligent policy in their administration, resulting in such conditions as may, if not speedily stopped, prevent the proper development of a large part of our country." even more than in the case of the geological survey might this work seem to be one of administration rather than of science. but granting that such was the case, the academy commanded great advantages in taking up the subject. the commission which it formed devoted more than a year to the study, not only of the conditions in our own country, but of the various policies adopted by foreign countries, especially germany, and their results. as in the case of the geological survey, a radically new and very complete system of forestry administration was proposed. interests having other objects than the public good were as completely ignored as they had been before. the soundness of the conclusions reached by the academy commission were challenged by men wielding great political power in their respective states. for a time it was feared that the academy would suffer rather than gain in public opinion by the report it had made. but the moral force behind it was such that, in the long run, some of the severest critics saw their error, and a plan was adopted which, though differing in many details from that proposed, was, in the main, based on the conclusion of the commission. the interior department, the geological survey, and the department of agriculture all have their part in the work. notwithstanding these signal demonstrations of the valuable service which the academy may render to the government, the latter has done nothing for it. the immediate influence of the leading scientific men in public affairs has perhaps been diminished as much in one direction as it has been increased in another by the official character of the organization. the very fact that the members of the academy belong to a body which is, officially, the scientific adviser of the government, prevents them from coming forward to exercise that individual influence which they might exercise were no such body in existence. the academy has not even a place of meeting, nor is a repository for its property and records provided for it. although it holds in trust large sums which have been bequeathed from time to time by its members for promoting scientific investigation, and is, in this way, rendering an important service to the progress of knowledge, it has practically no income of its own except the contributions of its own members, nearly all of whom are in the position described by the elder agassiz, of having "no time to make money." among the men who have filled the office of president of the academy, professor o. c. marsh was perhaps the one whose activity covered the widest field. though long well known in scientific circles, he first came into public prominence by his exposure of the frauds practiced by contractors in furnishing supplies for the indians. this business had fallen into the hands of a small ring of contractors known as the "indian ring," who knew the ropes so well that they could bid below any competitor and yet manage things so as to gain a handsome profit out of the contracts. in the course of his explorations marsh took pains to investigate the whole matter, and published his conclusions first in the new york "tribune," and then more fully in pamphlet form, taking care to have public attention called to the subject so widely that the authorities would have to notice it. in doing so, mr. delano, secretary of the interior, spoke of them as charges made by "a mr. marsh." this method of designating such a man was made effective use of by mr. delano's opponents in the case. although the investigation which followed did not elicit all the facts, it had the result of calling the attention of succeeding secretaries of the interior to the necessity of keeping the best outlook on the administration of indian affairs. what i believe to have been the final downfall of the ring was not brought about until cleveland's first administration. then it happened in this way. mr. lamar, the secretary of the interior, was sharply on the lookout for frauds of every kind. as usual, the lowest bid for a certain kind of blanket had been accepted, and the secretary was determined to see whether the articles furnished actually corresponded with the requirements of the contract. it chanced that he had as his appointment clerk mr. j. j. s. hassler, a former manufacturer of woolen goods. mr. hassler was put on the board to inspect the supplies, and found that the blankets, although to all ordinary appearance of the kind and quality required, were really of a much inferior and cheaper material. the result was the enforced failure of the contractor, and, i believe, the end of the indian ring. marsh's explorations in search of fossil remains of the animals which once roamed over the western parts of our continent were attended by adventures of great interest, which he long had the intention of collecting and publishing in book form. unfortunately, he never did it, nor, so far as i am aware, has any connected narrative of his adventures ever appeared in print. this is more to be regretted, because they belong to a state of things which is rapidly passing away, leaving few records of that lifelike sort which make the most impressive picture. his guide during his early explorations was a character who has since become celebrated in america and europe by the vivid representations of the "wild west" with which he has amused and instructed the dwellers on two continents. marsh was on his way to explore the region in the rocky mountains where he was to find the fossils which have since made his work most celebrated. the guide was burning with curiosity as to the object of the expedition. one night over the campfire he drew his chief into a conversation on the subject. the latter told him that there was once a time when the rocky mountains did not exist, and that part of the continent was a level plain. in the course of long ages mountains rose, and animals ran over them. then the mountains split open; the animals died and left their bones in the clefts. the object of his expedition was now to search for some of these bones. the bones were duly discovered, and it was not many years thereafter before the wild west exhibition was seen in the principal eastern cities. when it visited new haven, its conductor naturally renewed the acquaintance of his former patron and supporter. "do you remember, professor," said he, "our talk as we were going on your expedition to the rockies,--how you told me about the mountains rising up and being split open and the bones of animals being lost in there, and how you were going to get them?" "oh, yes," said the other, "i remember it very well." "well, professor, do you know, when you told me all that i r'ally thought you was puttin' up a job on me." the result was a friendship between the two men, which continued during marsh's whole life. when the one felt that he ought no longer to spend all the money he earned, he consulted marsh on the subject of "salting it down," and doubtless got good advice. as an exposer of humbugs marsh took a prominent place. one of these related to the so-called "cardiff giant." sometime in 1869 the newspapers announced the discovery in northern new york, near the canadian border, of an extraordinary fossil man, or colossal statue, people were not sure which, eight or ten feet high. it was found several feet below the ground while digging a well. men of some scientific repute, including even one so eminent as professor james hall, had endorsed the genuineness of the find, and, on the strength of this, it was taken around to show the public. in the course of a journey through new york state, marsh happened to pass through the town where the object was on exhibition. his train stopped forty minutes for dinner, which would give him time to drive to the place and back, and leave a margin of about fifteen minutes for an examination of the statue. hardly more than a glance was necessary to show its fraudulent character. inside the ears the marks of a chisel were still plainly visible, showing that the statue had been newly cut. one of the most curious features was that the stone had not been large enough to make the complete statue, so that the surface was, in one place, still in the rough. the object had been found in wet ground. its material was sulphate of lime, the slight solubility of which would have been sufficient to make it dissolve entirely away in the course of centuries. the absence of any degradation showed that the thing was comparatively new. on the strength of this, marsh promptly denounced the affair as a humbug. only a feeble defense was made for it, and, a year or two later, the whole story came out. it had been designed and executed somewhere in the northwest, transported to the place where discovered, and buried, to be afterward dug up and reported as a prehistoric wonder. only a few years ago the writer had an opportunity of seeing with what wonderful ease intelligent men can be imposed upon by these artificial antiquities. the would-be exhibitor of a fossil woman, found i know not where, appeared in washington. he had not discovered the fossil himself, but had purchased it for some such sum as $100, on the assurance of its genuine character. he seems, however, to have had some misgivings on the subject, and, being an honest fellow, invited some washington scientific men to examine it in advance of a public exhibition. the first feature to strike the critical observer was that the arms of the fossil were crossed over the breast in the most approved undertaker's fashion, showing that if the woman had ever existed, she had devoted her dying moments to arranging a pose for the approval of posterity. little more than a glance was necessary to show that the fossil was simply baked clay. yet the limbs were hard and stiff. one of the spectators therefore asked permission of the owner to bore with an auger into the leg and see what was inside. a few moments' work showed that the bone of the leg was a bar of iron, around which clay had been moulded and baked. i must do the crestfallen owner the justice to say that his anxiety to convince the spectators of his own good faith in the matter far exceeded his regret at the pecuniary loss which he had suffered. another amusing experience that marsh had with a would-be fossil arose out of the discovery here and there in connecticut of the fossil footprints of birds. shortly after a find of this kind had been announced, a farmer drove his wagon up in front of the peabody museum, called on the professor, and told him he had dug up something curious on his farm, and he wished the professor would tell him what it was. he thought it looked like the footprints of a bird in a stone, but he was not quite sure. marsh went out and looked at the stone. a single glance was enough. "oh, i see what they are. they are the footprints of the domestic turkey. and the oddest part of it is, they are all made with the right foot." the simple-minded countryman, in making the prints with the turkey's foot, had overlooked the difference between the right and left foot, and the consequent necessity of having the tracks which pertained to the two feet alternate. washington is naturally a centre of information on all subjects relating to the aboriginal tribes of america and to life on the plains generally. besides the geological survey, the bureau of ethnology has been an active factor in this line. an official report cannot properly illustrate life in all its aspects, and therefore should be supplemented by the experiences of leading explorers. this is all the more necessary if, as seems to be the case, the peculiar characteristics of the life in question are being replaced by those more appropriate to civilization. yet the researches of the bureau in question are not carried on in any narrow spirit, and will supply the future student of humanity with valuable pictures of the most heroic of all races, and yet doomed, apparently, to ultimate extinction. i do not think i ever saw a more impressive human figure and face than those of chief joseph as he stood tall, erect, and impassive, at a president's reception in the winter of 1903. he was attired in all the brilliancy of his official costume; but not a muscle of his strongly marked face betrayed the sentiments with which he must have gazed on the shining uniforms passing before him. [1] _men and measures of half a century_, by hugh mcculloch. new york: chas. scribner's sons, 1889. x scientific england my first trip to europe, mentioned in the last chapter, was made with my wife, when the oldest transatlantic line was still the fashionable one. the passenger on a cunarder felt himself amply compensated for poor attendance, coarse food, and bad coffee by learning from the officers on the promenade deck how far the ships of their line were superior to all others in strength of hull, ability of captain, and discipline of crew. things have changed on both sides since then. although the cunard line has completed its half century without having lost a passenger, other lines are also carefully navigated, and the cunard passenger, so far as i know, fares as well as any other. captain mcmickan was as perfect a type of the old-fashioned captain of the best class as i ever saw. his face looked as if the gentlest zephyr that had ever fanned it was an atlantic hurricane, and yet beamed with hibernian good humor and friendliness. he read prayers so well on sunday that a passenger assured him he was born to be a bishop. one day a ship of the north german lloyd line was seen in the offing slowly gaining on us. a passenger called the captain's attention to the fact that we were being left behind. "oh, they're very lightly built, them german ships; built to carry german dolls and such like cargo." in london one of the first men we met was thomas hughes, of rugby fame, who made us feel how worthy he was of the love and esteem bestowed upon him by americans. he was able to make our visit pleasant in more ways than one. among the men i wanted to see was mr. john stuart mill, to whom i was attracted not only by his fame as a philosopher and the interest with which i had read his books, but also because he was the author of an excellent pamphlet on the union side during our civil war. on my expressing a desire to make mr. mill's acquaintance, mr. hughes immediately offered to give me a note of introduction. mill lived at blackheath, which, though in an easterly direction down the thames, is one of the prettiest suburbs of the great metropolis. his dwelling was a very modest one, entered through a passage of trellis-work in a little garden. he was by no means the grave and distinguished-looking man i had expected to see. he was small in stature and rather spare, and did not seem to have markedly intellectual features. the cordiality of his greeting was more than i could have expected; and he was much pleased to know that his work in moulding english sentiment in our favor at the commencement of the civil war was so well remembered and so highly appreciated across the atlantic. as a philosopher, it must be conceded that mr. mill lived at an unfortunate time. while his vigor and independence of thought led him to break loose from the trammels of the traditional philosophy, modern scientific generalization had not yet reached a stage favorable to his becoming a leader in developing the new philosophy. still, whatever may be the merits of his philosophic theories, i believe that up to a quite recent time no work on scientific method appeared worthy to displace his "system of logic." a feature of london life that must strongly impress the scientific student from our country is the closeness of touch, socially as well as officially, between the literary and scientific classes on the one side and the governing classes on the other. mr. hughes invited us to make an evening call with him at the house of a cabinet minister,--i think it was mr. goschen,--where we should find a number of persons worth seeing. among those gathered in this casual way were mr. gladstone, dean stanley, and our general burnside, then grown quite gray. i had never before met general burnside, but his published portraits were so characteristic that the man could scarcely have been mistaken. the only change was in the color of his beard. then and later i found that a pleasant feature of these informal "at homes," so universal in london, is that one meets so many people he wants to see, and so few he does not want to see. congress had made a very liberal appropriation for observations of the solar eclipse,--the making of which was one object of my visit,--to be expended under the direction of professor peirce, superintendent of the coast survey. peirce went over in person to take charge of the arrangements. he arrived in london with several members of his party a few days before we did, and about the same time came an independent party of my fellow astronomers from the naval observatory, consisting of professors hall, harkness, and eastman. the invasion of their country by such an army of american astronomers quite stirred up our english colleagues, who sorrowfully contrasted the liberality of our government with the parsimony of their own, which had, they said, declined to make any provision for the observations of the eclipse. considering that it was visible on their own side of the atlantic, they thought their government might take a lesson from ours. of course we could not help them directly; and yet i suspect that our coming, or at least the coming of peirce, really did help them a great deal. at any rate, it was a curious coincidence that no sooner did the american invasion occur than it was semi-officially discovered that no application of which her majesty's government could take cognizance had been made by the scientific authorities for a grant of money with which to make preparations for observing the eclipse. that the scientific authorities were not long in catching so broad a hint as this goes without saying. a little more of the story came out a few days later in a very unexpected way. in scientific england, the great social event of the year is the annual banquet of the royal society, held on st. andrew's day, the date of the annual meeting of the society, and of the award of its medals for distinguished work in science. at the banquet the scientific outlook is discussed not only by members of the society, but by men high in political and social life. the medalists are toasted, if they are present; and their praises are sung, if, as is apt to be the case with foreigners, they are absent. first in rank is the copley medal, founded by sir godfrey copley, a contemporary of newton. this medal has been awarded annually since 1731, and is now considered the highest honor that scientific england has to bestow. the recipient is selected with entire impartiality as to country, not for any special work published during the year, but in view of the general merit of all that he has done. five times in its history the medal has crossed the atlantic. it was awarded to franklin in 1753, agassiz in 1861, dana in 1877, and j. willard gibbs in 1902. the long time that elapsed between the first and the second of these awards affords an illustration of the backwardness of scientific research in america during the greater part of the first century of our independence. the year of my visit the medal was awarded to mr. joule, the english physicist, for his work on the relation of heat and energy. i was a guest at the banquet, which was the most brilliant function i had witnessed up to that time. the leaders in english science and learning sat around the table. her majesty's government was represented by mr. gladstone, the premier, and mr. lowe, afterward viscount sherbrooke, chancellor of the exchequer. both replied to toasts. mr. lowe as a speaker was perhaps a little dull, but not so mr. gladstone. there was a charm about the way in which his talk seemed to display the inner man. it could not be said that he had either the dry humor of mr. evarts or the wit of mr. depew; but these qualities were well replaced by the vivacity of his manner and the intellectuality of his face. he looked as if he had something interesting he wanted to tell you; and he proceeded to tell it in a very felicitous way as regarded both manner and language, but without anything that savored of eloquence. he was like carl schurz in talking as if he wanted to inform you, and not because he wanted you to see what a fine speaker he was. with this he impressed one as having a perfect command of his subject in all its bearings. i did not for a moment suppose that the premier of england could have taken any personal interest in the matter of the eclipse. great, therefore, was my surprise when, in speaking of the relations of the government to science, he began to talk about the coming event. i quote a passage from memory, after twenty-seven years: "i had the pleasure of a visit, a few days since, from a very distinguished american professor, professor peirce of harvard. in the course of the interview, the learned gentleman expressed his regret that her majesty's government had declined to take any measures to promote observations of the coming eclipse of the sun by british astronomers. i replied that i was not aware that the government had declined to take such measures. indeed, i went further, and assured him that any application from our astronomers for aid in making these observations would receive respectful consideration." i felt that there might be room for some suspicion that this visit of professor peirce was a not unimportant factor in the changed position of affairs as regarded british observations of the eclipse. not only the scene i have described, but subsequent experience, has impressed me with the high appreciation in which the best scientific work is held by the leading countries of europe, especially england and france, as if the prosecution were something of national importance which men of the highest rank thought it an honor to take part in. the marquis of salisbury, in an interval between two terms of service as premier of england, presided over the british association for the advancement of science, and delivered an address showing a wide and careful study of the generalizations of modern science. in france, also, one great glory of the nation is felt to be the works of its scientific and learned men of the past and present. membership of one of the five academies of the institute of france is counted among the highest honors to which a frenchman can aspire. most remarkable, too, is the extent to which other considerations than that of merit are set aside in selecting candidates for this honor. quite recently a man was elected a member of the academy of sciences who was without either university or official position, and earned a modest subsistence as a collaborator of the "revue des deux mondes." but he had found time to make investigations in mathematical astronomy of such merit that he was considered to have fairly earned this distinction, and the modesty of his social position did not lie in his way. at the time of this visit lister was an eminent member of the medical profession, but had not, so far as i am aware, been recognized as one who was to render incalculable service to suffering humanity. from a professional point of view there are no two walks in life having fewer points of contact than those of the surgeon and the astronomer. it is therefore a remarkable example of the closeness of touch among eminent englishmen in every walk of life, that, in subsequent visits, i was repeatedly thrown into contact with one who may fairly be recommended as among the greatest benefactors of the human race that the nineteenth century has given us. this was partly, but not wholly, due to his being, for several years, the president of the royal society. i would willingly say much more, but i am unable to write authoritatively upon the life and work of such a man, and must leave gossip to the daily press. for the visiting astronomer at london scarcely a place in london has more attractions than the modest little observatory and dwelling house on upper tulse hill, in which sir william huggins has done so much to develop the spectroscopy of the fixed stars. the owner of this charming place was a pioneer in the application of the spectroscope to the analysis of the light of the heavenly bodies, and after nearly forty years of work in this field, is still pursuing his researches. the charm of sentiment is added to the cold atmosphere of science by the collaboration of lady huggins. almost at the beginning of his work mr. huggins, analyzing the light of the great nebula of orion, showed that it must proceed from a mass of gas, and not from solid matter, thus making the greatest step possible in our knowledge of these objects. he was also the first to make actual measures of the motions of bright stars to or from our system by observing the wave length of the rays of light which they absorbed. quite recently an illustrated account of his observatory and its work has appeared in a splendid folio volume, in which the rigor of science is tempered with a gentle infusion of art which tempts even the non-scientific reader to linger over its pages. in england, the career of professor cayley affords an example of the spirit that impels a scientific worker of the highest class, and of the extent to which an enlightened community may honor him for what he is doing. one of the creators of modern mathematics, he never had any ambition beyond the prosecution of his favorite science. i first met him at a dinner of the astronomical society club. as the guests were taking off their wraps and assembling in the anteroom, i noticed, with some surprise, that one whom i supposed to be an attendant was talking with them on easy terms. a moment later the supposed attendant was introduced as professor cayley. his garb set off the seeming haggardness of his keen features so effectively that i thought him either broken down in health or just recovering from some protracted illness. the unspoken words on my lips were, "why, professor cayley, what has happened to you?" being now in the confessional, i must own that i did not, at the moment, recognize the marked intellectuality of a very striking face. as a representation of a mathematician in the throes of thought, i know nothing to equal his portrait by dickenson, which now hangs in the hall of trinity college, cambridge, and is reproduced in the sixth volume of cayley's collected works. his life was that of a man moved to investigation by an uncontrollable impulse; the only sort of man whose work is destined to be imperishable. until forty years of age he was by profession a conveyancer. his ability was such that he might have gained a fortune by practicing the highest branch of english law, if his energies had not been diverted in another direction. the spirit in which he pursued his work may be judged from an anecdote related by his friend and co-worker, sylvester, who, in speaking of cayley's even and placid temper, told me that he had never seen him ruffled but once. entering his office one morning, intent on some new mathematical thought which he was discussing with sylvester, he opened the letter-box in his door and found a bundle of papers relating to a law case which he was asked to take up. the interruption was too much. he flung the papers on the table with remarks more forcible than complimentary concerning the person who had distracted his attention at such an inopportune moment. in 1863 he was made a professor at cambridge, where, no longer troubled with the intricacies of land tenure, he published one investigation after another with ceaseless activity, to the end of his life. among my most interesting callers was professor john c. adams, of whom i have spoken as sharing with leverrier the honor of having computed the position of the planet neptune before its existence was otherwise known. the work of the two men was prosecuted at almost the same time, but adopting the principle that priority of publication should be the sole basis of credit, arago had declared that no other name than that of leverrier should even be mentioned in connection with the work. if repute was correct, leverrier was not distinguished for those amiable qualities that commonly mark the man of science and learning. his attitude toward adams had always been hostile. under these conditions chance afforded the latter a splendid opportunity of showing his superiority to all personal feeling. he was president of the royal astronomical society when its annual medal was awarded to his french rival for his work in constructing new tables of the sun and planets. it thus became his duty to deliver the address setting forth the reasons for the award. he did this with a warmth of praise for leverrier's works which could not have been exceeded had the two men been bosom friends. adams's intellect was one of the keenest i ever knew. the most difficult problems of mathematical astronomy and the most recondite principles that underlie the theory of the celestial motions were to him but child's play. his works place him among the first mathematical astronomers of the age, and yet they do not seem to do his ability entire justice. indeed, for fifteen years previous to the time of my visit his published writings had been rather meagre. but i believe he was justly credited with an elaborate witticism to the following effect: "in view of the fact that the only human being ever known to have been killed by a meteorite was a monk, we may concede that after four hundred years the pope's bull against the comet has been justified by the discovery that comets are made up of meteorites." those readers who know on what imperfect data men's impressions are sometimes founded will not be surprised to learn of my impression that an englishman's politics could be inferred from his mental and social make-up. if all men are born either aristotelians or platonists, then it may be supposed that all englishmen are born conservatives or liberals. the utterances of english journalists of the conservative party about american affairs during and after our civil war had not impressed me with the idea that one so unfortunate as to be born in that party would either take much interest in meeting an american or be capable of taking an appreciative view of scientific progress. so confident was i of my theory that i remarked to a friend with whom i had become somewhat intimate, that no one who knew mr. adams could have much doubt that he was a liberal in politics. an embarrassed smile spread over the friend's features. "you would not make that conclusion known to mr. adams, i hope," said he. "but is he not a liberal?" "he is not only a conservative, but declares himself 'a tory of the tories.'" i afterward found that he fully justified his own description. at the university, he was one of the leading opponents of those measures which freed the academic degrees from religious tests. he was said to have been among those who objected to sylvester, a jew, receiving a degree. i had decided to observe the eclipse at gibraltar. in order that my results, if i obtained any, might be utilized in the best way, it was necessary that the longitude of the station should be determined by telegraph. this had never been done for gibraltar. how great the error of the supposed longitude might have been may be inferred from the fact that a few years later, captain f. green of the united states navy found the longitude of lisbon on the admiralty charts to be two miles in error. the first arrangements i had to make in england were directed to this end. considering the relation of the world's great fortress to british maritime supremacy, it does seem as if there were something presumptuous in the coolness with which i went among the authorities to make arrangements for the enterprise. nevertheless, the authorities permitted the work, with a cordiality which was of itself quite sufficient to remove any such impression, had it been entertained. the astronomers did, indeed, profess to feel it humiliating that the longitude of such a place as gibraltar should have to be determined from greenwich by an american. they did not say "by a foreigner," because they always protested against americans looking upon themselves as such. still, it would not be an english enterprise if an american carried it out. i suspect, however, that my proceedings were not looked upon with entire dissatisfaction even by the astronomers. they might prove as good a stimulant to their government in showing a little more enterprise in that direction as the arrival of our eclipse party did. the longitude work naturally took me to the royal observatory which has made the little town of greenwich so famous. it is situated some eight miles east from charing cross, on a hill in greenwich park, with a pleasant outlook toward the thames. from my youth up i had been working with its observations, and there was no institution in the world which i had approached, or could approach, with the interest i felt in ascending the little hill on which it is situated. when the calabria was once free from her wharf in new york harbor, and on her way down the narrows, the foremost thought was, "off for europe; we shall see greenwich!" the day of my arrival in london i had written to professor airy, and received an answer the same evening, inviting us to visit the observatory and spend an afternoon with him a day or two later. i was shown around the observatory by an assistant, while my wife was entertained by mrs. airy and the daughters inside the dwelling. the family dined as soon as the day's work was over, about the middle of the afternoon. after the meal, we sat over a blazing fire and discussed our impressions of london. "what place in london interested you most?" said airy to my wife. "the first place i went to see was cavendish square." "what was there in cavendish square to interest you?" "when i was a little girl, my mother once gave me, as a birthday present, a small volume of poems. the first verse in the book was:- "'little ann and her mother were walking one day through london's wide city so fair; and business obliged them to go by the way that led them through cavendish square.'" to our astonishment the astronomer royal at once took up the thread:- "'and as they passed by the great house of a lord, a beautiful chariot there came, to take some most elegant ladies abroad, who straightway got into the same,'" and went on to the end. i do not know which of the two was more surprised: airy, to find an american woman who was interested in his favorite ballad, or she to find that he could repeat it by heart. the incident was the commencement of a family friendship which has outlived both the heads of the airy family. we may look back on airy as the most commanding figure in the astronomy of our time. he owes this position not only to his early works in mathematical astronomy, but also to his ability as an organizer. before his time the working force of an observatory generally consisted of individual observers, each of whom worked to a greater or less extent in his own way. it is true that organization was not unknown in such institutions. nominally, at least, the assistants in a national observatory were supposed to follow the instructions of a directing head. this was especially the case at greenwich. still, great dependence was placed upon the judgment and ability of the observer himself, who was generally expected to be a man well trained in his specialty, and able to carry on good work without much help. from airy's point of view, it was seen that a large part of the work necessary to the attainment of the traditional end of the royal observatory was of a kind that almost any bright schoolboy could learn to do in a few weeks, and that in most of the remaining part plodding industry, properly directed, was more important than scientific training. he could himself work out all the mathematical formulæ and write all the instructions required to keep a small army of observers and computers employed, and could then train in his methods a few able lieutenants, who would see that all the details were properly executed. under these lieutenants was a grade comprising men of sufficient technical education to enable them to learn how to point the telescope, record a transit, and perform the other technical operations necessary in an astronomical observation. a third grade was that of computers: ingenious youth, quick at figures, ready to work for a compensation which an american laborer would despise, yet well enough schooled to make simple calculations. under the new system they needed to understand only the four rules of arithmetic; indeed, so far as possible airy arranged his calculations in such a way that subtraction and division were rarely required. his boys had little more to do than add and multiply. thus, so far as the doing of work was concerned, he introduced the same sort of improvement that our times have witnessed in great manufacturing establishments, where labor is so organized that unskilled men bring about results that formerly demanded a high grade of technical ability. he introduced production on a large scale into astronomy. at the time of my visit, it was much the fashion among astronomers elsewhere to speak slightingly of the greenwich system. the objections to it were, in substance, the same that have been made to the minute subdivision of labor. the intellect of the individual was stunted for the benefit of the work. the astronomer became a mere operative. yet it must be admitted that the astronomical work done at greenwich during the sixty years since airy introduced his system has a value and an importance in its specialty that none done elsewhere can exceed. all future conclusions as to the laws of motion of the heavenly bodies must depend largely upon it. the organization of his little army necessarily involved a corresponding change in the instruments they were to use. before his time the trained astronomer worked with instruments of very delicate construction, so that skill in handling them was one of the requisites of an observer. airy made them in the likeness of heavy machinery, which could suffer no injury from a blow of the head of a careless observer. strong and simple, they rarely got out of order. it is said that an assistant who showed a visiting astronomer the transit circle some times hit it a good slap to show how solid it was; but this was not done on the present occasion. the little army had its weekly marching orders and made daily reports of progress to its commander, who was thus enabled to control the minutest detail of every movement. in the course of the evening airy gave me a lesson in method, which was equally instructive and entertaining. in order to determine the longitude of gibraltar, it was necessary that time signals should be sent by telegraph from the royal observatory. our conversation naturally led us into a discussion of the general subject of such operations. i told him of the difficulties we had experienced in determining a telegraphic longitude,--that of the harvard observatory from washington, for example,--because it was only after a great deal of talking and arranging on the evening of the observation that the various telegraph stations between the two points could have their connections successfully made at the same moment. at the appointed hour the washington operator would be talking with the others, to know if they were ready, and so a general discussion about the arrangements might go on for half an hour before the connections were all reported good. if we had such trouble in a land line, how should we get a connection from london to the gibraltar cable through lines in constant use? "but," said airy, "i never allow an operator who can speak with the instruments to take part in determining a telegraphic longitude." "then how can you get the connections all made from one end of the line to the other, at the same moment, if your operators cannot talk to one another?" "nothing is simpler. i fix in advance a moment, say eight o'clock greenwich mean time, at which signals are to commence. every intermediate office through which the signals are to pass is instructed to have its wires connected in both directions exactly at the given hour, and to leave them so connected for ten minutes, without asking any further instructions. at the end of the line the instruments must be prepared at the appointed hour to receive the signals. all i have to do here is to place my clock in the circuit and send on the signals for ten minutes, commencing at eight o'clock. they are recorded at the other end of the line without further trouble." "but have you never met with a failure to understand the instructions?" "no; they are too simple to be mistaken, once it is understood that no one has anything to do but make his connections at the designated moment, without asking whether any one else is ready." airy was noted not less for his ability as an organizer than for his methodical habits. the care with which he preserved every record led sir william rowan hamilton to say that when airy wiped his pen on a blotter, he fancied him as always taking a press copy of the mark. his machinery seemed to work perfectly, whether it was constructed of flesh or of brass. he could prepare instructions for the most complicated piece of work with such effective provision against every accident and such completeness in every detail that the work would go on for years without further serious attention from him. the instruments which he designed half a century ago are mostly in use to this day, with scarcely an alteration. yet there is some reason to fear that airy carried method a little too far to get the best results. of late years his system has been greatly changed, even at greenwich. it was always questionable whether so rigid a military routine could accomplish the best that was possible in astronomy; and airy himself, during his later years, modified his plan by trying to secure trained scientific men as his assistants, giving them liberty to combine independent research, on their own account, with the work of the establishment. his successor has gone farther in the same direction, and is now gathering around him a corps of young university men, from whose ability much may be expected. observations with the spectroscope have been pursued, and the observatory has taken a prominent part in the international work of making a photographic map of the heavens. of special importance are the regular discussions of photographs of the sun, taken in order to determine the law of the variation of the spots. the advantage of the regular system which has been followed for more than fifty years is seen in the meteorological observations; these disprove some theories of the relation between the sun and the weather, in a way that no other set of meteorological records has done. while delicate determinations of the highest precision, such as those made at pulkova, are not yet undertaken to any great extent, a regular even if slow improvement is going on in the general character of the observations and researches, which must bear fruit in due time. one of the curious facts we learned at greenwich was that astronomy was still supposed to be astrology by many in england. that a belief in astrology should survive was perhaps not remarkable, though i do not remember to have seen any evidence of it in this country. but applications received at the royal observatory, from time to time, showed a widespread belief among the masses that one of the functions of the astronomer royal was the casting of horoscopes. we went to edinburgh. our first visit was to the observatory, then under the direction of professor c. piazzi smyth, who was also an egyptologist of repute, having made careful measurements of the pyramids, and brought out some new facts regarding their construction. he was thus led to the conclusion that they bore marks of having been built by a people of more advanced civilization than was generally supposed,--so advanced, indeed, that we had not yet caught up to them in scientific investigation. these views were set forth with great fullness in his work on "the antiquity of intellectual man," as well as in other volumes describing his researches. he maintained that the builders of the pyramids knew the distance of the sun rather better than we did, and that the height of the great pyramid had been so arranged that if it was multiplied by a thousand millions we should get this distance more exactly than we could measure it in these degenerate days. with him, to believe in the pyramid was to believe this, and a great deal more about the civilization which it proved. so, when he asked me whether i believed in the pyramid, i told him that i did not think i would depend wholly upon the pyramid for the distance of the sun to be used in astronomy, but should want its indications at least confirmed by modern researches. the hint was sufficient, and i was not further pressed for views on this subject. he introduced us to lady hamilton, widow of the celebrated philosopher, who still held court at edinburgh. the daughter of the family was in repute as a metaphysician. this was interesting, because i had never before heard of a female metaphysician, although there were several cases of female mathematicians recorded in history. first among them was donna maria agnesi, who wrote one of the best eighteenth-century books on the calculus, and had a special dispensation from the pope to teach mathematics at bologna. we were therefore very glad to accept an invitation from lady hamilton to spend an evening with a few of her friends. her rooms were fairly filled with books, the legacy of one of whom it was said that "scarcely a thought has come down to us through the ages which he has not mastered and made his own." the few guests were mostly university people and philosophers. the most interesting of them was professor blackie, the grecian scholar, who was the liveliest little man of sixty i ever saw; amusing us by singing german songs, and dancing about the room like a sprightly child among its playmates. i talked with miss hamilton about mill, whose "examination of sir william hamilton's philosophy" was still fresh in men's minds. of course she did not believe in this book, and said that mill could not understand her father's philosophy. with all her intellect, she was a fine healthy-looking young lady, and it was a sad surprise, a few years later, to hear of her death. madame sophie kovalevsky afterward appeared on the stage as the first female mathematician of our time, but it may be feared that the woman philosopher died with miss hamilton. a large party of english astronomers were going to algeria to observe the eclipse. the government had fitted up a naval transport for their use, and as i was arranging for a passage on a ship of the peninsular and oriental line we received an invitation to become the guests of the english party. among those on board were professor tyndall; mr. huggins, the spectroscopist; sir erastus ommaney, a retired english admiral, and a fellow of the royal society; father perry, s. j., a well-known astronomer; and lieutenant wharton, who afterward became hydrographer to the admiralty. the sprightliest man on board was professor tyndall. he made up for the absence of mountains by climbing to every part of the ship he could reach. one day he climbed the shrouds to the maintop, and stood surveying the scene as if looking out from the top of the matterhorn. a sailor followed him, and drew a chalk-line around his feet. i assume the reader knows what this means; if he does not, he can learn by straying into the sailors' quarters the first time he is on board an ocean steamer. but the professor absolutely refused to take the hint. we had a rather rough passage, from which father perry was the greatest sufferer. one day he heard a laugh from the only lady on board, who was in the adjoining stateroom. "who can laugh at such a time as this!" he exclaimed. he made a vow that he would never go on the ocean again, even if the sun and moon fought for a month. but the vows of a seasick passenger are forgotten sooner than any others i know of; and it was only four years later that father perry made a voyage to kerguelen island, in the stormiest ocean on the globe, to observe a transit of venus. off the coast of spain, the leading chains of the rudder got loose, during a gale in the middle of the night, and the steering apparatus had to be disconnected in order to tighten them. the ship veered round into the trough of the sea, and rolled so heavily that a table, twenty or thirty feet long, in the saloon, broke from its fastenings, and began to dance around the cabin with such a racket that some of the passengers feared for the safety of the ship. just how much of a storm there was i cannot say, believing that it is never worth while for a passenger to leave his berth, if there is any danger of a ship foundering in a gale. but in professor tyndall's opinion we had a narrow escape. on arriving at gibraltar, he wrote a glowing account of the storm to the london times, in which he described the feelings of a philosopher while standing on the stern of a rolling ship in an ocean storm, without quite knowing whether she was going to sink or swim. the letter was anonymous, which gave admiral ommaney an excellent opportunity to write as caustic a reply as he chose, under the signature of "a naval officer." he said that sailor was fortunate who could arrange with the clerk of the weather never to have a worse storm in crossing the bay of biscay than the one we had experienced. we touched at cadiz, and anchored for a few hours, but did not go ashore. the brooklyn, an american man-of-war, was in the harbor, but there was no opportunity to communicate with her, though i knew a friend of mine was on board. gibraltar is the greatest babel in the world, or, at least, the greatest i know. i wrote home: "the principal languages spoken at this hotel are english, spanish, moorish, french, italian, german, and danish. i do not know what languages they speak at the other hotels." moorish and spanish are the local tongues, and of course english is the official one; but the traders and commercial travelers speak nearly every language one ever heard. i hired a moor--who bore some title which indicated that he was a descendant of the caliphs, and by which he had to be addressed--to do chores and act as general assistant. one of the first things i did, the morning after my arrival, was to choose a convenient point on one of the stone parapets for "taking the sun," in order to test the running of my chronometer. i had some suspicion as to the result, but was willing to be amused. a sentinel speedily informed me that no sights were allowed to be taken on the fortification. i told him i was taking sights on the sun, not on the fortification. but he was inexorable; the rule was that no sights of any sort could be taken without a permit. i soon learned from mr. sprague, the american consul, who the proper officer was to issue the permit, which i was assured would be granted without the slightest difficulty. the consul presented me to the military governor of the place, general sir fenwick williams of kars. i did not know till long afterward that he was born very near where i was. he was a man whom it was very interesting to meet. his heroic defense of the town whose name was added to his own as a part of his title was still fresh in men's minds. it had won him the order of the bath in england, the grand cross of the legion of honor and a sword from napoleon iii., and the usual number of lesser distinctions. the military governor, the sole authority and viceroy of the queen in the fortress, is treated with the deference due to an exalted personage; but this deference so strengthens the dignity of the position that the holder may be frank and hearty at his own pleasure, without danger of impairing it. certainly, we found sir fenwick a most genial and charming gentleman. the alabama claims were then in their acute stage, and he expressed the earnest hope that the two nations would not proceed to cutting each other's throats over them. there was no need of troubling the governor with such a detail as that of a permit to take sights; but the consul ventured to relate my experience of the morning. he took the information in a way which showed that england, in making him a general, had lost a good diplomatist. instead of treating the matter seriously, which would have implied that we did not fully understand the situation, he professed to be greatly amused, and said it reminded him of the case of an old lady in "punch" who had to pass a surveyor in the street, behind a theodolite. "please, sir, don't shoot till i get past," she begged. before leaving england, i had made very elaborate arrangements, both with the astronomer royal and with the telegraph companies, to determine the longitude of gibraltar by telegraphic signals. the most difficult part of the operation was the transfer of the signals from the end of the land line into the cable, which had to be done by hand, because the cable companies were not willing to trust to an automatic action of any sort between the land line and the cable. it was therefore necessary to show the operator at the point of junction how signals were to be transmitted. this required a journey to port curno, at the very end of the land's end, several miles beyond the terminus of the railway. it was the most old-time place i ever saw; one might have imagined himself thrown back into the days of the lancasters. the thatched inn had a hard stone floor, with a layer of loose sand scattered over it as a carpet in the bedroom. my linguistic qualities were put to a severe test in talking with the landlady. but the cable operators were pleasing and intelligent young gentlemen, and i had no difficulty in making them understand how the work was to be done. the manager of the cable was sir james anderson, who had formerly commanded a cunard steamship from boston, and was well known to the harvard professors, with whom he was a favorite. i had met him, or at least seen him, at a meeting of the american academy ten years before, where he was introduced by one of his harvard friends. after commanding the ship that laid the first atlantic cable, he was made manager of the cable line from england to gibraltar. he gave me a letter to the head operator at gibraltar, the celebrated de sauty. i say "the celebrated," but may it not be that this appellation can only suggest the vanity of all human greatness? it just occurs to me that many of the present generation may not even have heard of the- whispering boanerges, son of silent thunder, holding talk with nations, immortalized by holmes in one of his humorously scientific poems. during the two short weeks that the first atlantic cable transmitted its signals, his fame spread over the land, for the moment obscuring by its brilliancy that of thomson, field, and all others who had taken part in designing and laying the cable. on the breaking down of the cable he lapsed into his former obscurity. i asked him if he had ever seen holmes's production. he replied that he had received a copy of "the atlantic monthly" containing it from the poet himself, accompanied by a note saying that he might find in it something of interest. he had been overwhelmed with invitations to continue his journey from newfoundland to the united states and lecture on the cable, but was sensible enough to decline them. the rest of the story of the telegraphic longitude is short. the first news which de sauty had to give me was that the cable was broken,--just where, he did not know, and would not be able soon to discover. after the break was located, an unknown period would be required to raise the cable, find the place, and repair the breach. the weather, on the day of the eclipse, was more than half cloudy, so that i did not succeed in making observations of such value as would justify my waiting indefinitely for the repair of the cable, and the project of determining the longitude had to be abandoned. xi men and things in europe we went from gibraltar to berlin in january by way of italy. the mediterranean is a charming sea in summer, but in winter is a good deal like the atlantic. the cause of the blueness of its water is not completely settled; but its sharing this color with lake geneva, which is tinged with detritus from the shore, might lead one to ascribe it to substances held in solution. the color is noticeable even in the harbor of malta, to which we had a pleasant though not very smooth passage of five days. here was our first experience of an italian town of a generation ago. i had no sooner started to take a walk than a so-called guide, who spoke what he thought was english, got on my track, and insisted on showing me everything. if i started toward a shop, he ran in before me, invited me in, asked what i would like to buy, and told the shopman to show the gentleman something. i could not get rid of him till i returned to the hotel, and then he had the audacity to want a fee for his services. i do not think he got it. everything of interest was easily seen, and we only stopped to take the first italian steamer to messina. we touched at syracuse and catania, but did not land. ætna, from the sea, is one of the grandest sights i ever saw. its snow-covered cone seems to rise on all sides out of the sea or the plain, and to penetrate the blue sky. in this it gives an impression like that of the weisshorn seen from randa, but gains by its isolation. at messina, of course, our steamer was visited by a commissionnaire, who asked me in good english whether i wanted a hotel. i told him that i had already decided upon a hotel, and therefore did not need his services. but it turned out that he belonged to the very hotel i was going to, and was withal an american, a native-born yankee, in fact, and so obviously honest that i placed myself unreservedly in his hands,--something which i never did with one of his profession before or since. he said the first thing was to get our baggage through the custom-house, which he could do without any trouble, at the cost of a franc. he was as good as his word. the italian custom-house was marked by primitive rigor, and baggage was commonly subjected to a very thorough search. but my man was evidently well known and fully trusted. i was asked to raise the lid of one trunk, which i did; the official looked at it, with his hands in his pockets, gave a nod, and the affair was over. my yankee friend collected one franc for that part of the business. he told us all about the place, changed our money so as to take advantage of the premium on gold, and altogether looked out for our interests in a way to do honor to his tribe. i thought there might be some curious story of the way in which a new englander of such qualities could have dropped into such a place, but it will have to be left to imagination. we reached the bay of naples in the morning twilight, after making an unsuccessful attempt to locate scylla and charybdis. if they ever existed, they must have disappeared. vesuvius was now and then lighting up the clouds with its intermittent flame. but we had passed a most uncomfortable night, and the morning was wet and chilly. a view requires something more than the objective to make it appreciated, and the effect of a rough voyage and bad weather was such as to deprive of all its beauty what is considered one of the finest views in the world. moreover, the experience made me so ill-natured that i was determined that the custom-house officer at the landing should have no fee from me. the only article that could have been subject to duty was on top of everything in the trunk, except a single covering of some loose garment, so that only a touch was necessary to find it. when it came to the examination, the officer threw the top till contemptuously aside, and devoted himself to a thorough search of the bottom. the only unusual object he stumbled upon was a spyglass inclosed in a shield of morocco. perhaps a gesture and a remark on my part aroused his suspicions. he opened the glass, tried to take it to pieces, inspected it inside and out, and was so disgusted with his failure to find anything contraband in it that he returned everything to the trunk, and let us off. it is commonly and quite justly supposed that the more familiar the traveler is with the language of the place he visits, the better he will get along. it is a common experience to find that even when you can pronounce the language, you cannot understand what is said. but there are exceptions to all rules, and circumstances now and then occur in which one thus afflicted has an advantage over the native. you can talk to him, while he cannot talk to you. there was an amusing case of this kind at munich. the only train that would take us to berlin before nightfall of the same day left at eight o'clock in the morning, by a certain route. there was at munich what we call a union station. i stopped at the first ticket-office where i saw the word "berlin" on the glass, asked for a ticket good in the train that was going to leave at eight o'clock the next morning for berlin, and took what the seller gave me. he was a stupid-looking fellow, so when i got to my hotel i showed the ticket to a friend. "that is not the ticket that you want at all," said he; "it will take you by a circuitous route in a train that does not leave until after nine, and you will not reach berlin until long after dark." i went directly back to the station and showed my ticket to the agent. "i--asked--you--for--a--ticket--good--in--the--train--which-leaves--at--eight--o'--clock. this--ticket--is--not--good-in--that--train. sie--haben--mich--betrügen. i--want--you-to--take--the--ticket--back--and--return--me--the--money. what--you--say--can--i--not--understand." he expostulated, gesticulated, and fumed, but i kept up the bombardment until he had to surrender. he motioned to me to step round into the office, where he took the ticket and returned the money. i mention the matter because taking back a ticket is said to be quite unusual on a german railway. at berlin, the leading astronomers then, as now, were förster, director of the observatory, and auwers, permanent secretary of the academy of sciences. i was especially interested in the latter, as we had started in life nearly at the same time, and had done much work on similar lines. it was several days before i made his acquaintance, as i did not know that the rule on the continent is that the visitor must make the first call, or at least make it known by direct communication that he would be pleased to see the resident; otherwise it is presumed that he does not wish to see callers. this is certainly the more logical system, but it is not so agreeable to the visiting stranger as ours is. the art of making the latter feel at home is not brought to such perfection on the continent as in england; perhaps the french understand it less than any other people. but none can be pleasanter than the germans, when you once make their acquaintance; and we shall always remember with pleasure the winter we passed in berlin. to-day, auwers stands at the head of german astronomy. in him is seen the highest type of the scientific investigator of our time, one perhaps better developed in germany than in any other country. the work of men of this type is marked by minute and careful research, untiring industry in the accumulation of facts, caution in propounding new theories or explanations, and, above all, the absence of effort to gain recognition by being the first to make a discovery. when men are ambitious to figure as newtons of some great principle, there is a constant temptation to publish unverified speculations which are likely rather to impede than to promote the advance of knowledge. the result of auwers's conscientiousness is that, notwithstanding his eminence in his science, there are few astronomers of note whose works are less fitted for popular exposition than his. his specialty has been the treatment of all questions concerning the positions and motions of the stars. this work has required accurate observations of position, with elaborate and careful investigations of a kind that offer no feature to attract public attention, and only in exceptional cases lead to conclusions that would interest the general reader. he considers no work as ready for publication until it is completed in every detail. the old astronomical observations of which i was in quest might well have been made by other astronomers than those of paris, so while awaiting the end of the war i tried to make a thorough search of the writings of the mediæval astronomers in the royal library. if one knew exactly what books he wanted, and had plenty of time at his disposal, he would find no difficulty in consulting them in any of the great continental libraries. but at the time of my visit, notwithstanding the cordiality with which all the officials, from professor lepsius down, were disposed to second my efforts, the process of getting any required book was very elaborate. although one could obtain a book on the same day he ordered it, if he went in good time, it was advisable to leave the order the day before, if possible. when, as in the present case, one book only suggests another, this a third, and so on, in an endless chain, the carrying on of an extended research is very tedious. one feature of the library strongly impressed me with the comparatively backward state of mathematical science in our own country. as is usual in the great european libraries, those books which are most consulted are placed in the general reading-room, where any one can have access to them, at any moment. it was surprising to see amongst these books a set of crelle's "journal of mathematics," and to find it well worn by constant use. at that time, so far as i could learn, there were not more than two or three sets of the journal in the united states; and these were almost unused. even the library of congress did not contain a set. there has been a great change since that time,--a change in which the johns hopkins university took the lead, by inviting sylvester to this country, and starting a mathematical school of the highest grade. other universities followed its example to such an extent that, to-day, an american student need not leave his own country to hear a master in any branch of mathematics. i believe it was dr. b. a. gould who called the pulkova observatory the astronomical capital of the world. this institution was founded in 1839 by the emperor nicholas, on the initiative of his greatest astronomer. it is situated some twelve miles south of st. petersburg, not far from the railway between that city and berlin, and gets its name from a peasant village in the neighborhood. from its foundation it has taken the lead in exact measurements relating to the motion of the earth and the positions of the principal stars. an important part of its equipment is an astronomical library, which is perhaps the most complete in existence. this, added to all its other attractions, induced me to pay a visit to pulkova. otto struve, the director, had been kind enough to send me a message, expressing the hope that i would pay him a visit, and giving directions about telegraphing in advance, so as to insure the delivery of the dispatch. the time from berlin to st. petersburg is about forty-eight hours, the only through train leaving and arriving in the evening. on the morning of the day that the train was due i sent the dispatch. early in the afternoon, as the train was stopping at a way station, i saw an official running hastily from one car to another, looking into each with some concern. when he came to my door, he asked if i had sent a telegram to estafetta. i told him i had. he then informed me that estafetta had not received it. but the train was already beginning to move, so there was no further chance to get information. the comical part of the matter was that "estafetta" merely means a post or postman, and that the directions, as struve had given them, were to have the dispatch sent by postman from the station to pulkova. it was late in the evening when the train reached zarsko-selo, the railway station for pulkova, which is about five miles away. the station-master told me that no carriage from pulkova was waiting for me, which tended to confirm the fear that the dispatch had not been received. after making known my plight, i took a seat in the station and awaited the course of events, in some doubt what to do. only a few minutes had elapsed when a good-looking peasant, well wrapped in a fur overcoat, with a whip in his hand, looked in at the door, and pronounced very distinctly the words, "observatorio pulkova." ah! this is struve's driver at last, thought i, and i followed the man to the door. but when i looked at the conveyance, doubt once more supervened. it was scarcely more than a sledge, and was drawn by a single horse, evidently more familiar with hard work than good feeding. this did not seem exactly the vehicle that the great russian observatory would send out to meet a visitor; yet it was a far country, and i was not acquainted with its customs. the way in which my doubt was dispelled shows that there is one subject besides love on which difference of language is no bar to the communication of ideas. this is the desire of the uncivilized man for a little coin of the realm. in south africa, zulu chiefs, who do not know one other word of english, can say "shilling" with unmistakable distinctness. my russian driver did not know even this little english word, but he knew enough of the universal language. when we had made a good start on the snow-covered prairie, he stopped his horse for a moment, looked round at me inquiringly, raised his hand, and stretched out two fingers so that i could see them against the starlit sky. i nodded assent. then he drew his overcoat tightly around him with a gesture of shivering from the cold, beat his hands upon his breast as if to warm it, and again looked inquiringly at me. i nodded again. the bargain was complete. he was to have two rubles for the drive, and a little something to warm up his shivering breast. so he could not be struve's man. there is no welcome warmer than a russian one, and none in any country warmer than that which the visiting astronomer receives at an observatory. great is the contrast between the winter sky of a clear moonless night and the interior of a dining-room, forty feet square, with a big blazing fire at one end and a table loaded with eatables in the middle. the fact that the visitor had never before met one of his hosts detracted nothing from the warmth of his reception. the organizer of the observatory, and its first director, was wilhelm struve, father of the one who received me, and equally great as man and astronomer. like many other good russians, he was the father of a large family. one of his sons was for ten years the russian minister at washington, and as popular a diplomatist as ever lived among us. the instruments which struve designed sixty years ago still do as fine work as any in the world; but one may suspect this to be due more to the astronomers who handle them than to the instruments themselves. the air is remarkably clear; the entrance to st. petersburg, ten or twelve miles north, is distinctly visible, and struve told me that during the crimean war he could see, through the great telescope, the men on the decks of the british ships besieging kronstadt, thirty miles away. one drawback from which the astronomers suffer is the isolation of the place. the village at the foot of the little hill is inhabited only by peasants, and the astronomers and employees have nearly all to be housed in the observatory buildings. there is no society but their own nearer than the capital. at the time of my visit the scientific staff was almost entirely german or swedish, by birth or language. in the state, two opposing parties are the russian, which desires the ascendency of the native muscovites, and the german, which appreciates the fact that the best and most valuable of the tsar's subjects are of german or other foreign descent. during the past twenty years the russian party has gradually got the upper hand; and the result of this ascendency at pulkova will be looked for with much solicitude by astronomers everywhere. once a year the lonely life of the astronomers is enlivened by a grand feast--that of the russian new year. one object of the great dining-room which i have mentioned, the largest room, i believe, in the whole establishment, was to make this feast possible. my visit took place early in march, so that i did not see the celebration; but from what i have heard, the little colony does what it can to make up for a year of ennui. every twenty-five years it celebrates a jubilee; the second came off in 1889. there is much to interest the visitor in a russian peasant village, and that of pulkova has features some of which i have never seen described. above the door of each log hut is the name of the occupant, and below the name is a rude picture of a bucket, hook, or some other piece of apparatus used in extinguishing fire. inside, the furniture is certainly meagre enough, yet one could not see why the occupants should be otherwise than comfortable. i know of no good reason why ignorance should imply unhappiness; altogether, there is some good room for believing that the less civilized races can enjoy themselves, in their own way, about as well as we can. what impressed me as the one serious hardship of the peasantry was their hours of labor. just how many hours of the twenty-four these beings find for sleep was not clear to the visitor; they seemed to be at work all day, and at midnight many of them had to start on their way to st. petersburg with a cartload for the market. a church ornamented with tinsel is a feature of every russian village; so also are the priests. the only two i saw were sitting on a fence, wearing garments that did not give evidence of having known water since they were made. one great drawback to the growth of manufactures in russia is the number of feast days, on which the native operators must one and all abandon their work, regardless of consequences. the astronomical observations made at pulkova are not published annually, as are those made at most of the other national observatories; but a volume relating to one subject is issued whenever the work is done. when i was there, the volumes containing the earlier meridian observations were in press. struve and his chief assistant, dr. wagner, used to pore nightly over the proof sheets, bestowing on every word and detail a minute attention which less patient astronomers would have found extremely irksome. dr. wagner was a son-in-law of hansen, the astronomer of the little ducal observatory at gotha, as was also our bayard taylor. my first meeting with hansen, which occurred after my return to berlin, was accompanied with some trepidation. modest as was the public position that he held, he may now fairly be considered the greatest master of celestial mechanics since laplace. in what order leverrier, delaunay, adams, and hill should follow him, it is not necessary to decide. to many readers it will seem singular to place any name ahead of that of the master who pointed out the position of neptune before a human eye had ever recognized it. but this achievement, great as it was, was more remarkable for its boldness and brilliancy than for its inherent difficulty. if the work had to be done over again to-day, there are a number of young men who would be as successful as leverrier; but there are none who would attempt to reinvent the methods of hansen, or even to improve radically upon them. their main feature is the devising of new and refined methods of computing the variations in the motions of a planet produced by the attraction of all the other planets. as laplace left this subject, the general character of these variations could be determined without difficulty, but the computations could not be made with mathematical exactness. hansen's methods led to results so precise that, if they were fully carried out, it is doubtful whether any deviation between the predicted and the observed motions of a planet could be detected by the most refined observation. at the time of my visit mrs. wagner was suffering from a severe illness, of which the crisis passed while i was at pulkova, and left her, as was supposed, on the road to recovery. i was, of course, very desirous of meeting so famous a man as hansen. he was expected to preside at a session of the german commission on the transit of venus, which was to be held in berlin about the time of my return thither from pulkova. the opportunity was therefore open of bringing a message of good news from his daughter. apart from this, the prospect of the meeting might have been embarrassing. the fact is that i was at odds with him on a scientific question, and he was a man who did not take a charitable view of those who differed from him in opinion. he was the author of a theory, current thirty or forty years ago, that the farther side of the moon is composed of denser materials than the side turned toward us. as a result of this, the centre of gravity of the moon was supposed to be farther from us than the actual centre of her globe. it followed that, although neither atmosphere nor water existed on our side of the moon, the other side might have both. here was a very tempting field into which astronomical speculators stepped, to clothe the invisible hemisphere of the moon with a beautiful terrestrial landscape, and people it as densely as they pleased with beings like ourselves. if these beings should ever attempt to explore the other half of their own globe, they would find themselves ascending to a height completely above the limits of their atmosphere. hansen himself never countenanced such speculations as these, but confined his claims to the simple facts he supposed proven. in 1868 i had published a little paper showing what i thought a fatal defect, a vicious circle in fact, in hansen's reasoning on this subject. not long before my visit, delaunay had made this paper the basis of a communication to the french academy of sciences, in which he not only indorsed my views, but sought to show the extreme improbability of hansen's theory on other grounds. when i first reached germany, on my way from italy, i noticed copies of a blue pamphlet lying on the tables of the astronomers. apparently, the paper had been plentifully distributed; but it was not until i reached berlin that i found it was hansen's defense against my strictures,--a defense in which mathematics were not unmixed with seething sarcasm at the expense of both delaunay and myself. the case brought to mind a warm discussion between hansen and encke, in the pages of a scientific journal, some fifteen years before. at the time it had seemed intensely comical to see two enraged combatants--for so i amused myself by fancying them--hurling algebraic formulæ, of frightful complexity, at each other's heads. i did not then dream that i should live to be an object of the same sort of attack, and that from hansen himself. to be revised, pulled to pieces, or superseded, as science advances, is the common fate of most astronomical work, even the best. it does not follow that it has been done in vain; if good, it forms a foundation on which others will build. but not every great investigator can look on with philosophic calm when he sees his work thus treated, and hansen was among the last who could. under these circumstances, it was a serious question what sort of reception hansen would accord to a reviser of his conclusions who should venture to approach him. i determined to assume an attitude that would show no consciousness of offense, and was quite successful. our meeting was not attended by any explosion; i gave him the pleasant message with which i was charged from his daughter, and, a few days later, sat by his side at a dinner of the german commission on the coming transit of venus. as hansen was germany's greatest master in mathematical astronomy, so was the venerable argelander in the observational side of the science. he was of the same age as the newly crowned emperor, and the two were playmates at the time germany was being overrun by the armies of napoleon. he was held in love and respect by the entire generation of young astronomers, both germans and foreigners, many of whom were proud to have had him as their preceptor. among these was dr. b. a. gould, who frequently related a story of the astronomer's wit. when with him as a student, gould was beardless, but had a good head of hair. returning some years later, he had become bald, but had made up for it by having a full, long beard. he entered argelander's study unannounced. at first the astronomer did not recognize him. "do you not know me, herr professor?" the astronomer looked more closely. "mine gott! it is gould mit his hair struck through!" argelander was more than any one else the founder of that branch of his science which treats of variable stars. his methods have been followed by his successors to the present time. it was his policy to make the best use he could of the instruments at his disposal, rather than to invent new ones that might prove of doubtful utility. the results of his work seem to justify this policy. we passed the last month of the winter in berlin waiting for the war to close, so that we could visit paris. poor france had at length to succumb, and in the latter part of march, we took almost the first train that passed the lines. delaunay was then director of the paris observatory, having succeeded leverrier when the emperor petulantly removed the latter from his position. i had for some time kept up an occasional correspondence with delaunay, and while in england, the autumn before, had forwarded a message to him, through the prussian lines, by the good offices of the london legation and mr. washburn. he was therefore quite prepared for our arrival. the evacuation of a country by a hostile army is rather a slow process, so that the german troops were met everywhere on the road, even in france. they had left paris just before we arrived; but the french national army was not there, the communists having taken possession of the city as fast as the germans withdrew. as we passed out of the station, the first object to strike our eyes was a flaming poster addressed to "citoyens," and containing one of the manifestoes which the communist government was continually issuing. of course we made an early call on mr. washburn. his career in paris was one of the triumphs of diplomacy; he had cared for the interests of german subjects in paris in such a way as to earn the warm recognition both of the emperor and of bismarck, and at the same time had kept on such good terms with the french as to be not less esteemed by them. he was surprised that we had chosen such a time to visit paris; but i told him the situation, the necessity of my early return home, and my desire to make a careful search in the records of the paris observatory for observations made two centuries ago. he advised us to take up our quarters as near to the observatory as convenient, in order that we might not have to pass through the portions of the city which were likely to be the scenes of disturbance. we were received at the observatory with a warmth of welcome that might be expected to accompany the greeting of the first foreign visitor, after a siege of six months. yet a tinge of sadness in the meeting was unavoidable. delaunay immediately began lamenting the condition of his poor ruined country, despoiled of two of its provinces by a foreign foe, condemned to pay an enormous subsidy in addition, and now the scene of an internal conflict the end of which no one could foresee. while i was mousing among the old records of the paris observatory, the city was under the reign of the commune and besieged by the national forces. the studies had to be made within hearing of the besieging guns; and i could sometimes go to a window and see flashes of artillery from one of the fortifications to the south. nearly every day i took a walk through the town, occasionally as far as the arc de triomphe. the story of the commune has been so often written that i cannot hope to add anything to it, so far as the main course of events is concerned. looking back on a sojourn at so interesting a period, one cannot but feel that a golden opportunity to make observations of historic value was lost. the fact is, however, that i was prevented from making such observations not only by my complete absorption in my work, but by the consideration that, being in what might be described as a semi-official capacity, i did not want to get into any difficulty that would have compromised the position of an official visitor. i should not deem what we saw worthy of special mention, were it not that it materially modifies the impressions commonly given by writers on the history of the commune. what an historian says may be quite true, so far as it goes, and yet may be so far from the whole truth as to give the reader an incorrect impression of the actual course of events. the violence and disease which prevail in the most civilized country in the world may be described in such terms as to give the impression of a barbarous community. the murder of the archbishop of paris and of the hostages show how desperate were the men who had seized power, yet the acts of these men constitute but a small part of the history of paris during that critical period. what one writes at the time is free from the suspicion that may attach to statements not recorded till many years after the events to which they relate. the following extract from a letter which i wrote to a friend, the day after my arrival, may therefore be taken to show how things actually looked to a spectator:- dear charlie,--here we are, on this slumbering volcano. perhaps you will hear of the burst-up long before you get this. we have seen historic objects which fall not to the lot of every generation, the barricades of the paris streets. as we were walking out this morning, the pavement along one side of the street was torn up for some distance, and used to build a temporary fort. said fort would be quite strong against musketry or the bayonet; but with heavy shot against it, i should think it would be far worse than nothing, for the flying stones would kill more than the balls. the streets are placarded at every turn with all sorts of inflammatory appeals, and general orders of the comité central or of the commune. one of the first things i saw last night was a large placard beginning "citoyens!" among the orders is one forbidding any one from placarding any orders of the versailles government under the severest penalties; and another threatening with instant dismissal any official who shall recognize any order issuing from the said government. i must do all hands the justice to say that they are all very well behaved. there is nothing like a mob anywhere, so far as i can find. i consulted my map this morning, right alongside the barricade and in full view of the builders, without being molested, and wife and i walked through the insurrectionary districts without being troubled or seeing the slightest symptoms of disturbance. the stores are all open, and every one seems to be buying and selling as usual. in all the cafés i have seen, the habitués seem to be drinking their wine just as coolly as if they had nothing unusual on their minds. from this date to that of our departure i saw nothing suggestive of violence within the limited range of my daily walks, which were mostly within the region including the arc de triomphe, the hôtel de ville, and the observatory; the latter being about half a mile south of the luxembourg. the nearest approach to a mob that i ever noticed was a drill of young recruits of the national guard, or a crowd in the court of the louvre being harangued by an orator. with due allowance for the excitability of the french nature, the crowd was comparatively as peaceable as that which we may see surrounding a gospel wagon in one of our own cities. a drill-ground for the recruits happened to be selected opposite our first lodgings, beside the gates of the luxembourg. this was so disagreeable that we were glad to accept an invitation from delaunay to be his guests at the observatory, during the remainder of our stay. we had not been there long before the spacious yard of the observatory was also used as a drill-ground; and yet later, two or three men were given _billets de logement_ upon the observatory; but i should not have known of the latter occurrence, had not delaunay told me. i believe he bought the men off, much as one pays an organ-grinder to move on. in one of our walks we entered the barricade around the hôtel de ville, and were beginning to make a close examination of a mitrailleuse, when a soldier (beg his pardon, _un citoyen membre de la garde nationale_) warned us away from the weapon. the densest crowd of communists was along the rue de rivoli and in the region of the colonne vendôme, where some of the principal barricades were being erected. but even here, not only were the stores open as usual, but the military were doing their work in the midst of piles of trinkets exposed for sale on the pavement by the shopwomen. the order to destroy the column was issued before we left, but not executed until later. i have no reason to suppose that the shopwomen were any more concerned while the column was being undermined than they were before. to complete the picture, not a policeman did we see in paris; in fact, i was told that one of the first acts of the commune had been to drive the police away, so that not one dared to show himself. an interesting feature of the sad spectacle was the stream of proclamations poured forth by the communist authorities. they comprised not only decrees, but sensational stories of victories over the versailles troops, denunciations of the versailles government, and even elaborate legal arguments, including a not intemperate discussion of the ethical question whether citizens who were not adherents of the commune should be entitled to the right of suffrage. the conclusion was that they should not. the lack of humor on the part of the authorities was shown by their commencing one of a rapid succession of battle stories with the words, "citoyens! vous avez soif de la vérité!" the most amusing decree i noticed ran thus:-"article i. all conscription is abolished. "article ii. no troops shall hereafter be allowed in paris, except the national guard. "article iii. every citizen is a member of the national guard." we were in daily expectation and hope of the capture of the city, little imagining by what scenes it would be accompanied. it did not seem to my unmilitary eye that two or three batteries of artillery could have any trouble in demolishing all the defenses, since a wall of paving-stones, four or five feet high, could hardly resist solid shot, or prove anything but a source of destruction to those behind it if attacked by artillery. but the capture was not so easy a matter as i had supposed. we took leave of our friend and host on may 5, three weeks before the final catastrophe, of which he wrote me a graphic description. as the barricades were stormed by macmahon, the communist line of retreat was through the region of the observatory. the walls of the building and of the yard were so massive that the place was occupied as a fort by the retreating forces, so that the situation of the few non-combatants who remained was extremely critical. they were exposed to the fire of their friends, the national troops, from without, while enraged men were threatening their lives within. so hot was the fusillade that, going into the great dome after the battle, the astronomer could imagine all the constellations of the sky depicted by the bullet-holes. when retreat became inevitable, the communists tried to set the building on fire, but did not succeed. then, in their desperation, arrangements were made for blowing it up; but the most violent man among them was killed by a providential bullet, as he was on the point of doing his work. the remainder fled, the place was speedily occupied by the national troops, and the observatory with its precious contents was saved. the academy of sciences had met regularly through the entire prussian siege. the legal quorum being three, this did not imply a large attendance. the reason humorously assigned for this number was that, on opening a session, the presiding officer must say, _messieurs, la séance est ouverte_, and he cannot say _messieurs_ unless there are at least two to address. at the time of my visit a score of members were in the city. among them were elie de beaumont, the geologist; milne-edwards, the zoölogist; and chevreul, the chemist. i was surprised to learn that the latter was in his eighty-fifth year; he seemed a man of seventy or less, mentally and physically. yet we little thought that he would be the longest-lived man of equal eminence that our age has known. when he died, in 1889, he was nearly one hundred and three years old. born in 1786, he had lived through the whole french revolution, and was seven years old at the time of the terror. his scientific activity, from beginning to end, extended over some eighty years. when i saw him, he was still very indignant at a bombardment of the jardin des plantes by the german besiegers. he had made a formal statement of this outrage to the academy of sciences, in order that posterity might know what kind of men were besieging paris. i suggested that the shells might have fallen in the place by accident; but he maintained that it was not the case, and that the bombardment was intentional. the most execrated man in the scientific circle at this time was leverrier. he had left paris before the prussian siege began, and had not returned. delaunay assured me that this was a wise precaution on his part; for had he ventured into the city he would have been mobbed, or the communists would have killed him as soon as caught. just why the mob should have been so incensed against one whose life was spent in the serenest fields of astronomical science was not fully explained. the fact that he had been a senator, and was politically obnoxious, was looked on as an all-sufficient indictment. even members of the academy could not suppress their detestation of him. their language seemed not to have words that would fully express their sense of his despicable meanness, not to say turpitude. four years later i was again in paris, and attended a meeting of the academy of sciences. in the course of the session a rustle of attention spread over the room, as all eyes were turned upon a member who was entering rather late. looking toward the door, i saw a man of sixty, a decided blond, with light chestnut hair turning gray, slender form, shaven face, rather pale and thin, but very attractive, and extremely intellectual features. as he passed to his seat hands were stretched out on all sides to greet him, and not until he sat down did the bustle caused by his entrance subside. he was evidently a notable. "who is that?" i said to my neighbor. "leverrier." delaunay was one of the most kindly and attractive men i ever met. we spent our evenings walking in the grounds of the observatory, discussing french science in all its aspects. his investigation of the moon's motion is one of the most extraordinary pieces of mathematical work ever turned out by a single person. it fills two quarto volumes, and the reader who attempts to go through any part of the calculations will wonder how one man could do the work in a lifetime. his habit was to commence early in the morning, and work with but little interruption until noon. he never worked in the evening, and generally retired at nine. i felt some qualms of conscience at the frequency with which i kept him up till nearly ten. i found it hopeless to expect that he would ever visit america, because he assured me that he did not dare to venture on the ocean. the only voyage he had ever made was across the channel, to receive the gold medal of the royal astronomical society for his work. two of his relatives--his father and, i believe, his brother--had been drowned, and this fact gave him a horror of the water. he seemed to feel somewhat like the clients of the astrologists, who, having been told from what agencies they were to die, took every precaution to avoid them. i remember, as a boy, reading a history of astrology, in which a great many cases of this sort were described; the peculiarity being that the very measures which the victim took to avoid the decree of fate became the engines that executed it. the death of delaunay was not exactly a case of this kind, yet it could not but bring it to mind. he was at cherbourg in the autumn of 1872. as he was walking on the beach with a relative, a couple of boatmen invited them to take a sail. through what inducement delaunay was led to forget his fears will never be known. all we know is that he and his friend entered the boat, that it was struck by a sudden squall when at some distance from the land, and that the whole party were drowned. there was no opposition to the reappointment of leverrier to his old place. in fact, at the time of my visit, delaunay said that president thiers was on terms of intimate friendship with the former director, and he thought it not at all unlikely that the latter would succeed in being restored. he kept the position with general approval till his death in 1877. the only occasion on which i met leverrier was after the incident i have mentioned, in the academy of sciences. i had been told that he was incensed against me on account of an unfortunate remark i had made in speaking of his work which led to the discovery of neptune. i had heard this in germany as well as in france, yet the matter was so insignificant that i could hardly conceive of a man of philosophic mind taking any notice of it. i determined to meet him, as i had met hansen, with entire unconsciousness of offense. so i called on him at the observatory, and was received with courtesy, but no particular warmth. i suggested to him that now, as he had nearly completed his work on the tables of the planets, the question of the moon's motion would be the next object worthy of his attention. he replied that it was too large a subject for him to take up. to leverrier belongs the credit of having been the real organizer of the paris observatory. his work there was not dissimilar to that of airy at greenwich; but he had a much more difficult task before him, and was less fitted to grapple with it. when founded by louis xiv. the establishment was simply a place where astronomers of the academy of sciences could go to make their observations. there was no titular director, every man working on his own account and in his own way. cassini, an italian by birth, was the best known of the astronomers, and, in consequence, posterity has very generally supposed he was the director. that he failed to secure that honor was not from any want of astuteness. it is related that the monarch once visited the observatory to see a newly discovered comet through the telescope. he inquired in what direction the comet was going to move. this was a question it was impossible to answer at the moment, because both observations and computations would be necessary before the orbit could be worked out. but cassini reflected that the king would not look at the comet again, and would very soon forget what was told him; so he described its future path in the heavens quite at random, with entire confidence that any deviation of the actual motion from his prediction would never be noted by his royal patron. one of the results of this lack of organization has been that the paris observatory does not hold an historic rank correspondent to the magnificence of the establishment. the go-as-you-please system works no better in a national observatory than it would in a business institution. up to the end of the last century, the observations made there were too irregular to be of any special importance. to remedy this state of things, arago was appointed director early in the present century; but he was more eminent in experimental physics than in astronomy, and had no great astronomical problem to solve. the result was that while he did much to promote the reputation of the observatory in the direction of physical investigation, he did not organize any well-planned system of regular astronomical work. when leverrier succeeded arago, in 1853, he had an extremely difficult problem before him. by a custom extending through two centuries, each astronomer was to a large extent the master of his own work. leverrier undertook to change all this in a twinkling, and, if reports are true, without much regard to the feelings of the astronomers. those who refused to fall into line either resigned or were driven away, and their places were filled with men willing to work under the direction of their chief. yet his methods were not up to the times; and the work of the paris observatory, so far as observations of precision go, falls markedly behind that of greenwich and pulkova. in recent times the institution has been marked by an energy and a progressiveness that go far to atone for its former deficiencies. the successors of leverrier have known where to draw the line between routine, on the one side, and initiative on the part of the assistants, on the other. probably no other observatory in the world has so many able and well-trained young men, who work partly on their own account, and partly in a regular routine. in the direction of physical astronomy the observatory is especially active, and it may be expected in the future to justify its historic reputation. xii the old and the new washington a few features of washington as it appeared during the civil war are indelibly fixed in my memory. an endless train of army wagons ploughed its streets with their heavy wheels. almost the entire southwestern region, between the war department and the potomac, extending west on the river to the neighborhood of the observatory, was occupied by the quartermaster's and subsistence departments for storehouses. among these the astronomers had to walk by day and night, in going to and from their work. after a rain, especially during winter and spring, some of the streets were much like shallow canals. under the attrition of the iron-bound wheels the water and clay were ground into mud, which was at first almost liquid. it grew thicker as it dried up, until perhaps another rainstorm reduced it once more to a liquid condition. in trying first one street and then another to see which offered the fewest obstacles to his passage, the wayfarer was reminded of the assurance given by a bright boy to a traveler who wanted to know the best road to a certain place: "whichever road you take, before you get halfway there you'll wish you had taken t' other." by night swarms of rats, of a size proportional to their ample food supply, disputed the right of way with the pedestrian. across the potomac, arlington heights were whitened by the tents of soldiers, from which the discharges of artillery or the sound of the fife and drum became so familiar that the dweller almost ceased to notice it. the city was defended by a row of earthworks, generally not far inside the boundary line of the district of columbia, say five or six miles from the central portions of the city. one of the circumstances connected with their plans strikingly illustrates the exactness which the science or art of military engineering had reached. of course the erection of fortifications was one of the first tasks to be undertaken by the war department. plans showing the proposed location and arrangements of the several forts were drawn up by a board of army engineers, at whose head, then or afterward, stood general john g. barnard. when the plans were complete, it was thought advisable to test them by calling in the advice of professor d. h. mahan of the military academy at west point. he came to washington, made a careful study of the maps and plans, and was then driven around the region of the lines to be defended to supplement his knowledge by personal inspection. then he laid down his ideas as to the location of the forts. there were but two variations from the plans proposed by the board of engineers, and these were not of fundamental importance. willard's hotel, then the only considerable one in the neighborhood of the executive offices, was a sort of headquarters for arriving army officers, as well as for the thousands of civilians who had business with the government, and for gossip generally. inside its crowded entrance one could hear every sort of story, of victory or disaster, generally the latter, though very little truth was ever to be gleaned. the newsboy flourished. he was a bright fellow too, and may have developed into a man of business, a reporter, or even an editor. "another great battle!" was his constant cry. but the purchaser of his paper would commonly read of nothing but a skirmish or some fresh account of a battle fought several days before--perhaps not even this. on one occasion an officer in uniform, finding nothing in his paper to justify the cry, turned upon the boy with the remark,-"look here, boy, i don't see any battle here." "no," was the reply, "nor you won't see one as long as you hang around washington. if you want to see a battle you must go to the front." the officer thought it unprofitable to continue the conversation, and beat a retreat amid the smiles of the bystanders. this story, i may remark, is quite authentic, which is more than one can say of the report that a stick thrown by a boy at a dog in front of willard's hotel struck twelve brigadier generals during its flight. the presiding genius of the whole was mr. edwin m. stanton, secretary of war. before the actual outbreak of the conflict he had been, i believe, at least a democrat, and, perhaps, to a certain extent, a southern sympathizer so far as the slavery question was concerned. but when it came to blows, he espoused the side of the union, and after being made secretary of war he conducted military operations with a tireless energy, which made him seem the impersonation of the god of war. ordinarily his character seemed almost savage when he was dealing with military matters. he had no mercy on inefficiency or lukewarmness. but his sympathetic attention, when a case called for it, is strikingly shown in the following letter, of which i became possessed by mere accident. at the beginning of the war mr. charles ellet, an eminent engineer, then resident near washington, tendered his services to the government, and equipped a fleet of small river steamers on the mississippi under the war department. in the battle of june 6, 1862, he received a wound from which he died some two weeks later. his widow sold or leased his house on georgetown heights, and i boarded in it shortly afterward. amongst some loose rubbish and old papers lying around in one of the rooms i picked up the letter which follows. war department, washington city, d. c., june 9, 1862. dear madam,--i understand from mr. ellet's dispatch to you that as he will be unfit for duty for some time it will be agreeable to him for you to visit him, traveling slowly so as not to expose your own health. with this view i will afford you every facility within the control of the department, by way of pittsburg and cincinnati to cairo, where he will probably meet you. yours truly, edwin m. stanton, _secretary of war._ the interesting feature of this letter is that it is entirely in the writer's autograph, and bears no mark of having been press copied. i infer that it was written out of office hours, after all the clerks had left the department, perhaps late at night, while the secretary was taking advantage of the stillness of the hour to examine papers and plans. only once did i come into personal contact with mr. stanton. a portrait of ferdinand r. hassler, first superintendent of the coast survey, had been painted about 1840 by captain williams of the corps of engineers, u. s. a., a son-in-law of mr. g. w. p. custis, and therefore a brother-in-law of general lee. the picture at the arlington house was given to mrs. colonel abert, who loaned it to mr. custis. when the civil war began she verbally donated it to my wife, who was mr. hassler's grand-daughter, and was therefore considered the most appropriate depositary of it, asking her to get it if she could. but before she got actual possession of it, the arlington house was occupied by our troops and mr. stanton ordered the picture to be presented to professor agassiz for the national academy of sciences. on hearing of this, i ventured to mention the matter to mr. stanton, with a brief statement of our claims upon the picture. "sir," said he, "that picture was found in the house of a rebel in arms [general robert e. lee], and was justly a prize of war. i therefore made what i considered the most appropriate disposition of it, by presenting it to the national academy of sciences." the expression "house of a rebel in arms" was uttered with such emphasis that i almost felt like one under suspicion of relations with the enemy in pretending to claim the object in question. it was clearly useless to pursue the matter any further at that time. some years later, when the laws were no longer silent, the national academy decided that whoever might be the legal owner of the picture, the academy could have no claim upon it, and therefore suffered it to pass into the possession of the only claimant. among the notable episodes of the civil war was the so-called raid of the confederate general, early, in july, 1864. he had entered maryland and defeated general lew wallace. this left nothing but the well-designed earthworks around washington between his army and our capital. some have thought that, had he immediately made a rapid dash, the city might have fallen into his hands. all in the service of the war and navy departments who were supposed capable of rendering efficient help, were ordered out to take part in the defense of the city, among them the younger professors of the observatory. by order of captain gilliss i became a member of a naval brigade, organized in the most hurried manner by admiral goldsborough, and including in it several officers of high and low rank. the rank and file was formed of the workmen in the navy yard, most of whom were said to have seen military service of one kind or another. the brigade formed at the navy yard about the middle of the afternoon, and was ordered to march out to fort lincoln, a strong earthwork built on a prominent hill, half a mile southwest of the station now known as rives. the reform school of the district of columbia now stands on the site of the fort. the position certainly looked very strong. on the right the fort was flanked by a deep intrenchment running along the brow of the hill, and the whole line would include in the sweep of its fire the region which an army would have to cross in order to enter the city. the naval brigade occupied the trench, while the army force, which seemed very small in numbers, manned the front. i was not assigned to any particular duty, and simply walked round the place in readiness to act whenever called upon. i supposed the first thing to be done was to have the men in the trench go through some sort of drill, in order to assure their directing the most effective fire on the enemy should he appear. the trench was perhaps six feet deep; along its bottom ran a little ledge on which the men had to step in order to deliver their fire, stepping back into the lower depth to load again. along the edge was a sort of rail fence, the bottom rail of which rested on the ground. in order to fire on an enemy coming up the hill, it would be necessary to rest the weapon on this bottom rail. it was quite evident to me that a man not above the usual height, standing on the ledge, would have to stand on tiptoe in order to get the muzzle of his gun properly directed down the slope. if he were at all flurried he would be likely to fire over the head of the enemy. i called attention to this state of things, but did not seem to make any impression on the officers, who replied that the men had seen service and knew what to do. we bivouacked that night, and remained all the next day and the night following awaiting the attack of the enemy, who was supposed to be approaching fort stevens on the seventh street road. at the critical moment, general h. g. wright arrived from fort monroe with his army corps. he and general a. mcd. mccook both took their stations at fort lincoln, which it was supposed would be the point of attack. a quarter or half a mile down the hill was the mansion of the rives family, which a passenger on the baltimore and ohio railway can readily see at the station of that name. a squad of men was detailed to go to this house and destroy it, in case the enemy should appear. the attack was expected at daybreak, but general early, doubtless hearing of the arrival of reinforcements, abandoned any project he might have entertained and had beat a retreat the day before. whether the supposition that he could have taken the city with great celerity has any foundation, i cannot say; i should certainly greatly doubt it, remembering the large loss of life generally suffered during the civil war by troops trying to storm intrenchments or defenses of any sort, even with greatly superior force. i was surprised to find how quickly one could acquire the stolidity of the soldier. during the march from the navy yard to the fort i felt extremely depressed, as one can well imagine, in view of the suddenness with which i had to take leave of my family and the uncertainty of the situation, as well as its extreme gravity. but this depression wore off the next day, and i do not think i ever had a sounder night's sleep in my life than when i lay down on the grass, with only a blanket between myself and the sky, with the expectation of being awakened by the rattle of musketry at daybreak. i remember well how kindly we were treated by the army. the acquaintance of generals wright and mccook, made under such circumstances, was productive of a feeling which has never worn off. it has always been a matter of sorrow to me that the washington of to-day does not show a more lively consciousness of what it owes to these men. one of the entertainments of washington during the early years of the civil war was offered by president lincoln's public receptions. we used to go there simply to see the people and the costumes, the latter being of a variety which i do not think was ever known on such occasions before or since. well-dressed and refined ladies and gentlemen, men in their working clothes, women arrayed in costumes fanciful in cut and brilliant in color, mixed together in a way that suggested a convention of the human race. just where the oddly dressed people came from, or what notion took them at this particular time to don an attire like that of a fancy-dress ball, no one seemed to know. among the never-to-be-forgotten scenes was that following the news of the fall of richmond. if i described it from memory, a question would perhaps arise in the reader's mind as to how much fancy might have added to the picture in the course of nearly forty years. i shall therefore quote a letter written to chauncey wright immediately afterwards, of which i preserved a press copy. observatory, april 7, 1865. dear wright,--yours of the 5th just received. i heartily reciprocate your congratulations on the fall of richmond and the prospective disappearance of the s. c. alias c. s. you ought to have been here monday. the observatory is half a mile to a mile from the thickly settled part of the city. at 11 a. m. we were put upon the qui vive by an unprecedented commotion in the city. from the barracks near us rose a continuous stream of cheers, and in the city was a hubbub such as we had never before heard. we thought it must be petersburg or richmond, but hardly dared to hope which. miss gilliss sent us word that it was really richmond. i went down to the city. all the bedlams in creation broken loose could not have made such a scene. the stores were half closed, the clerks given a holiday, the streets crowded, every other man drunk, and drums were beating and men shouting and flags waving in every direction. i never felt prouder of my country than then, as i compared our present position with our position in the numerous dark days of the contest, and was almost ashamed to think that i had ever said that any act of the government was not the best possible. not many days after this outburst, the city was pervaded by an equally intense and yet deeper feeling of an opposite kind. probably no event in its history caused such a wave of sadness and sympathy as the assassination of president lincoln, especially during the few days while bands of men were scouring the country in search of the assassin. one could not walk the streets without seeing evidence of this at every turn. the slightest bustle, perhaps even the running away of a dog, caused a tremor. i paid one short visit to the military court which was trying the conspirators. the court itself was listening with silence and gravity to the reading of the testimony taken on the day previous. general wallace produced on the spectators an impression a little different from the other members, by exhibiting an artistic propensity, which subsequently took a different direction in "ben hur." the most impressive sight was that of the conspirators, all heavily manacled; even mrs. surratt, who kept her irons partly concealed in the folds of her gown. payne, the would-be assassin of seward, was a powerful-looking man, with a face that showed him ready for anything; but the other two conspirators were such simple-minded, mild-looking youths, that it seemed hardly possible they could have been active agents in such a crime, or capable of any proceeding requiring physical or mental force. the impression which i gained at the time from the evidence and all the circumstances, was that the purpose of the original plot was not the assassination of the president, but his abduction and transportation to richmond or some other point within the confederate lines. while booth himself may have meditated assassination from the beginning, it does not seem likely that he made this purpose known to his fellows until they were ready to act. then payne alone had the courage to attempt the execution of the programme. two facts show that a military court, sitting under such circumstances, must not be expected to reach exactly the verdict that a jury would after the public excitement had died away. among the prisoners was the man whose business it was to assist in arranging the scenery on the stage of the theatre where the assassination occurred. the only evidence against him was that he had not taken advantage of his opportunity to arrest booth as the latter was leaving, and for this he was sentenced to twenty years penal servitude. he was pardoned out before a great while. the other circumstance was the arrest of surratt, who was supposed to stand next to booth in the conspiracy, but who escaped from the country and was not discovered until a year or so later, when he was found to have enlisted in the papal guards at rome. he was brought home and tried twice. on the first trial, notwithstanding the adverse rulings and charge of the judge, only a minority of the jury were convinced of his guilt. on the second trial he was, i think, acquitted. one aftermath of the civil war was the influx of crowds of the newly freed slaves to washington, in search of food and shelter. with a little training they made fair servants if only their pilfering propensities could be restrained. but religious fervor did not ensure obedience to the eighth commandment. "the good lord ain't goin' to be hard on a poor darky just for takin' a chicken now and then," said a wench to a preacher who had asked her how she could reconcile her religion with her indifference as to the ownership of poultry. in the seventies i had an eight-year-old boy as help in my family. he had that beauty of face very common in young negroes who have an admixture of white blood, added to which were eyes of such depth and clearness that, but for his color, he would have made a first-class angel for a mediæval painter. one evening my little daughters had a children's party, and zeke was placed as attendant in charge of the room in which the little company met. here he was for some time left alone. next morning a gold pen was missing from its case in a drawer. suspicion rested on zeke as the only person who could possibly have taken it, but there was no positive proof. i thought so small and innocent-looking a boy could be easily cowed into confessing his guilt; so next morning i said to him very solemnly,-"zeke, come upstairs with me." he obeyed with alacrity, following me up to the room. "zeke, come into this room." he did so. "now, zeke," i said sternly, "look here and see what i do." i opened the drawer, took out the empty case, opened it, and showed it to him. "zeke, look into my eyes!" he neither blinked nor showed the slightest abashment or hesitation as his soft eyes looked steadily into mine with all the innocence of an angel. "zeke, where is the pen out of that case?" "missr newcomb," he said quietly, "i don't know nothin' about it." i repeated the question, looking into his face as sternly as i could. as he repeated the answer with the innocence of childhood, "deed, missr newcomb, i don't know what was in it," i felt almost like a brute in pressing him with such severity. threats were of no avail, and i had to give the matter up as a failure. on coming home in the afternoon, the first news was that the pen had been found by zeke's mother hidden in one corner of her room at home, where the little thief had taken it. she, being an honest woman, and suspecting where it had come from, had brought it back. there was a vigorous movement, having its origin in new england, for the education of the freedmen. this movement was animated by the most philanthropic views. here were several millions of blacks of all ages, suddenly made citizens, or eligible to citizenship, and yet savage so far as any education was concerned. a small army of teachers, many, perhaps most of them, young women, were sent south to organize schools for the blacks. it may be feared that there was little adaptation of the teaching to the circumstances of the case. but one method of instruction widely adopted was, so far as i can learn, quite unique. it was the "loud method" of teaching reading and spelling. the whole school spelled in unison. the passer-by on the street would hear in chorus from the inside of the building, "b-r-e-a-d--bread!" all at the top of the voice of the speakers. schools in which this method was adopted were known as "loud schools." a queer result of this movement once fell under my notice. i called at a friend's house in georgetown. in the course of the conversation, it came out that the sable youngster who opened the door for me filled the double office of scullion to the household and tutor in latin to the little boy of the family. probably the senate of the united states never had a member more conscientious in the discharge of his duties than charles sumner. he went little into society outside the circles of the diplomatic corps, with which his position as chairman of the foreign affairs committee placed him in intimate relations. my acquaintance with him arose from the accident of his living for some time almost opposite me. i was making a study of some historic subject, pertaining to the feeling in south carolina before the civil war, and called at his rooms to see if he would favor me with the loan of a book, which i was sure he possessed. he received me so pleasantly that i was, for some time, an occasional visitor. he kept bachelor quarters on a second floor, lived quite alone, and was accessible to all comers without the slightest ceremony. one day, while i was talking with him, shortly after the surrender of lee, a young man in the garb of a soldier, evidently fresh from the field, was shown into the room by the housemaid, unannounced, as usual. very naturally, he was timid and diffident in approaching so great a man, and the latter showed no disposition to say anything that would reassure him. he ventured to tell the senator that he had come to see if he could recommend him for some public employment. i shall never forget the tone of the reply. "but _i_ do not know _you_." the poor fellow was completely dumfounded, and tried to make some excuses, but the only reply he got was, "i cannot do it; i do not know you at all." the visitor had nothing to do but turn round and leave. at the time i felt some sympathy with the poor fellow. he had probably come, thinking that the great philanthropist was quite ready to become a friend to a union soldier without much inquiry into his personality and antecedents, and now he met with a stinging rebuff. but it must be confessed that subsequent experience has diminished my sympathy for him, and probably it would be better for the country if the innovation were introduced of having every senator of the united states dispose of such callers in the same way. foreign men of letters, with whom sumner's acquaintance was very wide, were always among his most valued guests. a story is told of thackeray's visit to washington, which i distrust only for the reason that my ideas of sumner's make-up do not assign him the special kind of humor which the story brings out. he was, however, quoted as saying, "thackeray is one of the most perfect gentlemen i ever knew. i had a striking illustration of that this morning. we went out for a walk together and, thoughtlessly, i took him through lafayette square. shortly after we entered it, i realized with alarm that we were going directly toward the jackson statue. it was too late to retrace our steps, and i wondered what thackeray would say when he saw the object. but he passed straight by without seeming to see it at all, and did not say one word about it." sumner was the one man in the senate whose seat was scarcely ever vacant during a session. he gave the closest attention to every subject as it arose. one instance of this is quite in the line of the present book. about 1867, an association was organized in washington under the name of the "american union academy of literature, science, and art." its projectors were known to few, or none, but themselves. a number of prominent citizens in various walks of life had been asked to join it, and several consented without knowing much about the association. it soon became evident that the academy was desirous of securing as much publicity as possible through the newspapers and elsewhere. it was reported that the secretary of the treasury had asked its opinion on some instrument or appliance connected with the work of his department. congress was applied to for an act of incorporation, recognizing it as a scientific adviser of the government by providing that it should report on subjects submitted to it by the governmental departments, the intent evidently being that it should supplant the national academy of sciences. the application to congress satisfied the two requirements most essential to favorable consideration. these are that several respectable citizens want something done, and that there is no one to come forward and say that he does not want it done. such being the case, the act passed the house of representatives without opposition, came to the senate, and was referred to the appropriate committee, that on education, i believe. it was favorably reported from the committee and placed on its passage. up to this point no objection seems to have been made to it in any quarter. now, it was challenged by mr. sumner. the ground taken by the massachusetts senator was comprehensive and simple, though possibly somewhat novel. it was, in substance, that an academy of literature, science, and art, national in its character, and incorporated by special act of congress, ought to be composed of men eminent in the branches to which the academy related. he thought a body of men consisting very largely of local lawyers, with scarcely a man of prominence in either of the three branches to which the academy was devoted, was not the one that should receive such sanction from the national legislature. mr. j. w. patterson, of new hampshire, was the principal advocate of the measure. he claimed that the proposed incorporators were not all unscientific men, and cited as a single example the name of o. m. poe, which appeared among them. this man, he said, was a very distinguished meteorologist. this example was rather unfortunate. the fact is, the name in question was that of a well-known officer of engineers in the army, then on duty at washington, who had been invited to join the academy, and had consented out of good nature without, it seems, much if any inquiry. it happened that senator patterson had, some time during the winter, made the acquaintance of a west indian meteorologist named poey, who chanced to be spending some time in washington, and got him mixed up with the officer of engineers. the senator also intimated that the gentleman from massachusetts had been approached on the subject and was acting under the influence of others. this suggestion mr. sumner repelled, stating that no one had spoken to him on the subject, that he knew nothing of it until he saw the bill before them, which seemed to him to be objectionable for the very reasons set forth. on his motion the bill was laid on the table, and thus disposed of for good. the academy held meetings for some time after this failure, but soon disappeared from view, and was never again heard of. in the year 1862, a fine-looking young general from the west became a boarder in the house where i lived, and sat opposite me at table. his name was james a. garfield. i believe he had come to washington as a member of the court in the case of general fitz john porter. he left after a short time and had, i supposed, quite forgotten me. but, after his election to congress, he one evening visited the observatory, stepped into my room, and recalled our former acquaintance. i soon found him to be a man of classical culture, refined tastes, and unsurpassed eloquence,--altogether, one of the most attractive of men. on one occasion he told me one of his experiences in the state legislature of ohio, of which he was a member before the civil war. a bill was before the house enacting certain provisions respecting a depository. he moved, as an amendment, to strike out the word "depository" and insert "depositary." supposing the amendment to be merely one of spelling, there was a general laugh over the house, with a cry of "here comes the schoolmaster!" but he insisted on his point, and sent for a copy of webster's dictionary in order that the two words might be compared. when the definitions were read, the importance of right spelling became evident, and the laughing stopped. it has always seemed to me that a rank injustice was done to garfield on the occasion of the credit mobilier scandal of 1873, which came near costing him his position in public life. the evidence was of so indefinite and flimsy a nature that the credence given to the conclusion from it can only illustrate how little a subject or a document is exposed to searching analysis outside the precincts of a law court. when he was nominated for the presidency this scandal was naturally raked up and much made of it. i was so strongly impressed with the injustice as to write for a new york newspaper, anonymously of course, a careful analysis of the evidence, with a demonstration of its total weakness. whether the article was widely circulated, or whether garfield ever heard of it, i do not know; but it was amusing, a few days after it appeared, to see a paragraph in an opposition paper claiming that its contemporary had gone to the trouble of hiring a lawyer to defend garfield. no man better qualified as a legislator ever occupied a seat in congress. a man cast in the largest mould, and incapable of a petty sentiment, his grasp of public affairs was rarely equaled, and his insight into the effects of legislation was of the deepest. but on what the author of the autocrat calls the arithmetical side,--in the power of judging particular men and not general principles; in deciding who were the good men and who were not, he fell short of the ideal suggested by his legislative career. the brief months during which he administered the highest of offices were stormy enough, perhaps stormier than any president before him had ever experienced, and they would probably have been outdone by the years following, had he lived. but i believe that, had he remained in the senate, his name would have gone into history among those of the greatest of legislators. sixteen years after the death of lincoln public feeling was again moved to its depth by the assassination of garfield. the cry seemed to pass from mouth to mouth through the streets faster than a messenger could carry the news, "the president has been shot." it chanced to reach me just as i was entering my office. i at once summoned my messenger and directed him to go over to the white house, and see if anything unusual had happened, but gave him no intimation of my fears. he promptly returned with the confirmation of the report. the following are extracts from my journal at the time:- "july 2, saturday: at 9.20 this morning president garfield was shot by a miserable fellow named guiteau, as he was passing through the baltimore and potomac r. r. station to leave washington. one ball went through the upper arm, making a flesh wound, the other entered the right side on the back and cannot be found; supposed to have lodged in the liver. in the course of the day president rapidly weakened, and supposed to be dying from hemorrhage." "sunday morning: president still living and rallied during the day. small chance of recovery. at night alarming symptoms of inflammation were exhibited, and at midnight his case seemed almost hopeless." "monday: president slightly better this morning, improving throughout the day." "july 6. this p. m. sought an interview with dr. woodward at the white house, to talk of an apparatus for locating the ball by its action in retarding a rapidly revolving el. magnet. i hardly think the plan more than theoretically practical, owing to the minuteness of the action." "the president still improving, but great dangers are yet to come, and nothing has been found of the ball, which is supposed to have stayed in the liver because, were it anywhere else, symptoms of irritation by its presence would have been shown." "july 9. this is saturday evening. met major powell at the cosmos club, who told me that they would like to have me look at the air-cooling projects at the white house. published statement that the physicians desired some way to cool the air of the president's room had brought a crowd of projects and machines of all kinds. among other things, a mr. dorsey had got from new york an air compressor such as is used in the virginia mines for transferring power, and was erecting machinery enough for a steamship at the east end of the house in order to run it." dr. woodward was a surgeon of the army, who had been on duty at washington since the civil war, in charge of the army medical museum. among his varied works here, that in micro-photography, in which he was a pioneer, gave him a wide reputation. his high standing led to his being selected as one of the president's physicians. to him i wrote a note, offering to be of any use i could in the matter of cooling the air of the president's chamber. he promptly replied with a request to visit the place, and see what was being done and what suggestions i could make. mr. dorsey's engine at the east end was dispensed with after a long discussion, owing to the noise it would make and the amount of work necessary to its final installation and operation. among the problems with which the surgeons had to wrestle was that of locating the ball. the question occurred to me whether it was not possible to do so by the influence produced by the action of a metallic conductor in retarding the motion of a rapidly revolving magnet, but the effect would be so small, and the apparatus to be made so delicate, that i was very doubtful about the matter. if there was any one able to take hold of the project successfully, i knew it would be alexander graham bell, the inventor of the telephone. when i approached him on the subject, he suggested that the idea of locating the ball had also occurred to him, and that he thought the best apparatus for the purpose was a telephonic one which had been recently developed by mr. hughes. as there could be no doubt of the superiority of his project, i dropped mine, and he went forward with his. in a few days an opportunity was given him for actually trying it. the result, though rather doubtful, seemed to be that the ball was located where the surgeons supposed it to be. when the autopsy showed that their judgment had been at fault, mr. bell admitted his error to dr. woodward, adding some suggestion as to its cause. "expectant attention," was woodward's reply. i found in the basement of the house an apparatus which had been brought over by a mr. jennings from baltimore, which was designed to cool the air of dairies or apartments. it consisted of an iron box, two or three feet square, and some five feet long. in this box were suspended cloths, kept cool and damp by the water from melting ice contained in a compartment on top of the box. the air was driven through the box by a blower, and cooled by contact with the wet cloths. but no effect was being produced on the temperature of the room. one conversant with physics will see one fatal defect in this appliance. the cold of the ice, if i may use so unscientific an expression, went pretty much to waste. the air was in contact, not with the ice, as it should have been, but with ice-water, which had already absorbed the latent heat of melting. evidently the air should be passed over the unmelted ice. the question was how much ice would be required to produce the necessary cooling? to settle this, i instituted an experiment. a block of ice was placed in an adjoining room in a current of air with such an arrangement that, as it melted, the water would trickle into a vessel below. after a certain number of minutes the melted water was measured, then a simple computation led to a knowledge of how much heat was absorbed from the air per minute by a square foot of the surface of the ice. from this it was easy to calculate from the known thermal capacity of air, and the quantity of the latter necessary per minute, how many feet of cooling surface must be exposed. i was quite surprised at the result. a case of ice nearly as long as an ordinary room, and large enough for men to walk about in it, must be provided. this was speedily done, supports were erected for the blocks of ice, the case was placed at the end of mr. jennings's box, and everything gotten in readiness for directing the air current through the receptacle, and into the room through tubes which had already been prepared. it happened that mr. jennings's box was on the line along which the air was being conducted, and i was going to get it out of the way. the owner implored that it should be allowed to remain, suggesting that the air might just as well as not continue to pass through it. the surroundings were those in which one may be excused for not being harsh. such an outpouring of sympathy on the part of the public had never been seen in washington since the assassination of lincoln. those in charge were overwhelmed with every sort of contrivance for relieving the sufferings of the illustrious patient. such disinterested efforts in behalf of a public and patriotic object had never been seen. mr. jennings had gone to the trouble and expense of bringing his apparatus all the way from baltimore to washington in order to do what in him lay toward the end for which all were striving. to leave his box in place could not do the slightest harm, and would be a gratification to him. so i let it stand, and the air continued to pass through it on its way to the ice chest. while these arrangements were in progress three officers of engineers of the navy reported under orders at the white house, to do what they could toward the cooling of the air. they were messrs. william l. baillie, richard inch, and w. s. moore. all four of us coöperated in the work in a most friendly way, and when we got through we made our reports to the navy department. a few weeks later these reports were printed in a pamphlet, partly to correct a wrong impression about the jennings cold-box. regular statements had appeared in the local evening paper that the air was being cooled by this useless contrivance. their significance first came out several months later, on the occasion of an exhibition of mechanical or industrial implements at boston. among these was mr. jennings's cold-box, which was exhibited as the instrument that had cooled the air of president garfield's chamber. more light yet was thrown on the case when the question of rewarding those who had taken part in treating the president, or alleviating his sufferings in any way, came before congress. mr. jennings was, i believe, among the claimants. congress found the task of making the proper awards to each individual to be quite beyond its power at the time, so a lump sum was appropriated, to be divided by the treasury department according to its findings in each particular case. before the work of making the awards was completed, i left on the expedition to the cape of good hope to observe the transit of venus, and never learned what had been done with the claims of mr. jennings. it might naturally be supposed that when an official report to the navy department showed that he had no claims whatever except those of a patriotic citizen who had done his best, which was just nothing at all, to promote the common end, the claim would have received little attention. possibly this may have been the case. but i do not know what the outcome of the matter was. shortly after the death of the president, i had a visit from an inventor who had patented a method of cooling the air of a room by ice. he claimed that our work at the executive mansion was an infringement on his patent. i replied that i could not see how any infringement was possible, because we had gone to work in the most natural way, without consulting any previous process whatever, or even knowing of the existence of a patent. surely the operation of passing air over ice to cool it could not be patentable. he invited me to read over the statement of his claims. i found that although this process was not patented in terms, it was practically patented by claiming about every possible way in which ice could be arranged for cooling purposes. placing the ice on supports was one of his claims; this we had undoubtedly done, because otherwise the process could not have been carried out. in a word, the impression i got was that the only sure way of avoiding an infringement would have been to blindfold the men who put the ice in the box, and ask them to throw it in pellmell. every method of using judgment in arranging the blocks of ice he had patented. i had to acknowledge that his claim of infringement might have some foundation, and inquired what he proposed to do in the case. he replied that he did not wish to do more than have his priority recognized in the matter. i replied that i had no objection to his doing this in any way he could, and he took his leave. nothing more, so far as i am aware, was done in his case. but i was much impressed by this as by other examples i have had of the same kind, of the loose way in which our patent office sometimes grants patents. i do not think the history of any modern municipality can show an episode more extraordinary or, taken in connection with its results, more instructive than what is known as the "shepherd régime" in washington. what is especially interesting about it is the opposite views that can be taken of the same facts. as to the latter there is no dispute. yet, from one point of view, shepherd made one of the most disastrous failures on record in attempting to carry out great works, while, from another point of view, he is the author of the beautiful washington of to-day, and entitled to a public statue in recognition of his services. as i was a resident of the city and lived in my own house, i was greatly interested in the proposed improvements, especially of the particular street on which i lived. i was also an eye-witness to so much of the whole history as the public was cognizant of. the essential facts of the case, from the two, opposing points of view, are exceedingly simple. one fact is the discreditable condition of the streets of washington during and after the civil war. the care of these was left entirely to the local municipality. congress, so far as i know, gave no aid except by paying its share of street improvements in front of the public buildings. it was quite out of the power of the residents, who had but few men of wealth among them, to make the city what it ought to be. congress showed no disposition to come to the help of the citizens in this task. in 1871, however, some public-spirited citizens took the matter in hand and succeeded in having a new government established, which was modeled after that of the territories of the united states. there was a governor, a legislature, and a board of public works. the latter was charged with the improvements of the streets, and the governor was _ex officio_ its president. the first governor was henry d. cooke, the banker, and mr. shepherd was vice-president of the board of public works and its leading member. mr. cooke resigned after a short term, and mr. shepherd was promoted to his place. he was a plumber and gas-fitter by trade, and managed the leading business in his line in washington. through the two or three years of his administration the city directory still contained the entry-shepherd, alex. r. & co., plumbers and gas-fitters, 910 pa. ave. n. w. in recent years he had added to his plumbing business that of erecting houses for sale. he had had no experience in the conduct of public business, and, of course, was neither an engineer nor a financier. but such was the energy of his character and his personal influence, that he soon became practically the whole government, which he ran in his own way, as if it were simply his own business enlarged. of the conditions which the law imposes on contracts, of the numerous and complicated problems of engineering involved in the drainage and street systems of a great city, of the precautions to be taken in preparing plans for so immense a work, and of the legal restraints under which it should be conducted, he had no special knowledge. but he had in the highest degree a quality which will bear different designations according to the point of view. his opponents would call it unparalleled recklessness; his supporters, boldness and enterprise. such were the preliminaries. three years later the results of his efforts were made known by an investigating committee of congress, with senator allison, a political friend, at its head. it was found that with authority to expend $6,000,000 in the improvement of the streets, there was an actual or supposed expenditure of more than $18,000,000, and a crowd of additional claims which no man could estimate, based on the work of more than one thousand principal contractors and an unknown number of purchasers and sub-contractors. chaos reigned supreme. some streets were still torn up and impassable; others completely paved, but done so badly that the pavements were beginning to rot almost before being pressed by a carriage. a debt had been incurred which it was impossible for the local municipality to carry and which was still piling up. for all this congress was responsible, and manfully shouldered its responsibility. mr. shepherd was legislated out of office as an act of extreme necessity, by the organization of a government at the head of which were three commissioners. the feeling on the subject may be inferred from the result when president grant, who had given shepherd his powerful support all through, nominated him as one of the three commissioners. the senate rejected the nomination, with only some half dozen favorable votes. the three commissioners took up the work and carried it on in a conservative way. congress came to the help of the municipality by bearing one half the taxation of the district, on the very sound basis that, as it owned about one half of the property, it should pay one half the taxes. the spirit of the time is illustrated by two little episodes. the reservation on which the public library founded by mr. carnegie is now built, was then occupied by the northern liberties market, one of the three principal markets of the city. being a public reservation, it had no right to remain there except during the pleasure of the authorities. due notice was given to the marketmen to remove the structures. the owners were dilatory in doing so, and probably could not see why they should be removed when the ground was not wanted for any other purpose, and before they had time to find a new location. it was understood that, if an attempt was made to remove the buildings, the marketmen would apply to the courts for an injunction. to prevent this, an arrangement was made by which the destruction of the buildings was to commence at dinner-time. at the same time, according to current report, it was specially arranged that all the judges to whom an application could be made should be invited out to dinner. however this may have been, a large body of men appeared upon the scene in the course of the evening and spent the night in destroying the buildings. with such energy was the work carried on that one marketman was killed and another either wounded or seriously injured in trying to save their wares from destruction. the indignation against shepherd was such that his life was threatened, and it was even said that a body-guard of soldiers had to be supplied by the war department for his protection. the other event was as comical as this was tragic. it occurred while the investigating committee of congress was at its work. the principal actors in the case were mr. harrington, secretary of the local government and one of mr. shepherd's assistants, the chief of police, and a burglar. harrington produced an anonymous letter, warning him that an attempt would be made in the course of a certain night to purloin from the safe in which they were kept, certain government papers, which the prosecutors of the case against shepherd were anxious to get hold of. he showed this letter to the chief of police, who was disposed to make light of the matter. but on harrington's urgent insistence the two men kept watch about the premises on the night in question. they were in the room adjoining that in which the records were kept, and through which the robber would have to pass. in due time the latter appeared, passed through the room and proceeded to break into the safe. the chief wanted to arrest him immediately, but harrington asked him to wait, in order that they might see what the man was after, and especially what he did with the books. so they left and took their stations outside the door. the burglar left the building with the books in a satchel, and, stepping outside, was confronted by the two men. i believe every burglar of whom history or fiction has kept any record, whether before or after this eventful night, when he broke open a safe and, emerging with his booty, found himself confronted by a policeman, took to his heels. not so this burglar. he walked up to the two men, and with the utmost unconcern asked if they could tell him where mr. columbus alexander lived. mr. alexander, it should be said, was the head man in the prosecution. the desired information being conveyed to the burglar, he went on his way to mr. alexander's house, followed by the two agents of the law. arriving there, he rang the bell. in the ordinary course of events, mr. alexander or some member of his family would have come to the door and been informed that the caller had a bundle for him. a man just awakened from a sound sleep and coming downstairs rubbing his eyes, would not be likely to ask any questions of such a messenger, but would accept the bundle and lock the door again. then what a mess the prosecution would have been in! its principal promoter detected in collusion with a burglar in order to get possession of the documents necessary to carry on his case! it happened, however, that mr. alexander and the members of his household all slept the sleep of the just and did not hear the bell. the patience of the policeman was exhausted and the burglar was arrested and lodged in jail, where he was kept for several months. public curiosity to hear the burglar's story was brought to a high pitch, but never gratified. before the case came to trial the prisoner was released on straw bail and never again found. i do not think the bottom facts, especially those connected with the anonymous letter, were ever brought to light. so every one was left to form his own theory of what has since been known as the "safe burglary conspiracy." what seems at present the fashionable way of looking at the facts is this: shepherd was the man who planned the beautiful washington of to-day, and who carried out his project with unexampled energy until he was stopped through the clamor of citizens who did not want to see things go ahead so fast. other people took the work up, but they only carried out shepherd's ideas. the latter, therefore, should have all the credit due to the founder of the new washington. the story has always seemed to me most interesting as an example of the way in which public judgment of men and things is likely to be influenced. public sentiment during the thirty years which have since elapsed has undergone such a revolution in favor of shepherd that a very likely outcome will be a monument to commemorate his work. but it is worth while to notice the mental processes by which the public now reaches this conclusion. it is the familiar and ordinarily correct method of putting this and that together. _this_ is one of the most beautiful cities in the united states, of which americans generally are proud when they pay it a visit. _that_ is the recollection of the man who commenced the work of transforming an unsightly, straggling, primitive town into the present washington, and was condemned for what he did. these two considerations form the basis of the conclusion, all intermediate details dropping out of sight and memory. the reckless maladministration of the epoch, making it absolutely necessary to introduce a new system, has no place in the picture. there is also a moral to the story, which is more instructive than pleasant. the actors in the case no doubt believed that if they set about their work in a conservative and law-abiding way, spending only as much money as could be raised, congress would never come to their help. so they determined to force the game, by creating a situation which would speedily lead to the correct solution of the problem. i do not think any observant person will contest the proposition that had shepherd gone about his work and carried it to a successful conclusion in a peaceable and law-abiding way,--had he done nothing to excite public attention except wisely and successfully to administer a great public work,--his name would now have been as little remembered in connection with what he did as we remember those of ketchem, phelps, and the other men who repaired the wreck he left and made the city what it is to-day. in my mind one question dominates all others growing out of the case: what will be the moral effect on our children of holding up for their imitation such methods as i have described? xiii miscellanea if the "great star-catalogue case" is not surrounded with such mystery as would entitle it to a place among _causes célèbres_, it may well be so classed on account of the novelty of the questions at issue. it affords an instructive example of the possibility of cases in which strict justice cannot be done through the established forms of legal procedure. it is also of scientific interest because, although the question was a novel one to come before a court, it belongs to a class which every leader in scientific investigation must constantly encounter in meting out due credit to his assistants. the plaintiff, christian h. f. peters, was a dane by birth, and graduated at the university of berlin in 1836. during the earlier years of his manhood he was engaged in the trigonometrical survey of the kingdom of naples, where, for a time, he had charge of an observatory or some other astronomical station. it is said that, like many other able european youth of the period, he was implicated in the revolution of 1848, and had to flee the kingdom in consequence. five years later, he came to the united states. here his first patron was dr. b. a. gould, who procured for him first a position on the coast survey, and then one as his assistant at the dudley observatory in albany. he was soon afterward appointed professor of astronomy and director of the litchfield observatory at hamilton college, where he spent the remaining thirty years of his life. he was a man of great learning, not only in subjects pertaining to astronomy, but in ancient and modern languages. the means at his disposal were naturally of the slenderest kind; but he was the discoverer of some forty asteroids, and devoted himself to various astronomical works and researches with great ability. of his personality it may be said that it was extremely agreeable so long as no important differences arose. what it would be in such a case can be judged by what follows. those traits of character which in men like him may be smoothed down to a greater or less extent by marital discipline were, in the absence of any such agency, maintained in all their strength to his latest years. the defendant, charles a. borst, was a graduate of the college and had been a favorite pupil of peters. he was a man of extraordinary energy and working capacity, ready to take hold in a business-like way of any problem presented to him, but not an adept at making problems for himself. his power of assimilating learning was unusually developed; and this, combined with orderly business habits, made him a most effective and valuable assistant. the terms of his employment were of the first importance in the case. mr. litchfield of new york was the patron of the observatory; he had given the trustees of hamilton college a capital for its support, which sufficed to pay the small salary of the director and some current expenses, and he also, when the latter needed an assistant, made provision for his employment. it appears that, in the case of borst, peters frequently paid his salary for considerable periods at a time, which sums were afterward reimbursed to him by mr. litchfield. i shall endeavor to state the most essential facts involved as they appear from a combination of the sometimes widely different claims of the two parties, with the hope of showing fairly what they were, but without expecting to satisfy a partisan of either side. where an important difference of statement is irreconcilable, i shall point it out. in his observations of asteroids peters was continually obliged to search through the pages of astronomical literature to find whether the stars he was using in observation had ever been catalogued. he long thought that it would be a good piece of work to search all the astronomical journals and miscellaneous collections of observations with a view of making a complete catalogue of the positions of the thousands of stars which they contained, and publishing it in a single volume for the use of astronomers situated as he was. the work of doing this was little more than one of routine search and calculation, which any well-trained youth could take up; but it was naturally quite without the power of peters to carry it through with his own hand. he had employed at least one former assistant on the work, professor john g. porter, but very little progress was made. now, however, he had a man with the persistence and working capacity necessary to carry out the plan. there was an irreconcilable difference between the two parties as to the terms on which borst went to work. according to the latter, peters suggested to him the credit which a young man would gain as one of the motives for taking up the job. but plaintiff denied that he had done anything more than order him to do it. he did not, however, make it clear why an assistant at the litchfield observatory should be officially ordered to do a piece of work for the use of astronomy generally, and having no special connection with the litchfield observatory. however this may be, borst went vigorously to work, repeating all the calculations which had been made by peters and former assistants, with a view of detecting errors, and took the work home with him in order that his sisters might make a great mass of supplementary calculations which, though not involved in the original plan, would be very conducive to the usefulness of the result. one or two of these bright young ladies worked for about a year at the job. how far peters was privy to what they did was not clear; according to his claim he did not authorize their employment to do anything but copy the catalogue. by the joint efforts of the assistant and his two sisters, working mostly or entirely at their own home, the work was brought substantially to a conclusion about the beginning of 1888. borst then reported the completion to his chief and submitted a proposed title-page, which represented that the work was performed by charles a. borst under the direction of christian h. f. peters, professor of astronomy, etc. according to borst's account, peters tore up the paper, opened the stove door, put the fragments into the fire, and then turned on the assistant with the simple order, "bring me the catalogue!" this was refused, and a suit in replevin was immediately instituted by peters. the ablest counsel were engaged on both sides. that of the plaintiff was mr. elihu root, of new york, afterward secretary of war, one of the leading members of the new york bar, and well known as an active member of the reform branch of the republican party of that city. for the defendant was the law firm of an ex-senator of the united states, the messrs. kernan of utica. i think the taking of evidence and the hearing of arguments occupied more than a week. one claim of the defendant would, if accepted, have brought the suit to a speedy end. peters was an employee of the corporation of hamilton college, and by the terms of his appointment all his work at the litchfield observatory belonged to that institution. borst was summoned into the case as an official employee of the litchfield observatory. therefore the corporation of the college was the only authority which had power to bring the suit. but this point was disposed of by a decision of the judge that it was not reasonable, in view of the low salary received by the plaintiff, to deprive him of the right to the creations of his own talent. he did not, however, apply this principle of legal interpretation to the case of the defendant, and not only found for the plaintiff, but awarded damages based on the supposed value of the work, including, if i understand the case aright, the value of the work done by the young ladies. it would seem, however, that in officially perfecting the details of his decision he left it a little indefinite as to what papers the plaintiff was entitled to, it being very difficult to describe in detail papers many of which he had never seen. altogether it may be feared that the decision treated the catalogue much as the infant was treated by the decision of solomon. however this might he, the decision completely denied any right of the defendant in the work. this feature of it i thought very unjust, and published in a utica paper a review of the case in terms not quite so judicial as i ought to have chosen. i should have thought such a criticism quite a breach of propriety, and therefore would never have ventured upon it but for an eminent example then fresh in my mind. shortly after the supreme court of the united states uttered its celebrated decision upholding the constitutionality of the legal tender act, i happened to be conversing at an afternoon reception with one of the judges, gray, who had sustained the decision. mr. george bancroft, the historian, stepped up, and quite surprised me by expressing to the judge in quite vigorous language his strong dissent from the decision. he soon afterward published a pamphlet reviewing it adversely. i supposed that what mr. bancroft might do with a decision of the supreme court of the united states, a humbler individual might be allowed to do with the decision of a local new york judge. the defense appealed the case to a higher court of three judges, where the finding of the lower court was sustained by a majority of two to one. it was then carried to the court of appeals, the highest in the state. here the decision was set aside on what seemed to me the common sense ground that the court had ignored the rights of the defendant in the case, who certainly had some, and it must therefore be remanded for a new trial. meantime peters had died; and it is painful to think that his death may have been accelerated by the annoyances growing out of the suit. one morning, in the summer of 1890, he was found dead on the steps of his little dwelling, having apparently fallen in a fit of apoplexy or heart failure as he was on his way to the observatory the night before. his heirs had no possible object in pushing the suit; probably his entire little fortune was absorbed in the attendant expenses. when the difference with borst was first heard of it was, i think, proposed to peters by several of his friends, including myself, that the matter should be submitted to an arbitration of astronomers. but he would listen to nothing of the sort. he was determined to enforce his legal rights by legal measures. a court of law was, in such a case, at an enormous disadvantage, as compared with an astronomical board of arbitration. to the latter all the circumstances would have been familiar and simple, while the voluminous evidence, elucidated as it was by the arguments of counsel on the two sides, failed to completely enlighten the court on the points at issue. one circumstance will illustrate this. some allusion was made during the trial to peters's work while he was abroad, in investigating the various manuscripts of the almagest of ptolemy and preparing a commentary and revised edition of ptolemy's catalogue of stars. this would have been an extremely important and original work, most valuable in the history of ancient astronomy. but the judge got it mixed up in his mind with the work before the court, and actually supposed that peters spent his time in europe in searching ancient manuscripts to get material for the catalogue in question. he also attributed great importance to the conception of the catalogue, forgetting that, to use the simile of a writer in the "new york evening post," such a conception was of no more value than the conception of a railroad from one town to another by a man who had no capital to build it. no original investigation was required on one side or the other. it was simply a huge piece of work done by a young man with help from his sisters, suggested by peters, and now and then revised by him in its details. it seemed to me that the solution offered by borst was eminently proper, and i was willing to say so, probably at the expense of peters's friendship, on which i set a high value. i have always regarded the work on ptolemy's catalogue of stars, to which allusion has just been made, as the most important peters ever undertook. it comprised a critical examination and comparison of all the manuscripts of the almagest in the libraries of europe, or elsewhere, whether in arabic or other languages, with a view of learning what light might be thrown on the doubtful questions growing out of ptolemy's work. at the litchfield observatory i had an opportunity of examining the work, especially the extended commentaries on special points, and was so impressed by the learning shown in the research as to express a desire for its speedy completion and publication. in fact, peters had already made one or more communications to the national academy of sciences on the subject, which were supposed to be equivalent to presenting the work to the academy for publication. but before the academy put in any claim for the manuscript, mr. e. b. knobel of london, a well-known member of the royal astronomical society, wrote to peters's executors, stating that he was a collaborator with peters in preparing the work, and as such had a claim to it, and wished to complete it. he therefore asked that the papers should be sent to him. this was done, but during the twelve years which have since elapsed, nothing more has been heard of the work. no one, so far as i know, ever heard of peters's making any allusion to mr. knobel or any other collaborator. he seems to have always spoken of the work as exclusively his own. among the psychological phenomena i have witnessed, none has appeared to me more curious than a susceptibility of certain minds to become imbued with a violent antipathy to the theory of gravitation. the anti-gravitation crank, as he is commonly called, is a regular part of the astronomer's experience. he is, however, only one of a large and varied class who occupy themselves with what an architect might consider the drawing up of plans and specifications for a universe. this is, no doubt, quite a harmless occupation; but the queer part of it is the seeming belief of the architects that the actual universe has been built on their plans, and runs according to the laws which they prescribe for it. ether, atoms, and nebulæ are the raw material of their trade. men of otherwise sound intellect, even college graduates and lawyers, sometimes engage in this business. i have often wondered whether any of these men proved that, in all the common schools of new york, the power which conjugates the verbs comes, through some invisible conduit in the earth, from the falls of niagara. this would be quite like many of the theories propounded. babbage's "budget of paradoxes" is a goodly volume descriptive of efforts of this sort. it was supplemented a year or two ago by a most excellent and readable article on eccentric literature, by mr. john fiske, which appeared in the "atlantic monthly." here the author discussed the subject so well that i do not feel like saying much about it, beyond giving a little of my own experience. naturally the smithsonian institution was, and i presume still is, the great authority to which these men send their productions. it was generally a rule of professor henry always to notice these communications and try to convince the correspondents of their fallacies. many of the papers were referred to me; but a little experience showed that it was absolutely useless to explain anything to these "paradoxers." generally their first communication was exceedingly modest in style, being evidently designed to lead on the unwary person to whom it was addressed. moved to sympathy with so well-meaning but erring an inquirer, i would point out wherein his reasoning was deficient or his facts at fault. back would come a thunderbolt demonstrating my incapacity to deal with the subject in terms so strong that i could not have another word to say. the american association for the advancement of science was another attraction for such men. about thirty years ago there appeared at one of its meetings a man from new jersey who was as much incensed against the theory of gravitation as if it had been the source of all human woe. he got admission to the meetings, as almost any one can, but the paper he proposed to read was refused by the committee. he watched his chance, however, and when discussion on some paper was invited, he got up and began with the words, "it seems to me that the astronomers of the present day have gravitation on the brain." this was the beginning of an impassioned oration which went on in an unbroken torrent until he was put down by a call for the next paper. but he got his chance at last. a meeting of section q was called; what this section was the older members will recall and the reader may be left to guess. a programme of papers had been prepared, and on it appeared mr. joseph treat, on gravitation. mr. treat got up with great alacrity, and, amid the astonishment and laughter of all proceeded to read his paper with the utmost seriousness. i remember a visit from one of these men with great satisfaction, because, apparently, he was an exception to the rule in being amenable to reason. i was sitting in my office one morning when a modest-looking gentleman opened the door and looked in. "i would like to see professor newcomb." "well, here he is." "you professor newcomb?" "yes." "professor, i have called to tell you that i don't believe in sir isaac newton's theory of gravitation!" "don't believe in gravitation! suppose you jump out of that window and see whether there is any gravitation or not." "but i don't mean that. i mean"-"but that is all there is in the theory of gravitation; if you jump out of the window you'll fall to the ground." "i don't mean that. what i mean is i don't believe in the newtonian theory that gravitation goes up to the moon. it does n't extend above the air." "have you ever been up there to see?" there was an embarrassing pause, during which the visitor began to look a little sheepish. "n-no-o," he at length replied. "well, i have n't been there either, and until one of us can get up there to try the experiment, i don't believe we shall ever agree on the subject." he took his leave without another word. the idea that the facts of nature are to be brought out by observation is one which is singularly foreign not only to people of this class, but even to many sensible men. when the great comet of 1882 was discovered in the neighborhood of the sun, the fact was telegraphed that it might be seen with the naked eye, even in the sun's neighborhood. a news reporter came to my office with this statement, and wanted to know if it was really true that a comet could be seen with the naked eye right alongside the sun. "i don't know," i replied; "suppose you go out and look for yourself; that is the best way to settle the question." the idea seemed to him to be equally amusing and strange, and on the basis of that and a few other insipid remarks, he got up an interview for the "national republican" of about a column in length. i think there still exists somewhere in the northwest a communistic society presided over by a genius whose official name is koresh, and of which the religious creed has quite a scientific turn. its fundamental doctrine is that the surface of the earth on which we live is the inside of a hollow sphere, and therefore concave, instead of convex, as generally supposed. the oddest feature of the doctrine is that koresh professes to have proved it by a method which, so far as the geometry of it goes, is more rigorous than any other that science has ever applied. the usual argument by which we prove to our children the earth's rotundity is not purely geometric. when, standing on the seashore, we see the sails of a ship on the sea horizon, her hull being hidden because it is below, the inference that this is due to the convexity of the surface is based on the idea that light moves in a straight line. if a ray of light is curved toward the surface, we should have the same appearance, although the earth might be perfectly flat. so the koresh people professed to have determined the figure of the earth's surface by the purely geometric method of taking long, broad planks, perfectly squared at the two ends, and using them as a geodicist uses his base apparatus. they were mounted on wooden supports and placed end to end, so as to join perfectly. then, geometrically, the two would be in a straight line. then the first plank was picked up, carried forward, and its end so placed against that of the second as to fit perfectly; thus the continuation of a straight line was assured. so the operation was repeated by continually alternating the planks. recognizing the fact that the ends might not be perfectly square, the planks were turned upside down in alternate settings, so that any defect of this sort would be neutralized. the result was that, after they had measured along a mile or two, the plank was found to be gradually approaching the sea sand until it touched the ground. this quasi-geometric proof was to the mind of koresh positive. a horizontal straight line continued does not leave the earth's surface, but gradually approaches it. it does not seem that the measurers were psychologists enough to guard against the effect of preconceived notions in the process of applying their method. it is rather odd that pure geometry has its full share of paradoxers. runkle's "mathematical monthly" received a very fine octavo volume, the printing of which must have been expensive, by mr. james smith, a respectable merchant of liverpool. this gentleman maintained that the circumference of a circle was exactly 3 1/5 times its diameter. he had pestered the british association with his theory, and come into collision with an eminent mathematician whose name he did not give, but who was very likely professor demorgan. the latter undertook the desperate task of explaining to mr. smith his error, but the other evaded him at every point, much as a supple lad might avoid the blows of a prize-fighter. as in many cases of this kind, the reasoning was enveloped in a mass of verbiage which it was very difficult to strip off so as to see the real framework of the logic. when this was done, the syllogism would be found to take this very simple form:-the ratio of the circumference to the diameter is the same in all circles. now, take a diameter of 1 and draw round it a circumference of 3 1/5. in that circle the ratio is 3 1/5; therefore, by the major premise, that is the ratio for all circles. the three famous problems of antiquity, the duplication of the cube, the quadrature of the circle, and the trisection of the angle, have all been proved by modern mathematics to be insoluble by the rule and compass, which are the instruments assumed in the postulates of euclid. yet the problem of the trisection is frequently attacked by men of some mathematical education. i think it was about 1870 that i received from professor henry a communication coming from some institution of learning in louisiana or texas. the writer was sure he had solved the problem, and asked that it might receive the prize supposed to be awarded by governments for the solution. the construction was very complicated, and i went over the whole demonstration without being able at first to detect any error. so it was necessary to examine it yet more completely and take it up point by point. at length i found the fallacy to be that three lines which, as drawn, intersected in what was to the eye the same point on the paper, were assumed to intersect mathematically in one and the same point. except for the complexity of the work, the supposed construction would have been worthy of preservation. some years later i received, from a teacher, i think, a supposed construction, with the statement that he had gone over it very carefully and could find no error. he therefore requested me to examine it and see whether there was anything wrong. i told him in reply that his work showed that he was quite capable of appreciating a geometric demonstration; that there was surely something wrong in it, because the problem was known to be insoluble, and i would like him to try again to see if he could not find his error. as i never again heard from him, i suppose he succeeded. one of the most curious of these cases was that of a student, i am not sure but a graduate, of the university of virginia, who claimed that geometers were in error in assuming that a line had no thickness. he published a school geometry based on his views, which received the endorsement of a well-known new york school official and, on the basis of this, was actually endorsed, or came very near being endorsed, as a text-book in the public schools of new york. from my correspondence, i judge that every civilized country has its share of these paradoxers. i am almost constantly in receipt of letters not only from america, but from europe and asia, setting forth their views. the following are a few of these productions which arrived in the course of a single season. baltimore, sept. 29, 1897. 104 collington ave. prof. simon newcomb: _dear sir_,--though a stranger to you, sir, i take the liberty to enlist your interest in a cause,--so grand, so beautiful, as to eclipse anything ever presented to the highest tribunal of human intellect and intuition. trusting you to be of liberal mind, sir, i have mailed you specimen copy of the "banner of light," which will prove somewhat explanatory of my previous remarks. being a student of nature and her wonderful laws, as they operate in that subtle realm of human life,--the soul, for some years, i feel well prepared to answer inquiries pertaining to this almost unknown field of scientific research, and would do so with much pleasure, as i am desirous to contribute my mite to the enlightenment of mankind upon this most important of all subjects. yours very truly, ---------- p. s.--would be pleased to hear from you, sir. mexico, 16 oct. 1897. dear sir,--i beg to inform you that i have forwarded by to days mail to your adress a copy of my 20th century planetary spectacle with a clipping of a german newspaper here. thirty hours for 3000 years is to day better accepted than it was 6 years ago when i wrote it, although it called even then for some newspaper comment, especially after president cleveland's election, whose likeness has been recognized on the back cover, so has been my comet, which was duly anounced by an italian astronomer 48 hours before said election. a hint of jupiters fifth satelite and mars satelites is also to be found in my planetary spectacle but the most striking feature of such a profetic play is undoubtedly the allegory of the paris fire my entire mercury scene and next to it is the mars scene with the wholesale retreat of the greecs that is just now puzzling some advanced minds. of cours the musical satelites represent at the same time the european concert with the disgusted halfuroons face in one corner and egypt next to it and there can be no doubt that the world is now about getting ready to applaud such a grand realistic play on the stage after even the school children of chicago adopted a great part of my moral scuol-club (act ii) as i see from the times herald oct. 3d. and they did certainly better than the mars fools did in n. y. 4 years ago with that dire play, a trip to mars. the only question now is to find an enterprising scientist to not only recomend my play but put some 1500$ up for to stage it at once perhaps you would be able to do so. yours truly g. a. kastelic, hotel buenavista. in the following dr. diaforus of the _malade imaginaire_ seems to have a formidable rival. chicago, oct. 31, 1897. mr. newcombe: _dear sir_,--i forwarded you photographs of several designs which demonstrate by illustrations in physics, metaphysics, phrenology, mechanics, theology, law magnetism astronomy etc--the only true form and principles of universal government, and the greatest life sustaining forces in this universe, i would like to explain to you and to some of the expert government detectives every thing in connection with those illustrations since 1881; i have traveled over this continent; for many years i have been persecuted. my object in sending you those illustrations is to see if you could influence some journalist in this city, or in washington to illustrate and write up the interpretation of those designs, and present them to the public through the press. you know that very few men can grasp or comprehend in what relation a plumb line stands to the sciences, or to the nations of this earth, at the present time, by giving the correct interpretation of christian, hebrew, & mohammedian prophesy, this work presents a system of international law which is destined to create harmony peace and prosperity. sincerely yours ---------- 1035 monadnock bld chicago ill c/o l. l. smith. p. s. the very law that moulds a tear; and bids it trickel from its source; that law preserves this earth a sphere, and guides the planets in their course. ord neb nove 18, 1897. professor simon newcomb washington d c _dear sir_,--as your labors have enabled me to protect my honor and prove the copernican newton keplar and gallileo theories false i solicit transportation to your department so that i can come and explain the whole of nature and so enable you to obtain the true value of the moon from both latitudes at the same instant. my method of working does not accord with yours hence will require more time to comprehend i have asked professor james e keeler to examine the work and forward his report with this application for transportation yours truly ----------one day in july, 1895, i was perplexed by the receipt of a cable dispatch from paris in the following terms:- will you act? consult gould. furber. the dispatch was accompanied by the statement that an immediate answer was requested and prepaid. dr. gould being in cambridge, and i in washington, it was not possible to consult him immediately as to what was meant. after consultation with an official of the coast survey, i reached the conclusion that the request had something to do with the international metric commission, of which dr. gould was a member, and that i was desired to act on some committee. as there could be no doubt of my willingness to do this, i returned an affirmative answer, and wrote to dr. gould to know exactly what was required. great was my surprise to receive an answer stating that he knew nothing of the subject, and could not imagine what was meant. the mystery was dispelled a few days later by a visit from dr. e. r. l. gould, the well-known professor of economics, who soon after extended his activities into the more practical line of the presidency of the suburban homes and improvement company of new york. he had just arrived from paris, where a movement was on foot to induce the french government to make such modifications in the regulations governing the instruction and the degrees at the french universities as would make them more attractive to american students, who had hitherto frequented the german universities to the almost entire exclusion of those of france. it was desired by the movers in the affair to organize an american committee to act with one already formed at paris; and it was desired that i should undertake this work. i at first demurred on two grounds. i could not see how, with propriety, americans could appear as petitioners to the french government to modify its educational system for their benefit. moreover, i did not want to take any position which would involve me in an effort to draw american students from the german universities. he replied that neither objection could be urged in the case. the american committee would act only as an adviser to the french committee, and its sole purpose was to make known to the latter what arrangements as regarded studies, examinations, and degrees would be best adapted to meet the views and satisfy the needs of american students. there was, moreover, no desire to draw american students from the german universities; it was only desired to give them greater facilities in paris. the case was fortified by a letter from m. michel bréal, member of the institute of france, and head of the franco-american committee, as it was called in paris, expressing a very flattering desire that i should act. i soon gave my consent, and wrote to the presidents of eight or ten of our leading universities and several washington officials interested in education, to secure their adhesion. with a single exception, the responses were unanimous in the affirmative, and i think the exception was due to a misapprehension of the objects of the movement. the views of all the adhering americans were then requested, and a formal meeting was held, at which they were put into shape. it is quite foreign to my present object to go into details, as everything of interest in connection with the matter will be found in educational journals. one point may, however, be mentioned. the french committee was assured that whatever system of instruction and of degrees was offered, it must be one in which no distinction was made between french and foreigners. american students would not strive for a degree which was especially arranged for them alone. i soon found that the movement was a much more complex one than it appeared at first sight, and that all the parties interested in paris did not belong to one and the same committee. not long after we had put our suggestions into shape, i was gratified by a visit from dom de la tremblay, prior of the benedictine convent of santa maria, in paris, a most philanthropic and attractive gentleman, who desired to promote the object by establishing a home for the american students when they should come. knowing the temptations to which visiting youth would be exposed, he was desirous of founding an establishment where they could live in the best and most attractive surroundings. he confidently hoped to receive the active support of men of wealth in this country in carrying out his object. it was a somewhat difficult and delicate matter to explain to the philanthropic gentleman that american students were not likely to collect in a home specially provided for them, but would prefer to find their own home in their own way. i tried to do it with as little throwing of cold water as was possible, but, i fear, succeeded only gradually. but after two or three visits to new york and washington, it became evident to him that the funds necessary for his plan could not be raised. the inception of the affair was still not clear to me. i learned it in paris the year following. then i found that the movement was started by mr. furber, the sender of the telegram, a citizen of chicago, who had scarcely attained the prime of life, but was gifted with that indomitable spirit of enterprise which characterizes the metropolis of the west. what he saw of the educational institutions of paris imbued him with a high sense of their value, and he was desirous that his fellow-countrymen should share in the advantages which they offered. to induce them to do this, it was only necessary that some changes should be made in the degrees and in the examinations, the latter being too numerous and the degrees bearing no resemblance to those of germany and the united states. he therefore addressed a memorial to the minister of public instruction, who was much impressed by the view of the case presented to him, and actively favored the formation of a franco-american committee to carry out the object. everything was gotten ready for action, and it only remained that the prime mover should submit evidence that educators in america desired the proposed change, and make known what was wanted. why i should have been selected to do this i do not know, but suppose it may have been because i had just been elected a foreign associate of the institute, and was free from trammels which might have hindered the action of men who held official positions in the government or at the heads of universities. the final outcome of the affair was the establishment in the universities of france of the degree of doctor of the university, which might be given either in letters or in science, and which was expected to correspond as nearly as possible to the degree of doctor of philosophy in germany and america. one feature of the case was brought out which may be worthy of attention from educators. in a general way it may be said that our bachelor's degree does not correspond to any well-defined stage of education, implying, as it does, something more than that foundation of a general liberal education which the degree implies in europe, and not quite so much as the doctor's degree. i found it very difficult, if not impossible, to make our french friends understand that our american bachelor's degree was something materially higher than the baccalaureate of the french lycée, which is conferred at the end of a course midway between our high school and our college. from education at the sorbonne i pass to the other extreme. during a stay in harper's ferry in the autumn of 1887, i had an object lesson in the state of primary education in the mountain regions of the south. accompanied by a lady friend, who, like myself, was fond of climbing the hills, i walked over the loudon heights into a sequestered valley, out of direct communication with the great world. after visiting one or two of the farmhouses, we came across a school by the roadside. it was the hour of recess, and the teacher was taking an active part in promoting the games in which the children were engaged. it was suggested by one of us that it would be of interest to see the methods of this school; so we approached the teacher on the subject, who very kindly offered to call his pupils together and show us his teaching. first, however, we began to question him as to the subjects of instruction. the curriculum seemed rather meagre, as he went over it. i do not think it went beyond the three r's. "but do you not teach grammar as well as reading?" i asked. "no, i am sorry to say, i do not. i did want to teach grammar, but the people all said that they had not been taught grammar, and had got along very well without it, and did not see why the time of the children should be taken up by it." "if you do not teach grammar from the book, you could at least teach it by practice in composition. do you not exercise them in writing compositions?" "i did try that once, and let me tell you how it turned out. they got up a story that i was teaching the children to write love letters, and made such a clamor about it that i had to stop." he then kindly offered to show us what he did teach. the school was called together and words to spell were given out from a dictionary. they had got as far as "patrimony," and went on from that word to a dozen or so that followed it. the words were spelled by the children in turn, but nothing was said about the definition or meaning of the word. he did not explain whether, in the opinion of the parents, it was feared that disastrous events might follow if the children knew what a "patrimony" was, but it seems that no objections were raised to their knowing how to spell it. we thanked him and took our leave, feeling that we were well repaid for our visit, however it might have been with the teacher and his school. i have never been able to confine my attention to astronomy with that exclusiveness which is commonly considered necessary to the highest success in any profession. the lawyer finds almost every branch of human knowledge to be not only of interest, but of actual professional value, but one can hardly imagine why an astronomer should concern himself with things mundane, and especially with sociological subjects. but there is very high precedent for such a practice. quite recently the fact has been brought to light that the great founder of modern astronomy once prepared for the government of his native land a very remarkable paper on the habit of debasing the currency, which was so prevalent during the middle ages. [1] the paper of copernicus is, i believe, one of the strongest expositions of the evil of a debased currency that had ever appeared. its tenor may be judged by the opening sentence, of which the following is a free translation:- innumerable though the evils are with which kingdoms, principalities, and republics are troubled, there are four which in my opinion outweigh all others,--war, death, famine, and debasement of money. the three first are so evident that no one denies them, but it is not thus with the fourth. a certain interest in political economy dates with me from the age of nineteen, when i read say's work on the subject, which was at that time in very wide circulation. the question of protection and free trade was then, as always, an attractive one. i inclined towards the free trade view, but still felt that there might be another side to the question which i found myself unable fully to grasp. i remember thinking it quite possible that smith's "wealth of nations" might be supplemented by a similar work on the strength of nations, in which not merely wealth, but everything that conduces to national power should be considered, and that the result of the inquiry might lead to practical conclusions different from those of smith. very able writers, among them henry c. carey, had espoused the side of protection, but for some years i had not time to read their works, and therefore reserved my judgment until more light should appear. thus the matter stood until an accident impelled me to look into the subject. about 1862 or 1863 president thomas hill, of harvard university, paid a visit to washington. i held him in very high esteem. he was a mathematician, and had been the favorite student of professor benjamin peirce; but i did not know that he had interested himself in political economy until, on the occasion in question, i passed an evening with him at the house where he was a guest. here he told me that in a public lecture at philadelphia, a few evenings before, he had informed his hearers that they had amongst them one of the greatest philosophers of the time, henry c. carey. he spoke of his works in such enthusiastic terms, describing especially his law of the tendency of mankind to be attracted towards the great capitals or other centres of population, that i lost no time in carefully reading carey's "principles of social science." the result was much like a slap in the face. with every possible predisposition to look favorably on its teachings, i was unable to find anything in them but the prejudiced judgments of a one-sided thinker, fond of brilliant general propositions which really had nothing serious to rest upon either in fact or reason. the following parody on his method occurred to me:-the physicians say that quinine tends to cure intermittent fever. if this be the case, then where people use most quinine, they will have least intermittent fever. but the facts are exactly the opposite. along the borders of the lower mississippi, where people take most quinine, they suffer most from fever; therefore the effect of quinine is the opposite of that alleged. i earnestly wished for an opportunity to discuss the matter further with mr. hill, but it was never offered. during the early years of the civil war, when the country was flooded with an irredeemable currency, i was so much disturbed by what seemed to me the unwisdom of our financial policy, that i positively envied the people who thought it all right, and therefore were free from mental perturbation on the subject. i at length felt that i could keep silent no longer, and as the civil war was closing, i devoted much time to writing a little book, "critical examination of our financial policy during the southern rebellion." i got this published by the appletons, but had to pay for the production. it never yielded enough to pay the cost of printing, as is very apt to be the case with such a hook when it is on the unpopular side and by an unknown author. it had, however, the pleasant result of bringing me into friendly relations with two of the most eminent financiers of the country, mr. hugh mcculloch and mr. george s. coe, the latter president of one of the principal banks of new york. the compliments which these men paid to the book were the only compensation i got for the time and money expended upon it. in 1876 the "north american review" published a centennial number devoted to articles upon our national progress during the first century of our existence. i contributed the discussion of our work in exact science. natural science had been cultivated among us with great success, but i was obliged to point out our backward condition in every branch of exact science, which was more marked the more mathematical the character of the scientific work. in pure mathematics we seemed hopelessly behind in the race. i suppose that every writer who discusses a subject with a view of influencing the thought of the public, must be more or less discouraged by the small amount of attention the best he can say is likely to receive from his fellow-men. no matter what his own opinion of the importance of the matters he discusses, and the results that might grow out of them if men would only give them due attention, they are lost in the cataract of utterances poured forth from the daily, weekly, and monthly press. i was therefore much pleased, soon after the article appeared, to be honored with a visit from president gilman, who had been impressed with my views, and wished to discuss the practicability of the johns hopkins university, which was now being organized, doing something to promote the higher forms of investigation among us. one of the most remarkable mathematicians of the age, professor j. j. sylvester, had recently severed his connection with the royal military academy at woolich, and it had been decided to invite him to the chair of mathematics at the new university. it was considered desirable to have men of similar world-wide eminence in charge of the other departments in science. but this was found to be impracticable, and the policy adopted was to find young men whose reputation was yet to be made, and who would be the leading men of the future, instead of belonging to the past. all my experience would lead me to say that the selection of the coming man in science is almost as difficult as the selection of youth who are to become senators of the united states. the success of the university in finding the young men it wanted, has been one of the most remarkable features in the history of the johns hopkins university. of this the lamented rowland affords the most striking, but by no means the only instance. few could have anticipated that the modest and scarcely known youth selected for the chair of physics would not only become the leading man of his profession in our country, but one of the chief promoters of scientific research among us. mathematical study and research of the highest order now commenced, not only at baltimore, but at harvard, columbia, and other centres of learning, until, to-day, we are scarcely behind any nation in our contributions to the subject. the development of economic study in our country during the last quarter of the last century is hardly less remarkable than that of mathematical science. a great impulse in this direction was given by professor r. t. ely, who, when the johns hopkins university was organized, became its leading teacher in economics. he had recently come from germany, where he had imbibed what was supposed to be a new gospel in economics, and he now appeared as the evangelist of what was termed the historical school. my own studies were of course too far removed from this school to be a factor in it. but, so far as i was able, i fought the idea of there being two schools, or of any necessary antagonism between the results of the two methods. it was true that there was a marked difference in form between them. some men preferred to reach conclusions by careful analysis of human nature and study of the acts to which men were led in seeking to carry out their own ends. this was called the old-school method. others preferred to study the problem on a large scale, especially as shown in the economic development of the country. but there could be no necessary difference between the conclusions thus reached. one curious fact, which has always been overlooked in the history of economics in our country, shows how purely partisan was the idea of a separation of the two schools. the fact is that the founder of the historic school among us, the man who first introduced the idea, was not ely, but david a. wells. up to the outbreak of the civil war, mr. wells had been a writer on scientific subjects without any special known leaning toward economies; but after it broke out he published a most noteworthy pamphlet, setting forth the resources of our country for carrying on war and paying a debt, in terms so strong as to command more attention than any similar utterance at the time. this led to his appointment as special commissioner of revenue, with the duty of collecting information devising the best methods of raising revenue. his studies in this line were very exhaustive, and were carried on by the methods of the historic school of economics. i was almost annoyed to find that, if any economic question was presented to him, he rushed off to the experience of some particular people or nation--it might be sweden or australia--instead of going down to fundamental principles. but i could never get him interested in this kind of analysis. one of professor ely's early movements resulted in the organization of the american economic association. his original plan was that this society should have something like a creed to which its members were expected to subscribe. a discussion of the whole subject appeared in the pages of "science," a number of the leading economists of the country being contributors to it. the outcome of the whole matter has been a triumph for what most men will now consider reason and good sense. the economic association was scarcely more than organized when it broke loose from all creeds and admitted into its ranks investigators of the subject belonging to every class. i think the last discussion on the question of two schools occurred at the new york meeting, about 1895, after which the whole matter was dropped and the association worked together as a unit. as professor ely is still a leader on the stage, i desire to do him justice in one point. i am able to do so because of what i have always regarded as one of the best features of the johns hopkins university--the unity of action which pervaded its work. there is a tendency in such institutions to be divided up into departments, not only independent of each other, but with little mutual help or sympathy. of course every department has the best wishes of every other, and its coöperation when necessary, but the tendency is to have nothing more than this. in 1884, after the resignation of professor sylvester, i was invited by president gilman to act as head of the department of mathematics. i could not figure as the successor of sylvester, and therefore suggested that my title should be professor of mathematics and astronomy. the examinations of students for the degree of doctor of philosophy were then, as now, all conducted by a single "board of university studies," in which all had equal powers, although of course no member of the board took an active part in cases which lay entirely outside of his field. but the general idea was that of mutual coöperation and criticism all through. each professor was a factor in the department of another in a helpful and not an antagonistic way, and all held counsel on subjects where the knowledge of all was helpful to each. i cannot but think that the wonderful success of the johns hopkins university is largely due to this feature of its activity, which tended to broaden both professors and students alike. in pursuance of this system i for several years took part in the examinations of students of economics for their degrees. i found that professor ely's men were always well grounded in those principles of economic theory which seemed to me essential to a comprehension of the subject on its scientific side. being sometimes looked upon as an economist, i deem it not improper to disclaim any part in the economic research of to-day. what i have done has been prompted by the conviction that the greatest social want of the age is the introduction of sound thinking on economic subjects among the masses, not only of our own, but of every other country. this kind of thinking i have tried to promote in our own country by such books as "a plain man's talk on the labor question," and "principles of political economy." my talks with professor henry used to cover a wide field in scientific philosophy. adherence to the presbyterian church did not prevent his being as uncompromising an upholder of modern scientific views of the universe as i ever knew. he was especially severe on the delusions of spiritualism. to a friend who once told him that he had seen a "medium" waft himself through a window, he replied, "judge, you never saw that; and if you think you did, you are in a dangerous mental condition and need the utmost care of your family and your physician." among the experiences which i heard him relate more than once, i think, was one with a noted medium. henry was quite intimate with president lincoln, who, though not a believer in spiritualism, was from time to time deeply impressed by the extraordinary feats of spiritualistic performers, and naturally looked to professor henry for his views and advice on the subject. quite early in his administration one of these men showed his wonderful powers to the president, who asked him to show professor henry his feats. although the latter generally avoided all contact with such men, he consented to receive him at the smithsonian institution. among the acts proposed was that of making sounds in various quarters of the room. this was something which the keen senses and ready experimental faculty of the professor were well qualified to investigate. he turned his head in various positions while the sounds were being emitted. he then turned toward the man with the utmost firmness and said, "i do not know how you make the sounds, but this i perceive very clearly: they do not come from the room but from your person." it was in vain that the operator protested that they did not, and that he had no knowledge how they were produced. the keen ear of his examiner could not be deceived. sometime afterward the professor was traveling in the east, and took a seat in a railway car beside a young man who, finding who his companion was, entered into conversation with him, and informed him that he was a maker of telegraph and electrical instruments. his advances were received in so friendly a manner that he went further yet, and confided to henry that his ingenuity had been called into requisition by spiritual mediums, to whom he furnished the apparatus necessary for the manifestations. henry asked him by what mediums he had been engaged, and was surprised to find that among them was the very man he had met at the smithsonian. the sounds which the medium had emitted were then described to the young man, who in reply explained the structure of the apparatus by which they were produced, which apparatus had been constructed by himself. it was fastened around the muscular part of the upper arm, and was so arranged that clicks would be produced by a simple contraction of the muscle, unaccompanied by any motion of the joints of the arm, and entirely invisible to a bystander. during the philadelphia meeting of the american association for the advancement of science, held in 1884, a few members were invited by one of the foreign visitors, professor fitzgerald of dublin, i think, to a conference on the subject of psychical research. the english society on this subject had been organized a few years before, and the question now was whether there was interest enough among us to lead to the organization of an american society for psychical research. this was decided in the affirmative; the society was soon after formed, with headquarters in boston, and i was elected its first president, a choice which powell, of washington, declared to be ridiculous in the highest degree. on accepting this position, my first duty was to make a careful study of the publications of the parent society in england, with a view of learning their discoveries. the result was far from hopeful. i found that the phenomena brought out lacked that coherence and definiteness which is characteristic of scientific truths. remarkable effects had been witnessed; but it was impossible to say, do so and so, and you will get such an effect. the best that could be said was, perhaps you will get an effect, but more likely you will not. i could not feel any assurance that the society, with all its diligence, had done more than add to the mass of mistakes, misapprehensions of fact, exaggerations, illusions, tricks, and coincidences, of which human experience is full. in the course of a year or two i delivered a presidential address, in which i pointed out the difficulties of the case and the inconclusiveness of the supposed facts gathered. i suggested further experimentation, and called upon the english society to learn, by trials, whether the mental influences which they had observed to pass from mind to mind under specially arranged conditions, would still pass when a curtain or a door separated the parties. fifteen years have since elapsed, and neither they nor any one else has settled this most elementary of all the questions involved. the only conclusion seems to be that only in exceptional cases does any effect pass at all; and when it does, it is just as likely to be felt halfway round the world as behind a curtain in the same room. shortly after the conference in philadelphia i had a long wished-for opportunity to witness and investigate what, from the descriptions, was a wonder as great as anything recorded in the history of psychic research or spiritualism. early in 1885 a tall and well-built young woman named lulu hurst, also known as the "georgia magnetic girl," gave exhibitions in the eastern cities which equaled or exceeded the greatest feats of the spiritualists. on her arrival in washington invitations were sent to a number of our prominent scientific men to witness a private exhibition which she gave in advance of her public appearance. i was not present, but some who attended were so struck by her performance that they arranged to have another exhibition in dr. graham bell's laboratory. i can give the best idea of the case if i begin with an account of the performance as given by the eye-witnesses at the first trial. we must remember that this was not the account of mere wonder-seekers, but of trained scientific men. their account was in substance this:-a light rod was firmly held in the hands of the tallest and most muscular of the spectators. miss lulu had only to touch the rod with her fingers when it would begin to go through the most extraordinary manoeuvres. it jerked the holder around the room with a power he was unable to resist, and finally threw him down into a corner completely discomfited. another spectator was then asked to take hold of the rod, and miss lulu extended her arms and touched each end with the tip of her finger. immediately the rod began to whirl around on its central axis with such force that the skin was nearly taken off the holder's hands in his efforts to stop it. a heavy man being seated in a chair, man and chair were lifted up by the fair performer placing her hands against the sides. to substantiate the claim that she herself exerted no force, chair and man were lifted without her touching the chair at all. the sitter was asked to put his hands under the chair; the performer put her hands around and under his in such a way that it was impossible for her to exert any force on the chair except through his hands. the chair at once lifted him up without her exerting any pressure other than the touch upon his hands. several men were then invited to hold the chair still. the performer then began to deftly touch it with her finger, when the chair again began to jump about in spite of the efforts of three or four men to hold it down. a straw hat being laid upon a table crown downwards, she laid her extended hands over it. it was lifted up by what seemed an attractive force similar to that of a magnet upon an armature, and was in danger of being torn to pieces in the effort of any one holding it to keep it down, though she could not possibly have had any hold upon the object. among the spectators were physicians, one or more of whom grasped miss lulu's arms while the motions were going on, without finding any symptoms of strong muscular action. her pulse remained normal throughout. the objects which she touched seemed endowed with a force which was wholly new to science. so much for the story. now for the reality. the party appeared at the volta laboratory, according to arrangement. those having the matter in charge were not professional mystifiers of the public, and showed no desire to conceal anything. there was no darkening of rooms, no putting of hands under tables, no fear that spirits would refuse to act because of the presence of some skeptic, no trickery of any sort. we got up such arrangements as we could for a scientific investigation of the movements. one of these was a rolling platform on which miss lulu was requested to stand while the forces were exerted. another device was to seat her on a platform scale while the chair was lifting itself. these several experiments were tried in the order in which i have mentioned them. i took the wonderful staff in my hands, and miss lulu placed the palms of her hands and extended them against the staff near the ends, while i firmly grasped it with my two hands in the middle. of course this gave her a great advantage in the leverage. i was then asked to resist the staff with all my force, with the added assurance from mrs. hurst, the mother, that the resistance would be in vain. although the performer began with a delicate touch of the staff, i noticed that she changed the position of her hands every moment, sometimes seizing the staff with a firm grip, and that it never moved in any direction unless her hands pressed it in that direction. as nearly as i could estimate, the force which she exerted might have been equal to forty pounds, and this exerted first in one way and then in another was enough to upset the equilibrium of any ordinary man, especially when the jerks were so sudden and unexpected that it was impossible for one to brace himself against them. after a scene of rather undignified contortion i was finally compelled to retire in defeat, but without the slightest evidence of any other force than that exerted by a strong, muscular young woman. i asked that the rod might be made to whirl in my hands in the manner which has been described, but there was clearly some mistake in this whirl, for miss lulu knew nothing on the subject. then we proceeded to the chair performance, which was repeated a number of times. i noticed that although, at the beginning, the sitter held his fingers between the chair and the fingers of the performer, the chair would not move until miss lulu had the ball of her hand firmly in connection with it. even then it did not actually lift the sitter from the ground, but was merely raised up behind, the front legs resting on the ground, whereupon the sitter was compelled to get out. this performance was repeated a number of times without anything but what was commonplace. in order to see whether, as claimed, no force was exerted on the chair, the performer was invited to stand on the platform of the scales while making the chair move. the weights had been so adjusted as to balance a weight of forty pounds above her own. the result was that after some general attempts to make the chair move the lever clicked, showing that a lifting force exceeding forty pounds was being exerted by the young woman on the platform. the click seemed to demoralize the operator, who became unable to continue her efforts. the experiment of raising a hat turned out equally simple, and the result of all the trials was only to increase my skepticism as to the whole doctrine of unknown forces and media of communication between one mind and another. i am now likely to remain a skeptic as to every branch of "occult science" until i find some manifestation of its reality more conclusive than any i have yet been able to find. [1] prowe: nicolaus copernicus, bd. ii. (berlin, 1884), p. 33. index absence of mind, examples of, 73, 169. academy of science, a would-be, 351. academy of sciences, paris, 327. adams, prof. john c., 220; intellectual capacity, 282; politics, 283. agnesi, donna maria, 294. agassiz, louis, discusses origin of species, 70. airy, sir george b., observations of transit of venus, 166; hospitality, 285; poetic taste, 286; executive ability, 286; methods of works, 289. alexander, columbus, 368. anderson, sir james, 300. angle, trisection of, 387. argelander, prof., master of observational astronomy, 318, 319. atlantic cable, the first, 300. auwers, the great astronomer, 306. bacon, mr., teacher at bedeque, 9. baillie, william, u. s. engineer, 361. baird, spencer f., 240. bancroft, george, reviews judicial decision of star catalogue case, 378. barnard, e. e., 190. barnard, gen. john g., 335. bartlett, william p. g., 83. belknap, admiral g. h., 228. bell, alexander graham, tries to locate ball in garfield's body, 358. black, jeremiah, 168, 169. blackie, prof. j. s., 294. bond, george p., 250. booth, edwin, 157. borst, charles a., 373. boss, prof. lewis, 124, 230. bowditch, nathaniel, 1. bradford, isaac, 74. brewster, elder, 3. brown, prof. s. j., 125. burnham, s. w., 188. campbell, william w., 190. carey, henry c., 400. cassey, thomas l., jr., 174. casserly, eugene, 128. cassini, astronomer, of paris observatory, 331. cayley, prof. arthur, 280. chandler, captain ralph, u. s. n., 171. chandler, w. e., 126. chauvenet, william, 111. chevreul, m., his remarkable age, 327. circle, quadrature of, 387. clark, alvan, 129, 144. clark, alvan, & sons, character of the firm, 147. cleveland, keith, 224. cobbett, william, 7, 53. coe, george s., financier, 402. coffin, j. h. c., 111. combe, george, 4, 16. commune of paris, 321-326. comstock, g. c., 126. cooke, thomas, & sons, 133. cox, jacob d., 258. crank, the anti-gravitation, 381; a reasonable, 383. cranks, specimen letters from, 389. darwin's "origin of species," discussion of, 70. dawes, henry l., 82. dawes, rev. w. r., 148. davis, charles h., 63; becomes superintendent at naval observatory, 107. dayton, a. g., 126. delaunay, charles, indorses prof. newcomb, 317; director of paris observatory, 319; attractive personality, 329, 330. draper, dr. henry, expert in astronomical photography, 171, 223. draper, dr. john w., 250. dudley observatory troubles, 80. early, gen. jubal a., raid of, 339. eastman, john r., 107, 274. eclipse, solar, of 1860, journey to observe, 88. economics, studies in, 399; alleged schools of, 405. education in mountain regions of south, 397. eggleston, edward, 89. eliot, charles w., 74. elkin, dr. w. l., 176. elliot, benjamin s., 50. ely, prof. r. t., as economist, 404; organizes american economic association, 406; merits as a teacher, 408. evarts, william m., 241. eveleth, g. w., 55. feil, maker of optical discs, 185. ferguson, james, 111. ferrell, william, 72, 88. field, cyrus w., 128. fiske, john, on eccentric literature, 382. fixed stars, paris conference regarding, 230. floyd, richard s., 186. france, universities of, 392. franklin, admiral, 122. furber, mr., starts movement for admission of american students in french universities, 396. garfield, james a., first acquaintance with, 353; his early life, 354; injustice done him, 354; his intellectual gifts, 355; assassination of, 356. geological survey, circumstances leading to origin of, 252-255; attacks on, 261. gibraltar, determination of the longitude of, 284, 299. gill, sir david, 176. gillis, capt. j. m., superintendent of naval observatory, 99; obtains new transit circle, 105. gilman, daniel c., 403. gladstone, william ewart, meeting with, 273, 276. glaisher, j. w. l., 72. goldsborough, admiral, 340. gould, benjamin a., personality, 78; dudley observatory directorship, 80; candidate for naval observatory director, 111. gould, dr. e. r. l., 393. gravitation, detestable to some minds, 381. green, capt. f. m., 284. greenwich observatory, situation, 285; value of observations at, 288. grubb, sir howard j., 156, 185. hagar, judge, 189. hale, eugene p., 123. hale, george e., 126. hall, asaph, 107; discovers satellites of mars, 141. hamlin, hannibal, 128. harkness, william, appointed to naval observatory, 107; shares honor of discovering brightest line in spectrum of sun's corona, 113; director of observatory, 180. harrington, attorney, 367. harvard observatory, prof. newcomb called to directorship of, 211; pickering's directorship, 212. hassler, j. j. s., 264. hansen, prof., greatest master of celestial mechanics, 315, 316. hayden, prof. f. v., 253. hayes, rutherford b., 242, 259. hedrick, prof., 73. hell, father maximilian, his alleged forgery, 154. henry, prof. joseph, prof. newcomb's relations with, 1, 54, 58, 161; characteristics, 234-237; on spiritualism, 408. herbert, hilary a., 231. hewitt, a. s., 255. hilgard, j. e., 1, 59; in charge of coast survey, 65, 128. hill, george w., 218, 219, 221. hill, thomas prescott, 400. holcombe, lieut. j. h. l., 174. holden, prof. e. s., 184-194. horsford, e. n., 74. hubbard, prof. j. s., head astronomer of naval observatory, 98; in charge of mural circle, 102. huggins, sir william, 279. hughes, thomas, 272. humphreys, gen., chief of engineers, 256. hurst, lulu, the "georgia magnetic girl," exhibitions of, 412-416. illusion, an astronomical, 137. inch, richard, united states engineer, 361. jennings, mr., cooling device of, 358. jewett, c. c., 237. keeler, james e., 191. kelvin, lord, 248. kerr, prof., 73. king, clarence, 258, 259. knobel, e. b., 380. koresh, his theory, 385. lamar, judge lucius, 264. langley, prof. samuel p., 240. language, advantage of not knowing a, 306. laplace, the "mécanique céleste" of, 1. lardner's "popular lectures on science and art," 19. lawrence, prof. smith j., 56. lee, gen. robert e., 339. lee's "tables and formulæ," 56. leverrier, m., two views of, 328; meeting with, 330; his merits, 331. leverrier and hansen's systems of planetary computation, 219. lick, james, 182. lick observatory, origin of, 182; location discussed, 187; telescope at, 185; holden's administration, 192; keeler's administration, 194; campbell's administration, 194. lincoln, pres., his war-time receptions, 342; assassination of, 344; trial of assassins, 345. lister, lord, 278. litchfield observatory, founder of, 374. loomis, e. j., 74. lowe, mr. (viscount sherbrooke), 276. mahan, prof. d. h., 335. mars, discovery of the satellites of, 141. marsh, prof. o. c., exposure of indian ring, 263; relation to "wild west," 265; exposure of cardiff giant, 266; his modern fossil, 269. maskelyne, rev. nevil, 152. "mathematical monthly," foundation of, 84. mathematics and exact sciences, state of, in america, 402. maury, matthew f., work of, 103. mccook, gen. a. d., 341. mccormick, l. j., 132. mcculloch, hugh, 244, 402. mcmickan, captain, of cunard line, 271. mctavish, governor, 91. "mécanique céleste," first sight of, 56. meier, john, 223. meridian conference of 1884, 226. mill, john stuart, 272. mills, d. o., 183. miner and tully's "fevers of the connecticut valley," 33. monroe, rev. alexander h., 36 n. moore, capt. w. s., 361. moore's navigator, 17. morrill, justin s., 124. national academy of science, early proceedings, 251; report of geological survey, 255; report of forestry system, 261. "national intelligencer," letter in, 55. natural philosophy, mrs. marcet's conversations on, 18. nautical almanac, assistants on, 66; in charge of, 120. naval observatory, early history of, 102; work at, 109; conditions at, 110; civilian head proposed, 111; views of administration in regard to, 112; reports of eclipse of 1870, 113; visit of emperor dom pedro, 117; efforts to improve, 122; board of visitors appointed, 126; telescope of, 128; congressional action regarding new telescope, 131; observations of satellites of neptune, 136, 141; search for companion of procyon, 138. negro, characteristics of, 346; education of, 348. neptune, observation of the satellites of, 136, 141. newall, r. s., 133. newcomb, john, father of simon, characteristics and marriage, 4. newcomb, simon, the first, 2. newcomb, judge simon b., 2. newcomb, prof. simon, ancestry, 2, 3; parentage, 6; early education at bedeque, 9; begins study of arithmetic, 10; influence of books, 14-22; winter spent with farmer jefferson, 18; residence at yarmouth, 23; ancestral home, 23; begins study of medicine, 27; manufacture of botanic medicine under dr. foshay, 31, 32; joins temperance lodge, 37; intimacy with parkin family, 39; first sight of smithsonian, 52; reading in political economy, 53; study of newton's "principia," 54; first attempt at mathematical paper, 54; letter in "national intelligencer," 55; colonel abert sends lee's "tables and formulæ," 56; letter from prof. l. j. smith, 56; teaching in a planter's family, 56; first sight of "mécanique céleste," 56; assistant on staff of nautical almanac, 66; discussion of darwin's "origin of species," 70; student in lawrence scientific school, 74; acquaintance with dr. b. a. gould, 78; friendship with william p. g. bartlett, 83; journey in 1860 to observe solar eclipse, 88; meets governor ramsey and edward eggleston, 89; received by governor mctavish, 91; saskatchewan journey, 92; candidate for professorship in washington university, 95; application for professorship in naval observatory, 97; early experience at observatory, 101; edits yarnall's observations, 105; in charge of mural circle, 107; journey to observe 1869 eclipse, 113; new transit circle, 114; investigation of moon's motion, 115; visit of dom pedro to observatory, 117; assumes charge of nautical almanac office, 120; verification of satellites of mars, 141; transit of venus expedition to europe, 167; expedition to cape of good hope, 174; agent of lick observatory trustees, 184; first meeting with schaeberle, 190; study of orbits of asteroids, 195; problems of astronomy, 198; motion of moon, 202; occultations of stars, 207; offered harvard observatory directorship, 211; head of nautical almanac office, 214; policy of office, 216, 233; computations for planet tables, 216; assistants, 218; suggestions to meridian conference, 226; computations regarding fixed stars, 230; member yale alumni association, 241; member washington scientific club, 244; first trip to europe, 271; meets thomas hughes, 272; john stuart mill, 272; william ewart gladstone, 273; general burnside, 273; attends banquet of royal society, 276; visit to lord lister, 278; meets prof. cayley, 280; prof. j. c. adams calls, 281; determination of gibraltar longitude, 284; visits greenwich, 285; friendship with sir george airy, 285-289; visits edinburgh, 292; meets prof. blackie, 294; joins party of english astronomers bound for algeria, 295; stormy voyage, 296; at gibraltar, 297; sir james anderson, an old acquaintance, 300; mediterranean trip, 302-305; wilhelm förster, a berlin acquaintance, 306; meets great astronomer auwers, 306; visits pulkova observatory, 309; winter ride in russia, 310; first meeting with hansen, 315; arrives in paris during german evacuation, 319; visits paris observatory, 321; meets leverrier, 330; washington during civil war and after, 334-371; two days military service, 339; assassination of lincoln, 344; attends trial of conspirators, 345; acquaintance with sumner, 349; with president garfield, 353; asked to device means for cooling his sick chamber, 357; suggestions for location of bullet, 358; experience with eccentric theorists, 381-389; assists in obtaining entrance of american students to french universities, 396; object lesson in regard to education in mountain regions of south, 397; studies in economics, 399; publishes "critical examination of our financial policy during the southern rebellion," 402; contribution to "north american review," 402; conference with prof. daniel c. gilman, 403; contributions to economic literature: "a plain man's talk on the labor question," "principles of political economy," 408; "psychical research," 410-412. nixon, thomas, 37, 41. occultism, 93. old peake, janitor of the smithsonian, 58. oldright, mr., 53. oliver, james e., 72. ommaney, sir erastus, 295. paine, thomas, 3. paradoxers, experience with, 382. paris conference, conclusions of, 230; attacked by prof. boss and s. c. chandler, 230. paris observatory, 321, 332. parkin, george r., 39. patent claim, a curious, 361. patterson, j. w., 352. peirce, benjamin professor of mathematics, 75; personality, 77, 78; chairman of committee on methods of observing transit of venus, 161; director of solar eclipse expedition, 274; presence in england valuable to british astronomers, 277. peters, c. h. f., heads transit of venus expedition, 139; star catalogue case, 372; work on ptolemy's catalogue, 380. photoheliograph, horizontal 164. phrenology, study of, 14, 34. pickering, e. c., 126. pistor and martin's transit circle, 105. poe, gen. o. m., 352. powell, john w., 240; during garfield's illness, 357. "principia," newton's, 54. procyon, search for companion of, 138; at lick observatory, 140. professors in navy, origin of corps of, 101. "psychical research," 410. ptolemy's star catalogue, peter's work on, 380. pulkova observatory, object glass made by alvan clark & sons, 144, 145; foundation and situation, 309-313. reed, thomas b., 125. rhodes scholarships, 37. rodgers, admiral john, 120. rogers, william b., 250. royal society, banquet of, 275. runkle, john d., 1, 66. safe burglary conspiracy, 367. safford, truman h., 67. sampson, admiral w. t., 121. sands, admiral, superintendent of naval observatory, 112; retirement, 116; assists in obtaining new telescope, 130. sauty, de, cable operator at gibraltar, 300. schaeberle, assistant to prof. holden, 190. schofield, j. m., 96. schurman, caleb, 11. schurman, jacob gould, 11 n. scientific club, 244. scudder, samuel h., 88. shepherd, alexander h., career, 364-371. sherman, gen. w. t., 243. sibley, j. langdon, 76. smith, james, circle squarer, 387. smithson, james, 235. smithsonian institution, policy of, 235, 236; difficulties in administration, 237; expansion of scope, 240. smyth, prof. c. piazzi, 293. smyth, admiral, w. h., 152. sophocles, evangelinus apostolides, 75. standard time, adoption of, 225, 226. stanton, edwin m., 336; his tireless energy, 337; his law of war, 338. star catalogue case, the great, 372. steeves, isaac, 38. struve, otto, 144, 309. struve, wilhelm, 312. struve, russian minister at washington, 312. sudler, dr. arthur e., 50. sumner, charles, characteristics, 349, 350; kills an incipient "academy," 352. sylvester, prof. j. j., 403. telescope, horizontal, planned by prof. winlock, 163. thomson, sir william, 248. tilley, sir leonard, 40. tracy, benjamin, 123. transit of venus, early observations of, 151; observed by mason and dixon, 153; hell's alleged forgeries, 157; preparation for observation of, 160; committee of national academy of sciences to consider subject, 161; transit commission, 163; appropriation for observation station, 170, 171, 174; value of observations, 173; observations at cape town, 177; publication of observations, 178. tremblay, dom de la, 395. tuttle, h. p., 192. tyndall, prof., 296. van vleck, prof., 73. wagner, dr., 315. wallace, gen. lew, 339. washburn, mr., minister to paris, 320. washington, during the civil war, 334; newsboys of, 336; early's raid on, 339; after the fall of richmond, 343; shepherd régime, 363; the new city, 366. weiss, director of vienna observatory, 157. welles, gideon, 111. wells, david a., 405. white house, incidents at, during garfield's illness, 357. whitney, william c., 123. williams, sir fenwick, 298. wilson, henry, 250. winlock, prof. joseph, superintendent nautical almanac, 59, 61; personality, 65; constructs instrument for astronomical photography, 163. wolf, prof. charles, 144. woodward, dr. j. j., 357. wright, chauncey, 70. wright, gen. h. g., 341. yale alumni association, 241. yarnall, prof. m., characteristics, 101; observations of, 105. transcriber's note the punctuation and spelling from the original text have been faithfully preserved. only obvious typographical errors have been corrected. there are several mathematical formulas within the text. they are represented as follows: superscripts: x^3 subscripts: x_3 square root: [square root] greek letters: [pi], [theta]. greek star names are represented as [alpha], [gamma], for example. pioneers of science [illustration] [illustration: newton _from the picture by kneller, 1689, now at cambridge_] pioneers of science by oliver lodge, f.r.s. professor of physics in victoria university college, liverpool _with portraits and other illustrations_ london macmillan and co. and new york 1893 richard clay and sons, limited, london and bungay. preface this book takes its origin in a course of lectures on the history and progress of astronomy arranged for me in the year 1887 by three of my colleagues (a.c.b., j.m., g.h.r.), one of whom gave the course its name. the lectures having been found interesting, it was natural to write them out in full and publish. if i may claim for them any merit, i should say it consists in their simple statement and explanation of scientific facts and laws. the biographical details are compiled from all readily available sources, there is no novelty or originality about them; though it is hoped that there may be some vividness. i have simply tried to present a living figure of each pioneer in turn, and to trace his influence on the progress of thought. i am indebted to many biographers and writers, among others to mr. e.j.c. morton, whose excellent set of lives published by the s.p.c.k. saved me much trouble in the early part of the course. as we approach recent times the subject grows more complex, and the men more nearly contemporaries; hence the biographical aspect diminishes and the scientific treatment becomes fuller, but in no case has it been allowed to become technical and generally unreadable. to the friends (c.c.c., f.w.h.m., e.f.r.) who with great kindness have revised the proofs, and have indicated places where the facts could be made more readily intelligible by a clearer statement, i express my genuine gratitude. university college, liverpool, _november, 1892_. contents _part i_ lecture i page copernicus and the motion of the earth 2 lecture ii tycho brahé and the earliest observatory 32 lecture iii kepler and the laws of planetary motion 56 lecture iv galileo and the invention of the telescope 80 lecture v galileo and the inquisition 108 lecture vi descartes and his theory of vortices 136 lecture vii sir isaac newton 159 lecture viii newton and the law of gravitation 180 lecture ix newton's "principia" 203 _part ii_ lecture x roemer and bradley and the velocity of light 232 lecture xi lagrange and laplace--the stability of the solar system, and the nebular hypothesis 254 lecture xii herschel and the motion of the fixed stars 273 lecture xiii the discovery of the asteroids 294 lecture xiv bessel--the distances of the stars, and the discovery of stellar planets 304 lecture xv the discovery of neptune 317 lecture xvi comets and meteors 331 lecture xvii the tides 353 lecture xviii the tides, and planetary evolution 379 illustrations fig. page 1. archimedes 8 2. leonardo da vinci 10 3. copernicus 12 4. homeric cosmogony 15 5. egyptian symbol of the universe 16 6. hindoo earth 17 7. order of ancient planets corresponding to the days of the week 19 8. ptolemaic system 20 9. specimens of apparent paths of venus and of mars among the stars 21 10. apparent epicyclic orbits of jupiter and saturn 22 11. egyptian system 24 12. true orbits of earth and jupiter 25 13. orbits of mercury and earth 25 14. copernican system as frequently represented 26 15. slow movement of the north pole in a circle among the stars 29 16. tychonic system, showing the sun with all the planets revolving round the earth 38 17. portrait of tycho 41 18. early out-door quadrant of tycho 43 19. map of denmark, showing the island of huen 45 20. uraniburg 46 21. astrolabe 47 22. tycho's large sextant 48 23. the quadrant in uraniburg 49 24. tycho's form of transit circle 50 25. a modern transit circle 51 26. orbits of some of the planets drawn to scale 60 27. many-sided polygon or approximate circle enveloped by straight lines 61 28. kepler's idea of the regular solids 62 29. diagram of equant 67 30. excentric circle supposed to be divided into equal areas 68 31. mode of drawing an ellipse 70 32. kepler's diagram proving equable description of areas for an ellipse 71 33. diagram of a planet's velocity in different parts of its orbit 72 34. portrait of kepler 76 35. curve described by a projectile 82 36. two forms of pulsilogy 87 37. tower of pisa 91 38. view of the half-moon in small telescope 97 39. portion of the lunar surface more highly magnified 98 40. another portion of the lunar surface 99 41. lunar landscape showing earth 100 42. galileo's method of estimating the height of lunar mountain 101 43. some clusters and nebulæ 102 44. stages of the discovery of jupiter's satellites 103 45. eclipses of jupiter's satellites 105 46. old drawings of saturn by different observers, with the imperfect instruments of that day 111 47. phases of venus 112 48. sunspots as seen with low power 113 49. a portion of the sun's disk as seen in a powerful modern telescope 114 50. saturn and his rings 115 51. map of italy 118 52. portrait of galileo 126 53. portrait of descartes 148 54. descartes's eye diagram 151 55. descartes's diagram of vortices from his "principia" 152 56. manor-house of woolsthorpe 162 57. projectile diagram 170 58. } { 171 59. } diagrams illustrative of those near the beginning { 174 60. } of newton's "principia" { 175 61-2. } { 175 63. prismatic dispersion 182 64. a single constituent of white light is capable of no more dispersion 183 65. parallel beam passing through a lens 184 66. newton's telescope 186 67. the sextant, as now made 187 68. newton when young 196 69. sir isaac newton 200 70. another "principia" diagram 207 71. well-known model exhibiting the oblate spheroidal form as a consequence of spinning about a central axis 219 72. jupiter 221 73. diagram of eye looking at a light reflected in a distant mirror through the teeth of a revolving wheel 238 74. fizeau's wheel, showing the appearance of distant image seen through its teeth 239 75. eclipses of one of jupiter's satellites 241 76. a transit instrument for the british astronomical expedition, 1874 243 77. diagram of equatorially mounted telescope 245 78. aberration diagram 250 79. showing the three conjunction places in the orbits of jupiter and saturn 259 80. lord rosse's drawing of the spiral nebula in canes venatici 269 81. saturn 271 82. principle of newtonian reflector 278 83. herschel's 40-foot telescope 283 84. william herschel 285 85. caroline herschel 287 86. double stars 288 87. old drawing of the cluster in hercules 290 88. old drawing of the andromeda nebula 291 89. the great nebula in orion 292 90. planetary orbits to scale 297 91. diagram illustrating parallax 307 92. the königsberg heliometer 312 93. perturbations of uranus 320 94. uranus' and neptune's relative positions 325 95. meteorite 333 96. meteor stream crossing field of telescope 334 97. diagram of direction of earth's orbital motion 335 98. parabolic and elliptic orbits 340 99. orbit of halley's comet 341 100. various appearances of halley's comet when last seen 342 101. head of donati's comet of 1858 343 102. comet 344 103. encke's comet 345 104. biela's comet as last seen in two portions 346 105. radiant point perspective 348 106. present orbit of november meteors 349 107. orbit of november meteors before and after encounter with uranus 351 108. the mersey 355 109. co-tidal lines, showing the way the tidal wave reaches the british isles from the atlantic 359 110. whirling earth model 364 111. earth and moon model 365 112. earth and moon (earth's rotation neglected) 366 113. maps showing how comparatively free from land obstruction the ocean in the southern hemisphere is 369 114. spring and neap tides 370 115. tidal clock 371 116. sir william thomson (lord kelvin) 373 117. tide-gauge for recording local tides 375 118. harmonic analyzer 375 119. tide-predicter 376 120. weekly sheet of curves 377 pioneers of science part i _from dusk to daylight_ dates and summary of facts for lecture i _physical science of the ancients._ thales 640 b.c., anaximander 610 b.c., pythagoras 600 b.c., anaxagoras 500 b.c., eudoxus 400 b.c., aristotle 384 b.c., aristarchus 300 b.c., archimedes 287 b.c., eratosthenes 276 b.c., hipparchus 160 b.c., ptolemy 100 a.d. _science of the middle ages._ cultivated only among the arabs; largely in the forms of astrology, alchemy, and algebra. _return of science to europe._ roger bacon 1240, leonardo da vinci 1480, (printing 1455), columbus 1492, copernicus 1543. _a sketch of copernik's life and work._ born 1473 at thorn in poland. studied mathematics at bologna. became an ecclesiastic. lived at frauenburg near mouth of vistula. substituted for the apparent motion of the heavens the real motion of the earth. published tables of planetary motions. motion still supposed to be in epicycles. worked out his ideas for 36 years, and finally dedicated his work to the pope. died just as his book was printed, aged 72, a century before the birth of newton. a colossal statue by thorwaldsen erected at warsaw in 1830. pioneers of science lecture i copernicus and the motion of the earth the ordinary run of men live among phenomena of which they know nothing and care less. they see bodies fall to the earth, they hear sounds, they kindle fires, they see the heavens roll above them, but of the causes and inner working of the whole they are ignorant, and with their ignorance they are content. "understand the structure of a soap-bubble?" said a cultivated literary man whom i know; "i wouldn't cross the street to know it!" and if this is a prevalent attitude now, what must have been the attitude in ancient times, when mankind was emerging from savagery, and when history seems composed of harassments by wars abroad and revolutions at home? in the most violently disturbed times indeed, those with which ordinary history is mainly occupied, science is quite impossible. it needs as its condition, in order to flourish, a fairly quiet, untroubled state, or else a cloister or university removed from the din and bustle of the political and commercial world. in such places it has taken its rise, and in such peaceful places and quiet times true science will continue to be cultivated. the great bulk of mankind must always remain, i suppose, more or less careless of scientific research and scientific result, except in so far as it affects their modes of locomotion, their health and pleasure, or their purse. but among a people hurried and busy and preoccupied, some in the pursuit of riches, some in the pursuit of pleasure, and some, the majority, in the struggle for existence, there arise in every generation, here and there, one or two great souls--men who seem of another age and country, who look upon the bustle and feverish activity and are not infected by it, who watch others achieving prizes of riches and pleasure and are not disturbed, who look on the world and the universe they are born in with quite other eyes. to them it appears not as a bazaar to buy and to sell in; not as a ladder to scramble up (or down) helter-skelter without knowing whither or why; but as a fact--a great and mysterious fact--to be pondered over, studied, and perchance in some small measure understood. by the multitude these men were sneered at as eccentric or feared as supernatural. their calm, clear, contemplative attitude seemed either insane or diabolic; and accordingly they have been pitied as enthusiasts or killed as blasphemers. one of these great souls may have been a prophet or preacher, and have called to his generation to bethink them of why and what they were, to struggle less and meditate more, to search for things of true value and not for dross. another has been a poet or musician, and has uttered in words or in song thoughts dimly possible to many men, but by them unutterable and left inarticulate. another has been influenced still more _directly_ by the universe around him, has felt at times overpowered by the mystery and solemnity of it all, and has been impelled by a force stronger than himself to study it, patiently, slowly, diligently; content if he could gather a few crumbs of the great harvest of knowledge, happy if he could grasp some great generalization or wide-embracing law, and so in some small measure enter into the mind and thought of the designer of all this wondrous frame of things. these last have been the men of science, the great and heaven-born men of science; and they are few. in our own day, amid the throng of inventions, there are a multitude of small men using the name of science but working for their own ends, jostling and scrambling just as they would jostle and scramble in any other trade or profession. these may be workers, they may and do advance knowledge, but they are never pioneers. not to them is it given to open out great tracts of unexplored territory, or to view the promised land as from a mountain-top. of them we shall not speak; we will concern ourselves only with the greatest, the epoch-making men, to whose life and work we and all who come after them owe so much. such a man was thales. such was archimedes, hipparchus, copernicus. such pre-eminently was newton. now i am not going to attempt a history of science. such a work in ten lectures would be absurd. i intend to pick out a few salient names here and there, and to study these in some detail, rather than by attempting to deal with too many to lose individuality and distinctness. we know so little of the great names of antiquity, that they are for this purpose scarcely suitable. in some departments the science of the greeks was remarkable, though it is completely overshadowed by their philosophy; yet it was largely based on what has proved to be a wrong method of procedure, viz the introspective and conjectural, rather than the inductive and experimental methods. they investigated nature by studying their own minds, by considering the meanings of words, rather than by studying things and recording phenomena. this wrong (though by no means, on the face of it, absurd) method was not pursued exclusively, else would their science have been valueless, but the influence it had was such as materially to detract from the value of their speculations and discoveries. for when truth and falsehood are inextricably woven into a statement, the truth is as hopelessly hidden as if it had never been stated, for we have no criterion to distinguish the false from the true. [illustration: fig. 1.--archimedes.] besides this, however, many of their discoveries were ultimately lost to the world, some, as at alexandria, by fire--the bigoted work of a mohammedan conqueror--some by irruption of barbarians; and all were buried so long and so completely by the night of the dark ages, that they had to be rediscovered almost as absolutely and completely as though they had never been. some of the names of antiquity we shall have occasion to refer to; so i have arranged some of them in chronological order on page 4, and as a representative one i may specially emphasize archimedes, one of the greatest men of science there has ever been, and the father of physics. the only effective link between the old and the new science is afforded by the arabs. the dark ages come as an utter gap in the scientific history of europe, and for more than a thousand years there was not a scientific man of note except in arabia; and with the arabs knowledge was so mixed up with magic and enchantment that one cannot contemplate it with any degree of satisfaction, and little real progress was made. in some of the _waverley novels_ you can realize the state of matters in these times; and you know how the only approach to science is through some arab sorcerer or astrologer, maintained usually by a monarch, and consulted upon all great occasions, as the oracles were of old. in the thirteenth century, however, a really great scientific man appeared, who may be said to herald the dawn of modern science in europe. this man was roger bacon. he cannot be said to do more than herald it, however, for we must wait two hundred years for the next name of great magnitude; moreover he was isolated, and so far in advance of his time that he left no followers. his own work suffered from the prevailing ignorance, for he was persecuted and imprisoned, not for the commonplace and natural reason that he frightened the church, but merely because he was eccentric in his habits and knew too much. the man i spoke of as coming two hundred years later is leonardo da vinci. true he is best known as an artist, but if you read his works you will come to the conclusion that he was the most scientific artist who ever lived. he teaches the laws of perspective (then new), of light and shade, of colour, of the equilibrium of bodies, and of a multitude of other matters where science touches on art--not always quite correctly according to modern ideas, but in beautiful and precise language. for clear and conscious power, for wide-embracing knowledge and skill, leonardo is one of the most remarkable men that ever lived. about this time the tremendous invention of printing was achieved, and columbus unwittingly discovered the new world. the middle of the next century must be taken as the real dawn of modern science; for the year 1543 marks the publication of the life-work of copernicus. [illustration: fig. 2.--leonardo da vinci.] nicolas copernik was his proper name. copernicus is merely the latinized form of it, according to the then prevailing fashion. he was born at thorn, in polish prussia, in 1473. his father is believed to have been a german. he graduated at cracow as doctor in arts and medicine, and was destined for the ecclesiastical profession. the details of his life are few; it seems to have been quiet and uneventful, and we know very little about it. he was instructed in astronomy at cracow, and learnt mathematics at bologna. thence he went to rome, where he was made professor of mathematics; and soon afterwards he went into orders. on his return home, he took charge of the principal church in his native place, and became a canon. at frauenburg, near the mouth of the vistula, he lived the remainder of his life. we find him reporting on coinage for the government, but otherwise he does not appear as having entered into the life of the times. he was a quiet, scholarly monk of studious habits, and with a reputation which drew to him several earnest students, who received _vivâ voce_ instruction from him; so, in study and meditation, his life passed. he compiled tables of the planetary motions which were far more correct than any which had hitherto appeared, and which remained serviceable for long afterwards. the ptolemaic system of the heavens, which had been the orthodox system all through the christian era, he endeavoured to improve and simplify by the hypothesis that the sun was the centre of the system instead of the earth; and the first consequences of this change he worked out for many years, producing in the end a great book: his one life-work. this famous work, "de revolutionibus orbium coelestium," embodied all his painstaking calculations, applied his new system to each of the bodies in the solar system in succession, and treated besides of much other recondite matter. towards the close of his life it was put into type. he can scarcely be said to have lived to see it appear, for he was stricken with paralysis before its completion; but a printed copy was brought to his bedside and put into his hands, so that he might just feel it before he died. [illustration: fig. 3.--copernicus.] that copernicus was a giant in intellect or power--such as had lived in the past, and were destined to live in the near future--i see no reason whatever to believe. he was just a quiet, earnest, patient, and god-fearing man, a deep student, an unbiassed thinker, although with no specially brilliant or striking gifts; yet to him it was given to effect such a revolution in the whole course of man's thoughts as is difficult to parallel. you know what the outcome of his work was. it proved--he did not merely speculate, he proved--that the earth is a planet like the others, and that it revolves round the sun. yes, it can be summed up in a sentence, but what a revelation it contains. if you have never made an effort to grasp the full significance of this discovery you will not appreciate it. the doctrine is very familiar to us now, we have heard it, i suppose, since we were four years old, but can you realize it? i know it was a long time before i could. think of the solid earth, with trees and houses, cities and countries, mountains and seas--think of the vast tracts of land in asia, africa, and america--and then picture the whole mass spinning like a top, and rushing along its annual course round the sun at the rate of nineteen miles every second. were we not accustomed to it, the idea would be staggering. no wonder it was received with incredulity. but the difficulties of the conception are not only physical, they are still more felt from the speculative and theological points of view. with this last, indeed, the reconcilement cannot be considered complete even yet. theologians do not, indeed, now _deny_ the fact of the earth's subordination in the scheme of the universe, but many of them ignore it and pass it by. so soon as the church awoke to a perception of the tremendous and revolutionary import of the new doctrines, it was bound to resist them or be false to its traditions. for the whole tenor of men's thought must have been changed had they accepted it. if the earth were not the central and all-important body in the universe, if the sun and planets and stars were not attendant and subsidiary lights, but were other worlds larger and perhaps superior to ours, where was man's place in the universe? and where were the doctrines they had maintained as irrefragable? i by no means assert that the new doctrines were really utterly irreconcilable with the more essential parts of the old dogmas, if only theologians had had patience and genius enough to consider the matter calmly. i suppose that in that case they might have reached the amount of reconciliation at present attained, and not only have left scientific truth in peace to spread as it could, but might perhaps themselves have joined the band of earnest students and workers, as so many of the higher catholic clergy do at the present day. but this was too much to expect. such a revelation was not to be accepted in a day or in a century--the easiest plan was to treat it as a heresy, and try to crush it out. not in copernik's life, however, did they perceive the dangerous tendency of the doctrine--partly because it was buried in a ponderous and learned treatise not likely to be easily understood; partly, perhaps, because its propounder was himself an ecclesiastic; mainly because he was a patient and judicious man, not given to loud or intolerant assertion, but content to state his views in quiet conversation, and to let them gently spread for thirty years before he published them. and, when he did publish them, he used the happy device of dedicating his great book to the pope, and a cardinal bore the expense of printing it. thus did the roman church stand sponsor to a system of truth against which it was destined in the next century to hurl its anathemas, and to inflict on its conspicuous adherents torture, imprisonment, and death. to realize the change of thought, the utterly new view of the universe, which the copernican theory introduced, we must go back to preceding ages, and try to recall the views which had been held as probable concerning the form of the earth and the motion of the heavenly bodies. [illustration: fig. 4.--homeric cosmogony.] the earliest recorded notion of the earth is the very natural one that it is a flat area floating in an illimitable ocean. the sun was a god who drove his chariot across the heavens once a day; and anaxagoras was threatened with death and punished with banishment for teaching that the sun was only a ball of fire, and that it might perhaps be as big as the country of greece. the obvious difficulty as to how the sun got back to the east again every morning was got over--not by the conjecture that he went back in the dark, nor by the idea that there was a fresh sun every day; though, indeed, it was once believed that the moon was created once a month, and periodically cut up into stars--but by the doctrine that in the northern part of the earth was a high range of mountains, and that the sun travelled round on the surface of the sea behind these. sometimes, indeed, you find a representation of the sun being rowed round in a boat. later on it was perceived to be necessary that the sun should be able to travel beneath the earth, and so the earth was supposed to be supported on pillars or on roots, or to be a dome-shaped body floating in air--much like dean swift's island of laputa. the elephant and tortoise of the hindu earth are, no doubt, emblematic or typical, not literal. [illustration: fig. 5.--egyptian symbol of the universe. the earth a figure with leaves, the heaven a figure with stars, the principle of equilibrium and support, the boats of the rising and setting sun.] aristotle, however, taught that the earth must be a sphere, and used all the orthodox arguments of the present children's geography-books about the way you see ships at sea, and about lunar eclipses. to imagine a possible antipodes must, however, have been a tremendous difficulty in the way of this conception of a sphere, and i scarcely suppose that any one can at that time have contemplated the possibility of such upside-down regions being inhabited. i find that intelligent children invariably feel the greatest difficulty in realizing the existence of inhabitants on the opposite side of the earth. stupid children, like stupid persons in general, will of course believe anything they are told, and much good may the belief do them; but the kind of difficulties felt by intelligent and thoughtful children are most instructive, since it is quite certain that the early philosophers must have encountered and overcome those very same difficulties by their own genius. [illustration: fig. 6.--hindoo earth.] however, somehow or other the conception of a spherical earth was gradually grasped, and the heavenly bodies were perceived all to revolve round it: some moving regularly, as the stars, all fixed together into one spherical shell or firmament; some moving irregularly and apparently anomalously--these irregular bodies were therefore called planets [or wanderers]. seven of them were known, viz. moon, mercury, venus, sun, mars, jupiter, saturn, and there is little doubt that this number seven, so suggested, is the origin of the seven days of the week. the above order of the ancient planets is that of their supposed distance from the earth. not always, however, are they thus quoted by the ancients: sometimes the sun is supposed nearer than mercury or venus. it has always been known that the moon was the nearest of the heavenly bodies; and some rough notion of its distance was current. mars, jupiter, and saturn were placed in that order because that is the order of their apparent motions, and it was natural to suppose that the slowest moving bodies were the furthest off. the order of the days of the week shows what astrologers considered to be the order of the planets; on their system of each successive hour of the day being ruled over by the successive planets taken in order. the diagram (fig. 7) shows that if the sun rule the first hour of a certain day (thereby giving its name to the day) venus will rule the second hour, mercury the third, and so on; the sun will thus be found to rule the eighth, fifteenth, and twenty-second hour of that day, venus the twenty-third, and mercury the twenty-fourth hour; so the moon will rule the first hour of the next day, which will therefore be monday. on the same principle (numbering round the hours successively, with the arrows) the first hour of the next day will be found to be ruled by mars, or by the saxon deity corresponding thereto; the first hour of the day after, by mercury (_mercredi_), and so on (following the straight lines of the pattern). the order of the planets round the circle counter-clockwise, _i.e._ the direction of their proper motions, is that quoted above in the text. to explain the motion of the planets and reduce them to any sort of law was a work of tremendous difficulty. the greatest astronomer of ancient times was hipparchus, and to him the system known as the ptolemaic system is no doubt largely due. but it was delivered to the world mainly by ptolemy, and goes by his name. this was a fine piece of work, and a great advance on anything that had gone before; for although it is of course saturated with error, still it is based on a large substratum of truth. its superiority to all the previously mentioned systems is obvious. and it really did in its more developed form describe the observed motions of the planets. each planet was, in the early stages of this system, as taught, say, by eudoxus, supposed to be set in a crystal sphere, which revolved so as to carry the planet with it. the sphere had to be of crystal to account for the visibility of other planets and the stars through it. outside the seven planetary spheres, arranged one inside the other, was a still larger one in which were set the stars. this was believed to turn all the others, and was called the _primum mobile_. the whole system was supposed to produce, in its revolution, for the few privileged to hear the music of the spheres, a sound as of some magnificent harmony. [illustration: fig. 7.--order of ancient planets corresponding to the days of the week.] the enthusiastic disciples of pythagoras believed that their master was privileged to hear this noble chant; and far be it from us to doubt that the rapt and absorbing pleasure of contemplating the harmony of nature, to a man so eminently great as pythagoras, must be truly and adequately represented by some such poetic conception. [illustration: fig. 8.--ptolemaic system.] the precise kind of motion supposed to be communicated from the _primum mobile_ to the other spheres so as to produce the observed motions of the planets was modified and improved by various philosophers until it developed into the epicyclic train of hipparchus and of ptolemy. it is very instructive to observe a planet (say mars or jupiter) night after night and plot down its place with reference to the fixed stars on a celestial globe or star-map. or, instead of direct observation by alignment with known stars, it is easier to look out its right ascension and declination in _whitaker's almanac_, and plot those down. if this be done for a year or two, it will be found that the motion of the planet is by no means regular, but that though on the whole it advances it sometimes is stationary and sometimes goes back.[1] [illustration: fig. 9.--specimens of apparent paths of venus and of mars among the stars.] [illustration: fig. 10.--apparent epicyclic orbits of jupiter and saturn; the earth being supposed fixed at the centre, with the sun revolving in a small circle. a loop is made by each planet every year.] these "stations" and "retrogressions" of the planets were well known to the ancients. it was not to be supposed for a moment that the crystal spheres were subject to any irregularity, neither was uniform circular motion to be readily abandoned; so it was surmised that the main sphere carried, not the planet itself, but the centre or axis of a subordinate sphere, and that the planet was carried by this. the minor sphere could be allowed to revolve at a different uniform pace from the main sphere, and so a curve of some complexity could be obtained. a curve described in space by a point of a circle or sphere, which itself is carried along at the same time, is some kind of cycloid; if the centre of the tracing circle travels along a straight line, we get the ordinary cycloid, the curve traced in air by a nail on a coach-wheel; but if the centre of the tracing circle be carried round another circle the curve described is called an epicycloid. by such curves the planetary stations and retrogressions could be explained. a large sphere would have to revolve once for a "year" of the particular planet, carrying with it a subsidiary sphere in which the planet was fixed; this latter sphere revolving once for a "year" of the earth. the actual looped curve thus described is depicted for jupiter and saturn in the annexed diagram (fig. 10.) it was long ago perceived that real material spheres were unnecessary; such spheres indeed, though possibly transparent to light, would be impermeable to comets: any other epicyclic gearing would serve, and as a mere description of the motion it is simpler to think of a system of jointed bars, one long arm carrying a shorter arm, the two revolving at different rates, and the end of the short one carrying the planet. this does all that is needful for the first approximation to a planet's motion. in so far as the motion cannot be thus truly stated, the short arm may be supposed to carry another, and that another, and so on, so that the resultant motion of the planet is compounded of a large number of circular motions of different periods; by this device any required amount of complexity could be attained. we shall return to this at greater length in lecture iii. the main features of the motion, as shown in the diagram, required only two arms for their expression; one arm revolving with the average motion of the planet, and the other revolving with the apparent motion of the sun, and always pointing in the same direction as the single arm supposed to carry the sun. this last fact is of course because the motion to be represented does not really belong to the planet at all, but to the earth, and so all the main epicyclic motions for the superior planets were the same. as for the inferior planets (mercury and venus) they only appear to oscillate like the bob of a pendulum about the sun, and so it is very obvious that they must be really revolving round it. an ancient egyptian system perceived this truth; but the ptolemaic system imagined them to revolve round the earth like the rest, with an artificial system of epicycles to prevent their ever getting far away from the neighbourhood of the sun. it is easy now to see how the copernican system explains the main features of planetary motion, the stations and retrogressions, quite naturally and without any complexity. [illustration: fig. 11.--egyptian system.] let the outer circle represent the orbit of jupiter, and the inner circle the orbit of the earth, which is moving faster than jupiter (since jupiter takes 4332 days to make one revolution); then remember that the apparent position of jupiter is referred to the infinitely distant fixed stars and refer to fig. 12. let e_1, e_2, &c., be successive positions of the earth; j_1, j_2, &c., corresponding positions of jupiter. produce the lines e_1 j_1, e_2 j_2, &c., to an enormously greater circle outside, and it will be seen that the termination of these lines, representing apparent positions of jupiter among the stars, advances while the earth goes from e_1 to e_3; is almost stationary from somewhere about e_3 to e_4; and recedes from e_4 to e_5; so that evidently the recessions of jupiter are only apparent, and are due to the orbital motion of the earth. the apparent complications in the path of jupiter, shown in fig. 10, are seen to be caused simply by the motion of the earth, and to be thus completely and easily explained. [illustration: fig. 12.--true orbits of earth and jupiter.] the same thing for an inferior planet, say mercury, is even still more easily seen (_vide_ figure 13). the motion of mercury is direct from m'' to m''', retrograde from m''' to m'', and stationary at m'' and m'''. it appears to oscillate, taking 72·5 days for its direct swing, and 43·5 for its return swing. [illustration: fig. 13.--orbit of mercury and earth.] on this system no artificiality is required to prevent mercury's ever getting far from the sun: the radius of its orbit limits its real and apparent excursions. even if the earth were stationary, the motions of mercury and venus would not be _essentially_ modified, but the stations and retrogressions of the superior planets, mars, jupiter, &c., would wholly cease. the complexity of the old mode of regarding apparent motion may be illustrated by the case of a traveller in a railway train unaware of his own motion. it is as though trees, hedges, distant objects, were all flying past him and contorting themselves as you may see the furrows of a ploughed field do when travelling, while you yourself seem stationary amidst it all. how great a simplicity would be introduced by the hypothesis that, after all, these things might be stationary and one's self moving. [illustration: fig. 14.--copernican system as frequently represented. but the cometary orbit is a much later addition, and no attempt is made to show the relative distances of the planets.] now you are not to suppose that the system of copernicus swept away the entire doctrine of epicycles; that doctrine can hardly be said to be swept away even now. as a description of a planet's motion it is not incorrect, though it is geometrically cumbrous. if you describe the motion of a railway train by stating that every point on the rim of each wheel describes a cycloid with reference to the earth, and a circle with reference to the train, and that the motion of the train is compounded of these cycloidal and circular motions, you will not be saying what is false, only what is cumbrous. the ptolemaic system demanded large epicycles, depending on the motion of the earth, these are what copernicus overthrew; but to express the minuter details of the motion smaller epicycles remained, and grew more and more complex as observations increased in accuracy, until a greater man than either copernicus or ptolemy, viz. kepler, replaced them all by a simple ellipse. one point i must not omit from this brief notice of the work of copernicus. hipparchus had, by most sagacious interpretation of certain observations of his, discovered a remarkable phenomenon called the precession of the equinoxes. it was a discovery of the first magnitude, and such as would raise to great fame the man who should have made it in any period of the world's history, even the present. it is scarcely expressible in popular language, and without some technical terms; but i can try. the plane of the earth's orbit produced into the sky gives the apparent path of the sun throughout a year. this path is known as the ecliptic, because eclipses only happen when the moon is in it. the sun keeps to it accurately, but the planets wander somewhat above and below it (fig. 9), and the moon wanders a good deal. it is manifest, however, in order that there may be an eclipse of any kind, that a straight line must be able to be drawn through earth and moon and sun (not necessarily through their centres of course), and this is impossible unless some parts of the three bodies are in one plane, viz. the ecliptic, or something very near it. the ecliptic is a great circle of the sphere, and is usually drawn on both celestial and terrestrial globes. the earth's equator also produced into the sky, where it may still be called the equator (sometimes it is awkwardly called "the equinoctial"), gives another great circle inclined to the ecliptic and cutting it at two opposite points, labelled respectively [aries symbol] and [libra symbol], and together called "the equinoxes." the reason for the name is that when the sun is in that part of the ecliptic it is temporarily also on the equator, and hence is symmetrically situated with respect to the earth's axis of rotation, and consequently day and night are equal all over the earth. well, hipparchus found, by plotting the position of the sun for a long time,[2] that these points of intersection, or equinoxes, were not stationary from century to century, but slowly moved among the stars, moving as it were to meet the sun, so that he gets back to one of these points again 20 minutes 23-1/4 seconds before it has really completed a revolution, _i.e._ before the true year is fairly over. this slow movement forward of the goal-post is called precession--the precession of the equinoxes. (one result of it is to shorten our years by about 20 minutes each; for the shortened period has to be called a year, because it is on the position of the sun with respect to the earth's axis that our seasons depend.) copernicus perceived that, assuming the motion of the earth, a clearer account of this motion could be given. the ordinary approximate statement concerning the earth's axis is that it remains parallel to itself, _i.e._ has a fixed direction as the earth moves round the sun. but if, instead of being thus fixed, it be supposed to have a slow movement of revolution, so that it traces out a cone in the course of about 26,000 years, then, since the equator of course goes with it, the motion of its intersection with the fixed ecliptic is so far accounted for. that is to say, the precession of the equinoxes is seen to be dependent on, and caused by, a slow conical movement of the earth's axis. the prolongation of each end of the earth's axis into the sky, or the celestial north and south poles, will thus slowly trace out an approximate circle among the stars; and the course of the north pole during historic time is exhibited in the annexed diagram. it is now situated near one of the stars of the lesser bear, which we therefore call the pole star; but not always was it so, nor will it be so in the future. the position of the north pole 4000 years ago is shown in the figure; and a revolution will be completed in something like 26,000 years.[3] [illustration: fig. 15.--slow movement of the north pole in a circle among the stars. (copied from sir r. ball.)] this perception of the conical motion of the earth's axis was a beautiful generalization of copernik's, whereby a multitude of facts were grouped into a single phenomenon. of course he did not explain the motion of the axis itself. he stated the fact that it so moved, and i do not suppose it ever struck him to seek for an explanation. an explanation was given later, and that a most complete one; but the idea even of seeking for it is a brilliant and striking one: the achievement of the explanation by a single individual in the way it actually was accomplished is one of the most astounding things in the history of science; and were it not that the same individual accomplished a dozen other things, equally and some still more extraordinary, we should rank that man as one of the greatest astronomers that ever lived. as it is, he is sir isaac newton. we are to remember, then, as the life-work of copernicus, that he placed the sun in its true place as the centre of the solar system, instead of the earth; that he greatly simplified the theory of planetary motion by this step, and also by the simpler epicyclic chain which now sufficed, and which he worked out mathematically; that he exhibited the precession of the equinoxes (discovered by hipparchus) as due to a conical motion of the earth's axis; and that, by means of his simpler theory and more exact planetary tables, he reduced to some sort of order the confused chaos of the ptolemaic system, whose accumulation of complexity and of outstanding errors threatened to render astronomy impossible by the mere burden of its detail. there are many imperfections in his system, it is true; but his great merit is that he dared to look at the facts of nature with his own eyes, unhampered by the prejudice of centuries. a system venerable with age, and supported by great names, was universally believed, and had been believed for centuries. to doubt this system, and to seek after another and better one, at a time when all men's minds were governed by tradition and authority, and when to doubt was sin--this required a great mind and a high character. such a mind and such a character had this monk of frauenburg. and it is interesting to notice that the so-called religious scruples of smaller and less truly religious men did not affect copernicus; it was no dread of consequences to one form of truth that led him to delay the publication of the other form of truth specially revealed to him. in his dedication he says:-"if there be some babblers who, though ignorant of all mathematics, take upon them to judge of these things, and dare to blame and cavil at my work, because of some passage of scripture which they have wrested to their own purpose, i regard them not, and will not scruple to hold their judgment in contempt." i will conclude with the words of one of his biographers (mr. e.j.c. morton):-"copernicus cannot be said to have flooded with light the dark places of nature--in the way that one stupendous mind subsequently did--but still, as we look back through the long vista of the history of science, the dim titanic figure of the old monk seems to rear itself out of the dull flats around it, pierces with its head the mists that overshadow them, and catches the first gleam of the rising sun, "'... like some iron peak, by the creator fired with the red glow of the rushing morn.'" dates and summary of facts for lecture ii copernicus lived from 1473 to 1543, and was contemporary with paracelsus and raphael. tycho brahé from 1546 to 1601. kepler from 1571 to 1630. galileo from 1564 to 1642. gilbert from 1540 to 1603. francis bacon from 1561 to 1626. descartes from 1596 to 1650. _a sketch of tycho brahé's life and work._ tycho was a danish noble, born on his ancestral estate at knudstorp, near helsinborg, in 1546. adopted by his uncle, and sent to the university of copenhagen to study law. attracted to astronomy by the occurrence of an eclipse on its predicted day, august 21st, 1560. began to construct astronomical instruments, especially a quadrant and a sextant. observed at augsburg and wittenberg. studied alchemy, but was recalled to astronomy by the appearance of a new star. overcame his aristocratic prejudices, and delivered a course of lectures at copenhagen, at the request of the king. after this he married a peasant girl. again travelled and observed in germany. in 1576 was sent for to denmark by frederick ii., and established in the island of huen, with an endowment enabling him to devote his life to astronomy. built uraniburg, furnished it with splendid instruments, and became the founder of accurate instrumental astronomy. his theories were poor, but his observations were admirable. in 1592 frederick died, and five years later, tycho was impoverished and practically banished. after wandering till 1599, he was invited to prague by the emperor rudolf, and there received john kepler among other pupils. but the sentence of exile was too severe, and he died in 1601, aged 54 years. a man of strong character, untiring energy, and devotion to accuracy, his influence on astronomy has been immense. lecture ii tycho brahé and the earliest observatory we have seen how copernicus placed the earth in its true position in the solar system, making it merely one of a number of other worlds revolving about a central luminary. and observe that there are two phenomena to be thus accounted for and explained: first, the diurnal revolution of the heavens; second, the annual motion of the sun among the stars. the effect of the diurnal motion is conspicuous to every one, and explains the rising, southing, and setting of the whole visible firmament. the effect of the annual motion, _i.e._ of the apparent annual motion, of the sun among the stars, is less obvious, but it may be followed easily enough by observing the stars visible at any given time of evening at different seasons of the year. at midnight, for instance, the position of the sun is definite, viz. due north always, but the constellation which at that time is due south or is rising or setting varies with the time of year; an interval of one month producing just the same effect on the appearance of the constellations as an interval of two hours does (because the day contains twice as many hours as the year contains months), _e.g._ the sky looks the same at midnight on the 1st of october as it does at 10 p.m. on the 1st of november. all these simple consequences of the geocentric as opposed to the heliocentric point of view were pointed out by copernicus, in addition to his greater work of constructing improved planetary tables on the basis of his theory. but it must be admitted that he himself felt the hypothesis of the motion of the earth to be a difficulty. its acceptance is by no means such an easy and childish matter as we are apt now to regard it, and the hostility to it is not at all surprising. the human race, after having ridiculed and resisted the truth for a long time, is apt to end in accepting it so blindly and unimaginatively as to fail to recognize the real achievement of its first propounders, or the difficulties which they had to overcome. the majority of men at the present day have grown accustomed to hear the motion of the earth spoken of: their acceptance of it means nothing: the attitude of the paradoxer who denies it is more intelligent. it is not to be supposed that the idea of thus explaining some of the phenomena of the heavens, especially the daily motion of the entire firmament, by a diurnal rotation of the earth had not struck any one. it was often at this time referred to as the pythagorean theory, and it had been taught, i believe, by aristarchus. but it was new to the modern world, and it had the great weight of aristotle against it. consequently, for long after copernicus, only a few leading spirits could be found to support it, and the long-established venerable ptolemaic system continued to be taught in all universities. the main objections to the motion of the earth were such as the following:-1. the motion is unfelt and difficult to imagine. that it is unfelt is due to its uniformity, and can be explained mechanically. that it is difficult to imagine is and remains true, but a most important lesson we have to learn is that difficulty of conception is no valid argument against reality. 2. that the stars do not alter their relative positions according to the season of the year, but the constellations preserve always the same aspect precisely, even to careful measurement. this is indeed a difficulty, and a great one. in june the earth is 184 million miles away from where it was in december: how can we see precisely the same fixed stars? it is not possible, unless they are at a practically infinite distance. that is the only answer that can be given. it was the tentative answer given by copernicus. it is the correct answer. not only from every position of the earth, but from every planet of the solar system, the same constellations are visible, and the stars have the same aspect. the whole immensity of the solar system shrinks to practically a point when confronted with the distance of the stars. not, however, so entirely a speck as to resist the terrific accuracy of the present century, and their microscopic relative displacement with the season of the year has now at length been detected, and the distance of many thereby measured. 3. that, if the earth revolved round the sun, mercury and venus ought to show phases like the moon. so they ought. any globe must show phases if it live nearer the sun than we do and if we go round it, for we shall see varying amounts of its illuminated half. the only answer that copernicus could give to this was that they might be difficult to see without extra powers of sight, but he ventured to predict that the phases would be seen if ever our powers of vision should be enhanced. 4. that if the earth moved, or even revolved on its own axis, a stone or other dropped body ought to be left far behind. this difficulty is not a real one, like the two last, and it is based on an ignorance of the laws of mechanics, which had not at that time been formulated. we know now that a ball dropped from a high tower, so far from lagging, drops a minute trifle _in front_ of the foot of a perpendicular, because the top of the tower is moving a trace faster than the bottom, by reason of the diurnal rotation. but, ignoring this, a stone dropped from the lamp of a railway carriage drops in the centre of the floor, whether the carriage be moving steadily or standing still; a slant direction of fall could only be detected if the carriage were being accelerated or if the brake were applied. a body dropped from a moving carriage shares the motion of the carriage, and starts with that as its initial velocity. a ball dropped from a moving balloon does not simply drop, but starts off in whatever direction the car was moving, its motion being immediately modified by gravity, precisely in the same way as that of a thrown ball is modified. this is, indeed, the whole philosophy of throwing--to drop a ball from a moving carriage. the carriage is the hand, and, to throw far, a run is taken and the body is jerked forward; the arm is also moved as rapidly as possible on the shoulder as pivot. the fore-arm can be moved still faster, and the wrist-joint gives yet another motion: the art of throwing is to bring all these to bear at the same instant, and then just as they have all attained their maximum velocity to let the ball go. it starts off with the initial velocity thus imparted, and is abandoned to gravity. if the vehicle were able to continue its motion steadily, as a balloon does, the ball when let go from it would appear to the occupant simply to drop; and it would strike the ground at a spot vertically under the moving vehicle, though by no means vertically below the place where it started. the resistance of the air makes observations of this kind inaccurate, except when performed inside a carriage so that the air shares in the motion. otherwise a person could toss and catch a ball out of a train window just as well as if he were stationary; though to a spectator outside he would seem to be using great skill to throw the ball in the parabola adapted to bring it back to his hand. the same circumstance enhances the apparent difficulty of the circus rider's jumping feats. all he has to do is to jump up and down on the horse; the forward motion which carries him through hoops belongs to him by virtue of the motion of the horse, without effort on his part. thus, then, it happens that a stone dropped sixteen feet on the earth appears to fall straight down, although its real path in space is a very flat trajectory of nineteen miles base and sixteen feet height; nineteen miles being the distance traversed by the earth every second in the course of its annual journey round the sun. no wonder that it was thought that bodies must be left behind if the earth was subject to such terrific speed as this. all that copernicus could suggest on this head was that perhaps the atmosphere might help to carry things forward, and enable them to keep pace with the earth. there were thus several outstanding physical difficulties in the way of the acceptance of the copernican theory, besides the biblical difficulty. it was quite natural that the idea of the earth's motion should be repugnant, and take a long time to sink into the minds of men; and as scientific progress was vastly slower then than it is now, we find not only all priests but even some astronomers one hundred years afterwards still imagining the earth to be at rest. and among them was a very eminent one, tycho brahé. it is interesting to note, moreover, that the argument about the motion of the earth being contrary to scripture appealed not only to ecclesiastics in those days, but to scientific men also; and tycho brahé, being a man of great piety, and highly superstitious also, was so much influenced by it, that he endeavoured to devise some scheme by which the chief practical advantages of the copernican system could be retained, and yet the earth be kept still at the centre of the whole. this was done by making all the celestial sphere, with stars and everything, rotate round the earth once a day, as in the ptolemaic scheme; and then besides this making all the planets revolve round the sun, and this to revolve round the earth. such is the tychonic system. so far as _relative_ motion is concerned it comes to the same thing; just as when you drop a book you may say either that the earth rises to meet the book, or that the book falls to meet the earth. or when a fly buzzes round your head, you may say that you are revolving round the fly. but the absurdity of making the whole gigantic system of sun and planets and stars revolve round our insignificant earth was too great to be swallowed by other astronomers after they had once had a taste of the copernican theory; and accordingly the tychonic system died a speedy and an easy death at the same time as its inventor. wherein then lay the magnitude of the man?--not in his theories, which were puerile, but in his observations, which were magnificent. he was the first observational astronomer, the founder of the splendid system of practical astronomy which has culminated in the present greenwich observatory. [illustration: fig. 16.--tychonic system showing the sun with all the planets revolving round the earth.] up to tycho the only astronomical measurements had been of the rudest kind. copernicus even improved upon what had gone before, with measuring rules made with his own hands. ptolemy's observations could never be trusted to half a degree. tycho introduced accuracy before undreamed of, and though his measurements, reckoned by modern ideas, are of course almost ludicrously rough (remember no such thing as a telescope or microscope was then dreamed of), yet, estimated by the era in which they were made, they are marvels of accuracy, and not a single mistake due to carelessness has ever been detected in them. in fact they may be depended on almost to minutes of arc, _i.e._ to sixtieths of a degree. for certain purposes connected with the proper motion of stars they are still appealed to, and they served as the certain and trustworthy data for succeeding generations of theorists to work upon. it was long, indeed, after tycho's death before observations approaching in accuracy to his were again made. in every sense, therefore, he was a pioneer: let us proceed to trace his history. born the eldest son of a noble family--"as noble and ignorant as sixteen undisputed quarterings could make them," as one of his biographers says--in a period when, even more than at present, killing and hunting were the only natural aristocratic pursuits, when all study was regarded as something only fit for monks, and when science was looked at askance as something unsavoury, useless, and semi-diabolic, there was little in his introduction to the world urging him in the direction where his genius lay. of course he was destined for a soldier; but fortunately his uncle, george brahé, a more educated man than his father, having no son of his own, was anxious to adopt him, and though not permitted to do so for a time, succeeded in getting his way on the birth of a second son, steno--who, by the way, ultimately became privy councillor to the king of denmark. tycho's uncle gave him what he would never have got at home--a good education; and ultimately put him to study law. at the age of thirteen he entered the university of copenhagen, and while there occurred the determining influence of his life. an eclipse of the sun in those days was not regarded with the cold-blooded inquisitiveness or matter-of-fact apathy, according as there is or is not anything to be learnt from it, with which such an event is now regarded. every occurrence in the heavens was then believed to carry with it the destiny of nations and the fate of individuals, and accordingly was of surpassing interest. ever since the time of hipparchus it had been possible for some capable man here and there to predict the occurrence of eclipses pretty closely. the thing is not difficult. the prediction was not, indeed, to the minute and second, as it is now; but the day could usually be hit upon pretty accurately some time ahead, much as we now manage to hit upon the return of a comet--barring accidents; and the hour could be predicted as the event approached. well, the boy tycho, among others, watched for this eclipse on august 21st, 1560; and when it appeared at its appointed time, every instinct for the marvellous, dormant in his strong nature, awoke to strenuous life, and he determined to understand for himself a science permitting such wonderful possibilities of prediction. he was sent to leipzig with a tutor to go on with his study of law, but he seems to have done as little law as possible: he spent all his money on books and instruments, and sat up half the night studying and watching the stars. in 1563 he observed a conjunction of jupiter and saturn, the precursor, and _cause_ as he thought it, of the great plague. he found that the old planetary tables were as much as a month in error in fixing this event, and even the copernican tables were several days out; so he formed the resolve to devote his life to improving astronomical tables. this resolve he executed with a vengeance. his first instrument was a jointed ruler with sights for fixing the position of planets with respect to the stars, and observing their stations and retrogressions. by thus measuring the angles between a planet and two fixed stars, its position can be plotted down on a celestial map or globe. [illustration: fig. 17.--portrait of tycho.] in 1565 his uncle george died, and made tycho his heir. he returned to denmark, but met with nothing but ridicule and contempt for his absurd drivelling away of time over useless pursuits. so he went back to germany--first to wittenberg, thence, driven by the plague, to rostock. here his fiery nature led him into an absurd though somewhat dangerous adventure. a quarrel at some feast, on a mathematical point, with a countryman, manderupius, led to the fixing of a duel, and it was fought with swords at 7 p.m. at the end of december, when, if there was any light at all, it must have been of a flickering and unsatisfactory nature. the result of this insane performance was that tycho got his nose cut clean off. he managed however to construct an artificial one, some say of gold and silver, some say of putty and brass; but whatever it was made of there is no doubt that he wore it for the rest of his life, and it is a most famous feature. it excited generally far more interest than his astronomical researches. it is said, moreover, to have very fairly resembled the original, but whether this remark was made by a friend or by an enemy i cannot say. one account says that he used to carry about with him a box of cement to apply whenever his nose came off, which it periodically did. about this time he visited augsburg, met with some kindred and enlightened spirits in that town, and with much enthusiasm and spirit constructed a great quadrant. these early instruments were tremendous affairs. a great number of workmen were employed upon this quadrant, and it took twenty men to carry it to its place and erect it. it stood in the open air for five years, and then was destroyed by a storm. with it he made many observations. [illustration: fig. 18.--early out-door quadrant of tycho; for observing altitudes by help of the sights _d_, _l_ and the plumb line.] on his return to denmark in 1571, his fame preceded him, and he was much better received; and in order to increase his power of constructing instruments he took up the study of alchemy, and like the rest of the persuasion tried to make gold. the precious metals were by many old philosophers considered to be related in some way to the heavenly bodies: silver to the moon, for instance--as we still see by the name lunar caustic applied to nitrate of silver; gold to the sun, copper to mars, lead to saturn. hence astronomy and alchemy often went together. tycho all his life combined a little alchemy with his astronomical labours, and he constructed a wonderful patent medicine to cure all disorders, which had as wide a circulation in europe in its time as holloway's pills; he gives a tremendous receipt for it, with liquid gold and all manner of ingredients in it; among them, however, occurs a little antimony--a well-known sudorific--and to this, no doubt, whatever efficacy the medicine possessed was due. so he might have gone on wasting his time, were it not that in november, 1572, a new star made its appearance, as they have done occasionally before and since. on the average one may say that about every fifty years a new star of fair magnitude makes its temporary appearance. they are now known to be the result of some catastrophe or collision, whereby immense masses of incandescent gas are produced. this one seen by tycho became as bright as jupiter, and then died away in about a year and a half. tycho observed all its changes, and endeavoured to measure its distance from the earth, with the result that it was proved to belong to the region of the fixed stars, at an immeasurable distance, and was not some nearer and more trivial phenomenon. he was asked by the university of copenhagen to give a course of lectures on astronomy; but this was a step he felt some aristocratic aversion to, until a little friendly pressure was brought to bear upon him by a request from the king, and delivered they were. he now seems to have finally thrown off his aristocratic prejudices, and to have indulged himself in treading on the corns of nearly all the high and mighty people he came into contact with. in short, he became what we might now call a violent radical; but he was a good-hearted man, nevertheless, and many are the tales told of his visits to sick peasants, of his consulting the stars as to their fate--all in perfect good faith--and of the medicines which he concocted and prescribed for them. the daughter of one of these peasants he married, and very happy the marriage seems to have been. [illustration: fig. 19.--map of denmark, showing the island of huen. _walker & boutallse._] now comes the crowning episode in tycho's life. frederick ii., realizing how eminent a man they had among them, and how much he could do if only he had the means--for we must understand that tycho, though of good family and well off, was by no means what we would call a wealthy man--frederick ii. made him a splendid and enlightened offer. the offer was this: that if tycho would agree to settle down and make his astronomical observations in denmark, he should have an estate in norway settled upon him, a pension of £400 a year for life, a site for a large observatory, and £20,000 to build it with. [illustration: fig. 20.--uraniburg.] [illustration: fig. 21.--astrolabe. an old instrument with sights for marking the positions of the celestial bodies roughly. a sort of skeleton celestial globe.] [illustration: sextans astronomicvs trigonicvs pro distantiis rimandis. fig. 22.--tycho's large sextant; for measuring the angular distance between two bodies by direct sighting.] well, if ever money was well spent, this was. by its means denmark before long headed the nations of europe in the matter of science--a thing it has not done before or since. the site granted was the island of huen, between copenhagen and elsinore; and here the most magnificent observatory ever built was raised, and called uraniburg--the castle of the heavens. it was built on a hill in the centre of the island, and included gardens, printing shops, laboratory, dwelling-houses, and four observatories--all furnished with the most splendid instruments that tycho could devise, and that could then be constructed. it was decorated with pictures and sculptures of eminent men, and altogether was a most gorgeous place. £20,000 no doubt went far in those days, but the original grant was supplemented by tycho himself, who is said to have spent another equal sum out of his own pocket on the place. [illustration: qvadrans maximvs chalibeus quadrato inclusus, et horizonti azimuthali chalybeo insistens. fig. 23.--the quadrant in uraniburg; or altitude and azimuth instrument.] for twenty years this great temple of science was continually worked in by him, and he soon became the foremost scientific man in europe. philosophers, statesmen, and occasionally kings, came to visit the great astronomer, and to inspect his curiosities. [illustration: qvadrans mvralis sive tichonicus. fig. 24.--tycho's form of transit circle. the method of utilising the extremely uniform rotation of the earth by watching the planets and stars as they cross the meridian, and recording their times of transit; observing also at the same time their meridian altitudes (see observer _f_), was the invention of tycho, and constitutes his greatest achievement. his method is followed to this day in all observatories.] [illustration: fig. 25.--a modern transit circle, showing essentially the same parts as in tycho's instrument, viz. the observer watching the transit, the clock, the recorder of the observation, and the graduated circle; the latter to be read by a second observer.] and very wholesome for some of these great personages must have been the treatment they met with. for tycho was no respecter of persons. his humbly-born wife sat at the head of the table, whoever was there; and he would snub and contradict a chancellor just as soon as he would a serf. whatever form his pride may have taken when a youth, in his maturity it impelled him to ignore differences of rank not substantially justified, and he seemed to take a delight in exposing the ignorance of shallow titled persons, to whom contradiction and exposure were most unusual experiences. for sick peasants he would take no end of trouble, and went about doctoring them for nothing, till he set all the professional doctors against him; so that when his day of misfortune came, as come it did, their influence was not wanting to help to ruin one who spoilt their practice, and whom they derided as a quack. but some of the great ignorant folk who came to visit his temple of science, and to inspect its curiosities, felt themselves insulted--not always without reason. he kept a tame maniac in the house, named lep, and he used to regard the sayings of this personage as oracular, presaging future events, and far better worth listening to than ordinary conversation. consequently he used to have him at his banquets and feed him himself; and whenever lep opened his mouth to speak, every one else was peremptorily ordered to hold his tongue, so that lep's words might be written down. in fact it was something like an exaggerated edition of betsy trotwood and mr. dick. "it must have been an odd dinner party" (says prof. stuart), "with this strange, wild, terribly clever man, with his red hair and brazen nose, sometimes flashing with wit and knowledge, sometimes making the whole company, princes and servants alike, hold their peace and listen humbly to the ravings of a poor imbecile." to people he despised he did not show his serious instruments. he had other attractions, in the shape of a lot of toy machinery, little windmills, and queer doors, and golden globes, and all manner of ingenious tricks and automata, many of which he had made himself, and these he used to show them instead; and no doubt they were well enough pleased with them. those of the visitors, however, who really cared to see and understand his instruments, went away enchanted with his genius and hospitality. i may, perhaps, be producing an unfair impression of imperiousness and insolence. tycho was fiery, no doubt, but i think we should wrong him if we considered him insolent. most of the nobles of his day were haughty persons, accustomed to deal with serfs, and very likely to sneer at and trample on any meek man of science whom they could easily despise. so tycho was not meek; he stood up for the honour of his science, and paid them back in their own coin, with perhaps a little interest. that this behaviour was not worldly-wise is true enough, but i know of no commandment enjoining us to be worldly-wise. if we knew more about his so-called imbecile _protégé_ we should probably find some reason for the interest which tycho took in him. whether he was what is now called a "clairvoyant" or not, tycho evidently regarded his utterances as oracular, and of course when one is receiving what may be a revelation from heaven it is natural to suppress ordinary conversation. among the noble visitors whom he received and entertained, it is interesting to notice james i. of england, who spent eight days at uraniburg on the occasion of his marriage with anne of denmark in 1590, and seems to have been deeply impressed by his visit. among other gifts, james presented tycho with a dog (depicted in fig. 24), and this same animal was subsequently the cause of trouble. for it seems that one day the chancellor of denmark, walchendorf, brutally kicked the poor beast; and tycho, who was very fond of animals, gave him a piece of his mind in no measured language. walchendorf went home determined to ruin him. king frederick, however, remained his true friend, doubtless partly influenced thereto by his queen sophia, an enlightened woman who paid many visits to uraniburg, and knew tycho well. but unfortunately frederick died; and his son, a mere boy, came to the throne. now was the time for the people whom tycho had offended, for those who were jealous of his great fame and importance, as well as for those who cast longing eyes on his estate and endowments. the boy-king, too, unfortunately paid a visit to tycho, and, venturing upon a decided opinion on some recondite subject, received a quiet setting down which he ill relished. letters written by tycho about this time are full of foreboding. he greatly dreads having to leave uraniburg, with which his whole life has for twenty years been bound up. he tries to comfort himself with the thought that, wherever he is sent, he will have the same heavens and the same stars over his head. gradually his norwegian estate and his pension were taken away, and in five years poverty compelled him to abandon his magnificent temple, and to take a small house in copenhagen. not content with this, walchendorf got a royal commission appointed to inquire into the value of his astronomical labours. this sapient body reported that his work was not only useless, but noxious; and soon after he was attacked by the populace in the public street. nothing was left for him now but to leave the country, and he went into germany, leaving his wife and instruments to follow him whenever he could find a home for them. his wanderings in this dark time--some two years--are not quite clear; but at last the enlightened emperor of bohemia, rudolph ii., invited him to settle in prague. thither he repaired, a castle was given him as an observatory, a house in the city, and 3000 crowns a year for life. so his instruments were set up once more, students flocked to hear him and to receive work at his hands--among them a poor youth, john kepler, to whom he was very kind, and who became, as you know, a still greater man than his master. but the spirit of tycho was broken, and though some good work was done at prague--more observations made, and the rudolphine tables begun--yet the hand of death was upon him. a painful disease seized him, attended with sleeplessness and temporary delirium, during the paroxysms of which he frequently exclaimed, _ne frustra vixisse videar_. ("oh that it may not appear that i have lived in vain!") quietly, however, at last, and surrounded by his friends and relatives, this fierce, passionate soul passed away, on the 24th of october, 1601. his beloved instruments, which were almost a part of himself, were stored by rudolph in a museum with scrupulous care, until the taking of prague by the elector palatine's troops. in this disturbed time they got smashed, dispersed, and converted to other purposes. one thing only was saved--the great brass globe, which some thirty years after was recognized by a later king of denmark as having belonged to tycho, and deposited in the library of the academy of sciences at copenhagen, where i believe it is to this day. the island of huen was overrun by the danish nobility, and nothing now remains of uraniburg but a mound of earth and two pits. as to the real work of tycho, that has become immortal enough,--chiefly through the labours of his friend and scholar whose life we shall consider in the next lecture. summary of facts for lecture iii _life and work of kepler._ kepler was born in december, 1571, at weil in würtemberg. father an officer in the duke's army, mother something of a virago, both very poor. kepler was utilized as a tavern pot-boy, but ultimately sent to a charity school, and thence to the university of tübingen. health extremely delicate; he was liable to violent attacks all his life. studied mathematics, and accepted an astronomical lectureship at graz as the first post which offered. endeavoured to discover some connection between the number of the planets, their times of revolution, and their distances from the sun. ultimately hit upon his fanciful regular-solid hypothesis, and published his first book in 1597. in 1599 was invited by tycho to prague, and there appointed imperial mathematician, at a handsome but seldom paid salary. observed the new star of 1604. endeavoured to find the law of refraction of light from vitellio's measurements, but failed. analyzed tycho's observations to find the true law of motion of mars. after incredible labour, through innumerable wrong guesses, and six years of almost incessant calculation, he at length emerged in his two "laws"--discoveries which swept away all epicycles, deferents, equants, and other remnants of the greek system, and ushered in the dawn of modern astronomy. law i. _planets move in ellipses, with the sun in one focus._ law ii. _the radius vector (or line joining sun and planet) sweeps out equal areas in equal times._ published his second book containing these laws in 1609. death of rudolph in 1612, and subsequent increased misery and misfortune of kepler. ultimately discovered the connection between the times and distances of the planets for which he had been groping all his mature life, and announced it in 1618:-law iii. _the square of the time of revolution (or year) of each planet is proportional to the cube of its mean distance from the sun._ the book in which this law was published ("on celestial harmonies") was dedicated to james of england. in 1620 had to intervene to protect his mother from being tortured for witchcraft. accepted a professorship at linz. published the rudolphine tables in 1627, embodying tycho's observations and his own theory. made a last effort to overcome his poverty by getting the arrears of his salary paid at prague, but was unsuccessful, and, contracting brain fever on the journey, died in november, 1630, aged 59. a man of keen imagination, indomitable perseverance, and uncompromising love of truth, kepler overcame ill-health, poverty, and misfortune, and placed himself in the very highest rank of scientific men. his laws, so extraordinarily discovered, introduced order and simplicity into what else would have been a chaos of detailed observations; and they served as a secure basis for the splendid erection made on them by newton. _seven planets of the ptolemaic system--_ moon, mercury, venus, sun, mars, jupiter, saturn. _six planets of the copernican system--_ mercury, venus, earth, mars, jupiter, saturn. _the five regular solids, in appropriate order--_ octahedron, icosahedron, dodecahedron, tetrahedron, cube. _table illustrating kepler's third law._ +---------+---------------+-----------+---------------+----------------+ | | mean distance | length | cube of the | square of the | | planet. | from sun. | of year. | distance. | time. | | | d | t | d^3 | t^2 | +---------+---------------+-----------+---------------+----------------+ | mercury | ·3871 | ·24084 | ·05801 | ·05801 | | venus | ·7233 | ·61519 | ·37845 | ·37846 | | earth | 1·0000 | 1·0000 | 1·0000 | 1·0000 | | mars | 1·5237 | 1·8808 | 3·5375 | 3·5375 | | jupiter | 5·2028 | 11·862 | 140·83 | 140·70 | | saturn | 9·5388 | 29·457 | 867·92 | 867·70 | +---------+---------------+-----------+---------------+----------------+ the length of the earth's year is 365·256 days; its mean distance from the sun, taken above as unity, is 92,000,000 miles. lecture iii kepler and the laws of planetary motion it is difficult to imagine a stronger contrast between two men engaged in the same branch of science than exists between tycho brahé, the subject of last lecture, and kepler, our subject on the present occasion. the one, rich, noble, vigorous, passionate, strong in mechanical ingenuity and experimental skill, but not above the average in theoretical and mathematical power. the other, poor, sickly, devoid of experimental gifts, and unfitted by nature for accurate observation, but strong almost beyond competition in speculative subtlety and innate mathematical perception. the one is the complement of the other; and from the fact of their following each other so closely arose the most surprising benefits to science. the outward life of kepler is to a large extent a mere record of poverty and misfortune. i shall only sketch in its broad features, so that we may have more time to attend to his work. he was born (so his biographer assures us) in longitude 29° 7', latitude 48° 54', on the 21st of december, 1571. his parents seem to have been of fair condition, but by reason, it is said, of his becoming surety for a friend, the father lost all his slender income, and was reduced to keeping a tavern. young john kepler was thereupon taken from school, and employed as pot-boy between the ages of nine and twelve. he was a sickly lad, subject to violent illnesses from the cradle, so that his life was frequently despaired of. ultimately he was sent to a monastic school and thence to the university of tübingen, where he graduated second on the list. meanwhile home affairs had gone to rack and ruin. his father abandoned the home, and later died abroad. the mother quarrelled with all her relations, including her son john; who was therefore glad to get away as soon as possible. all his connection with astronomy up to this time had been the hearing the copernican theory expounded in university lectures, and defending it in a college debating society. an astronomical lectureship at graz happening to offer itself, he was urged to take it, and agreed to do so, though stipulating that it should not debar him from some more brilliant profession when there was a chance. for astronomy in those days seems to have ranked as a minor science, like mineralogy or meteorology now. it had little of the special dignity with which the labours of kepler himself were destined so greatly to aid in endowing it. well, he speedily became a thorough copernican, and as he had a most singularly restless and inquisitive mind, full of appreciation of everything relating to number and magnitude--was a born speculator and thinker just as mozart was a born musician, or bidder a born calculator--he was agitated by questions such as these: why are there exactly six planets? is there any connection between their orbital distances, or between their orbits and the times of describing them? these things tormented him, and he thought about them day and night. it is characteristic of the spirit of the times--this questioning why there should be six planets. nowadays, we should simply record the fact and look out for a seventh. then, some occult property of the number six was groped for, such as that it was equal to 1 + 2 + 3 and likewise equal to 1 × 2 × 3, and so on. many fine reasons had been given for the seven planets of the ptolemaic system (see, for instance, p. 106), but for the six planets of the copernican system the reasons were not so cogent. again, with respect to their successive distances from the sun, some law would seem to regulate their distance, but it was not known. (parenthetically i may remark that it is not known even now: a crude empirical statement known as bode's law--see page 294--is all that has been discovered.) once more, the further the planet the slower it moved; there seemed to be some law connecting speed and distance. this also kepler made continual attempts to discover. [illustration: fig. 26.--orbits of some of the planets drawn to scale: showing the gap between mars and jupiter.] one of his ideas concerning the law of the successive distances was based on the inscription of a triangle in a circle. if you inscribe in a circle a large number of equilateral triangles, they envelop another circle bearing a definite ratio to the first: these might do for the orbits of two planets (see fig. 27). then try inscribing and circumscribing squares, hexagons, and other figures, and see if the circles thus defined would correspond to the several planetary orbits. but they would not give any satisfactory result. brooding over this disappointment, the idea of trying solid figures suddenly strikes him. "what have plane figures to do with the celestial orbits?" he cries out; "inscribe the regular solids." and then--brilliant idea--he remembers that there are but five. euclid had shown that there could be only five regular solids.[4] the number evidently corresponds to the gaps between the six planets. the reason of there being only six seems to be attained. this coincidence assures him he is on the right track, and with great enthusiasm and hope he "represents the earth's orbit by a sphere as the norm and measure of all"; round it he circumscribes a dodecahedron, and puts another sphere round that, which is approximately the orbit of mars; round that, again, a tetrahedron, the corners of which mark the sphere of the orbit of jupiter; round that sphere, again, he places a cube, which roughly gives the orbit of saturn. [illustration: fig. 27.--many-sided polygon or approximate circle enveloped by straight lines, as for instance by a number of equilateral triangles.] on the other hand, he inscribes in the sphere of the earth's orbit an icosahedron; and inside the sphere determined by that, an octahedron; which figures he takes to inclose the spheres of venus and of mercury respectively. the imagined discovery is purely fictitious and accidental. first of all, eight planets are now known; and secondly, their real distances agree only very approximately with kepler's hypothesis. [illustration: fig. 28.--frameworks with inscribed and circumscribed spheres, representing the five regular solids distributed as kepler supposed them to be among the planetary orbits. (see "summary" at beginning of this lecture, p. 57.)] nevertheless, the idea gave him great delight. he says:--"the intense pleasure i have received from this discovery can never be told in words. i regretted no more the time wasted; i tired of no labour; i shunned no toil of reckoning, days and nights spent in calculation, until i could see whether my hypothesis would agree with the orbits of copernicus, or whether my joy was to vanish into air." he then went on to speculate as to the cause of the planets' motion. the old idea was that they were carried round by angels or celestial intelligences. kepler tried to establish some propelling force emanating from the sun, like the spokes of a windmill. this first book of his brought him into notice, and served as an introduction to tycho and to galileo. tycho brahé was at this time at prague under the patronage of the emperor rudolph; and as he was known to have by far the best planetary observations of any man living, kepler wrote to him to know if he might come and examine them so as to perfect his theory. tycho immediately replied, "come, not as a stranger, but as a very welcome friend; come and share in my observations with such instruments as i have with me, and as a dearly beloved associate." after this visit, tycho wrote again, offering him the post of mathematical assistant, which after hesitation was accepted. part of the hesitation kepler expresses by saying that "for observations his sight was dull, and for mechanical operations his hand was awkward. he suffered much from weak eyes, and dare not expose himself to night air." in all this he was, of course, the antipodes of tycho, but in mathematical skill he was greatly his superior. on his way to prague he was seized with one of his periodical illnesses, and all his means were exhausted by the time he could set forward again, so that he had to apply for help to tycho. it is clear, indeed, that for some time now he subsisted entirely on the bounty of tycho, and he expresses himself most deeply grateful for all the kindness he received from that noble and distinguished man, the head of the scientific world at that date. to illustrate tycho's kindness and generosity, i must read you a letter written to him by kepler. it seems that kepler, on one of his absences from prague, driven half mad with poverty and trouble, fell foul of tycho, whom he thought to be behaving badly in money matters to him and his family, and wrote him a violent letter full of reproaches and insults. tycho's secretary replied quietly enough, pointing out the groundlessness and ingratitude of the accusation. kepler repents instantly, and replies:- "most noble tycho," (these are the words of his letter), "how shall i enumerate or rightly estimate your benefits conferred on me? for two months you have liberally and gratuitously maintained me, and my whole family; you have provided for all my wishes; you have done me every possible kindness; you have communicated to me everything you hold most dear; no one, by word or deed, has intentionally injured me in anything; in short, not to your children, your wife, or yourself have you shown more indulgence than to me. this being so, as i am anxious to put on record, i cannot reflect without consternation that i should have been so given up by god to my own intemperance as to shut my eyes on all these benefits; that, instead of modest and respectful gratitude, i should indulge for three weeks in continual moroseness towards all your family, in headlong passion and the utmost insolence towards yourself, who possess so many claims on my veneration, from your noble family, your extraordinary learning, and distinguished reputation. whatever i have said or written against the person, the fame, the honour, and the learning of your excellency; or whatever, in any other way, i have injuriously spoken or written (if they admit no other more favourable interpretation), as, to my grief, i have spoken and written many things, and more than i can remember; all and everything i recant, and freely and honestly declare and profess to be groundless, false, and incapable of proof." tycho accepted the apology thus heartily rendered, and the temporary breach was permanently healed. in 1601, kepler was appointed "imperial mathematician," to assist tycho in his calculations. the emperor rudolph did a good piece of work in thus maintaining these two eminent men, but it is quite clear that it was as astrologers that he valued them; and all he cared for in the planetary motions was limited to their supposed effect on his own and his kingdom's destiny. he seems to have been politically a weak and superstitious prince, who was letting his kingdom get into hopeless confusion, and entangling himself in all manner of political complications. while bohemia suffered, however, the world has benefited at his hands; and the tables upon which tycho was now engaged are well called the rudolphine tables. these tables of planetary motion tycho had always regarded as the main work of his life; but he died before they were finished, and on his death-bed he intrusted the completion of them to kepler, who loyally undertook their charge. the imperial funds were by this time, however, so taxed by wars and other difficulties that the tables could only be proceeded with very slowly, a staff of calculators being out of the question. in fact, kepler could not get even his own salary paid: he got orders, and promises, and drafts on estates for it; but when the time came for them to be honoured they were worthless, and he had no power to enforce his claims. so everything but brooding had to be abandoned as too expensive, and he proceeded to study optics. he gave a very accurate explanation of the action of the human eye, and made many hypotheses, some of them shrewd and close to the mark, concerning the law of refraction of light in dense media: but though several minor points of interest turned up, nothing of the first magnitude came out of this long research. the true law of refraction was discovered some years after by a dutch professor, willebrod snell. we must now devote a little time to the main work of kepler's life. all the time he had been at prague he had been making a severe study of the motion of the planet mars, analyzing minutely tycho's books of observations, in order to find out, if possible, the true theory of his motion. aristotle had taught that circular motion was the only perfect and natural motion, and that the heavenly bodies therefore necessarily moved in circles. so firmly had this idea become rooted in men's minds, that no one ever seems to have contemplated the possibility of its being false or meaningless. when hipparchus and others found that, as a matter of fact, the planets did _not_ revolve in simple circles, they did not try other curves, as we should at once do now, but they tried combinations of circles, as we saw in lecture i. the small circle carried by a bigger one was called an epicycle. the carrying circle was called the deferent. if for any reason the earth had to be placed out of the centre, the main planetary orbit was called an excentric, and so on. but although the planetary paths might be roughly represented by a combination of circles, their speeds could not, on the hypothesis of uniform motion in each circle round the earth as a fixed body. hence was introduced the idea of an equant, _i.e._ an arbitrary point, not the earth, about which the speed might be uniform. copernicus, by making the sun the centre, had been able to simplify a good deal of this, and to abolish the equant. but now that kepler had the accurate observations of tycho to refer to, he found immense difficulty in obtaining the true positions of the planets for long together on any such theory. he specially attacked the motion of the planet mars, because that was sufficiently rapid in its changes for a considerable collection of data to have accumulated with respect to it. he tried all manner of circular orbits for the earth and for mars, placing them in all sorts of aspects with respect to the sun. the problem to be solved was to choose such an orbit and such a law of speed, for both the earth and mars, that a line joining them, produced out to the stars, should always mark correctly the apparent position of mars as seen from the earth. he had to arrange the size of the orbits that suited best, then the positions of their centres, both being supposed excentric with respect to the sun; but he could not get any such arrangement to work with uniform motion about the sun. so he reintroduced the equant, and thus had another variable at his disposal--in fact, two, for he had an equant for the earth and another for mars, getting a pattern of the kind suggested in fig. 29. the equants might divide the line in any arbitrary ratio. all sorts of combinations had to be tried, the relative positions of the earth and mars to be worked out for each, and compared with tycho's recorded observations. it was easy to get them to agree for a short time, but sooner or later a discrepancy showed itself. [illustration: fig. 29.--_s_ represents the sun; _ec_, the centre of the earth's orbit, to be placed as best suited; _mc_, the same for mars; _ee_, the earth's equant, or point about which the earth uniformly revolved (_i.e._ the point determining the law of speed about the sun), likewise to be placed anywhere, but supposed to be in the line joining _s_ to _ec_; _me_, the same thing for mars; with _?me_ for an alternative hypothesis that perhaps mars' equant was on line joining _ec_ with _mc_.] i need not say that all these attempts and gropings, thus briefly summarized, entailed enormous labour, and required not only great pertinacity, but a most singularly constituted mind, that could thus continue groping in the dark without a possible ray of theory to illuminate its search. grope he did, however, with unexampled diligence. at length he hit upon a point that seemed nearly right. he thought he had found the truth; but no, before long the position of the planet, as calculated, and as recorded by tycho, differed by eight minutes of arc, or about one-eighth of a degree. could the observation be wrong by this small amount? no, he had known tycho, and knew that he was never wrong eight minutes in an observation. so he set out the whole weary way again, and said that with those eight minutes he would yet find out the law of the universe. he proceeded to see if by making the planet librate, or the plane of its orbit tilt up and down, anything could be done. he was rewarded by finding that at any rate the plane of the orbit did not tilt up and down: it was fixed, and this was a simplification on copernicus's theory. it is not an absolute fixture, but the changes are very small (see laplace, page 266). [illustration: fig. 30.--excentric circle supposed to be divided into equal areas. the sun, _s_, being placed at a selected point, it was possible to represent the varying speed of a planet by saying that it moved from _a_ to _b_, from _b_ to _c_, and so on, in equal times.] at last he thought of giving up the idea of _uniform_ circular motion, and of trying _varying_ circular motion, say inversely as its distance from the sun. to simplify calculation, he divided the orbit into triangles, and tried if making the triangles equal would do. a great piece of luck, they did beautifully: the rate of description of areas (not arcs) is uniform. over this discovery he greatly rejoices. he feels as though he had been carrying on a war against the planet and had triumphed; but his gratulation was premature. before long fresh little errors appeared, and grew in importance. thus he announces it himself:-"while thus triumphing over mars, and preparing for him, as for one already vanquished, tabular prisons and equated excentric fetters, it is buzzed here and there that the victory is vain, and that the war is raging anew as violently as before. for the enemy left at home a despised captive has burst all the chains of the equations, and broken forth from the prisons of the tables." still, a part of the truth had been gained, and was not to be abandoned any more. the law of speed was fixed: that which is now known as his second law. but what about the shape of the orbit--was it after all possible that aristotle, and every philosopher since aristotle, had been wrong? that circular motion was not the perfect and natural motion, but that planets might move in some other closed curve? suppose he tried an oval. well, there are a great variety of ovals, and several were tried: with the result that they could be made to answer better than a circle, but still were not right. now, however, the geometrical and mathematical difficulties of calculation, which before had been tedious and oppressive, threatened to become overwhelming; and it is with a rising sense of despondency that kepler sees his six years' unremitting labour leading deeper and deeper into complication. one most disheartening circumstance appeared, viz. that when he made the circuit oval his law of equable description of areas broke down. that seemed to require the circular orbit, and yet no circular orbit was quite accurate. while thinking and pondering for weeks and months over this new dilemma and complication of difficulties, till his brain reeled, an accidental ray of light broke upon him in a way not now intelligible, or barely intelligible. half the extreme breadth intercepted between the circle and oval was 429/100,000 of the radius, and he remembered that the "optical inequality" of mars was also about 429/100,000. this coincidence, in his own words, woke him out of sleep; and for some reason or other impelled him instantly to try making the planet oscillate in the diameter of its epicycle instead of revolve round it--a singular idea, but copernicus had had a similar one to explain the motions of mercury. [illustration: fig. 31.--mode of drawing an ellipse. the two pins _f_ are the foci.] away he started through his calculations again. a long course of work night and day was rewarded by finding that he was now able to hit off the motions better than before; but what a singularly complicated motion it was. could it be expressed no more simply? yes, the curve so described by the planet is a comparatively simple one: it is a special kind of oval--the ellipse. strange that he had not thought of it before. it was a famous curve, for the greek geometers had studied it as one of the sections of a cone, but it was not so well known in kepler's time. the fact that the planets move in it has raised it to the first importance, and it is familiar enough to us now. but did it satisfy the law of speed? could the rate of description of areas be uniform with it? well, he tried the ellipse, and to his inexpressible delight he found that it did satisfy the condition of equable description of areas, if the sun was in one focus. so, moving the planet in a selected ellipse, with the sun in one focus, at a speed given by the equable area description, its position agreed with tycho's observations within the limits of the error of experiment. mars was finally conquered, and remains in his prison-house to this day. the orbit was found. [illustration: fig. 32.] in a paroxysm of delight kepler celebrates his victory by a triumphant figure, sketched actually on his geometrical diagram--the diagram which proves that the law of equable description of areas can hold good with an ellipse. the above is a tracing of it. such is a crude and bald sketch of the steps by which kepler rose to his great generalizations--the two laws which have immortalized his name. all the complications of epicycle, equant, deferent, excentric, and the like, were swept at once away, and an orbit of striking and beautiful properties substituted. well might he be called, as he was, "the legislator," or law interpreter, "of the heavens." [illustration: fig. 33.--if _s_ is the sun, a planet or comet moves from _p_ to _p_1_, from _p_2_ to _p_3_, and from _p_4_ to _p_5_ in the same time; if the shaded areas are equal.] he concludes his book on the motions of mars with a half comic appeal to the emperor to provide him with the sinews of war for an attack on mars's relations--father jupiter, brother mercury, and the rest--but the death of his unhappy patron in 1612 put an end to all these schemes, and reduced kepler to the utmost misery. while at prague his salary was in continual arrear, and it was with difficulty that he could provide sustenance for his family. he had been there eleven years, but they had been hard years of poverty, and he could leave without regret were it not that he should have to leave tycho's instruments and observations behind him. while he was hesitating what best to do, and reduced to the verge of despair, his wife, who had long been suffering from low spirits and despondency, and his three children, were taken ill; one of the sons died of small-pox, and the wife eleven days after of low fever and epilepsy. no money could be got at prague, so after a short time he accepted a professorship at linz, and withdrew with his two quite young remaining children. he provided for himself now partly by publishing a prophesying almanack, a sort of zadkiel arrangement--a thing which he despised, but the support of which he could not afford to do without. he is continually attacking and throwing sarcasm at astrology, but it was the only thing for which people would pay him, and on it after a fashion he lived. we do not find that his circumstances were ever prosperous, and though 8,000 crowns were due to him from bohemia he could not manage to get them paid. about this time occurred a singular interruption to his work. his old mother, of whose fierce temper something has already been indicated, had been engaged in a law-suit for some years near their old home in würtemberg. a change of judge having in process of time occurred, the defendant saw his way to turn the tables on the old lady by accusing her of sorcery. she was sent to prison, and condemned to the torture, with the usual intelligent idea of extracting a "voluntary" confession. kepler had to hurry from linz to interpose. he succeeded in saving her from the torture, but she remained in prison for a year or so. her spirit, however, was unbroken, for no sooner was she released than she commenced a fresh action against her accuser. but fresh trouble was averted by the death of the poor old dame at the age of nearly eighty. this narration renders the unflagging energy shown by her son in his mathematical wrestlings less surprising. interspersed with these domestic troubles, and with harassing and unsuccessful attempts to get his rights, he still brooded over his old problem of some possible connection between the distances of the planets from the sun and their times of revolution, _i.e._ the length of their years. it might well have been that there was no connection, that it was purely imaginary, like his old idea of the law of the successive distances of the planets, and like so many others of the guesses and fancies which he entertained and spent his energies in probing. but fortunately this time there was a connection, and he lived to have the joy of discovering it. the connection is this, that if one compares the distance of the different planets from the sun with the length of time they take to go round him, the cube of the respective distances is proportional to the square of the corresponding times. in other words, the ratio of r^3 to t^2 for every planet is the same. or, again, the length of a planet's year depends on the 3/2th power of its distance from the sun. or, once more, the speed of each planet in its orbit is as the inverse square-root of its distance from the sun. the product of the distance into the square of the speed is the same for each planet. this (however stated) is called kepler's third law. it welds the planets together, and shows them to be one system. his rapture on detecting the law was unbounded, and he breaks out into an exulting rhapsody:-"what i prophesied two-and-twenty years ago, as soon as i discovered the five solids among the heavenly orbits--what i firmly believed long before i had seen ptolemy's _harmonies_--what i had promised my friends in the title of this book, which i named before i was sure of my discovery--what sixteen years ago, i urged as a thing to be sought--that for which i joined tycho brahé, for which i settled in prague, for which i have devoted the best part of my life to astronomical contemplations, at length i have brought to light, and recognized its truth beyond my most sanguine expectations. it is not eighteen months since i got the first glimpse of light, three months since the dawn, very few days since the unveiled sun, most admirable to gaze upon, burst upon me. nothing holds me; i will indulge my sacred fury; i will triumph over mankind by the honest confession that i have stolen the golden vases of the egyptians to build up a tabernacle for my god far away from the confines of egypt. if you forgive me, i rejoice; if you are angry, i can bear it; the die is cast, the book is written, to be read either now or by posterity, i care not which; it may well wait a century for a reader, as god has waited six thousand years for an observer." soon after this great work his third book appeared: it was an epitome of the copernican theory, a clear and fairly popular exposition of it, which had the honour of being at once suppressed and placed on the list of books prohibited by the church, side by side with the work of copernicus himself, _de revolutionibus orbium coelestium_. this honour, however, gave kepler no satisfaction--it rather occasioned him dismay, especially as it deprived him of all pecuniary benefit, and made it almost impossible for him to get a publisher to undertake another book. still he worked on at the rudolphine tables of tycho, and ultimately, with some small help from vienna, completed them; but he could not get the means to print them. he applied to the court till he was sick of applying: they lay idle four years. at last he determined to pay for the type himself. what he paid it with, god knows, but he did pay it, and he did bring out the tables, and so was faithful to the behest of his friend. this great publication marks an era in astronomy. they were the first really accurate tables which navigators ever possessed; they were the precursors of our present _nautical almanack_. after this, the grand duke of tuscany sent kepler a golden chain, which is interesting inasmuch as it must really have come from galileo, who was in high favour at the italian court at this time. once more kepler made a determined attempt to get his arrears of salary paid, and rescue himself and family from their bitter poverty. he travelled to prague on purpose, attended the imperial meeting, and pleaded his own cause, but it was all fruitless; and exhausted by the journey, weakened by over-study, and disheartened by the failure, he caught a fever, and died in his fifty-ninth year. his body was buried at ratisbon, and a century ago a proposal was made to erect a marble monument to his memory, but nothing was done. it matters little one way or the other whether germany, having almost refused him bread during his life, should, a century and a half after his death, offer him a stone. [illustration: fig. 34.--portrait of kepler, older.] the contiguity of the lives of kepler and tycho furnishes a moral too obvious to need pointing out. what kepler might have achieved had he been relieved of those ghastly struggles for subsistence one cannot tell, but this much is clear, that had tycho been subjected to the same misfortune, instead of being born rich and being assisted by generous and enlightened patrons, he could have accomplished very little. his instruments, his observatory--the tools by which he did his work--would have been impossible for him. frederick and sophia of denmark, and rudolph of bohemia, are therefore to be remembered as co-workers with him. kepler, with his ill-health and inferior physical energy, was unable to command the like advantages. much, nevertheless, he did; more one cannot but feel he might have done had he been properly helped. besides, the world would have been free from the reproach of accepting the fruits of his bright genius while condemning the worker to a life of misery, relieved only by the beauty of his own thoughts and the ecstasy awakened in him by the harmony and precision of nature. concerning the method of kepler, the mode by which he made his discoveries, we must remember that he gives us an account of all the steps, unsuccessful as well as successful, by which he travelled. he maps out his route like a traveller. in fact he compares himself to columbus or magellan, voyaging into unknown lands, and recording his wandering route. this being remembered, it will be found that his methods do not differ so utterly from those used by other philosophers in like case. his imagination was perhaps more luxuriant and was allowed freer play than most men's, but it was nevertheless always controlled by rigid examination and comparison of hypotheses with fact. brewster says of him:--"ardent, restless, burning to distinguish himself by discovery, he attempted everything; and once having obtained a glimpse of a clue, no labour was too hard in following or verifying it. a few of his attempts succeeded--a multitude failed. those which failed seem to us now fanciful, those which succeeded appear to us sublime. but his methods were the same. when in search of what really existed he sometimes found it; when in pursuit of a chimæra he could not but fail; but in either case he displayed the same great qualities, and that obstinate perseverance which must conquer all difficulties except those really insurmountable." to realize what he did for astronomy, it is necessary for us now to consider some science still in its infancy. astronomy is so clear and so thoroughly explored now, that it is difficult to put oneself into a contemporary attitude. but take some other science still barely developed: meteorology, for instance. the science of the weather, the succession of winds and rain, sunshine and frost, clouds and fog, is now very much in the condition of astronomy before kepler. we have passed through the stage of ascribing atmospheric disturbances--thunderstorms, cyclones, earthquakes, and the like--to supernatural agency; we have had our copernican era: not perhaps brought about by a single individual, but still achieved. something of the laws of cyclone and anticyclone are known, and rude weather predictions across the atlantic are roughly possible. barometers and thermometers and anemometers, and all their tribe, represent the astronomical instruments in the island of huen; and our numerous meteorological observatories, with their continual record of events, represent the work of tycho brahé. observation is heaped on observation; tables are compiled; volumes are filled with data; the hours of sunshine are recorded, the fall of rain, the moisture in the air, the kind of clouds, the temperature--millions of facts; but where is the kepler to study and brood over them? where is the man to spend his life in evolving the beginnings of law and order from the midst of all this chaos? perhaps as a man he may not come, but his era will come. through this stage the science must pass, ere it is ready for the commanding intellect of a newton. but what a work it will be for the man, whoever he be that undertakes it--a fearful monotonous grind of calculation, hypothesis, hypothesis, calculation, a desperate and groping endeavour to reconcile theories with facts. a life of such labour, crowned by three brilliant discoveries, the world owes (and too late recognizes its obligation) to the harshly treated german genius, kepler. summary of facts for lectures iv and v in 1564, michael angelo died and galileo was born; in 1642, galileo died and newton was born. milton lived from 1608 to 1674. for teaching the plurality of worlds, with other heterodox doctrines, and refusing to recant, bruno, after six years' imprisonment in rome, was burnt at the stake on the 16th of february, 1600 a.d. a "natural" death in the dungeons of the inquisition saved antonio de dominis, the explainer of the rainbow, from the same fate, but his body and books were publicly burned at rome in 1624. the persecution of galileo began in 1615, became intense in 1632, and so lasted till his death and after. * * * * * galileo galilei, eldest son of vincenzo de bonajuti de galilei, a noble florentine, was born at pisa, 18th of february, 1564. at the age of 17 was sent to the university of pisa to study medicine. observed the swing of a pendulum and applied it to count pulse-beats. read euclid and archimedes, and could be kept at medicine no more. at 26 was appointed lecturer in mathematics at pisa. read bruno and became smitten with the copernican theory. controverted the aristotelians concerning falling bodies, at pisa. hence became unpopular and accepted a chair at padua, 1592. invented a thermometer. wrote on astronomy, adopting the ptolemaic system provisionally, and so opened up a correspondence with kepler, with whom he formed a friendship. lectured on the new star of 1604, and publicly renounced the old systems of astronomy. invented a calculating compass or "gunter's scale." in 1609 invented a telescope, after hearing of a dutch optician's discovery. invented the microscope soon after. rapidly completed a better telescope and began a survey of the heavens. on the 8th of january, 1610, discovered jupiter's satellites. observed the mountains in the moon, and roughly measured their height. explained the visibility of the new moon by _earth-shine_. was invited to the grand ducal court of tuscany by cosmo de medici, and appointed philosopher to that personage. discovered innumerable new stars, and the nebulæ. observed a triple appearance of saturn. discovered the phases of venus predicted by copernicus, and spots on the sun. wrote on floating bodies. tried to get his satellites utilized for determining longitude at sea. went to rome to defend the copernican system, then under official discussion, and as a result was formally forbidden ever to teach it. on the accession of pope urban viii. in 1623, galileo again visited rome to pay his respects, and was well received. in 1632 appeared his "dialogues" on the ptolemaic and copernican systems. summoned to rome, practically imprisoned, and "rigorously questioned." was made to recant 22nd of june, 1633. forbidden evermore to publish anything, or to teach, or receive friends. retired to arcetri in broken down health. death of his favourite daughter, sister maria celeste. wrote and meditated on the laws of motion. discovered the moon's libration. in 1637 he became blind. the rigour was then slightly relaxed and many visited him: among them john milton. died 8th of january, 1642, aged 78. as a prisoner of the inquisition his right to make a will or to be buried in consecrated ground was disputed. many of his manuscripts were destroyed. galileo, besides being a singularly clear-headed thinker and experimental genius, was also something of a musician, a poet, and an artist. he was full of humour as well as of solid common-sense, and his literary style is brilliant. of his scientific achievements those now reckoned most weighty, are the discovery of the laws of motion, and the laying of the foundations of mechanics. _particulars of jupiter's satellites, illustrating their obedience to kepler's third law._ ------------------------------------------------------------------------- | | | distance| | | t^2 | | time of | from | | | ---satellite.|diameter revolution | jupiter, | t^2 | d^3 | d^3 | miles.| in hours. |in jovian | | | which is | miles | (t) | radii. | | |practically | | | (d) | | | constant. ----------|-------|------------|----------|---------|---------|----------no. 1. | 2437 | 42·47 | 6·049 | 1803·7 | 221·44 | 8·149 no. 2. | 2188 | 85·23 | 9·623 | 7264·1 | 891·11 | 8·152 no. 3. | 3575 | 177·72 | 15·350 | 29488· | 3916·8 | 8·153 no. 4. | 3059 | 400·53 | 26·998 |160426· |19679· | 8·152 -------------------------------------------------------------------------the diameter of jupiter is 85,823 miles. _falling bodies._ since all bodies fall at the same rate, except for the disturbing effect of the resistance of the air, a statement of their rates of fall is of interest. in one second a freely falling body near the earth is found to drop 16 feet. in two seconds it drops 64 feet altogether, viz. 16 feet in the first, and 48 feet in the next second; because at the beginning of every second after the first it has the accumulated velocity of preceding seconds. the height fallen by a dropped body is not proportional to the time simply, but to what is rather absurdly called the square of the time, _i.e._ the time multiplied by itself. for instance, in 3 seconds it drops 9 × 16 = 144 feet; in 4 seconds 16 × 16, or 256 feet, and so on. the distances travelled in 1, 2, 3, 4, &c., seconds by a body dropped from rest and not appreciably resisted by the air, are 1, 4, 9, 16, 25, &c., respectively, each multiplied by the constant 16 feet. another way of stating the law is to say that the heights travelled in successive seconds proceed in the proportion 1, 3, 5, 7, 9, &c.; again multiplied by 16 feet in each case. [illustration: fig. 35.--curve described by a projectile, showing how it drops from the line of fire, _o d_, in successive seconds, the same distances _ap_, _bq_, _cr_, &c., as are stated above for a dropped body.] all this was experimentally established by galileo. a body takes half a second to drop 4 feet; and a quarter of a second to drop 1 foot. the easiest way of estimating a quarter of a second with some accuracy is to drop a bullet one foot. a bullet thrown or shot in any direction falls just as much as if merely dropped; but instead of falling from the starting-point it drops vertically from the line of fire. (see fig. 35). the rate of fall depends on the intensity of gravity; if it could be doubled, a body would fall twice as far in the same time; but to make it fall a given distance in half the time the intensity of gravity would have to be quadrupled. at a place where the intensity of gravity is 1/3600 of what it is here, a body would fall as far in a minute as it now falls in a second. such a place occurs at about the distance of the moon (_cf._ page 177). the fact that the height fallen through is proportional to the square of the time proves that the attraction of the earth or the intensity of gravity is sensibly constant throughout ordinary small ranges. over great distances of fall, gravity cannot be considered constant; so for things falling through great spaces the galilean law of the square of the time does not hold. the fact that things near the earth fall 16 feet in the first second proves that the intensity of ordinary terrestrial gravity is 32 british units of force per pound of matter. the fact that all bodies fall at the same rate (when the resistance of the air is eliminated), proves that weight is proportional to mass; or more explicitly, that the gravitative attraction of the earth on matter near its surface depends on the amount of that matter, as estimated by its inertia, and on nothing else. lecture iv galileo and the invention of the telescope contemporary with the life of kepler, but overlapping it at both ends, comes the great and eventful life of galileo galilei,[5] a man whose influence on the development of human thought has been greater than that of any man whom we have yet considered, and upon whom, therefore, it is necessary for us, in order to carry out the plan of these lectures, to bestow much time. a man of great and wide culture, a so-called universal genius, it is as an experimental philosopher that he takes the first rank. in this capacity he must be placed alongside of archimedes, and it is pretty certain that between the two there was no man of magnitude equal to either in experimental philosophy. it is perhaps too bold a speculation, but i venture to doubt whether in succeeding generations we find his equal in the domain of purely experimental science until we come to faraday. faraday was no doubt his superior, but i know of no other of whom the like can unhesitatingly be said. in mathematical and deductive science, of course, it is quite otherwise. kepler, for instance, and many men before and since, have far excelled galileo in mathematical skill and power, though at the same time his achievements in this department are by no means to be despised. born at pisa three centuries ago, on the very day that michael angelo lay dying in rome, he inherited from his father a noble name, cultivated tastes, a keen love of truth, and an impoverished patrimony. vincenzo de galilei, a descendant of the important bonajuti family, was himself a mathematician and a musician, and in a book of his still extant he declares himself in favour of free and open inquiry into scientific matters, unrestrained by the weight of authority and tradition. in all probability the son imbibed these precepts: certainly he acted on them. vincenzo, having himself experienced the unremunerative character of scientific work, had a horror of his son's taking to it, especially as in his boyhood he was always constructing ingenious mechanical toys, and exhibiting other marks of precocity. so the son was destined for business--to be, in fact, a cloth-dealer. but he was to receive a good education first, and was sent to an excellent convent school. here he made rapid progress, and soon excelled in all branches of classics and literature. he delighted in poetry, and in later years wrote several essays on dante, tasso, and ariosto, besides composing some tolerable poems himself. he played skilfully on several musical instruments, especially on the lute, of which indeed he became a master, and on which he solaced himself when quite an old man. besides this he seems to have had some skill as an artist, which was useful afterwards in illustrating his discoveries, and to have had a fine sensibility as an art critic, for we find several eminent painters of that day acknowledging the value of the opinion of the young galileo. perceiving all this display of ability, the father wisely came to the conclusion that the selling of woollen stuffs would hardly satisfy his aspirations for long, and that it was worth a sacrifice to send him to the university. so to the university of his native town he went, with the avowed object of studying medicine, that career seeming the most likely to be profitable. old vincenzo's horror of mathematics or science as a means of obtaining a livelihood is justified by the fact that while the university professor of medicine received 2,000 scudi a year, the professor of mathematics had only 60, that is £13 a year, or 7-1/2_d._ a day. so the son had been kept properly ignorant of such poverty-stricken subjects, and to study medicine he went. but his natural bent showed itself even here. for praying one day in the cathedral, like a good catholic as he was all his life, his attention was arrested by the great lamp which, after lighting it, the verger had left swinging to and fro. galileo proceeded to time its swings by the only watch he possessed--viz., his own pulse. he noticed that the time of swing remained as near as he could tell the same, notwithstanding the fact that the swings were getting smaller and smaller. by subsequent experiment he verified the law, and the isochronism of the pendulum was discovered. an immensely important practical discovery this, for upon it all modern clocks are based; and huyghens soon applied it to the astronomical clock, which up to that time had been a crude and quite untrustworthy instrument. the best clock which tycho brahé could get for his observatory was inferior to one that may now be purchased for a few shillings; and this change is owing to the discovery of the pendulum by galileo. not that he applied it to clocks; he was not thinking of astronomy, he was thinking of medicine, and wanted to count people's pulses. the pendulum served; and "pulsilogies," as they were called, were thus introduced to and used by medical practitioners. the tuscan court came to pisa for the summer months, for it was then a seaside place, and among the suite was ostillio ricci, a distinguished mathematician and old friend of the galileo family. the youth visited him, and one day, it is said, heard a lesson in euclid being given by ricci to the pages while he stood outside the door entranced. anyhow he implored ricci to help him into some knowledge of mathematics, and the old man willingly consented. so he mastered euclid and passed on to archimedes, for whom he acquired a great veneration. his father soon heard of this obnoxious proclivity, and did what he could to divert him back to medicine again. but it was no use. underneath his galen and hippocrates were secreted copies of euclid and archimedes, to be studied at every available opportunity. old vincenzo perceived the bent of genius to be too strong for him, and at last gave way. [illustration: fig. 36.--two forms of pulsilogy. the string is wound up till the swinging weight keeps time with the pulse, and the position of a bead or of an index connected with the string is then read on a scale or dial.] with prodigious rapidity the released philosopher now assimilated the elements of mathematics and physics, and at twenty-six we find him appointed for three years to the university chair of mathematics, and enjoying the paternally dreaded stipend of 7-1/2_d._ a day. now it was that he pondered over the laws of falling bodies. he verified, by experiment, the fact that the velocity acquired by falling down any slope of given height was independent of the angle of slope. also, that the height fallen through was proportional to the square of the time. another thing he found experimentally was that all bodies, heavy and light, fell at the same rate, striking the ground at the same time.[6] now this was clean contrary to what he had been taught. the physics of those days were a simple reproduction of statements in old books. aristotle had asserted certain things to be true, and these were universally believed. no one thought of trying the thing to see if it really were so. the idea of making an experiment would have savoured of impiety, because it seemed to tend towards scepticism, and cast a doubt on a reverend authority. young galileo, with all the energy and imprudence of youth (what a blessing that youth has a little imprudence and disregard of consequences in pursuing a high ideal!), as soon as he perceived that his instructors were wrong on the subject of falling bodies, instantly informed them of the fact. whether he expected them to be pleased or not is a question. anyhow, they were not pleased, but were much annoyed by his impertinent arrogance. it is, perhaps, difficult for us now to appreciate precisely their position. these doctrines of antiquity, which had come down hoary with age, and the discovery of which had reawakened learning and quickened intellectual life, were accepted less as a science or a philosophy, than as a religion. had they regarded aristotle as a verbally inspired writer, they could not have received his statements with more unhesitating conviction. in any dispute as to a question of fact, such as the one before us concerning the laws of falling bodies, their method was not to make an experiment, but to turn over the pages of aristotle; and he who could quote chapter and verse of this great writer was held to settle the question and raise it above the reach of controversy. it is very necessary for us to realize this state of things clearly, because otherwise the attitude of the learned of those days towards every new discovery seems stupid and almost insane. they had a crystallized system of truth, perfect, symmetrical--it wanted no novelty, no additions; every addition or growth was an imperfection, an excrescence, a deformity. progress was unnecessary and undesired. the church had a rigid system of dogma, which must be accepted in its entirety on pain of being treated as a heretic. philosophers had a cast-iron system of truth to match--a system founded upon aristotle--and so interwoven with the great theological dogmas that to question one was almost equivalent to casting doubt upon the other. in such an atmosphere true science was impossible. the life-blood of science is growth, expansion, freedom, development. before it could appear it must throw off these old shackles of centuries. it must burst its old skin, and emerge, worn with the struggle, weakly and unprotected, but free and able to grow and to expand. the conflict was inevitable, and it was severe. is it over yet? i fear not quite, though so nearly as to disturb science hardly at all. then it was different; it was terrible. honour to the men who bore the first shock of the battle! now aristotle had said that bodies fell at rates depending on their weight. a 5 lb. weight would fall five times as quick as a 1 lb. weight; a 50 lb. weight fifty times as quick, and so on. why he said so nobody knows. he cannot have tried. he was not above trying experiments, like his smaller disciples; but probably it never occurred to him to doubt the fact. it seems so natural that a heavy body should fall quicker than a light one; and perhaps he thought of a stone and a feather, and was satisfied. galileo, however, asserted that the weight did not matter a bit, that everything fell at the same rate (even a stone and a feather, but for the resistance of the air), and would reach the ground in the same time. and he was not content to be pooh-poohed and snubbed. he knew he was right, and he was determined to make every one see the facts as he saw them. so one morning, before the assembled university, he ascended the famous leaning tower, taking with him a 100 lb. shot and a 1 lb. shot. he balanced them on the edge of the tower, and let them drop together. together they fell, and together they struck the ground. the simultaneous clang of those two weights sounded the death-knell of the old system of philosophy, and heralded the birth of the new. but was the change sudden? were his opponents convinced? not a jot. though they had seen with their eyes, and heard with their ears, the full light of heaven shining upon them, they went back muttering and discontented to their musty old volumes and their garrets, there to invent occult reasons for denying the validity of the observation, and for referring it to some unknown disturbing cause. they saw that if they gave way on this one point they would be letting go their anchorage, and henceforward would be liable to drift along with the tide, not knowing whither. they dared not do this. no; they _must_ cling to the old traditions; they could not cast away their rotting ropes and sail out on to the free ocean of god's truth in a spirit of fearless faith. [illustration: fig. 37.--tower of pisa.] yet they had received a shock: as by a breath of fresh salt breeze and a dash of spray in their faces, they had been awakened out of their comfortable lethargy. they felt the approach of a new era. yes, it was a shock; and they hated the young galileo for giving it them--hated him with the sullen hatred of men who fight for a lost and dying cause. we need scarcely blame these men; at least we need not blame them overmuch. to say that they acted as they did is to say that they were human, were narrow-minded, and were the apostles of a lost cause. but _they_ could not know this; _they_ had no experience of the past to guide them; the conditions under which they found themselves were novel, and had to be met for the first time. conduct which was excusable then would be unpardonable now, in the light of all this experience to guide us. are there any now who practically repeat their error, and resist new truth? who cling to any old anchorage of dogma, and refuse to rise with the tide of advancing knowledge? there may be some even now. well, the unpopularity of galileo smouldered for a time, until, by another noble imprudence, he managed to offend a semi-royal personage, giovanni de medici, by giving his real opinion, when consulted, about a machine which de medici had invented for cleaning out the harbour of leghorn. he said it was as useless as it in fact turned out to be. through the influence of the mortified inventor he lost favour at court; and his enemies took advantage of the fact to render his chair untenable. he resigned before his three years were up, and retired to florence. his father at this time died, and the family were left in narrow circumstances. he had a brother and three sisters to provide for. he was offered a professorship at padua for six years by the senate of venice, and willingly accepted it. now began a very successful career. his introductory address was marked by brilliant eloquence, and his lectures soon acquired fame. he wrote for his pupils on the laws of motion, on fortifications, on sundials, on mechanics, and on the celestial globe: some of these papers are now lost, others have been printed during the present century. kepler sent him a copy of his new book, _mysterium cosmographicum_, and galileo in thanking him for it writes him the following letter:--[7] "i count myself happy, in the search after truth, to have so great an ally as yourself, and one who is so great a friend of the truth itself. it is really pitiful that there are so few who seek truth, and who do not pursue a perverse method of philosophising. but this is not the place to mourn over the miseries of our times, but to congratulate you on your splendid discoveries in confirmation of truth. i shall read your book to the end, sure of finding much that is excellent in it. i shall do so with the more pleasure, because _i have been for many years an adherent of the copernican system_, and it explains to me the causes of many of the appearances of nature which are quite unintelligible on the commonly accepted hypothesis. _i have collected many arguments for the purpose of refuting the latter_; but i do not venture to bring them to the light of publicity, for fear of sharing the fate of our master, copernicus, who, although he has earned immortal fame with some, yet with very many (so great is the number of fools) has become an object of ridicule and scorn. i should certainly venture to publish my speculations if there were more people like you. but this not being the case, i refrain from such an undertaking." kepler urged him to publish his arguments in favour of the copernican theory, but he hesitated for the present, knowing that his declaration would be received with ridicule and opposition, and thinking it wiser to get rather more firmly seated in his chair before encountering the storm of controversy. the six years passed away, and the venetian senate, anxious not to lose so bright an ornament, renewed his appointment for another six years at a largely increased salary. soon after this appeared a new star, the stella nova of 1604, not the one tycho had seen--that was in 1572--but the same that kepler was so much interested in. galileo gave a course of three lectures upon it to a great audience. at the first the theatre was over-crowded, so he had to adjourn to a hall holding 1000 persons. at the next he had to lecture in the open air. he took occasion to rebuke his hearers for thronging to hear about an ephemeral novelty, while for the much more wonderful and important truths about the permanent stars and facts of nature they had but deaf ears. but the main point he brought out concerning the new star was that it upset the received aristotelian doctrine of the immutability of the heavens. according to that doctrine the heavens were unchangeable, perfect, subject neither to growth nor to decay. here was a body, not a meteor but a real distant star, which had not been visible and which would shortly fade away again, but which meanwhile was brighter than jupiter. the staff of petrified professorial wisdom were annoyed at the appearance of the star, still more at galileo's calling public attention to it; and controversy began at padua. however, he accepted it; and now boldly threw down the gauntlet in favour of the copernican theory, utterly repudiating the old ptolemaic system which up to that time he had taught in the schools according to established custom. the earth no longer the only world to which all else in the firmament were obsequious attendants, but a mere insignificant speck among the host of heaven! man no longer the centre and cynosure of creation, but, as it were, an insect crawling on the surface of this little speck! all this not set down in crabbed latin in dry folios for a few learned monks, as in copernicus's time, but promulgated and argued in rich italian, illustrated by analogy, by experiment, and with cultured wit; taught not to a few scholars here and there in musty libraries, but proclaimed in the vernacular to the whole populace with all the energy and enthusiasm of a recent convert and a master of language! had a bombshell been exploded among the fossilized professors it had been less disturbing. but there was worse in store for them. a dutch optician, hans lippershey by name, of middleburg, had in his shop a curious toy, rigged up, it is said, by an apprentice, and made out of a couple of spectacle lenses, whereby, if one looked through it, the weather-cock of a neighbouring church spire was seen nearer and upside down. the tale goes that the marquis spinola, happening to call at the shop, was struck with the toy and bought it. he showed it to prince maurice of nassau, who thought of using it for military reconnoitring. all this is trivial. what is important is that some faint and inaccurate echo of this news found its way to padua, and into the ears of galileo. the seed fell on good soil. all that night he sat up and pondered. he knew about lenses and magnifying glasses. he had read kepler's theory of the eye, and had himself lectured on optics. could he not hit on the device and make an instrument capable of bringing the heavenly bodies nearer? who knew what marvels he might not so perceive! by morning he had some schemes ready to try, and one of them was successful. singularly enough it was not the same plan as the dutch optician's, it was another mode of achieving the same end. he took an old small organ pipe, jammed a suitably chosen spectacle glass into either end, one convex the other concave, and behold, he had the half of a wretchedly bad opera glass capable of magnifying three times. it was better than the dutchman's, however; it did not invert. it is easy to understand the general principle of a telescope. a general knowledge of the common magnifying glass may be assumed. roger bacon knew about lenses; and the ancients often refer to them, though usually as burning glasses. the magnifying power of globes of water must have been noticed soon after the discovery of glass and the art of working it. a magnifying glass is most simply thought of as an additional lens to the eye. the eye has a lens by which ordinary vision is accomplished, an extra glass lens strengthens it and enables objects to be seen nearer and therefore apparently bigger. but to apply a magnifying glass to distant objects is impossible. in order to magnify distant objects, another function of lenses has also to be employed, viz., their power of forming real images, the power on which their use as burning-glasses depends: for the best focus is an image of the sun. although the object itself is inaccessible, the image of it is by no means so, and to the image a magnifier can be applied. this is exactly what is done in the telescope; the object glass or large lens forms an image, which is then looked at through a magnifying glass or eye-piece. of course the image is nothing like so big as the object. for astronomical objects it is almost infinitely less; still it is an exact representation at an accessible place, and no one expects a telescope to show distant bodies as big as they really are. all it does is to show them bigger than they could be seen without it. but if the objects are not distant, the same principle may still be applied, and two lenses may be used, one to form an image, the other to magnify it; only if the object can be put where we please, we can easily place it so that its image is already much bigger than the object even before magnification by the eye lens. this is the compound microscope, the invention of which soon followed the telescope. in fact the two instruments shade off into one another, so that the reading telescope or reading microscope of a laboratory (for reading thermometers, and small divisions generally) goes by either name at random. the arrangement so far described depicts things on the retina the unaccustomed way up. by using a concave glass instead of a convex, and placing it so as to prevent any image being formed, except on the retina direct, this inconvenience is avoided. [illustration: fig. 38.--view of the half-moon in small telescope. the darker regions, or plains, used to be called "seas."] such a thing as galileo made may now be bought at a toy-shop for i suppose half a crown, and yet what a potentiality lay in that "glazed optic tube," as milton called it. away he went with it to venice and showed it to the signoria, to their great astonishment. "many noblemen and senators," says galileo, "though of advanced age, mounted to the top of one of the highest towers to watch the ships, which were visible through my glass two hours before they were seen entering the harbour, for it makes a thing fifty miles off as near and clear as if it were only five." among the people too the instrument excited the greatest astonishment and interest, so that he was nearly mobbed. the senate hinted to him that a present of the instrument would not be unacceptable, so galileo took the hint and made another for them. [illustration: fig. 39.--portion of the lunar surface more highly magnified, showing the shadows of a mountain range, deep pits, and other details.] they immediately doubled his salary at padua, making it 1000 florins, and confirmed him in the enjoyment of it for life. he now eagerly began the construction of a larger and better instrument. grinding the lenses with his own hands with consummate skill, he succeeded in making a telescope magnifying thirty times. thus equipped he was ready to begin a survey of the heavens. [illustration: fig. 40.--another portion of the lunar surface, showing a so-called crater or vast lava pool and other evidences of ancient heat unmodified by water.] the first object he carefully examined was naturally the moon. he found there everything at first sight very like the earth, mountains and valleys, craters and plains, rocks, and apparently seas. you may imagine the hostility excited among the aristotelian philosophers, especially no doubt those he had left behind at pisa, on the ground of his spoiling the pure, smooth, crystalline, celestial face of the moon as they had thought it, and making it harsh and rugged and like so vile and ignoble a body as the earth. [illustration: fig. 41.--lunar landscape showing earth. the earth would be a stationary object in the moon's sky: its only apparent motion being a slow oscillation as of a pendulum (the result of the moon's libration).] he went further, however, into heterodoxy than this--he not only made the moon like the earth, but he made the earth shine like the moon. the visibility of "the old moon in the new moon's arms" he explained by earth-shine. leonardo had given the same explanation a century before. now one of the many stock arguments against copernican theory of the earth being a planet like the rest was that the earth was dull and dark and did not shine. galileo argued that it shone just as much as the moon does, and in fact rather more--especially if it be covered with clouds. one reason of the peculiar brilliancy of venus is that she is a very cloudy planet.[8] seen from the moon the earth would look exactly as the moon does to us, only a little brighter and sixteen times as big (four times the diameter). [illustration: fig. 42.--galileo's method of estimating the height of lunar mountain. _ab'bc_ is the illuminated half of the moon. _sa_ is a solar ray just catching the peak of the mountain _m_. then by geometry, as _mn_ is to _ma_, so is _ma_ to _mb'_; whence the height of the mountain, _mn_, can be determined. the earth and spectator are supposed to be somewhere in the direction _ba_ produced, _i.e._ towards the top of the page.] galileo made a very good estimate of the height of lunar mountains, of which many are five miles high and some as much as seven. he did this simply by measuring from the half-moon's straight edge the distance at which their peaks caught the rising or setting sun. the above simple diagram shows that as this distance is to the diameter of the moon, so is the height of the sun-tipped mountain to the aforesaid distance. wherever galileo turned his telescope new stars appeared. the milky way, which had so puzzled the ancients, was found to be composed of stars. stars that appeared single to the eye were some of them found to be double; and at intervals were found hazy nebulous wisps, some of which seemed to be star clusters, while others seemed only a fleecy cloud. [illustration: fig. 43.--some clusters and nebulæ.] [illustration: fig. 44.--jupiter's satellites, showing the stages of their discovery.] now we come to his most brilliant, at least his most sensational, discovery. examining jupiter minutely on january 7, 1610, he noticed three little stars near it, which he noted down as fixing its then position. on the following night jupiter had moved to the other side of the three stars. this was natural enough, but was it moving the right way? on examination it appeared not. was it possible the tables were wrong? the next evening was cloudy, and he had to curb his feverish impatience. on the 10th there were only two, and those on the other side. on the 11th two again, but one bigger than the other. on the 12th the three re-appeared, and on the 13th there were four. no more appeared. jupiter then had moons like the earth, four of them in fact, and they revolved round him in periods which were soon determined. the reason why they were not all visible at first, and why their visibility so rapidly changes, is because they revolve round him almost in the plane of our vision, so that sometimes they are in front and sometimes behind him, while again at other times they plunge into his shadow and are thus eclipsed from the light of the sun which enables us to see them. a large modern telescope will show the moons when in front of jupiter, but small telescopes will only show them when clear of the disk and shadow. often all four can be thus seen, but three or two is a very common amount of visibility. quite a small telescope, such as a ship's telescope, if held steadily, suffices to show the satellites of jupiter, and very interesting objects they are. they are of habitable size, and may be important worlds for all we know to the contrary. the news of the discovery soon spread and excited the greatest interest and astonishment. many of course refused to believe it. some there were who having been shown them refused to believe their eyes, and asserted that although the telescope acted well enough for terrestrial objects, it was altogether false and illusory when applied to the heavens. others took the safer ground of refusing to look through the glass. one of these who would not look at the satellites happened to die soon afterwards. "i hope," says galileo, "that he saw them on his way to heaven." the way in which kepler received the news is characteristic, though by adding four to the supposed number of planets it might have seemed to upset his notions about the five regular solids. he says,[9] "i was sitting idle at home thinking of you, most excellent galileo, and your letters, when the news was brought me of the discovery of four planets by the help of the double eye-glass. wachenfels stopped his carriage at my door to tell me, when such a fit of wonder seized me at a report which seemed so very absurd, and i was thrown into such agitation at seeing an old dispute between us decided in this way, that between his joy, my colouring, and the laughter of us both, confounded as we were by such a novelty, we were hardly capable, he of speaking, or i of listening.... "on our separating, i immediately fell to thinking how there could be any addition to the number of planets without overturning my _mysterium cosmographicon_, published thirteen years ago, according to which euclid's five regular solids do not allow more than six planets round the sun. "but i am so far from disbelieving the existence of the four circumjovial planets that i long for a telescope to anticipate you if possible in discovering two round mars (as the proportion seems to me to require) six or eight round saturn, and one each round mercury and venus." [illustration: fig. 45.--eclipses of jupiter's satellites. the diagram shows the first (_i.e._ the nearest) moon in jupiter's shadow, the second as passing between earth and jupiter, and appearing to transit his disk, the third as on the verge of entering his shadow, and the fourth quite plainly and separately visible.] as an illustration of the opposite school, i will take the following extract from francesco sizzi, a florentine astronomer, who argues against the discovery thus:- "there are seven windows in the head, two nostrils, two eyes, two ears, and a mouth; so in the heavens there are two favourable stars, two unpropitious, two luminaries, and mercury alone undecided and indifferent. from which and many other similar phenomena of nature, such as the seven metals, &c., which it were tedious to enumerate, we gather that the number of planets is necessarily seven. "moreover, the satellites are invisible to the naked eye, and therefore can have no influence on the earth, and therefore would be useless, and therefore do not exist. "besides, the jews and other ancient nations as well as modern europeans have adopted the division of the week into seven days, and have named them from the seven planets: now if we increase the number of the planets this whole system falls to the ground." to these arguments galileo replied that whatever their force might be as a reason for believing beforehand that no more than seven planets would be discovered, they hardly seemed of sufficient weight to destroy the new ones when actually seen. writing to kepler at this time, galileo ejaculates: "oh, my dear kepler, how i wish that we could have one hearty laugh together! here, at padua, is the principal professor of philosophy whom i have repeatedly and urgently requested to look at the moon and planets through my glass, which he pertinaciously refuses to do. why are you not here? what shouts of laughter we should have at this glorious folly! and to hear the professor of philosophy at pisa labouring before the grand duke with logical arguments, as if with magical incantations, to charm the new planets out of the sky." a young german _protégé_ of kepler, martin horkey, was travelling in italy, and meeting galileo at bologna was favoured with a view through his telescope. but supposing that kepler must necessarily be jealous of such great discoveries, and thinking to please him, he writes, "i cannot tell what to think about these observations. they are stupendous, they are wonderful, but whether they are true or false i cannot tell." he concludes, "i will never concede his four new planets to that italian from padua though i die for it." so he published a pamphlet asserting that reflected rays and optical illusions were the sole cause of the appearance, and that the only use of the imaginary planets was to gratify galileo's thirst for gold and notoriety. when after this performance he paid a visit to his old instructor kepler, he got a reception which astonished him. however, he pleaded so hard to be forgiven that kepler restored him to partial favour, on this condition, that he was to look again at the satellites, and this time to see them and own that they were there. by degrees the enemies of galileo were compelled to confess to the truth of the discovery, and the next step was to outdo him. scheiner counted five, rheiter nine, and others went as high as twelve. some of these were imaginary, some were fixed stars, and four satellites only are known to this day.[10] here, close to the summit of his greatness, we must leave him for a time. a few steps more and he will be on the brow of the hill; a short piece of table-land, and then the descent begins. lecture v galileo and the inquisition one sinister event occurred while galileo was at padua, some time before the era we have now arrived at, before the invention of the telescope--two years indeed after he had first gone to padua; an event not directly concerning galileo, but which i must mention because it must have shadowed his life both at the time and long afterwards. it was the execution of giordano bruno for heresy. this eminent philosopher had travelled largely, had lived some time in england, had acquired new and heterodox views on a variety of subjects, and did not hesitate to propound them even after he had returned to italy. the copernican doctrine of the motion of the earth was one of his obnoxious heresies. being persecuted to some extent by the church, bruno took refuge in venice--a free republic almost independent of the papacy--where he felt himself safe. galileo was at padua hard by: the university of padua was under the government of the senate of venice: the two men must in all probability have met. well, the inquisition at rome sent messengers to venice with a demand for the extradition of bruno--they wanted him at rome to try him for heresy. in a moment of miserable weakness the venetian republic gave him up, and bruno was taken to rome. there he was tried, and cast into the dungeons for six years, and because he entirely refused to recant, was at length delivered over to the secular arm and burned at the stake on 16th february, anno domini 1600. this event could not but have cast a gloom over the mind of lovers and expounders of truth, and the lesson probably sank deep into galileo's soul. in dealing with these historic events will you allow me to repudiate once for all the slightest sectarian bias or meaning. i have nothing to do with catholic or protestant as such. i have nothing to do with the church of rome as such. i am dealing with the history of science. but historically at one period science and the church came into conflict. it was not specially one church rather than another--it was the church in general, the only one that then existed in those countries. historically, i say, they came into conflict, and historically the church was the conqueror. it got its way; and science, in the persons of bruno, galileo, and several others, was vanquished. such being the facts, there is no help but to mention them in dealing with the history of science. doubtless _now_ the church regards it as an unhappy victory, and gladly would ignore this painful struggle. this, however, is impossible. with their creed the churchmen of that day could act in no other way. they were bound to prosecute heresy, and they were bound to conquer in the struggle or be themselves shattered. but let me insist on the fact that no one accuses the ecclesiastical courts of crime or evil motives. they attacked heresy after their manner, as the civil courts attacked witchcraft after _their_ manner. both erred grievously, but both acted with the best intentions. we must remember, moreover, that his doctrines were scientifically heterodox, and the university professors of that day were probably quite as ready to condemn them as the church was. to realise the position we must think of some subjects which _to-day_ are scientifically heterodox, and of the customary attitude adopted towards them by persons of widely differing creeds. if it be contended now, as it is, that the ecclesiastics treated galileo well, i admit it freely: they treated him as well as they possibly could. they overcame him, and he recanted; but if he had not recanted, if he had persisted in his heresy, they would--well, they would still have treated his soul well, but they would have set fire to his body. their mistake consisted not in cruelty, but in supposing themselves the arbiters of eternal truth; and by no amount of slurring and glossing over facts can they evade the responsibility assumed by them on account of this mistaken attitude. i am not here attacking the dogma of papal infallibility: it is historically, i believe, quite unaffected by the controversy respecting the motion of the earth, no papal edict _ex cathedrâ_ having been promulgated on the subject. we left galileo standing at his telescope and beginning his survey of the heavens. we followed him indeed through a few of his first great discoveries--the discovery of the mountains and other variety of surface in the moon, of the nebulæ and a multitude of faint stars, and lastly of the four satellites of jupiter. this latter discovery made an immense sensation, and contributed its share to his removal from padua, which quickly followed it, as i shall shortly narrate; but first i think it will be best to continue our survey of his astronomical discoveries without regard to the place whence they were made. before the end of the year galileo had made another discovery--this time on saturn. but to guard against the host of plagiarists and impostors, he published it in the form of an anagram, which, at the request of the emperor rudolph (a request probably inspired by kepler), he interpreted; it ran thus: the furthest planet is triple. very soon after he found that venus was changing from a full moon to a half moon appearance. he announced this also by an anagram, and waited till it should become a crescent, which it did. this was a dreadful blow to the anti-copernicans, for it removed the last lingering difficulty to the reception of the copernican doctrine. [illustration: fig. 46.--old drawings of saturn by different observers, with the imperfect instruments of that day. the first is galileo's idea of what he saw.] copernicus had predicted, indeed, a hundred years before, that, if ever our powers of sight were sufficiently enhanced, venus and mercury would be seen to have phases like the moon. and now galileo with his telescope verifies the prediction to the letter. here was a triumph for the grand old monk, and a bitter morsel for his opponents. castelli writes: "this must now convince the most obstinate." but galileo, with more experience, replies:--"you almost make me laugh by saying that these clear observations are sufficient to convince the most obstinate; it seems you have yet to learn that long ago the observations were enough to convince those who are capable of reasoning, and those who wish to learn the truth; but that to convince the obstinate, and those who care for nothing beyond the vain applause of the senseless vulgar, not even the testimony of the stars would suffice, were they to descend on earth to speak for themselves. let us, then, endeavour to procure some knowledge for ourselves, and rest contented with this sole satisfaction; but of advancing in popular opinion, or of gaining the assent of the book-philosophers, let us abandon both the hope and the desire." [illustration: fig. 47.--phases of venus. showing also its apparent variations in size by reason of its varying distance from the earth. when fully illuminated it is necessarily most distant. it looks brightest to us when a broad crescent.] what a year's work it had been! in twelve months observational astronomy had made such a bound as it has never made before or since. why did not others make any of these observations? because no one could make telescopes like galileo. he gathered pupils round him however, and taught them how to work the lenses, so that gradually these instruments penetrated europe, and astronomers everywhere verified his splendid discoveries. but still he worked on, and by march in the very next year, he saw something still more hateful to the aristotelian philosophers, viz. spots on the sun. [illustration: fig. 48.] if anything was pure and perfect it was the sun, they said. was this impostor going to blacken its face too? well, there they were. they slowly formed and changed, and by moving all together showed him that the sun rotated about once a month. before taking leave of galileo's astronomical researches, i must mention an observation made at the end of 1612, that the apparent triplicity of saturn (fig. 46) had vanished. [illustration: fig. 49.--a portion of the sun's disk as seen in a powerful modern telescope.] "looking on saturn within these few days, i found it solitary, without the assistance of its accustomed stars, and in short perfectly round and defined, like jupiter, and such it still remains. now what can be said of so strange a metamorphosis? are perhaps the two smaller stars consumed like spots on the sun? have they suddenly vanished and fled? or has saturn devoured his own children? or was the appearance indeed fraud and illusion, with which the glasses have so long time mocked me and so many others who have so often observed with me? now perhaps the time is come to revive the withering hopes of those, who, guided by more profound contemplations, have fathomed all the fallacies of the new observations and recognized their impossibility! i cannot resolve what to say in a chance so strange, so new, so unexpected. the shortness of time, the unexampled occurrence, the weakness of my intellect, the terror of being mistaken, have greatly confounded me." however, he plucked up courage, and conjectured that the two attendants would reappear, by revolving round the planet. [illustration: fig. 50.--saturn and his rings, as seen under the most favourable circumstances.] the real reason of their disappearance is well known to us now. the plane of saturn's rings oscillates slowly about our line of sight, and so we sometimes see them edgeways and sometimes with a moderate amount of obliquity. the rings are so thin that, when turned precisely edgeways, they become invisible. the two imaginary attendants were the most conspicuous portions of the ring, subsequently called _ansæ_. i have thought it better not to interrupt this catalogue of brilliant discoveries by any biographical details; but we must now retrace our steps to the years 1609 and 1610, the era of the invention of the telescope. by this time galileo had been eighteen years at padua, and like many another man in like case, was getting rather tired of continual lecturing. moreover, he felt so full of ideas that he longed to have a better opportunity of following them up, and more time for thinking them out. now in the holidays he had been accustomed to return to his family home at pisa, and there to come a good deal into contact with the grand-ducal house of tuscany. young cosmo di medici became in fact his pupil, and arrived at man's estate with the highest opinion of the philosopher. this young man had now come to the throne as cosmo ii., and to him galileo wrote saying how much he should like more time and leisure, how full he was of discoveries if he only had the chance of a reasonable income without the necessity of consuming so large a portion of his time in elementary teaching, and practically asking to be removed to some position in the court. nothing was done for a time, but negotiations proceeded, and soon after the discovery of jupiter's satellites cosmo wrote making a generous offer, which galileo gladly and enthusiastically accepted, and at once left padua for florence. all his subsequent discoveries date from florence. thus closed his brilliant and happy career as a professor at the university of padua. he had been treated well: his pay had become larger than that of any professor of mathematics up to that time; and, as you know, immediately after his invention of the telescope the venetian senate, in a fit of enthusiasm, had doubled it and secured it to him for life wherever he was. to throw up his chair and leave the place the very next year scarcely seems a strictly honourable procedure. it was legal enough no doubt, and it is easy for small men to criticize a great one, but nevertheless i think we must admit that it is a step such as a man with a keen sense of honour would hardly have taken. one quite feels and sympathizes with the temptation. not emolument, but leisure; freedom from harassing engagements and constant teaching, and liberty to prosecute his studies day and night without interference: this was the golden prospect before him. he yielded, but one cannot help wishing he had not. as it turned out it was a false step--the first false step of his public career. when made it was irretrievable, and it led to great misery. at first it seemed brilliant enough. the great philosopher of the tuscan court was courted and flattered by princes and nobles, he enjoyed a world-wide reputation, lived as luxuriously as he cared for, had his time all to himself, and lectured but very seldom, on great occasions or to a few crowned heads. his position was in fact analogous to that of tycho brahé in his island of huen. misfortune overtook both. in tycho's case it arose mainly from the death of his patron. in galileo's it was due to a more insidious cause, to understand which cause aright we must remember the political divisions of italy at that date. tuscany was a papal state, and thought there was by no means free. venice was a free republic, and was even hostile to the papacy. in 1606 the pope had placed it under an interdict. in reply it had ejected every jesuit. out of this atmosphere of comparative enlightenment and freedom into that hotbed of mediævalism and superstition went galileo with his eyes open. keen was the regret of his paduan and venetian friends; bitter were their remonstrances and exhortations. but he was determined to go, and, not without turning some of his old friends into enemies, he went. seldom has such a man made so great a mistake: never, i suppose, has one been so cruelly punished for it. [illustration: fig. 51.--map of italy.] we must remember, however, that galileo, though by no means a saint, was yet a really religious man, a devout catholic and thorough adherent of the church, so that he would have no dislike to place himself under her sway. moreover, he had been born a tuscan, his family had lived at florence or pisa, and it felt like going home. his theological attitude is worthy of notice, for he was not in the least a sceptic. he quite acquiesces in the authority of the bible, especially in all matters concerning faith and conduct; as to its statements in scientific matters, he argues that we are so liable to misinterpret their meaning that it is really easier to examine nature for truth in scientific matters, and that when direct observation and scripture seem to clash, it is because of our fallacious interpretation of one or both of them. he is, in fact, what one now calls a "reconciler." it is curious to find such a man prosecuted for heresy, when to-day his opinions are those of the orthodox among the orthodox. but so it ever is, and the heresy of one generation becomes the commonplace of the next. he accepts joshua's miracle, for instance, not as a striking poem, but as a literal fact; and he points out how much more simply it could be done on the copernican system by stopping the earth's rotation for a short time, than by stopping the sun and moon and all the host of heaven as on the old ptolemaic system, or again by stopping only the sun and not any of the other bodies, and so throwing astronomy all wrong. this reads to us like satire, but no doubt it was his genuine opinion. these scriptural reconciliations of his, however, angered the religious authorities still more. they said it was bad enough for this heretic to try and upset old _scientific_ beliefs, and to spoil the face of _nature_ with his infidel discoveries, but at least he might leave the bible alone; and they addressed an indignant remonstrance to rome, to protect it from the hands of ignorant laymen. thus, wherever he turned he encountered hostility. of course he had many friends--some of them powerful like cosmo, all of them faithful and sincere. but against the power of rome what could they do? cosmo dared no more than remonstrate, and ultimately his successor had to refrain from even this, so enchained and bound was the spirit of the rulers of those days; and so when his day of tribulation came he stood alone and helpless in the midst of his enemies. you may wonder, perhaps, why this man should excite so much more hostility than many another man who was suffered to believe and teach much the same doctrines unmolested. but no other man had made such brilliant and exciting discoveries. no man stood so prominently forward in the eyes of all christendom as the champion of the new doctrines. no other man stated them so clearly and forcibly, nor drove them home with such brilliant and telling illustrations. and again, there was the memory of his early conflict with the aristotelians at pisa, of his scornful and successful refutation of their absurdities. all this made him specially obnoxious to the aristotelian jesuits in their double capacity both of priests and of philosophers, and they singled him out for relentless official persecution. not yet, however, is he much troubled by them. the chief men at rome have not yet moved. messages, however, keep going up from tuscany to rome respecting the teachings of this man, and of the harm he is doing by his pertinacious preaching of the copernican doctrine that the earth moves. at length, in 1615, pope paul v. wrote requesting him to come to rome to explain his views. he went, was well received, made a special friend of cardinal barberino--an accomplished man in high position, who became in fact the next pope. galileo showed cardinals and others his telescope, and to as many as would look through it he showed jupiter's satellites and his other discoveries. he had a most successful visit. he talked, he harangued, he held forth in the midst of fifteen or twenty disputants at once, confounding his opponents and putting them to shame. his method was to let the opposite arguments be stated as fully and completely as possible, himself aiding, and often adducing the most forcible and plausible arguments against his own views; and then, all having been well stated, he would proceed to utterly undermine and demolish the whole fabric, and bring out the truth in such a way as to convince all honest minds. it was this habit that made him such a formidable antagonist. he never shrank from meeting an opposing argument, never sought to ignore it, or cloak it in a cloud of words. every hostile argument he seemed to delight in, as a foe to be crushed, and the better and stronger they sounded the more he liked them. he knew many of them well, he invented a number more, and had he chosen could have out-argued the stoutest aristotelian on his own grounds. thus did he lead his adversaries on, almost like socrates, only to ultimately overwhelm them in a more hopeless rout. all this in rome too, in the heart of the catholic world. had he been worldly-wise, he would certainly have kept silent and unobtrusive till he had leave to go away again. but he felt like an apostle of the new doctrines, whose mission it was to proclaim them even in this centre of the world and of the church. well, he had an audience with the pope--a chat an hour long--and the two parted good friends, mutually pleased with each other. he writes that he is all right now, and might return home when he liked. but the question began to be agitated whether the whole system of copernicus ought not to be condemned as impious and heretical. this view was persistently urged upon the pope and college of cardinals, and it was soon to be decided upon. had galileo been unfaithful to the church he could have left them to stultify themselves in any way they thought proper, and himself have gone; but he felt supremely interested in the result, and he stayed. he writes:- "so far as concerns the clearing of my own character, i might return home immediately; but although this new question regards me no more than all those who for the last eighty years have supported those opinions both in public and private, yet, as perhaps i may be of some assistance in that part of the discussion which depends on the knowledge of truths ascertained by means of the sciences which i profess, i, as a zealous and catholic christian, neither can nor ought to withhold that assistance which my knowledge affords, and this business keeps me sufficiently employed." it is possible that his stay was the worst thing for the cause he had at heart. anyhow, the result was that the system was condemned, and both the book of copernicus and the epitome of it by kepler were placed on the forbidden list,[11] and galileo himself was formally ordered never to teach or to believe the motion of the earth. he quitted rome in disgust, which before long broke out in satire. the only way in which he could safely speak of these views now was as if they were hypothetical and uncertain, and so we find him writing to the archduke leopold, with a presentation copy of his book on the tides, the following:- "this theory occurred to me when in rome whilst the theologians were debating on the prohibition of copernicus's book, and of the opinion maintained in it of the motion of the earth, which i at that time believed: until it pleased those gentlemen to suspend the book, and declare the opinion false and repugnant to the holy scriptures. now, as i know how well it becomes me to obey and believe the decisions of my superiors, which proceed out of more knowledge than the weakness of my intellect can attain to, this theory which i send you, which is founded on the motion of the earth, i now look upon as a fiction and a dream, and beg your highness to receive it as such. but as poets often learn to prize the creations of their fancy, so in like manner do i set some value on this absurdity of mine. it is true that when i sketched this little work i did hope that copernicus would not, after eighty years, be convicted of error; and i had intended to develop and amplify it further, but a voice from heaven suddenly awakened me, and at once annihilated all my confused and entangled fancies." this sarcasm, if it had been in print, would probably have been dangerous. it was safe in a private letter, but it shows us his real feelings. however, he was left comparatively quiet for a time. he was getting an old man now, and passed the time studiously enough, partly at his house in florence, partly at his villa in arcetri, a mile or so out of the town. here was a convent, and in it his two daughters were nuns. one of them, who passed under the name of sister maria celeste, seems to have been a woman of considerable capacity--certainly she was of a most affectionate disposition--and loved and honoured her father in the most dutiful way. this was a quiet period of his life, spoiled only by occasional fits of illness and severe rheumatic pains, to which the old man was always liable. many little circumstances are known of this peaceful time. for instance, the convent clock won't go, and galileo mends it for them. he is always doing little things for them, and sending presents to the lady superior and his two daughters. he was occupied now with problems in hydrostatics, and on other matters unconnected with astronomy: a large piece of work which i must pass over. most interesting and acute it is, however. in 1623, when the old pope died, there was elected to the papal throne, as urban viii., cardinal barberino, a man of very considerable enlightenment, and a personal friend of galileo's, so that both he and his daughters rejoice greatly, and hope that things will come all right, and the forbidding edict be withdrawn. the year after this election he manages to make another journey to rome to compliment his friend on his elevation to the pontifical chair. he had many talks with urban, and made himself very agreeable. urban wrote to the grand duke ferdinand, son of cosmo:- "for we find in him not only literary distinction but also love of piety, and he is strong in those qualities by which pontifical good will is easily obtainable. and now, when he has been brought to this city to congratulate us on our elevation, we have very lovingly embraced him; nor can we suffer him to return to the country whither your liberality recalls him without an ample provision of pontifical love. and that you may know how dear he is to us, we have willed to give him this honourable testimonial of virtue and piety. and we further signify that every benefit which you shall confer upon him, imitating or even surpassing your father's liberality, will conduce to our gratification." encouraged, doubtless, by these marks of approbation, and reposing too much confidence in the individual good will of the pope, without heeding the crowd of half-declared enemies who were seeking to undermine his reputation, he set about, after his return to florence, his greatest literary and most popular work, _dialogues on the ptolemaic and copernican systems_. this purports to be a series of four conversations between three characters: salviati, a copernican philosopher; sagredo, a wit and scholar, not specially learned, but keen and critical, and who lightens the talk with chaff; simplicio, an aristotelian philosopher, who propounds the stock absurdities which served instead of arguments to the majority of men. the conversations are something between plato's _dialogues_ and sir arthur helps's _friends in council_. the whole is conducted with great good temper and fairness; and, discreetly enough, no definite conclusion is arrived at, the whole being left in abeyance as if for a fifth and decisive dialogue, which, however, was never written, and perhaps was only intended in case the reception was favourable. the preface also sets forth that the object of the writer is to show that the roman edict forbidding the copernican doctrine was not issued in ignorance of the facts of the case, as had been maliciously reported, and that he wishes to show how well and clearly it was all known beforehand. so he says the dialogue on the copernican side takes up the question purely as a mathematical hypothesis or speculative figment, and gives it every artificial advantage of which the theory is capable. this piece of caution was insufficient to blind the eyes of the cardinals; for in it the arguments in favour of the earth's motion are so cogent and unanswerable, and are so popularly stated, as to do more in a few years to undermine the old system than all that he had written and spoken before. he could not get it printed for two years after he had written it, and then only got consent through a piece of carelessness or laziness on the part of the ecclesiastical censor through whose hands the manuscript passed--for which he was afterwards dismissed. however, it did appear, and was eagerly read; the more, perhaps, as the church at once sought to suppress it. the aristotelians were furious, and represented to the pope that he himself was the character intended by simplicio, the philosopher whose opinions get alternately refuted and ridiculed by the other two, till he is reduced to an abject state of impotence. the idea that galileo had thus cast ridicule upon his friend and patron is no doubt a gratuitous and insulting libel: there is no telling whether or not urban believed it, but certainly his countenance changed to galileo henceforward, and whether overruled by his cardinals, or actuated by some other motive, his favour was completely withdrawn. the infirm old man was instantly summoned to rome. his friends pleaded his age--he was now seventy--his ill-health, the time of year, the state of the roads, the quarantine existing on account of the plague. it was all of no avail, to rome he must go, and on the 14th of february he arrived. [illustration: fig. 52.--portrait of galileo.] his daughter at arcetri was in despair; and anxiety and fastings and penances self-inflicted on his account, dangerously reduced her health. at rome he was not imprisoned, but he was told to keep indoors, and show himself as little as possible. he was allowed, however, to stay at the house of the tuscan ambassador instead of in gaol. by april he was removed to the chambers of the inquisition, and examined several times. here, however, the anxiety was too much, and his health began to give way seriously; so, before long, he was allowed to return to the ambassador's house; and, after application had been made, was allowed to drive in the public garden in a half-closed carriage. thus in every way the inquisition dealt with him as leniently as they could. he was now their prisoner, and they might have cast him into their dungeons, as many another had been cast. by whatever they were influenced--perhaps the pope's old friendship, perhaps his advanced age and infirmities--he was not so cruelly used. still, they had their rules; he _must_ be made to recant and abjure his heresy; and, if necessary, torture must be applied. this he knew well enough, and his daughter knew it, and her distress may be imagined. moreover, it is not as if they had really been heretics, as if they hated or despised the church of rome. on the contrary, they loved and honoured the church. they were sincere and devout worshippers, and only on a few scientific matters did galileo presume to differ from his ecclesiastical superiors: his disagreement with them occasioned him real sorrow; and his dearest hope was that they could be brought to his way of thinking and embrace the truth. every time he was sent for by the inquisition he was in danger of torture unless he recanted. all his friends urged him repeatedly to submit. they said resistance was hopeless and fatal. within the memory of men still young, giordano bruno had been burnt alive for a similar heresy. this had happened while galileo was at padua. venice was full of it. and since that, only eight years ago indeed, antonio de dominis, archbishop of salpetria, had been sentenced to the same fate: "to be handed over to the secular arm to be dealt with as mercifully as possible without the shedding of blood." so ran the hideous formula condemning a man to the stake. after his sentence, this unfortunate man died in the dungeons in which he had been incarcerated six years--died what is called a "natural" death; but the sentence was carried out, notwithstanding, on his lifeless body and his writings. his writings for which he had been willing to die! these were the tender mercies of the inquisition; and this was the kind of meaning lurking behind many of their well-sounding and merciful phrases. for instance, what they call "rigorous examination," we call "torture." let us, however, remember in our horror at this mode of compelling a prisoner to say anything they wished, that they were a legally constituted tribunal; that they acted with well established rules, and not in passion; and that torture was a recognized mode of extracting evidence, not only in ecclesiastical but in civil courts, at that date. all this, however, was but poor solace to the pitiable old philosopher, thus ruthlessly haled up and down, questioned and threatened, threatened and questioned, receiving agonizing letters from his daughter week by week, and trying to keep up a little spirit to reply as happily and hopefully as he could. this condition of things could not go on. from february to june the suspense lasted. on the 20th of june he was summoned again, and told he would be wanted all next day for a rigorous examination. early in the morning of the 21st he repaired thither, and the doors were shut. out of those chambers of horror he did not reappear till the 24th. what went on all those three days no one knows. he himself was bound to secrecy. no outsider was present. the records of the inquisition are jealously guarded. that he was technically tortured is certain; that he actually underwent the torment of the rack is doubtful. much learning has been expended upon the question, especially in germany. several eminent scholars have held the fact of actual torture to be indisputable (geometrically certain, one says), and they confirm it by the hernia from which he afterwards suffered, this being a well-known and frequent consequence. other equally learned commentators, however, deny that the last stage was reached. for there are five stages all laid down in the rules of the inquisition, and steadily adhered to in a rigorous examination, at each stage an opportunity being given for recantation, every utterance, groan, or sigh being strictly recorded. the recantation so given has to be confirmed a day or two later, under pain of a precisely similar ordeal. the five stages are:--1st. the official threat in the court. 2nd. the taking to the door of the torture chamber and renewing the official threat. 3rd. the taking inside and showing the instruments. 4th. undressing and binding upon the rack. 5th. _territio realis._ through how many of these ghastly acts galileo passed i do not know. i hope and believe not the last. there are those who lament that he did not hold out, and accept the crown of martyrdom thus offered to him. had he done so we know his fate--a few years' languishing in the dungeons, and then the flames. whatever he ought to have done, he did not hold out--he gave way. at one stage or another of the dread ordeal he said: "i am in your hands. i will say whatever you wish." then was he removed to a cell while his special form of perjury was drawn up. the next day, clothed as a penitent, the venerable old man was taken to the convent of minerva, where the cardinals and prelates were assembled for the purpose of passing judgment upon him. the text of the judgment i have here, but it is too long to read. it sentences him--1st. to the abjuration. 2nd. to formal imprisonment for life. 3rd. to recite the seven penitential psalms every week. ten cardinals were present; but, to their honour be it said, three refused to sign; and this blasphemous record of intolerance and bigoted folly goes down the ages with the names of seven cardinals immortalized upon it. this having been read, he next had to read word for word the abjuration which had been drawn up for him, and then sign it. the abjuration of galileo. "i, galileo galilei, son of the late vincenzo galilei, of florence, aged seventy years, being brought personally to judgment, and kneeling before you most eminent and most reverend lords cardinals, general inquisitors of the universal christian republic against heretical depravity, having before my eyes the holy gospels, which i touch with my own hands, swear that i have always believed, and now believe, and with the help of god will in future believe, every article which the holy catholic and apostolic church of rome holds, teaches, and preaches. but because i have been enjoined by this holy office altogether to abandon the false opinion which maintains that the sun is the centre and immovable, and forbidden to hold, defend, or teach the said false doctrine in any manner, and after it hath been signified to me that the said doctrine is repugnant with the holy scripture, i have written and printed a book, in which i treat of the same doctrine now condemned, and adduce reasons with great force in support of the same, without giving any solution, and therefore have been judged grievously suspected of heresy; that is to say, that i held and believed that the sun is the centre of the universe and is immovable, and that the earth is not the centre and is movable; willing, therefore, to remove from the minds of your eminences, and of every catholic christian, this vehement suspicion rightfully entertained towards me, with a sincere heart and unfeigned faith, i abjure, curse, and detest the said errors and heresies, and generally every other error and sect contrary to holy church; and i swear that i will never more in future say or assert anything verbally, or in writing, which may give rise to a similar suspicion of me; but if i shall know any heretic, or any one suspected of heresy, that i will denounce him to this holy office, or to the inquisitor or ordinary of the place where i may be; i swear, moreover, and promise, that i will fulfil and observe fully, all the penances which have been or shall be laid on me by this holy office. but if it shall happen that i violate any of my said promises, oaths, and protestations (which god avert!), i subject myself to all the pains and punishments which have been decreed and promulgated by the sacred canons, and other general and particular constitutions, against delinquents of this description. so may god help me, and his holy gospels which i touch with my own hands. i, the above-named galileo galilei, have abjured, sworn, promised, and bound myself as above, and in witness thereof with my own hand have subscribed this present writing of my abjuration, which i have recited word for word. at rome, in the convent of minerva, 22nd june, 1633. i, galileo galilei, have abjured as above with my own hand." those who believe the story about his muttering to a friend, as he rose from his knees, "e pur si muove," do not realize the scene. 1st. there was no friend in the place. 2nd. it would have been fatally dangerous to mutter anything before such an assemblage. 3rd. he was by this time an utterly broken and disgraced old man; wishful, of all things, to get away and hide himself and his miseries from the public gaze; probably with his senses deadened and stupefied by the mental sufferings he had undergone, and no longer able to think or care about anything--except perhaps his daughter,--certainly not about any motion of this wretched earth. far and wide the news of the recantation spread. copies of the abjuration were immediately sent to all universities, with instructions to the professors to read it publicly. at florence, his home, it was read out in the cathedral church, all his friends and adherents being specially summoned to hear it. for a short time more he was imprisoned in rome; but at length was permitted to depart, never more of his own will to return. he was allowed to go to siena. here his daughter wrote consolingly, rejoicing at his escape, and saying how joyfully she already recited the penitential psalms for him, and so relieved him of that part of his sentence. but the poor girl was herself, by this time, ill--thoroughly worn out with anxiety and terror; she lay, in fact, on what proved to be her death-bed. her one wish was to see her dearest lord and father, so she calls him, once more. the wish was granted. his prison was changed, by orders from rome, from siena to arcetri, and once more father and daughter embraced. six days after this she died. the broken-hearted old man now asks for permission to go to live in florence, but is met with the stern answer that he is to stay at arcetri, is not to go out of the house, is not to receive visitors, and that if he asks for more favours, or transgresses the commands laid upon him, he is liable to be haled back to rome and cast into a dungeon. these harsh measures were dictated, not by cruelty, but by the fear of his still spreading heresy by conversation, and so he was to be kept isolated. idle, however, he was not and could not be. he often complains that his head is too busy for his body. in the enforced solitude of arcetri he was composing those dialogues on motion which are now reckoned his greatest and most solid achievement. in these the true laws of motion are set forth for the first time (see page 167). one more astronomical discovery also he was to make--that of the moon's libration. and then there came one more crushing blow. his eyes became inflamed and painful--the sight of one of them failed, the other soon went; he became totally blind. but this, being a heaven-sent infliction, he could bear with resignation, though it must have been keenly painful to a solitary man of his activity. "alas!" says he, in one of his letters, "your dear friend and servant is totally blind. henceforth this heaven, this universe, which by wonderful observations i had enlarged a hundred and a thousand times beyond the conception of former ages, is shrunk for me into the narrow space which i myself fill in it. so it pleases god; it shall therefore please me also." he was now allowed an amanuensis, and the help of his pupils torricelli, castelli, and viviani, all devotedly attached to him, and torricelli very famous after him. visitors also were permitted, after approval by a jesuit supervisor; and under these circumstances many visited him, among them a man as immortal as himself--john milton, then only twenty-nine, travelling in italy. surely a pathetic incident, this meeting of these two great men--the one already blind, the other destined to become so. no wonder that, as in his old age he dictated his masterpiece, the thoughts of the english poet should run on the blind sage of tuscany, and the reminiscence of their conversation should lend colour to the poem. well, it were tedious to follow the petty annoyances and troubles to which galileo was still subject--how his own son was set to see that no unauthorized procedure took place, and that no heretic visitors were admitted; how it was impossible to get his new book printed till long afterwards; and how one form of illness after another took possession of him. the merciful end came at last, and at the age of seventy-eight he was released from the inquisition. they wanted to deny him burial--they did deny him a monument; they threatened to cart his bones away from florence if his friends attempted one. and so they hoped that he and his work might be forgotten. poor schemers! before the year was out an infant was born in lincolnshire, whose destiny it was to round and complete and carry forward the work of their victim, so that, until man shall cease from the planet, neither the work nor its author shall have need of a monument. * * * * * here might i end, were it not that the same kind of struggle as went on fiercely in the seventeenth century is still smouldering even now. not in astronomy indeed, as then; nor yet in geology, as some fifty years ago; but in biology mainly--perhaps in other subjects. i myself have heard charles darwin spoken of as an atheist and an infidel, the theory of evolution assailed as unscriptural, and the doctrine of the ascent of man from a lower state of being, as opposed to the fall of man from some higher condition, denied as impious and un-christian. men will not learn by the past; still they brandish their feeble weapons against the truths of nature, as if assertions one way or another could alter fact, or make the thing other than it really is. as galileo said before his spirit was broken, "in these and other positions certainly no man doubts but his holiness the pope hath always an absolute power of admitting or condemning them; but it is not in the power of any creature to make them to be true or false, or otherwise than of their own nature and in fact they are." i know nothing of the views of any here present; but i have met educated persons who, while they might laugh at the men who refused to look through a telescope lest they should learn something they did not like, yet also themselves commit the very same folly. i have met persons who utterly refuse to listen to any view concerning the origin of man other than that of a perfect primæval pair in a garden, and i am constrained to say this much: take heed lest some prophet, after having excited your indignation at the follies and bigotry of a bygone generation, does not turn upon you with the sentence, "thou art the man." summary of facts for lecture vi _science before newton_ _dr. gilbert_, of colchester, physician to queen elizabeth, was an excellent experimenter, and made many discoveries in magnetism and electricity. he was contemporary with tycho brahé, and lived from 1540 to 1603. _francis bacon_, lord verulam, 1561-1626, though a brilliant writer, is not specially important as regards science. he was not a scientific man, and his rules for making discoveries, or methods of induction, have never been consciously, nor often indeed unconsciously, followed by discoverers. they are not in fact practical rules at all, though they were so intended. his really strong doctrines are that phenomena must be studied direct, and that variations in the ordinary course of nature must be induced by aid of experiment; but he lacked the scientific instinct for pursuing these great truths into detail and special cases. he sneered at the work and methods of both gilbert and galileo, and rejected the copernican theory as absurd. his literary gifts have conferred on him an artificially high scientific reputation, especially in england; at the same time his writings undoubtedly helped to make popular the idea of there being new methods for investigating nature, and, by insisting on the necessity for freedom from preconceived ideas and opinions, they did much to release men from the bondage of aristotelian authority and scholastic tradition. the greatest name between galileo and newton is that of descartes. _rené descartes_ was born at la haye in touraine, 1596, and died at stockholm in 1650. he did important work in mathematics, physics, anatomy, and philosophy. was greatest as a philosopher and mathematician. at the age of twenty-one he served as a volunteer under prince maurice of nassau, but spent most of his later life in holland. his famous _discourse on method_ appeared at leyden in 1637, and his _principia_ at amsterdam in 1644; great pains being taken to avoid the condemnation of the church. descartes's main scientific achievement was the application of algebra to geometry; his most famous speculation was the "theory of vortices," invented to account for the motion of planets. he also made many discoveries in optics and physiology. his best known immediate pupils were the princess elizabeth of bohemia, and christina, queen of sweden. he founded a distinct school of thought (the cartesian), and was the precursor of the modern mathematical method of investigating science, just as galileo and gilbert were the originators of the modern experimental method. lecture vi descartes and his theory of vortices after the dramatic life we have been considering in the last two lectures, it is well to have a breathing space, to look round on what has been accomplished, and to review the state of scientific thought, before proceeding to the next great era. for we are still in the early morning of scientific discovery: the dawn of the modern period, faintly heralded by copernicus, brought nearer by the work of tycho and kepler, and introduced by the discoveries of galileo--the dawn has occurred, but the sun is not yet visible. it is hidden by the clouds and mists of the long night of ignorance and prejudice. the light is sufficient, indeed, to render these earth-born vapours more visible: it is not sufficient to dispel them. a generation of slow and doubtful progress must pass, before the first ray of sunlight can break through the eastern clouds and the full orb of day itself appear. it is this period of hesitating progress and slow leavening of men's ideas that we have to pass through in this week's lecture. it always happens thus: the assimilation of great and new ideas is always a slow and gradual process: there is no haste either here or in any other department of nature. _die zeit ist unendlich lang._ steadily the forces work, sometimes seeming to accomplish nothing; sometimes even the motion appears retrograde; but in the long run the destined end is reached, and the course, whether of a planet or of men's thoughts about the universe, is permanently altered. then, the controversy was about the _earth's_ place in the universe; now, if there be any controversy of the same kind, it is about _man's_ place in the universe; but the process is the same: a startling statement by a great genius or prophet, general disbelief, and, it may be, an attitude of hostility, gradual acceptance by a few, slow spreading among the many, ending in universal acceptance and faith often as unquestioning and unreasoning as the old state of unfaith had been. now the process is comparatively speedy: twenty years accomplishes a great deal: then it was tediously slow, and a century seemed to accomplish very little. periodical literature may be responsible for some waste of time, but it certainly assists the rapid spread of ideas. the rate with which ideas are assimilated by the general public cannot even now be considered excessive, but how much faster it is than it was a few centuries ago may be illustrated by the attitude of the public to darwinism now, twenty-five years after _the origin of species_, as compared with their attitude to the copernican system a century after _de revolutionibus_. by the way, it is, i know, presumptuous for me to have an opinion, but i cannot hear darwin compared to or mentioned along with newton without a shudder. the stage in which he found biology seems to me far more comparable with the ptolemaic era in astronomy, and he himself to be quite fairly comparable to copernicus. let us proceed to summarize the stage at which the human race had arrived at the epoch with which we are now dealing. the copernican view of the solar system had been stated, restated, fought, and insisted on; a chain of brilliant telescopic discoveries had made it popular and accessible to all men of any intelligence: henceforth it must be left to slowly percolate and sink into the minds of the people. for the nations were waking up now, and were accessible to new ideas. england especially was, in some sort, at the zenith of its glory; or, if not at the zenith, was in that full flush of youth and expectation and hope which is stronger and more prolific of great deeds and thoughts than a maturer period. a common cause against a common and detested enemy had roused in the hearts of englishmen a passion of enthusiasm and patriotism; so that the mean elements of trade, their cheating yard-wands, were forgotten for a time; the armada was defeated, and the nation's true and conscious adult life began. commerce was now no mere struggle for profit and hard bargains; it was full of the spirit of adventure and discovery; a new world had been opened up; who could tell what more remained unexplored? men awoke to the splendour of their inheritance, and away sailed drake and frobisher and raleigh into the lands of the west. for literature, you know what a time it was. the author of _hamlet_ and _othello_ was alive: it is needless to say more. and what about science? the atmosphere of science is a more quiet and less stirring one; it thrives best when the fever of excitement is allayed; it is necessarily a later growth than literature. already, however, our second great man of science was at work in a quiet country town--second in point of time, i mean, roger bacon being the first. dr. gilbert, of colchester, was the second in point of time, and the age was ripening for the time when england was to be honoured with such a galaxy of scientific luminaries--hooke and boyle and newton--as the world had not yet known. yes, the nations were awake. "in all directions," as draper says, "nature was investigated: in all directions new methods of examination were yielding unexpected and beautiful results. on the ruins of its ivy-grown cathedrals ecclesiasticism [or scholasticism], surprised and blinded by the breaking day, sat solemnly blinking at the light and life about it, absorbed in the recollection of the night that had passed, dreaming of new phantoms and delusions in its wished-for return, and vindictively striking its talons at any derisive assailant who incautiously approached too near." of the work of gilbert there is much to say; so there is also of roger bacon, whose life i am by no means sure i did right in omitting. but neither of them had much to do with astronomy, and since it is in astronomy that the most startling progress was during these centuries being made, i have judged it wiser to adhere mainly to the pioneers in this particular department. only for this reason do i pass gilbert with but slight mention. he knew of the copernican theory and thoroughly accepted it (it is convenient to speak of it as the copernican theory, though you know that it had been considerably improved in detail since the first crude statement by copernicus), but he made in it no changes. he was a cultivated scientific man, and an acute experimental philosopher; his main work lay in the domain of magnetism and electricity. the phenomena connected with the mariner's compass had been studied somewhat by roger bacon; and they were now examined still more thoroughly by gilbert, whose treatise _de magnete_, marks the beginning of the science of magnetism. as an appendix to that work he studied the phenomenon of amber, which had been mentioned by thales. he resuscitated this little fact after its burial of 2,200 years, and greatly extended it. he it was who invented the name electricity--i wish it had been a shorter one. mankind invents names much better than do philosophers. what can be better than "heat," "light," "sound"? how favourably they compare with electricity, magnetism, galvanism, electro-magnetism, and magneto-electricity! the only long-established monosyllabic name i know invented by a philosopher is "gas"--an excellent attempt, which ought to be imitated.[12] of lord bacon, who flourished about the same time (a little later), it is necessary to say something, because many persons are under the impression that to him and his _novum organon_ the reawakening of the world, and the overthrow of aristotelian tradition, are mainly due. his influence, however, has been exaggerated. i am not going to enter into a discussion of the _novum organon_, and the mechanical methods which he propounded as certain to evolve truth if patiently pursued; for this is what he thought he was doing--giving to the world an infallible recipe for discovering truth, with which any ordinarily industrious man could make discoveries by means of collection and discrimination of instances. you will take my statement for what it is worth, but i assert this: that many of the methods which bacon lays down are not those which the experience of mankind has found to be serviceable; nor are they such as a scientific man would have thought of devising. true it is that a real love and faculty for science are born in a man, and that to the man of scientific capacity rules of procedure are unnecessary; his own intuition is sufficient, or he has mistaken his vocation,--but that is not my point. it is not that bacon's methods are useless because the best men do not need them; if they had been founded on a careful study of the methods actually employed, though it might be unconsciously employed, by scientific men--as the methods of induction, stated long after by john stuart mill, were founded--then, no doubt, their statement would have been a valuable service and a great thing to accomplish. but they were not this. they are the ideas of a brilliant man of letters, writing in an age when scientific research was almost unknown, about a subject in which he was an amateur. i confess i do not see how he, or john stuart mill, or any one else, writing in that age, could have formulated the true rules of philosophizing; because the materials and information were scarcely to hand. science and its methods were only beginning to grow. no doubt it was a brilliant attempt. no doubt also there are many good and true points in the statement, especially in his insistence on the attitude of free and open candour with which the investigation of nature should be approached. no doubt there was much beauty in his allegories of the errors into which men were apt to fall--the _idola_ of the market-place, of the tribe, of the theatre, and of the den; but all this is literature, and on the solid progress of science may be said to have had little or no effect. descartes's _discourse on method_ was a much more solid production. you will understand that i speak of bacon purely as a scientific man. as a man of letters, as a lawyer, a man of the world, and a statesman, he is beyond any criticism of mine. i speak only of the purely scientific aspect of the _novum organon_. _the essays_ and _the advancement of learning_ are masterly productions; and as a literary man he takes high rank. the over-praise which, in the british isles, has been lavished upon his scientific importance is being followed abroad by what may be an unnecessary amount of detraction. this is always the worst of setting up a man on too high a pinnacle; some one has to undertake the ungrateful task of pulling him down again. justus von liebig addressed himself to this task with some vigour in his _reden und abhandlung_ (leipzig, 1874), where he quotes from bacon a number of suggestions for absurd experimentation.[13] the next paragraph i read, not because i endorse it, but because it is always well to hear both sides of a question. you have probably been long accustomed to read over-estimates of bacon's importance, and extravagant laudation of his writings as making an epoch in science; hear what draper says on the opposite side:--[14] "the more closely we examine the writings of lord bacon, the more unworthy does he seem to have been of the great reputation which has been awarded to him. the popular delusion to which he owes so much originated at a time when the history of science was unknown. they who first brought him into notice knew nothing of the old school of alexandria. this boasted founder of a new philosophy could not comprehend, and would not accept, the greatest of all scientific doctrines when it was plainly set before his eyes. "it has been represented that the invention of the true method of physical science was an amusement of bacon's hours of relaxation from the more laborious studies of law, and duties of a court. "his chief admirers have been persons of a literary turn, who have an idea that scientific discoveries are accomplished by a mechanico-mental operation. bacon never produced any great practical result himself, no great physicist has ever made any use of his method. he has had the same to do with the development of modern science that the inventor of the orrery has had to do with the discovery of the mechanism of the world. of all the important physical discoveries, there is not one which shows that its author made it by the baconian instrument. "newton never seems to have been aware that he was under any obligation to bacon. archimedes, and the alexandrians, and the arabians, and leonardo da vinci did very well before he was born; the discovery of america by columbus and the circumnavigation by magellan can hardly be attributed to him, yet they were the consequences of a truly philosophical reasoning. but the investigation of nature is an affair of genius, not of rules. no man can invent an _organon_ for writing tragedies and epic poems. bacon's system is, in its own terms, an idol of the theatre. it would scarcely guide a man to a solution of the riddle of ælia lælia crispis, or to that of the charade of sir hilary. "few scientific pretenders have made more mistakes than lord bacon. he rejected the copernican system, and spoke insolently of its great author; he undertook to criticize adversely gilbert's treatise _de magnete_; he was occupied in the condemnation of any investigation of final causes, while harvey was deducing the circulation of the blood from aquapendente's discovery of the valves in the veins; he was doubtful whether instruments were of any advantage, while galileo was investigating the heavens with the telescope. ignorant himself of every branch of mathematics, he presumed that they were useless in science but a few years before newton achieved by their aid his immortal discoveries. "it is time that the sacred name of philosophy should be severed from its long connection with that of one who was a pretender in science, a time-serving politician, an insidious lawyer, a corrupt judge, a treacherous friend, a bad man." this seems to me a depreciation as excessive as are the eulogies commonly current. the truth probably lies somewhere between the two extremes. it is unfair to judge bacon's methods by thinking of physical science in its present stage. to realise his position we must think of a subject still in its very early infancy, one in which the advisability of applying experimental methods is still doubted; one which has been studied by means of books and words and discussion of normal instances, instead of by collection and observation of the unusual and irregular, and by experimental production of variety. if we think of a subject still in this infantile and almost pre-scientific stage, bacon's words and formulæ are far from inapplicable; they are, within their limitations, quite necessary and wholesome. a subject in this stage, strange to say, exists,--psychology; now hesitatingly beginning to assume its experimental weapons amid a stifling atmosphere of distrust and suspicion. bacon's lack of the modern scientific instinct must be admitted, but he rendered humanity a powerful service in directing it from books to nature herself, and his genius is indubitable. a judicious account of his life and work is given by prof. adamson, in the _encyclopædia britannica_, and to this article i now refer you. * * * * * who, then, was the man of first magnitude filling up the gap in scientific history between the death of galileo and the maturity of newton? unknown and mysterious are the laws regulating the appearance of genius. we have passed in review a pole, a dane, a german, and an italian,--the great man is now a frenchman, rené descartes, born in touraine, on the 31st of march, 1596. his mother died at his birth; the father was of no importance, save as the owner of some landed property. the boy was reared luxuriously, and inherited a fair fortune. nearly all the men of first rank, you notice, were born well off. genius born to poverty might, indeed, even then achieve name and fame--as we see in the case of kepler--but it was terribly handicapped. handicapped it is still, but far less than of old; and we may hope it will become gradually still less so as enlightenment proceeds, and the tremendous moment of great men to a nation is more clearly and actively perceived. it is possible for genius, when combined with strong character, to overcome all obstacles, and reach the highest eminence, but the struggle must be severe; and the absence of early training and refinement during the receptive years of youth must be a lifelong drawback. descartes had none of these drawbacks; life came easily to him, and, as a consequence perhaps, he never seems to have taken it quite seriously. great movements and stirring events were to him opportunities for the study of men and manners; he was not the man to court persecution, nor to show enthusiasm for a losing or struggling cause. in this, as in many other things, he was imbued with a very modern spirit, a cynical and sceptical spirit, which, to an outside and superficial observer like myself, seems rather rife just now. he was also imbued with a phase of scientific spirit which you sometimes still meet with, though i believe it is passing away, viz. an uncultured absorption in his own pursuits, and some feeling of contempt for classical and literary and æsthetic studies. in politics, art, and history he seems to have had no interest. he was a spectator rather than an actor on the stage of the world; and though he joined the army of that great military commander prince maurice of nassau, he did it not as a man with a cause at heart worth fighting for, but precisely in the spirit in which one of our own gilded youths would volunteer in a similar case, as a good opportunity for frolic and for seeing life. he soon tired of it and withdrew--at first to gay society in paris. here he might naturally have sunk into the gutter with his companions, but for a great mental shock which became the main epoch and turning-point of his life, the crisis which diverted him from frivolity to seriousness. it was a purely intellectual emotion, not excited by anything in the visible or tangible world; nor could it be called conversion in the common acceptation of that term. he tells us that on the 10th of november, 1619, at the age of twenty-four, a brilliant idea flashed upon him--the first idea, namely, of his great and powerful mathematical method, of which i will speak directly; and in the flush of it he foresaw that just as geometers, starting with a few simple and evident propositions or axioms, ascend by a long and intricate ladder of reasoning to propositions more and more abstruse, so it might be possible to ascend from a few data, to all the secrets and facts of the universe, by a process of mathematical reasoning. "comparing the mysteries of nature with the laws of mathematics, he dared to hope that the secrets of both could be unlocked with the same key." that night he lapsed gradually into a state of enthusiasm, in which he saw three dreams or visions, which he interpreted at the time, even before waking, to be revelations from the spirit of truth to direct his future course, as well as to warn him from the sins he had already committed. his account of the dreams is on record, but is not very easy to follow; nor is it likely that a man should be able to convey to others any adequate idea of the deepest spiritual or mental agitation which has shaken him to his foundations. his associates in paris were now abandoned, and he withdrew, after some wanderings, to holland, where he abode the best part of his life and did his real work. even now, however, he took life easily. he recommends idleness as necessary to the production of good mental work. he worked and meditated but a few hours a day: and most of those in bed. he used to think best in bed, he said. the afternoon he devoted to society and recreation. after supper he wrote letters to various persons, all plainly intended for publication, and scrupulously preserved. he kept himself free from care, and was most cautious about his health, regarding himself, no doubt, as a subject of experiment, and wishful to see how long he could prolong his life. at one time he writes to a friend that he shall be seriously disappointed if he does not manage to see 100 years. [illustration: fig. 53.--descartes.] this plan of not over-working himself, and limiting the hours devoted to serious thought, is one that might perhaps advantageously be followed by some over-laborious students of the present day. at any rate it conveys a lesson; for the amount of ground covered by descartes, in a life not very long, is extraordinary. he must, however, have had a singular aptitude for scientific work; and the judicious leaven of selfishness whereby he was able to keep himself free from care and embarrassments must have been a great help to him. and what did his versatile genius accomplish during his fifty-four years of life? in philosophy, using the term as meaning mental or moral philosophy and metaphysics, as opposed to natural philosophy or physics, he takes a very high rank, and it is on this that perhaps his greatest fame rests. (he is the author, you may remember, of the famous aphorism, "_cogito, ergo sum_.") in biology i believe he may be considered almost equally great: certainly he spent a great deal of time in dissecting, and he made out a good deal of what is now known of the structure of the body, and of the theory of vision. he eagerly accepted the doctrine of the circulation of the blood, then being taught by harvey, and was an excellent anatomist. you doubtless know professor huxley's article on descartes in the _lay sermons_, and you perceive in what high estimation he is there held. he originated the hypothesis that animals are automata, for which indeed there is much to be said from some points of view; but he unfortunately believed that they were unconscious and non-sentient automata, and this belief led his disciples into acts of abominable cruelty. professor huxley lectured on this hypothesis and partially upheld it not many years since. the article is included in his volume called _science and culture_. concerning his work in mathematics and physics i can speak with more confidence. he is the author of the cartesian system of algebraic or analytic geometry, which has been so powerful an engine of research, far easier to wield than the old synthetic geometry. without it newton could never have written the _principia_, or made his greatest discoveries. he might indeed have invented it for himself, but it would have consumed some of his life to have brought it to the necessary perfection. the principle of it is the specification of the position of a point in a plane by two numbers, indicating say its distance from two lines of reference in the plane; like the latitude and longitude of a place on the globe. for instance, the two lines of reference might be the bottom edge and the left-hand vertical edge of a wall; then a point on the wall, stated as being for instance 6 feet along and 2 feet up, is precisely determined. these two distances are called co-ordinates; horizontal ones are usually denoted by _x_, and vertical ones by _y_. if, instead of specifying two things, only one statement is made, such as _y_ = 2, it is satisfied by a whole row of points, all the points in a horizontal line 2 feet above the ground. hence _y_ = 2 may be said to represent that straight line, and is called the equation to that straight line. similarly _x_ = 6 represents a vertical straight line 6 feet (or inches or some other unit) from the left-hand edge. if it is asserted that _x_ = 6 and _y_ = 2, only one point can be found to satisfy both conditions, viz. the crossing point of the above two straight lines. suppose an equation such as _x_ = _y_ to be given. this also is satisfied by a row of points, viz. by all those that are equidistant from bottom and left-hand edges. in other words, _x_ = _y_ represents a straight line slanting upwards at 45°. the equation _x_ = 2_y_ represents another straight line with a different angle of slope, and so on. the equation x^2 + y^2 = 36 represents a circle of radius 6. the equation 3x^2 + 4y^2 = 25 represents an ellipse; and in general every algebraic equation that can be written down, provided it involve only two variables, _x_ and _y_, represents some curve in a plane; a curve moreover that can be drawn, or its properties completely investigated without drawing, from the equation. thus algebra is wedded to geometry, and the investigation of geometric relations by means of algebraic equations is called analytical geometry, as opposed to the old euclidian or synthetic mode of treating the subject by reasoning consciously directed to the subject by help of figures. if there be three variables--_x_, _y_, and _z_,--instead of only two, an equation among them represents not a curve in a plane but a surface in space; the three variables corresponding to the three dimensions of space: length, breadth, and thickness. an equation with four variables usually requires space of four dimensions for its geometrical interpretation, and so on. thus geometry can not only be reasoned about in a more mechanical and therefore much easier, manner, but it can be extended into regions of which we have and can have no direct conception, because we are deficient in sense organs for accumulating any kind of experience in connexion with such ideas. [illustration: fig. 54.--the eye diagram. [from descartes' _principia_.] three external points are shown depicted on the retina: the image being appreciated by a representation of the brain.] in physics proper descartes' tract on optics is of considerable historical interest. he treats all the subjects he takes up in an able and original manner. in astronomy he is the author of that famous and long upheld theory, the doctrine of vortices. he regarded space as a plenum full of an all-pervading fluid. certain portions of this fluid were in a state of whirling motion, as in a whirlpool or eddy of water; and each planet had its own eddy, in which it was whirled round and round, as a straw is caught and whirled in a common whirlpool. this idea he works out and elaborates very fully, applying it to the system of the world, and to the explanation of all the motions of the planets. [illustration: fig. 55.--descartes's diagram of vortices, from his _principia_.] this system evidently supplied a void in men's minds, left vacant by the overthrow of the ptolemaic system, and it was rapidly accepted. in the english universities it held for a long time almost undisputed sway; it was in this faith that newton was brought up. something was felt to be necessary to keep the planets moving on their endless round; the _primum mobile_ of ptolemy had been stopped; an angel was sometimes assigned to each planet to carry it round, but though a widely diffused belief, this was a fantastic and not a serious scientific one. descartes's vortices seemed to do exactly what was wanted. it is true they had no connexion with the laws of kepler. i doubt whether he knew about the laws of kepler; he had not much opinion of other people's work; he read very little--found it easier to think. (he travelled through florence once when galileo was at the height of his renown without calling upon or seeing him.) in so far as the motion of a planet was not circular, it had to be accounted for by the jostling and crowding and distortion of the vortices. gravitation he explained by a settling down of bodies toward the centre of each vortex; and cohesion by an absence of relative motion tending to separate particles of matter. he "can imagine no stronger cement." the vortices, as descartes imagined them, are not now believed in. are we then to regard the system as absurd and wholly false? i do not see how we can do this, when to this day philosophers are agreed in believing space to be completely full of fluid, which fluid is certainly capable of vortex motion, and perhaps everywhere does possess that motion. true, the now imagined vortices are not the large whirls of planetary size, they are rather infinitesimal whirls of less than atomic dimensions; still a whirling fluid is believed in to this day, and many are seeking to deduce all the properties of matter (rigidity, elasticity, cohesion gravitation, and the rest) from it. further, although we talk glibly about gravitation and magnetism, and so on, we do not really know what they are. progress is being made, but we do not yet properly know. much, overwhelmingly much, remains to be discovered, and it ill-behoves us to reject any well-founded and long-held theory as utterly and intrinsically false and absurd. the more one gets to know, the more one perceives a kernel of truth even in the most singular statements; and scientific men have learned by experience to be very careful how they lop off any branch of the tree of knowledge, lest as they cut away the dead wood they lose also some green shoot, some healthy bud of unperceived truth. however, it may be admitted that the idea of a cartesian vortex in connexion with the solar system applies, if at all, rather to an earlier--its nebulous--stage, when the whole thing was one great whirl, ready to split or shrink off planetary rings at their appropriate distances. soon after he had written his great work, the _principia mathematica_, and before he printed it, news reached him of the persecution and recantation of galileo. "he seems to have been quite thunderstruck at the tidings," says mr. mahaffy, in his _life of descartes_.[15] "he had started on his scientific journeys with the firm determination to enter into no conflict with the church, and to carry out his system of pure mathematics and physics without ever meddling with matters of faith. he was rudely disillusioned as to the possibility of this severance. he wrote at once--apparently, november 20th, 1633--to mersenne to say he would on no account publish his work--nay, that he had at first resolved to burn all his papers, for that he would never prosecute philosophy at the risk of being censured by his church. 'i could hardly have believed,' he says, 'that an italian, and in favour with the pope as i hear, could be considered criminal for nothing else than for seeking to establish the earth's motion; though i know it has formerly been censured by some cardinals. but i thought i had heard that since then it was constantly being taught, even at rome; and i confess that if the opinion of the earth's movement is false, all the foundations of my philosophy are so also, because it is demonstrated clearly by them. it is so bound up with every part of my treatise that i could not sever it without making the remainder faulty; and although i consider all my conclusions based on very certain and clear demonstrations, i would not for all the world sustain them against the authority of the church.'" ten years later, however, he did publish the book, for he had by this time hit on an ingenious compromise. he formally denied that the earth moved, and only asserted that it was carried along with its water and air in one of those larger motions of the celestial ether which produce the diurnal and annual revolutions of the solar system. so, just as a passenger on the deck of a ship might be called stationary, so was the earth. he gives himself out therefore as a follower of tycho rather than of copernicus, and says if the church won't accept this compromise he must return to the ptolemaic system; but he hopes they won't compel him to do that, seeing that it is manifestly untrue. this elaborate deference to the powers that be did not indeed save the work from being ultimately placed upon the forbidden list by the church, but it saved himself, at any rate, from annoying persecution. he was not, indeed, at all willing to be persecuted, and would no doubt have at once withdrawn anything they wished. i should be sorry to call him a time-server, but he certainly had plenty of that worldly wisdom in which some of his predecessors had been so lamentably deficient. moreover, he was really a sceptic, and cared nothing at all about the church or its dogmas. he knew the church's power, however, and the advisability of standing well with it: he therefore professed himself a catholic, and studiously kept his science and his christianity distinct. in saying that he was a sceptic you must not understand that he was in the least an atheist. very few men are; certainly descartes never thought of being one. the term is indeed ludicrously inapplicable to him, for a great part of his philosophy is occupied with what he considers a rigorous proof of the existence of the deity. at the age of fifty-three he was sent for to stockholm by christina, queen of sweden, a young lady enthusiastically devoted to study of all kinds and determined to surround her court with all that was most famous in literature and science. thither, after hesitation, descartes went. he greatly liked royalty, but he dreaded the cold climate. born in touraine, a swedish winter was peculiarly trying to him, especially as the energetic queen would have lessons given her at five o'clock in the morning. she intended to treat him well, and was immensely taken with him; but this getting up at five o'clock on a november morning, to a man accustomed all his life to lie in bed till eleven, was a cruel hardship. he was too much of a courtier, however, to murmur, and the early morning audience continued. his health began to break down: he thought of retreating, but suddenly he gave way and became delirious. the queen's physician attended him, and of course wanted to bleed him. this, knowing all he knew of physiology, sent him furious, and they could do nothing with him. after some days he became quiet, was bled twice, and gradually sank, discoursing with great calmness on his approaching death, and duly fortified with all the rites of the catholic church. his general method of research was as nearly as possible a purely deductive one:--_i.e._, after the manner of euclid he starts with a few simple principles, and then, by a chain of reasoning, endeavours to deduce from them their consequences, and so to build up bit by bit an edifice of connected knowledge. in this he was the precursor of newton. this method, when rigorously pursued, is the most powerful and satisfactory of all, and results in an ordered province of science far superior to the fragmentary conquests of experiment. but few indeed are the men who can handle it safely and satisfactorily: and none without continual appeals to experiment for verification. it was through not perceiving the necessity for verification that he erred. his importance to science lies not so much in what he actually discovered as in his anticipation of the right conditions for the solution of problems in physical science. he in fact made the discovery that nature could after all be interrogated mathematically--a fact that was in great danger of remaining unknown. for, observe, that the mathematical study of nature, the discovery of truth with a piece of paper and a pen, has a perilous similarity at first sight to the straw-thrashing subtleties of the greeks, whose methods of investigating nature by discussing the meaning of words and the usage of language and the necessities of thought, had proved to be so futile and unproductive. a reaction had set in, led by galileo, gilbert, and the whole modern school of experimental philosophers, lasting down to the present day:--men who teach that the only right way of investigating nature is by experiment and observation. it is indeed a very right and an absolutely necessary way; but it is not the only way. a foundation of experimental fact there must be; but upon this a great structure of theoretical deduction can be based, all rigidly connected together by pure reasoning, and all necessarily as true as the premises, provided no mistake is made. to guard against the possibility of mistake and oversight, especially oversight, all conclusions must sooner or later be brought to the test of experiment; and if disagreeing therewith, the theory itself must be re-examined, and the flaw discovered, or else the theory must be abandoned. of this grand method, quite different from the gropings in the dark of kepler--this method, which, in combination with experiment, has made science what it now is--this which in the hands of newton was to lead to such stupendous results, we owe the beginning and early stages to rené descartes. summary of facts for lectures vii and viii otto guericke 1602-1686 hon. robert boyle 1626-1691 huyghens 1629-1695 christopher wren 1632-1723 robert hooke 1635-1702 newton 1642-1727 edmund halley 1656-1742 james bradley 1692-1762 _chronology of newton's life._ isaac newton was born at woolsthorpe, near grantham, lincolnshire, on christmas day, 1642. his father, a small freehold farmer, also named isaac, died before his birth. his mother, _née_ hannah ayscough, in two years married a mr. smith, rector of north witham, but was again left a widow in 1656. his uncle, w. ayscough, was rector of a near parish and a graduate of trinity college, cambridge. at the age of fifteen isaac was removed from school at grantham to be made a farmer of, but as it seemed he would not make a good one his uncle arranged for him to return to school and thence to cambridge, where he entered trinity college as a sub-sizar in 1661. studied descartes's geometry. found out a method of infinite series in 1665, and began the invention of fluxions. in the same year and the next he was driven from cambridge by the plague. in 1666, at woolsthorpe, the apple fell. in 1667 he was elected a fellow of his college, and in 1669 was specially noted as possessing an unparalleled genius by dr. barrow, first lucasian professor of mathematics. the same year dr. barrow retired from his chair in favour of newton, who was thus elected at the age of twenty-six. he lectured first on optics with great success. early in 1672 he was elected a fellow of the royal society, and communicated his researches in optics, his reflecting telescope, and his discovery of the compound nature of white light. annoying controversies arose; but he nevertheless contributed a good many other most important papers in optics, including observations in diffraction, and colours of thin plates. he also invented the modern sextant. in 1672 a letter from paris was read at the royal society concerning a new and accurate determination of the size of the earth by picard. when newton heard of it he began the _principia_, working in silence. in 1684 arose a discussion between wren, hooke, and halley concerning the law of inverse square as applied to gravity and the path it would cause the planets to describe. hooke asserted that he had a solution, but he would not produce it. after waiting some time for it halley went to cambridge to consult newton on the subject, and thus discovered the existence of the first part of the _principia_, wherein all this and much more was thoroughly worked out. on his representations to the royal society the manuscript was asked for, and when complete was printed and published in 1687 at halley's expense. while it was being completed newton and seven others were sent to uphold the dignity of the university, before the court of high commission and judge jeffreys, against a high-handed action of james ii. in 1682 he was sent to parliament, and was present at the coronation of william and mary. made friends with locke. in 1694 montague, lord halifax, made him warden, and in 1697 master, of the mint. whiston succeeded him as lucasian professor. in 1693 the method of fluxions was published. in 1703 newton was made president of the royal society, and held the office to the end of his life. in 1705 he was knighted by anne. in 1713 cotes helped him to bring out a new edition of the _principia_, completed as we now have it. on the 20th of march 1727, he died: having lived from charles i. to george ii. the laws of motion, discovered by galileo, stated by newton. _law 1._--if no force acts on a body in motion, it continues to move uniformly in a straight line. _law 2._--if force acts on a body, it produces a change of motion proportional to the force and in the same direction. _law 3._--when one body exerts force on another, that other reacts with equal force upon the one. lecture vii sir isaac newton the little hamlet of woolsthorpe lies close to the village of colsterworth, about six miles south of grantham, in the county of lincoln. in the manor house of woolsthorpe, on christmas day, 1642, was born to a widowed mother a sickly infant who seemed not long for this world. two women who were sent to north witham to get some medicine for him scarcely expected to find him alive on their return. however, the child lived, became fairly robust, and was named isaac, after his father. what sort of a man this father was we do not know. he was what we may call a yeoman, that most wholesome and natural of all classes. he owned the soil he tilled, and his little estate had already been in the family for some hundred years. he was thirty-six when he died, and had only been married a few months. of the mother, unfortunately, we know almost as little. we hear that she was recommended by a parishioner to the rev. barnabas smith, an old bachelor in search of a wife, as "the widow newton--an extraordinary good woman:" and so i expect she was, a thoroughly sensible, practical, homely, industrious, middle-class, mill-on-the-floss sort of woman. however, on her second marriage she went to live at north witham, and her mother, old mrs. ayscough, came to superintend the farm at woolsthorpe, and take care of young isaac. by her second marriage his mother acquired another piece of land, which she settled on her first son; so isaac found himself heir to two little properties, bringing in a rental of about £80 a year. [illustration: fig. 56.--manor-house of woolsthorpe.] he had been sent to a couple of village schools to acquire the ordinary accomplishments taught at those places, and for three years to the grammar school at grantham, then conducted by an old gentleman named mr. stokes. he had not been very industrious at school, nor did he feel keenly the fascinations of the latin grammar, for he tells us that he was the last boy in the lowest class but one. he used to pay much more attention to the construction of kites and windmills and waterwheels, all of which he made to work very well. he also used to tie paper lanterns to the tail of his kite, so as to make the country folk fancy they saw a comet, and in general to disport himself as a boy should. it so happened, however, that he succeeded in thrashing, in fair fight, a bigger boy who was higher in the school, and who had given him a kick. his success awakened a spirit of emulation in other things than boxing, and young newton speedily rose to be top of the school. under these circumstances, at the age of fifteen, his mother, who had now returned to woolsthorpe, which had been rebuilt, thought it was time to train him for the management of his land, and to make a farmer and grazier of him. the boy was doubtless glad to get away from school, but he did not take kindly to the farm--especially not to the marketing at grantham. he and an old servant were sent to grantham every week to buy and sell produce, but young isaac used to leave his old mentor to do all the business, and himself retire to an attic in the house he had lodged in when at school, and there bury himself in books. after a time he didn't even go through the farce of visiting grantham at all; but stopped on the road and sat under a hedge, reading or making some model, until his companion returned. we hear of him now in the great storm of 1658, the storm on the day cromwell died, measuring the force of the wind by seeing how far he could jump with it and against it. he also made a water-clock and set it up in the house at grantham, where it kept fairly good time so long as he was in the neighbourhood to look after it occasionally. at his own home he made a couple of sundials on the side of the wall (he began by marking the position of the sun by the shadow of a peg driven into the wall, but this gradually developed into a regular dial) one of which remained of use for some time; and was still to be seen in the same place during the first half of the present century, only with the gnomon gone. in 1844 the stone on which it was carved was carefully extracted and presented to the royal society, who preserve it in their library. the letters wton roughly carved on it are barely visible. all these pursuits must have been rather trying to his poor mother, and she probably complained to her brother, the rector of burton coggles: at any rate this gentleman found master newton one morning under a hedge when he ought to have been farming. but as he found him working away at mathematics, like a wise man he persuaded his sister to send the boy back to school for a short time, and then to cambridge. on the day of his finally leaving school old mr. stokes assembled the boys, made them a speech in praise of newton's character and ability, and then dismissed him to cambridge. at trinity college a new world opened out before the country-bred lad. he knew his classics passably, but of mathematics and science he was ignorant, except through the smatterings he had picked up for himself. he devoured a book on logic, and another on kepler's optics, so fast that his attendance at lectures on these subjects became unnecessary. he also got hold of a euclid and of descartes's geometry. the euclid seemed childishly easy, and was thrown aside, but the descartes baffled him for a time. however, he set to it again and again and before long mastered it. he threw himself heart and soul into mathematics, and very soon made some remarkable discoveries. first he discovered the binomial theorem: familiar now to all who have done any algebra, unintelligible to others, and therefore i say nothing about it. by the age of twenty-one or two he had begun his great mathematical discovery of infinite series and fluxions--now known by the name of the differential calculus. he wrote these things out and must have been quite absorbed in them, but it never seems to have occurred to him to publish them or tell any one about them. in 1664 he noticed some halos round the moon, and, as his manner was, he measured their angles--the small ones 3 and 5 degrees each, the larger one 22°·35. later he gave their theory. small coloured halos round the moon are often seen, and are said to be a sign of rain. they are produced by the action of minute globules of water or cloud particles upon light, and are brightest when the particles are nearly equal in size. they are not like the rainbow, every part of which is due to light that has entered a raindrop, and been refracted and reflected with prismatic separation of colours; a halo is caused by particles so small as to be almost comparable with the size of waves of light, in a way which is explained in optics under the head "diffraction." it may be easily imitated by dusting an ordinary piece of window-glass over with lycopodium, placing a candle near it, and then looking at the candle-flame through the dusty glass from a fair distance. or you may look at the image of a candle in a dusted looking-glass. lycopodium dust is specially suitable, for its granules are remarkably equal in size. the large halo, more rarely seen, of angular radius 22°·35, is due to another cause again, and is a prismatic effect, although it exhibits hardly any colour. the angle 22-1/2° is characteristic of refraction in crystals with angles of 60° and refractive index about the same as water; in other words this halo is caused by ice crystals in the higher regions of the atmosphere. he also the same year observed a comet, and sat up so late watching it that he made himself ill. by the end of the year he was elected to a scholarship and took his b.a. degree. the order of merit for that year never existed or has not been kept. it would have been interesting, not as a testimony to newton, but to the sense or non-sense of the examiners. the oldest professorship of mathematics at the university of cambridge, the lucasian, had not then been long founded, and its first occupant was dr. isaac barrow, an eminent mathematician, and a kind old man. with him newton made good friends, and was helpful in preparing a treatise on optics for the press. his help is acknowledged by dr. barrow in the preface, which states that he had corrected several errors and made some capital additions of his own. thus we see that, although the chief part of his time was devoted to mathematics, his attention was already directed to both optics and astronomy. (kepler, descartes, galileo, all combined some optics with astronomy. tycho and the old ones combined alchemy; newton dabbled in this also.) newton reached the age of twenty-three in 1665, the year of the great plague. the plague broke out in cambridge as well as in london, and the whole college was sent down. newton went back to woolsthorpe, his mind teeming with ideas, and spent the rest of this year and part of the next in quiet pondering. somehow or other he had got hold of the notion of centrifugal force. it was six years before huyghens discovered and published the laws of centrifugal force, but in some quiet way of his own newton knew about it and applied the idea to the motion of the planets. we can almost follow the course of his thoughts as he brooded and meditated on the great problem which had taxed so many previous thinkers,--what makes the planets move round the sun? kepler had discovered how they moved, but why did they so move, what urged them? even the "how" took a long time--all the time of the greeks, through ptolemy, the arabs, copernicus, tycho: circular motion, epicycles, and excentrics had been the prevailing theory. kepler, with his marvellous industry, had wrested from tycho's observations the secret of their orbits. they moved in ellipses with the sun in one focus. their rate of description of area, not their speed, was uniform and proportional to time. yes, and a third law, a mysterious law of unintelligible import, had also yielded itself to his penetrating industry--a law the discovery of which had given him the keenest delight, and excited an outburst of rapture--viz. that there was a relation between the distances and the periodic times of the several planets. the cubes of the distances were proportional to the squares of the times for the whole system. this law, first found true for the six primary planets, he had also extended, after galileo's discovery, to the four secondary planets, or satellites of jupiter (p. 81). but all this was working in the dark--it was only the first step--this empirical discovery of facts; the facts were so, but how came they so? what made the planets move in this particular way? descartes's vortices was an attempt, a poor and imperfect attempt, at an explanation. it had been hailed and adopted throughout europe for want of a better, but it did not satisfy newton. no, it proceeded on a wrong tack, and kepler had proceeded on a wrong tack in imagining spokes or rays sticking out from the sun and driving the planets round like a piece of mechanism or mill work. for, note that all these theories are based on a wrong idea--the idea, viz., that some force is necessary to maintain a body in motion. but this was contrary to the laws of motion as discovered by galileo. you know that during his last years of blind helplessness at arcetri, galileo had pondered and written much on the laws of motion, the foundation of mechanics. in his early youth, at pisa, he had been similarly occupied; he had discovered the pendulum, he had refuted the aristotelians by dropping weights from the leaning tower (which we must rejoice that no earthquake has yet injured), and he had returned to mechanics at intervals all his life; and now, when his eyes were useless for astronomy, when the outer world has become to him only a prison to be broken by death, he returns once more to the laws of motion, and produces the most solid and substantial work of his life. for this is galileo's main glory--not his brilliant exposition of the copernican system, not his flashes of wit at the expense of a moribund philosophy, not his experiments on floating bodies, not even his telescope and astronomical discoveries--though these are the most taking and dazzling at first sight. no; his main glory and title to immortality consists in this, that he first laid the foundation of mechanics on a firm and secure basis of experiment, reasoning, and observation. he first discovered the true laws of motion. i said little of this achievement in my lecture on him; for the work was written towards the end of his life, and i had no time then. but i knew i should have to return to it before we came to newton, and here we are. you may wonder how the work got published when so many of his manuscripts were destroyed. horrible to say, galileo's own son destroyed a great bundle of his father's manuscripts, thinking, no doubt, thereby to save his own soul. this book on mechanics was not burnt, however. the fact is it was rescued by one or other of his pupils, toricelli or viviani, who were allowed to visit him in his last two or three years; it was kept by them for some time, and then published surreptitiously in holland. not that there is anything in it bearing in any visible way on any theological controversy; but it is unlikely that the inquisition would have suffered it to pass notwithstanding. i have appended to the summary preceding this lecture (p. 160) the three axioms or laws of motion discovered by galileo. they are stated by newton with unexampled clearness and accuracy, and are hence known as newton's laws, but they are based on galileo's work. the first is the simplest; though ignorance of it gave the ancients a deal of trouble. it is simply a statement that force is needed to change the motion of a body; _i.e._ that if no force act on a body it will continue to move uniformly both in speed and direction--in other words, steadily, in a straight line. the old idea had been that some force was needed to maintain motion. on the contrary, the first law asserts, some force is needed to destroy it. leave a body alone, free from all friction or other retarding forces, and it will go on for ever. the planetary motion through empty space therefore wants no keeping up; it is not the motion that demands a force to maintain it, it is the curvature of the path that needs a force to produce it continually. the motion of a planet is approximately uniform so far as speed is concerned, but it is not constant in direction; it is nearly a circle. the real force needed is not a propelling but a deflecting force. the second law asserts that when a force acts, the motion changes, either in speed or in direction, or both, at a pace proportional to the magnitude of the force, and in the same direction as that in which the force acts. now since it is almost solely in direction that planetary motion alters, a deflecting force only is needed; a force at right angles to the direction of motion, a force normal to the path. considering the motion as circular, a force along the radius, a radial or centripetal force, must be acting continually. whirl a weight round and round by a bit of elastic, the elastic is stretched; whirl it faster, it is stretched more. the moving mass pulls at the elastic--that is its centrifugal force; the hand at the centre pulls also--that is centripetal force. the third law asserts that these two forces are equal, and together constitute the tension in the elastic. it is impossible to have one force alone, there must be a pair. you can't push hard against a body that offers no resistance. whatever force you exert upon a body, with that same force the body must react upon you. action and reaction are always equal and opposite. sometimes an absurd difficulty is felt with respect to this, even by engineers. they say, "if the cart pulls against the horse with precisely the same force as the horse pulls the cart, why should the cart move?" why on earth not? the cart moves because the horse pulls it, and because nothing else is pulling it back. "yes," they say, "the cart is pulling back." but what is it pulling back? not itself, surely? "no, the horse." yes, certainly the cart is pulling at the horse; if the cart offered no resistance what would be the good of the horse? that is what he is for, to overcome the pull-back of the cart; but nothing is pulling the cart back (except, of course, a little friction), and the horse is pulling it forward, hence it goes forward. there is no puzzle at all when once you realise that there are two bodies and two forces acting, and that one force acts on each body.[16] if, indeed, two balanced forces acted on one body that would be in equilibrium, but the two equal forces contemplated in the third law act on two different bodies, and neither is in equilibrium. so much for the third law, which is extremely simple, though it has extraordinarily far-reaching consequences, and when combined with a denial of "action at a distance," is precisely the principle of the conservation of energy. attempts at perpetual motion may all be regarded as attempts to get round this "third law." [illustration: fig. 57.] on the subject of the _second_ law a great deal more has to be said before it can be in any proper sense even partially appreciated, but a complete discussion of it would involve a treatise on mechanics. it is _the_ law of mechanics. one aspect of it we must attend to now in order to deal with the motion of the planets, and that is the fact that the change of motion of a body depends solely and simply on the force acting, and not at all upon what the body happens to be doing at the time it acts. it may be stationary, or it may be moving in any direction; that makes no difference. thus, referring back to the summary preceding lecture iv, it is there stated that a dropped body falls 16 feet in the first second, that in two seconds it falls 64 feet, and so on, in proportion to the square of the time. so also will it be the case with a thrown body, but the drop must be reckoned from its line of motion--the straight line which, but for gravity, it would describe. thus a stone thrown from _o_ with the velocity _oa_ would in one second find itself at _a_, in two seconds at _b_, in three seconds at _c_, and so on, in accordance with the first law of motion, if no force acted. but if gravity acts it will have fallen 16 feet by the time it would have got to _a_, and so will find itself at _p_. in two seconds it will be at _q_, having fallen a vertical height of 64 feet; in three seconds it will be at _r_, 144 feet below _c_; and so on. its actual path will be a curve, which in this case is a parabola. (fig. 57.) if a cannon is pointed horizontally over a level plain, the cannon ball will be just as much affected by gravity as if it were dropped, and so will strike the plain at the same instant as another which was simply dropped where it started. one ball may have gone a mile and the other only dropped a hundred feet or so, but the time needed by both for the vertical drop will be the same. the horizontal motion of one is an extra, and is due to the powder. as a matter of fact the path of a projectile in vacuo is only approximately a parabola. it is instructive to remember that it is really an ellipse with one focus very distant, but not at infinity. one of its foci is the centre of the earth. a projectile is really a minute satellite of the earth's, and in vacuo it accurately obeys all kepler's laws. it happens not to be able to complete its orbit, because it was started inconveniently close to the earth, whose bulk gets in its way; but in that respect the earth is to be reckoned as a gratuitous obstruction, like a target, but a target that differs from most targets in being hard to miss. [illustration: fig. 58.] now consider circular motion in the same way, say a ball whirled round by a string. (fig. 58.) attending to the body at _o_, it is for an instant moving towards _a_, and if no force acted it would get to _a_ in a time which for brevity we may call a second. but a force, the pull of the string, is continually drawing it towards _s_, and so it really finds itself at _p_, having described the circular arc _op_, which may be considered to be compounded of, and analyzable into the rectilinear motion _oa_ and the drop _ap_. at _p_ it is for an instant moving towards _b_, and the same process therefore carries it to _q_; in the third second it gets to _r_; and so on: always falling, so to speak, from its natural rectilinear path, towards the centre, but never getting any nearer to the centre. the force with which it has thus to be constantly pulled in towards the centre, or, which is the same thing, the force with which it is tugging at whatever constraint it is that holds it in, is _mv^2/r_; where _m_ is the mass of the particle, _v_ its velocity, and _r_ the radius of its circle of movement. this is the formula first given by huyghens for centrifugal force. we shall find it convenient to express it in terms of the time of one revolution, say _t_. it is easily done, since plainly t = circumference/speed = _2[pi]r/v_; so the above expression for centrifugal force becomes _4[pi]^2mr/t^2_. as to the fall of the body towards the centre every microscopic unit of time, it is easily reckoned. for by euclid iii. 36, and fig. 58, _ap.aa' = ao^2_. take _a_ very near _o_, then _oa = vt_, and _aa' = 2r_; so _ap = v^2t^2/2r = 2[pi]^2r t^2/t^2_; or the fall per second is _2[pi]^2r/t^2_, _r_ being its distance from the centre, and _t_ its time of going once round. in the case of the moon for instance, _r_ is 60 earth radii; more exactly 60·2; and _t_ is a lunar month, or more precisely 27 days, 7 hours, 43 minutes, and 11-1/2 seconds. hence the moon's deflection from the tangential or rectilinear path every minute comes out as very closely 16 feet (the true size of the earth being used). returning now to the case of a small body revolving round a big one, and assuming a force directly proportional to the mass of both bodies, and inversely proportional to the square of the distance between them: _i.e._ assuming the known force of gravity, it is _v mm/r^2_ where _v_ is a constant, called the gravitation constant, to be determined by experiment. if this is the centripetal force pulling a planet or satellite in, it must be equal to the centrifugal force of this latter, viz. (see above). _4[pi]^2mr/t^2 equate the two together, and at once we get _r^3/t^2 = v/4[pi]^2m;_ or, in words, the cube of the distance divided by the square of the periodic time for every planet or satellite of the system under consideration, will be constant and proportional to the mass of the central body. this is kepler's third law, with a notable addition. it is stated above for circular motion only, so as to avoid geometrical difficulties, but even so it is very instructive. the reason of the proportion between _r^3_ and _t^2_ is at once manifest; and as soon as the constant _v_ became known, _the mass of the central body_, the sun in the case of a planet, the earth in the case of the moon, jupiter in the case of his satellites, was at once determined. newton's reasoning at this time might, however, be better displayed perhaps by altering the order of the steps a little, as thus:-the centrifugal force of a body is proportional to _r^3/t^2_, but by kepler's third law _r^3/t^2_ is constant for all the planets, reckoning _r_ from the sun. hence the centripetal force needed to hold in all the planets will be a single force emanating from the sun and varying inversely with the square of the distance from that body. such a force is at once necessary and sufficient. such a force would explain the motion of the planets. but then all this proceeds on a wrong assumption--that the planetary motion is circular. will it hold for elliptic orbits? will an inverse square law of force keep a body moving in an elliptic orbit about the sun in one focus? this is a far more difficult question. newton solved it, but i do not believe that even he could have solved it, except that he had at his disposal two mathematical engines of great power--the cartesian method of treating geometry, and his own method of fluxions. one can explain the elliptic motion now mathematically, but hardly otherwise; and i must be content to state that the double fact is true--viz., that an inverse square law will move the body in an ellipse or other conic section with the sun in one focus, and that if a body so moves it _must_ be acted on by an inverse square law. [illustration: fig. 59.] this then is the meaning of the first and third laws of kepler. what about the second? what is the meaning of the equable description of areas? well, that rigorously proves that a planet is acted on by a force directed to the centre about which the rate of description of areas is equable. it proves, in fact, that the sun is the attracting body, and that no other force acts. for first of all if the first law of motion is obeyed, _i.e._ if no force acts, and if the path be equally subdivided to represent equal times, and straight lines be drawn from the divisions to any point whatever, all these areas thus enclosed will be equal, because they are triangles on equal base and of the same height (euclid, i). see fig. 59; _s_ being any point whatever, and _a_, _b_, _c_, successive positions of a body. now at each of the successive instants let the body receive a sudden blow in the direction of that same point _s_, sufficient to carry it from _a_ to _d_ in the same time as it would have got to _b_ if left alone. the result will be that there will be a compromise, and it will really arrive at _p_, travelling along the diagonal of the parallelogram _ap_. the area its radius vector sweeps out is therefore _sap_, instead of what it would have been, _sab_. but then these two areas are equal, because they are triangles on the same base _as_, and between the same parallels _bp_, _as_; for by the parallelogram law _bp_ is parallel to _ad_. hence the area that would have been described is described, and as all the areas were equal in the case of no force, they remain equal when the body receives a blow at the end of every equal interval of time, _provided_ that every blow is actually directed to _s_, the point to which radii vectores are drawn. [illustration: fig. 60.] [illustration: fig. 61.] it is instructive to see that it does not hold if the blow is any otherwise directed; for instance, as in fig. 61, when the blow is along _ae_, the body finds itself at _p_ at the end of the second interval, but the area _sap_ is by no means equal to _sab_, and therefore not equal to _soa_, the area swept out in the first interval. in order to modify fig. 60 so as to represent continuous motion and steady forces, we have to take the sides of the polygon _oapq_, &c., very numerous and very small; in the limit, infinitely numerous and infinitely small. the path then becomes a curve, and the series of blows becomes a steady force directed towards _s_. about whatever point therefore the rate of description of areas is uniform, that point and no other must be the centre of all the force there is. if there be no force, as in fig. 59, well and good, but if there be any force however small not directed towards _s_, then the rate of description of areas about _s_ cannot be uniform. kepler, however, says that the rate of description of areas of each planet about the sun is, by tycho's observations, uniform; hence the sun is the centre of all the force that acts on them, and there is no other force, not even friction. that is the moral of kepler's second law. we may also see from it that gravity does not travel like light, so as to take time on its journey from sun to planet; for, if it did, there would be a sort of aberration, and the force on its arrival could no longer be accurately directed to the centre of the sun. (see _nature_, vol. xlvi., p. 497.) it is a matter for accuracy of observation, therefore, to decide whether the minutest trace of such deviation can be detected, _i.e._ within what limits of accuracy kepler's second law is now known to be obeyed. i will content myself by saying that the limits are extremely narrow. [reference may be made also to p. 208.] thus then it became clear to newton that the whole solar system depended on a central force emanating from the sun, and varying inversely with the square of the distance from him: for by that hypothesis all the laws of kepler concerning these motions were completely accounted for; and, in fact, the laws necessitated the hypothesis and established it as a theory. similarly the satellites of jupiter were controlled by a force emanating from jupiter and varying according to the same law. and again our moon must be controlled by a force from the earth, decreasing with the distance according to the same law. grant this hypothetical attracting force pulling the planets towards the sun, pulling the moon towards the earth, and the whole mechanism of the solar system is beautifully explained. if only one could be sure there was such a force! it was one thing to calculate out what the effects of such a force would be: it was another to be able to put one's finger upon it and say, this is the force that actually exists and is known to exist. we must picture him meditating in his garden on this want--an attractive force towards the earth. if only such an attractive force pulling down bodies to the earth existed. an apple falls from a tree. why, it does exist! there is gravitation, common gravity that makes bodies fall and gives them their weight. wanted, a force tending towards the centre of the earth. it is to hand! it is common old gravity that had been known so long, that was perfectly familiar to galileo, and probably to archimedes. gravity that regulates the motion of projectiles. why should it only pull stones and apples? why should it not reach as high as the moon? why should it not be the gravitation of the sun that is the central force acting on all the planets? surely the secret of the universe is discovered! but, wait a bit; is it discovered? is this force of gravity sufficient for the purpose? it must vary inversely with the square of the distance from the centre of the earth. how far is the moon away? sixty earth's radii. hence the force of gravity at the moon's distance can only be 1/3600 of what it is on the earth's surface. so, instead of pulling it 16 ft. per second, it should pull it 16/3600 ft. per second, or 16 ft. a minute.[17] how can one decide whether such a force is able to pull the moon the actual amount required? to newton this would seem only like a sum in arithmetic. out with a pencil and paper and reckon how much the moon falls toward the earth in every second of its motion. is it 16/3600? that is what it ought to be: but is it? the size of the earth comes into the calculation. sixty miles make a degree, 360 degrees a circumference. this gives as the earth's diameter 6,873 miles; work it out. the answer is not 16 feet a minute, it is 13·9 feet. surely a mistake of calculation? no, it is no mistake: there is something wrong in the theory, gravity is too strong. instead of falling toward the earth 5-1/3 hundredths of an inch every second, as it would under gravity, the moon only falls 4-2/3 hundredths of an inch per second. with such a discovery in his grasp at the age of twenty-three he is disappointed--the figures do not agree, and he cannot make them agree. either gravity is not the force in action, or else something interferes with it. possibly, gravity does part of the work, and the vortices of descartes interfere with it. he must abandon the fascinating idea for the time. in his own words, "he laid aside at that time any further thought of the matter." so far as is known, he never mentioned his disappointment to a soul. he might, perhaps, if he had been at cambridge, but he was a shy and solitary youth, and just as likely he might not. up in lincolnshire, in the seventeenth century, who was there for him to consult? true, he might have rushed into premature publication, after our nineteenth century fashion, but that was not his method. publication never seemed to have occurred to him. his reticence now is noteworthy, but later on it is perfectly astonishing. he is so absorbed in making discoveries that he actually has to be reminded to tell any one about them, and some one else always has to see to the printing and publishing for him. i have entered thus fully into what i conjecture to be the stages of this early discovery of the law of gravitation, as applicable to the heavenly bodies, because it is frequently and commonly misunderstood. it is sometimes thought that he discovered the force of gravity; i hope i have made it clear that he did no such thing. every educated man long before his time, if asked why bodies fell, would reply just as glibly as they do now, "because the earth attracts them," or "because of the force of gravity." his discovery was that the motions of the solar system were due to the action of a central force, directed to the body at the centre of the system, and varying inversely with the square of the distance from it. this discovery was based upon kepler's laws, and was clear and certain. it might have been published had he so chosen. but he did not like hypothetical and unknown forces; he tried to see whether the known force of gravity would serve. this discovery at that time he failed to make, owing to a wrong numerical datum. the size of the earth he only knew from the common doctrine of sailors that 60 miles make a degree; and that threw him out. instead of falling 16 feet a minute, as it ought under gravity, it only fell 13·9 feet, so he abandoned the idea. we do not find that he returned to it for sixteen years. lecture viii newton and the law of gravitation we left newton at the age of twenty-three on the verge of discovering the mechanism of the solar system, deterred therefrom only by an error in the then imagined size of the earth. he had proved from kepler's laws that a centripetal force directed to the sun, and varying as the inverse square of the distance from that body, would account for the observed planetary motions, and that a similar force directed to the earth would account for the lunar motion; and it had struck him that this force might be the very same as the familiar force of gravitation which gave to bodies their weight: but in attempting a numerical verification of this idea in the case of the moon he was led by the then received notion that sixty miles made a degree on the earth's surface into an erroneous estimate of the size of the moon's orbit. being thus baffled in obtaining such verification, he laid the matter aside for a time. the anecdote of the apple we learn from voltaire, who had it from newton's favourite niece, who with her husband lived and kept house for him all his later life. it is very like one of those anecdotes which are easily invented and believed in, and very often turn out on scrutiny to have no foundation. fortunately this anecdote is well authenticated, and moreover is intrinsically probable; i say fortunately, because it is always painful to have to give up these child-learnt anecdotes, like alfred and the cakes and so on. this anecdote of the apple we need not resign. the tree was blown down in 1820 and part of its wood is preserved. i have mentioned voltaire in connection with newton's philosophy. this acute critic at a later stage did a good deal to popularise it throughout europe and to overturn that of his own countryman descartes. cambridge rapidly became newtonian, but oxford remained cartesian for fifty years or more. it is curious what little hold science and mathematics have ever secured in the older and more ecclesiastical university. the pride of possessing newton has however no doubt been the main stimulus to the special pursuits of cambridge. he now began to turn his attention to optics, and, as was usual with him, his whole mind became absorbed in this subject as if nothing else had ever occupied him. his cash-book for this time has been discovered, and the entries show that he is buying prisms and lenses and polishing powder at the beginning of 1667. he was anxious to improve telescopes by making more perfect lenses than had ever been used before. accordingly he calculated out their proper curves, just as descartes had also done, and then proceeded to grind them as near as he could to those figures. but the images did not please him; they were always blurred and rather indistinct. at length, it struck him that perhaps it was not the lenses but the light which was at fault. perhaps light was so composed that it _could_ not be focused accurately to a sharp and definite point. perhaps the law of refraction was not quite accurate, but only an approximation. so he bought a prism to try the law. he let in sunlight through a small round hole in a window shutter, inserted the prism in the light, and received the deflected beam on a white screen; turning the prism about till it was deviated as little as possible. the patch on the screen was not a round disk, as it would have been without the prism, but was an elongated oval and was coloured at its extremities. evidently refraction was not a simple geometrical deflection of a ray, there was a spreading out as well. [illustration: fig. 63.--a prism not only _deviates_ a beam of sunlight, but also spreads it out or _disperses_ it.] why did the image thus spread out? if it were due to irregularities in the glass a second prism should rather increase them, but a second prism when held in appropriate position was able to neutralise the dispersion and to reproduce the simple round white spot without deviation. evidently the spreading out of the beam was connected in some definite way with its refraction. could it be that the light particles after passing through the prism travelled in variously curved lines, as spinning racquet balls do? to examine this he measured the length of the oval patch when the screen was at different distances from the prism, and found that the two things were directly proportional to each other. doubling the distance of the screen doubled the length of the patch. hence the rays travelled in straight lines from the prism, and the spreading out was due to something that occurred within its substance. could it be that white light was compound, was a mixture of several constituents, and that its different constituents were differently bent? no sooner thought than tried. pierce the screen to let one of the constituents through and interpose a second prism in its path. if the spreading out depended on the prism only it should spread out just as much as before, but if it depended on the complex character of white light, this isolated simple constituent should be able to spread out no more. it did not spread out any more: a prism had no more dispersive power over it; it was deflected by the appropriate amount, but it was not analysed into constituents. it differed from sunlight in being simple. with many ingenious and beautifully simple experiments, which are quoted in full in several books on optics, he clinched the argument and established his discovery. white light was not simple but compound. it could be sorted out by a prism into an infinite number of constituent parts which were differently refracted, and the most striking of which newton named violet, indigo, blue, green, yellow, orange, and red. [illustration: fig. 64.--a single constituent of white light, obtained by the use of perforated screens is capable of no more dispersion.] at once the true nature of colour became manifest. colour resided not in the coloured object as had till now been thought, but in the light which illuminated it. red glass for instance adds nothing to sunlight. the light does not get dyed red by passing through the glass; all that the red glass does is to stop and absorb a large part of the sunlight; it is opaque to the larger portion, but it is transparent to that particular portion which affects our eyes with the sensation of red. the prism acts like a sieve sorting out the different kinds of light. coloured media act like filters, stopping certain kinds but allowing the rest to go through. leonardo's and all the ancient doctrines of colour had been singularly wrong; colour is not in the object but in the light. goethe, in his _farbenlehre_, endeavoured to controvert newton, and to reinstate something more like the old views; but his failure was complete. refraction analysed out the various constituents of white light and displayed them in the form of a series of overlapping images of the aperture, each of a different colour; this series of images we call a spectrum, and the operation we now call spectrum analysis. the reason of the defect of lenses was now plain: it was not so much a defect of the lens as a defect of light. a lens acts by refraction and brings rays to a focus. if light be simple it acts well, but if ordinary white light fall upon a lens, its different constituents have different foci; every bright object is fringed with colour, and nothing like a clear image can be obtained. [illustration: fig. 65.--showing the boundary rays of a parallel beam passing through a lens.] a parallel beam passing through a lens becomes conical; but instead of a single cone it is a sheaf or nest of cones, all having the edge of the lens as base, but each having a different vertex. the violet cone is innermost, near the lens, the red cone outermost, while the others lie between. beyond the crossing point or focus the order of cones is reversed, as the above figure shows. only the two marginal rays of the beam are depicted. if a screen be held anywhere nearer the lens than the place marked 1 there will be a whitish centre to the patch of light and a red and orange fringe or border. held anywhere beyond the region 2, the border of the patch will be blue and violet. held about 3 the colour will be less marked than elsewhere, but nowhere can it be got rid of. each point of an object will be represented in the image not by a point but by a coloured patch: a fact which amply explains the observed blurring and indistinctness. newton measured and calculated the distance between the violet and red foci--vr in the diagram--and showed that it was 1/50th the diameter of the lens. to overcome this difficulty (called chromatic aberration) telescope glasses were made small and of very long focus: some of them so long that they had no tube, all of them egregiously cumbrous. yet it was with such instruments that all the early discoveries were made. with such an instrument, for instance, huyghens discovered the real shape of saturn's ring. the defects of refractors seemed irremediable, being founded in the nature of light itself. so he gave up his "glass works"; and proceeded to think of reflexion from metal specula. a concave mirror forms an image just as a lens does, but since it does so without refraction or transmission through any substance, there is no accompanying dispersion or chromatic aberration. the first reflecting telescope he made was 1 in. diameter and 6 in. long, and magnified forty times. it acted as well as a three or four feet refractor of that day, and showed jupiter's moons. so he made a larger one, now in the library of the royal society, london, with an inscription: "the first reflecting telescope, invented by sir isaac newton, and made with his own hands." this has been the parent of most of the gigantic telescopes of the present day. fifty years elapsed before it was much improved on, and then, first by hadley and afterwards by herschel and others, large and good reflectors were constructed. the largest telescope ever made, that of lord rosse, is a newtonian reflector, fifty feet long, six feet diameter, with a mirror weighing four tons. the sextant, as used by navigators, was also invented by newton. the year after the plague, in 1667, newton returned to trinity college, and there continued his experiments on optics. it is specially to be noted that at this time, at the age of twenty-four, newton had laid the foundations of all his greatest discoveries:-[illustration: fig. 66.--newton's telescope.] the theory of fluxions; or, the differential calculus. the law of gravitation; or, the complete theory of astronomy. the compound nature of white light; or, the beginning of spectrum analysis. [illustration: fig. 67.--the sextant, as now made.] his later life was to be occupied in working these incipient discoveries out. but the most remarkable thing is that no one knew about any one of them. however, he was known as an accomplished young mathematician, and was made a fellow of his college. you remember that he had a friend there in the person of dr. isaac barrow, first lucasian professor of mathematics in the university. it happened, about 1669, that a mathematical discovery of some interest was being much discussed, and dr. barrow happened to mention it to newton, who said yes, he had worked out that and a few other similar things some time ago. he accordingly went and fetched some papers to dr. barrow, who forwarded them to other distinguished mathematicians, and it thus appeared that newton had discovered theorems much more general than this special case that was exciting so much interest. dr. barrow, being anxious to devote his time more particularly to theology, resigned his chair the same year in favour of newton, who was accordingly elected to the lucasian professorship, which he held for thirty years. this chair is now the most famous in the university, and it is commonly referred to as the chair of newton. still, however, his method of fluxions was unknown, and still he did not publish it. he lectured first on optics, giving an account of his experiments. his lectures were afterwards published both in latin and english, and are highly valued to this day. the fame of his mathematical genius came to the ears of the royal society, and a motion was made to get him elected a fellow of that body. the royal society, the oldest and most famous of all scientific societies with a continuous existence, took its origin in some private meetings, got up in london by the hon. robert boyle and a few scientific friends, during all the trouble of the commonwealth. after the restoration, charles ii. in 1662 incorporated it under royal charter; among the original members being boyle, hooke, christopher wren, and other less famous names. boyle was a great experimenter, a worthy follower of dr. gilbert. hooke began as his assistant, but being of a most extraordinary ingenuity he rapidly rose so as to exceed his master in importance. fate has been a little unkind to hooke in placing him so near to newton; had he lived in an ordinary age he would undoubtedly have shone as a star of the first magnitude. with great ingenuity, remarkable scientific insight, and consummate experimental skill, he stands in many respects almost on a level with galileo. but it is difficult to see stars even of the first magnitude when the sun is up, and thus it happens that the name and fame of this brilliant man are almost lost in the blaze of newton. of christopher wren i need not say much. he is well known as an architect, but he was a most accomplished all-round man, and had a considerable taste and faculty for science. these then were the luminaries of the royal society at the time we are speaking of, and to them newton's first scientific publication was submitted. he communicated to them an account of his reflecting telescope, and presented them with the instrument. their reception of it surprised him; they were greatly delighted with it, and wrote specially thanking him for the communication, and assuring him that all right should be done him in the matter of the invention. the bishop of salisbury (bishop burnet) proposed him for election as a fellow, and elected he was. in reply, he expressed his surprise at the value they set on the telescope, and offered, if they cared for it, to send them an account of a discovery which he doubts not will prove much more grateful than the communication of that instrument, "being in my judgment the oddest, if not the most considerable detection that has recently been made into the operations of nature." so he tells them about his optical researches and his discovery of the nature of white light, writing them a series of papers which were long afterwards incorporated and published as his _optics_. a magnificent work, which of itself suffices to place its author in the first rank of the world's men of science. the nature of white light, the true doctrine of colour, and the differential calculus! besides a good number of minor results--binomial theorem, reflecting telescope, sextant, and the like; one would think it enough for one man's life-work, but the masterpiece remains still to be mentioned. it is as when one is considering shakspeare: _king lear_, _macbeth_, _othello_,--surely a sufficient achievement,--but the masterpiece remains. comparisons in different departments are but little help perhaps, nevertheless it seems to me that in his own department, and considered simply as a man of science, newton towers head and shoulders over, not only his contemporaries--that is a small matter--but over every other scientific man who has ever lived, in a way that we can find no parallel for in other departments. other nations admit his scientific pre-eminence with as much alacrity as we do. well, we have arrived at the year 1672 and his election to the royal society. during the first year of his membership there was read at one of the meetings a paper giving an account of a very careful determination of the length of a degree (_i.e._ of the size of the earth), which had been made by picard near paris. the length of the degree turned out to be not sixty miles, but nearly seventy miles. how soon newton heard of this we do not learn--probably not for some years,--cambridge was not so near london then as it is now, but ultimately it was brought to his notice. armed with this new datum, his old speculation concerning gravity occurred to him. he had worked out the mechanics of the solar system on a certain hypothesis, but it had remained a hypothesis somewhat out of harmony with apparent fact. what if it should turn out to be true after all! he took out his old papers and began again the calculation. if gravity were the force keeping the moon in its orbit, it would fall toward the earth sixteen feet every minute. how far did it fall? the newly known size of the earth would modify the figures: with intense excitement he runs through the working, his mind leaps before his hand, and as he perceives the answer to be coming out right, all the infinite meaning and scope of his mighty discovery flashes upon him, and he can no longer see the paper. he throws down the pen; and the secret of the universe is, to one man, known. but of course it had to be worked out. the meaning might flash upon him, but its full detail required years of elaboration; and deeper and deeper consequences revealed themselves to him as he proceeded. for two years he devoted himself solely to this one object. during those years he lived but to calculate and think, and the most ludicrous stories are told concerning his entire absorption and inattention to ordinary affairs of life. thus, for instance, when getting up in a morning he would sit on the side of the bed half-dressed, and remain like that till dinner time. often he would stay at home for days together, eating what was taken to him, but without apparently noticing what he was doing. one day an intimate friend, dr. stukely, called on him and found on the table a cover laid for his solitary dinner. after waiting a long time, dr. stukely removed the cover and ate the chicken underneath it, replacing and covering up the bones again. at length newton appeared, and after greeting his friend, sat down to dinner, but on lifting the cover he said in surprise, "dear me, i thought i had not dined, but i see i have." it was by this continuous application that the _principia_ was accomplished. probably nothing of the first magnitude can be accomplished without something of the same absorbed unconsciousness and freedom from interruption. but though desirable and essential for the _work_, it was a severe tax upon the powers of the _man_. there is, in fact, no doubt that newton's brain suffered temporary aberration after this effort for a short time. the attack was slight, and it has been denied; but there are letters extant which are inexplicable otherwise, and moreover after a year or two he writes to his friends apologizing for strange and disjointed epistles, which he believed he had written without understanding clearly what he wrote. the derangement was, however, both slight and temporary: and it is only instructive to us as showing at what cost such a work as the _principia_ must be produced, even by so mighty a mind as that of newton. the first part of the work having been done, any ordinary mortal would have proceeded to publish it; but the fact is that after he had sent to the royal society his papers on optics, there had arisen controversies and objections; most of them rather paltry, to which he felt compelled to find answers. many men would have enjoyed this part of the work, and taken it as evidence of interest and success. but to newton's shy and retiring disposition these discussions were merely painful. he writes, indeed, his answers with great patience and ability, and ultimately converts the more reasonable of his opponents, but he relieves his mind in the following letter to the secretary of the royal society: "i see i have made myself a slave to philosophy, but if i get free of this present business i will resolutely bid adieu to it eternally, except what i do for my private satisfaction or leave to come out after me; for i see a man must either resolve to put out nothing new, or to become a slave to defend it." and again in a letter to leibnitz: "i have been so persecuted with discussions arising out of my theory of light that i blamed my own imprudence for parting with so substantial a blessing as my quiet to run after a shadow." this shows how much he cared for contemporary fame. so he locked up the first part of the _principia_ in his desk, doubtless intending it to be published after his death. but fortunately this was not so to be. in 1683, among the leading lights of the royal society, the same sort of notions about gravity and the solar system began independently to be bruited. the theory of gravitation seemed to be in the air, and wren, hooke, and halley had many a talk about it. hooke showed an experiment with a pendulum, which he likened to a planet going round the sun. the analogy is more superficial than real. it does not obey kepler's laws; still it was a striking experiment. they had guessed at a law of inverse squares, and their difficulty was to prove what curve a body subject to it would describe. they knew it ought to be an ellipse if it was to serve to explain the planetary motion, and hooke said he could prove that an ellipse it was; but he was nothing of a mathematician, and the others scarcely believed him. undoubtedly he had shrewd inklings of the truth, though his guesses were based on little else than a most sagacious intuition. he surmised also that gravity was the force concerned, and asserted that the path of an ordinary projectile was an ellipse, like the path of a planet--which is quite right. in fact the beginnings of the discovery were beginning to dawn upon him in the well-known way in which things do dawn upon ordinary men of genius: and had newton not lived we should doubtless, by the labours of a long chain of distinguished men, beginning with hooke, wren, and halley, have been now in possession of all the truths revealed by the _principia_. we should never have had them stated in the same form, nor proved with the same marvellous lucidity and simplicity, but the facts themselves we should by this time have arrived at. their developments and completions, due to such men as clairaut, euler, d'alembert, lagrange, laplace, airy, leverrier, adams, we should of course not have had to the same extent; because the lives and energies of these great men would have been partially consumed in obtaining the main facts themselves. the youngest of the three questioners at the time we are speaking of was edmund halley, an able and remarkable man. he had been at cambridge, doubtless had heard newton lecture, and had acquired a great veneration for him. in january, 1684, we find wren offering hooke and halley a prize, in the shape of a book worth forty shillings, if they would either of them bring him within two months a demonstration that the path of a planet subject to an inverse square law would be an ellipse. not in two months, nor yet in seven, was there any proof forthcoming. so at last, in august, halley went over to cambridge to speak to newton about the difficult problem and secure his aid. arriving at his rooms he went straight to the point. he said, "what path will a body describe if it be attracted by a centre with a force varying as the inverse square of the distance." to which newton at once replied, "an ellipse." "how on earth do you know?" said halley in amazement. "why, i have calculated it," and began hunting about for the paper. he actually couldn't find it just then, but sent it him shortly by post, and with it much more--in fact, what appeared to be a complete treatise on motion in general. with his valuable burden halley hastened to the royal society and told them what he had discovered. the society at his representation wrote to mr. newton asking leave that it might be printed. to this he consented; but the royal society wisely appointed mr. halley to see after him and jog his memory, in case he forgot about it. however, he set to work to polish it up and finish it, and added to it a great number of later developments and embellishments, especially the part concerning the lunar theory, which gave him a deal of trouble--and no wonder; for in the way he has put it there never was a man yet living who could have done the same thing. mathematicians regard the achievement now as men might stare at the work of some demigod of a bygone age, wondering what manner of man this was, able to wield such ponderous implements with such apparent ease. to halley the world owes a great debt of gratitude--first, for discovering the _principia_; second, for seeing it through the press; and third, for defraying the cost of its publication out of his own scanty purse. for though he ultimately suffered no pecuniary loss, rather the contrary, yet there was considerable risk in bringing out a book which not a dozen men living could at the time comprehend. it is no small part of the merit of halley that he recognized the transcendent value of the yet unfinished work, that he brought it to light, and assisted in its becoming understood to the best of his ability. though halley afterwards became astronomer-royal, lived to the ripe old age of eighty-six, and made many striking observations, yet he would be the first to admit that nothing he ever did was at all comparable in importance with his discovery of the _principia_; and he always used to regard his part in it with peculiar pride and pleasure. and how was the _principia_ received? considering the abstruse nature of its subject, it was received with great interest and enthusiasm. in less than twenty years the edition was sold out, and copies fetched large sums. we hear of poor students copying out the whole in manuscript in order to possess a copy--not by any means a bad thing to do, however many copies one may possess. the only useful way really to read a book like that is to pore over every sentence: it is no book to be skimmed. while the _principia_ was preparing for the press a curious incident of contact between english history and the university occurred. it seems that james ii., in his policy of catholicising the country, ordered both universities to elect certain priests to degrees without the ordinary oaths. oxford had given way, and the dean of christ church was a creature of james's choosing. cambridge rebelled, and sent eight of its members, among them mr. newton, to plead their cause before the court of high commission. judge jeffreys presided over the court, and threatened and bullied with his usual insolence. the vice-chancellor of cambridge was deprived of office, the other deputies were silenced and ordered away. from the precincts of this court of justice newton returned to trinity college to complete the _principia_. by this time newton was only forty-five years old, but his main work was done. his method of fluxions was still unpublished; his optics was published only imperfectly; a second edition of the _principia_, with additions and improvements, had yet to appear; but fame had now come upon him, and with fame worries of all kinds. by some fatality, principally no doubt because of the interest they excited, every discovery he published was the signal for an outburst of criticism and sometimes of attack. i shall not go into these matters: they are now trivial enough, but it is necessary to mention them, because to newton they evidently loomed large and terrible, and occasioned him acute torment. [illustration: fig. 68.--newton when young. (_from an engraving by b. reading after sir peter lely._)] no sooner was the _principia_ put than hooke put in his claims for priority. and indeed his claims were not altogether negligible; for vague ideas of the same sort had been floating in his comprehensive mind, and he doubtless felt indistinctly conscious of a great deal more than he could really state or prove. by indiscreet friends these two great men were set somewhat at loggerheads, and worse might have happened had they not managed to come to close quarters, and correspond privately in a quite friendly manner, instead of acting through the mischievous medium of third parties. in the next edition newton liberally recognizes the claims of both hooke and wren. however, he takes warning betimes of what he has to expect, and writes to halley that he will only publish the first two books, those containing general theorems on motion. the third book--concerning the system of the world, _i.e._ the application to the solar system--he says "i now design to suppress. philosophy is such an impertinently litigious lady that a man had as good be engaged in law-suits as have to do with her. i found it so formerly, and now i am no sooner come near her again but she gives me warning. the two books without the third will not so well bear the title 'mathematical principles of natural philosophy,' and therefore i had altered it to this, 'on the free motion of two bodies'; but on second thoughts i retain the former title: 'twill help the sale of the book--which i ought not to diminish now 'tis yours." however, fortunately, halley was able to prevail upon him to publish the third book also. it is, indeed, the most interesting and popular of the three, as it contains all the direct applications to astronomy of the truths established in the other two. some years later, when his method of fluxions was published, another and a worse controversy arose--this time with leibnitz, who had also independently invented the differential calculus. it was not so well recognized then how frequently it happens that two men independently and unknowingly work at the very same thing at the same time. the history of science is now full of such instances; but then the friends of each accused the other of plagiarism. i will not go into the controversy: it is painful and useless. it only served to embitter the later years of two great men, and it continued long after newton's death--long after both their deaths. it can hardly be called ancient history even now. but fame brought other and less unpleasant distractions than controversies. we are a curious, practical, and rather stupid people, and our one idea of honouring a man is to _vote_ for him in some way or other; so they sent newton to parliament. he went, i believe, as a whig, but it is not recorded that he spoke. it is, in fact, recorded that he was once expected to speak when on a royal commission about some question of chronometers, but that he would not. however, i dare say he made a good average member. then a little later it was realized that newton was poor, that he still had to teach for his livelihood, and that though the crown had continued his fellowship to him as lucasian professor without the necessity of taking orders, yet it was rather disgraceful that he should not be better off. so an appeal was made to the government on his behalf, and lord halifax, who exerted himself strongly in the matter, succeeding to office on the accession of william iii., was able to make him ultimately master of the mint, with a salary of some £1,200 a year. i believe he made rather a good master, and turned out excellent coins: certainly he devoted his attention to his work there in a most exemplary manner. but what a pitiful business it all is! here is a man sent by heaven to do certain things which no man else could do, and so long as he is comparatively unknown he does them; but so soon as he is found out, he is clapped into a routine office with a big salary: and there is, comparatively speaking, an end of him. it is not to be supposed that he had lost his power, for he frequently solved problems very quickly which had been given out by great continental mathematicians as a challenge to the world. we may ask why newton allowed himself to be thus bandied about instead of settling himself down to the work in which he was so pre-eminently great. well, i expect your truly great man never realizes how great he is, and seldom knows where his real strength lies. certainly newton did not know it. he several times talks of giving up philosophy altogether; and though he never really does it, and perhaps the feeling is one only born of some temporary overwork, yet he does not sacrifice everything else to it as he surely must had he been conscious of his own greatness. no; self-consciousness was the last thing that affected him. it is for a great man's contemporaries to discover him, to make much of him, and to put him in surroundings where he may flourish luxuriantly in his own heaven-intended way. however, it is difficult for us to judge of these things. perhaps if he had been maintained at the national expense to do that for which he was preternaturally fitted, he might have worn himself out prematurely; whereas by giving him routine work the scientific world got the benefit of his matured wisdom and experience. it was no small matter to the young royal society to be able to have him as their president for twenty-four years. his portrait has hung over the president's chair ever since, and there i suppose it will continue to hang until the royal society becomes extinct. the events of his later life i shall pass over lightly. he lived a calm, benevolent life, universally respected and beloved. his silver-white hair when he removed his peruke was a venerable spectacle. a lock of it is still preserved, with many other relics, in the library of trinity college. he died quietly, after a painful illness, at the ripe age of eighty-five. his body lay in state in the jerusalem chamber, and he was buried in westminster abbey, six peers bearing the pall. these things are to be mentioned to the credit of the time and the country; for after we have seen the calamitous spectacle of the way tycho and kepler and galileo were treated by their ungrateful and unworthy countries, it is pleasant to reflect that england, with all its mistakes, yet recognized _her_ great man when she received him, and honoured him with the best she knew how to give. [illustration: fig. 69.--sir isaac newton.] concerning his character, one need only say that it was what one would expect and wish. it was characterized by a modest, calm, dignified simplicity. he lived frugally with his niece and her husband, mr. conduit, who succeeded him as master of the mint. he never married, nor apparently did he ever think of so doing. the idea, perhaps, did not naturally occur to him, any more than the idea of publishing his work did. he was always a deeply religious man and a sincere christian, though somewhat of the arian or unitarian persuasion--so, at least, it is asserted by orthodox divines who understand these matters. he studied theology more or less all his life, and towards the end was greatly interested in questions of biblical criticism and chronology. by some ancient eclipse or other he altered the recognized system of dates a few hundred years; and his book on the prophecies of daniel and the revelation of st. john, wherein he identifies the beast with the church of rome in quite the orthodox way, is still by some admired. but in all these matters it is probable that he was a merely ordinary man, with natural acumen and ability doubtless, but nothing in the least superhuman. in science, the impression he makes upon me is only expressible by the words inspired, superhuman. and yet if one realizes his method of work, and the calm, uninterrupted flow of all his earlier life, perhaps his achievements become more intelligible. when asked how he made his discoveries, he replied: "by always thinking unto them. i keep the subject constantly before me, and wait till the first dawnings open slowly by little and little into a full and clear light." that is the way--quiet, steady, continuous thinking, uninterrupted and unharassed brooding. much may be done under those conditions. much ought to be sacrificed to obtain those conditions. all the best thinking work of the world has been thus done.[18] buffon said: "genius is patience." so says newton: "if i have done the public any service this way, it is due to nothing but industry and patient thought." genius patience? no, it is not quite that, or, rather, it is much more than that; but genius without patience is like fire without fuel--it will soon burn itself out. notes for lecture ix the _principia_ published 1687. newton died 1727. the law of gravitation.--every particle of matter attracts every other particle of matter with a force proportional to the mass of each and to the inverse square of the distance between them. some of newton's deductions. 1. kepler's second law (equable description of areas) proves that each planet is acted on by a force directed towards the sun as a centre of force. 2. kepler's first law proves that this central force diminishes in the same proportion as the square of the distance increases. 3. kepler's third law proves that all the planets are acted on by the same kind of force; of an intensity depending on the mass of the sun.[19] 4. so by knowing the length of year and distance of any planet from the sun, the sun's mass can be calculated, in terms of that of the earth. 5. for the satellites, the force acting depends on the mass of _their_ central body, a planet. hence the mass of any planet possessing a satellite becomes known. 6. the force constraining the moon in her orbit is the same gravity as gives terrestrial bodies their weight and regulates the motion of projectiles. [because, while a stone drops 16 feet in a second, the moon, which is 60 times as far from the centre of the earth, drops 16 feet in a minute.] * * * * * 7. the moon is attracted not only by the earth, but by the sun also; hence its orbit is perturbed, and newton calculated out the chief of these perturbations, viz.:- (the equation of the centre, discovered by hipparchus.) (_a_) the evection, discovered by hipparchus and ptolemy. (_b_) the variation, discovered by tycho brahé. (_c_) the annual equation, discovered by tycho brahé. (_d_) the retrogression of the nodes, then being observed at greenwich by flamsteed. (_e_) the variation of inclination, then being observed at greenwich by flamsteed. (_f_) the progression of the apses (with an error of one-half). (_g_) the inequality of apogee, previously unknown. (_h_) the inequality of nodes, previously unknown. 8. each planet is attracted not only by the sun but by the other planets, hence their orbits are slightly affected by each other. newton began the theory of planetary perturbations. 9. he recognized the comets as members of the solar system, obedient to the same law of gravity and moving in very elongated ellipses; so their return could be predicted (_e.g._ halley's comet). 10. applying the idea of centrifugal force to the earth considered as a rotating body, he perceived that it could not be a true sphere, and calculated its oblateness, obtaining 28 miles greater equatorial than polar diameter. 11. conversely, from the observed shape of jupiter, or any planet, the length of its day could be estimated. 12. the so-calculated shape of the earth, in combination with centrifugal force, causes the weight of bodies to vary with latitude; and newton calculated the amount of this variation. 194 lbs. at pole balance 195 lbs. at equator. 13. a homogeneous sphere attracts as if its mass were concentrated at its centre. for any other figure, such as an oblate spheroid, this is not exactly true. a hollow concentric spherical shell exerts no force on small bodies inside it. 14. the earth's equatorial protuberance, being acted on by the attraction of the sun and moon, must disturb its axis of rotation in a calculated manner; and thus is produced the precession of the equinoxes. [the attraction of the planets on the same protuberance causes a smaller and rather different kind of precession.] 15. the waters of the ocean are attracted towards the sun and moon on one side, and whirled a little further away than the solid earth on the other side: hence newton explained all the main phenomena of the tides. 16. the sun's mass being known, he calculated the height of the solar tide. 17. from the observed heights of spring and neap tides he determined the lunar tide, and thence made an estimate of the mass of the moon. reference table of numerical data. +---------+---------------+----------------------+-----------------+ | |masses in solar| height dropped by a | length of day or| | | system. |stone in first second.|time of rotation.| +---------+---------------+----------------------+-----------------+ |mercury | ·065 | 7·0 feet | 24 hours | |venus | ·885 | 15·8 " | 23-1/2 " | |earth | 1·000 | 16·1 " | 24 " | |mars | ·108 | 6·2 " | 24-1/2 " | |jupiter | 300·8 | 45·0 " | 10 " | |saturn | 89·7 | 18·4 " | 10-1/2 " | |the sun | 316000· | 436·0 " | 608 " | |the moon | about ·012 | 3·7 " | 702 " | +---------+---------------+----------------------+-----------------+ the mass of the earth, taken above as unity, is 6,000 trillion tons. _observatories._--uraniburg flourished from 1576 to 1597; the observatory of paris was founded in 1667; greenwich observatory in 1675. _astronomers-royal._--flamsteed, halley, bradley, bliss, maskelyne, pond, airy, christie. lecture ix newton's "principia" the law of gravitation, above enunciated, in conjunction with the laws of motion rehearsed at the end of the preliminary notes of lecture vii., now supersedes the laws of kepler and includes them as special cases. the more comprehensive law enables us to criticize kepler's laws from a higher standpoint, to see how far they are exact and how far they are only approximations. they are, in fact, not precisely accurate, but the reason for every discrepancy now becomes abundantly clear, and can be worked out by the theory of gravitation. we may treat kepler's laws either as immediate consequences of the law of gravitation, or as the known facts upon which that law was founded. historically, the latter is the more natural plan, and it is thus that they are treated in the first three statements of the above notes; but each proposition may be worked inversely, and we might state them thus:-1. the fact that the force acting on each planet is directed to the sun, necessitates the equable description of areas. 2. the fact that the force varies as the inverse square of the distance, necessitates motion in an ellipse, or some other conic section, with the sun in one focus. 3. the fact that one attracting body acts on all the planets with an inverse square law, causes the cubes of their mean distances to be proportional to the squares of their periodic times. not only these but a multitude of other deductions follow rigorously from the simple datum that every particle of matter attracts every other particle with a force directly proportional to the mass of each and to the inverse square of their mutual distance. those dealt with in the _principia_ are summarized above, and it will be convenient to run over them in order, with the object of giving some idea of the general meaning of each, without attempting anything too intricate to be readily intelligible. [illustration: fig. 70.] no. 1. kepler's second law (equable description of areas) proves that each planet is acted on by a force directed towards the sun as a centre of force. the equable description of areas about a centre of force has already been fully, though briefly, established. (p. 175.) it is undoubtedly of fundamental importance, and is the earliest instance of the serious discussion of central forces, _i.e._ of forces directed always to a fixed centre. we may put it afresh thus:--oa has been the motion of a particle in a unit of time; at a it receives a knock towards c, whereby in the next unit it travels along ad instead of ab. now the area of the triangle cad, swept out by the radius vector in unit time, is 1/2_bh_; _h_ being the perpendicular height of the triangle from the base ac. (fig. 70.) now the blow at a, being along the base, has no effect upon _h_; and consequently the area remains just what it would have been without the blow. a blow directed to any point other than c would at once alter the area of the triangle. one interesting deduction may at once be drawn. if gravity were a radiant force emitted from the sun with a velocity like that of light, the moving planet would encounter it at a certain apparent angle (aberration), and the force experienced would come from a point a little in advance of the sun. the rate of description of areas would thus tend to increase; whereas in reality it is constant. hence the force of gravity, if it travel at all, does so with a speed far greater than that of light. it appears to be practically instantaneous. (cf. "modern views of electricity," § 126, end of chap. xii.) again, anything like a retarding effect of the medium through which the planets move would constitute a tangential force, entirely un-directed towards the sun. hence no such frictional or retarding force can appreciably exist. it is, however, conceivable that both these effects might occur and just neutralize each other. the neutralization is unlikely to be exact for all the planets; and the fact is, that no trace of either effect has as yet been discovered. (see also p. 176.) the planets are, however, subject to forces not directed towards the sun, viz. their attractions for each other; and these perturbing forces do produce a slight discrepancy from kepler's second law, but a discrepancy which is completely subject to calculation. no. 2. kepler's first law proves that this central force diminishes in the same proportion as the square of the distance increases. to prove the connection between the inverse-square law of distance, and the travelling in a conic section with the centre of force in one focus (the other focus being empty), is not so simple. it obviously involves some geometry, and must therefore be left to properly armed students. but it may be useful to state that the inverse-square law of distance, although the simplest possible law for force emanating from a point or sphere, is not to be regarded as self-evident or as needing no demonstration. the force of a magnetic pole on a magnetized steel scrap, for instance, varies as the inverse cube of the distance; and the curve described by such a particle would be quite different from a conic section--it would be a definite class of spiral (called cotes's spiral). again, on an iron filing the force of a single pole might vary more nearly as the inverse fifth power; and so on. even when the thing concerned is radiant in straight lines, like light, the law of inverse squares is not universally true. its truth assumes, first, that the source is a point or sphere; next, that there is no reflection or refraction of any kind; and lastly, that the medium is perfectly transparent. the law of inverse squares by no means holds from a prairie fire for instance, or from a lighthouse, or from a street lamp in a fog. mutual perturbations, especially the pull of jupiter, prevent the path of a planet from being really and truly an ellipse, or indeed from being any simple re-entrant curve. moreover, when a planet possesses a satellite, it is not the centre of the planet which ever attempts to describe the keplerian ellipse, but it is the common centre of gravity of the two bodies. thus, in the case of the earth and moon, the point which really does describe a close attempt at an ellipse is a point displaced about 3000 miles from the centre of the earth towards the moon, and is therefore only 1000 miles beneath the surface. no. 3. kepler's third law proves that all the planets are acted on by the same kind of force; of an intensity depending on the mass of the sun. the third law of kepler, although it requires geometry to state and establish it for elliptic motion (for which it holds just as well as it does for circular motion), is very easy to establish for circular motion, by any one who knows about centrifugal force. if _m_ is the mass of a planet, _v_ its velocity, _r_ the radius of its orbit, and _t_ the time of describing it; 2[pi]_r_ = _vt_, and the centripetal force needed to hold it in its orbit is mv^2 4[pi]^2_mr_ ------- or ---------- _r_ t^2 now the force of gravitative attraction between the planet and the sun is _vms_ -----, r^2 where _v_ is a fixed quantity called the gravitation-constant, to be determined if possible by experiment once for all. now, expressing the fact that the force of gravitation _is_ the force holding the planet in, we write, 4[pi]^2_mr_ _vms_ ----------= ---------, t^2 r^2 whence, by the simplest algebra, r^3 _vs_ -----= ---------. t^2 4[pi]^2 the mass of the planet has been cancelled out; the mass of the sun remains, multiplied by the gravitation-constant, and is seen to be proportional to the cube of the distance divided by the square of the periodic time: a ratio, which is therefore the same for all planets controlled by the sun. hence, knowing _r_ and _t_ for any single planet, the value of _vs_ is known. no. 4. so by knowing the length of year and distance of any planet from the sun, the sun's mass can be calculated, in terms of that of the earth. no. 5. for the satellites, the force acting depends on the mass of _their_ central body, a planet. hence the mass of any planet possessing a satellite becomes known. the same argument holds for any other system controlled by a central body--for instance, for the satellites of jupiter; only instead of _s_ it will be natural to write _j_, as meaning the mass of jupiter. hence, knowing _r_ and _t_ for any one satellite of jupiter, the value of _vj_ is known. apply the argument also to the case of moon and earth. knowing the distance and time of revolution of our moon, the value of _ve_ is at once determined; _e_ being the mass of the earth. hence, _s_ and _j_, and in fact the mass of any central body possessing a visible satellite, are now known in terms of _e_, the mass of the earth (or, what is practically the same thing, in terms of _v_, the gravitation-constant). observe that so far none of these quantities are known absolutely. their relative values are known, and are tabulated at the end of the notes above, but the finding of their absolute values is another matter, which we must defer. but, it may be asked, if kepler's third law only gives us the mass of a _central_ body, how is the mass of a _satellite_ to be known? well, it is not easy; the mass of no satellite is known with much accuracy. their mutual perturbations give us some data in the case of the satellites of jupiter; but to our own moon this method is of course inapplicable. our moon perturbs at first sight nothing, and accordingly its mass is not even yet known with exactness. the mass of comets, again, is quite unknown. all that we can be sure of is that they are smaller than a certain limit, else they would perturb the planets they pass near. nothing of this sort has ever been detected. they are themselves perturbed plentifully, but they perturb nothing; hence we learn that their mass is small. the mass of a comet may, indeed, be a few million or even billion tons; but that is quite small in astronomy. but now it may be asked, surely the moon perturbs the earth, swinging it round their common centre of gravity, and really describing its own orbit about this point instead of about the earth's centre? yes, that is so; and a more precise consideration of kepler's third law enables us to make a fair approximation to the position of this common centre of gravity, and thus practically to "weigh the moon," i.e. to compare its mass with that of the earth; for their masses will be inversely as their respective distances from the common centre of gravity or balancing point--on the simple steel-yard principle. hitherto we have not troubled ourselves about the precise point about which the revolution occurs, but kepler's third law is not precisely accurate unless it is attended to. the bigger the revolving body the greater is the discrepancy: and we see in the table preceding lecture iii., on page 57, that jupiter exhibits an error which, though very slight, is greater than that of any of the other planets, when the sun is considered the fixed centre. let the common centre of gravity of earth and moon be displaced a distance _x_ from the centre of the earth, then the moon's distance from the real centre of revolution is not _r_, but _r-x_; and the equation of centrifugal force to gravitative-attraction is strictly 4[pi]^2 _ve_ --------(_r-x_) = ------, t^2 r^2 instead of what is in the text above; and this gives a slightly modified "third law." from this equation, if we have any distinct method of determining _ve_ (and the next section gives such a method), we can calculate _x_ and thus roughly weigh the moon, since _r-x_ e ----= -----, _r_ e+m but to get anything like a reasonable result the data must be very precise. no. 6. the force constraining the moon in her orbit is the same gravity as gives terrestrial bodies their weight and regulates the motion of projectiles. here we come to the newtonian verification already several times mentioned; but because of its importance i will repeat it in other words. the hypothesis to be verified is that the force acting on the moon is the same kind of force as acts on bodies we can handle and weigh, and which gives them their weight. now the weight of a mass _m_ is commonly written _mg_, where _g_ is the intensity of terrestrial gravity, a thing easily measured; being, indeed, numerically equal to twice the distance a stone drops in the first second of free fall. [see table p. 205.] hence, expressing that the weight of a body is due to gravity, and remembering that the centre of the earth's attraction is distant from us by one earth's radius (r), we can write _vm_e _mg_ = ------, r^2 or _v_e = gr^2 = 95,522 cubic miles-per-second per second. but we already know _v_e, in terms of the moon's motion, as 4[pi]^2r^3 ---------- t^2 approximately, [more accurately, see preceding note, this quantity is _v_(e + m)]; hence we can easily see if the two determinations of this quantity agree.[20] all these deductions are fundamental, and may be considered as the foundation of the _principia_. it was these that flashed upon newton during that moment of excitement when he learned the real size of the earth, and discovered his speculations to be true. the next are elaborations and amplifications of the theory, such as in ordinary times are left for subsequent generations of theorists to discover and work out. newton did not work out these remoter consequences of his theory completely by any means: the astronomical and mathematical world has been working them out ever since; but he carried the theory a great way, and here it is that his marvellous power is most conspicuous. it is his treatment of no. 7, the perturbations of the moon, that perhaps most especially has struck all future mathematicians with amazement. no. 7, no. 14, no. 15, these are the most inspired of the whole. no. 7. the moon is attracted not only by the earth, but by the sun also; hence its orbit is perturbed, and newton calculated out the chief of these perturbations. now running through the perturbations (p. 203) in order:--the first is in parenthesis, because it is mere excentricity. it is not a true perturbation at all, and more properly belongs to kepler. (_a_) the first true perturbation is what ptolemy called "the evection," the principal part of which is a periodic change in the ellipticity or excentricity of the moon's orbit, owing to the pull of the sun. it is a complicated matter, and newton only partially solved it. i shall not attempt to give an account of it. (_b_) the next, "the variation," is a much simpler affair. it is caused by the fact that as the moon revolves round the earth it is half the time nearer to the sun than the earth is, and so gets pulled more than the average, while for the other fortnight it is further from the sun than the earth is, and so gets pulled less. for the week during which it is changing from a decreasing half to a new moon it is moving in the direction of the extra pull, and hence becomes new sooner than would have been expected. all next week it is moving against the same extra pull, and so arrives at quadrature (half moon) somewhat late. for the next fortnight it is in the region of too little pull, the earth gets pulled more than it does; the effect of this is to hurry it up for the third week, so that the full moon occurs a little early, and to retard it for the fourth week, so that the decreasing half moon like the increasing half occurs behind time again. thus each syzygy (as new and full are technically called) is too early; each quadrature is too late; the maximum hurrying and slackening force being felt at the octants, or intermediate 45° points. (_c_) the "annual equation" is a fluctuation introduced into the other perturbations by reason of the varying distance of the disturbing body, the sun, at different seasons of the year. its magnitude plainly depends simply on the excentricity of the earth's orbit. both these perturbations, (_b_) and (_c_), newton worked out completely. (_d_) and (_e_) next come the retrogression of the nodes and the variation of the inclination, which at the time were being observed at greenwich by flamsteed, from whom newton frequently, but vainly, begged for data that he might complete their theory while he had his mind upon it. fortunately, halley succeeded flamsteed as astronomer-royal [see list at end of notes above], and then newton would have no difficulty in gaining such information as the national observatory could give. the "inclination" meant is the angle between the plane of the moon's orbit and that of the earth. the plane of the earth's orbit round the sun is called the ecliptic; the plane of the moon's orbit round the earth is inclined to it at a certain angle, which is slowly changing, though in a periodic manner. imagine a curtain ring bisected by a sheet of paper, and tilted to a certain angle; it may be likened to the moon's orbit, cutting the plane of the ecliptic. the two points at which the plane is cut by the ring are called "nodes"; and these nodes are not stationary, but are slowly regressing, _i.e._ travelling in a direction opposite to that of the moon itself. also the angle of tilt is varying slowly, oscillating up and down in the course of centuries. (_f_) the two points in the moon's elliptic orbit where it comes nearest to or farthest from the earth, _i.e._ the points at the extremity of the long axis of the ellipse, are called separately perigee and apogee, or together "the apses." now the pull of the sun causes the whole orbit to slowly revolve in its own plane, and consequently these apses "progress," so that the true path is not quite a closed curve, but a sort of spiral with elliptic loops. but here comes in a striking circumstance. newton states with reference to this perturbation that theory only accounts for 1-1/2° per annum, whereas observation gives 3°, or just twice as much. this is published in the _principia_ as a fact, without comment. it was for long regarded as a very curious thing, and many great mathematicians afterwards tried to find an error in the working. d'alembert, clairaut, and others attacked the problem, but were led to just the same result. it constituted the great outstanding difficulty in the way of accepting the theory of gravitation. it was suggested that perhaps the inverse square law was only a first approximation; that perhaps a more complete expression, such as a b ---+ -----, r^2 r^4 must be given for it; and so on. ultimately, clairaut took into account a whole series of neglected terms, and it came out correct; thus verifying the theory. but the strangest part of this tale is to come. for only a few years ago, prof. adams, of cambridge (neptune adams, as he is called), was editing various old papers of newton's, now in the possession of the duke of portland, and he found manuscripts bearing on this very point, and discovered that newton had reworked out the calculations himself, had found the cause of the error, had taken into account the terms hitherto neglected, and so, fifty years before clairaut, had completely, though not publicly, solved this long outstanding problem of the progression of the apses. (_g_) and (_h_) two other inequalities he calculated out and predicted, viz. variation in the motions of the apses and the nodes. neither of these had then been observed, but they were afterwards detected and verified. a good many other minor irregularities are now known--some thirty, i believe; and altogether the lunar theory, or problem of the moon's exact motion, is one of the most complicated and difficult in astronomy; the perturbations being so numerous and large, because of the enormous mass of the perturbing body. the disturbances experienced by the planets are much smaller, because they are controlled by the sun and perturbed by each other. the moon is controlled only by the earth, and perturbed by the sun. planetary perturbations can be treated as a series of disturbances with some satisfaction: not so those of the moon. and yet it is the only way at present known of dealing with the lunar theory. to deal with it satisfactorily would demand the solution of such a problem as this:--given three rigid spherical masses thrown into empty space with any initial motions whatever, and abandoned to gravity: to determine their subsequent motions. with two masses the problem is simple enough, being pretty well summed up in kepler's laws; but with three masses, strange to say, it is so complicated as to be beyond the reach of even modern mathematics. it is a famous problem, known as that of "the three bodies," but it has not yet been solved. even when it is solved it will be only a close approximation to the case of earth, moon, and sun, for these bodies are not spherical, and are not rigid. one may imagine how absurdly and hopelessly complicated a complete treatment of the motions of the entire solar system would be. no. 8. each planet is attracted not only by the sun but by the other planets, hence their orbits are slightly affected by each other. the subject of planetary perturbation was only just begun by newton. gradually (by laplace and others) the theory became highly developed; and, as everybody knows, in 1846 neptune was discovered by means of it. no. 9. he recognized the comets as members of the solar system, obedient to the same law of gravity and moving in very elongated ellipses; so their return could be predicted. it was a long time before newton recognized the comets as real members of the solar system, and subject to gravity like the rest. he at first thought they moved in straight lines. it was only in the second edition of the _principia_ that the theory of comets was introduced. halley observed a fine comet in 1682, and calculated its orbit on newtonian principles. he also calculated when it ought to have been seen in past times; and he found the year 1607, when one was seen by kepler; also the year 1531, when one was seen by appian; again, he reckoned 1456, 1380, 1305. all these appearances were the same comet, in all probability, returning every seventy-five or seventy-six years. the period was easily allowed to be not exact, because of perturbing planets. he then predicted its return for 1758, or perhaps 1759, a date he could not himself hope to see. he lived to a great age, but he died sixteen years before this date. as the time drew nigh, three-quarters of a century afterwards, astronomers were greatly interested in this first cometary prediction, and kept an eager look-out for "halley's comet." clairaut, a most eminent mathematician and student of newton, proceeded to calculate out more exactly the perturbing influence of jupiter, near which it had passed. after immense labour (for the difficulty of the calculation was extreme, and the mass of mere figures something portentous), he predicted its return on the 13th of april, 1759, but he considered that he might have made a possible error of a month. it returned on the 13th of march, 1759, and established beyond all doubt the rule of the newtonian theory over comets. [illustration: fig. 71.--well-known model exhibiting the oblate spheroidal form as a consequence of spinning about a central axis. the brass strip _a_ looks like a transparent globe when whirled, and bulges out equatorially.] no. 10. applying the idea of centrifugal force to the earth considered as a rotating body, he perceived that it could not be a true sphere, and calculated its oblateness, obtaining 28 miles greater equatorial than polar diameter. here we return to one of the more simple deductions. a spinning body of any kind tends to swell at its circumference (or equator), and shrink along its axis (or poles). if the body is of yielding material, its shape must alter under the influence of centrifugal force; and if a globe of yielding substance subject to known forces rotates at a definite pace, its shape can be calculated. thus a plastic sphere the size of the earth, held together by its own gravity, and rotating once a day, can be shown to have its equatorial diameter twenty-eight miles greater than its polar diameter: the two diameters being 8,000 and 8,028 respectively. now we have no guarantee that the earth is of yielding material: for all newton could tell it might be extremely rigid. as a matter of fact it is now very nearly rigid. but he argued thus. the water on it is certainly yielding, and although the solid earth might decline to bulge at the equator in deference to the diurnal rotation, that would not prevent the ocean from flowing from the poles to the equator and piling itself up as an equatorial ocean fourteen miles deep, leaving dry land everywhere near either pole. nothing of this sort is observed: the distribution of land and water is not thus regulated. hence, whatever the earth may be now, it must once have been plastic enough to accommodate itself perfectly to the centrifugal forces, and to take the shape appropriate to a perfectly plastic body. in all probability it was once molten, and for long afterwards pasty. thus, then, the shape of the earth can be calculated from the length of its day and the intensity of its gravity. the calculation is not difficult: it consists in imagining a couple of holes bored to the centre of the earth, one from a pole and one from the equator; filling these both with water, and calculating how much higher the water will stand in one leg of the gigantic v tube so formed than in the other. the answer comes out about fourteen miles. the shape of the earth can now be observed geodetically, and it accords with calculation, but the observations are extremely delicate; in newton's time the _size_ was only barely known, the _shape_ was not observed till long after; but on the principles of mechanics, combined with a little common-sense reasoning, it could be calculated with certainty and accuracy. no. 11. from the observed shape of jupiter or any planet the length of its day could be estimated. jupiter is much more oblate than the earth. its two diameters are to one another as 17 is to 16; the ellipticity of its disk is manifest to simple inspection. hence we perceive that its whirling action must be more violent--it must rotate quicker. as a matter of fact its day is ten [illustration: fig. 72.--jupiter.] hours long--five hours daylight and five hours night. the times of rotation of other bodies in the solar system are recorded in a table above. no. 12. the so-calculated shape of the earth, in combination with centrifugal force, causes the weight of bodies to vary with latitude; and newton calculated the amount of this variation. 194 lbs. at pole balance 195 lbs. at equator. but following from the calculated shape of the earth follow several interesting consequences. first of all, the intensity of gravity will not be the same everywhere; for at the equator a stone is further from the average bulk of the earth (say the centre) than it is at the poles, and owing to this fact a mass of 590 pounds at the pole; would suffice to balance 591 pounds at the equator, if the two could be placed in the pans of a gigantic balance whose beam straddled along an earth's quadrant. this is a _true_ variation of gravity due to the shape of the earth. but besides this there is a still larger _apparent_ variation due to centrifugal force, which affects all bodies at the equator but not those at the poles. from this cause, even if the earth were a true sphere, yet if it were spinning at its actual pace, 288 pounds at the pole could balance 289 pounds at the equator; because at the equator the true weight of the mass would not be fully appreciated, centrifugal force would virtually diminish it by 1/289th of its amount. in actual fact both causes co-exist, and accordingly the total variation of gravity observed is compounded of the real and the apparent effects; the result is that 194 pounds at a pole weighs as much as 195 pounds at the equator. no. 13. a homogeneous sphere attracts as if its mass were concentrated at its centre. for any other figure, such as an oblate spheroid, this is not exactly true. a hollow concentric spherical shell exerts no force on small bodies inside it. a sphere composed of uniform material, or of materials arranged in concentric strata, can be shown to attract external bodies as if its mass were concentrated at its centre. a hollow sphere, similarly composed, does the same, but on internal bodies it exerts no force at all. hence, at all distances above the surface of the earth, gravity decreases in inverse proportion as the square of the distance from the centre of the earth increases; but, if you descend a mine, gravity decreases in this case also as you leave the surface, though not at the same rate as when you went up. for as you penetrate the crust you get inside a concentric shell, which is thus powerless to act upon you, and the earth you are now outside is a smaller one. at what rate the force decreases depends on the distribution of density; if the density were uniform all through, the law of variation would be the direct distance, otherwise it would be more complicated. anyhow, the intensity of gravity is a maximum at the surface of the earth, and decreases as you travel from the surface either up or down. no. 14. the earth's equatorial protuberance, being acted on by the attraction of the sun and moon, must disturb its axis of rotation in a calculated manner; and thus is produced the precession of the equinoxes. here we come to a truly awful piece of reasoning. a sphere attracts as if its mass were concentrated at its centre (no. 12), but a spheroid does not. the earth is a spheroid, and hence it pulls and is pulled by the moon with a slightly uncentric attraction. in other words, the line of pull does not pass through its precise centre. now when we have a spinning body, say a top, overloaded on one side so that gravity acts on it unsymmetrically, what happens? the axis of rotation begins to rotate cone-wise, at a pace which depends on the rate of spin, and on the shape and mass of the top, as well as on the amount and leverage of the overloading. newton calculated out the rapidity of this conical motion of the axis of the earth, produced by the slightly unsymmetrical pull of the moon, and found that it would complete a revolution in 26,000 years--precisely what was wanted to explain the precession of the equinoxes. in fact he had discovered the physical cause of that precession. observe that there were three stages in this discovery of precession:-first, the observation by hipparchus, that the nodes, or intersections of the earth's orbit (the sun's apparent orbit) with the plane of the equator, were not stationary, but slowly moved. second, the description of this motion by copernicus, by the statement that it was due to a conical motion of the earth's axis of rotation about its centre as a fixed point. third, the explanation of this motion by newton as due to the pull of the moon on the equatorial protuberance of the earth. the explanation _could_ not have been previously suspected, for the shape of the earth, on which the whole theory depends, was entirely unknown till newton calculated it. another and smaller motion of a somewhat similar kind has been worked out since: it is due to the unsymmetrical attraction of the other planets for this same equatorial protuberance. it shows itself as a periodic change in the obliquity of the ecliptic, or so-called recession of the apses, rather than as a motion of the nodes.[21] no. 15. the waters of the ocean are attracted towards the sun and moon on one side, and whirled a little farther away than the solid earth on the other side: hence newton explained all the main phenomena of the tides. and now comes another tremendous generalization. the tides had long been an utter mystery. kepler likens the earth to an animal, and the tides to his breathings and inbreathings, and says they follow the moon. galileo chaffs him for this, and says that it is mere superstition to connect the moon with the tides. descartes said the moon pressed down upon the waters by the centrifugal force of its vortex, and so produced a low tide under it. everything was fog and darkness on the subject. the legend goes that an astronomer threw himself into the sea in despair of ever being able to explain the flux and reflux of its waters. newton now with consummate skill applied his theory to the effect of the moon upon the ocean, and all the main details of tidal action gradually revealed themselves to him. he treated the water, rotating with the earth once a day, somewhat as if it were a satellite acted on by perturbing forces. the moon as it revolves round the earth is perturbed by the sun. the ocean as it revolves round the earth (being held on by gravitation just as the moon is) is perturbed by both sun and moon. the perturbing effect of a body varies directly as its mass, and inversely as the cube of its distance. (the simple law of inverse square does not apply, because a perturbation is a differential effect: the satellite or ocean when nearer to the perturbing body than the rest of the earth, is attracted more, and when further off it is attracted less than is the main body of the earth; and it is these differences alone which constitute the perturbation.) the moon is the more powerful of the two perturbing bodies, hence the main tides are due to the moon; and its chief action is to cause a pair of low waves or oceanic humps, of gigantic area, to travel round the earth once in a lunar day, _i.e._ in about 24 hours and 50 minutes. the sun makes a similar but still lower pair of low elevations to travel round once in a solar day of 24 hours. and the combination of the two pairs of humps, thus periodically overtaking each other, accounts for the well-known spring and neap tides,--spring tides when their maxima agree, neap tides when the maximum of one coincides with the minimum of the other: each of which events happens regularly once a fortnight. these are the main effects, but besides these there are the effects of varying distances and obliquity to be taken into account; and so we have a whole series of minor disturbances, very like those discussed in no. 7, under the lunar theory, but more complex still, because there are two perturbing bodies instead of only one. the subject of the tides is, therefore, very recondite; and though one may give some elementary account of its main features, it will be best to defer this to a separate lecture (lecture xvii). i had better, however, here say that newton did not limit himself to the consideration of the primary oceanic humps: he pursued the subject into geographical detail. he pointed out that, although the rise and fall of the tide at mid-ocean islands would be but small, yet on stretches of coast the wave would fling itself, and by its momentum would propel the waters, to a much greater height--for instance, 20 or 30 feet; especially in some funnel-shaped openings like the bristol channel and the bay of fundy, where the concentrated impetus of the water is enormous. he also showed how the tidal waves reached different stations in successive regular order each day; and how some places might be fed with tide by two distinct channels; and that if the time of these channels happened to differ by six hours, a high tide might be arriving by one channel and a low tide by the other, so that the place would only feel the difference, and so have a very small observed rise and fall; instancing a port in china (in the gulf of tonquin) where that approximately occurs. in fact, although his theory was not, as we now know, complete or final, yet it satisfactorily explained a mass of intricate detail as well as the main features of the tides. no. 16. the sun's mass being known, he calculated the height of the solar tide. no. 17. from the observed heights of spring and neap tides he determined the lunar tide, and thence made an estimate of the mass of the moon. knowing the sun's mass and distance, it was not difficult for newton to calculate the height of the protuberance caused by it in a pasty ocean covering the whole earth. i say pasty, because, if there was any tendency for impulses to accumulate, as timely pushes given to a pendulum accumulate, the amount of disturbance might become excessive, and its calculation would involve a multitude of data. the newtonian tide ignored this, thus practically treating the motion as either dead-beat, or else the impulses as very inadequately timed. with this reservation the mid-ocean tide due to the action of the sun alone comes out about one foot, or let us say one foot for simplicity. now the actual tide observed in mid-atlantic is at the springs about four feet, at the neaps about two. the spring tide is lunar plus solar; the neap tide is lunar minus solar. hence it appears that the tide caused by the moon alone must be about three feet, when unaffected by momentum. from this datum newton made the first attempt to approximately estimate the mass of the moon. i said that the masses of satellites must be estimated, if at all, by the perturbation they are able to cause. the lunar tide is a perturbation in the diurnal motion of the sea, and its amount is therefore a legitimate mode of calculating the moon's mass. the available data were not at all good, however; nor are they even now very perfect; and so the estimate was a good way out. it is now considered that the mass of the moon is about one-eightieth that of the earth. * * * * * such are some of the gems extracted from their setting in the _principia_, and presented as clearly as i am able before you. do you realize the tremendous stride in knowledge--not a stride, as whewell says, nor yet a leap, but a flight--which has occurred between the dim gropings of kepler, the elementary truths of galileo, the fascinating but wild speculations of descartes, and this magnificent and comprehensive system of ordered knowledge. to some his genius seemed almost divine. "does mr. newton eat, drink, sleep, like other men?" said the marquis de l'hôpital, a french mathematician of no mean eminence; "i picture him to myself as a celestial genius, entirely removed from the restrictions of ordinary matter." to many it seemed as if there was nothing more to be discovered, as if the universe were now explored, and only a few fragments of truth remained for the gleaner. this is the attitude of mind expressed in pope's famous epigram:- "nature and nature's laws lay hid in night, god said, let newton be, and all was light." this feeling of hopelessness and impotence was very natural after the advent of so overpowering a genius, and it prevailed in england for fully a century. it was very natural, but it was very mischievous; for, as a consequence, nothing of great moment was done by england in science, and no englishman of the first magnitude appeared, till some who are either living now or who have lived within the present century. it appeared to his contemporaries as if he had almost exhausted the possibility of discovery; but did it so appear to newton? did it seem to him as if he had seen far and deep into the truths of this great and infinite universe? it did not. when quite an old man, full of honour and renown, venerated, almost worshipped, by his contemporaries, these were his words:-"i know not what the world will think of my labours, but to myself it seems that i have been but as a child playing on the sea-shore; now finding some pebble rather more polished, and now some shell rather more agreeably variegated than another, while the immense ocean of truth extended itself unexplored before me." and so it must ever seem to the wisest and greatest of men when brought into contact with the great things of god--that which they know is as nothing, and less than nothing, to the infinitude of which they are ignorant. newton's words sound like a simple and pleasing echo of the words of that great unknown poet, the writer of the book of job:- "lo, these are parts of his ways, but how little a portion is heard of him; the thunder of his power, who can understand?" end of part i. part ii _a couple of centuries' progress._ notes to lecture x _science during the century after newton_ the _principia_ published, 1687 roemer 1644-1710 james bradley 1692-1762 clairaut 1713-1765 euler 1707-1783 d'alembert 1717-1783 lagrange 1736-1813 laplace 1749-1827 william herschel 1738-1822 _olaus roemer_ was born in jutland, and studied at copenhagen. assisted picard in 1671 to determine the exact position of tycho's observatory on huen. accompanied picard to paris, and in 1675 read before the academy his paper "on successive propagation of light as revealed by a certain inequality in the motion of jupiter's first satellite." in 1681 he returned to copenhagen as professor of mathematics and astronomy, and died in 1710. he invented the transit instrument, mural circle, equatorial mounting for telescopes, and most of the other principal instruments now in use in observatories. he made as many observations as tycho brahé, but the records of all but the work of three days were destroyed by a great fire in 1728. _bradley_, professor of astronomy at oxford, discovered the aberration of light in 1729, while examining stars for parallax, and the nutation of the earth's axis in 1748. was appointed astronomer-royal in 1742. lecture x roemer and bradley and the velocity of light at newton's death england stood pre-eminent among the nations of europe in the sphere of science. but the pre-eminence did not last long. two great discoveries were made very soon after his decease, both by professor bradley, of oxford, and then there came a gap. a moderately great man often leaves behind him a school of disciples able to work according to their master's methods, and with a healthy spirit of rivalry which stimulates and encourages them. newton left, indeed, a school of disciples, but his methods of work were largely unknown to them, and such as were known were too ponderous to be used by ordinary men. only one fresh result, and that a small one, has ever been attained by other men working according to the methods of the _principia_. the methods were studied and commented on in england to the exclusion of all others for nigh a century, and as a consequence no really important work was done. on the continent, however, no such system of slavish imitation prevailed. those methods of newton's which had been simultaneously discovered by leibnitz were more thoroughly grasped, modified, extended, and improved. there arose a great school of french and german mathematicians, and the laurels of scientific discovery passed to france and germany--more especially, perhaps, at this time to france. england has never wholly recovered them. during the present century this country has been favoured with some giants who, as they become distant enough for their true magnitude to be perceived, may possibly stand out as great as any who have ever lived; but for the mass and bulk of scientific work at the present day we have to look to germany, with its enlightened government and extensive intellectual development. england, however, is waking up, and what its government does not do, private enterprise is beginning to accomplish. the establishment of centres of scientific and literary activity in the great towns of england, though at present they are partially encumbered with the supply of education of an exceedingly rudimentary type, is a movement that in the course of another century or so will be seen to be one of the most important and fruitful steps ever taken by this country. on the continent such centres have long existed; almost every large town is the seat of a university, and they are now liberally endowed. the university of bologna (where, you may remember, copernicus learnt mathematics) has recently celebrated its 800th anniversary. the scientific history of the century after newton, summarized in the above table of dates, embraces the labours of the great mathematicians clairaut, euler, d'alembert, and especially of lagrange and laplace. but the main work of all these men was hardly pioneering work. it was rather the surveying, and mapping out, and bringing into cultivation, of lands already discovered. probably herschel may be justly regarded as the next true pioneer. we shall not, however, properly appreciate the stages through which astronomy has passed, nor shall we be prepared adequately to welcome the discoveries of modern times unless we pay some attention to the intervening age. moreover, during this era several facts of great moment gradually came into recognition; and the importance of the discovery we have now to speak of can hardly be over-estimated. our whole direct knowledge of the planetary and stellar universe, from the early observations of the ancients down to the magnificent discoveries of a herschel, depends entirely upon our happening to possess a sense of sight. to no other of our senses do any other worlds than our own in the slightest degree appeal. we touch them or hear them never. consequently, if the human race had happened to be blind, no other world but the one it groped its way upon could ever have been known or imagined by it. the outside universe would have existed, but man would have been entirely and hopelessly ignorant of it. the bare idea of an outside universe beyond the world would have been inconceivable, and might have been scouted as absurd. we do possess the sense of sight; but is it to be supposed that we possess every sense that can be possessed by finite beings? there is not the least ground for such an assumption. it is easy to imagine a deaf race or a blind race: it is not so easy to imagine a race more highly endowed with senses than our own; and yet the sense of smell in animals may give us some aid in thinking of powers of perception which transcend our own in particular directions. if there were a race with higher or other senses than our own, or if the human race should ever in the process of development acquire such extra sense-organs, a whole universe of existent fact might become for the first time perceived by us, and we should look back upon our past state as upon a blind chrysalid form of existence in which we had been unconscious of all this new wealth of perception. it cannot be too clearly and strongly insisted on and brought home to every mind, that the mode in which the universe strikes us, our view of the universe, our whole idea of matter, and force, and other worlds, and even of consciousness, depends upon the particular set of sense-organs with which we, as men, happen to be endowed. the senses of force, of motion, of sound, of light, of touch, of heat, of taste, and of smell--these we have, and these are the things we primarily know. all else is inference founded upon these sensations. so the world appears to us. but given other sense-organs, and it might appear quite otherwise. what it is actually and truly like, therefore, is quite and for ever beyond us--so long as we are finite beings. without eyes, astronomy would be non-existent. light it is which conveys all the information we possess, or, as it would seem, ever can possess, concerning the outer and greater universe in which this small world forms a speck. light is the channel, the messenger of information; our eyes, aided by telescopes, spectroscopes, and many other "scopes" that may yet be invented, are the means by which we read the information that light brings. light travels from the stars to our eyes: does it come instantaneously? or does it loiter by the way? for if it lingers it is not bringing us information properly up to date--it is only telling us what the state of affairs was when it started on its long journey. now, it is evidently a matter of interest to us whether we see the sun as he is now, or only as he was some three hundred years ago. if the information came by express train it would be three hundred years behind date, and the sun might have gone out in the reign of queen anne without our being as yet any the wiser. the question, therefore, "at what rate does our messenger travel?" is evidently one of great interest for astronomers, and many have been the attempts made to solve it. very likely the ancient greeks pondered over this question, but the earliest writer known to me who seriously discussed the question is galileo. he suggests a rough experimental means of attacking it. first of all, it plainly comes quicker than sound. this can be perceived by merely watching distant hammering, or by noticing that the flash of a pistol is seen before its report is heard, or by listening to the noise of a flash of lightning. sound takes five seconds to travel a mile--it has about the same speed as a rifle bullet; but light is much quicker than that. the rude experiment suggested by galileo was to send two men with lanterns and screens to two distant watch-towers or neighbouring mountain tops, and to arrange that each was to watch alternate displays and obscurations of the light made by the other, and to imitate them as promptly as possible. either man, therefore, on obscuring or showing his own light would see the distant glimmer do the same, and would be able to judge if there was any appreciable interval between his own action and the response of the distant light. the experiment was actually tried by the florentine academicians,[22] with the result that, as practice improved, the interval became shorter and shorter, so that there was no reason to suppose that there was any real interval at all. light, in fact, seemed to travel instantaneously. well might they have arrived at this result. even if they had made far more perfect arrangements--for instance, by arranging a looking-glass at one of the stations in which a distant observer might see the reflection of his own lantern, and watch the obscurations and flashings made by himself, without having to depend on the response of human mechanism--even then no interval whatever could have been detected. if, by some impossibly perfect optical arrangement, a lighthouse here were made visible to us after reflection in a mirror erected at new york, so that the light would have to travel across the atlantic and back before it could be seen, even then the appearance of the light on removing a shutter, or the eclipse on interposing it, would seem to happen quite instantaneously. there would certainly be an interval: the interval would be the fiftieth part of a second (the time a stone takes to drop 1/13th of an inch), but that is too short to be securely detected without mechanism. with mechanism the thing might be managed, for a series of shutters might be arranged like the teeth of a large wheel; so that, when the wheel rotates, eclipses follow one another very rapidly; if then an eye looked through the same opening as that by which the light goes on its way to the distant mirror, a tooth might have moved sufficiently to cover up this space by the time the light returned; in which case the whole would appear dark, for the light would be stopped by a tooth, either at starting or at returning, continually. at higher speeds of rotation some light would reappear, and at lower speeds it would also reappear; by noticing, therefore, the precise speed at which there was constant eclipse the velocity of light could be determined. [illustration: fig. 73.--diagram of eye looking at a light reflected in a distant mirror through the teeth of a revolving wheel.] this experiment has now been made in a highly refined form by fizeau, and repeated by m. cornu with prodigious care and accuracy. but with these recent matters we have no concern at present. it may be instructive to say, however, that if the light had to travel two miles altogether, the wheel would have to possess 450 teeth and to spin 100 times a second (at the risk of flying to pieces) in order that the ray starting through any one of the gaps might be stopped on returning by the adjacent tooth. well might the velocity of light be called instantaneous by the early observers. an ordinary experiment seemed (and was) hopeless, and light was supposed to travel at an infinite speed. but a phenomenon was noticed in the heavens by a quick-witted and ingenious danish astronomer, which was not susceptible of any ordinary explanation, and which he perceived could at once be explained if light had a certain rate of travel--great, indeed, but something short of infinite. this phenomenon was connected with the satellites of jupiter, and the astronomer's name was roemer. i will speak first of the observation and then of the man. [illustration: fig. 74.--fizeau's wheel, shewing the appearance of distant image seen through its teeth. 1st, when stationary, next when revolving at a moderate speed, last when revolving at the high speed just sufficient to cause eclipse.] jupiter's satellites are visible, precisely as our own moon is, by reason of the shimmer of sunlight which they reflect. but as they revolve round their great planet they plunge into his shadow at one part of their course, and so become eclipsed from sunshine and invisible to us. the moment of disappearance can be sharply observed. take the first satellite as an example. the interval between successive eclipses ought to be its period of revolution round jupiter. observe this period. it was not uniform. on the average it was 42 hours 47 minutes, but it seemed to depend on the time of year. when roemer observed in spring it was less, and in autumn it was more than usual. this was evidently a puzzling fact: what on earth can our year have to do with the motion of a moon of jupiter's? it was probably, therefore, only an apparent change, caused either by our greater or less distance from jupiter, or else by our greater or less speed of travelling to or from him. considering it thus, he was led to see that, when the time of revolution seemed longest, we were receding fastest from jupiter, and when shortest, approaching fastest. _if_, then, light took time on its journey, _if_ it travelled progressively, the whole anomaly would be explained. in a second the earth goes nineteen miles; therefore in 42-3/4 hours (the time of revolution of jupiter's first satellite) it goes 2·9 million (say three million) miles. the eclipse happens punctually, but we do not see it till the light conveying the information has travelled the extra three million miles and caught up the earth. evidently, therefore, by observing how much the apparent time of revolution is lengthened in one part of the earth's orbit and shortened in another, getting all the data accurately, and assuming the truth of our hypothetical explanation, we can calculate the velocity of light. this is what roemer did. now the maximum amount of retardation is just about fifteen seconds. hence light takes this time to travel three million miles; therefore its velocity is three million divided by fifteen, say 200,000, or, as we now know more exactly, 186,000 miles every second. note that the delay does not depend on our _distance_, but on our _speed_. one can tell this by common-sense as soon as we grasp the general idea of the explanation. a velocity cannot possibly depend on a distance only. [illustration: fig. 75.--eclipses of one of jupiter's satellites. a diagram intended to illustrate the dependence of its apparent time of revolution (from eclipse to eclipse) on the motion of the earth; but not illustrating the matter at all well. tt' t'' are successive positions of the earth, while jj' j'' are corresponding positions of jupiter.] roemer's explanation of the anomaly was not accepted by astronomers. it excited some attention, and was discussed, but it was found not obviously applicable to any of the satellites except the first, and not very simply and satisfactorily even to that. i have, of course, given you the theory in its most elementary and simple form. in actual fact a host of disturbing and complicated considerations come in--not so violently disturbing for the first satellite as for the others, because it moves so quickly, but still complicated enough. the fact is, the real motion of jupiter's satellites is a most difficult problem. the motion even of our own moon (the lunar theory) is difficult enough: perturbed as its motion is by the sun. you know that newton said it cost him more labour than all the rest of the _principia_. but the motion of jupiter's satellites is far worse. no one, in fact, has yet worked their theory completely out. they are perturbed by the sun, of course, but they also perturb each other, and jupiter is far from spherical. the shape of jupiter, and their mutual attractions, combine to make their motions most peculiar and distracting. hence an error in the time of revolution of a satellite was not _certainly_ due to the cause roemer suggested, unless one could be sure that the inequality was not a real one, unless it could be shown that the theory of gravitation was insufficient to account for it. this had not then been done; so the half-made discovery was shelved, and properly shelved, as a brilliant but unverified speculation. it remained on the shelf for half a century, and was no doubt almost forgotten. [illustration: fig. 76.--a transit-instrument for the british astronomical expedition, 1874. shewing in its essential features the simplest form of such an instrument.] now a word or two about the man. he was a dane, educated at copenhagen, and learned in the mathematics. we first hear of him as appointed to assist picard, the eminent french geodetic surveyor (whose admirable work in determining the length of a degree you remember in connection with newton), who had come over to denmark with the object of fixing the exact site of the old and extinct tychonic observatory in the island of huen. for of course the knowledge of the exact latitude and longitude of every place whence numerous observations have been taken must be an essential to the full interpretation of those observations. the measurements being finished, young roemer accompanied picard to paris, and here it was, a few years after, that he read his famous paper concerning "an inequality in the motion of jupiter's first satellite," and its explanation by means of an hypothesis of "the successive propagation of light." the later years of his life he spent in copenhagen as a professor in the university and an enthusiastic observer of the heavens,--not a descriptive observer like herschel, but a measuring observer like sir george airy or tycho brahé. he was, in fact, a worthy follower of tycho, and the main work of his life is the development and devising of new and more accurate astronomical instruments. many of the large and accurate instruments with which a modern observatory is furnished are the invention of this dane. one of the finest observatories in the world is the russian one at pulkowa, and a list of the instruments there reads like an extended catalogue of roemer's inventions. he not only _invented_ the instruments, he had them made, being allowed money for the purpose; and he used them vigorously, so that at his death he left great piles of manuscript stored in the national observatory. unfortunately this observatory was in the heart of the city, and was thus exposed to a danger from which such places ought to be as far as possible exempt. some eighteen years after roemer's death a great conflagration broke out in copenhagen, and ruined large portions of the city. the successor to roemer, horrebow by name, fled from his house, with such valuables as he possessed, to the observatory, and there went on with his work. but before long the wind shifted, and to his horror he saw the flames coming his way. he packed up his own and his predecessor's manuscript observations in two cases, and prepared to escape with them, but the neighbours had resorted to the observatory as a place of safety, and so choked up the staircase with their property that he was barely able to escape himself, let alone the luggage, and everything was lost. [illustration: fig. 77.--diagram of equatorially mounted telescope; ce is the polar axis parallel to the axis of the earth; ab the declination axis. the diurnal motion is compensated by motion about the polar axis only, the other being clamped.] of all the observations, only three days' work remains, and these were carefully discussed by dr. galle, of berlin, in 1845, and their nutriment extracted. these ancient observations are of great use for purposes of comparison with the present state of the heavens, and throw light upon possible changes that are going on. of course nowadays such a series of observations would be printed and distributed in many libraries, and so made practically indestructible. sad as the disaster was to the posthumous fame of the great observer, a considerable compensation was preparing. the very year that the fire occurred in denmark a quiet philosopher in england was speculating and brooding on a remarkable observation that he had made concerning the apparent motion of certain stars, and he was led thereby to a discovery of the first magnitude concerning the speed of light--a discovery which resuscitated the old theory of roemer about jupiter's satellites, and made both it and him immortal. james bradley lived a quiet, uneventful, studious life, mainly at oxford but afterwards at the national observatory at greenwich, of which he was third astronomer-royal, flamsteed and halley having preceded him in that office. he had taken orders, and lectured at oxford as savilian professor. it is said that he pondered his great discovery while pacing the long walk at magdalen college--and a beautiful place it is to meditate in. bradley was engaged in making observations to determine if possible the parallax of some of the fixed stars. parallax means the apparent relative shift of bodies due to a change in the observer's position. it is parallax which we observe when travelling by rail and looking out of window at the distant landscape. things at different distances are left behind at different apparent rates, and accordingly they seem to move relatively to each other. the most distant objects are least affected; and anything enormously distant, like the moon, is not subject to this effect, but would retain its position however far we travelled, unless we had some extraordinarily precise means of observation. so with the fixed stars: they were being observed from a moving carriage--viz. the earth--and one moving at the rate of nineteen miles a second. unless they were infinitely distant, or unless they were all at the same distance, they must show relative apparent motions among themselves. seen from one point of the earth's orbit, and then in six months from an opposite point, nearly 184 million miles away, surely they must show some difference of aspect. remember that the old copernican difficulty had never been removed. if the earth revolved round the sun, how came it that the fixed stars showed no parallax? the fact still remained a surprise, and the question a challenge. picard, like other astronomers, supposed that it was only because the methods of observation had not been delicate enough; but now that, since the invention of the telescope and the founding of national observatories, accuracy hitherto undreamt of was possible, why not attack the problem anew? this, then, he did, watching the stars with great care to see if in six months they showed any change in absolute position with reference to the pole of the heavens; any known secular motion of the pole, such as precession, being allowed for. already he thought he detected a slight parallax for several stars near the pole, and the subject was exciting much interest. bradley determined to attempt the same investigation. he was not destined to succeed in it. not till the present century was success in that most difficult observation achieved; and even now it cannot be done by the absolute methods then attempted; but, as so often happens, bradley, in attempting one thing, hit upon another, and, as it happened, one of still greater brilliance and importance. let us trace the stages of his discovery. atmospheric refraction made horizon observations useless for the delicacy of his purpose, so he chose stars near the zenith, particularly one--[gamma] draconis. this he observed very carefully at different seasons of the year by means of an instrument specially adapted for zenith observations, viz. a zenith sector. the observations were made in conjunction with a friend of his, an amateur astronomer named molyneux, and they were made at kew. molyneux was shortly made first lord of the admiralty, or something important of that sort, and gave up frivolous pursuits. so bradley observed alone. they observed the star accurately early in the month of december, and then intended to wait six months. but from curiosity bradley observed it again only about a week later. to his surprise, he found that it had already changed its position. he recorded his observation on the back of an old envelope: it was his wont thus to use up odd scraps of paper--he was not, i regret to say, a tidy or methodical person--and this odd piece of paper turned up long afterwards among his manuscripts. it has been photographed and preserved as an historical relic. again and again he repeated the observation of the star, and continually found it moving still a little further and further south, an excessively small motion, but still an appreciable one--not to be set down to errors of observation. so it went on till march. it then waited, and after a bit longer began to return, until june. by september it was displaced as much to the north as it had been to the south, and by december it had got back to its original position. it had described, in fact, a small oscillation in the course of the year. the motion affected neighbouring stars in a similar way, and was called an "aberration," or wandering from their true place. for a long time bradley pondered over this observation, and over others like them which he also made. he found one group of stars describing small circles, while others at a distance from them were oscillating in straight lines, and all the others were describing ellipses. unless this state of things were cleared up, accurate astronomy was impossible. the fixed stars!--they were not fixed a bit. to refined and accurate observation, such as was now possible, they were all careering about in little orbits having a reference to the earth's year, besides any proper motion which they might really have of their own, though no such motion was at present known. not till herschel was that discovered; not till this extraordinary aberration was allowed for could it be discovered. the effect observed by bradley and molyneux must manifestly be only an apparent motion: it was absurd to suppose a real stellar motion regulating itself according to the position of the earth. parallax could not do it, for that would displace stars relatively among each other--it would not move similarly a set of neighbouring stars. at length, four years after the observation, the explanation struck him, while in a boat upon the thames. he noticed the apparent direction of the wind changed whenever the boat started. the wind veered when the boat's motion changed. of course the cause of this was obvious enough--the speed of the wind and the speed of the boat were compounded, and gave an apparent direction of the wind other than the true direction. but this immediately suggested a cause for what he had observed in the heavens. he had been observing an apparent direction of the stars other than the true direction, because he was observing from a moving vehicle. the real direction was doubtless fixed: the apparent direction veered about with the motion of the earth. it must be that light did not travel instantaneously, but gradually, as roemer had surmised fifty years ago; and that the motion of the light was compounded with the motion of the earth. think of a stream of light or anything else falling on a moving carriage. the carriage will run athwart the stream, the occupants of the carriage will mistake its true direction. a rifle fired through the windows of a railway carriage by a man at rest outside would make its perforations not in the true line of fire unless the train is stationary. if the train is moving, the line joining the holes will point to a place in advance of where the rifle is really located. so it is with the two glasses of a telescope, the object-glass and eye-piece, which are pierced by the light; an astronomer, applying his eye to the tube and looking for the origin of the disturbance, sees it apparently, but not in its real position--its apparent direction is displaced in the direction of the telescope's motion; by an amount depending on the ratio of the velocity of the earth to the velocity of light, and on the angle between those two directions. [illustration: fig. 78.--aberration diagram. the light-ray l penetrates the object-glass of the moving telescope at o, but does not reach the eye-piece until the telescope has travelled to the second position. consequently a moving telescope does not point out the true direction of the light, but aims at a point a little in advance.] but how minute is the displacement! the greatest effect is obtained when the two motions are at right angles to each other, _i.e._ when the star seen is at right angles to the direction of the earth's motion, but even then it is only 20", or 1/180th part of a degree; one-ninetieth of the moon's apparent diameter. it could not be detected without a cross-wire in the telescope, and would only appear as a slight displacement from the centre of the field, supposing the telescope accurately pointed to the true direction. but if this explanation be true, it at once gives a method of determining the velocity of light. the maximum angle of deviation, represented as a ratio of arc ÷ radius, amounts to 1 1 ----------- ·0001 = ----- 180 × 57-1/3 10,000 (a gradient of 1 foot in two miles). in other words, the velocity of light must be 10,000 times as great as the velocity of the earth in its orbit. this amounts to a speed of 190,000 miles a second--not so very different from what roemer had reckoned it in order to explain the anomalies of jupiter's first satellite. stars in the direction in which the earth was moving would not be thus affected; there would be nothing in mere approach or recession to alter direction or to make itself in any way visible. stars at right angles to the earth's line of motion would be most affected, and these would be all displaced by the full amount of 20 seconds of arc. stars in intermediate directions would be displaced by intermediate amounts. but the line of the earth's motion is approximately a circle round the sun, hence the direction of its advance is constantly though slowly changing, and in one year it goes through all the points of the compass. the stars, being displaced always in the line of advance, must similarly appear to describe little closed curves, always a quadrant in advance of the earth, completing their orbits once a year. those near the pole of the ecliptic will describe circles, being always at right angles to the motion. those in the plane of the ecliptic (near the zodiac) will be sometimes at right angles to the motion, but at other times will be approached or receded from; hence these will oscillate like pendulums once a year; and intermediate stars will have intermediate motions--that is to say, will describe ellipses of varying excentricity, but all completed in a year, and all with the major axis 20". this agreed very closely with what was observed. the main details were thus clearly and simply explained by the hypothesis of a finite velocity for light, "the successive propagation of light in time." this time there was no room for hesitation, and astronomers hailed the discovery with enthusiasm. not yet, however, did bradley rest. the finite velocity of light explained the major part of the irregularities he had observed, but not the whole. the more carefully he measured the amount of the deviation, the less completely accurate became its explanation. there clearly was a small outstanding error or discrepancy; the stars were still subject to an unexplained displacement--not, indeed, a displacement that repeated itself every year, but one that went through a cycle of changes in a longer period. the displacement was only about half that of aberration, and having a longer period was rather more difficult to detect securely. but the major difficulty was the fact that the two sorts of disturbances were co-existent, and the skill of disentangling them, and exhibiting the true and complete cause of each inequality, was very brilliant. for nineteen years did bradley observe this minor displacement, and in that time he saw it go through a complete cycle. its cause was now clear to him; the nineteen-year period suggested the explanation. it is the period in which the moon goes through all her changes--a period known to the ancients as the lunar cycle, or metonic cycle, and used by them to predict eclipses. it is still used for the first rough approximation to the prediction of eclipses, and to calculate easter. the "golden number" of the prayer-book is the number of the year in this cycle. the cause of the second inequality, or apparent periodic motion of the stars, bradley made out to be a nodding motion of the earth's axis. the axis of the earth describes its precessional orbit or conical motion every 26,000 years, as had long been known; but superposed upon this great movement have now been detected minute nods, each with a period of nineteen years. the cause of the nodding is completely accounted for by the theory of gravitation, just as the precession of the equinoxes was. both disturbances result from the attraction of the moon on the non-spherical earth--on its protuberant equator. "nutation" is, in fact, a small perturbation of precession. the motion may be observed in a non-sleeping top. the slow conical motion of the top's slanting axis represents the course of precession. sometimes this path is loopy, and its little nods correspond to nutation. the probable existence of some such perturbation had not escaped the sagacity of newton, and he mentions something about it in the _principia_, but thinks it too small to be detected by observation. he was thinking, however, of a solar disturbance rather than a lunar one, and this is certainly very small, though it, too, has now been observed. newton was dead before bradley made these great discoveries, else he would have been greatly pleased to hear of them. these discoveries of aberration and nutation, says delambre, the great french historian of science, secure to their author a distinguished place after hipparchus and kepler among the astronomers of all ages and all countries. notes to lecture xi _lagrange_ and _laplace_, both tremendous mathematicians, worked very much in alliance, and completed newton's work. the _mécanique céleste_ contains the higher intricacies of astronomy mathematically worked out according to the theory of gravitation. they proved the solar system to be stable; all its inequalities being periodic, not cumulative. and laplace suggested the "nebular hypothesis" concerning the origin of sun and planets: a hypothesis previously suggested, and to some extent, elaborated, by kant. a list of some of the principal astronomical researches of lagrange and laplace:--libration of the moon. long inequality of jupiter and saturn. perturbations of jupiter's satellites. perturbations of comets. acceleration of the moon's mean motion. improved lunar theory. improvements in the theory of the tides. periodic changes in the form and obliquity of the earth's orbit. stability of the solar system considered as an assemblage of rigid bodies subject to gravity. the two equations which establish the stability of the solar system are:- _sum (me^2[square root]d) = constant,_ and _sum (m tan^2[theta][square root]d) = constant;_ where _m_ is the mass of each planet, _d_ its mean distance from the sun, _e_ the excentricity of its orbit, and [theta] the inclination of its plane. however the expressions above formulated may change for individual planets, the sum of them for all the planets remains invariable. the period of the variations in excentricity of the earth's orbit is 86,000 years; the period of conical revolution of the earth's axis is 25,800 years. about 18,000 years ago the excentricity was at a maximum. lecture xi lagrange and laplace--the stability of the solar system, and the nebular hypothesis laplace was the son of a small farmer or peasant of normandy. his extraordinary ability was noticed by some wealthy neighbours, and by them he was sent to a good school. from that time his career was one brilliant success, until in the later years of his life his prominence brought him tangibly into contact with the deteriorating influence of politics. perhaps one ought rather to say trying than deteriorating; for they seem trying to a strong character, deteriorating to a weak one--and unfortunately, laplace must be classed in this latter category. it has always been the custom in france for its high scientific men to be conspicuous also in politics. it seems to be now becoming the fashion in this country also, i regret to say. the _life_ of laplace is not specially interesting, and i shall not go into it. his brilliant mathematical genius is unquestionable, and almost unrivalled. he is, in fact, generally considered to come in this respect next after newton. his talents were of a more popular order than those of lagrange, and accordingly he acquired fame and rank, and rose to the highest dignities. nevertheless, as a man and a politician he hardly commands our respect, and in time-serving adjustability he is comparable to the redoubtable vicar of bray. his scientific insight and genius were however unquestionably of the very highest order, and his work has been invaluable to astronomy. i will give a short sketch of some of his investigations, so far as they can be made intelligible without overmuch labour. he worked very much in conjunction with lagrange, a more solid though a less brilliant man, and it is both impossible and unnecessary for us to attempt to apportion respective shares of credit between these two scientific giants, the greatest scientific men that france ever produced. first comes a research into the libration of the moon. this was discovered by galileo in his old age at arcetri, just before his blindness. the moon, as every one knows, keeps the same face to the earth as it revolves round it. in other words, it does not rotate with reference to the earth, though it does rotate with respect to outside bodies. its libration consists in a sort of oscillation, whereby it shows us now a little more on one side, now a little more on the other, so that altogether we are cognizant of more than one-half of its surface--in fact, altogether of about three-fifths. it is a simple and unimportant matter, easily explained. the motion of the moon may be analyzed into a rotation about its own axis combined with a revolution about the earth. the speed of the rotation is quite uniform, the speed of the revolution is not quite uniform, because the orbit is not circular but elliptical, and the moon has to travel faster in perigee than in apogee (in accordance with kepler's second law). the consequence of this is that we see a little too far round the body of the moon, first on one side, then on the other. hence it _appears_ to oscillate slightly, like a lop-sided fly-wheel whose revolutions have been allowed to die away so that they end in oscillations of small amplitude.[23] its axis of rotation, too, is not precisely perpendicular to its plane of revolution, and therefore we sometimes see a few hundred miles beyond its north pole, sometimes a similar amount beyond its south. lastly, there is a sort of parallax effect, owing to the fact that we see the rising moon from one point of view, and the setting moon from a point 8,000 miles distant; and this base-line of the earth's diameter gives us again some extra glimpses. this diurnal or parallactic libration is really more effective than the other two in extending our vision into the space-facing hemisphere of the moon. these simple matters may as well be understood, but there is nothing in them to dwell upon. the far side of the moon is probably but little worth seeing. its features are likely to be more blurred with accumulations of meteoric dust than are those of our side, but otherwise they are likely to be of the same general character. the thing of real interest is the fact that the moon does turn the same face towards us; _i.e._ has ceased to rotate with respect to the earth (if ever it did so). the stability of this state of things was shown by lagrange to depend on the shape of the moon. it must be slightly egg-shape, or prolate--extended in the direction of the earth; its earth-pointing diameter being a few hundred feet longer than its visible diameter; a cause slight enough, but nevertheless sufficient to maintain stability, except under the action of a distinct disturbing cause. the prolate or lemon-like shape is caused by the gravitative pull of the earth, balanced by the centrifugal whirl. the two forces balance each other as regards motion, but between them they have strained the moon a trifle out of shape. the moon has yielded as if it were perfectly plastic; in all probability it once was so. it may be interesting to note for a moment the correlative effect of this aspect of the moon, if we transfer ourselves to its surface in imagination, and look at the earth (cf. fig. 41). the earth would be like a gigantic moon of four times our moon's diameter, and would go through its phases in regular order. but it would not rise or set: it would be fixed in the sky, and subject only to a minute oscillation to and fro once a month, by reason of the "libration" we have been speaking of. its aspect, as seen by markings on its surface, would rapidly change, going through a cycle in twenty-four hours; but its permanent features would be usually masked by lawless accumulations of cloud, mainly aggregated in rude belts parallel to the equator. and these cloudy patches would be the most luminous, the whitest portions; for of course it would be their silver lining that we would then be looking on.[24] next among the investigations of lagrange and laplace we will mention the long inequality of jupiter and saturn. halley had found that jupiter was continually lagging behind its true place as given by the theory of gravitation; and, on the other hand, that saturn was being accelerated. the lag on the part of jupiter amounted to about 34-1/2 minutes in a century. overhauling ancient observations, however, halley found signs of the opposite state of things, for when he got far enough back jupiter was accelerated and saturn was being retarded. here was evidently a case of planetary perturbation, and laplace and lagrange undertook the working of it out. they attacked it as a case of the problem of three bodies, viz. the sun, jupiter, and saturn; which are so enormously the biggest of the known bodies in the system that insignificant masses like the earth, mars, and the rest, may be wholly neglected. they succeeded brilliantly, after a long and complex investigation: succeeded, not in solving the problem of the three bodies, but, by considering their mutual action as perturbations superposed on each other, in explaining the most conspicuous of the observed anomalies of their motion, and in laying the foundation of a general planetary theory. [illustration: fig. 79.--shewing the three conjunction places in the orbits of jupiter and saturn. the two planets are represented as leaving one of the conjunctions where jupiter was being pulled back and saturn being pulled forward by their mutual attraction.] one of the facts that plays a large part in the result was known to the old astrologers, viz. that jupiter and saturn come into conjunction with a certain triangular symmetry; the whole scheme being called a trigon, and being mentioned several times by kepler. it happens that five of jupiter's years very nearly equal two of saturn's,[25] so that they get very nearly into conjunction three times in every five jupiter years, but not exactly. the result of this close approach is that periodically one pulls the other on and is itself pulled back; but since the three points progress, it is not always the same planet which gets pulled back. the complete theory shows that in the year 1560 there was no marked perturbation: before that it was in one direction, while afterwards it was in the other direction, and the period of the whole cycle of disturbances is 929 of our years. the solution of this long outstanding puzzle by the theory of gravitation was hailed with the greatest enthusiasm by astronomers, and it established the fame of the two french mathematicians. next they attacked the complicated problem of the motions of jupiter's satellites. they succeeded in obtaining a theory of their motions which represented fact very nearly indeed, and they detected the following curious relationship between the satellites:--the speed of the first satellite + twice the speed of the second is equal to the speed of the third. they found this, not empirically, after the manner of kepler, but as a deduction from the law of gravitation; for they go on to show that even if the satellites had not started with this relation they would sooner or later, by mutual perturbation, get themselves into it. one singular consequence of this, and of another quite similar connection between their positions, is that all three satellites can never be eclipsed at once. the motion of the fourth satellite is less tractable; it does not so readily form an easy system with the others. after these great successes the two astronomers naturally proceeded to study the mutual perturbations of all other bodies in the solar system. and one very remarkable discovery they made concerning the earth and moon, an account of which will be interesting, though the details and processes of calculation are quite beyond us in a course like this. astronomical theory had become so nearly perfect by this time, and observations so accurate, that it was possible to calculate many astronomical events forwards or backwards, over even a thousand years or more, with admirable precision. now, halley had studied some records of ancient eclipses, and had calculated back by means of the lunar theory to see whether the calculation of the time they ought to occur would agree with the record of the time they did occur. to his surprise he found a discrepancy, not a large one, but still one quite noticeable. to state it as we know it now:--an eclipse a century ago happened twelve seconds later than it ought to have happened by theory; two centuries back the error amounted to forty-eight seconds, in three centuries it would be 108 seconds, and so on; the lag depending on the square of the time. by research, and help from scholars, he succeeded in obtaining the records of some very ancient eclipses indeed. one in egypt towards the end of the tenth century a.d.; another in 201 a.d.; another a little before christ; and one, the oldest of all of which any authentic record has been preserved, observed by the chaldæan astronomers in babylon in the reign of hezekiah. calculating back to this splendid old record of a solar eclipse, over the intervening 2,400 years, the calculated and the observed times were found to disagree by nearly two hours. pondering over an explanation of the discrepancy, halley guessed that it must be because the moon's motion was not uniform, it must be going quicker and quicker, gaining twelve seconds each century on its previous gain--a discovery announced by him as "the acceleration of the moon's mean motion." the month was constantly getting shorter. what was the physical cause of this acceleration according to the theory of gravitation? many attacked the question, but all failed. this was the problem laplace set himself to work out. a singular and beautiful result rewarded his efforts. you know that the earth describes an elliptic orbit round the sun: and that an ellipse is a circle with a certain amount of flattening or "excentricity."[26] well, laplace found that the excentricity of the earth's orbit must be changing, getting slightly less; and that this change of excentricity would have an effect upon the length of the month. it would make the moon go quicker. one can almost see how it comes about. a decrease in excentricity means an increase in mean distance of the earth from the sun. this means to the moon a less solar perturbation. now one effect of the solar perturbation is to keep the moon's orbit extra large: if the size of its orbit diminishes, its velocity must increase, according to kepler's third law. laplace calculated the amount of acceleration so resulting, and found it ten seconds a century; very nearly what observation required; for, though i have quoted observation as demanding twelve seconds per century, the facts were not then so distinctly and definitely ascertained. this calculation for a long time seemed thoroughly satisfactory, but it is not the last word on the subject. quite lately an error has been found in the working, which diminishes the theoretical gravitation-acceleration to six seconds a century instead of ten, thus making it insufficient to agree exactly with fact. the theory of gravitation leaves an outstanding error. (the point is now almost thoroughly understood, and we shall return to it in lecture xviii). but another question arises out of this discussion. i have spoken of the excentricity of the earth's orbit as decreasing. was it always decreasing? and if so, how far back was it so excentric that at perihelion the earth passed quite near the sun? if it ever did thus pass near the sun, the inference is manifest--the earth must at one time have been thrown off, or been separated off, from the sun. if a projectile could be fired so fast that it described an orbit round the earth--and the speed of fire to attain this lies between five and seven miles a second (not less than the one, nor more than the other)--it would ever afterwards pass through its point of projection as one point of its elliptic orbit; and its periodic return through that point would be the sign of its origin. similarly, if a satellite does _not_ come near its central orb, and can be shown never to have been near it, the natural inference is that it has _not_ been born from it, but has originated in some other way. the question which presented itself in connexion with the variable ellipticity of the earth's orbit was the following:--had it always been decreasing, so that once it was excentric enough just to graze the sun at perihelion as a projected body would do? into the problem thus presented lagrange threw himself, and he succeeded in showing that no such explanation of the origin of the earth is possible. the excentricity of the orbit, though now decreasing, was not always decreasing; ages ago it was increasing: it passes through periodic changes. eighteen thousand years ago its excentricity was a maximum; since then it has been diminishing, and will continue to diminish for 25,000 years more, when it will be an almost perfect circle; it will then begin to increase again, and so on. the obliquity of the ecliptic is also changing periodically, but not greatly: the change is less than three degrees. this research has, or ought to have, the most transcendent interest for geologists and geographers. you know that geologists find traces of extraordinary variations of temperature on the surface of the earth. england was at one time tropical, at another time glacial. far away north, in spitzbergen, evidence of the luxuriant vegetation of past ages has been found; and the explanation of these great climatic changes has long been a puzzle. does not the secular variation in excentricity of the earth's orbit, combined with the precession of the equinoxes, afford a key? and if a key at all, it will be an accurate key, and enable us to calculate back with some precision to the date of the glacial epoch; and again to the time when a tropical flora flourished in what is now northern europe, _i.e._ to the date of the carboniferous era. this aspect of the subject has recently been taught with vigour and success by dr. croll in his book "climate and time." a brief and partial explanation of the matter may be given, because it is a point of some interest and is also one of fair simplicity. every one knows that the climatic conditions of winter and summer are inverted in the two hemispheres, and that at present the sun is nearest to us in our (northern) winter. in other words, the earth's axis is inclined so as to tilt its north pole away from the sun at perihelion, or when the earth is at the part of its elliptic orbit nearest the sun's focus; and to tilt it towards the sun at aphelion. the result of this present state of things is to diminish the intensity of the average northern winter and of the average northern summer, and on the other hand to aggravate the extremes of temperature in the southern hemisphere; all other things being equal. of course other things are not equal, and the distribution of land and sea is a still more powerful climatic agent than is the three million miles or so extra nearness of the sun. but it is supposed that the antarctic ice-cap is larger than the northern, and increased summer radiation with increased winter cold would account for this. but the present state of things did not always obtain. the conical movement of the earth's axis (now known by a curious perversion of phrase as "precession") will in the course of 13,000 years or so cause the tilt to be precisely opposite, and then we shall have the more extreme winters and summers instead of the southern hemisphere. if the change were to occur now, it might not be overpowering, because now the excentricity is moderate. but if it happened some time back, when the excentricity was much greater, a decidedly different arrangement of climate may have resulted. there is no need to say _if_ it happened some time back: it did happen, and accordingly an agent for affecting the distribution of mean temperature on the earth is to hand; though whether it is sufficient to achieve all that has been observed by geologists is a matter of opinion. once more, the whole diversity of the seasons depends on the tilt of the earth's axis, the 23° by which it is inclined to a perpendicular to the orbital plane; and this obliquity or tilt is subject to slow fluctuations. hence there will come eras when all causes combine to produce a maximum extremity of seasons in the northern hemisphere, and other eras when it is the southern hemisphere which is subject to extremes. but a grander problem still awaited solution--nothing less than the fate of the whole solar system. here are a number of bodies of various sizes circulating at various rates round one central body, all attracted by it, and all attracting each other, the whole abandoned to the free play of the force of gravitation: what will be the end of it all? will they ultimately approach and fall into the sun, or will they recede further and further from him, into the cold of space? there is a third possible alternative: may they not alternately approach and recede from him, so as on the whole to maintain a fair approximation to their present distances, without great and violent extremes of temperature either way? if any one planet of the system were to fall into the sun, more especially if it were a big one like jupiter or saturn, the heat produced would be so terrific that life on this earth would be destroyed, even at its present distance; so that we are personally interested in the behaviour of the other planets as well as in the behaviour of our own. the result of the portentously difficult and profoundly interesting investigation, here sketched in barest outline, is that the solar system is stable: that is to say, that if disturbed a little it will oscillate and return to its old state; whereas if it were unstable the slightest disturbance would tend to accumulate, and would sooner or later bring about a catastrophe. a hanging pendulum is stable, and oscillates about a mean position; its motion is periodic. a top-heavy load balanced on a point is unstable. all the changes of the solar system are periodic, _i.e._ they repeat themselves at regular intervals, and they never exceed a certain moderate amount. the period is something enormous. they will not have gone through all their changes until a period of 2,000,000 years has elapsed. this is the period of the planetary oscillation: "a great pendulum of eternity which beats ages as our pendulums beat seconds." enormous it seems; and yet we have reason to believe that the earth has existed through many such periods. the two laws of stability discovered and stated by lagrange and laplace i can state, though they may be difficult to understand:- represent the masses of the several planets by m_1, m_2, &c.; their mean distances from the sun (or radii vectores) by r_1, r_2, &c.; the excentricities of their orbits by e_1, e_2, &c.; and the obliquity of the planes of these orbits, reckoned from a single plane of reference or "invariable plane," by [theta]_1, [theta]_2, &c.; then all these quantities (except m) are liable to fluctuate; but, however much they change, an increase for one planet will be accompanied by a decrease for some others; so that, taking all the planets into account, the sum of a set of terms like these, m_1e_1^2 [square root]r_1 + m_2e_2^2 [square root]r_2 + &c., will remain always the same. this is summed up briefly in the following statement: [sigma](me^2 [square root]r) = constant. that is one law, and the other is like it, but with inclination of orbit instead of excentricity, viz.: [sigma](m[theta]^2 [square root]r) = constant. the value of each of these two constants can at any time be calculated. at present their values are small. hence they always were and always will be small; being, in fact, invariable. hence neither _e_ nor _r_ nor [theta] can ever become infinite, nor can their average value for the system ever become zero. the planets may share the given amount of total excentricity and obliquity in various proportions between themselves; but even if it were all piled on to one planet it would not be very excessive, unless the planet were so small a one as mercury; and it would be most improbable that one planet should ever have all the excentricity of the solar system heaped upon itself. the earth, therefore, never has been, nor ever will be, enormously nearer the sun than it is at present: nor can it ever get very much further off. its changes are small and are periodic--an increase is followed by a decrease, like the swing of a pendulum. the above two laws have been called the magna charta of the solar system, and were long supposed to guarantee its absolute permanence. so far as the theory of gravitation carries us, they do guarantee its permanence; but something more remains to be said on the subject in a future lecture (xviii). and now, finally, we come to a sublime speculation, thrown out by laplace, not as the result of profound calculation, like the results hitherto mentioned, not following certainly from the theory of gravitation, or from any other known theory, and therefore not to be accepted as more than a brilliant hypothesis, to be confirmed or rejected as our knowledge extends. this speculation is the "nebular hypothesis." since the time of laplace the nebular hypothesis has had ups and downs of credence, sometimes being largely believed in, sometimes being almost ignored. at the present time it holds the field with perhaps greater probability of ultimate triumph than has ever before seemed to belong to it--far greater than belonged to it when first propounded. it had been previously stated clearly and well by the philosopher kant, who was intensely interested in "the starry heavens" as well as in the "mind of man," and who shewed in connexion with astronomy also a most surprising genius. the hypothesis ought by rights perhaps to be known rather by his name than by that of laplace. the data on which it was founded are these:--every motion in the solar system known at that time took place in one direction, and in one direction only. thus the planets revolve round the sun, all going the same way round; moons revolve round the planets, still maintaining the same direction of rotation, and all the bodies that were known to rotate on their own axis did so with still the same kind of spin. moreover, all these motions take place in or near a single plane. the ancients knew that sun moon and planets all keep near to the ecliptic, within a belt known as the zodiac: none strays away into other parts of the sky. satellites also, and rings, are arranged in or near the same plane; and the plane of diurnal spin, or equator of the different bodies, is but slightly tilted. now all this could not be the result of chance. what could have caused it? is there any connection or common ancestry possible, to account for this strange family likeness? there is no connection now, but there may have been once. must have been, we may almost say. it is as though they had once been parts of one great mass rotating as a whole; for if such a rotating mass broke up, its parts would retain its direction of rotation. but such a mass, filling all space as far as or beyond saturn, although containing the materials of the whole solar system in itself, must have been of very rare consistency. occupying so much bulk it could not have been solid, nor yet liquid, but it might have been gaseous. are there any such gigantic rotating masses of gas in the heaven now? certainly there are; there are the nebulæ. some of the nebulæ are now known to be gaseous, and some of them at least are in a state of rotation. laplace could not have known this for certain, but he suspected it. the first distinctly spiral nebula was discovered by the telescope of lord rosse; and quite recently a splendid photograph of the great andromeda nebula, by our townsman, mr. isaac roberts, reveals what was quite unsuspected--and makes it clear that this prodigious mass also is in a state of extensive and majestic whirl. very well, then, put this problem:--a vast mass of rotating gas is left to itself to cool for ages and to condense as it cools: how will it behave? a difficult mathematical problem, worthy of being attacked to-day; not yet at all adequately treated. there are those who believe that by the complete treatment of such a problem all the history of the solar system could be evolved. [illustration: fig. 80.--lord rosse's drawing of the spiral nebula in canes venatici, with the stub marks of the draughtsman unduly emphasised into features by the engraver.] laplace pictured to himself this mass shrinking and thereby whirling more and more rapidly. a spinning body shrinking in size and retaining its original amount of rotation, as it will unless a brake is applied, must spin more and more rapidly as it shrinks. it has what mathematicians call a constant moment of momentum; and what it loses in leverage, as it shrinks, it gains in speed. the mass is held together by gravitation, every particle attracting every other particle; but since all the particles are describing curved paths, they will tend to fly off tangentially, and only a small excess of the gravitation force over the centrifugal is left to pull the particles in, and slowly to concentrate the nebula. the mutual gravitation of the parts is opposed by the centrifugal force of the whirl. at length a point is reached where the two forces balance. a portion outside a certain line will be in equilibrium; it will be left behind, and the rest must contract without it. a ring is formed, and away goes the inner nucleus contracting further and further towards a centre. after a time another ring will be left behind in the same way, and so on. what happens to these rings? they rotate with the motion they possess when thrown or shrunk off; but will they remain rings? if perfectly regular they may; if there be any irregularity they are liable to break up. they will break into one or two or more large masses, which are ultimately very likely to collide and become one. the revolving body so formed is still a rotating gaseous mass; and it will go on shrinking and cooling and throwing off rings, like the larger nucleus by which it has been abandoned. as any nucleus gets smaller, its rate of rotation increases, and so the rings last thrown off will be spinning faster than those thrown off earliest. the final nucleus or residual central body will be rotating fastest of all. the nucleus of the whole original mass we now see shrunk up into what we call the sun, which is spinning on its axis once every twenty-five days. the rings successively thrown off by it are now the planets--some large, some small--those last thrown off rotating round him comparatively quickly, those outside much more slowly. the rings thrown off by the planetary gaseous masses as they contracted have now become satellites; except one ring which has remained without breaking up, and is to be seen rotating round saturn still. one other similar ring, an abortive attempt at a planet, is also left round the sun (the zone of asteroids). such, crudely and baldly, is the famous nebular hypothesis of laplace. it was first stated, as has been said above, by the philosopher kant, but it was elaborated into much fuller detail by the greatest of french mathematicians and astronomers. the contracting masses will condense and generate great quantities of heat by their own shrinkage; they will at a certain stage condense to liquid, and after a time will begin to cool and congeal with a superficial crust, which will get thicker and thicker; but for ages they will remain hot, even after they have become thoroughly solid. the small ones will cool fastest; the big ones will retain their heat for an immense time. bullets cool quickly, cannon-balls take hours or days to cool, planets take millions of years. our moon may be nearly cold, but the earth is still warm--indeed, very hot inside. jupiter is believed by some observers still to glow with a dull red heat; and the high temperature of the much larger and still liquid mass of the sun is apparent to everybody. not till it begins to scum over will it be perceptibly cooler. [illustration: fig. 81.--saturn.] many things are now known concerning heat which were not known to laplace (in the above paragraph they are only hinted at), and these confirm and strengthen the general features of his hypothesis in a striking way; so do the most recent telescopic discoveries. but fresh possibilities have now occurred to us, tidal phenomena are seen to have an influence then wholly unsuspected, and it will be in a modified and amplified form that the philosopher of next century will still hold to the main features of this famous old nebular hypothesis respecting the origin of the sun and planets--the evolution of the solar system. notes to lecture xii the subject of stellar astronomy was first opened up by sir william herschel, the greatest observing astronomer. _frederick william herschel_ was born in hanover in 1738, and brought up as a musician. came to england in 1756. first saw a telescope in 1773. made a great many himself, and began a survey of the heavens. his sister caroline, born in 1750, came to england in 1772, and became his devoted assistant to the end of his life. uranus discovered in 1781. music finally abandoned next year, and the 40-foot telescope begun. discovered two moons of saturn and two of uranus. reviewed, described, and gauged all the visible heavens. discovered and catalogued 2,500 nebulæ and 806 double stars. speculated concerning the milky way, the nebulosity of stars, the origin and growth of solar systems. discovered that the stars were in motion, not fixed, and that the sun as one of them was journeying towards a point in the constellation hercules. died in 1822, eighty-four years old. caroline herschel discovered eight comets, and lived on to the age of ninety-eight. lecture xii herschel and the motion of the fixed stars we may admit, i think, that, with a few notable exceptions, the work of the great men we have been recently considering was rather to complete and round off the work of newton, than to strike out new and original lines. this was the whole tendency of eighteenth century astronomy. it appeared to be getting into an adult and uninteresting stage, wherein everything could be calculated and predicted. labour and ingenuity, and a severe mathematical training, were necessary to work out the remote consequences of known laws, but nothing fresh seemed likely to turn up. consequently men's minds began turning in other directions, and we find chemistry and optics largely studied by some of the greatest minds, instead of astronomy. but before the century closed there was destined to arise one remarkable exception--a man who was comparatively ignorant of that which had been done before--a man unversed in mathematics and the intricacies of science, but who possessed such a real and genuine enthusiasm and love of nature that he overcame the force of adverse circumstances, and entering the territory of astronomy by a by-path, struck out a new line for himself, and infused into the science a healthy spirit of fresh life and activity. this man was william herschel. "the rise of herschel," says miss clerke, "is the one conspicuous anomaly in the otherwise somewhat quiet and prosy eighteenth century. it proved decisive of the course of events in the nineteenth. it was unexplained by anything that had gone before, yet all that came after hinged upon it. it gave a new direction to effort; it lent a fresh impulse to thought. it opened a channel for the widespread public interest which was gathering towards astronomical subjects to flow in." herschel was born at hanover in 1738, the son of an oboe player in a military regiment. the father was a good musician, and a cultivated man. the mother was a german _frau_ of the period, a strong, active, business-like woman, of strong character and profound ignorance. herself unable to write, she set her face against learning and all new-fangled notions. the education of the sons she could not altogether control, though she lamented over it, but the education of her two daughters she strictly limited to cooking, sewing, and household management. these, however, she taught them well. it was a large family, and william was the fourth child. we need only remember the names of his younger brother alexander, and of his much younger sister caroline. they were all very musical--the youngest boy was once raised upon a table to play the violin at a public performance. the girls were forbidden to learn music by their mother, but their father sometimes taught them a little on the sly. alexander was besides an ingenious mechanician. at the age of seventeen, william became oboist to the hanoverian guards, shortly before the regiment was ordered to england. two years later he removed himself from the regiment, with the approval of his parents, though probably without the approbation or consent of the commanding officer, by whom such removal would be regarded as simple desertion, which indeed it was; and george iii. long afterwards handed him an official pardon for it. at the age of nineteen, he was thus launched in england with an outfit of some french, latin, and english, picked up by himself; some skill in playing the hautboy, the violin, and the organ, as taught by his father; and some good linen and clothing, and an immense stock of energy, provided by his mother. he lived as musical instructor to one or two militia bands in yorkshire, and for three years we hear no more than this of him. but, at the end of that time, a noted organist, dr. miller, of durham, who had heard his playing, proposed that he should come and live with him and play at concerts, which he was very glad to do. he next obtained the post of organist at halifax; and some four or five years later he was invited to become organist at the octagon chapel in bath, and soon led the musical life of that then very fashionable place. about this time he went on a short visit to his family at hanover, by all of whom he was very much beloved, especially by his young sister caroline, who always regarded him as specially her own brother. it is rather pitiful, however, to find that her domestic occupations still unfairly repressed and blighted her life. she says:- "of the joys and pleasures which all felt at this long-wished-for meeting with my--let me say my dearest--brother, but a small portion could fall to my share; for with my constant attendance at church and school, besides the time i was employed in doing the drudgery of the scullery, it was but seldom i could make one in the group when the family were assembled together." while at bath he wrote many musical pieces--glees, anthems, chants, pieces for the harp, and an orchestral symphony. he taught a large number of pupils, and lived a hard and successful life. after fourteen hours or so spent in teaching and playing, he would retire at night to instruct his mind with a study of mathematics, optics, italian, or greek, in all of which he managed to make some progress. he also about this time fell in with some book on astronomy. in 1763 his father was struck with paralysis, and two years later he died. william then proposed that alexander should come over from hanover and join him at bath, which was done. next they wanted to rescue their sister caroline from her humdrum existence, but this was a more difficult matter. caroline's journal gives an account of her life at this time that is instructive. here are a few extracts from it:- "my father wished to give me something like a polished education, but my mother was particularly determined that it should be a rough, but at the same time a useful one; and nothing further she thought was necessary but to send me two or three months to a sempstress to be taught to make household linen.... "my mother would not consent to my being taught french, ... so all my father could do for me was to indulge me (and please himself) sometimes with a short lesson on the violin, when my mother was either in good humour or out of the way.... she had cause for wishing me not to know more than was necessary for being useful in the family; for it was her certain belief that my brother william would have returned to his country, and my eldest brother not have looked so high, if they had had a little less learning." however, seven years after the death of their father, william went over to germany and returned to england in triumph, bringing caroline with him: she being then twenty-two. so now began a busy life in bath. for caroline the work must have been tremendous. for, besides having to learn singing, she had to learn english. she had, moreover, to keep accounts and do the marketing. when the season at bath was over, she hoped to get rather more of her brother william's society; but he was deep in optics and astronomy, used to sleep with the books under his pillow, read them during meals, and scarcely ever thought of anything else. he was determined to see for himself all the astronomical wonders; and there being a small gregorian reflector in one of the shops, he hired it. but he was not satisfied with this, and contemplated making a telescope 20 feet long. he wrote to opticians inquiring the price of a mirror suitable, but found there were none so large, and that even the smaller ones were beyond his means. nothing daunted, he determined to make some for himself. alexander entered into his plans: tools, hones, polishers, and all sorts of rubbish were imported into the house, to the sister's dismay, who says:-[illustration: fig. 82.--principle of newtonian reflector.] "and then, to my sorrow, i saw almost every room turned into a workshop. a cabinet-maker making a tube and stands of all descriptions in a handsomely furnished drawing-room; alex. putting up a huge turning-machine (which he had brought in the autumn from bristol, where he used to spend the summer) in a bed-room, for turning patterns, grinding glasses, and turning eye-pieces, &c. at the same time music durst not lie entirely dormant during the summer, and my brother had frequent rehearsals at home." finally, in 1774, at the age of thirty-six, he had made himself a 5-1/2-foot telescope, and began to view the heavens. so attached was he to the instrument that he would run from the concert-room between the parts, and take a look at the stars. he soon began another telescope, and then another. he must have made some dozen different telescopes, always trying to get them bigger and bigger; at last he got a 7-foot and then a 10-foot instrument, and began a systematic survey of the heavens; he also began to communicate his results to the royal society. he now took a larger house, with more room for workshops, and a grass plot for a 20-foot telescope, and still he went on grinding mirrors--literally hundreds of them. i read another extract from the diary of his sister, who waited on him and obeyed him like a spaniel:- "my time was taken up with copying music and practising, besides attendance on my brother when polishing, since by way of keeping him alive i was constantly obliged to feed him by putting the victuals by bits into his mouth. this was once the case when, in order to finish a 7-foot mirror, he had not taken his hands from it for sixteen hours together. in general he was never unemployed at meals, but was always at those times contriving or making drawings of whatever came in his mind. generally i was obliged to read to him whilst he was at the turning-lathe, or polishing mirrors--_don quixote_, _arabian nights' entertainments_, the novels of sterne, fielding, &c.; serving tea and supper without interrupting the work with which he was engaged, ... and sometimes lending a hand. i became, in time, as useful a member of the workshop as a boy might be to his master in the first year of his apprenticeship.... but as i was to take a part the next year in the oratorios, i had, for a whole twelvemonth, two lessons per week from miss fleming, the celebrated dancing-mistress, to drill me for a gentlewoman (god knows how she succeeded). so we lived on without interruption. my brother alex. was absent from bath for some months every summer, but when at home he took much pleasure in executing some turning or clockmaker's work for his brother." the music, and the astronomy, and the making of telescopes, all went on together, each at high pressure, and enough done in each to satisfy any ordinary activity. but the herschels knew no rest. grinding mirrors by day, concerts and oratorios in the evening, star-gazing at night. it is strange his health could stand it. the star-gazing, moreover, was no _dilettante_ work; it was based on a serious system--a well thought out plan of observation. it was nothing less than this--to pass the whole heavens steadily and in order through the telescope, noting and describing and recording every object that should be visible, whether previously known or unknown. the operation is called sweeping; but it is not a rapid passage from one object to another, as the term might suggest; it is a most tedious business, and consists in following with the telescope a certain field of view for some minutes, so as to be sure that nothing is missed, then shifting it to the next overlapping field, and watching again. and whatever object appears must be scrutinized anxiously to see what there is peculiar about it. if a star, it may be double, or it may be coloured, or it may be nebulous; or again it may be variable, and so its brightness must be estimated in order to compare with a subsequent observation. four distinct times in his life did herschel thus pass the whole visible heavens under review; and each survey occupied him several years. he discovered double stars, variable stars, nebulæ, and comets; and mr. william herschel, of bath, the amateur astronomer, was gradually emerging from his obscurity, and becoming a known man. tuesday, the 13th of march, 1781, is a date memorable in the annals of astronomy. "on this night," he writes to the royal society, "in examining the small stars near _[eta]_ geminorum, i perceived one visibly larger than the rest. struck with its uncommon appearance, i compared it to _[eta]_ geminorum and another star, and finding it so much larger than either, i suspected it to be a comet." the "comet" was immediately observed by professional astronomers, and its orbit was computed by some of them. it was thus found to move in nearly a circle instead of an elongated ellipse, and to be nearly twice as far from the sun as saturn. it was no comet, it was a new planet; more than 100 times as big as the earth, and nearly twice as far away as saturn. it was presently christened "uranus." this was a most striking discovery, and the news sped over europe. to understand the interest it excited we must remember that such a discovery was unique. since the most ancient times of which men had any knowledge, the planets mercury, venus, mars, jupiter, saturn, had been known, and there had been no addition to their number. galileo and others had discovered satellites indeed, but a new primary planet was an entire and utterly unsuspected novelty. one of the most immediate consequences of the event was the discovery of herschel himself. the royal society made him a fellow the same year. the university of oxford dubbed him a doctor; and the king sent for him to bring his telescope and show it at court. so to london and windsor he went, taking with him his best telescope. maskelyne, the then astronomer-royal, compared it with the national one at greenwich, and found herschel's home-made instrument far the better of the two. he had a stand made after herschel's pattern, but was so disgusted with his own instrument now that he scarcely thought it worthy of the stand when it was made. at windsor, george iii. was very civil, and mr. herschel was in great request to show the ladies of the court saturn and other objects of interest. mr. herschel exhibited a piece of worldly wisdom under these circumstances, that recalls faintly the behaviour of tycho brahé under similar circumstances. the evening when the exhibition was to take place threatened to become cloudy and wet, so herschel rigged up an artificial saturn, constructed of card and tissue paper, with a lamp behind it, in the distant wall of a garden; and, when the time came, his new titled friends were regaled with a view of this imitation saturn through the telescope--the real one not being visible. they went away much pleased. he stayed hovering between windsor and greenwich, and uncertain what was to be the outcome of all this regal patronizing. he writes to his sister that he would much rather be back grinding mirrors at bath. and she writes begging him to come, for his musical pupils were getting impatient. they had to get the better of their impatience, however, for the king ultimately appointed him astronomer or rather telescope-maker to himself, and so caroline and the whole household were sent for, and established in a small house at datchet. from being a star-gazing musician, herschel thus became a practical astronomer. henceforth he lived in his observatory; only on wet and moonlight nights could he be torn away from it. the day-time he devoted to making his long-contemplated 20-foot telescope. not yet, however, were all their difficulties removed. the house at datchet was a tumble-down barn of a place, chosen rather as a workshop and observatory than as a dwelling-house. and the salary allowed him by george iii. was scarcely a princely one. it was, as a matter of fact, £200 a year. the idea was that he would earn his living by making telescopes, and so indeed he did. he made altogether some hundreds. among others, four for the king. but this eternal making of telescopes for other people to use or play with was a weariness to the flesh. what he wanted was to observe, observe, observe. sir william watson, an old friend of his, and of some influence at court, expressed his mind pretty plainly concerning herschel's position; and as soon as the king got to understand that there was anything the matter, he immediately offered £2,000 for a gigantic telescope to be made for herschel's own use. nothing better did he want in life. the whole army of carpenters and craftsmen resident in datchet were pressed into the service. furnaces for the speculum metal were built, stands erected, and the 40-foot telescope fairly begun. it cost £4,000 before it was finished, but the king paid the whole. [illustration: fig. 83.--herschel's 40-foot telescope.] with it he discovered two more satellites to saturn (five hitherto had been known), and two moons to his own planet uranus. these two are now known as oberon and titania. they were not seen again till some forty years after, when his son, sir john herschel, reobserved them. and in 1847, mr. lassell, at his house, "starfield," near liverpool, discovered two more, called ariel and umbriel, making the number four, as now known. mr. lassell also discovered, with a telescope of his own making, an eighth satellite of saturn--hyperion--and a satellite to neptune. a letter from a foreign astronomer about this period describes herschel and his sister's method of work:- "i spent the night of the 6th of january at herschel's, in datchet, near windsor, and had the good luck to hit on a fine evening. he has his 20-foot newtonian telescope in the open air, and mounted in his garden very simply and conveniently. it is moved by an assistant, who stands below it.... near the instrument is a clock regulated to sidereal time.... in the room near it sits herschel's sister, and she has flamsteed's atlas open before her. as he gives her the word, she writes down the declination and right ascension, and the other circumstances of the observation. in this way herschel examines the whole sky without omitting the least part. he commonly observes with a magnifying power of one hundred and fifty, and is sure that after four or five years he will have passed in review every object above our horizon. he showed me the book in which his observations up to this time are written, and i am astonished at the great number of them. each sweep covers 2° 15' in declination, and he lets each star pass at least three times through the field of his telescope, so that it is impossible that anything can escape him. he has already found about 900 double stars, and almost as many nebulæ. i went to bed about one o'clock, and up to that time he had found that night four or five new nebulæ. the thermometer in the garden stood at 13° fahrenheit; but, in spite of this, herschel observes the whole night through, except that he stops every three or four hours and goes into the room for a few moments. for some years herschel has observed the heavens every hour when the weather is clear, and this always in the open air, because he says that the telescope only performs well when it is at the same temperature as the air. he protects himself against the weather by putting on more clothing. he has an excellent constitution, and thinks about nothing else in the world but the celestial bodies. he has promised me in the most cordial way, entirely in the service of astronomy, and without thinking of his own interest, to see to the telescopes i have ordered for european observatories, and he will himself attend to the preparation of the mirrors." [illustration: _painted by abbott._ _engraved by ryder._ fig. 84.--william herschel. _from an original picture in the possession of_ wm. watson, m.d., f.r.s.] in 1783, herschel married an estimable lady who sympathized with his pursuits. she was the only daughter of a city magnate, so his pecuniary difficulties, such as they were (they were never very troublesome to him), came to an end. they moved now into a more commodious house at slough. their one son, afterwards the famous sir john herschel, was born some nine years later. but the marriage was rather a blow to his devoted sister: henceforth she lived in lodgings, and went over at night-time to help him observe. for it must be remarked that this family literally turned night into day. whatever sleep they got was in the day-time. every fine night without exception was spent in observing: and the quite incredible fierceness of the pursuit is illustrated, as strongly as it can be, by the following sentence out of caroline's diary, at the time of the move from datchet to slough: "the last night at datchet was spent in sweeping till daylight, and by the next evening the telescope stood ready for observation at slough." caroline was now often allowed to sweep with a small telescope on her own account. in this way she picked up a good many nebulæ in the course of her life, and eight comets, four of which were quite new, and one of which, known since as encke's comet, has become very famous. the work they got through between them is something astonishing. he made with his own hands 430 parabolic mirrors for reflecting telescopes, besides a great number of complete instruments. he was forty-two when he began contributing to the royal society; yet before he died he had sent them sixty-nine long and elaborate treatises. one of these memoirs is a catalogue of 1000 nebulæ. fifteen years after he sends in another 1000; and some years later another 500. he also discovered 806 double stars, which he proved were really corrected from the fact that they revolved round each other (p. 309). he lived to see some of them perform half a revolution. for him the stars were not fixed: they moved slowly among themselves. he detected their proper motions. he passed the whole northern firmament in review four distinct times; counted the stars in 3,400 gauge-fields, and estimated the brightness of hundreds of stars. he also measured as accurately as he could their proper motions, devising for this purpose the method which still to this day remains in use. and what is the outcome of it all? it is not uranus, nor the satellites, nor even the double stars and the nebulæ considered as mere objects: it is the beginning of a science of the stars. [illustration: fig. 85.--caroline herschel. _from a drawing from life, by_ george müller, 1847.] hitherto the stars had only been observed for nautical and practical purposes. their times of rising and southing and setting had been noted; they had been treated as a clock or piece of dead mechanism, and as fixed points of reference. all the energies of astronomers had gone out towards the solar system. it was the planets that had been observed. tycho had observed and tabulated their positions. kepler had found out some laws of their motion. galileo had discovered their peculiarities and attendants. newton and laplace had perceived every detail of their laws. but for the stars--the old ptolemaic system might still have been true. they might still be mere dots in a vast crystalline sphere, all set at about one distance, and subservient to the uses of the earth. herschel changed all this. instead of sameness, he found variety; instead of uniformity of distance, limitless and utterly limitless fields and boundless distances; instead of rest and quiescence, motion and activity; instead of stagnation, life. [illustration: fig. 86.--the double-double star [epsilon] lyræ as seen under three different powers.] yes, that is what herschel discovered--the life and activity of the whole visible universe. no longer was our little solar system to be the one object of regard, no longer were its phenomena to be alone interesting to man. with herschel every star was a solar system. and more than that: he found suns revolving round suns, at distances such as the mind reels at, still obeying the same law of gravitation as pulls an apple from a tree. he tried hard to estimate the distance of the stars from the earth, but there he failed: it was too hopeless a problem. it was solved some time after his death by bessel, and the distances of many stars are now known but these distances are awful and unspeakable. our distance from the sun shrinks up into a mere speck--the whole solar system into a mere unit of measurement, to be repeated hundreds of thousands of times before we reach the stars. yet their motion is visible--yes, to very accurate measurement quite plain. one star, known as 61 cygni, was then and is now rushing along at the rate of 100 miles every second. not that you must imagine that this makes any obvious and apparent change in its position. no, for all ordinary and practical purposes they are still fixed stars; thousands of years will show us no obvious change; "adam" saw precisely the same constellations as we do: it is only by refined micrometric measurement with high magnifying power that their flight can be detected. but the sun is one of the stars--not by any means a specially large or bright one; sirius we now know to be twenty times as big as the sun. the sun is one of the stars: then is it at rest? herschel asked this question and endeavoured to answer it. he succeeded in the most astonishing manner. it is, perhaps, his most remarkable discovery, and savours of intuition. this is how it happened. with imperfect optical means and his own eyesight to guide him, he considered and pondered over the proper motion of the stars as he had observed it, till he discovered a kind of uniformity running through it all. mixed up with irregularities and individualities, he found that in a certain part of the heavens the stars were on the whole opening out--separating slowly from each other; on the opposite side of the heavens they were on the average closing up--getting slightly nearer to each other; while in directions at right angles to this they were fairly preserving their customary distances asunder. now, what is the moral to be drawn from such uniformity of behaviour among unconnected bodies? surely that this part of their motion is only apparent--that it is we who are moving. travelling over a prairie bounded by a belt of trees, we should see the trees in our line of advance opening out, and those behind closing up; we should see in fact the same kind of apparent motion as herschel was able to detect among the stars: the opening out being most marked near the constellation hercules. the conclusion is obvious: the sun, with all its planets, must be steadily moving towards a point in the constellation hercules. the most accurate modern research has been hardly able to improve upon this statement of herschel's. possibly the solar system may ultimately be found to revolve round some other body, but what that is no one knows. all one can tell is the present direction of the majestic motion: since it was discovered it has continued unchanged, and will probably so continue for thousands of years. [illustration: fig. 87.--old drawing of the cluster in hercules.] and, finally, concerning the nebulæ. these mysterious objects exercised a strong fascination for herschel, and many are the speculations he indulges in concerning them. at one time he regards them all as clusters of stars, and the milky way as our cluster; the others he regards as other universes almost infinitely distant; and he proceeds to gauge and estimate the shape of our own universe or galaxy of suns, the milky way. later on, however, he pictures to himself the nebulæ as nascent suns: solar systems before they are formed. some he thinks have begun to aggregate, while some are still glowing gas. [illustration: fig. 88.--old drawing of the andromeda nebula.] he likens the heavens to a garden in which there are plants growing in all manner of different stages: some shooting, some in leaf, some in flower, some bearing seed, some decaying; and thus at one inspection we have before us the whole life-history of the plant. just so he thinks the heavens contain worlds, some old, some dead, some young and vigorous, and some in the act of being formed. the nebulæ are these latter, and the nebulous stars are a further stage in the condensation towards a sun. and thus, by simple observation, he is led towards something very like the nebular hypothesis of laplace; and his position, whether it be true or false, is substantially the same as is held to-day. [illustration: fig. 89.--the great nebula in orion.] we _know_ now that many of the nebulæ consist of innumerable isolated particles and may be spoken of as gas. we know that some are in a state of whirling motion. we know also that such gas left to itself will slowly as it cools condense and shrink, so as to form a central solid nucleus; and also, if it were in whirling motion, that it would send off rings from itself, and that these rings could break up into planets. in two familiar cases the ring has not yet thus aggregated into planet or satellite--the zone of asteroids, and saturn's ring. the whole of this could not have been asserted in herschel's time: for further information the world had to wait. these are the problems of modern astronomy--these and many others, which are the growth of this century, aye, and the growth of the last thirty or forty, and indeed of the last ten years. even as i write, new and very confirmatory discoveries are being announced. the milky way _does_ seem to have some affinity with our sun. and the chief stars of the constellation of orion constitute another family, and are enveloped in the great nebula, now by photography perceived to be far greater than had ever been imagined. what is to be the outcome of it all i know not; but sure i am of this, that the largest views of the universe that we are able to frame, and the grandest manner of its construction that we can conceive, are certain to pale and shrink and become inadequate when confronted with the truth. notes to lecture xiii bode's law.--write down the series 0, 3, 6, 12, 24, 48, &c.; add 4 to each, and divide by 10; you get the series: ·4 ·7 1·0 1·6 2·8 5·2 10·0 19·6 38·8 mercury venus earth mars --- jupiter saturn uranus ---numbers which very fairly represent the distances of the then known planets from the sun in the order specified. ceres was discovered on the 1st of january, 1801, by piazzi; pallas in march, 1802, by olbers; juno in 1804, by harding; and vesta in 1807, by olbers. no more asteroids were discovered till 1845, but there are now several hundreds known. their diameters range from 500 to 20 miles. neptune was discovered from the perturbations of uranus by sheer calculation, carried on simultaneously and independently by leverrier in paris, and adams in cambridge. it was first knowingly seen by galle, of berlin, on the 23rd of september, 1846. lecture xiii the discovery of the asteroids up to the time of herschel, astronomical interest centred on the solar system. since that time it has been divided, and a great part of our attention has been given to the more distant celestial bodies. the solar system has by no means lost its interest--it has indeed gained in interest continually, as we gain in knowledge concerning it; but in order to follow the course of science it will be necessary for us to oscillate to and fro, sometimes attending to the solar system--the planets and their satellites--sometimes extending our vision to the enormously more distant stellar spaces. those who have read the third lecture in part i. will remember the speculation in which kepler indulged respecting the arrangements of the planets, the order in which they succeeded one another in space, and the law of their respective distances from the sun; and his fanciful guess about the five regular solids inscribed and circumscribed about their orbits. the rude coincidences were, however, accidental, and he failed to discover any true law. no thoroughly satisfactory law is known at the present day. and yet, if the nebular hypothesis or anything like it be true, there must be some law to be discovered hereafter, though it may be a very complicated one. an empirical relation is, however, known: it was suggested by tatius, and published by bode, of berlin, in 1772. it is always known as bode's law. bode's law asserts that the distance of each planet is approximately double the distance of the inner adjacent planet from the sun, but that the rate of increase is distinctly slower than this for the inner ones; consequently a better approximation will be obtained by adding a constant to each term of an appropriate geometrical progression. thus, form a doubling series like this, 1-1/2, 3, 6, 12, 24, &c. doubling each time; then add 4 to each, and you get a series which expresses very fairly the relative distances of the successive planets from the sun, except that the number for mercury is rather erroneous, and we now know that at the other extreme the number for neptune is erroneous too. i have stated it in the notes above in a form calculated to give the law every chance, and a form that was probably fashionable after the discovery of uranus; but to call the first term of the doubling series 0 is evidently not quite fair, though it puts mercury's distance right. neptune's distance, however, turns out to be more nearly 30 times the earth's distance than 38·8. the others are very nearly right: compare column d of the table preceding lecture iii. on p. 57, with the numbers in the notes on p. 294. the discovery of uranus a few years afterwards, in 1781, at 19·2 times the earth's distance from the sun, lent great _éclât_ to the law, and seemed to establish its right to be regarded as at least a close approximation to the truth. the gap between mars and jupiter, which had often been noticed, and which kepler filled with a hypothetical planet too small to see, comes into great prominence by this law of bode. so much so, that towards the end of last century an enthusiastic german, von zach, after some search himself for the expected planet, arranged a committee of observing astronomers, or, as he termed it, a body of astronomical detective police, to begin a systematic search for this missing subject of the sun. [illustration: fig. 90.--planetary orbits to scale; showing the asteroidal region between jupiter and mars. (the orbits of satellites are exaggerated.)] in 1800 the preliminaries were settled: the heavens near the zodiac were divided into twenty-four regions, each of which was intrusted to one observer to be swept. meanwhile, however, quite independently of these arrangements in germany, and entirely unknown to this committee, a quiet astronomer in sicily, piazzi, was engaged in making a catalogue of the stars. his attention was directed to a certain region in taurus by an error in a previous catalogue, which contained a star really non-existent. in the course of his scrutiny, on the 1st of january, 1801, he noticed a small star which next evening appeared to have shifted. he watched it anxiously for successive evenings, and by the 24th of january he was quite sure he had got hold of some moving body, not a star: probably, he thought, a comet. it was very small, only of the eighth magnitude; and he wrote to two astronomers (one of them bode himself) saying what he had observed. he continued to observe till the 11th of february, when he was attacked by illness and compelled to cease. his letters did not reach their destination till the end of march. directly bode opened his letter he jumped to the conclusion that this must be the missing planet. but unfortunately he was unable to verify the guess, for the object, whatever it was, had now got too near the sun to be seen. it would not be likely to be out again before september, and by that time it would be hopelessly lost again, and have just as much to be rediscovered as if it had never been seen. mathematical astronomers tried to calculate a possible orbit for the body from the observations of piazzi, but the observed places were so desperately few and close together. it was like having to determine a curve from three points close together. three observations ought to serve,[27] but if they are taken with insufficient interval between them it is extremely difficult to construct the whole circumstances of the orbit from them. all the calculations gave different results, and none were of the slightest use. the difficulty as it turned out was most fortunate. it resulted in the discovery of one of the greatest mathematicians, perhaps the greatest, that germany has ever produced--gauss. he was then a young man of twenty-five, eking out a living by tuition. he had invented but not published several powerful mathematical methods (one of them now known as "the method of least squares"), and he applied them to piazzi's observations. he was thus able to calculate an orbit, and to predict a place where, by the end of the year, the planet should be visible. on the 31st of december of that same year, very near the place predicted by gauss, von zach rediscovered it, and olbers discovered it also the next evening. piazzi called it ceres, after the tutelary goddess of sicily. its distance from the sun as determined by gauss was 2·767 times the earth's distance. bode's law made it 2·8. it was undoubtedly the missing planet. but it was only one hundred and fifty or two hundred miles in diameter--the smallest heavenly body known at the time of its discovery. it revolves the same way as other planets, but the plane of its orbit is tilted 10° to the plane of the ecliptic, which was an exceptionally large amount. very soon, a more surprising discovery followed. olbers, while searching for ceres, had carefully mapped the part of the heavens where it was expected; and in march, 1802, he saw in this place a star he had not previously noticed. in two hours he detected its motion, and in a month he sent his observations to gauss, who returned as answer the calculated orbit. it was distant 2·67, like ceres, and was a little smaller, but it had a very excentric orbit: its plane being tilted 34-1/2°, an extraordinary inclination. this was called pallas. olbers at once surmised that these two planets were fragments of a larger one, and kept an eager look out for other fragments. in two years another was seen, in the course of charting the region of the heavens traversed by ceres and pallas. it was smaller than either, and was called juno. in 1807 the persevering search of olbers resulted in the discovery of another, with a very oblique orbit, which gauss named vesta. vesta is bigger than any of the others, being five hundred miles in diameter, and shines like a star of the sixth magnitude. gauss by this time had become so practised in the difficult computations that he worked out the complete orbit of vesta within ten hours of receiving the observational data from olbers. for many weary years olbers kept up a patient and unremitting search for more of these small bodies, or fragments of the large planet as he thought them; but his patience went unrewarded, and he died in 1840 without seeing or knowing of any more. in 1845 another was found, however, in germany, and a few weeks later two others by mr. hind in england. since then there seems no end to them; numbers have been discovered in america, where professors peters and watson have made a specialty of them, and have themselves found something like a hundred. vesta is the largest--its area being about the same as that of central europe, without russia or spain--and the smallest known is about twenty miles in diameter, or with a surface about the size of kent. the whole of them together do not nearly equal the earth in bulk. the main interest of these bodies to us lies in the question, what is their history? can they have been once a single planet broken up? or are they rather an abortive attempt at a planet never yet formed into one? the question is not _entirely_ settled, but i can tell you which way opinion strongly tends at the present time. imagine a shell travelling in an elliptic orbit round the earth to suddenly explode: the centre of gravity of all its fragments would continue moving along precisely the same path as had been traversed by the centre of the shell before explosion, and would complete its orbit quite undisturbed. each fragment would describe an orbit of its own, because it would be affected by a different initial velocity; but every orbit would be a simple ellipse, and consequently every piece would in time return through its starting-point--viz. the place at which the explosion occurred. if the zone of asteroids had a common point through which they all successively passed, they could be unhesitatingly asserted to be the remains of an exploded planet. but they have nothing of the kind; their orbits are scattered within a certain broad zone--a zone everywhere as broad as the earth's distance from the sun, 92,000,000 miles--with no sort of law indicating an origin of this kind. it must be admitted, however, that the fragments of our supposed shell might in the course of ages, if left to themselves, mutually perturb each other into a different arrangement of orbits from that with which they began. but their perturbations would be very minute, and moreover, on laplace's theory, would only result in periodic changes, provided each mass were rigid. it is probable that the asteroids were at one time not rigid, and hence it is difficult to say what may have happened to them; but there is not the least reason to believe that their present arrangement is derivable in any way from an explosion, and it is certain that an enormous time must have elapsed since such an event if it ever occurred. it is far more probable that they never constituted one body at all, but are the remains of a cloudy ring thrown off by the solar system in shrinking past that point: a small ring after the immense effort which produced jupiter and his satellites: a ring which has aggregated into a multitude of little lumps instead of a few big ones. such an event is not unique in the solar system; there is a similar ring round saturn. at first sight, and to ordinary careful inspection, this differs from the zone of asteroids in being a solid lump of matter, like a quoit. but it is easy to show from the theory of gravitation, that a solid ring could not possibly be stable, but would before long get precipitated excentrically upon the body of the planet. devices have been invented, such as artfully distributed irregularities calculated to act as satellites and maintain stability; but none of these things really work. nor will it do to imagine the rings fluid; they too would destroy each other. the mechanical behaviour of a system of rings, on different hypotheses as to their constitution, has been worked out with consummate skill by clerk maxwell; who finds that the only possible constitution for saturn's assemblage of rings is a multitude of discrete particles each pursuing its independent orbit. saturn's ring is, in fact, a very concentrated zone of minor asteroids, and there is every reason to conclude that the origin of the solar asteroids cannot be very unlike the origin of the saturnian ones. the nebular hypothesis lends itself readily to both. the interlockings and motions of the particles in saturn's rings are most beautiful, and have been worked out and stated by maxwell with marvellous completeness. his paper constituted what is called "the adams prize essay" for 1856. sir george airy, one of the adjudicators (recently astronomer-royal), characterized it as "one of the most remarkable applications of mathematics to physics that i have ever seen." there are several distinct constituent rings in the entire saturnian zone, and each perturbs the other, with the result that they ripple and pulse in concord. the waves thus formed absorb the effect of the mutual perturbations, and prevent an accumulation which would be dangerous to the persistence of the whole. the only effect of gravitational perturbation and of collisions is gradually to broaden out the whole ring, enlarging its outer and diminishing its inner diameter. but if there were any frictional resistance in the medium through which the rings spin, then other effects would slowly occur, which ought to be looked for with interest. so complete and intimate is the way maxwell works out and describes the whole circumstances of the motion of such an assemblage of particles, and so cogent his argument as to the necessity that they must move precisely so, and no otherwise, else the rings would not be stable, that it was a cambridge joke concerning him that he paid a visit to saturn one evening, and made his observations on the spot. notes to lecture xiv the total number of stars in the heavens visible to a good eye is about 5,000. the total number at present seen by telescope is about 50,000,000. the number able to impress a photographic plate has not yet been estimated; but it is enormously greater still. of those which we can see in these latitudes, about 14 are of the first magnitude, 48 of the second, 152 of the third, 313 of the fourth, 854 of the fifth, and 2,010 of the sixth; total, 3,391. the quickest-moving stars known are a double star of the sixth magnitude, called 61 cygni, and one of the seventh magnitude, called groombridge 1830. the velocity of the latter is 200 miles a second. the nearest known stars are 61 cygni and [alpha] centauri. the distance of these from us is about 400,000 times the distance of the sun. their parallax is accordingly half a second of arc. sirius is more than a million times further from us than our sun is, and twenty times as big; many of the brightest stars are at more than double this distance. the distance of arcturus is too great to measure even now. stellar parallax was first securely detected in 1838, by bessel, for 61 cygni. bessel was born in 1784, and died in 1846, shortly before the discovery of neptune. the stars are suns, and are most likely surrounded by planets. one planet belonging to sirius has been discovered. it was predicted by bessel, its position calculated by peters, and seen by alvan clark in 1862. another predicted one, belonging to procyon, has not yet been seen. a velocity of 5 miles a second could carry a projectile right round the earth. a velocity of 7 miles a second would carry it away from the earth, and round the sun. a velocity of 27 miles a second would carry a projectile right out of the solar system never to return. lecture xiv bessel--the distances of the stars, and the discovery of stellar planets we will now leave the solar system for a time, and hastily sketch the history of stellar astronomy from the time of sir william herschel. you remember how greatly herschel had changed the aspect of the heavens for man,--how he had found that none of the stars were really fixed, but were moving in all manner of ways: some of this motion only apparent, much of it real. nevertheless, so enormously distant are they, that if we could be transported back to the days of the old chaldæan astronomers, or to the days of noah, we should still see the heavens with precisely the same aspect as they wear now. only by refined apparatus could any change be discoverable in all those centuries. for all practical purposes, therefore, the stars may still be well called fixed. another thing one may notice, as showing their enormous distances, is that from every planet of the solar system the aspect of the heavens will be precisely the same. inhabitants of mars, or jupiter, or saturn, or uranus, will see exactly the same constellations as we do. the whole dimensions of the solar system shrink up into a speck when so contemplated. and from the stars none of the planetary orbs of our system are visible at all; nothing but the sun is visible, and that merely as a twinkling star, brighter than some, but fainter than many others. the sun and the stars are one. try to realize this distinctly, and keep it in mind. i find it often difficult to drive this idea home. after some talk on the subject a friendly auditor will report, "the lecturer then described the stars, including that greatest and most magnificent of all stars, the sun." it would be difficult more completely to misapprehend the entire statement. when i say the sun is one of the stars, i mean one among the others; we are a long way from them, they are a long way from each other. they need be no more closely packed among each other than we are closely packed among them; except that some of them are double or multiple, and we are not double. it is highly desirable to acquire an intimate knowledge of the constellations and a nodding acquaintance with their principal stars. a description of their peculiarities is dull and uninteresting unless they are at least familiar by name. a little _vivâ voce_ help to begin with, supplemented by patient night scrutiny with a celestial globe or star maps under a tent or shed, is perhaps the easiest way: a very convenient instrument for the purpose of learning the constellations is the form of map called a "planisphere," because it can be made to show all the constellations visible at a given time at a given date, and no others. the greek alphabet also is a thing that should be learnt by everybody. the increased difficulty in teaching science owing to the modern ignorance of even a smattering of greek is becoming grotesque. the stars are named from their ancient grouping into constellations, and by the prefix of a greek letter to the larger ones, and of numerals to the smaller ones. the biggest of all have special arabic names as well. the brightest stars are called of "the first magnitude," the next are of "the second magnitude," and so on. but this arrangement into magnitudes has become technical and precise, and intermediate or fractional magnitudes are inserted. those brighter than the ordinary first magnitude are therefore now spoken of as of magnitude 1/2, for instance, or ·6, which is rather confusing. small telescopic stars are often only named by their numbers in some specified catalogue--a dull but sufficient method. here is a list of the stars visible from these latitudes, which are popularly considered as of the first magnitude. all of them should be familiarly recognized in the heavens, whenever seen. star. constellation. sirius canis major procyon canis minor rigel orion betelgeux orion castor gemini pollux gemini aldebaran taurus arcturus boötes vega lyra capella auriga regulus leo altair aquila fomalhaut southern fish spica virgo [alpha] cygni is a little below the first magnitude. so, perhaps, is castor. in the southern heavens, canopus and [alpha] centauri rank next after sirius in brightness. [illustration: fig. 91.--diagram illustrating parallax.] the distances of the fixed stars had, we know, been a perennial problem, and many had been the attempts to solve it. all the methods of any precision have depended on the copernican fact that the earth in june was 184 million miles away from its position in december, and that accordingly the grouping and aspect of the heavens should be somewhat different when seen from so different a point of view. an apparent change of this sort is called generally parallax; _the_ parallax of a star being technically defined as the angle subtended at the star by the radius of the earth's orbit: that is to say, the angle e[sigma]s; where e is the earth, s the sun, and [sigma] a star (fig. 91). plainly, the further off [sigma] is, the more nearly parallel will the two lines to it become. and the difficulty of determining the parallax was just this, that the more accurately the observations were made, the more nearly parallel did those lines become. the angle was, in fact, just as likely to turn out negative as positive--an absurd result, of course, to be attributed to unavoidable very minute inaccuracies. for a long time absolute methods of determining parallax were attempted; for instance, by observing the position of the star with respect to the zenith at different seasons of the year. and many of these determinations appeared to result in success. hooke fancied he had measured a parallax for vega in this way, amounting to 30" of arc. flamsteed obtained 40" for [gamma] draconis. roemer made a serious attempt by comparing observations of vega and sirius, stars almost the antipodes of each other in the celestial vault; hoping to detect some effect due to the size of the earth's orbit, which should apparently displace them with the season of the year. all these fancied results however, were shown to be spurious, and their real cause assigned, by the great discovery of the aberration of light by bradley. after this discovery it was possible to watch for still outstanding very minute discrepancies; and so the problem of stellar parallax was attacked with fresh vigour by piazzi, by brinkley, and by struve. but when results were obtained, they were traced after long discussion to age and gradual wear of the instrument, or to some other minute inaccuracy. the more carefully the observation was made, the more nearly zero became the parallax--the more nearly infinite the distance of the stars. the brightest stars were the ones commonly chosen for the investigation, and vega was a favourite, because, going near the zenith, it was far removed from the fluctuating and tiresome disturbances of atmospheric refraction. the reason bright stars were chosen was because they were presumably nearer than the others; and indeed a rough guess at their probable distance was made by supposing them to be of the same size as the sun, and estimating their light in comparison with sunlight. by this confessedly unsatisfactory method it had been estimated that sirius must be 140,000 times further away than the sun is, if he be equally big. we now know that sirius is much further off than this; and accordingly that he is much brighter, perhaps sixty times as bright, though not necessarily sixty times as big, as our sun. but even supposing him of the same light-giving power as the sun, his parallax was estimated as 1"·8, a quantity very difficult to be sure of in any absolute determination. relative methods were, however, also employed, and the advantages of one of these (which seems to have been suggested by galileo) so impressed themselves upon william herschel that he made a serious attempt to compass the problem by its means. the method was to take two stars in the same telescopic field and carefully to estimate their apparent angular distance from each other at different seasons of the year. all such disturbances as precession, aberration, nutation, refraction, and the like, would affect them both equally, and could thus be eliminated. if they were at the same distance from the solar system, relative parallax would, indeed, also be eliminated; but if, as was probable, they were at different distances, then they would apparently shift relatively to one another, and the amount of shift, if it could be observed, would measure, not indeed the distance of either from the earth, but their distance from each other. and this at any rate would be a step. it might be completed by similarly treating other stars in the same field, taking them in pairs together. a bright and a faint star would naturally be suitable, because their distances were likely to be unequal; and so herschel fixed upon a number of doublets which he knew of, containing one bright and one faint component. for up to that time it had been supposed that such grouping in occasional pairs or triplets was chance coincidence, the two being optically foreshortened together, but having no real connection or proximity. herschel failed in what he was looking for, but instead of that he discovered the real connection of a number of these doublets, for he found that they were slowly revolving round each other. there are a certain number of merely optical or accidental doublets, but the majority of them are real pairs of suns revolving round each other. this relative method of mapping micrometrically a field of neighbouring stars, and comparing their configuration now and six months hence, was, however, the method ultimately destined to succeed; and it is, i believe, the only method which has succeeded down to the present day. certainly it is the method regularly employed, at dunsink, at the cape of good hope, and everywhere else where stellar parallax is part of the work. between 1830 and 1840 the question was ripe for settlement, and, as frequently happens with a long-matured difficulty, it gave way in three places at once. bessel, henderson, and struve almost simultaneously announced a stellar parallax which could reasonably be accepted. bessel was a little the earliest, and by far the most accurate. his, indeed, was the result which commanded confidence, and to him the palm must be awarded. he was largely a self-taught student, having begun life in a counting-house, and having abandoned business for astronomy. but notwithstanding these disadvantages, he became a highly competent mathematician as well as a skilful practical astronomer. he was appointed to superintend the construction of germany's first great astronomical observatory, that of königsberg, which, by his system, zeal, and genius, he rapidly made a place of the first importance. struve at dorpat, bessel at königsberg, and henderson at the cape of good hope--all of them at newly-equipped observatories--were severally engaged at the same problem. but the russian and german observers had the advantage of the work of one of the most brilliant opticians--i suppose the most brilliant--that has yet appeared: fraunhofer, of munich. an orphan lad, apprenticed to a maker of looking-glasses, and subject to hard struggles and privations in early life, he struggled upwards, and ultimately became head of the optical department of a munich firm of telescope-makers. here he constructed the famous "dorpat refractor" for struve, which is still at work; and designed the "königsberg heliometer" for bessel. he also made a long and most skilful research into the solar spectrum, which has immortalized his name. but his health was broken by early trials, and he died at the age of thirty-nine, while planning new and still more important optical achievements. a heliometer is the most accurate astronomical instrument for relative measurements of position, as a transit circle is the most accurate for absolute determinations. it consists of an equatorial telescope with object-glass cut right across, and each half movable by a sliding movement one past the other, the amount by which the two halves are dislocated being read off by a refined method, and the whole instrument having a multitude of appendages conducive to convenience and accuracy. its use is to act as a micrometer or measurer of small distances.[28] each half of the object-glass gives a distinct image, which may be allowed to coincide or may be separated as occasion requires. if it be the components of a double star that are being examined, each component will in general be seen double, so that four images will be seen altogether; but by careful adjustment it will be possible to arrange that one image of each pair shall be superposed on or coincide with each other, in which case only three images are visible; the amount of dislocation of the halves of the object-glass necessary to accomplish this is what is read off. the adjustment is one that can be performed with extreme accuracy, and by performing it again and again with all possible modifications, an extremely accurate determination of the angular distance between the two components is obtained. [illustration: fig. 92.--heliometer.] bessel determined to apply this beautiful instrument to the problem of stellar parallax; and he began by considering carefully the kind of star for which success was most likely. hitherto the brightest had been most attended to, but bessel thought that quickness of proper motion would be a still better test of nearness. not that either criterion is conclusive as to distance, but there was a presumption in favour of either a very bright or an obviously moving star being nearer than a faint or a stationary one; and as the "bright" criterion had already been often applied without result, he decided to try the other. he had already called attention to a record by piazzi in 1792 of a double star in cygnus whose proper motion was five seconds of arc every year--a motion which caused this telescopic object, 61 cygni, to be known as "the flying star." its motion is not really very perceptible, for it will only have traversed one-third of a lunar diameter in the course of a century; still it was the quickest moving star then known. the position of this interesting double he compared with two other stars which were seen simultaneously in the field of the heliometer, by the method i have described, throughout the whole year 1838; and in the last month of that year he was able to announce with confidence a distinct though very small parallax; substantiating it with a mass of detailed evidence which commanded the assent of astronomers. the amount of it he gave as one-third of a second. we know now that he was very nearly right, though modern research makes it more like half a second.[29] soon afterwards, struve announced a quarter of a second as the parallax of vega, but that is distinctly too great; and henderson announced for [alpha] centauri (then thought to be a double) a parallax of one second, which, if correct, would make it quite the nearest of all the stars, but the result is now believed to be about twice too big. knowing the distance of 61 cygni, we can at once tell its real rate of travel--at least, its rate across our line of sight: it is rather over three million miles a day. now just consider the smallness of the half second of arc, thus triumphantly though only approximately measured. it is the angle subtended by twenty-six feet at a distance of 2,000 miles. if a telescope planted at new york could be directed to a house in england, and be then turned so as to set its cross-wire first on one end of an ordinary room and then on the other end of the same room, it would have turned through half a second, the angle of greatest stellar parallax. or, putting it another way. if the star were as near us as new york is, the sun, on the same scale, would be nine paces off. as twenty-six feet is to the distance of new york, so is ninety-two million miles to the distance of the nearest fixed star. suppose you could arrange some sort of telegraphic vehicle able to carry you from here to new york in the tenth part of a second--_i.e._ in the time required to drop two inches--such a vehicle would carry you to the moon in twelve seconds, to the sun in an hour and a quarter. travelling thus continually, in twenty-four hours you would leave the last member of the solar system behind you, and begin your plunge into the depths of space. how long would it be before you encountered another object? a month, should you guess? twenty years you must journey with that prodigious speed before you reach the nearest star, and then another twenty years before you reach another. at these awful distances from one another the stars are scattered in space, and were they not brilliantly self-luminous and glowing like our sun, they would be hopelessly invisible. i have spoken of 61 cygni as a flying star, but there is another which goes still quicker, a faint star, 1830 in groombridge's catalogue. its distance is far greater than that of 61 cygni, and yet it is seen to move almost as quickly. its actual speed is about 200 miles a second--greater than the whole visible firmament of fifty million stars can control; and unless the universe is immensely larger than anything we can see with the most powerful telescopes, or unless there are crowds of invisible non-luminous stars mixed up with the others, it can only be a temporary visitor to this frame of things; it is rushing from an infinite distance to an infinite distance; it is passing through our visible universe for the first and only time--it will never return. but so gigantic is the extent of visible space, that even with its amazing speed of 200 miles every second, this star will take two or three million years to get out of sight of our present telescopes, and several thousand years before it gets perceptibly fainter than it is now. have we any reason for supposing that the stars we see are all there are? in other words, have we any reason for supposing all celestial objects to be sufficiently luminous to be visible? we have every ground for believing the contrary. every body in the solar system is dull and dark except the sun, though probably jupiter is still red-hot. why may not some of the stars be dark too? the genius of bessel surmised this, and consistently upheld the doctrine that the astronomy of the future would have to concern itself with dark and invisible bodies; he preached "an astronomy of the invisible." moreover he predicted the presence of two such dark bodies--one a companion of sirius, the other of procyon. he noticed certain irregularities in the motions of these stars which he asserted must be caused by their revolving round other bodies in a period of half a century. he announced in 1844 that both sirius and procyon were double stars, but that their companions, though large, were dark, and therefore invisible. no one accepted this view, till peters, in america, found in 1851 that the hypothesis accurately explained the anomalous motion of sirius, and, in fact, indicated an exact place where the companion ought to be. the obscure companion of sirius became now a recognized celestial object, although it had never been seen, and it was held to revolve round sirius in fifty years, and to be about half as big. in 1862, the firm of alvan clark and sons, of new york, were completing a magnificent 18-inch refractor, and the younger clark was trying it on sirius, when he said: "why, father, the star has a companion!" the elder clark also looked, and sure enough there was a faint companion due east of the bright star, and in just the position required by theory. not that the clarks knew anything about the theory. they were keen-sighted and most skilful instrument-makers, and they made the discovery by accident. after it had once been seen, it was found that several of the large telescopes of the world were able to show it. it is half as big, but it only gives 1/10000th part of the light that sirius gives. no doubt it shines partly with a borrowed light and partly with a dull heat of its own. it is a real planet, but as yet too hot to live on. it will cool down in time, as our earth has cooled and as jupiter is cooling, and no doubt become habitable enough. it does revolve round sirius in a period of 49·4 years--almost exactly what bessel assigned to it. but bessel also assigned a dark companion to procyon. it and its luminous neighbour are considered to revolve round each other in a period of forty years, and astronomers feel perfectly assured of its existence, though at present it has not been seen by man. lecture xv the discovery of neptune we approach to-night perhaps the greatest, certainly the most conspicuous, triumphs of the theory of gravitation. the explanation by newton of the observed facts of the motion of the moon, the way he accounted for precession and nutation and for the tides, the way in which laplace explained every detail of the planetary motions--these achievements may seem to the professional astronomer equally, if not more, striking and wonderful; but of the facts to be explained in these cases the general public are necessarily more or less ignorant, and so no beauty or thoroughness of treatment appeals to them, nor can excite their imaginations. but to predict in the solitude of the study, with no weapons other than pen, ink, and paper, an unknown and enormously distant world, to calculate its orbit when as yet it had never been seen, and to be able to say to a practical astronomer, "point your telescope in such a direction at such a time, and you will see a new planet hitherto unknown to man"--this must always appeal to the imagination with dramatic intensity, and must awaken some interest in almost the dullest. prediction is no novelty in science; and in astronomy least of all is it a novelty. thousands of years ago, thales, and others whose very names we have forgotten, could predict eclipses with some certainty, though with only rough accuracy. and many other phenomena were capable of prediction by accumulated experience. we have seen, for instance (coming to later times), how a gap between mars and jupiter caused a missing planet to be suspected and looked for, and to be found in a hundred pieces. we have seen, also, how the abnormal proper-motion of sirius suggested to bessel the existence of an unseen companion. and these last instances seem to approach very near the same class of prediction as that of the discovery of neptune. wherein, then, lies the difference? how comes it that some classes of prediction--such as that if you put your finger in fire it will get burnt--are childishly easy and commonplace, while others excite in the keenest intellects the highest feelings of admiration? mainly, the difference lies, first, in the grounds on which the prediction is based; second, on the difficulty of the investigation whereby it is accomplished; third, in the completeness and the accuracy with which it can be verified. in all these points, the discovery of neptune stands out pre-eminently among the verified predictions of science, and the circumstances surrounding it are of singular interest. * * * * * in 1781, sir william herschel discovered the planet uranus. now you know that three distinct observations suffice to determine the orbit of a planet completely, and that it is well to have the three observations as far apart as possible so as to minimize the effects of minute but necessary errors of observation. (see p. 298.) directly uranus was found, therefore, old records of stellar observations were ransacked, with the object of discovering whether it had ever been unwittingly seen before. if seen, it had been thought of course to be a star (for it shines like a star of the sixth magnitude, and can therefore be just seen without a telescope if one knows precisely where to look for it, and if one has good sight), but if it had been seen and catalogued as a star it would have moved from its place, and the catalogue would by that entry be wrong. the thing to detect, therefore, was errors in the catalogues: to examine all entries, and see if the stars entered actually existed, or were any of them missing. if a wrong entry were discovered, it might of course have been due to some clerical error, though that is hardly probable considering the care taken over these things, or it might have been some tailless comet or other, or it might have been the newly found planet. so the next thing was to calculate backwards, and see if by any possibility the planet could have been in that place at that time. examined in this way the tabulated observations of flamsteed showed that he had unwittingly observed uranus five distinct times, the first time in 1690, nearly a century before herschel discovered its true nature. but more remarkable still, le monnier, of paris, had observed it eight times in one month, cataloguing it each time as a different star. if only he had reduced and compared his observations, he would have anticipated herschel by twelve years. as it was, he missed it altogether. it was seen once by bradley also. altogether it had been seen twenty times. these old observations of flamsteed and those of le monnier, combined with those made after herschel's discovery, were very useful in determining an exact orbit for the new planet, and its motion was considered thoroughly known. it was not an _exact_ ellipse, of course: none of the planets describe _exact_ ellipses--each perturbs all the rest, and these small perturbations must be taken into account, those of jupiter and saturn being by far the most important. for a time uranus seemed to travel regularly and as expected, in the orbit which had been calculated for it; but early in the present century it began to be slightly refractory, and by 1820 its actual place showed quite a distinct discrepancy from its position as calculated with the aid of the old observations. it was at first thought that this discrepancy must be due to inaccuracies in the older observations, and they were accordingly rejected, and tables prepared for the planet based on the newer and more accurate observations only. but by 1830 it became apparent that it would not accurately obey even these. the error amounted to some 20". by 1840 it was as much as 90', or a minute and a half. this discrepancy is quite distinct, but still it is very small, and had two objects been in the heavens at once, the actual uranus and the theoretical uranus, no unaided eye could possibly have distinguished them or detected that they were other than a single star. [illustration: fig. 93.--perturbations of uranus. the chance observations by flamsteed, by le monnier, and others, are plotted in this diagram, as well as the modern determinations made after herschel had discovered the nature of the planet. the decades are laid off horizontally. vertical distance represents the difference between observed and subsequently calculated longitudes--in other words, the principal perturbations caused by neptune. to show the scale, a number of standard things are represented too by lengths measured upwards from the line of time, viz: the smallest quantity perceptible to the naked eye,--the maximum angle of aberration, of nutation, and of stellar parallax; though this last is too small to be properly indicated. the perturbations are much bigger than these; but compared with what can be seen without a telescope they are small--the distance between the component pairs of [epsilon] lyræ (210") (see fig. 86, page 288), which a few keen-eyed persons can see as a simple double star, being about twice the greatest perturbation.] the diagram shows all the irregularities plotted in the light of our present knowledge; and, to compare with their amounts, a few standard things are placed on the same scale, such as the smallest interval capable of being detected with the unaided eye, the distance of the component stars in [epsilon] lyræ, the constants of aberration, of nutation, and of stellar parallax. the errors of uranus therefore, though small, were enormously greater than things which had certainly been observed; there was an unmistakable discrepancy between theory and observation. some cause was evidently at work on this distant planet, causing it to disagree with its motion as calculated according to the law of gravitation. some thought that the exact law of gravitation did not apply to so distant a body. others surmised the presence of some foreign and unknown body, some comet, or some still more distant planet perhaps, whose gravitative attraction for uranus was the cause of the whole difficulty--some perturbations, in fact, which had not been taken into account because of our ignorance of the existence of the body which caused them. but though such an idea was mentioned among astronomers, it was not regarded with any special favour, and was considered merely as one among a number of hypotheses which could be suggested as fairly probable. it is perfectly right not to attach much importance to unelaborated guesses. not until the consequences of an hypothesis have been laboriously worked out--not until it can be shown capable of producing the effect quantitatively as well as qualitatively--does its statement rise above the level of a guess, and attain the dignity of a theory. a later stage still occurs when the theory has been actually and completely verified by agreement with observation. now the errors in the motion of uranus, _i.e._ the discrepancy between its observed and calculated longitudes--all known disturbing causes, such as jupiter and saturn, being allowed for--are as follows (as quoted by dr. haughton) in seconds of arc:- ancient observations (casually made, as of a star). flamsteed 1690 +61·2 " 1712 +92·7 " 1715 +73·8 le monnier 1750 -47·6 bradley 1753 -39·5 mayer 1756 -45·7 le monnier 1764 -34·9 " 1769 -19·3 " 1771 -2·3 modern observations. 1780 +3·46 1783 +8·45 1786 +12·36 1789 +19·02 1801 +22·21 1810 +23·16 1822 +20·97 1825 +18·16 1828 +10·82 1831 -3·98 1834 -20·80 1837 -42·66 1840 -66·64 these are the numbers plotted in the above diagram (fig. 92), where h marks the discovery of the planet and the beginning of its regular observation. something was evidently the matter with the planet. if the law of gravitation held exactly at so great a distance from the sun, there must be some perturbing force acting on it besides all those known ones which had been fully taken into account. could it be an outer planet? the question occurred to several, and one or two tried if they could solve the problem, but were soon stopped by the tremendous difficulties of calculation. the ordinary problem of perturbation is difficult enough: given a disturbing planet in such and such a position, to find the perturbations it produces. this problem it was that laplace worked out in the _mécanique céleste_. but the inverse problem: given the perturbations, to find the planet which causes them--such a problem had never yet been attacked, and by only a few had its possibility been conceived. bessel made preparations for trying what he could do at it in 1840, but he was prevented by fatal illness. in 1841 the difficulties of the problem presented by these residual perturbations of uranus excited the imagination of a young student, an undergraduate of st. john's college, cambridge--john couch adams by name--and he determined to have a try at it as soon as he was through his tripos. in january, 1843, he graduated as senior wrangler, and shortly afterwards he set to work. in less than two years he reached a definite conclusion; and in october, 1845, he wrote to the astronomer-royal, at greenwich, professor airy, saying that the perturbations of uranus would be explained by assuming the existence of an outer planet, which he reckoned was now situated in a specified latitude and longitude. we know now that had the astronomer-royal put sufficient faith in this result to point his big telescope to the spot indicated and commence sweeping for a planet, he would have detected it within 1-3/4° of the place assigned to it by mr. adams. but any one in the position of the astronomer-royal knows that almost every post brings an absurd letter from some ambitious correspondent or other, some of them having just discovered perpetual motion, or squared the circle, or proved the earth flat, or discovered the constitution of the moon, or of ether, or of electricity; and out of this mass of rubbish it requires great skill and patience to detect such gems of value as there may be. now this letter of mr. adams's was indeed a jewel of the first water, and no doubt bore on its face a very different appearance from the chaff of which i have spoken; but still mr. adams was an unknown man: he had graduated as senior wrangler it is true, but somebody must graduate as senior wrangler every year, and every year by no means produces a first-rate mathematician. those behind the scenes, as professor airy of course was, having been a senior wrangler himself, knew perfectly well that the labelling of a young man on taking his degree is much more worthless as a testimony to his genius and ability than the general public are apt to suppose. was it likely that a young and unknown man should have successfully solved so extremely difficult a problem? it was altogether unlikely. still, he would test him: he would ask for further explanations concerning some of the perturbations which he himself had specially noticed, and see if mr. adams could explain these also by his hypothesis. if he could, there might be something in his theory. if he failed--well, there was an end of it. the questions were not difficult. they concerned the error of the radius vector. mr. adams could have answered them with perfect ease; but sad to say, though a brilliant mathematician, he was not a man of business. he did not answer professor airy's letter. it may to many seem a pity that the greenwich equatoreal was not pointed to the place, just to see whether any foreign object did happen to be in that neighbourhood; but it is no light matter to derange the work of an observatory, and alter the work mapped out for the staff into a sudden sweep for a new planet, on the strength of a mathematical investigation just received by post. if observatories were conducted on these unsystematic and spasmodic principles, they would not be the calm, accurate, satisfactory places they are. of course, if any one could have known that a new planet was to be had for the looking, _any_ course would have been justified; but no one could know this. i do not suppose that mr. adams himself could feel all that confidence in his attempted prediction. so there the matter dropped. mr. adams's communication was pigeon-holed, and remained in seclusion for eight or nine months. meanwhile, and quite independently, something of the same sort was going on in france. a brilliant young mathematician, born in normandy in 1811, had accepted the post of astronomical professor at the école polytechnique, then recently founded by napoleon. his first published papers directed attention to his wonderful powers; and the official head of astronomy in france, the famous arago, suggested to him the unexplained perturbations of uranus as a worthy object for his fresh and well-armed vigour. at once he set to work in a thorough and systematic way. he first considered whether the discrepancies could be due to errors in the tables or errors in the old observations. he discussed them with minute care, and came to the conclusion that they were not thus to be explained away. this part of the work he published in november, 1845. he then set to work to consider the perturbations produced by jupiter and saturn, to see if they had been with perfect accuracy allowed for, or whether some minute improvements could be made sufficient to destroy the irregularities. he introduced several fresh terms into these perturbations, but none of them of sufficient magnitude to do more than slightly lessen the unexplained perturbations. he next examined the various hypotheses that had been suggested to account for them:--was it a failure in the law of gravitation? was it due to the presence of a resisting medium? was it due to some unseen but large satellite? or was it due to a collision with some comet? all these he examined and dismissed for various reasons one after the other. it was due to some steady continuous cause--for instance, some unknown planet. could this planet be inside the orbit of uranus? no, for then it would perturb saturn and jupiter also, and they were not perturbed by it. it must, therefore, be some planet outside the orbit of uranus, and in all probability, according to bode's empirical law, at nearly double the distance from the sun that uranus is. lastly he proceeded to examine where this planet was, and what its orbit must be to produce the observed disturbances. [illustration: fig. 94.--uranus's and neptune's relative positions. the above diagram, drawn to scale by dr. haughton, shows the paths of uranus and neptune, and their positions from 1781 to 1840, and illustrates the _direction_ of their mutual perturbing force. in 1822 the planets were in conjunction, and the force would then perturb the radius vector (or distance from the sun), but not the longitude (or place in orbit). before that date uranus had been hurried along, and after that date it had been retarded, by the pull of neptune, and thus the observed discrepancies from its computed place were produced. the problem was first to disentangle the outstanding perturbations from those which would be caused by jupiter and saturn and all other known causes, and then to assign the place of an outer planet able to produce precisely those perturbations in uranus.] not without failures and disheartening complications was this part of the process completed. this was, after all, the real tug of war. so many unknown quantities: its mass, its distance, its excentricity, the obliquity of its orbit, its position at any time--nothing known, in fact, about the planet except the microscopic disturbance it caused in uranus, some thousand million miles away from it. without going into further detail, suffice it to say that in june, 1846, he published his last paper, and in it announced to the world his theoretical position for the planet. professor airy received a copy of this paper before the end of the month, and was astonished to find that leverrier's theoretical place for the planet was within 1° of the place mr. adams had assigned to it eight months before. so striking a coincidence seemed sufficient to justify a herschelian "sweep" for a week or two. but a sweep for so distant a planet would be no easy matter. when seen in a large telescope it would still only look like a star, and it would require considerable labour and watching to sift it out from the other stars surrounding it. we know that uranus had been seen twenty times, and thought to be a star, before its true nature was by herschel discovered; and uranus is only about half as far away as neptune is. neither in paris nor yet at greenwich was any optical search undertaken; but professor airy wrote to ask m. leverrier the same old question as he had fruitlessly put to mr. adams: did the new theory explain the errors of the radius vector or not? the reply of leverrier was both prompt and satisfactory--these errors were explained, as well as all the others. the existence of the object was then for the first time officially believed in. the british association met that year at southampton, and sir john herschel was one of its sectional presidents. in his inaugural address, on september 10th, 1846, he called attention to the researches of leverrier and adams in these memorable words:- "the past year has given to us the new [minor] planet astræa; it has done more--it has given us the probable prospect of another. we see it as columbus saw america from the shores of spain. its movements have been felt trembling along the far-reaching line of our analysis with a certainty hardly inferior to ocular demonstration." it was about time to begin to look for it. so the astronomer-royal thought on reading leverrier's paper. but as the national telescope at greenwich was otherwise occupied, he wrote to professor challis, at cambridge, to know if he would permit a search to be made for it with the northumberland equatoreal, the large telescope of cambridge university, presented to it by one of the dukes of northumberland. professor challis said he would conduct the search himself; and shortly commenced a leisurely and dignified series of sweeps round about the place assigned by theory, cataloguing all the stars which he observed, intending afterwards to sort out his observations, compare one with another, and find out whether any one star had changed its position; because if it had it must be the planet. he thus, without giving an excessive time to the business, accumulated a host of observations, which he intended afterwards to reduce and sift at his leisure. the wretched man thus actually saw the planet twice--on august 4th and august 12th, 1846--without knowing it. if only he had had a map of the heavens containing telescopic stars down to the tenth magnitude, and if he had compared his observations with this map as they were made, the process would have been easy, and the discovery quick. but he had no such map. nevertheless one was in existence: it had just been completed in that country of enlightened method and industry--germany. dr. bremiker had not, indeed, completed his great work--a chart of the whole zodiac down to stars of the tenth magnitude--but portions of it were completed, and the special region where the new planet was expected happened to be among the portions already just done. but in england this was not known. meanwhile, mr. adams wrote to the astronomer-royal several additional communications, making improvements in his theory, and giving what he considered nearer and nearer approximations for the place of the planet. he also now answered quite satisfactorily, but too late, the question about the radius vector sent to him months before. let us return to leverrier. this great man was likewise engaged in improving his theory and in considering how best the optical search could be conducted. actuated, probably, by the knowledge that in such matters as cataloguing and mapping germany was then, as now, far ahead of all the other nations of the world, he wrote in september (the same september as sir john herschel delivered his eloquent address at southampton) to berlin. leverrier wrote, i say, to dr. galle, head of the observatory at berlin, saying to him, clearly and decidedly, that the new planet was now in or close to such and such a position, and that if he would point his telescope to that part of the heavens he would see it; and, moreover, that he would be able to tell it from a star by its having a sensible magnitude, or disk, instead of being a mere point. galle got the letter on the 23rd of september, 1846. that same evening he did point his telescope to the place leverrier told him, and he saw the planet that very night. he recognized it first by its appearance. to his practised eye it did seem to have a small disk, and not quite the same aspect as an ordinary star. he then consulted bremiker's great star chart, the part just engraved and finished, and sure enough on that chart there was no such star there. undoubtedly it was the planet. the news flashed over europe at the maximum speed with which news could travel at that date (which was not very fast); and by the 1st of october professor challis and mr. adams heard it at cambridge, and had the pleasure of knowing that they were forestalled, and that england was out of the race. it was an unconscious race to all concerned, however. those in france knew nothing of the search going on in england. mr. adams's papers had never been published; and very annoyed the french were when a claim was set up on his behalf to a share in this magnificent discovery. controversies and recriminations, excuses and justifications, followed; but the discussion has now settled down. all the world honours the bright genius and mathematical skill of mr. adams, and recognizes that he first solved the problem by calculation. all the world, too, perceives clearly the no less eminent mathematical talents of m. leverrier, but it recognizes in him something more than the mere mathematician--the man of energy, decision, and character. lecture xvi comets and meteors we have now considered the solar system in several aspects, and we have passed in review something of what is known about the stars. we have seen how each star is itself, in all probability, the centre of another and distinct solar system, the constituents of which are too dark and far off to be visible to us; nothing visible here but the central sun alone, and that only as a twinkling speck. but between our solar system and these other suns--between each of these suns and all the rest--there exist vast empty spaces, apparently devoid of matter. we have now to ask, are these spaces really empty? is there really nothing in space but the nebulæ, the suns, their planets, and their satellites? are all the bodies in space of this gigantic size? may there not be an infinitude of small bodies as well? the answer to this question is in the affirmative. there appears to be no special size suited to the vastness of space; we find, as a matter of fact, bodies of all manner of sizes, ranging by gradations from the most tremendous suns, like sirius, down through ordinary suns to smaller ones, then to planets of all sizes, satellites still smaller, then the asteroids, till we come to the smallest satellite of mars, only about ten miles in diameter, and weighing only some billion tons--the smallest of the regular bodies belonging to the solar system known. but, besides all these, there are found to occur other masses, not much bigger and some probably smaller, and these we call comets when we see them. below these, again, we find masses varying from a few tons in weight down to only a few pounds or ounces, and these when we see them, which is not often, we call meteors or shooting-stars; and to the size of these meteorites there would appear to be no limit: some may be literal grains of dust. there seems to be a regular gradation of size, therefore, ranging from sirius to dust; and apparently we must regard all space as full of these cosmic particles--stray fragments, as it were, perhaps of some older world, perhaps going to help to form a new one some day. as kepler said, there are more "comets" in the sky than fish in the sea. not that they are at all crowded together, else they would make a cosmic haze. the transparency of space shows that there must be an enormous proportion of clear space between each, and they are probably much more concentrated near one of the big bodies than they are in interstellar space.[30] even during the furious hail of meteors in november 1866 it was estimated that their average distance apart in the thickest of the shower was 35 miles. consider the nature of a meteor or shooting-star. we ordinarily see them as a mere streak of light; sometimes they leave a luminous tail behind them; occasionally they appear as an actual fire-ball, accompanied by an explosion; sometimes, but very seldom, they are seen to drop, and may subsequently be dug up as a lump of iron or rock, showing signs of rough treatment by excoriation and heat. these last are the meteorites, or siderites, or aërolites, or bolides, of our museums. they are popularly spoken of as thunderbolts, though they have nothing whatever to do with atmospheric electricity. [illustration: fig. 95.--meteorite.] they appear to be travelling rocky or metallic fragments which in their journey through space are caught in the earth's atmosphere and instantaneously ignited by the friction. far away in the depths of space one of these bodies felt the attracting power of the sun, and began moving towards him. as it approached, its speed grew gradually quicker and quicker continually, until by the time it has approached to within the distance of the earth, it whizzes past with the velocity of twenty-six miles a second. the earth is moving on its own account nineteen miles every second. if the two bodies happened to be moving in opposite directions, the combined speed would be terrific; and the faintest trace of atmosphere, miles above the earth's surface, would exert a furious grinding action on the stone. a stream of particles would be torn off; if of iron, they would burn like a shower of filings from a firework, thus forming a trail; and the mass itself would be dissipated, shattered to fragments in an instant. [illustration: fig. 96.--meteor stream crossing field of telescope.] [illustration: fig. 97.--diagram of direction of earth's orbital motion, showing that after midnight, _i.e._ between midnight and noon, more asteroids are likely to be swept up by any locality than between noon and midnight. [from sir r.s. ball.]] even if the earth were moving laterally, the same thing would occur. but if earth and stone happened to be moving in the same direction, there would be only the differential velocity of seven miles a second; and though this is in all conscience great enough, yet there might be a chance for a residue of the nucleus to escape entire destruction, though it would be scraped, heated, and superficially molten by the friction; but so much of its speed would be rubbed out of it, that on striking the earth it might bury itself only a few feet or yards in the soil, so that it could be dug out. the number of those which thus reach the earth is comparatively infinitesimal. nearly all get ground up and dissipated by the atmosphere; and fortunate it is for us that they are so. this bombardment of the exposed face of the moon must be something terrible.[31] thus, then, every shooting-star we see, and all the myriads that we do not and cannot see because they occur in the day-time, all these bright flashes or streaks, represent the death and burial of one of these flying stones. it had been careering on its own account through space for untold ages, till it meets a planet. it cannot strike the actual body of the planet--the atmosphere is a sufficient screen; the tremendous friction reduces it to dust in an instant, and this dust then quietly and leisurely settles down on to the surface. evidence of the settlement of meteoric dust is not easy to obtain in such a place as england, where the dust which accumulates is seldom of a celestial character; but on the snow-fields of greenland or the himalayas dust can be found; and by a committee of the british association distinct evidence of molten globules of iron and other materials appropriate to aërolites has been obtained, by the simple process of collecting, melting, and filtering long exposed snow. volcanic ash may be mingled with it, but under the microscope the volcanic and the meteoric constituents have each a distinctive character. the quantity of meteoric material which reaches the earth as dust must be immensely in excess of the minute quantity which arrives in the form of lumps. hundreds or thousands of tons per annum must be received; and the accretion must, one would think, in the course of ages be able to exert some influence on the period of the earth's rotation--the length of the day. it is too small, however, to have been yet certainly detected. possibly, it is altogether negligible. it has been suggested that those stones which actually fall are not the true cosmic wanderers, but are merely fragments of our own earth, cast up by powerful volcanoes long ago when the igneous power of the earth was more vigorous than now--cast up with a speed of close upon seven miles a second; and now in these quiet times gradually being swept up by the earth, and so returning whence they came. i confess i am unable to draw a clear distinction between one set and the other. some falling stars may have had an origin of this sort, but certainly others have not; and it would seem very unlikely that one set only should fall bodily upon the earth, while the others should always be rubbed to powder. still, it is a possibility to be borne in mind. we have spoken of these cosmic visitors as wandering masses of stone or iron; but we should be wrong if we associated with the term "wandering" any ideas of lawlessness and irregularity of path. these small lumps of matter are as obedient to the law of gravity as any large ones can be. they must all, therefore, have definite orbits, and these orbits will have reference to the main attracting power of our system--they will, in fact, be nearly all careering round the sun. each planet may, in truth, have a certain following of its own. within the limited sphere of the earth's predominant attraction, for instance, extending some way beyond the moon, we may have a number of satellites that we never see, all revolving regularly in elliptic orbits round the earth. but, comparatively speaking, these satellite meteorites are few. the great bulk of them will be of a planetary character--they will be attendant upon the sun. it may seem strange that such minute bodies should have regular orbits and obey kepler's laws, but they must. all three laws must be as rigorously obeyed by them as by the planets themselves. there is nothing in the smallness of a particle to excuse it from implicit obedience to law. the only consequence of their smallness is their inability to perturb others. they cannot appreciably perturb either the planets they approach or each other. the attracting power of a lump one million tons in weight is very minute. a pound, on the surface of such a body of the same density as the earth, would be only pulled to it with a force equal to that with which the earth pulls a grain. so the perturbing power of such a mass on distant bodies is imperceptible. it is a good thing it is so: accurate astronomy would be impossible if we had to take into account the perturbations caused by a crowd of invisible bodies. astronomy would then approach in complexity some of the problems of physics. but though we may be convinced from the facts of gravitation that these meteoric stones, and all other bodies flying through space near our solar system, must be constrained by the sun to obey kepler's laws, and fly round it in some regular elliptic or hyperbolic orbit, what chance have we of determining that orbit? at first sight, a very poor chance, for we never see them except for the instant when they splash into our atmosphere; and for them that instant is instant death. it is unlikely that any escape that ordeal, and even if they do, their career and orbit are effectually changed. henceforward they must become attendants on the earth. they may drop on to its surface, or they may duck out of our atmosphere again, and revolve round us unseen in the clear space between earth and moon. nevertheless, although the problem of determining the original orbit of any given set of shooting-stars before it struck us would seem nearly insoluble, it has been solved, and solved with some approach to accuracy; being done by the help of observations of certain other bodies. the bodies by whose help this difficult problem has been attacked and resolved are comets. what are comets? i must tell you that the scientific world is not entirely and completely decided on the structure of comets. there are many floating ideas on the subject, and some certain knowledge. but the subject is still, in many respects, an open one, and the ideas i propose to advocate you will accept for no more than they are worth, viz. as worthy to be compared with other and different views. up to the time of newton, the nature of comets was entirely unknown. they were regarded with superstitious awe as fiery portents, and were supposed to be connected with the death of some king, or with some national catastrophe. even so late as the first edition of the _principia_ the problem of comets was unsolved, and their theory is not given; but between the first and the second editions a large comet appeared, in 1680, and newton speculated on its appearance and behaviour. it rushed down very close to the sun, spun half round him very quickly, and then receded from him again. if it were a material substance, to which the law of gravitation applied, it must be moving in a conic section with the sun in one focus, and its radius vector must sweep out equal areas in equal times. examining the record of its positions made at observatories, he found its observed path quite accordant with theory; and the motion of comets was from that time understood. up to that time no one had attempted to calculate an orbit for a comet. they had been thought irregular and lawless bodies. now they were recognized as perfectly obedient to the law of gravitation, and revolving round the sun like everything else--as members, in fact, of our solar system, though not necessarily permanent members. but the orbit of a comet is very different from a planetary one. the excentricity of its orbit is enormous--in other words, it is either a very elongated ellipse or a parabola. the comet of 1680, newton found to move in an orbit so nearly a parabola that the time of describing it must be reckoned in hundreds of years at the least. it is now thought possible that it may not be quite a parabola, but an ellipse so elongated that it will not return till 2255. until that date arrives, however, uncertainty will prevail as to whether it is a periodic comet, or one of those that only visit our system once. if it be periodic, as suspected, it is the same as appeared when julius cæsar was killed, and which likewise appeared in the years 531 and 1106 a.d. should it appear in 2255, our posterity will probably regard it as a memorial of newton. [illustration: fig. 98.--parabolic and elliptic orbits. the _a b_ (visible) portions are indistinguishable.] the next comet discussed in the light of the theory of gravitation was the famous one of halley. you know something of the history of this. its period is 75-1/2 years. halley saw it in 1682, and predicted its return in 1758 or 1759--the first cometary prediction. clairaut calculated its return right within a month (p. 219). it has been back once more, in 1835; and this time its date was correctly predicted within three days, because uranus was now known. it was away at its furthest point in 1873. it will be back again in 1911. [illustration: fig. 99.--orbit of halley's comet.] coming to recent times, we have the great comets of 1843 and of 1858, the history of neither being known. quite possibly they arrived then for the first time. possibly the second will appear again in 3808. but besides these great comets, there are a multitude of telescopic ones, which do not show these striking features, and have no gigantic tail. some have no tail at all, others have at best a few insignificant streamers, and others show a faint haze looking like a microscopic nebula. all these comets are of considerable extent--some millions of miles thick usually, and yet stars are clearly visible through them. hence they must be matter of very small density; their tails can be nothing more dense than a filmy mist, but their nucleus must be something more solid and substantial. [illustration: fig. 100.--various appearances of halley's comet when last seen.] i have said that comets arrive from the depths of space, rush towards and round the sun, whizzing past the earth with a speed of twenty-six miles a second, on round the sun with a far greater velocity than that, and then rush off again. now, all the time they are away from the sun they are invisible. it is only as they get near him that they begin to expand and throw off tails and other appendages. the sun's heat is evidently evaporating them, and driving away a cloud of mist and volatile matter. this is when they can be seen. the comet is most gorgeous when it is near the sun, and as soon as it gets a reasonable distance away from him it is perfectly invisible. the matter evaporated from the comet by the sun's heat does not return--it is lost to the comet; and hence, after a few such journeys, its volatile matter gets appreciably diminished, and so old-established periodic comets have no tails to speak of. but the new visitants, coming from the depths of space for the first time--these have great supplies of volatile matter, and these are they which show the most magnificent tails. [illustration: fig. 101.--head of donati's comet of 1858.] the tail of a comet is always directed away from the sun as if it were repelled. to this rule there is no exception. it is suggested, and held as most probable, that the tail and sun are similarly electrified, and that the repulsion of the tail is electrical repulsion. some great force is obviously at work to account for the enormous distance to which the tail is shot in a few hours. the pressure of the sun's light can do something, and is a force that must not be ignored when small particles are being dealt with. (cf. _modern views of electricity_, 2nd edition, p. 363.) now just think what analogies there are between comets and meteors. both are bodies travelling in orbits round the sun, and both are mostly invisible, but both become visible to us under certain circumstances. meteors become visible when they plunge into the extreme limits of our atmosphere. comets become visible when they approach the sun. is it possible that comets are large meteors which dip into the solar atmosphere, and are thus rendered conspicuously luminous? certainly they do not dip into the actual main atmosphere of the sun, else they would be utterly destroyed; but it is possible that the sun has a faint trace of atmosphere extending far beyond this, and into this perhaps these meteors dip, and glow with the friction. the particles thrown off might be, also by friction, electrified; and the vaporous tail might be thus accounted for. [illustration: fig. 102.--halley's comet.] let us make this hypothesis provisionally--that comets are large meteors, or a compact swarm of meteors, which, coming near the sun, find a highly rarefied sort of atmosphere, in which they get heated and partly vaporized, just as ordinary meteorites do when they dip into the atmosphere of the earth. and let us see whether any facts bear out the analogy and justify the hypothesis. i must tell you now the history of three bodies, and you will see that some intimate connection between comets and meteors is proved. the three bodies are known as, first, encke's comet; second, biela's comet; third, the november swarm of meteors. encke's comet (one of those discovered by miss herschel) is an insignificant-looking telescopic comet of small period, the orbit of which was well known, and which was carefully observed at each reappearance after encke had calculated its orbit. it was the quickest of the comets, returning every 3-1/2 years. [illustration: fig. 103.--encke's comet.] it was found, however, that its period was not quite constant; it kept on getting slightly shorter. the comet, in fact, returned to the sun slightly before its time. now this effect is exactly what friction against a solar atmosphere would bring about. every time it passed near the sun a little velocity would be rubbed out of it. but the velocity is that which carries it away, hence it would not go quite so far, and therefore would return a little sooner. any revolving body subject to friction must revolve quicker and quicker, and get nearer and nearer its central body, until, if the process goes on long enough, it must drop upon its surface. this seems the kind of thing happening to encke's comet. the effect is very small, and not thoroughly proved; but, so far as it goes, the evidence points to a greatly extended rare solar atmosphere, which rubs some energy out of it at every perihelion passage. [illustration: fig. 104.--biela's comet as last seen, in two portions.] next, biela's comet. this also was a well known and carefully observed telescopic comet, with a period of six years. in one of its distant excursions, it was calculated that it must pass very near jupiter, and much curiosity was excited as to what would happen to it in consequence of the perturbation it must experience. as i have said, comets are only visible as they approach the sun, and a watch was kept for it about its appointed time. it was late, but it did ultimately arrive. the singular thing about it, however, was that it was now double. it had apparently separated into two. this was in 1846. it was looked for again in 1852, and this time the components were further separated. sometimes one was brighter, sometimes the other. next time it ought to have come round no one could find either portion. the comet seemed to have wholly disappeared. it has never been seen since. it was then recorded and advertised as the missing comet. but now comes the interesting part of the story. the orbit of this biela comet was well known, and it was found that on a certain night in 1872 the earth would cross the orbit, and had some chance of encountering the comet. not a very likely chance, because it need not be in that part of its orbit at the time; but it was suspected not to be far off--if still existent. well, the night arrived, the earth did cross the orbit, and there was seen, not the comet, but a number of shooting-stars. not one body, nor yet two, but a multitude of bodies--in fact, a swarm of meteors. not a very great swarm, such as sometimes occurs, but still a quite noticeable one; and this shower of meteors is definitely recognized as flying along the track of biela's comet. they are known as the andromedes. this observation has been generalized. every cometary orbit is marked by a ring of meteoric stones travelling round it, and whenever a number of shooting-stars are seen quickly one after the other, it is an evidence that we are crossing the track of some comet. but suppose instead of only crossing the track of a comet we were to pass close to the comet itself, we should then expect to see an extraordinary swarm--a multitude of shooting-stars. such phenomena have occurred. the most famous are those known as the november meteors, or leonids. this is the third of those bodies whose history i had to tell you. professor h.a. newton, of america, by examining ancient records arrived at the conclusion that the earth passed through a certain definite meteor shoal every thirty-three years. he found, in fact, that every thirty-three years an unusual flight of shooting-stars was witnessed in november, the earliest record being 599 a.d. their last appearance had been in 1833, and he therefore predicted their return in 1866 or 1867. sure enough, in november, 1866, they appeared; and many must remember seeing that glorious display. although their hail was almost continuous, it is estimated that their average distance apart was thirty-five miles! their radiant point was and always is in the constellation leo, and hence their name leonids. [illustration: fig. 105.--radiant point perspective. the arrows represent a number of approximately parallel meteor-streaks foreshortened from a common vanishing-point.] a parallel stream fixed in space necessarily exhibits a definite aspect with reference to the fixed stars. its aspect with respect to the earth will be very changeable, because of the rotation and revolution of that body, but its position with respect to constellations will be steady. hence each meteor swarm, being a steady parallel stream of rushing masses, always strikes us from the same point in stellar space, and by this point (or radiant) it is identified and named. the paths do not appear to us to be parallel, because of perspective: they seem to radiate and spread in all directions from a fixed centre like spokes, but all these diverging streaks are really parallel lines optically foreshortened by different amounts so as to produce the radiant impression. the annexed diagram (fig. 105) clearly illustrates the fact that the "radiant" is the vanishing point of a number of parallel lines. [illustration: fig. 106.--orbit of november meteors.] this swarm is specially interesting to us from the fact that we cross its orbit every year. its orbit and the earth's intersect. every november we go through it, and hence every november we see a few stragglers of this immense swarm. the swarm itself takes thirty-three years on its revolution round the sun, and hence we only encounter it every thirty-three years. the swarm is of immense size. in breadth it is such that the earth, flying nineteen miles a second, takes four or five hours to cross it, and this is therefore the time the display lasts. but in length it is far more enormous. the speed with which it travels is twenty-five miles a second, (for its orbit extends as far as uranus, although by no means parabolic), and yet it takes more than a year to pass. imagine a procession 200,000 miles broad, every individual rushing along at the rate of twenty-five miles every second, and the whole procession so long that it takes more than a year to pass. it is like a gigantic shoal of herrings swimming round and round the sun every thirty-three years, and travelling past the earth with that tremendous velocity of twenty-five miles a second. the earth dashes through the swarm and sweeps up myriads. think of the countless numbers swept up by the whole earth in crossing such a shoal as that! but heaps more remain, and probably the millions which are destroyed every thirty-three years have not yet made any very important difference to the numbers still remaining. the earth never misses this swarm. every thirty-three years it is bound to pass through some part of them, for the shoal is so long that if the head is just missed one november the tail will be encountered next november. this is a plain and obvious result of its enormous length. it may be likened to a two-foot length of sewing silk swimming round and round an oval sixty feet in circumference. but, you will say, although the numbers are so great that destroying a few millions or so every thirty-three years makes but little difference to them, yet, if this process has been going on from all eternity, they ought to be all swept up. granted; and no doubt the most ancient swarms have already all or nearly all been swept up. [illustration: fig. 107.--orbit of november meteors; showing their probable parabolic orbit previous to 126 a.d., and its sudden conversion into an elliptic orbit by the violent perturbation caused by uranus, which at that date occupied the position shown.] the august meteors, or perseids, are an example. every august we cross their path, and we have a small meteoric display radiating from the sword-hand of perseus, but never specially more in one august than another. it would seem as if the main shoal has disappeared, and nothing is now left but the stragglers; or perhaps it is that the shoal has gradually become uniformly distributed all along the path. anyhow, these august meteors are reckoned much more ancient members of the solar system than are the november meteors. the november meteors are believed to have entered the solar system in the year 126 a.d. this may seem an extraordinary statement. it is not final, but it is based on the calculations of leverrier--confirmed recently by mr. adams. a few moments will suffice to make the grounds of it clear. leverrier calculated the orbit of the november meteors, and found them to be an oval extending beyond uranus. it was perturbed by the outer planets near which it went, so that in past times it must have moved in a slightly different orbit. calculating back to their past positions, it was found that in a certain year it must have gone very near to uranus, and that by the perturbation of this planet its path had been completely changed. originally it had in all probability been a comet, flying in a parabolic orbit towards the sun like many others. this one, encountering uranus, was pulled to pieces as it were, and its orbit made elliptical as shown in fig. 107. it was no longer free to escape and go away into the depths of space: it was enchained and made a member of the solar system. it also ceased to be a comet; it was degraded into a shoal of meteors. this is believed to be the past history of this splendid swarm. since its introduction to the solar system it has made 52 revolutions: its next return is due in november, 1899, and i hope that it may occur in the english dusk, and (see fig. 97) in a cloudless after-midnight sky, as it did in 1866. notes for lecture xvii the tide-generating force of one body on another is directly as the mass of the one body and inversely as the cube of the distance between them. hence the moon is more effective in producing terrestrial tides than the sun. the tidal wave directly produced by the moon in the open ocean is about 5 feet high, that produced by the sun is about 2 feet. hence the average spring tide is to the average neap as about 7 to 3. the lunar tide varies between apogee and perigee from 4·3 to 5·9. the solar tide varies between aphelion and perihelion from 1·9 to 2·1. hence the highest spring tide is to the lowest neap as 5·9 + 2·1 is to 4·3 -2·1, or as 8 to 2·2. the semi-synchronous oscillation of the southern ocean raises the magnitude of oceanic tides somewhat above these directly generated values. oceanic tides are true waves, not currents. coast tides are currents. the momentum of the water, when the tidal wave breaks upon a continent and rushes up channels, raises coast tides to a much greater height--in some places up to 50 or 60 feet, or even more. early observed connections between moon and tides would be these:- 1st. spring tides at new and full moon. 2nd. average interval between tide and tide is half a lunar, not a solar, day--a lunar day being the interval between two successive returns of the moon to the meridian: 24 hours and 50 minutes. 3rd. the tides of a given place at new and full moon occur always at the same time of day whatever the season of the year. lecture xvii the tides persons accustomed to make use of the mersey landing-stages can hardly fail to have been struck with two obvious phenomena. one is that the gangways thereto are sometimes almost level, and at other times very steep; another is that the water often rushes past the stage rather violently, sometimes south towards garston, sometimes north towards the sea. they observe, in fact, that the water has two periodic motions--one up and down, the other to and fro--a vertical and a horizontal motion. they may further observe, if they take the trouble, that a complete swing of the water, up and down, or to and fro, takes place about every twelve and a half hours; moreover, that soon after high and low water there is no current--the water is stationary, whereas about half-way between high and low it is rushing with maximum speed either up or down the river. to both these motions of the water the name _tide_ is given, and both are extremely important. sailors usually pay most attention to the horizontal motion, and on charts you find the tide-races marked; and the places where there is but a small horizontal rush of the water are labelled "very little tide here." landsmen, or, at any rate, such of the more philosophic sort as pay any attention to the matter at all, think most of the vertical motion of the water--its amount of rise and fall. dwellers in some low-lying districts in london are compelled to pay attention to the extra high tides of the thames, because it is, or was, very liable to overflow its banks and inundate their basements. sailors, however, on nearing a port are also greatly affected by the time and amount of high water there, especially when they are in a big ship; and we know well enough how frequently atlantic liners, after having accomplished their voyage with good speed, have to hang around for hours waiting till there is enough water to lift them over the bar--that standing obstruction, one feels inclined to say disgrace, to the liverpool harbour. [illustration: fig. 108.--the mersey] to us in liverpool the tides are of supreme importance--upon them the very existence of the city depends--for without them liverpool would not be a port. it may be familiar to many of you how this is, and yet it is a matter that cannot be passed over in silence. i will therefore call your attention to the ordnance survey of the estuaries of the mersey and the dee. you see first that there is a great tendency for sand-banks to accumulate all about this coast, from north wales right away round to southport. you see next that the port of chester has been practically silted up by the deposits of sand in the wide-mouthed dee, while the port of liverpool remains open owing to the scouring action of the tide in its peculiarly shaped channel. without the tides the mersey would be a wretched dribble not much bigger than it is at warrington. with them, this splendid basin is kept open, and a channel is cut of such depth that the _great eastern_ easily rode in it in all states of the water. the basin is filled with water every twelve hours through its narrow neck. the amount of water stored up in this basin at high tide i estimate as 600 million tons. all this quantity flows through the neck in six hours, and flows out again in the next six, scouring and cleansing and carrying mud and sand far out to sea. just at present the currents set strongest on the birkenhead side of the river, and accordingly a "pluckington bank" unfortunately grows under the liverpool stage. should this tendency to silt up the gates of our docks increase, land can be reclaimed on the other side of the river between tranmere and rock ferry, and an embankment made so as to deflect the water over liverpool way, and give us a fairer proportion of the current. after passing new brighton the water spreads out again to the left; its velocity forward diminishes; and after a few miles it has no power to cut away that sandbank known as the bar. should it be thought desirable to make it accomplish this, and sweep the bar further out to sea into deeper water, it is probable that a rude training wall (say of old hulks, or other removable partial obstruction) on the west of queen's channel, arranged so as to check the spreading out over all this useless area, may be quite sufficient to retain the needed extra impetus in the water, perhaps even without choking up the useful old rock channel, through which smaller ships still find convenient exit. now, although the horizontal rush of the tide is necessary to our existence as a port, it does not follow that the accompanying rise and fall of the water is an unmixed blessing. to it is due the need for all the expensive arrangements of docks and gates wherewith to store up the high-level water. quebec and new york are cities on such magnificent rivers that the current required to keep open channel is supplied without any tidal action, although quebec is nearly 1,000 miles from the open ocean; and accordingly, atlantic liners do not hover in mid-river and discharge passengers by tender, but they proceed straight to the side of the quays lining the river, or, as at new york, they dive into one of the pockets belonging to the company running the ship, and there discharge passengers and cargo without further trouble, and with no need for docks or gates. however, rivers like the st. lawrence and the hudson are the natural property of a gigantic continent; and we in england may be well contented with the possession of such tidal estuaries as the mersey, the thames, and the humber. that by pertinacious dredging the citizens of glasgow manage to get large ships right up their small river, the clyde, to the quays of the town, is a remarkable fact, and redounds very highly to their credit. we will now proceed to consider the connection existing between the horizontal rush of water and its vertical elevation, and ask, which is cause and which is effect? does the elevation of the ocean cause the tidal flow, or does the tidal flow cause the elevation? the answer is twofold: both statements are in some sense true. the prime cause of the tide is undoubtedly a vertical elevation of the ocean, a tidal wave or hump produced by the attraction of the moon. this hump as it passes the various channels opening into the ocean raises their level, and causes water to flow up them. but this simple oceanic tide, although the cause of all tide, is itself but a small affair. it seldom rises above six or seven feet, and tides on islands in mid-ocean have about this value or less. but the tides on our coasts are far greater than this--they rise twenty or thirty feet, or even fifty feet occasionally, at some places, as at bristol. why is this? the horizontal motion of the water gives it such an impetus or momentum that its motion far transcends that of the original impulse given to it, just as a push given to a pendulum may cause it to swing over a much greater arc than that through which the force acts. the inrushing water flowing up the english channel or the bristol channel or st. george's channel has such an impetus that it propels itself some twenty or thirty feet high before it has exhausted its momentum and begins to descend. in the bristol channel the gradual narrowing of the opening so much assists this action that the tides often rise forty feet, occasionally fifty feet, and rush still further up the severn in a precipitous and extraordinary hill of water called "the bore." some places are subject to considerable rise and fall of water with very little horizontal flow; others possess strong tidal races, but very little elevation and depression. the effect observed at any given place entirely depends on whether the place has the general character of a terminus, or whether it lies _en route_ to some great basin. you must understand, then, that all tide takes its rise in the free and open ocean under the action of the moon. no ordinary-sized sea like the north sea, or even the mediterranean, is big enough for more than a just appreciable tide to be generated in it. the pacific, the atlantic, and the southern oceans are the great tidal reservoirs, and in them the tides of the earth are generated as low flat humps of gigantic area, though only a few feet high, oscillating up and down in the period of approximately twelve hours. the tides we, and other coast-possessing nations, experience are the overflow or back-wash of these oceanic humps, and i will now show you in what manner the great atlantic tide-wave reaches the british isles twice a day. [illustration: fig. 109.--co-tidal lines.] fig. 109 shows the contour lines of the great wave as it rolls in east from the atlantic, getting split by the land's end and by ireland into three portions; one of which rushes up the english channel and through the straits of dover. another rolls up the irish sea, with a minor offshoot up the bristol channel, and, curling round anglesey, flows along the north wales coast and fills liverpool bay and the mersey. the third branch streams round the north coast of ireland, past the mull of cantyre and rathlin island; part fills up the firth of clyde, while the rest flows south, and, swirling round the west side of the isle of man, helps the southern current to fill the bay of liverpool. the rest of the great wave impinges on the coast of scotland, and, curling round it, fills up the north sea right away to the norway coast, and then flows down below denmark, joining the southern and earlier arriving stream. the diagram i show you is a rough chart of cotidal lines, which i made out of the information contained in _whitaker's almanac_. a place may thus be fed with tide by two distinct channels, and many curious phenomena occur in certain places from this cause. thus it may happen that one channel is six hours longer than the other, in which case a flow will arrive by one at the same time as an ebb arrives by the other; and the result will be that the place will have hardly any tide at all, one tide interfering with and neutralizing the other. this is more markedly observed at other parts of the world than in the british isles. whenever a place is reached by two channels of different length, its tides are sure to be peculiar, and probably small. another cause of small tide is the way the wave surges to and fro in a channel. the tidal wave surging up the english channel, for instance, gets largely reflected by the constriction at dover, and so a crest surges back again, as we may see waves reflected in a long trough or tilted bath. the result is that southampton has two high tides rapidly succeeding one another, and for three hours the high-water level varies but slightly--a fact of evident convenience to the port. places on a nodal line, so to speak, about the middle of the length of the channel, have a minimum of rise and fall, though the water rushes past them first violently up towards dover, where the rise is considerable, and then back again towards the ocean. at portland, for instance, the total rise and fall is very small: it is practically on a node. yarmouth, again, is near a less marked node in the north sea, where stationary waves likewise surge to and fro, and accordingly the tidal rise and fall at yarmouth is only about five feet (varying from four and a half to six), whereas at london it is twenty or thirty feet, and at flamborough head or leith it is from twelve to sixteen feet. it is generally supposed that water never flows up-hill, but in these cases of oscillation it flows up-hill for three hours together. the water is rushing up the english channel towards dover long after it is highest at the dover end; it goes on piling itself up, until its momentum is checked by the pressure, and then it surges back. it behaves, in fact, very like the bob of a pendulum, which rises against gravity at every quarter swing. to get a very large tide, the place ought to be directly accessible by a long sweep of a channel to the open ocean, and if it is situate on a gradually converging opening, the ebb and flow may be enormous. the severn is the best example of this on the british isles; but the largest tides in the world are found, i believe, in the bay of fundy, on the coast of north america, where they sometimes rise one hundred and twenty feet. excessive or extra tides may be produced occasionally in any place by the propelling force of a high wind driving the water towards the shore; also by a low barometer, _i.e._ by a local decrease in the pressure of the air. well, now, leaving these topographical details concerning tides, which we see to be due to great oceanic humps (great in area that is, though small in height), let us proceed to ask what causes these humps; and if it be the moon that does it, how does it do it? the statement that the moon causes the tides sounds at first rather an absurdity, and a mere popular superstition. galileo chaffed kepler for believing it. who it was that discovered the connection between moon and tides we know not--probably it is a thing which has been several times rediscovered by observant sailors or coast-dwellers--and it is certainly a very ancient piece of information. probably the first connection observed was that about full moon and about new moon the tides are extra high, being called spring tides, whereas about half-moon the tides are much less, and are called neap tides. the word spring in this connection has no reference to the season of the year; except that both words probably represent the same idea of energetic uprising or upspringing, while the word neap comes from nip, and means pinched, scanty, nipped tide. the next connection likely to be observed would be that the interval between two day tides was not exactly a solar day of twenty-four hours, but a lunar day of fifty minutes longer. for by reason of the moon's monthly motion it lags behind the sun about fifty minutes a day, and the tides do the same, and so perpetually occur later and later, about fifty minutes a day later, or 12 hours and 25 minutes on the average between tide and tide. a third and still more striking connection was also discovered by some of the ancient great navigators and philosophers--viz. that the time of high water at a given place at full moon is always the same, or very nearly so. in other words, the highest or spring tides always occur nearly at the same time of day at a given place. for instance, at liverpool this time is noon and midnight. london is about two hours and a half later. each port has its own time for receiving a given tide, and the time is called the "establishment" of the port. look out a day when the moon is full, and you will find the liverpool high tide occurs at half-past eleven, or close upon it. the same happens when the moon is new. a day after full or new moon the spring tides rise to their highest, and these extra high tides always occur in liverpool at noon and at midnight, whatever the season of the year. about the equinoxes they are liable to be extraordinarily high. the extra low tides here are therefore at 6 a.m. and 6 p.m., and the 6 p.m. low tide is a nuisance to the river steamers. the spring tides at london are highest about half-past two. * * * * * it is, therefore, quite clear that the moon has to do with the tides. it and the sun together are, in fact, the whole cause of them; and the mode in which these bodies act by gravitative attraction was first made out and explained in remarkably full detail by sir isaac newton. you will find his account of the tides in the second and third books of the _principia_; and though the theory does not occupy more than a few pages of that immortal work, he succeeds not only in explaining the local tidal peculiarities, much as i have done to-night, but also in calculating the approximate height of mid-ocean solar tide; and from the observed lunar tide he shows how to determine the then quite unknown mass of the moon. this was a quite extraordinary achievement, the difficulty of which it is not easy for a person unused to similar discussions fully to appreciate. it is, indeed, but a small part of what newton accomplished, but by itself it is sufficient to confer immortality upon any ordinary philosopher, and to place him in a front rank. [illustration: fig. 110.--whirling earth model.] to make intelligible newton's theory of the tides, i must not attempt to go into too great detail. i will consider only the salient points. first, you know that every mass of matter attracts every other piece of matter; second, that the moon revolves round the earth, or rather that the earth and moon revolve round their common centre of gravity once a month; third, that the earth spins on its own axis once a day; fourth, that when a thing is whirled round, it tends to fly out from the centre and requires a force to hold it in. these are the principles involved. you can whirl a bucket full of water vertically round without spilling it. make an elastic globe rotate, and it bulges out into an oblate or orange shape; as illustrated by the model shown in fig. 110. this is exactly what the earth does, and newton calculated the bulging of it as fourteen miles all round the equator. make an elastic globe revolve round a fixed centre outside itself, and it gets pulled into a prolate or lemon shape; the simplest illustrative experiment is to attach a string to an elastic bag or football full of water, and whirl it round and round. its prolateness is readily visible. now consider the earth and moon revolving round each other like a man whirling a child round. the child travels furthest, but the man cannot merely rotate, he leans back and thus also describes a small circle: so does the earth; it revolves round the common centre of gravity of earth and moon (_cf._ p. 212). this is a vital point in the comprehension of the tides: the earth's centre is not at rest, but is being whirled round by the moon, in a circle about 1/80 as big as the circle which the moon describes, because the earth weighs eighty times as much as the moon. the effect of the revolution is to make both bodies slightly protrude in the direction of the line joining them; they become slightly "prolate" as it is called--that is, lemon-shaped. illustrating still by the man and child, the child's legs fly outwards so that he is elongated in the direction of a radius; the man's coat-tails fly out too, so that he too is similarly though less elongated. these elongations or protuberances constitute the tides. [illustration: fig. 111.--earth and moon model, illustrating the production of statical or "equilibrium" tides when the whole is whirled about the point g.] fig. 111 shows a model to illustrate the mechanism. a couple of cardboard disks (to represent globes of course), one four times the diameter of the other, and each loaded so as to have about the correct earth-moon ratio of weights, are fixed at either end of a long stick, and they balance about a certain point, which is their common centre of gravity. for convenience this point is taken a trifle too far out from the centre of the earth--that is, just beyond its surface. through the balancing point g a bradawl is stuck, and on that as pivot the whole readily revolves. now, behind the circular disks, you see, are four pieces of card of appropriate shape, which are able to slide out under proper forces. they are shown dotted in the figure, and are lettered a, b, c, d. the inner pair, b and c, are attached to each other by a bit of string, which has to typify the attraction of gravitation; the outer pair, a and d, are not attached to anything, but have a certain amount of play against friction in slots parallel to the length of the stick. the moon-disk is also slotted, so a small amount of motion is possible to it along the stick or bar. these things being so arranged, and the protuberant pieces of card being all pushed home, so that they are hidden behind their respective disks, the whole is spun rapidly round the centre of gravity, g. the result of a brief spin is to make a and d fly out by centrifugal force and show, as in the figure; while the moon, flying out too in its slot, tightens up the string, which causes b and c to be pulled out too. thus all four high tides are produced, two on the earth and two on the moon, a and d being caused by centrifugal force, b and c by the attraction of gravitation. each disk has become prolate in the same sort of fashion as yielding globes do. of course the fluid ocean takes this shape more easily and more completely than the solid earth can, and so here are the very oceanic humps we have been talking about, and about three feet high (fig. 112). if there were a sea on the _moon_, its humps would be a good deal bigger; but there probably is no sea there, and if there were, the earth's tides are more interesting to us, at any rate to begin with. [illustration: fig. 112.--earth and moon (earth's rotation neglected).] the humps as so far treated are always protruding in the earth-moon line, and are stationary. but now we have to remember that the earth is spinning inside them. it is not easy to see what precise effect this spin will have upon the humps, even if the world were covered with a uniform ocean; but we can see at any rate that however much they may get displaced, and they do get displaced a good deal, they cannot possibly be carried round and round. the whole explanation we have given of their causes shows that they must maintain some steady aspect with respect to the moon--in other words, they must remain stationary as the earth spins round. not that the same identical water remains stationary, for in that case it would have to be dragged over the earth's equator at the rate of 1,000 miles an hour, but the hump or wave-crest remains stationary. it is a true wave, or form only, and consists of continuously changing individual particles. the same is true of all waves, except breaking ones. given, then, these stationary humps and the earth spinning on its axis, we see that a given place on the earth will be carried round and round, now past a hump, and six hours later past a depression: another six hours and it will be at the antipodal hump, and so on. thus every six hours we shall travel from the region in space where the water is high to the region where it is low; and ignoring our own motion we shall say that the sea first rises and then falls; and so, with respect to the place, it does. thus the succession of high and low water, and the two high tides every twenty-four hours, are easily understood in their easiest and most elementary aspect. a more complete account of the matter it will be wisest not to attempt: suffice it to say that the difficulties soon become formidable when the inertia of the water, its natural time of oscillation, the varying obliquity of the moon to the ecliptic, its varying distance, and the disturbing action of the sun are taken into consideration. when all these things are included, the problem becomes to ordinary minds overwhelming. a great many of these difficulties were successfully attacked by laplace. others remained for modern philosophers, among whom are sir george airy, sir william thomson, and professor george darwin. i may just mention that the main and simplest effect of including the inertia or momentum of the water is to dislocate the obvious and simple connexion between high water and high moon; inertia always tends to make an effect differ in phase by a quarter period from the cause producing it, as may be illustrated by a swinging pendulum. hence high water is not to be expected when the tide-raising force is a maximum, but six hours later; so that, considering inertia and neglecting friction, there would be low water under the moon. including friction, something nearer the equilibrium state of things occurs. with _sufficient_ friction the motion becomes dead-beat again, _i.e._ follows closely the force that causes it. returning to the elementary discussion, we see that the rotation of the earth with respect to the humps will not be performed in exactly twenty-four hours, because the humps are travelling slowly after the moon, and will complete a revolution in a month in the same direction as the earth is rotating. hence a place on the earth has to catch them up, and so each high tide arrives later and later each day--roughly speaking, an hour later for each day tide; not by any means a constant interval, because of superposed disturbances not here mentioned, but on the average about fifty minutes. we see, then, that as a result of all this we get a pair of humps travelling all over the surface of the earth, about once a day. if the earth were all ocean (and in the southern hemisphere it is nearly all ocean), then they would go travelling across the earth, tidal waves three feet high, and constituting the mid-ocean tides. but in the northern hemisphere they can only thus journey a little way without striking land. as the moon rises at a place on the east shores of the atlantic, for instance, the waters begin to flow in towards this place, or the tide begins to rise. this goes on till the moon is overhead and for some time afterwards, when the tide is at its highest. the hump then follows the moon in its apparent journey across to america, and there precipitates itself upon the coast, rushing up all the channels, and constituting the land tide. at the same time, the water is dragged away from the east shores, and so _our_ tide is at its lowest. the same thing repeats itself in a little more than twelve hours again, when the other hump passes over the atlantic, as the moon journeys beneath the earth, and so on every day. in the free southern ocean, where land obstruction is comparatively absent, the water gets up a considerable swing by reason of its accumulated momentum, and this modifies and increases the open ocean tides there. also for some reason, i suppose because of the natural time of swing of the water, one of the humps is there usually much larger than the other; and so places in the indian and other offshoots of the southern ocean get their really high tide only once every twenty-four hours. these southern tides are in fact much more complicated than those the british isles receive. ours are singularly simple. no doubt some trace of the influence of the southern ocean is felt in the north atlantic, but any ocean extending over 90° of longitude is big enough to have its own tides generated; and i imagine that the main tides we feel are thus produced on the spot, and that they are simple because the damping-out being vigorous, and accumulated effects small, we feel the tide-producing forces more directly. but for authoritative statements on tides, other books must be read. i have thought, and still think, it best in an elementary exposition to begin by a consideration of the tide-generating forces as if they acted on a non-rotating earth. it is the tide generating forces, and not the tides themselves, that are really represented in figs. 112 and 114. the rotation of the earth then comes in as a disturbing cause. a more complete exposition would begin with the rotating earth, and would superpose the attraction of the moon as a disturbing cause, treating it as a problem in planetary perturbation, the ocean being a sort of satellite of the earth. this treatment, introducing inertia but ignoring friction and land obstruction, gives low water in the line of pull, and high water at right angles, or where the pull is zero; in the same sort of way as a pendulum bob is highest where most force is pulling it down, and lowest where no force is acting on it. for a clear treatment of the tides as due to the perturbing forces of sun and moon, see a little book by mr. t.k. abbott of trinity college, dublin. (longman.) [illustration: fig. 113.--maps showing how comparatively free from land obstruction the ocean in the southern hemisphere is.] if the moon were the only body that swung the earth round, this is all that need be said in an elementary treatment; but it is not the only one. the moon swings the earth round once a month, the sun swings it round once a year. the circle of swing is bigger, but the speed is so much slower that the protuberance produced is only one-third of that caused by the monthly whirl; _i.e._ the simple solar tide in the open sea, without taking momentum into account, is but a little more than a foot high, while the simple lunar tide is about three feet. when the two agree, we get a spring tide of four feet; when they oppose each other, we get a neap tide of only two feet. they assist each other at full moon and at new moon. at half-moon they oppose each other. so we have spring tides regularly once a fortnight, with neap tides in between. [illustration: fig. 114.--spring and neap tides.] fig. 114 gives the customary diagrams to illustrate these simple things. you see that when the moon and sun act at right angles (_i.e._ at every half-moon), the high tides of one coincide with the low tides of the other; and so, as a place is carried round by the earth's rotation, it always finds either solar or else lunar high water, and only experiences the difference of their two effects. whereas, when the sun and moon act in the same line (as they do at new and full moon), their high and low tides coincide, and a place feels their effects added together. the tide then rises extra high and falls extra low. [illustration: fig. 115.--tidal clock. the position of the disk b shows the height of the tide. the tide represented is a nearly high tide eight feet above mean level.] utilizing these principles, a very elementary form of tidal-clock, or tide-predicter, can be made, and for an open coast station it really would not give the tides so very badly. it consists of a sort of clock face with two hands, one nearly three times as long as the other. the short hand, ca, should revolve round c once in twelve hours, and the vertical height of its end a represents the height of the solar tide on the scale of horizontal lines ruled across the face of the clock. the long hand, ab, should revolve round a once in twelve hours and twenty-five minutes, and the height of its end b (if a were fixed on the zero line) would represent the lunar tide. the two revolutions are made to occur together, either by means of a link-work parallelogram, or, what is better in practice, by a string and pulleys, as shown; and the height of the end point, b, of the third side or resultant, cb, read off on a scale of horizontal parallel lines behind, represents the combination or actual tide at the place. every fortnight the two will agree, and you will get spring tides of maximum height ca + ab; every other fortnight the two will oppose, and you will get neap tides of maximum height ca-ab. such a clock, if set properly and driven in the ordinary way, would then roughly indicate the state of the tide whenever you chose to look at it and read the height of its indicating point. it would not indeed be very accurate, especially for such an inclosed station as liverpool is, and that is probably why they are not made. a great number of disturbances, some astronomical, some terrestrial, have to be taken into account in the complete theory. it is not an easy matter to do this, but it can be, and has been, done; and a tide-predicter has not only been constructed, but two of them are in regular work, predicting the tides for years hence--one, the property of the indian government, for coast stations of india; the other for various british and foreign stations, wherever the necessary preliminary observations have been made. these machines are the invention of sir william thomson. the tide-tables for indian ports are now always made by means of them. [illustration: fig. 116.--sir william thomson (lord kelvin).] [illustration: fig. 117.--tide-gauge for recording local tides, a pencil moved up and down by a float writes on a drum driven by clockwork.] the first thing to be done by any port which wishes its tides to be predicted is to set up a tide-gauge, or automatic recorder, and keep it working for a year or two. the tide-gauge is easy enough to understand: it marks the height of the tide at every instant by an irregular curved line like a barometer chart (fig. 117). these observational curves so obtained have next to be fed into a fearfully complex machine, which it would take a whole lecture to make even partially intelligible, but fig. 118 shows its aspect. it consists of ten integrating machines in a row, coupled up and working together. this is the "harmonic analyzer," and the result of passing the curve through this machine is to give you all the constituents of which it is built up, viz. the lunar tide, the solar tide, and eight of the sub-tides or disturbances. these ten values are then set off into a third machine, the tide-predicter proper. the general mode of action of this machine is not difficult to understand. it consists of a string wound over and under a set of pulleys, which are each set on an excentric, so as to have an up-and-down motion. these up-and-down motions are all different, and there are ten of these movable pulleys, which by their respective excursions represent the lunar tide, the solar tide, and the eight disturbances already analyzed out of the tide-gauge curve by the harmonic analyzer. one end of the string is fixed, the other carries a pencil which writes a trace on a revolving drum of paper--a trace which represents the combined motion of all the pulleys, and so predicts the exact height of the tide at the place, at any future time you like. the machine can be turned quite quickly, so that a year's tides can be run off with every detail in about half-an-hour. this is the easiest part of the operation. nothing has to be done but to keep it supplied with paper and pencil, and turn a handle as if it were a coffee-mill instead of a tide-mill. (figs. 119 and 120.) [illustration: fig. 118.--harmonic analyzer; for analyzing out the constituents from a set of observational curves.] my subject is not half exhausted. i might go on to discuss the question of tidal energy--whether it can be ever utilized for industrial purposes; and also the very interesting question whence it comes. tidal energy is almost the only terrestrial form of energy that does not directly or indirectly come from the sun. the energy of tides is now known to be obtained at the expense of the earth's rotation; and accordingly our day must be slowly, very slowly, lengthening. the tides of past ages have destroyed the moon's rotation, and so it always turns the same face to us. there is every reason to believe that in geologic ages the moon was nearer to us than it is now, and that accordingly our tides were then far more violent, rising some hundreds of feet instead of twenty or thirty, and sweeping every six hours right over the face of a country, ploughing down hills, denuding rocks, and producing a copious sedimentary deposit. [illustration: fig. 119.--tide-predicter, for combining the ascertained constituents into a tidal curve for the future.] in thus discovering the probable violent tides of past ages, astronomy has, within the last few years, presented geology with the most powerful denuding agent known; and the study of the earth's past history cannot fail to be greatly affected by the modern study of the intricate and refined conditions attending prolonged tidal action on incompletely rigid bodies. [read on this point the last chapter of sir r. ball's _story of the heavens_.] [illustration: fig. 120.--weekly sheet of curves. tides for successive days are predicted on the same sheet of paper, to economise space.] i might also point out that the magnitude of our terrestrial tides enables us to answer the question as to the internal fluidity of the earth. it used to be thought that the earth's crust was comparatively thin, and that it contained a molten interior. we now know that this is not the case. the interior of the earth is hot indeed, but it is not fluid. or at least, if it be fluid, the amount of fluid is but very small compared with the thickness of the unyielding crust. all these, and a number of other most interesting questions, fringe the subject of the tides; the theoretical study of which, started by newton, has developed, and is destined in the future to further develop, into one of the most gigantic and absorbing investigations--having to do with the stability or instability of solar systems, and with the construction and decay of universes. these theories are the work of pioneers now living, whose biographies it is therefore unsuitable for us to discuss, nor shall i constantly mention their names. but helmholtz, and thomson, are household words, and you well know that in them and their disciples the race of pioneers maintains its ancient glory. notes for lecture xviii tides are due to incomplete rigidity of bodies revolving round each other under the action of gravitation, and at the same time spinning on their axes. two spheres revolving round each other can only remain spherical if rigid; if at all plastic they become prolate. if either rotate on its axis, in the same or nearly the same plane as it revolves, that one is necessarily subject to tides. the axial rotation tends to carry the humps with it, but the pull of the other body keeps them from moving much. hence the rotation takes place against a pull, and is therefore more or less checked and retarded. this is the theory of von helmholtz. the attracting force between two such bodies is no longer _exactly_ towards the centre of revolution, and therefore kepler's second law is no longer precisely obeyed: the rate of description of areas is subject to slight acceleration. the effect of this tangential force acting on the tide-compelling body is gradually to increase its distance from the other body. applying these statements to the earth and moon, we see that tidal energy is produced at the expense of the earth's rotation, and that the length of the day is thereby slowly increasing. also that the moon's rotation relative to the earth has been destroyed by past tidal action in it (the only residue of ancient lunar rotation now being a scarcely perceptible libration), so that it turns always the same face towards us. moreover, that its distance from the earth is steadily increasing. this last is the theory of professor g.h. darwin. long ago the moon must therefore have been much nearer the earth, and the day was much shorter. the tides were then far more violent. halving the distance would make them eight times as high; quartering it would increase them sixty-four-fold. a most powerful geological denuding agent. trade winds and storms were also more violent. if ever the moon were close to the earth, it would have to revolve round it in about three hours. if the earth rotated on its axis in three hours, when fluid or pasty, it would be unstable, and begin to separate a portion of itself as a kind of bud, which might then get detached and gradually pushed away by the violent tidal action. hence it is possible that this is the history of the moon. if so, it is probably an exceptional history. the planets were not formed from the sun in this way. mars' moons revolve round him more quickly than the planet rotates: hence with them the process is inverted, and they must be approaching him and may some day crash along his surface. the inner moon is now about 4,000 miles away, and revolves in 7-1/2 hours. it appears to be about 20 miles in diameter, and weighs therefore, if composed of rock, 40 billion tons. mars rotates in 24-1/2 hours. a similar fate may _possibly_ await our moon ages hence--by reason of the action of terrestrial tides produced by the sun. lecture xviii the tides, and planetary evolution in the last lecture we considered the local peculiarities of the tides, the way in which they were formed in open ocean under the action of the moon and the sun, and also the means by which their heights and times could be calculated and predicted years beforehand. towards the end i stated that the subject was very far from being exhausted, and enumerated some of the large and interesting questions which had been left untouched. it is with some of these questions that i propose now to deal. i must begin by reminding you of certain well-known facts, a knowledge of which i may safely assume. and first we must remind ourselves of the fact that almost all the rocks which form the accessible crust of the earth were deposited by the agency of water. nearly all are arranged in regular strata, and are composed of pulverized materials--materials ground down from pre-existing rocks by some denuding and grinding action. they nearly all contain vestiges of ancient life embedded in them, and these vestiges are mainly of marine origin. the strata which were once horizontal are now so no longer--they have been tilted and upheaved, bent and distorted, in many places. some of them again have been metamorphosed by fire, so that their organic remains have been destroyed, and the traces of their aqueous origin almost obliterated. but still, to the eye of the geologist, all are of aqueous or sedimentary origin: roughly speaking, one may say they were all deposited at the bottom of some ancient sea. the date of their formation no man yet can tell, but that it was vastly distant is certain. for the geological era is not over. aqueous action still goes on: still does frost chip the rocks into fragments; still do mountain torrents sweep stone and mud and _débris_ down the gulleys and watercourses; still do rivers erode their channels, and carry mud and silt far out to sea. and, more powerful than any of these agents of denudation, the waves and the tides are still at work along every coast-line, eating away into the cliffs, undermining gradually and submerging acre after acre, and making with the refuse a shingly, or a sandy, or a muddy beach--the nucleus of a new geological formation. of all denuding agents, there can be no doubt that, to the land exposed to them, the waves of the sea are by far the most powerful. think how they beat and tear, and drive and drag, until even the hardest rock, like basalt, becomes honeycombed into strange galleries and passages--fingal's cave, for instance--and the softer parts are crumbled away. but the area now exposed to the teeth of the waves is not great. the fury of a winter storm may dash them a little higher than usual, but they cannot reach cliffs 100 feet high. they can undermine such cliffs indeed, and then grind the fragments to powder, but their direct action is limited. not so limited, however, as they would be without the tides. consider for a moment the denudation import of the tides: how does the existence of tidal rise and fall affect the geological problem? the scouring action of the tidal currents themselves is not to be despised. it is the tidal ebb and flow which keeps open channel in the mersey, for instance. but few places are so favourably situated as liverpool in this respect, and the direct scouring action of the tides in general is not very great. their geological import mainly consists in this--that they raise and lower the surface waves at regular intervals, so as to apply them to a considerable stretch of coast. the waves are a great planing machine attacking the land, and the tides raise and lower this planing machine, so that its denuding tooth is applied, now twenty feet vertically above mean level, now twenty feet below. making all allowance for the power of winds and waves, currents, tides, and watercourses, assisted by glacial ice and frost, it must be apparent how slowly the work of forming the rocks is being carried on. it goes on steadily, but so slowly that it is estimated to take 6000 years to wear away one foot of the american continent by all the denuding causes combined. to erode a stratum 5000 feet thick will require at this rate thirty million years. the age of the earth is not at all accurately known, but there are many grounds for believing it not to be much older than some thirty million years. that is to say, not greatly more than this period of time has elapsed since it was in a molten condition. it may be as old as a hundred million years, but its age is believed by those most competent to judge to be more likely within this limit than beyond it. but if we ask what is the thickness of the rocks which in past times have been formed, and denuded, and re-formed, over and over again, we get an answer, not in feet, but in miles. the laurentian and huronian rocks of canada constitute a stratum ten miles thick; and everywhere the rocks at the base of our stratified system are of the most stupendous volume and thickness. it has always been a puzzle how known agents could have formed these mighty masses, and the only solution offered by geologists was, unlimited time. given unlimited time, they could, of course, be formed, no matter how slowly the process went on. but inasmuch as the time allowable since the earth was cool enough for water to exist on it except as steam is not by any means unlimited, it becomes necessary to look for a far more powerful engine than any now existing; there must have been some denuding agent in those remote ages--ages far more distant from us than the carboniferous period, far older than any forms of life, fossil or otherwise, ages among the oldest known to geology--a denuding agent must have then existed, far more powerful than any we now know. such an agent it has been the privilege of astronomy and physics, within the last ten years, to discover. to this discovery i now proceed to lead up. our fundamental standard of time is the period of the earth's rotation--the length of the day. the earth is our one standard clock: all time is expressed in terms of it, and if it began to go wrong, or if it did not go with perfect uniformity, it would seem a most difficult thing to discover its error, and a most puzzling piece of knowledge to utilize when found. that it does not go much wrong is proved by the fact that we can calculate back to past astronomical events--ancient eclipses and the like--and we find that the record of their occurrence, as made by the old magi of chaldæa, is in very close accordance with the result of calculation. one of these famous old eclipses was observed in babylon about thirty-six centuries ago, and the chaldæan astronomers have put on record the time of its occurrence. modern astronomers have calculated back when it should have occurred, and the observed time agrees very closely with the actual, but not exactly. why not exactly? partly because of the acceleration of the moon's mean motion, as explained in the lecture on laplace (p. 262). the orbit of the earth was at that time getting rounder, and so, as a secondary result, the speed of the moon was slightly increasing. it is of the nature of a perturbation, and is therefore a periodic not a progressive or continuous change, and in a sufficiently long time it will be reversed. still, for the last few thousand years the moon's motion has been, on the whole, accelerated (though there seems to be a very slight retarding force in action too). laplace thought that this fact accounted for the whole of the discrepancy; but recently, in 1853, professor adams re-examined the matter, and made a correction in the details of the theory which diminishes its effect by about one-half, leaving the other half to be accounted for in some other way. his calculations have been confirmed by professor cayley. this residual discrepancy, when every known cause has been allowed for, amounts to about one hour. the eclipse occurred later than calculation warrants. now this would have happened from either of two causes, either an acceleration of the moon in her orbit, or a retardation of the earth in her diurnal rotation--a shortening of the month or a lengthening of the day, or both. the total discrepancy being, say, two hours, an acceleration of six seconds-per-century per century will in thirty-six centuries amount to one hour; and this, according to the corrected laplacian theory, is what has occurred. but to account for the other hour some other cause must be sought, and at present it is considered most probably due to a steady retardation of the earth's rotation--a slow, very slow, lengthening of the day. the statement that a solar eclipse thirty-six centuries ago was an hour late, means that a place on the earth's surface came into the shadow one hour behind time--that is, had lagged one twenty-fourth part of a revolution. the earth, therefore, had lost this amount in the course of 3600 × 365-1/4 revolutions. the loss per revolution is exceedingly small, but it accumulates, and at any era the total loss is the sum of all the losses preceding it. it may be worth while just to explain this point further. suppose the earth loses a small piece of time, which i will call an instant, per day; a locality on the earth will come up to a given position one instant late on the first day after an event. on the next day it would come up two instants late by reason of the previous loss; but it also loses another instant during the course of the second day, and so the total lateness by the end of that day amounts to three instants. the day after, it will be going slower from the beginning at the rate of two instants a day, it will lose another instant on the fresh day's own account, and it started three instants late; hence the aggregate loss by the end of the third day is 1 + 2 + 3 = 6. by the end of the fourth day the whole loss will be 1 + 2 + 3 + 4, and so on. wherefore by merely losing one instant every day the total loss in _n_ days is (1 + 2 + 3 + ... + _n_) instants, which amounts to 1/2_n_ (_n_ + 1) instants; or practically, when _n_ is big, to 1/2n^2. now in thirty-six centuries there have been 3600 × 365-1/4 days, and the total loss has amounted to an hour; hence the length of "an instant," the loss per diem, can be found from the equation 1/2(3600 × 365)^2 instants = 1 hour; whence one "instant" equals the 240 millionth part of a second. this minute quantity represents the retardation of the earth per day. in a year the aggregate loss mounts up to 1/3600th part of a second, in a century to about three seconds, and in thirty-six centuries to an hour. but even at the end of the thirty-six centuries the day is barely any longer; it is only 3600 × 365 instants, that is 1/180th of a second, longer than it was at the beginning. and even a million years ago, unless the rate of loss was different (as it probably was), the day would only be thirty-five minutes shorter, though by that time the aggregate loss, as measured by the apparent lateness of any perfectly punctual event reckoned now, would have amounted to nine years. (these numbers are to be taken as illustrative, not as precisely representing terrestrial fact.) what can have caused the slowing down? swelling of the earth by reason of accumulation of meteoric dust might do something, but probably very little. contraction of the earth as it goes on cooling would act in the opposite direction, and probably more than counterbalance the dust effect. the problem is thus not a simple one, for there are several disturbing causes, and for none of them are the data enough to base a quantitative estimate upon; but one certain agent in lengthening the day, and almost certainly the main agent, is to be found in the tides. remember that the tidal humps were produced as the prolateness of a sphere whirled round and round a fixed centre, like a football whirled by a string. these humps are pulled at by the moon, and the earth rotates on its axis against this pull. hence it tends to be constantly, though very slightly, dragged back. in so far as the tidal wave is allowed to oscillate freely, it will swing with barely any maintaining force, giving back at one quarter-swing what it has received at the previous quarter; but in so far as it encounters friction, which it does in all channels where there is an actual ebb and flow of the water, it has to receive more than it gives back, and the balance of energy has to be made up to it, or the tides would cease. the energy of the tides is, in fact, continually being dissipated by friction, and all the energy so dissipated is taken from the rotation of the earth. if tidal energy were utilized by engineers, the machines driven would be really driven at the expense of the earth's rotation: it would be a mode of harnessing the earth and using the moon as fixed point or fulcrum; the moon pulling at the tidal protuberance, and holding it still as the earth rotates, is the mechanism whereby the energy is extracted, the handle whereby the friction brake is applied. winds and ocean currents have no such effect (as mr. fronde in _oceania_ supposes they have), because they are all accompanied by a precisely equal counter-current somewhere else, and no internal rearrangement of fluid can affect the motion of a mass as a whole; but the tides are in different case, being produced, not by internal inequalities of temperature, but by a straightforward pull from an external body. the ultimate effect of tidal friction and dissipation of energy will, therefore, be to gradually retard the earth till it does not rotate with reference to the moon, _i.e._ till it rotates once while the moon revolves once; in other words, to make the day and the month equal. the same cause must have been in operation, but with eighty-fold greater intensity, on the moon. it has ceased now, because the rotation has stopped, but if ever the moon rotated on its axis with respect to the earth, and if it were either fluid itself or possessed any liquid ocean, then the tides caused by the pull of the earth must have been prodigious, and would tend to stop its rotation. have they not succeeded? is it not probable that this is _why_ the moon always now turns the same face towards us? it is believed to be almost certainly the cause. if so, there was a time when the moon behaved differently--when it rotated more quickly than it revolved, and exhibited to us its whole surface. and at this era, too, the earth itself must have rotated a little faster, for it has been losing speed ever since. we have thus arrived at this fact, that a thousand years ago the day was a trifle shorter than it is now. a million years ago it was, perhaps, an hour shorter. twenty million years ago it must have been much shorter. fifty million years ago it may have been only a few hours long. the earth may have spun round then quite quickly. but there is a limit. if it spun too fast it would fly to pieces. attach shot by means of wax to the whirling earth model, fig. 110, and at a certain speed the cohesion of the wax cannot hold them, so they fly off. the earth is held together not by cohesion but by gravitation; it is not difficult to reckon how fast the earth must spin for gravity at its surface to be annulled, and for portions to fly off. we find it about one revolution in three hours. this is a critical speed. if ever the day was three hours long, something must have happened. the day can never have been shorter than that; for if it were, the earth would have a tendency to fly in pieces, or, at least, to separate into two pieces. remember this, as a natural result of a three-hour day, which corresponds to an unstable state of things; remember also that in some past epoch a three-hour day is a probability. if we think of the state of things going on in the earth's atmosphere, if it had an atmosphere at that remote date, we shall recognize the existence of the most fearful tornadoes. the trade winds, which are now peaceful agents of commerce, would then be perpetual hurricanes, and all the denudation agents of the geologist would be in a state of feverish activity. so, too, would the tides: instead of waiting six hours between low and high tide, we should have to wait only three-quarters of an hour. every hour-and-a-half the water would execute a complete swing from high tide to high again. very well, now leave the earth, and think what has been happening to the moon all this while. we have seen that the moon pulls the tidal hump nearest to it back; but action and reaction are always equal and opposite--it cannot do that without itself getting pulled forward. the pull of the earth on the moon will therefore not be quite central, but will be a little in advance of its centre; hence, by kepler's second law, the rate of description of areas by its radius vector cannot be constant, but must increase (p. 208). and the way it increases will be for the radius vector to lengthen, so as to sweep out a bigger area. or, to put it another way, the extra speed tending to be gained by the moon will fling it further away by extra centrifugal force. this last is not so good a way of regarding the matter; though it serves well enough for the case of a ball whirled at the end of an elastic string. after having got up the whirl, the hand holding the string may remain almost fixed at the centre of the circle, and the motion will continue steadily; but if the hand be moved so as always to pull the string a little in advance of the centre, the speed of whirl will increase, the elastic will be more and more stretched, until the whirling ball is describing a much larger circle. but in this case it will likewise be going faster--distance and speed increase together. this is because it obeys a different law from gravitation--the force is not inversely as the square, or any other single power, of the distance. it does not obey any of kepler's laws, and so it does not obey the one which now concerns us, viz. the third; which practically states that the further a planet is from the centre the slower it goes; its velocity varies inversely with the square root of its distance (p. 74). if, instead of a ball held by elastic, it were a satellite held by gravity, an increase in distance must be accompanied by a diminution in speed. the time of revolution varies as the square of the cube root of the distance (kepler's third law). hence, the tidal reaction on the moon, having as its primary effect, as we have seen, the pulling the moon a little forward, has also the secondary or indirect effect of making it move slower and go further off. it may seem strange that an accelerating pull, directed in front of the centre, and therefore always pulling the moon the way it is going, should retard it; and that a retarding force like friction, if such a force acted, should hasten it, and make it complete its orbit sooner; but so it precisely is. gradually, but very slowly, the moon is receding from us, and the month is becoming longer. the tides of the earth are pushing it away. this is not a periodic disturbance, like the temporary acceleration of its motion discovered by laplace, which in a few centuries, more or less, will be reversed; it is a disturbance which always acts one way, and which is therefore cumulative. it is superposed upon all periodic changes, and, though it seems smaller than they, it is more inexorable. in a thousand years it makes scarcely an appreciable change, but in a million years its persistence tells very distinctly; and so, in the long run, the month is getting longer and the moon further off. working backwards also, we see that in past ages the moon must have been nearer to us than it is now, and the month shorter. now just note what the effect of the increased nearness of the moon was upon our tides. remember that the tide-generating force varies inversely as the cube of distance, wherefore a small change of distance will produce a great difference in the tide-force. the moon's present distance is 240 thousand miles. at a time when it was only 190 thousand miles, the earth's tides would have been twice as high as they are now. the pushing away action was then a good deal more violent, and so the process went on quicker. the moon must at some time have been just half its present distance, and the tides would then have risen, not 20 or 30 feet, but 160 or 200 feet. a little further back still, we have the moon at one-third of its present distance from the earth, and the tides 600 feet high. now just contemplate the effect of a 600-foot tide. we are here only about 150 feet above the level of the sea; hence, the tide would sweep right over us and rush far away inland. at high tide we should have some 200 feet of blue water over our heads. there would be nothing to stop such a tide as that in this neighbourhood till it reached the high lands of derbyshire. manchester would be a seaport then with a vengeance! the day was shorter then, and so the interval between tide and tide was more like ten than twelve hours. accordingly, in about five hours, all that mass of water would have swept back again, and great tracts of sand between here and ireland would be left dry. another five hours, and the water would come tearing and driving over the country, applying its furious waves and currents to the work of denudation, which would proceed apace. these high tides of enormously distant past ages constitute the denuding agent which the geologist required. they are very ancient--more ancient than the carboniferous period, for instance, for no trees could stand the furious storms that must have been prevalent at this time. it is doubtful whether any but the very lowest forms of life then existed. it is the strata at the bottom of the geological scale that are of the most portentous thickness, and the only organism suspected in them is the doubtful _eozoon canadense_. sir robert ball believes, and several geologists agree with him, that the mighty tides we are contemplating may have been coæval with this ancient laurentian formation, and others of like nature with it. but let us leave geology now, and trace the inverted progress of events as we recede in imagination back through the geological era, beyond, into the dim vista of the past, when the moon was still closer and closer to the earth, and was revolving round it quicker and quicker, before life or water existed on it, and when the rocks were still molten. suppose the moon once touched the earth's surface, it is easy to calculate, according to the principles of gravitation, and with a reasonable estimate of its size as then expanded by heat, how fast it must then have revolved round the earth, so as just to save itself from falling in. it must have gone round once every three hours. the month was only three hours long at this initial epoch. remember, however, the initial length of the day. we found that it was just possible for the earth to rotate on its axis in three hours, and that when it did so, something was liable to separate from it. here we find the moon in contact with it, and going round it in this same three-hour period. surely the two are connected. surely the moon was a part of the earth, and was separating from it. that is the great discovery--the origin of the moon. once, long ages back, at date unknown, but believed to be certainly as much as fifty million years ago, and quite possibly one hundred million, there was no moon, only the earth as a molten globe, rapidly spinning on its axis--spinning in about three hours. gradually, by reason of some disturbing causes, a protuberance, a sort of bud, forms at one side, and the great inchoate mass separates into two--one about eighty times as big as the other. the bigger one we now call earth, the smaller we now call moon. round and round the two bodies went, pulling each other into tremendously elongated or prolate shapes, and so they might have gone on for a long time. but they are unstable, and cannot go on thus: they must either separate or collapse. some disturbing cause acts again, and the smaller mass begins to revolve less rapidly. tides at once begin--gigantic tides of molten lava hundreds of miles high; tides not in free ocean, for there was none then, but in the pasty mass of the entire earth. immediately the series of changes i have described begins, the speed of rotation gets slackened, the moon's mass gets pushed further and further away, and its time of revolution grows rapidly longer. the changes went on rapidly at first, because the tides were so gigantic; but gradually, and by slow degrees, the bodies get more distant, and the rate of change more moderate. until, after the lapse of ages, we find the day twenty-four hours long, the moon 240,000 miles distant, revolving in 27-1/3 days, and the tides only existing in the water of the ocean, and only a few feet high. this is the era we call "to-day." the process does not stop here: still the stately march of events goes on; and the eye of science strives to penetrate into the events of the future with the same clearness as it has been able to descry the events of the past. and what does it see? it will take too long to go into full detail: but i will shortly summarize the results. it sees this first--the day and the month both again equal, but both now about 1,400 hours long. neither of these bodies rotating with respect to each other--the two as if joined by a bar--and total cessation of tide-generating action between them. the date of this period is one hundred and fifty millions of years hence, but unless some unforeseen catastrophe intervenes, it must assuredly come. yet neither will even this be the final stage; for the system is disturbed by the tide-generating force of the sun. it is a small effect, but it is cumulative; and gradually, by much slower degrees than anything we have yet contemplated, we are presented with a picture of the month getting gradually shorter than the day, the moon gradually approaching instead of receding, and so, incalculable myriads of ages hence, precipitating itself upon the surface of the earth whence it arose. such a catastrophe is already imminent in a neighbouring planet--mars. mars' principal moon circulates round him at an absurd pace, completing a revolution in 7-1/2 hours, and it is now only 4,000 miles from his surface. the planet rotates in twenty-four hours as we do; but its tides are following its moon more quickly than it rotates after them; they are therefore tending to increase its rate of spin, and to retard the revolution of the moon. mars is therefore slowly but surely pulling its moon down on to itself, by a reverse action to that which separated our moon. the day shorter than the month forces a moon further away; the month shorter than the day tends to draw a satellite nearer. this moon of mars is not a large body: it is only twenty or thirty miles in diameter, but it weighs some forty billion tons, and will ultimately crash along the surface with a velocity of 8,000 miles an hour. such a blow must produce the most astounding effects when it occurs, but i am unable to tell you its probable date. so far we have dealt mainly with the earth and its moon; but is the existence of tides limited to these bodies? by no means. no body in the solar system is rigid, no body in the stellar universe is rigid. all must be susceptible of some tidal deformation, and hence, in all of them, agents like those we have traced in the history of the earth and moon must be at work: the motion of all must be complicated by the phenomena of tides. it is prof. george darwin who has worked out the astronomical influence of the tides, on the principles of sir william thomson: it is sir robert ball who has extended mr. darwin's results to the past history of our own and other worlds.[32] tides are of course produced in the sun by the action of the planets, for the sun rotates in twenty-five days or thereabouts, while the planets revolve in much longer periods than that. the principal tide-generating bodies will be venus and jupiter; the greater nearness of one rather more than compensating for the greater mass of the other. it may be interesting to tabulate the relative tide-producing powers of the planets on the sun. they are as follows, calling that of the earth 1,000:- relative tide-producing powers of the planets on the sun. mercury 1,121 venus 2,339 earth 1,000 mars 304 jupiter 2,136 saturn 1,033 uranus 21 neptune 9 the power of all of them is very feeble, and by acting on different sides they usually partly neutralize each other's action; but occasionally they get all on one side, and in that case some perceptible effect may be produced; the probable effect seems likely to be a gentle heaving tide in the solar surface, with breaking up of any incipient crust; and such an effect may be considered as evidenced periodically by the great increase in the number of solar spots which then break out. the solar tides are, however, much too small to appreciably push any planet away, hence we are not to suppose that the planets originated by budding from the sun, in contradiction of the nebular hypothesis. nor is it necessary to assume that the satellites, as a class, originated in the way ours did; though they may have done so. they were more probably secondary rings. our moon differs from other satellites in being exceptionally large compared with the size of its primary; it is as big as some of the moons of jupiter and saturn. the earth is the only one of the small planets that has an appreciable moon, and hence there is nothing forced or unnatural in supposing that it may have had an exceptional history. evidently, however, tidal phenomena must be taken into consideration in any treatment of the solar system through enormous length of time, and it will probably play a large part in determining its future. when laplace and lagrange investigated the question of the stability or instability of the solar system, they did so on the hypothesis that the bodies composing it were rigid. they reached a grand conclusion--that all the mutual perturbations of the solar system were periodic--that whatever changes were going on would reach a maximum and then begin to diminish; then increase again, then diminish, and so on. the system was stable, and its changes were merely like those of a swinging pendulum. but this conclusion is not final. the hypothesis that the bodies are rigid is not strictly true: and directly tidal deformation is taken into consideration it is perceived to be a potent factor, able in the long run to upset all their calculations. but it is so utterly and inconceivably minute--it only produces an appreciable effect after millions of years--whereas the ordinary perturbations go through their swings in some hundred thousand years or so at the most. granted it is small, but it is terribly persistent; and it always acts in one direction. never does it cease: never does it begin to act oppositely and undo what it has done. it is like the perpetual dropping of water. there may be only one drop in a twelvemonth, but leave it long enough, and the hardest stone must be worn away at last. * * * * * we have been speaking of millions of years somewhat familiarly; but what, after all, is a million years that we should not speak familiarly of it? it is longer than our lifetime, it is true. to the ephemeral insects whose lifetime is an hour, a year might seem an awful period, the mid-day sun might seem an almost stationary body, the changes of the seasons would be unknown, everything but the most fleeting and rapid changes would appear permanent and at rest. conversely, if our life-period embraced myriads of æons, things which now seem permanent would then appear as in a perpetual state of flux. a continent would be sometimes dry, sometimes covered with ocean; the stars we now call fixed would be moving visibly before our eyes; the earth would be humming on its axis like a top, and the whole of human history might seem as fleeting as a cloud of breath on a mirror. evolution is always a slow process. to evolve such an animal as a greyhound from its remote ancestors, according to mr. darwin, needs immense tracts of time; and if the evolution of some feeble animal crawling on the surface of this planet is slow, shall the stately evolution of the planetary orbs themselves be hurried? it may be that we are able to trace the history of the solar system for some thousand million years or so; but for how much longer time must it not have a history--a history, and also a future--entirely beyond our ken? those who study the stars have impressed upon them the existence of the most immeasurable distances, which yet are swallowed up as nothing in the infinitude of space. no less are we compelled to recognize the existence of incalculable æons of time, and yet to perceive that these are but as drops in the ocean of eternity. footnotes: [1] the following account of mars's motion is from the excellent small manual of astronomy by dr. haughton of trinity college, dublin:--(p. 151) "mars's motion is very unequal; when he first appears in the morning emerging from the rays of the sun, his motion is direct and rapid; it afterwards becomes slower, and he becomes stationary when at an elongation of 137° from the sun; then his motion becomes retrograde, and its velocity increases until he is in opposition to the sun at 180°; at this time the retrograde motion is most rapid, and afterwards diminishes until he is 137° distant from the sun on the other side, when mars again becomes stationary; his motion then becomes direct, and increases in velocity until it reaches a maximum, when the planet is again in conjunction with the sun. the retrograde motion of this planet lasts for 73 days: and its arc of retrogradation is 16°." [2] it is not so easy to plot the path of the sun among the stars by direct observation, as it is to plot the path of a planet; because sun and stars are not visible together. hipparchus used the moon as an intermediary; since sun and moon are visible together, and also moon and stars. [3] this is, however, by no means the whole of the matter. the motion is not a simple circle nor has it a readily specifiable period. there are several disturbing causes. all that is given here is a first rough approximation. [4] the proof is easy, and ought to occur in books on solid geometry. by a "regular" solid is meant one with all its faces, edges, angles, &c., absolutely alike: it is of these perfectly symmetrical bodies that there are only five. crystalline forms are practically infinite in number. [5] best known to us by his christian name, as so many others of that time are known, _e.g._ raphael sanzio, dante alighieri, michael angelo buonarotti. the rule is not universal. tasso and ariosto are surnames. [6] it would seem that the fact that all bodies of every material tend to fall at the same rate is still not clearly known. confusion is introduced by the resistance of the air. but a little thought should make it clear that the effect of the air is a mere disturbance, to be eliminated as far as possible, since the atmosphere has nothing to do with gravitation. the old fashioned "guinea and feather experiment" illustrates that in a vacuum things entirely different in specific gravity or surface drop at the same pace. [7] karl von gebler (galileo), p. 13. [8] it is of course the "silver lining" of clouds that outside observers see. [9] l.u.k., _life of galileo_, p. 26. [10] _note added september, 1892._ news from the lick observatory makes a very small fifth satellite not improbable. [11] they remained there till this century. in 1835 they were quietly dropped. [12] it was invented by van helmont, a belgian chemist, who died in 1644. he suggested two names _gas_ and _blas_, and the first has survived. blas was, i suppose, from _blasen_, to blow, and gas seems to be an attempt to get at the sanskrit root underlying all such words as _geist_. [13] such as this, among many others:--the duration of a flame under different conditions is well worth determining. a spoonful of warm spirits of wine burnt 116 pulsations. the same spoonful of spirits of wine with addition of one-sixth saltpetre burnt 94 pulsations. with one-sixth common salt, 83; with one-sixth gunpowder, 110; a piece of wax in the middle of the spirit, 87; a piece of _kieselstein_, 94; one-sixth water, 86; and with equal parts water, only 4 pulse-beats. this, says liebig, is given as an example of a "_licht-bringende versuch_." [14] draper, _history of civilization in europe_, vol. ii. p. 259. [15] professor knight's series of philosophical classics. [16] to explain why the entire system, horse and cart together, move forward, the forces acting on the ground must be attended to. [17] the distance being proportional to the _square_ of the time, see p. 82. [18] the following letter, recently unearthed and published in _nature_, may 12, 1881, seems to me well worth preserving. the feeling of a respiratory interval which it describes is familiar to students during the too few periods of really satisfactory occupation. the early guess concerning atmospheric electricity is typical of his extraordinary instinct for guessing right. "london, _dec. 15, 1716_. "dear doctor,--he that in ye mine of knowledge deepest diggeth, hath, like every other miner, ye least breathing time, and must sometimes at least come to terr. alt. for air. "in one of these respiratory intervals i now sit down to write to you, my friend. "you ask me how, with so much study, i manage to retene my health. ah, my dear doctor, you have a better opinion of your lazy friend than he hath of himself. morpheous is my last companion; without 8 or 9 hours of him yr correspondent is not worth one scavenger's peruke. my practices did at ye first hurt my stomach, but now i eat heartily enou' as y' will see when i come down beside you. "i have been much amused at ye singular [greek: _phenomena_] resulting from bringing of a needle into contact with a piece of amber or resin fricated on silke clothe. ye flame putteth me in mind of sheet lightning on a small--how very small--scale. but i shall in my epistles abjure philosophy whereof when i come down to sakly i'll give you enou'. i began to scrawl at 5 mins. from 9 of ye clk. and have in writing consmd. 10 mins. my ld. somerset is announced. "farewell, gd. bless you and help yr sincere friend. "isaac newton. "_to_ dr. law, suffolk." [19] kepler's laws may be called respectively, the law of path, the law of speed, and the relationship law. by the "mass" of a body is meant the number of pounds or tons in it: the amount of matter it contains. the idea is involved in the popular word "massive." [20] the equation we have to verify is 4[pi]^2r^3 gr^2 = -----------, t^2 with the data that _r_, the moon's distance, is 60 times r, the earth's radius, which is 3,963 miles; while t, the time taken to complete the moon's orbit, is 27 days, 13 hours, 18 minutes, 37 seconds. hence, suppose we calculate out _g_, the intensity of terrestrial gravity, from the above equation, we get 4[pi]^2 39·92 × 216000 × 3963 miles _g_ = ---------× (60)^3r = ---------------------------- t (27 days, 13 hours, &c.)^2 = 32·57 feet-per-second per second, which is not far wrong. [21] the two motions may be roughly compounded into a single motion, which for a few centuries may without much error be regarded as a conical revolution about a different axis with a different period; and lieutenant-colonel drayson writes books emphasizing this simple fact, under the impression that it is a discovery. [22] members of the accademia dei lyncei, the famous old scientific society established in the time of cosmo de medici--older than our own royal society. [23] newton suspected that the moon really did so oscillate, and so it may have done once; but any real or physical libration, if existing at all, is now extremely minute. [24] an interesting picture in the new gallery this year (1891), attempting to depict "earth-rise in moon-land," unfortunately errs in several particulars. first of all, the earth does not "rise," but is fixed relatively to each place on the moon; and two-fifths of the moon never sees it. next, the earth would not look like a map of the world with a haze on its edge. lastly, whatever animal remains the moon may contain would probably be rather in the form of fossils than of skeletons. the skeleton is of course intended as an image of death and desolation. it is a matter of taste: but a skeleton, it seems to me, speaks too recently of life to be as appallingly weird and desolate as a blank stone or ice landscape, unshaded by atmosphere or by any trace of animal or plant life, could be made. [25] five of jupiter's revolutions occupy 21,663 days; two of saturn's revolutions occupy 21,526 days. [26] _excircularity_ is what is meant by this term. it is called "excentricity" because the foci (not the centre) of an ellipse are regarded as the representatives of the centre of a circle. their distance from the centre, compared with the radius of the unflattened circle, is called the excentricity. [27] a curve of the _n_th degree has 1/2_n_(_n_+3) arbitrary constants in its equation, hence this number of points specifically determine it. but special points, like focus or vertex, count as two ordinary ones. hence three points plus the focus act as five points, and determine a conic or curve of the second degree. three observations therefore fix an orbit round the sun. [28] its name suggests a measure of the diameter of the sun's disk, and this is one of its functions; but it can likewise measure planetary and other disks; and in general behaves as the most elaborate and expensive form of micrometer. the königsberg instrument is shewn in fig. 92. [29] it may be supposed that the terms "minute" and "second" have some necessary connection with time, but they are mere abbreviations for _partes minutæ_ and _partes minutæ secundæ_, and consequently may be applied to the subdivision of degrees just as properly as to the subdivision of hours. a "second" of arc means the 3600th part of a degree, just as a second of time means the 3600th part of an hour. [30] a group of flying particles, each one invisible, obstructs light singularly little, even when they are close together, as one can tell by the transparency of showers and snowstorms. the opacity of haze may be due not merely to dust particles, but to little eddies set up by radiation above each particle, so that the air becomes turbulent and of varying density. (see a similar suggestion by mr. poynting in _nature_, vol. 39, p. 323.) [31] the moon ought to be watched during the next great shower, if the line of fire happens to take effect on a visible part of the dark portion. [32] address to birmingham midland institute, "a glimpse through the corridors of time." index index a abbott, t.k., on tides, 369 adams, john couch, 193, 217, 302, 323, 324, 325, 327, 329, 330, 352, 385 airy, sir george, 193, 244, 302, 323, 324, 327, 367 anaxagoras, 15 appian, 218 arabs, the, form a link between the old and new science, 9 archimedes, 7, 8, 84, 87, 144, 177 aristarchus, 34 aristotle, 66, 69, 88, 94, 99, 167. he taught that the earth was a sphere, 16; his theories did not allow of the earth's motion, 34; he was regarded as inspired, 89 b bacon, francis, 142, 143, 144, 145. his _novum organum_, 141 bacon, roger, 96, 139, 140. the herald of the dawn of science, 9 brahé, george, uncle of tycho brahé, 39 brahé, steno, brother of tycho brahé, 39 brahé, tycho, 37, 39, 40, 44, 45, 49, 51, 53, 54, 55, 58, 63, 64, 65, 66, 68, 71, 72, 74, 75, 77, 78, 86, 94, 117, 137, 155, 165, 166, 200, 244, 281, 288. he tried to adopt the main features of the copernican theory without admitting the motion of the earth, 37; he was a poor theorist but a great observer, 38; his medicine, 44; his personal history, 39, _seq._; his observatory, uraniburg, 47; his greatest invention, 50, note; his maniac lep, 52; his kindness to kepler, 63 ball, sir r., 391, 394; his _story of the heavens_, 377 barrow, dr., 165, 187 bessel, 288, 310, 311, 313, 315, 316, 318, 323 biela, 345, 346, 347 bode's law, 60, 296, 298, 299, 326 boyle, 139, 188 bradley, prof. james, 233, 246, 247, 249, 252, 253, 308, 319 bremiker, 328, 329 brewster, on kepler, 78 brinkley, 308 bruno, giordano, 108, 127 c castelli, 112, 133 cayley, prof., 385 challis, prof., 328, 329 clairut, 193, 216, 217, 219, 234, 341 clark, alvan and sons, 316 columbus, 9, 144 copernicus, 7, 10, _seq._, 14, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38, 62, 66, 68, 70, 78, 93, 95, 100, 108, 111, 121, 122, 137, 155, 166, 223, 234, 247, 307; his _de revolutionibus orbium coelestium_, 11, 75, 138; he _proved_ that the earth went round the sun, 13; the influence of his theory on the church, 13, _seq._; his life-work summarised, 30; his life by mr. e.j.c. morton, 31 copernican tables, 40; copernican theory, 59, 60, 125, 144, 167 copernik, nicolas; see copernicus cornu, 238 croll, dr., his _climate and time_, 264 d d'alembert, 193, 234 darwin, charles, 134, 138, 397 darwin, prof. george, 367, 394 delambre, 253 descartes, 145, 146, 148, 151, 153, 156, 158, 164, 165, 167, 178, 181, 224, 227; his _discourse on method_, 142; his dream, 147; his system of algebraic geometry, 149, _seq._; his doctrine of vortices, 151, _seq._; his _principia mathematica_, 154; his life by mr. mahaffy, 154 e earth, the difficulties in the way of believing that it moved, 34, _seq._ "earth-rise in moon-land," 258, note encke, 345, 346 epicyclic orbits explained, 23, _seq._ equinoxes, their precession discovered by hipparchus, 27 eudoxus, 19 euler, 193, 234 f faraday, 84 fizeau, 238, 239 flamsteed, 215, 246, 284, 308, 319 fraunhofer, 311 froude, prof.; his _oceania_, 387 g galen, 87 galileo, galilei, 63, 75, 84, 88, 90, 92, 93, 97, 98, 101, 104, 106, 107, 108, 109, 110, 112, 114, 116, 117, 118, 120, 121, 122, 123, 125, 127, 133, 134, 137, 144, 145, 153, 154, 157, 165, 166, 167, 168, 177, 188, 200, 224, 227, 256, 281, 288, 309, 361; his youth, 85; his discovery of the pendulum, 86; his first observations about falling bodies, 88, _seq._; he invents a telescope, 95; he adopts the copernican theory, 94; he conceives "earth-shine," 100; he discovers jupiter's moons, 103; he studies saturn, 114, _seq._; his _dialogues on the ptolemaic and copernican systems_, 124; his abjuration, 130; he becomes blind, 132; he discovered the laws of motion, 167, _seq._; he guessed that sight was not instantaneous, 236, 237 galle, dr., 245, 329 gauss, 299, 300 gilbert, dr., 139, 140, 157, 188; his _de magnete_, 140, 144 greeks, their scientific methods, 7 groombridge's catalogue, 315 h hadley, 185 halley, 192, 193, 194, 195, 197, 215, 218, 219, 246, 258, 260, 261, 340, 341; he discovered the _principia_, 194 harvey, 144, 149 haughton, dr., 321; his manual on astronomy, 21, note heliometer, described, 311 helmholtz, 378 helmont, van, invented the word "gas," 141 henderson, 310, 314 herschel, alexander, 275, 277, 278, 279 herschel, caroline, 275, 276, 279, 286, 345; her journal quoted, 277, _seq._; her work with william h. described, 284 herschel, sir john, 283, 285, 327, 329 herschel, william, 185, 234, 235, 244, 249, 274, 275, 280, 281, 282, 284, 288, 289, 290, 293, 295, 305, 309, 310, 318, 319, 327; he "sweeps" the heavens, 280; his discovery of uranus, 281, 287; his artificial saturn, 281, 282; his methods of work with his sister, described, 284; he founded the science of astronomy, 287 hind, 300 hipparchus, 7, 18, 20, 27, 28, and note, 30, 40, 66, 223, 253; an explanation of his discovery of the precession of the equinoxes, 27, seq. hippocrates, 87 homeric cosmogony, 15, _seq._ hooke, 139, 188, 192, 193, 196, 197, 308 hôpital, marquis de l', 228 horkey, martin, 106 horrebow, 244 huxley, prof., 149 huyghens, 86, 166, 185 k kant, 267, 270 kelvin, lord, see thomson, sir w. kepler, john, 59, 60, 63, 64, 65, 66, 70, 72, 73, 75, 77, 79, 84, 93, 94, 95, 104, 106, 107, 110, 122, 137, 145, 153, 158, 164, 165, 166, 167, 192, 200, 208, 209, 210, 211, 212, 214, 218, 224, 227, 253, 256, 259, 260, 262, 288, 295, 296, 332, 338, 361, 389; he replaced epicycles by an ellipse, 27; he was a pupil of tycho brahé, 54; he was a speculator more than an observer, 58; his personal life, 58, _seq._; his theories about the numbers and distances of the planets, 60, 62; he was helped by tycho, 63; his main work, 65, _seq._; he gave up circular motion, 69; his _mysterium cosmographicon_, 105; his laws, 71, 74, 173, 174, 176, 179, 180, 206, _seq._ l lagrange, 193, 234, 255, 256, 257, 258, 263 lagrange and laplace, 258, 266, 395; they laid the foundations of the planetary theory, 259 laplace, 68, 193, 218, 234, 255, 261, 262, 267, 268, 269, 270, 272, 288, 301, 317, 384, 385, 390; his nebular hypothesis, 267, 292; his _mécanique céleste_, 323 lassell, mr., 283, 284 leibnitz, 192, 197, 233 le monnier, 319 leonardo, see vinci, leonardo da leverrier, 193, 327, 328, 329, 330, 352 lippershey, hans, 95 m maskelyne, 281 maxwell, clerk, 302, 303 molyneux, 248, 249 morton, mr. e.j. c, his life of copernicus, 31 n newton, prof. h.a., 347 newton, sir isaac, 7, 30, 79, 138, 139, 144, 145, 149, 153, 157, 158, 165, 166, 167, 174, 176, 184, 187, 188, 189, 191, 192, 194, 196, 198, 199, 201, 213, 216, 219, 220, 221, 224, 226, 227, 228, 233, 242, 253, 255, 256, 274, 288, 317, 340, 378; his _principia_, 191, 192, 193, 194, 195, 196, 197, 207, 214, 216, 218, 228, 233, 242, 253; his early life, 161, _seq._; his first experiments, 163; his work at cambridge, 164; his laws, 168; his application of the laws of gravity to astronomy, 177, 178, 179, 185, 190; his reticence, 178; his discoveries in optics, 181, _seq._; his work summarised, 186; his _optics_, 189; anecdotes of him, 191; his appearance in a court of justice, 195; some of his manuscripts very recently discovered, 217; his theories of the equinoxes and tides, 223, _seq._, 225, 363, _seq._ o olbers, 299, 300 p peters, prof., 300, 316 piazzi, 298, 299, 308, 313 picard, 190, 242, 244, 247 pioneers, genuine, 7 planets and days of the week, 18 poynting, 332 printing, 9 ptolemy, 18, 20, 27, 38, 153, 155, 166, 214; his system of the heavens simplified by copernicus, 11, 30; his system described, 19, _seq._; his system taught, 34; his harmonies, 74 pythagoras, 19, 20, 34 q quadrant, an early, 42, 43 r rheiter, 107 ricci, ostillio, 86, 87 roberts, isaac, 268 roemer, 239, 240, 242, 244, 249, 251, 308 rosse, lord, his telescope, 186, 268 rudolphine tables, 65 s scheiner, 107 sizzi, francesca, an orthodox astronomer, 106 snell, willebrod, and the law of refraction, 65 solar system, its fate, 265 stars, a list of, 307 struve, 308, 310, 311, 313 stuart, prof., quoted, 52 t tatius, 296 telescopes, early, 96 thales, 7, 140, 317 thomson, sir william, 367, 372, 373, 378, 394 tide-gauge, described, 373, _seq._ tides, 354, _seq._ time, is not exactly uniform, 384 torricelli, 133, 168 tycho, see brahé, tycho v vinci, leonardo da, 9, 100, 144, 184 viviani, 133, 168 voltaire, 181 w watson, prof., 300 whewell, 227 wren, sir christopher, 188, 192, 193, 197 z zach, von, 296, 299 zone of asteroids, 300, _seq._ the end. richard clay and sons, limited, london and bungay. autobiography of sir george biddell airy, k.c.b., m.a., ll.d., d.c.l., f.r.s., f.r.a.s., honorary fellow of trinity college, cambridge, astronomer royal from 1836 to 1881. edited by wilfrid airy, b.a., m.inst.c.e. 1896 preface. the life of airy was essentially that of a hard-working, business man, and differed from that of other hard-working people only in the quality and variety of his work. it was not an exciting life, but it was full of interest, and his work brought him into close relations with many scientific men, and with many men high in the state. his real business life commenced after he became astronomer royal, and from that time forward, during the 46 years that he remained in office, he was so entirely wrapped up in the duties of his post that the history of the observatory is the history of his life. for writing his business life there is abundant material, for he preserved all his correspondence, and the chief sources of information are as follows: (1) his autobiography. (2) his annual reports to the board of visitors. (3) his printed papers entitled "papers by g.b. airy." (4) his miscellaneous private correspondence. (5) his letters to his wife. (6) his business correspondence. (1) his autobiography, after the time that he became astronomer royal, is, as might be expected, mainly a record of the scientific work carried on at the greenwich observatory: but by no means exclusively so. about the time when he took charge of the observatory there was an immense development of astronomical enterprise: observatories were springing up in all directions, and the astronomer royal was expected to advise upon all of the british and colonial observatories. it was necessary also for him to keep in touch with the continental observatories and their work, and this he did very diligently and successfully, both by correspondence and personal intercourse with the foreign astronomers. there was also much work on important subjects more or less connected with his official duties--such as geodetical survey work, the establishment of time-balls at different places, longitude determinations, observation of eclipses, and the determination of the density of the earth. lastly, there was a great deal of time and work given to questions not very immediately connected with his office, but on which the government asked his assistance in the capacity of general scientific adviser: such were the correction of the compass in iron ships, the railway gauge commission, the commission for the restoration of the standards of length and weight, the maine boundary, lighthouses, the westminster clock, the london university, and many other questions. besides those above-mentioned there were a great many subjects which he took up out of sheer interest in the investigations. for it may fairly be said that every subject of a distinctly practical nature, which could be advanced by mathematical knowledge, had an interest for him: and his incessant industry enabled him to find time for many of them. amongst such subjects were tides and tidal observations, clockwork, and the strains in beams and bridges. a certain portion of his time was also given to lectures, generally on current astronomical questions, for he held it as his duty to popularize the science as far as lay in his power. and he attended the meetings of the royal astronomical society with great regularity, and took a very active part in the discussions and business of the society. he also did much work for the royal society, and (up to a certain date) for the british association. all of the foregoing matters are recorded pretty fully in his autobiography up to the year 1861. after that date the autobiography is given in a much more abbreviated form, and might rather be regarded as a collection of notes for his biography. his private history is given very fully for the first part of his life, but is very lightly touched upon during his residence at greenwich. a great part of the autobiography is in a somewhat disjointed state, and appears to have been formed by extracts from a number of different sources, such as official journals, official correspondence, and reports. in editing the autobiography it has been thought advisable to omit a large number of short notes relating to the routine work of the observatory, to technical and scientific correspondence, to papers communicated to various societies and official business connected with them, and to miscellaneous matters of minor importance. these in the aggregate occupied a great deal of time and attention. but, from their detached nature, they would have but little general interest. at various places will be found short memoirs and other matter by the editor. (2) all of his annual reports to the board of visitors are attached to his autobiography and were evidently intended to be read with it and to form part of it. these reports are so carefully compiled and are so copious that they form a very complete history of the greenwich observatory and of the work carried on there during the time that he was astronomer royal. the first report contained only four pages, but with the constantly increasing amount and range of work the reports constantly increased in volume till the later reports contained 21 pages. extracts from these reports relating to matters of novelty and importance, and illustrating the principles which guided him in his conduct of the observatory, have been incorporated with the autobiography. (3) the printed "papers by g.b. airy" are bound in 14 large quarto volumes. there are 518 of these papers, on a great variety of subjects: a list of them is appended to this history, as also is a list of the books that he wrote, and one or two of the papers which were separately printed. they form a very important part of his life's work, and are frequently referred to in the present history. they are almost all to be found in the transactions of societies or in newspapers, and extend over a period of 63 years (1822 to 1885). the progress made in certain branches of science during this long period can very fairly be traced by these papers. (4) his private correspondence was large, and like his other papers it was carefully arranged. no business letters of any kind are included under this head. in this correspondence letters are occasionally found either dealing with matters of importance or in some way characteristic, and these have been inserted in this biography. as already stated the autobiography left by airy is confined almost entirely to science and business, and touches very lightly on private matters or correspondence. (5) the letters to his wife are very numerous. they were written during his occasional absences from home on business or for relaxation. on these occasions he rarely let a day pass without writing to his wife, and sometimes he wrote twice on the same day. they are full of energy and interest and many extracts from them are inserted in this history. a great deal of the personal history is taken from them. (6) all correspondence in any way connected with business during the time that he was astronomer royal is to be found at the royal observatory. it is all bound and arranged in the most perfect order, and any letter throughout this time can be found with the greatest ease. it is very bulky, and much of it is, in a historical sense, very interesting. it was no doubt mainly from this correspondence that the autobiography, which so far as related to the greenwich part of it was almost entirely a business history, was compiled. the history of the early part of his life was written in great detail and contained a large quantity of family matter which was evidently not intended for publication. this part of the autobiography has been compressed. the history of the latter part of his life was not written by himself at all, and has been compiled from his journal and other sources. in both these cases, and occasionally in short paragraphs throughout the narrative, it has been found convenient to write the history in the third person. 2, the circus, greenwich. note. the syndics of the cambridge university press desire to express their thanks to messrs macmillan & co. for their courteous permission to use in this work the steel engraving of sir george biddell airy published in _nature_ on october 31, 1878. table of contents. chapter i. personal sketch of george biddell airy chapter ii. from his birth to his taking his b.a. degree at cambridge chapter iii. at trinity college, cambridge, from his taking his b.a. degree to his taking charge of the cambridge observatory as plumian professor chapter iv. at cambridge observatory, from his taking charge of the cambridge observatory to his residence at greenwich observatory as astronomer royal chapter v. at greenwich observatory, 1836-1846 chapter vi. at greenwich observatory, 1846-1856 chapter vii. at greenwich observatory, 1856-1866 chapter viii. at greenwich observatory, 1866-1876 chapter ix. at greenwich observatory, from january 1st, 1876, to his resignation of office on august 15th, 1881 chapter x. at the white house, greenwich, from his resignation of office on august 15th, 1881, to his death on january 2nd, 1892 appendix. list of printed papers by g.b. airy, and list of books written by g.b. airy index. chapter i. personal sketch of george biddell airy. the history of airy's life, and especially the history of his life's work, is given in the chapters that follow. but it is felt that the present memoir would be incomplete without a reference to those personal characteristics upon which the work of his life hinged and which can only be very faintly gathered from his autobiography. he was of medium stature and not powerfully built: as he advanced in years he stooped a good deal. his hands were large-boned and well-formed. his constitution was remarkably sound. at no period in his life does he seem to have taken the least interest in athletic sports or competitions, but he was a very active pedestrian and could endure a great deal of fatigue. he was by no means wanting in physical courage, and on various occasions, especially in boating expeditions, he ran considerable risks. in debate and controversy he had great self-reliance, and was absolutely fearless. his eye-sight was peculiar, and required correction by spectacles the lenses of which were ground to peculiar curves according to formulae which he himself investigated: with these spectacles he saw extremely well, and he commonly carried three pairs, adapted to different distances: he took great interest in the changes that took place in his eye-sight, and wrote several papers on the subject. in his later years he became somewhat deaf, but not to the extent of serious personal inconvenience. the ruling feature of his character was undoubtedly order. from the time that he went up to cambridge to the end of his life his system of order was strictly maintained. he wrote his autobiography up to date soon after he had taken his degree, and made his first will as soon as he had any money to leave. his accounts were perfectly kept by double entry throughout his life, and he valued extremely the order of book-keeping: this facility of keeping accounts was very useful to him. he seems not to have destroyed a document of any kind whatever: counterfoils of old cheque-books, notes for tradesmen, circulars, bills, and correspondence of all sorts were carefully preserved in the most complete order from the time that he went to cambridge; and a huge mass they formed. to a high appreciation of order he attributed in a great degree his command of mathematics, and sometimes spoke of mathematics as nothing more than a system of order carried to a considerable extent. in everything he was methodical and orderly, and he had the greatest dread of disorder creeping into the routine work of the observatory, even in the smallest matters. as an example, he spent a whole afternoon in writing the word "empty" on large cards, to be nailed upon a great number of empty packing boxes, because he noticed a little confusion arising from their getting mixed with other boxes containing different articles; and an assistant could not be spared for this work without withdrawing him from his appointed duties. his arrangement of the observatory correspondence was excellent and elaborate: probably no papers are more easy of reference than those arranged on his system. his strict habits of order made him insist very much upon detail in his business with others, and the rigid discipline arising out of his system of order made his rule irksome to such of his subordinates as did not conform readily to it: but the efficiency of the observatory unquestionably depended mainly upon it. as his powers failed with age the ruling passion for order assumed a greater prominence; and in his last days he seemed to be more anxious to put letters which he received into their proper place for reference than even to master their contents. his nature was eminently practical, and any subject which had a distinctly practical object, and could be advanced by mathematical investigation, possessed interest for him. and his dislike of mere theoretical problems and investigations was proportionately great. he was continually at war with some of the resident cambridge mathematicians on this subject. year after year he criticised the senate house papers and the smith's prize papers question by question very severely: and conducted an interesting and acrimonious private correspondence with professor cayley on the same subject. his great mathematical powers and his command of mathematics are sufficiently evidenced by the numerous mathematical treatises of the highest order which he published, a list of which is appended to this biography. but a very important feature of his investigations was the thoroughness of them. he was never satisfied with leaving a result as a barren mathematical expression. he would reduce it, if possible, to a practical and numerical form, at any cost of labour: and would use any approximations which would conduce to this result, rather than leave the result in an unfruitful condition. he never shirked arithmetical work: the longest and most laborious reductions had no terrors for him, and he was remarkably skilful with the various mathematical expedients for shortening and facilitating arithmetical work of a complex character. this power of handling arithmetic was of great value to him in the observatory reductions and in the observatory work generally. he regarded it as a duty to finish off his work, whatever it was, and the writer well remembers his comment on the mathematics of one of his old friends, to the effect that "he was too fond of leaving a result in the form of three complex equations with three unknown quantities." to one who had known, in some degree, of the enormous quantity of arithmetical work which he had turned out, and the unsparing manner in which he had devoted himself to it, there was something very pathetic in his discovery, towards the close of his long life, "that the figures would not add up." his energy and business capacity were remarkable. he was made for work and could not long be happy without it. whatever subject he was engaged upon, he kept his object clearly in view, and made straight for it, aiming far more at clearness and directness than at elegance of periods or symmetry of arrangement. he wrote his letters with great ease and rapidity: and having written them he very rarely had occasion to re-write them, though he often added insertions and interlineations, even in the most important official letters. without this it would have been impossible for him to have turned out the enormous quantity of correspondence that he did. he never dictated letters, and only availed himself of clerical assistance in matters of the most ordinary routine. in his excursions, as in his work, he was always energetic, and could not endure inaction. whatever there was of interest in the places that he visited he examined thoroughly and without delay, and then passed on. and he thus accomplished a great deal in a short vacation. his letters written to his wife, while he was on his excursions, are very numerous and characteristic, and afford ample proofs of his incessant energy and activity both of body and mind. they are not brilliantly written, for it was not in his nature to write for effect, and he would never give himself the trouble to study the composition of his letters, but they are straight-forward, clear, and concise, and he was never at a loss for suitable language to express his ideas. he had a wonderful capacity for enjoyment: the subjects that chiefly interested him were scenery, architecture, and antiquities, but everything novel or curious had an interest for him. he made several journeys to the continent, but by far the greater number of his excursions were made in england and scotland, and there were few parts of the country which he had not visited. he was very fond of the lake district of cumberland, and visited it very frequently, and each time that he went there the same set of views had an eternal freshness for him, and he wrote long descriptions of the scenery and effects with the same raptures as if he had seen it for the first time. many of his letters were written from playford, a village in a beautiful part of suffolk, a few miles from ipswich. here he had a small property, and generally stayed there for a short time once or twice a year. he was extremely fond of this country, and was never tired of repeating his walks by the well-known lanes and footpaths. and, as in cumberland, the suffolk country had an eternal freshness and novelty for him. wherever he went he was indefatigable in keeping up his acquaintance with his numerous friends and his letters abound in social reminiscences. his memory was singularly retentive. it was much remarked at school in his early days, and in the course of his life he had stored up in his memory an incredible quantity of poetry, ballads, and miscellaneous facts and information of all sorts, which was all constantly ready and at his service. it is almost needless to add that his memory was equally accurate and extensive in matters connected with science or business. his independence of character was no doubt due to and inseparable from his great powers. the value of his scientific work greatly depended upon his self-reliance and independence of thought. and in the heavy work of remodelling the observatory it was a very valuable quality. this same self-reliance made him in his latter years apt to draw conclusions too confidently and hastily on subjects which he had taken up more as a pastime than as work. but whatever he touched he dealt with ably and in the most fearless truthseeking manner, and left original and vigorous opinions. he had a remarkably well-balanced mind, and a simplicity of nature that appeared invulnerable. no amount of hero-worship seemed to have the least effect upon him. and from a very early time he was exposed to a great deal of it. his mind was incessantly engaged on investigations of nature, and this seems to have been with him, as has been the case with others, a preserving influence. this simplicity of character he retained throughout his life. at the same time he was sensible and shrewd in his money matters and attentive to his personal interests. and his practical good sense in the general affairs of life, combined with his calm and steady consideration of points submitted to him, made his advice very valuable. this was especially recognized by his own and his wife's relations, who consulted him on many occasions and placed the fullest confidence in his absolute sense of justice as well as in his wise counsel. he was extremely liberal in proportion to his means, and gave away money to a large extent to all who had any claim upon him. but he was not in any sense reckless, and kept a most cautious eye on his expenses. he was not indifferent to the honours which he received in the scientific world, but he does not appear to have sought them in any way, and he certainly did not trouble himself about them. his courtesy was unfailing: no amount of trouble could shake it. whether it was the secretary of the admiralty, or a servant girl wanting her fortune told: whether a begging-letter for money, or miscellaneous invitations: all had their answer in the most clear and courteous language. but he would not grant personal interviews when he could avoid it: they took up too much of his time. his head was so clear that he never seemed to want for the clearest and most direct language in expressing his meaning, and his letters are models of terseness. in all his views and opinions he was strongly liberal. at cambridge at an early date he was one of the 83 members of the senate who supported the application to permit the granting of medical degrees without requiring an expression of assent to the religious doctrines of the church of england. and in 1868 he declined to sign a petition against the abolition of religious declarations required of persons admitted to fellowships or proceeding to the degree of m.a. and he was opposed to every kind of narrowness and exclusiveness. when he was appointed to the post of astronomer royal, he stipulated that he should not be asked to vote in any political election. but all his views were in the liberal direction. he was a great reader of theology and church history, and as regarded forms of worship and the interpretation of the scriptures, he treated them with great respect, but from the point of view of a freethinking layman. in the preface to his "notes on the earlier hebrew scriptures" he says, "in regard to the general tone of these notes, i will first remark that i have nothing to say on the subject of verbal inspiration. with those who entertain that doctrine, i can have nothing in common. nor do i recognize, in the professedly historical accounts, any other inspiration which can exempt them from the severest criticism that would be applicable to so-called profane accounts, written under the same general circumstances, and in the same countries." and his treatment of the subject in the "notes" shews how entirely he took a rationalistic view of the whole question. he also strongly sided with bishop colenso in his fearless criticism of the pentateuch, though he dissented from some of his conclusions. but he was deeply imbued with the spirit of religion and reflected much upon it. his whole correspondence conveys the impression of the most sterling integrity and high-mindedness, without a trace of affectation. in no letter does there appear a shadow of wavering on matters of principle, whether in public or private matters, and he was very clear and positive in his convictions. the great secret of his long and successful official career was that he was a good servant and thoroughly understood his position. he never set himself in opposition to his masters, the admiralty. he never hesitated to ask the admiralty for what he thought right, whether in the way of money grants for various objects, or for occasional permission to give his services to scientific matters not immediately connected with the observatory. sometimes the admiralty refused his requests, and he felt this very keenly, but he was far too busy and energetic to trouble himself about such little slights, and cheerfully accepted the situation. what was refused by one administration was frequently granted by another; and in the meantime he was always ready to give his most zealous assistance in any matter that was officially brought before him. this cheerful readiness to help, combined with his great ability and punctuality in business matters, made him a very valuable servant, and speaking generally he had the confidence of the admiralty in a remarkable degree. in many of his reports to the board of visitors he speaks gratefully of the liberality of the admiralty in forwarding scientific progress and research. in matters too which are perhaps of minor importance from the high stand-point of science, but which are invaluable in the conduct of an important business office, such for example as estimates and official correspondence, he was orderly and punctual in the highest degree. and, what is by no means unimportant, he possessed an excellent official style in correspondence, combined with great clearness of expression. his entire honesty of purpose, and the high respect in which he was held both at home and abroad, gave great weight to his recommendations. with regard to his habits while he resided at the observatory, his custom was to work in his official room from 9 to about 2.30, though in summer he was frequently at work before breakfast. he then took a brisk walk, and dined at about 3.30. this early hour had been prescribed and insisted upon by his physician, dr haviland of cambridge, in whom he had great confidence. he ate heartily, though simply and moderately, and slept for about an hour after dinner. he then had tea, and from about 7 to 10 he worked in the same room with his family. he would never retire to a private room, and regarded the society of his family as highly beneficial in "taking the edge off his work." his powers of abstraction were remarkable: nothing seemed to disturb him; neither music, singing, nor miscellaneous conversation. he would then play a game or two at cards, read a few pages of a classical or historical book, and retire at 11. on sundays he attended morning service at church, and in the evening read a few prayers very carefully and impressively to his whole household. he was very hospitable, and delighted to receive his friends in a simple and natural way at his house. in this he was most admirably aided by his wife, whose grace and skill made everything pleasant to their guests. but he avoided dinner-parties as much as possible--they interfered too much with his work--and with the exception of scientific and official dinners he seldom dined away from home. his tastes were entirely domestic, and he was very happy in his family. with his natural love of work, and with the incessant calls upon him, he would soon have broken down, had it not been for his system of regular relaxation. two or three times a year he took a holiday: generally a short run of a week or ten days in the spring, a trip of a month or thereabouts in the early autumn, and about three weeks at playford in the winter. these trips were always conducted in the most active manner, either in constant motion from place to place, or in daily active excursions. this system he maintained with great regularity, and from the exceeding interest and enjoyment that he took in these trips his mind was so much refreshed and steadied that he always kept himself equal to his work. airy seems to have had a strong bent in the direction of astronomy from his youth, and it is curious to note how well furnished he was, by the time that he became astronomer royal, both with astronomy in all its branches, and with the kindred sciences so necessary for the practical working and improvement of it. at the time that he went to cambridge physical astronomy was greatly studied there and formed a most important part of the university course. he eagerly availed himself of this, and mastered the physical astronomy in the most thorough manner, as was evidenced by his papers collected in his "mathematical tracts," his investigation of the long inequality of the earth and venus, and many other works. as plumian professor he had charge of the small observatory at cambridge, where he did a great deal of the observing and reduction work himself, and became thoroughly versed in the practical working of an observatory. the result of this was immediately seen in the improved methods which he introduced at greenwich, and which were speedily imitated at other observatories. optics and the undulatory theory of light had been very favourite subjects with him, and he had written and lectured frequently upon them. in the construction of the new and powerful telescopes and other optical instruments required from time to time this knowledge was very essential, for in its instrumental equipment the greenwich observatory was entirely remodelled during his tenure of office. and in many of the matters referred to him, as for instance that of the lighthouses, a thorough knowledge of optics was most valuable. he had made a great study of the theory and construction of clocks, and this knowledge was invaluable to him at greenwich in the establishment of new and more accurate astronomical clocks, and especially in the improvement of chronometers. he had carefully studied the theory of pendulums, and had learned how to use them in his experiments in the cornish mines. this knowledge he afterwards utilized very effectively at the harton pit in comparing the density of the earth's crust with its mean density; and it was very useful to him in connection with geodetic surveys and experiments on which he was consulted. and his mechanical knowledge was useful in almost everything. the subjects (outside those required for his professional work) in which he took most interest were poetry, history, theology, antiquities, architecture, and engineering. he was well acquainted with standard english poetry, and had committed large quantities to memory, which he frequently referred to as a most valuable acquisition and an ever-present relief and comfort to his mind. history and theology he had studied as opportunity offered, and without being widely read in them he was much at home with them, and his powerful memory made the most of what he did read. antiquities and architecture were very favourite subjects with him. he had visited most of the camps and castles in the united kingdom and was never tired of tracing their connection with ancient military events: and he wrote several papers on this subject, especially those relating to the roman invasions of britain. ecclesiastical architecture he was very fond of: he had visited nearly all the cathedrals and principal churches in england, and many on the continent, and was most enthusiastic on their different styles and merits: his letters abound in critical remarks on them. he was extremely well versed in mechanics, and in the principles and theory of construction, and took the greatest interest in large engineering works. this led to much communication with stephenson, brunel, and other engineers, who consulted him freely on the subject of great works on which they were engaged: in particular he rendered much assistance in connection with the construction of the britannia bridge over the menai straits. there were various other subjects which he read with much interest (geology in particular), but he made no study of natural history, and knew very little about it beyond detached facts. his industry was untiring, and in going over his books one by one it was very noticeable how large a number of them were feathered with his paper "marks," shewing how carefully he had read them and referred to them. his nature was essentially cheerful, and literature of a witty and humourous character had a great charm for him. he was very fond of music and knew a great number of songs; and he was well acquainted with the theory of music: but he was no performer. he did not sketch freehand but made excellent drawings with his camera lucida. at the time when he took his degree (1823) and for many years afterwards there was very great activity of scientific investigation and astronomical enterprise in england. and, as in the times of flamsteed and halley, the earnest zeal of men of science occasionally led to much controversy and bitterness amongst them. airy was by no means exempt from such controversies. he was a man of keen sensitiveness, though it was combined with great steadiness of temper, and he never hesitated to attack theories and methods that he considered to be scientifically wrong. this led to differences with ivory, challis, south, cayley, archibald smith, and others; but however much he might differ from them he was always personally courteous, and the disputes generally went no farther than as regarded the special matter in question. almost all these controversial discussions were carried on openly, and were published in the athenaeum, the philosophical magazine, or elsewhere; for he printed nearly everything that he wrote, and was very careful in the selection of the most suitable channels for publication. he regarded it as a duty to popularize as much as possible the work done at the observatory, and to take the public into his confidence. and this he effected by articles communicated to newspapers, lectures, numerous papers written for scientific societies, reports, debates, and critiques. his strong constitution and his regular habits, both of work and exercise, are sufficient explanation of the good health which in general he enjoyed. not but what he had sharp touches of illness from time to time. at one period he suffered a good deal from an attack of eczema, and at another from a varicose vein in his leg, and he was occasionally troubled with severe colds. but he bore these ailments with great patience and threw them off in course of time. he was happy in his marriage and in his family, and such troubles and distresses as were inevitable he accepted calmly and quietly. in his death, as in his life, he was fortunate: he had no long or painful illness, and he was spared the calamity of aberration of intellect, the saddest of all visitations. chapter ii. from his birth to his taking his b.a. degree at cambridge. from july 27th 1801 to january 18th 1823. george biddell airy was born at alnwick in northumberland on july 27th 1801. his father was william airy of luddington in lincolnshire, the descendant of a long line of airys who have been traced back with a very high degree of probability to a family of that name which was settled at kentmere in westmorland in the 14th century. a branch of this family migrated to pontefract in yorkshire, where they seem to have prospered for many years, but they were involved in the consequences of the civil wars, and one member of the family retired to ousefleet in yorkshire. his grandson removed to luddington in lincolnshire, where his descendants for several generations pursued the calling of small farmers. george biddell airy's mother, ann airy, was the daughter of george biddell, a well-to-do farmer in suffolk. william airy, the father of george biddell airy, was a man of great activity and strength, and of prudent and steady character. when a young man he became foreman on a farm in the neighbourhood of luddington, and laid by his earnings in summer in order to educate himself in winter. for a person in his rank, his education was unusually good, in matters of science and in english literature. but at the age of 24 he grew tired of country labour, and obtained a post in the excise. after serving in various collections he was appointed collector of the northumberland collection on the 15th august 1800, and during his service there his eldest son george biddell airy was born. the time over which his service as officer and supervisor extended was that in which smuggling rose to a very high pitch, and in which the position of excise officer was sometimes dangerous. he was remarkable for his activity and boldness in contests with smugglers, and made many seizures. ann airy, the mother of george biddell airy, was a woman of great natural abilities both speculative and practical, kind as a neighbour and as head of a family, and was deeply loved and respected. the family consisted of george biddell, elizabeth, william, and arthur who died young. william airy was appointed to hereford collection on 22nd october 1802, and removed thither shortly after. he stayed at hereford till he was appointed to essex collection on 28th february 1810, and during this time george biddell was educated at elementary schools in writing, arithmetic, and a little latin. he records of himself that he was not a favourite with the schoolboys, for he had very little animal vivacity and seldom joined in active play with his schoolfellows. but in the proceedings of the school he was successful, and was a favourite with his master. on the appointment of william airy to essex collection, the family removed to colchester on april 5th 1810. here george biddell was first sent to a large school in sir isaac's walk, then kept by mr byatt walker, and was soon noted for his correctness in orthography, geography, and arithmetic. he evidently made rapid progress, for on one occasion mr walker said openly in the schoolroom how remarkable it was that a boy 10 years old should be the first in the school. at this school he stayed till the end of 1813 and thoroughly learned arithmetic (from walkingame's book), book-keeping by double entry (on which knowledge throughout his life he set a special value), the use of the sliding rule (which knowledge also was specially useful to him in after life), mensuration and algebra (from bonnycastle's books). he also studied grammar in all its branches, and geography, and acquired some knowledge of english literature, beginning with that admirable book the speaker, but it does not appear that latin and greek were attended to at this school. he records that at this time he learned an infinity of snatches of songs, small romances, &c., which his powerful memory retained most accurately throughout his life. he was no hand at active play: but was notorious for his skill in constructing guns for shooting peas and arrows, and other mechanical contrivances. at home he relates that he picked up a wonderful quantity of learning from his father's books. he read and remembered much poetry from such standard authors as milton, pope, gay, gray, swift, &c., which was destined to prove in after life an invaluable relaxation for his mind. but he also studied deeply an excellent cyclopaedia called a dictionary of arts and sciences in three volumes folio, and learned from it much about ship-building, navigation, fortification, and many other subjects. during this period his valuable friendship with his uncle arthur biddell commenced. arthur biddell was a prosperous farmer and valuer at playford near ipswich. he was a well-informed and able man, of powerful and original mind, extremely kind and good-natured, and greatly respected throughout the county. in the autobiography of george biddell airy he states as follows: "i do not remember precisely when it was that i first visited my uncle arthur biddell. i think it was in a winter: certainly as early as the winter of 1812--13. here i found a friend whose society i could enjoy, and i entirely appreciated and enjoyed the practical, mechanical, and at the same time speculative and enquiring talents of arthur biddell. he had a library which, for a person in middle life, may be called excellent, and his historical and antiquarian knowledge was not small. after spending one winter holiday with him, it easily came to pass that i spent the next summer holiday with him: and at the next winter holiday, finding that there was no precise arrangement for my movements, i secretly wrote him a letter begging him to come with a gig to fetch me home with him: he complied with my request, giving no hint to my father or mother of my letter: and from that time, one-third of every year was regularly spent with him till i went to college. how great was the influence of this on my character and education i cannot tell. it was with him that i became acquainted with the messrs ransome, w. cubitt the civil engineer (afterwards sir w. cubitt), bernard barton, thomas clarkson (the slave-trade abolitionist), and other persons whose acquaintance i have valued highly. it was also with him that i became acquainted with the works of the best modern poets, scott, byron, campbell, hogg, and others: as also with the waverley novels and other works of merit." in 1813 william airy lost his appointment of collector of excise and was in consequence very much straitened in his circumstances. but there was no relaxation in the education of his children, and at the beginning of 1814 george biddell was sent to the endowed grammar school at colchester, then kept by the rev. e. crosse, and remained there till the summer of 1819, when he went to college. the autobiography proceeds as follows: "i became here a respectable scholar in latin and greek, to the extent of accurate translation, and composition of prose latin: in regard to latin verses i was i think more defective than most scholars who take the same pains, but i am not much ashamed of this, for i entirely despise the system of instruction in verse composition. "my father on some occasion had to go to london and brought back for me a pair of 12-inch globes. they were invaluable to me. the first stars which i learnt from the celestial globe were alpha lyrae, alpha aquilae, alpha cygni: and to this time i involuntarily regard these stars as the birth-stars of my astronomical knowledge. having somewhere seen a description of a gunter's quadrant, i perceived that i could construct one by means of the globe: my father procured for me a board of the proper shape with paper pasted on it, and on this i traced the lines of the quadrant. "my command of geometry was tolerably complete, and one way in which i frequently amused myself was by making paper models (most carefully drawn in outline) which were buttoned together without any cement or sewing. thus i made models, not only of regular solids, regularly irregular solids, cones cut in all directions so as to shew the conic sections, and the like, but also of six-gun batteries, intrenchments and fortresses of various kinds &c. "from various books i had learnt the construction of the steam-engine: the older forms from the dictionary of arts and sciences; newer forms from modern books. the newest form however (with the sliding steam valve) i learnt from a 6-horse engine at bawtrey's brewery (in which mr keeling the father of my schoolfellow had acquired a partnership). i frequently went to look at this engine, and on one occasion had the extreme felicity of examining some of its parts when it was opened for repair. "in the mean time my education was advancing at playford. the first record, i believe, which i have of my attention to mechanics there is the plan of a threshing-machine which i drew. but i was acquiring valuable information of all kinds from the encyclopaedia londinensis, a work which without being high in any respect is one of the most generally useful that i have seen. but i well remember one of the most important steps that i ever made. i had tried experiments with the object-glass of an opera-glass and was greatly astonished at the appearance of the images of objects seen through the glass under different conditions. by these things my thoughts were turned to accurate optics, and i read with care rutherford's lectures, which my uncle possessed. the acquisition of an accurate knowledge of the effect of optical constructions was one of the most charming attainments that i ever reached. long before i went to college i understood the action of the lenses of a telescope better than most opticians. i also read with great zeal nicholson's dictionary of chemistry, and occasionally made chemical experiments of an inexpensive kind: indeed i grew so fond of this subject that there was some thought of apprenticing me to a chemist. i also attended to surveying and made a tolerable survey and map of my uncle's farm. "at school i was going on successfully, and distinguished myself particularly by my memory. it was the custom for each boy once a week to repeat a number of lines of latin or greek poetry, the number depending very much on his own choice. i determined on repeating 100 every week, and i never once fell below that number and was sometimes much above it. it was no distress to me, and great enjoyment. at michaelmas 1816 i repeated 2394 lines, probably without missing a word. i do not think that i was a favourite with mr crosse, but he certainly had a high opinion of my powers and expressed this to my father. my father entertained the idea of sending me to college, which mr crosse recommended: but he heard from some college man that the expense would be _â£200_ a year, and he laid aside all thoughts of it. "the farm of playford hall was in 1813 or 1814 hired by thomas clarkson, the slave-trade abolitionist. my uncle transacted much business for him (as a neighbour and friend) in the management of the farm &c. for a time, and they became very intimate. my uncle begged him to examine me in classical knowledge, and he did so, i think, twice. he also gave some better information about the probable expenses &c. at college. the result was a strong recommendation by my uncle or through my uncle that i should be sent to cambridge, and this was adopted by my father. i think it likely that this was in 1816. "in december 1816, dealtry's fluxions was bought for me, and i read it and understood it well. i borrowed hutton's course of mathematics of old mr ransome, who had come to reside at greenstead near colchester, and read a good deal of it. "about ladyday 1817 i began to read mathematics with mr rogers (formerly, i think, a fellow of sidney college, and an indifferent mathematician of the cambridge school), who had succeeded a mr tweed as assistant to mr crosse in the school. i went to his house twice a week, on holiday afternoons. i do not remember how long i received lessons from him, but i think to june, 1818. this course was extremely valuable to me, not on account of mr rogers's abilities (for i understood many things better than he did) but for its training me both in cambridge subjects and in the cambridge accurate methods of treating them. i went through euclid (as far as usually read), wood's algebra, wood's mechanics, vince's hydrostatics, wood's optics, trigonometry (in a geometrical treatise and also in woodhouse's algebraical form), fluxions to a good extent, newton's principia to the end of the 9th section. this was a large quantity, but i read it accurately and understood it perfectly, and could write out any one of the propositions which i had read in the most exact form. my connexion with mr rogers was terminated by _his_ giving me notice that he could not undertake to receive me any longer: in fact i was too much for him. i generally read these books in a garret in our house in george lane, which was indefinitely appropriated to my brother and myself. i find that i copied out vince's conic sections in february, 1819. the first book that i copied was the small geometrical treatise on trigonometry, in may, 1817: to this i was urged by old mr ransome, upon my complaining that i could not purchase the book: and it was no bad lesson of independence to me." during the same period 1817-1819 he was occupied at school on translations into blank verse from the aeneid and iliad, and read through the whole of sophocles very carefully. the classical knowledge which he thus gained at school and subsequently at cambridge was sound, and he took great pleasure in it: throughout his life he made a practice of keeping one or other of the classical authors at hand for occasional relaxation. he terminated his schooling in june 1819. shortly afterwards his father left colchester and went to reside at bury st edmund's. the autobiography proceeds as follows: "mr clarkson was at one time inclined to recommend me to go to st peter's college (which had been much enriched by a bequest from a mr gisborne). but on giving some account of me to his friend mr james d. hustler, tutor of trinity college, mr hustler urged upon him that i was exactly the proper sort of person to go to trinity college. and thus it was settled (mainly by mr clarkson) that i should be entered at trinity college. i think that i was sent for purposely from colchester to playford, and on march 6th, 1819, i rode in company with mr clarkson from playford to sproughton near ipswich to be examined by the rev. mr rogers, incumbent of sproughton, an old m.a. of trinity college; and was examined, and my certificate duly sent to mr hustler; and i was entered on mr hustler's side as sizar of trinity college. "in the summer of 1819 i spent some time at playford. on july 27th, 1819 (my birthday, 18 years old), mr clarkson invited me to dinner, to meet mr charles musgrave, fellow of trinity college, who was residing for a short time at grundisburgh, taking the church duty there for dr ramsden, the rector. it was arranged that i should go to grundisburgh the next day (i think) to be examined in mathematics by mr musgrave. i went accordingly, and mr musgrave set before me a paper of questions in geometry, algebra, mechanics, optics, &c. ending with the first proposition of the principia. i knew nothing more about my answers at the time; but i found long after that they excited so much admiration that they were transmitted to cambridge (i forget whether to mr musgrave's brother, a fellow of trinity college and afterwards archbishop of york, or to mr peacock, afterwards dean of ely) and were long preserved. "the list of the classical subjects for the first year in trinity college was transmitted to me, as usual, by mr hustler. they were--the hippolytus of euripides, the 3rd book of thucydides, and the 2nd philippic of cicero. these i read carefully and noted before going up. mr hustler's family lived in bury; and i called on him and saw him in october, introduced by mr clarkson. on the morning of october 18th, 1819, i went on the top of the coach to cambridge, knowing nobody there but mr hustler, but having letters of introduction from mr charles musgrave to professor sedgwick, mr thomas musgrave, and mr george peacock, all fellows of trinity college. "i was set down at the hoop, saw trinity college for the first time, found mr hustler, was conducted by his servant to the robe-maker's, where i was invested in the cap and blue gown, and after some further waiting was installed into lodgings in bridge street. at 4 o'clock i went to the college hall and was introduced by mr hustler to several undergraduates, generally clever men, and in the evening i attended chapel in my surplice (it being st luke's day) and witnessed that splendid service of which the occasional exhibition well befits the place. "as soon as possible, i called on mr peacock, mr musgrave, and professor sedgwick. by all i was received with great kindness: my examination papers had been sent to them, and a considerable reputation preceded me. mr peacock at once desired that i would not consider mr c. musgrave's letter as an ordinary introduction, but that i would refer to him on all occasions. and i did so for several years, and always received from him the greatest assistance that he could give. i think that i did not become acquainted with mr whewell till the next term, when i met him at a breakfast party at mr peacock's. mr peacock at once warned me to arrange for taking regular exercise, and prescribed a walk of two hours every day before dinner: a rule to which i attended regularly, and to which i ascribe the continuance of good general health. "i shewed mr peacock a manuscript book which contained a number of original propositions which i had investigated. these much increased my reputation (i really had sense enough to set no particular value on it) and i was soon known by sight to almost everybody in the university. a ridiculous little circumstance aided in this. the former rule of the university (strictly enforced) had been that all students should wear drab knee-breeches: and i, at mr clarkson's recommendation, was so fitted up. the struggle between the old dress and the trowsers customary in society was still going on but almost terminated, and i was one of the very few freshmen who retained the old habiliments. this made me in some measure distinguishable: however at the end of my first three terms i laid these aside. "the college lectures began on oct. 22: mr evans at 9 on the hippolytus, and mr peacock at 10 on euclid (these being the assistant tutors on mr hustler's side): and then i felt myself established. "i wrote in a day or two to my uncle arthur biddell, and i received from him a letter of the utmost kindness. he entered gravely on the consideration of my prospects, my wants, &c.: and offered at all times to furnish me with money, which he thought my father's parsimonious habits might make him unwilling to do. i never had occasion to avail myself of this offer: but it was made in a way which in no small degree strengthened the kindly feelings that had long existed between us. "i carefully attended the lectures, taking notes as appeared necessary. in mathematics there were geometrical problems, algebra, trigonometry (which latter subjects the lectures did not reach till the terms of 1820). mr peacock gave me a copy of lacroix's differential calculus as translated by himself and herschel and babbage, and also a copy of their examples. at this time, the use of differential calculus was just prevailing over that of fluxions (which i had learnt). i betook myself to it with great industry. i also made myself master of the theories of rectangular coordinates and some of the differential processes applying to them, which only a few of the best of the university mathematicians then wholly possessed. in classical subjects i read the latin (seneca's) and english hippolytus, racine's phã¨dre (which my sister translated for me), and all other books to which i was referred, aristotle, longinus, horace, bentley, dawes &c., made verse translations of the greek hippolytus, and was constantly on the watch to read what might be advantageous. "early in december mr hustler sent for me to say that one of the company of fishmongers, mr r. sharp, had given to mr john h. smyth, m.p. for norwich, the presentation to a small exhibition of _â£20_ a year, which mr smyth had placed in mr hustler's hands, and which mr hustler immediately conferred on me. this was my first step towards pecuniary independence. i retained this exhibition till i became a fellow of the college. "i stayed at cambridge during part of the winter vacation, and to avoid expense i quitted my lodgings and went for a time into somebody's rooms in the bishop's hostel. (it is customary for the tutors to place students in rooms when their right owners are absent.) i took with me thucydides and all relating to it, and read the book, upon which the next term's lectures were to be founded, very carefully. the latter part of the vacation i spent at bury, where i began with the assistance of my sister to pick up a little french: as i perceived that it was absolutely necessary for enabling me to read modern mathematics. "during a part of the time i employed myself in writing out a paper on the geometrical interpretation of the algebraical expression sqrt(-1). i think that the original suggestion of perpendicular line came from some book (i do not remember clearly), and i worked it out in several instances pretty well, especially in de moivre's theorem. i had spoken of it in the preceding term to mr peacock and he encouraged me to work it out. the date at the end is 1820, january 21. when some time afterwards i spoke of it to mr hustler, he disapproved of my employing my time on such speculations. about the last day of january i returned to cambridge, taking up my abode in my former lodgings. i shewed my paper on sqrt(-1) to mr peacock, who was much pleased with it and shewed it to mr whewell and others. "on february 1 i commenced two excellent customs. the first was that i always had upon my table a quire of large-sized scribbling-paper sewn together: and upon this paper everything was entered: translations into latin and out of greek, mathematical problems, memoranda of every kind (the latter transferred when necessary to the subsequent pages), and generally with the date of the day. this is a most valuable custom. the other was this: as i perceived that to write latin prose well would be useful to me, i wrote a translation of english into latin every day. however much pressed i might be with other business, i endeavoured to write at least three or four words, but if possible i wrote a good many sentences. "i may fix upon this as the time when my daily habits were settled in the form in which they continued for several years. i rose in time for the chapel service at 7. it was the college regulation that every student should attend chapel four mornings and four evenings (sunday being one of each) in every week: and in this i never failed. after chapel service i came to my lodgings and breakfasted. at 9 i went to college lectures, which lasted to 11. most of my contemporaries, being intended for the church, attended also divinity lectures: but i never did. i then returned, put my lecture notes in order, wrote my piece of latin prose, and then employed myself on the subject which i was reading for the time: usually taking mathematics at this hour. at 2 or a little sooner i went out for a long walk, usually 4 or 5 miles into the country: sometimes if i found companions i rowed on the cam (a practice acquired rather later). a little before 4 i returned, and at 4 went to college hall. after dinner i lounged till evening chapel time, 1/2 past 5, and returning about 6 i then had tea. then i read quietly, usually a classical subject, till 11; and i never, even in the times when i might seem most severely pressed, sat up later. "from this time to the close of the annual examination (beginning of june) i remained at cambridge, stopping there through the easter vacation. the subjects of the mathematical lectures were ordinary algebra and trigonometry: but mr peacock always had some private problems of a higher class for me, and saw me i believe every day. the subjects of the classical lectures were, the termination of hippolytus, the book of thucydides and the oration of cicero. in mathematics i read whewell's mechanics, then just published (the first innovation made in the cambridge system of physical sciences for many years): and i find in my scribbling-paper notes, integrals, central forces, finite differences, steam-engine constructions and powers, plans of bridges, spherical trigonometry, optical calculations relating to the achromatism of eye-pieces and achromatic object-glasses with lenses separated, mechanical problems, transit of venus, various problems in geometrical astronomy (i think it was at this time that mr peacock had given me a copy of woodhouse's astronomy 1st edition), the rainbow, plans for anemometer and for a wind-pumping machine, clearing lunars, &c., with a great number of geometrical problems. i remark that my ideas on the differential calculus had not acquired on some important points the severe accuracy which they acquired in a few months. in classics i read the persae of aeschylus, greek and roman history very much (mitford, hooke, ferguson) and the books of thucydides introductory to that of the lecture subject (the 3rd): and attended to chronology. on the scribbling-paper are verse-translations from euripides, careful prose-translations from thucydides, maps, notes on points of grammar &c. i have also little ms. books with abundant notes on all these subjects: i usually made a little book when i pursued any subject in a regular way. "on may 1st mr dobree, the head lecturer, sent for me to say that he appointed me head-lecturer's sizar for the next year. the stipend of this office was _â£10_, a sum upon which i set considerable value in my anxiety for pecuniary independence: but it was also gratifying to me as shewing the way in which i was regarded by the college authorities. "on wednesday, may 24th, 1820, the examination began. i was anxious about the result of the examination, but only in such a degree as to make my conduct perfectly steady and calm, and to prevent me from attempting any extraordinary exertion. "when the classes were published the first class of the freshman's year (alphabetically arranged, as is the custom) stood thus: airy, boileau, childers, drinkwater, field, iliff, malkin, myers, romilly, strutt, tate, winning. it was soon known however that i was first of the class. it was generally expected (and certainly by me) that, considering how great a preponderance the classics were understood, in the known system of the college, to have in determining the order of merit, field would be first. however the number of marks which field obtained was about 1700, and that which i obtained about 1900. no other competitor, i believe, was near us."--in a letter to airy from his college tutor, mr j. d. hustler, there is the following passage: "it is a matter of extreme satisfaction to me that in the late examination you stood not only in the first class but first of the first. i trust that your future exertions and success will be commensurate with this honourable beginning." "of the men whom i have named, drinkwater (bethune) was afterwards legal member of the supreme court of india, field was afterwards rector of reepham, romilly (afterwards lord romilly) became solicitor-general, strutt (afterwards lord belper) became m.p. for derby and first commissioner of railways, tate was afterwards master of richmond endowed school, childers was the father of childers who was subsequently first lord of the admiralty. "i returned to bury immediately. while there, some students (some of them men about to take their b.a. degree at the next january) applied to me to take them as pupils, but i declined. this year of my life enabled me to understand how i stood among men. i returned to cambridge about july 11th. as a general rule, undergraduates are not allowed to reside in the university during the long vacation. i believe that before i left, after the examination, i had made out that i should be permitted to reside: or i wrote to mr hustler. i applied to mr hustler to be lodged in rooms in college: and was put, first into rooms in bishop's hostel, and subsequently into rooms in the great court. "the first affair that i had in college was one of disappointment by no means deserving the importance which it assumed in my thoughts. i had been entered a sizar, but as the list of foundation sizars was full, my dinners in hall were paid for. some vacancies had arisen: and as these were to be filled up in order of merit, i expected one: and in my desire for pecuniary independence i wished for it very earnestly. however, as in theory all of the first class were equal, and as there were some sizars in it senior in entrance to me, they obtained places first: and i was not actually appointed till after the next scholarship examination (easter 1821). however a special arrangement was made, allowing me (i forget whether others) to sit at the foundation-sizars' table whenever any of the number was absent: and in consequence i received practically nearly the full benefits. "mr peacock, who was going out for the vacation, allowed me access to his books. i had also (by the assistance of various fellows, who all treated me with great kindness, almost to a degree of respect) command of the university library and trinity library: and spent this long vacation, like several others, very happily indeed. "the only non-mathematical subjects of the next examination were the gospel of st luke, paley's evidences, and paley's moral and political philosophy. thus my time was left more free to mathematics and to general classics than last year. i now began a custom which i maintained for some years. generally i read mathematics in the morning, and classics for lectures in the afternoon: but invariably i began at 10 o'clock in the evening to read with the utmost severity some standard classics (unconnected with the lectures) and at 11 precisely i left off and went to bed. i continued my daily translations into latin prose as before. "on august 24th, 1820, rosser, a man of my own year, engaged me as private tutor, paying at the usual rate (_â£14_ for a part of the vacation, and _â£14_ for a term): and immediately afterwards his friend bedingfield did the same. this occupied two hours every day, and i felt that i was now completely earning my own living. i never received a penny from my friends after this time. "i find on my scribbling-paper various words which shew that in reading poisson i was struggling with french words. there are also finite differences and their calculus, figure of the earth (force to the center), various attractions (some evidently referring to maclaurin's), integrals, conic sections, kepler's problem, analytical geometry, d'alembert's theorem, spherical aberration, rotations round three axes (apparently i had been reading euler), floating bodies, evolute of ellipse, newton's treatment of the moon's variation. i attempted to extract something from vince's astronomy on the physical explanation of precession: but in despair of understanding it, and having made out an explanation for myself by the motion round three axes, i put together a little treatise (sept. 10, 1820) which with some corrections and additions was afterwards printed in my mathematical tracts. on sept. 14th i bought woodhouse's physical astronomy, and this was quite an epoch in my mathematical knowledge. first, i was compelled by the process of "changing the independent variable" to examine severely the logic of the differential calculus. secondly, i was now able to enter on the theory of perturbations, which for several years had been the desired land to me. "at the fellowship election of oct. 1st, sydney walker (among other persons) was elected fellow. he then quitted the rooms in which he had lived (almost the worst in the college), and i immediately took them. they suited me well and i lived very happily in them till i was elected scholar. they are small rooms above the middle staircase on the south side of neville's court. (mr peacock's rooms were on the same staircase.) i had access to the leads on the roof of the building from one of my windows. this was before the new court was built: my best window looked upon the garden of the college butler. "i had brought to cambridge the telescope which i had made at colchester, and about this time i had a stand made by a carpenter at cambridge: and i find repeated observations of jupiter and saturn made in this october term. "other mathematical subjects on my scribbling-paper are: geometrical astronomy, barometers (for elevations), maclaurin's figure of the earth, lagrange's theorem, integrals, differential equations of the second order, particular solutions. in general mathematics i had much discussion with atkinson (who was senior wrangler, january 1821), and in physics with rosser, who was a friend of sir richard phillips, a vain objector to gravitation. in classics i read aeschylus and herodotus. "on october 5th i received notice from the head lecturer to declaim in english with winning. (this exercise consists in preparing a controversial essay, learning it by heart, and speaking it in chapel after the thursday evening's service.) on october 6th we agreed on the subject, "is natural difference to be ascribed to moral or to physical causes?" i taking the latter side. i spoke the declamation (reciting it without missing a word) on october 25th. on october 26th i received notice of latin declamation with myers: subject agreed on, "utrum civitati plus utilitatis an incommodi afferant leges quae ad vitas privatorum hominum ordinandas pertinent"; i took the former. the declamation was recited on november 11, when a curious circumstance occurred. my declamation was rather long: it was the first saturday of the term on which a declamation had been spoken: and it was the day on which arrived the news of the withdrawal of the bill of pains and penalties against queen caroline. (this trial had been going on through the summer, but i knew little about it.) in consequence the impatience of the undergraduates was very great, and there was such an uproar of coughing &c. in the chapel as probably was never known. the master (dr wordsworth, appointed in the beginning of the summer on the death of dr mansell, and to whom i had been indirectly introduced by mrs clarkson) and tutors and deans tried in vain to stop the hubbub. however i went on steadily to the end, not at all frightened. on the monday the master sent for me to make a sort of apology in the name of the authorities, and letters to the tutors were read at the lectures, and on the whole the transaction was nowise disagreeable to me. "on the commemoration day, december 15th, i received my prize (mitford's greece) as first-class man, after dinner in the college hall. after a short vacation spent at bury and playford i returned to cambridge, walking from bury on jan. 22nd, 1821. during the next term i find in mathematics partial differential equations, tides, sound, calculus of variations, composition of rotary motions, motion in resisting medium, lhuillier's theorem, brightness of an object as seen through a medium with any possible law of refraction (a good investigation), star-reductions, numerical calculations connected with them, equilibrium of chain under centripetal force (geometrically treated, as an improvement upon whewell's algebraical method), investigation of the magnitude of attractive forces of glass, &c., required to produce refraction. i forget about mathematical lectures; but i have an impression that i regularly attended mr peacock's lectures, and that he always set me some private problems. "i attended mr evans's lectures on st luke: and i find many notes about the history of the jews, cerinthus and various heresies, paley's moral philosophy, paley's evidences, and biblical maps: also speculations about ancient pronunciations. "for a week or more before the annual examination i was perfectly lazy. the classes of my year (junior sophs) were not published till june 11. it was soon known that i was first with 2000 marks, the next being drinkwater with 1200 marks. after a short holiday at bury and playford i returned to cambridge on july 18th, 1821. my daily life went on as usual. i find that in writing latin i began cicero de senectute (retranslating melmoth's translation, and comparing). some time in the long vacation the names of the prizemen for declamations were published: i was disappointed that not one, english or latin, was assigned to me: but it was foolish, for my declamations were rather trumpery. "my former pupil, rosser, came again on august 14th. on august 29th dr blomfield (afterwards bishop of london) called, to engage me as tutor to his brother george beecher blomfield, and he commenced attendance on sept. 1st. with these two pupils i finished at the end of the long vacation: for the next three terms i had one pupil, gibson, a newcastle man, recommended by mr peacock, i believe, as a personal friend (mr peacock being of durham). "the only classical subject appointed for the next examination was the 5th, 6th and 7th books of the odyssey: the mathematical subjects all the applied mathematics and newton. there was to be however the scholarship examination (sizars being allowed to sit for scholarships only in their 3rd year: and the scholarship being a kind of little fellowship necessary to qualify for being a candidate for the real fellowship). "when the october term began mr hustler, who usually gave lectures in mathematics to his third-year pupils, said to me that it was not worth my while to attend his lectures, and he or mr peacock suggested that drinkwater, myers, and i should attend the questionists' examinations. the questionists are those who are to take the degree of b.a. in the next january: and it was customary, not to give them lectures, but three times a week to examine them by setting mathematical questions, as the best method of preparing for the b.a. examination. accordingly it was arranged that we should attend the said examinations: but when we went the questionists of that year refused to attend. they were reported to be a weak year, and we to be a strong one: and they were disposed to take offence at us on any occasion. from some of the scholars of our year who sat at table with scholars of that year i heard that they distinguished us as 'the impudent year,' 'the annus mirabilis' &c. on this occasion they pretended to believe that the plan of our attendance at the questionists' examinations had been suggested by an undergraduate, and no explanation was of the least use. so the tutors agreed not to press the matter on them: and instead of it, drinkwater, myers, and i went three times a week to mr peacock's rooms, and he set us questions. i think that this system was also continued during the next two terms (ending in june 1822) or part of them, but i am not certain. "in august 1821 i copied out a m.s. on optics, i think from mr whewell: on august 24th one on the figure of the earth and tides; and at some other time one on the motion of a body round two centers of force; both from mr whewell. on my scribbling paper i find--a problem on the vibrations of a gig as depending on the horse's step (like that of a pendulum whose support is disturbed), maclaurin's attractions, effect of separating the lenses of an achromatic object-glass (suggested by my old telescope), barlow's theory of numbers, and division of the circle into 17 parts, partial differentials, theory of eye-pieces, epicycloids, figure of the earth, time of body in arc of parabola, problem of sound, tides, refraction of lens, including thickness, &c., ivory's paper on equations, achromatism of microscope, capillary attraction, motions of fluids, euler's principal axes, spherical pendulum, equation bâ²(dâ²y/dxâ²)=(dâ²y/dtâ²), barometer, lunar theory well worked out, ordinary differential equations, calculus of variations, interpolations like laplace's for comets, kepler's theorem. in september i had my old telescope mounted on a short tripod stand, and made experiments on its adjustments. i was possessed of white's ephemeris, and i find observations of jupiter and saturn in october. i planned an engine for describing ellipses by the polar equation a/(1 + e cos theta) and tried to make a micrometer with silk threads converging to a point. mr cubitt called on oct. 4 and nov. 1; he was engaged in erecting a treadmill at cambridge gaol, and had some thoughts of sending plans for the cambridge observatory, the erection of which was then proposed. on nov. 19 i find that i had received from cubitt a nautical almanac, the first that i had. on dec. 11 i made some experiments with drinkwater: i think it was whirling a glass containing oil on water. in classics i was chiefly engaged upon thucydides and homer. on october 6th i had a letter from charles musgrave, introducing challis, who succeeded me in the cambridge observatory in 1836. "at this time my poor afflicted father was suffering much from a severe form of rheumatism or pain in the legs which sometimes prevented him from going to bed for weeks together. "on the commemoration day, dec. 18th, i received my prize as first-class man in hall again. the next day i walked to bury, and passed the winter vacation there and at playford. "i returned to cambridge on jan. 24th, 1822. on feb. 12th i kept my first act, with great compliments from the moderator, and with a most unusually large attendance of auditors. these disputations on mathematics, in latin, are now discontinued. on march 20th i kept a first opponency against sandys. about this time i received buckle, a trinity man of my own year, who was generally supposed to come next after drinkwater, as pupil. on my sheets i find integrals and differential equations of every kind, astronomical corrections (of which i prepared a book), chances, englefield's comets, investigation of the brightness within a rainbow, proof of clairaut's theorem in one case, metacentres, change of independent variable applied to a complicated case, generating functions, principal axes. on apr. 8th i intended to write an account of my eye: i was then tormented with a double image, i suppose from some disease of the stomach: and on may 28th i find by a drawing of the appearance of a lamp that the disease of my eye continued. "on feb. 11th i gave mr peacock a paper on the alteration of the focal length of a telescope as directed with or against the earth's orbital motion (on the theory of emissions) which was written out for reading to the cambridge philosophical society on feb. 24th and 25th. [this society i think was then about a year old.] on feb. 1 my ms. on precession, solar inequality, and nutation, was made complete. "the important examination for scholarships was now approaching. as i have said, this one opportunity only was given to sizars (pensioners having always two opportunities and sometimes three), and it is necessary to be a scholar in order to be competent to be a candidate for a fellowship. on apr. 10th i addressed my formal latin letter to the seniors. there were 13 vacancies and 37 candidates. the election took place on apr. 18th, 1822. i was by much the first (which i hardly expected) and was complimented by the master and others. wrote the formal letter of thanks as usual. i was now entitled to claim better rooms, and i took the rooms on the ground floor on the east side of the queen's gate of the great court. even now i think of my quiet residence in the little rooms above the staircase in neville's court with great pleasure. i took possession of my new rooms on may 27th. "the annual examination began on may 30th. the classes were published on june 5th, when my name was separated from the rest by two lines. it was understood that the second man was drinkwater, and that my number of marks was very nearly double of his. having at this time been disappointed of a proposed walking excursion into derbyshire with a college friend, who failed me at the last moment, i walked to bury and spent a short holiday there and at playford. "i returned to cambridge on july 12th, 1822. i was steadily busy during this long vacation, but by no means oppressively so: indeed my time passed very happily. the scholars' table is the only one in college at which the regular possessors of the table are sure never to see a stranger, and thus a sort of family intimacy grows up among the scholars. moreover the scholars feel themselves to be a privileged class 'on the foundation,' and this feeling gives them a sort of conceited happiness. it was the duty of scholars by turns to read grace after the fellows' dinner and supper, and at this time (1848) i know it by heart. they also read the lessons in chapel on week days: but as there was no daily chapel-service during the summer vacation, i had not much of this. in the intimacy of which i speak i became much acquainted with drinkwater, buckle, rothman, and sutcliffe: and we formed a knot at the table (first the undergraduate scholars' table, and afterwards the bachelor scholars' table) for several years. during this vacation i had for pupils buckle and gibson. "i wrote my daily latin as usual, beginning with the retranslation of cicero's epistles, but i interrupted it from sept. 27th to feb. 8th. i believe it was in this vacation, or in the october term, that i began every evening to read thucydides very carefully, as my notes are marked 1822 and 1823. on august 27 i find that i was reading ovid's fasti. "in mathematics i find the equation x + y = a, x^q + y^q = b, caustics, calculus of variations, partial differentials, aberration of light, motions of comets, various optical constructions computed with spherical aberrations, particular solutions, mechanics of solid bodies, attractions of shells, chances, ivory's attraction-theorem, lunar theory (algebraical), degrees across meridian, theoretical refraction, newton's 3rd book, investigation of the tides in a shallow equatoreal canal, from which i found that there would be low-water under the moon, metacentres, rotation of a solid body round three axes, attractions of spheroids of variable density, finite differences, and complete figure of the earth. there is also a good deal of investigation of a mathematical nature not connected with college studies, as musical chords, organ-pipes, sketch for a computing machine (suggested by the publications relating to babbage's), sketch of machine for solving equations. in august there is a plan of a ms. on the differential calculus, which it appears i wrote then: one on the figure of the earth written about august 15th; one on tides, sept. 25th; one on newton's principia with algebraical additions, nov. 1st. on sept. 6th and 10th there are lunar distances observed with rothman's sextant and completely worked out; for these i prepared a printed skeleton form, i believe my first. on december 13th there are references to books on geology (conybeare and phillips, and parkinson) which i was beginning to study. on july 27th, being the day on which i completed my 21st year, i carefully did nothing. "another subject partly occupied my thoughts, which, though not (with reference to practical science) very wise, yet gave me some cambridge celebrity. in july 1819 i had (as before mentioned) sketched a plan for constructing reflecting telescopes with silvered glass, and had shewn it afterwards to mr peacock. i now completed the theory of this construction by correcting the aberrations, spherical as well as chromatic. on july 13th, 1822, i drew up a paper about it for mr peacock. he approved it much, and in some way communicated it to mr (afterwards sir john) herschel. i was soon after introduced to herschel at a breakfast with mr peacock: and he approved of the scheme generally. on august 5th i drew up a complete mathematical paper for the cambridge philosophical society, which i entrusted to mr peacock. the aberrations, both spherical and chromatic, are here worked out very well. on nov. 25th it was read at the meeting of the philosophical society, and was afterwards printed in their transactions: this was my first printed memoir. before this time however i had arranged to try the scheme practically. mr peacock had engaged to bear the expense, but i had no occasion to ask him. partly (i think) through drinkwater, i communicated with an optician named bancks, in the strand, who constructed the optical part. i subsequently tried my telescope, but it would not do. the fault, as i had not and have not the smallest doubt, depends in some way on the crystallization of the mercury silvering. it must have been about this time that i was introduced to mr (afterwards sir james) south, at a party at mr peacock's rooms. he advised me to write to tulley, a well-known practical optician, who made me some new reflectors, &c. (so that i had two specimens, one gregorian, the other cassegrainian). however the thing failed practically, and i was too busy ever after to try it again. "during the october term i had no pupils. i kept my second act on nov. 6 (opponents hamilton, rusby, field), and an opponency against jeffries on nov. 7. i attended the questionists' examinations. i seem to have lived a very comfortable idle life. the commemoration day was dec. 18th, when i received a prize, and the next day i walked to bury. on jan. 4th, 1823, i returned to cambridge, and until the b.a. examination i read novels and played cards more than at any other time in college. "on thursday, jan. 9th, 1823, the preliminary classes, for arrangement of details of the b.a. examination, were published. the first class, airy, drinkwater, jeffries, mason. as far as i remember, the rule was then, that on certain days the classes were grouped (in regard to identity of questions given to each group) thus: 1st, {2nd/3rd}, {4th/5th} &c., and on certain other days thus: {1st/2nd}, {3rd/4th}, &c. on saturday, jan. 11th, i paid fees. on monday, jan. 13th, the proceedings of examination began by a breakfast in the combination room. after this, gibson gave me breakfast every day, and buckle gave me and some others a glass of wine after dinner. the hours were sharp, the season a cold one, and no fire was allowed in the senate house where the examination was carried on (my place was in the east gallery), and altogether it was a severe time. "the course of examination was as follows: "monday, jan. 13th. 8 to 9, printed paper of questions by mr hind (moderator); half-past 9 to 11, questions given orally; 1 to 3, ditto; 6 to 9, paper of problems at mr higman's rooms. "tuesday, jan. 14th. 8 to 9, higman's paper; half-past 9 to 11, questions given orally; 1 to 3, ditto; 6 to 9, paper of problems in sidney college hall. "wednesday, jan. 15th. questions given orally 8 to 9 and 1 to 3, with paper of questions on paley and locke (one question only in each was answered). "thursday, jan. 16th. we went in at 9 and 1, but there seems to have been little serious examination. "friday, jan. 17. on this day the brackets or classes as resulting from the examination were published, 1st bracket airy, 2nd bracket jeffries, 3rd bracket drinkwater, fisher, foley, mason, myers. "on saturday, jan. 18th, the degrees were conferred in the usual way. it had been arranged that my brother and sister should come to see me take my degree of b.a., and i had asked gibson to conduct them to the senate house gallery: but mr hawkes (a trinity fellow) found them and stationed them at the upper end of the senate house. after the preliminary arrangements of papers at the vice-chancellor's table, i, as senior wrangler, was led up first to receive the degree, and rarely has the senate house rung with such applause as then filled it. for many minutes, after i was brought in front of the vice-chancellor, it was impossible to proceed with the ceremony on account of the uproar. i gave notice to the smith's prize electors of my intention to 'sit' for that prize, and dined at rothman's rooms with drinkwater, buckle, and others. on monday, jan. 20th, i was examined by professor woodhouse, for smith's prize, from 10 to 1. i think that the only competitor was jeffries. on tuesday i was examined by prof. turton, 10 to 1, and on wednesday by prof. lax, 10 to 1. on thursday, jan. 23rd, i went to bury by coach, on one of the coldest evenings that i ever felt. "mr peacock had once recommended me to sit for the chancellor's medal (classical prize). but he now seemed to be cool in his advice, and i laid aside all thought of it." * * * * * it seems not out of place to insert here a copy of some "cambridge reminiscences" written by airy, which will serve to explain the acts and opponencies referred to in the previous narrative, and other matters. the acts. the examination for b.a. degrees was preceded, in my time, by keeping two acts, in the schools under the university library: the second of them in the october term immediately before the examination; the first (i think) in the october term of the preceding year. these acts were reliques of the disputations of the middle ages, which probably held a very important place in the discipline of the university. (there seems to be something like them in some of the continental universities.) the presiding authority was one of the moderators. i apprehend that the word "moderator" signified "president," in which sense it is still used in the kirk of scotland; and that it was peculiarly applied to the presidency of the disputations, the most important educational arrangement in the university. the moderator sent a summons to the "respondent" to submit three subjects for argument, and to prepare to defend them on a given day: he also named three opponents. this and all the following proceedings were conducted in latin. for my act of 1822, nov. 6, i submitted the following subjects: "recte statuit newtonus in principiis suis mathematicis, libro primo, sectione undecimã¢." "recte statuit woodius de iride." "recte statuit paleius de obligationibus." the opponents named to attack these assertions were hamilton of st john's, rusby of st catharine's, field of trinity. it was customary for the opponents to meet at tea at the rooms of the senior opponent, in order to discuss and arrange their arguments; the respondent was also invited, but he was warned that he must depart as soon as tea would be finished: then the three opponents proceeded with their occupation. as i have acted in both capacities, i am able to say that the matter was transacted in an earnest and business-like way. indeed in the time preceding my own (i know not whether in my own time) the assistance of a private tutor was frequently engaged, and i remember hearing a senior m.a. remark that my college tutor (james d. hustler) was the best crammer for an act in the university. at the appointed time, the parties met in the schools: the respondent first read a latin thesis on any subject (i think i took some metaphysical subject), but nobody paid any attention to it: then the respondent read his first dogma, and the first opponent produced an argument against it, in latin. after this there were repeated replies and rejoinders, all in vivã¢ voce latin, the moderator sometimes interposing a remark in latin. when he considered that one argument was disposed of, he called for another by the words "probes aliter." the arguments were sometimes shaped with considerable ingenuity, and required a clear head in the respondent. when all was finished, the moderator made a complimentary remark to the respondent and one to the first opponent (i forget whether to the second and third). in my respondency of 1822, november 6, the compliment was, "quaestiones tuas summo ingenio et acumine defendisti, et in rebus mathematicis scientiam planã¨ mirabilem ostendisti." in an opponency (i forget when) the compliment was, "magno ingenio argumenta tua et construxisti et defendisti." the acts of the high men excited much interest among the students. at my acts the room was crowded with undergraduates. i imagine that, at a time somewhat distant, the maintenance of the acts was the only regulation by which the university acted on the studies of the place. when the acts had been properly kept, license was given to the father of the college to present the undergraduate to the vice-chancellor, who then solemnly admitted him "ad respondendum quaestioni." there is no appearance of collective examination before this presentation: what the "quaestio" might be, i do not know. still the undergraduate was not b.a. the quaestio however was finished and approved before the day of a certain congregation, and then the undergraduate was declared to be "actualiter in artibus baccalaureum." probably these regulations were found to be insufficient for the control of education, and the january examination was instituted. i conjecture this to have been at or shortly before the date of the earliest triposes recorded in the cambridge calendar, 1748. the increasing importance of the january examination naturally diminished the value of the acts in the eyes of the undergraduates; and, a few years after my m.a. degree, it was found that the opponents met, not for the purpose of concealing their arguments from the respondent, but for the purpose of revealing them to him. this led to the entire suppression of the system. the most active man in this suppression was mr whewell: its date must have been near to 1830. the shape in which the arguments were delivered by an opponent, reading from a written paper, was, "si (quoting something from the respondent's challenge), &c., &c. cadit quaestio; sed (citing something else bearing on the subject of discussion), valet consequentia; ergo (combining these to prove some inaccuracy in the respondent's challenge), valent consequentia et argumentum." nobody pretended to understand these mystical terminations. apparently the original idea was that several acts should be kept by each undergraduate; for, to keep up the number (as it seemed), each student had to gabble through a ridiculous form "si quaestiones tuae falsae sint, cadit quaestio:--sed quaestiones tuae falsae sunt, ergo valent consequentia et argumentum." i have forgotten time and place when this was uttered. the senate-house examination. the questionists, as the undergraduates preparing for b.a. were called in the october term, were considered as a separate body; collected at a separate table in hall, attending no lectures, but invited to attend a system of trial examinations conducted by one of the tutors or assistant-tutors. from the acts, from the annual college examinations, and (i suppose) from enquiries in the separate colleges, the moderators acquired a general idea of the relative merits of the candidates for honours. guided by this, the candidates were divided into six classes. the moderators and assistant examiners were provided each with a set of questions in manuscript (no printed papers were used for honours in the senate house; in regard to the [greek: hoi polloi] i cannot say). on the monday on which the examination began, the father of the college received all the questionists (i believe), at any rate all the candidates for honours, at breakfast in the combination room at 8 o'clock, and marched them to the senate house. my place with other honour-men was in the east gallery. there one examiner took charge of the 1st and 2nd classes united, another examiner took the 3rd and 4th classes united, and a third took the 5th and 6th united. on tuesday, one examiner took the 1st class alone, a second took the 2nd and 3rd classes united, a third took the 4th and 5th classes united, and a fourth took the 6th class alone. on wednesday, thursday, and friday the changes were similar. and, in all, the questioning was thus conducted. the examiner read from his manuscript the first question. those who could answer it proceeded to write out their answers, and as soon as one had finished he gave the word "done"; then the examiner read out his second question, repeating it when necessary for the understanding by those who took it up more lately. and so on. i think that the same process was repeated in the afternoon; but i do not remember precisely. in this manner the examination was conducted through five days (monday to friday) with no interruption except on friday afternoon. it was principally, perhaps entirely, bookwork. but on two _evenings_ there were printed papers of problems: and the examination in these was conducted just as in the printed papers of the present day: but in the private college rooms of the moderators. and there, wine and other refreshments were offered to the examinees. how this singular custom began, i know not. the order of merit was worked out on friday afternoon and evening, and was in some measure known through the university late in the evening. i remember mr peacock coming to a party of examinees and giving information on several places. i do not remember his mentioning mine (though undoubtedly he did) but i distinctly remember his giving the wooden spoon. on the saturday morning at 8 o'clock the manuscript list was nailed to the door of the senate-house. the form of further proceedings in the presentation for degree (ad respondendum quaestioni) i imagine has not been much altered. the kneeling before the vice-chancellor and placing hands in the vice-chancellor's hands were those of the old form of doing homage. the form of examination which i have described was complicated and perhaps troublesome, but i believe that it was very efficient, possibly more so than the modern form (established i suppose at the same time as the abolition of the acts). the proportion of questions now answered to the whole number set is ridiculously small, and no accurate idea of relative merit can be formed from them. the college hall. when i went up in 1819, and for several years later, the dinner was at 1/4 past 3. there was no supplementary dinner for special demands. boat-clubs i think were not invented, even in a plain social way, till about 1824 or 1825; and not in connection with the college till some years later. some of the senior fellows spoke of the time when dinner was at 2, and regretted the change. there was supper in hall at 9 o'clock: i have known it to be attended by a few undergraduates when tired by examinations or by evening walks; and there were always some seniors at the upper table: i have occasionally joined them, and have had some very interesting conversations. the supper was cold, but hot additions were made when required. one little arrangement amused me, as shewing the ecclesiastical character of the college. the fasts of the church were to be strictly kept, and there was to be no dinner in hall. it was thus arranged. the evening chapel service, which was usually at 5-1/2 (i think), was held at 3; and at 4 the ordinary full meal was served in hall, but as it followed the chapel attendance it was held to be supper; and there was no subsequent meal. there were no chairs whatever in hall, except the single chair of the vice-master at the head of the table on the dais and that of the senior dean at the table next the east wall. all others sat on benches. and i have heard allusions to a ludicrous difficulty which occurred when some princesses (of the royal family) dined in the hall, and it was a great puzzle how to get them to the right side of the benches. the sizars dined after all the rest; their dinner usually began soon after 4. for the non-foundationists a separate dinner was provided, as for pensioners. but for the foundationists, the remains of the fellows' dinner were brought down; and i think that this provision was generally preferred to the other. the dishes at all the tables of undergraduates were of pewter, till a certain day when they were changed for porcelain. i cannot remember whether this was at the time when they became questionists (in the october term), or at the time when they were declared "actualiter esse in artibus baccalaureos" (in the lent term). up to the questionist time the undergraduate scholars had no mixture whatever; they were the only pure table in the hall: and i looked on this as a matter very valuable for the ultimate state of the college society. but in the october term, those who were to proceed to b.a. were drafted into the mixed body of questionists: and they greatly disliked the change. they continued so till the lent term, when they were formally invited by the bachelor scholars to join the upper table. mathematical subjects of study and examination. in the october term 1819, the only books on pure mathematics were:--euclid generally, algebra by dr wood (formerly tutor, but in 1819 master, of st john's college), vince's fluxions and dealtry's fluxions, woodhouse's and other trigonometries. not a whisper passed through the university generally on the subject of differential calculus; although some papers (subsequently much valued) on that subject had been written by mr woodhouse, fellow of caius college; but their style was repulsive, and they never took hold of the university. whewell's mechanics (1819) contains a few and easy applications of the differential calculus. the books on applied mathematics were wood's mechanics, whewell's mechanics, wood's optics, vince's hydrostatics, vince's astronomy, woodhouse's plane astronomy (perhaps rather later), the first book of newton's principia: i do not remember any others. these works were undoubtedly able; and for the great proportion of university students going into active life, i do not conceal my opinion that books constructed on the principles of those which i have cited were more useful than those exclusively founded on the more modern system. for those students who aimed at the mastery of results more difficult and (in the intellectual sense) more important, the older books were quite insufficient. more aspiring students read, and generally with much care, several parts of newton's principia, book i., and also book iii. (perhaps the noblest example of geometrical form of cosmical theory that the world has seen). i remember some questions from book iii. proposed in the senate-house examination 1823. in the october term 1819, i went up to the university. the works of wood and vince, which i have mentioned, still occupied the lecture-rooms. but a great change was in preparation for the university course of mathematics. during the great continental war, the intercourse between men of science in england and in france had been most insignificant. but in the autumn of 1819, three members of the senate (john herschel, george peacock, and charles babbage) had entered into the mathematical society of paris, and brought away some of the works on pure mathematics (especially those of lacroix) and on mechanics (principally poisson's). in 1820 they made a translation of lacroix's differential calculus; and they prepared a volume of examples of the differential and integral calculus. these were extensively studied: but the form of the college examinations or the university examinations was not, i think, influenced by them in the winter 1820-1821 or the two following terms. but in the winter 1821-1822 peacock was one of the moderators; and in the senate-house examination, january 1822, he boldly proposed a paper of important questions entirely in the differential calculus. this was considered as establishing the new system in the university. in january 1823, i think the two systems were mingled. though i was myself subject to that examination, i grieve to say that i have forgotten much of the details, except that i well remember that some of the questions referred to newton, book iii. on the lunar theory. to these i have already alluded. no other work occurs to me as worthy of mention, except woodhouse's lunar theory, entirely founded on the differential calculus. the style of this book was not attractive, and it was very little read. chapter iii. at trinity college, cambridge, from his taking his b.a. degree to his taking charge of the cambridge observatory as plumian professor. from january 18th, 1823, to march 15th, 1828. "on jan. 30th, 1823, i returned to cambridge. i had already heard that i had gained the 1st smith's prize, and one of the first notifications to me on my return was that the walker's good-conduct prize of _â£10_ was awarded to me. "i remember that my return was not very pleasant, for our table in hall was half occupied by a set of irregular men who had lost terms and were obliged to reside somewhat longer in order to receive the b.a. degree. but at the time of my completing the b.a. degree (which is not till some weeks after the examination and admission) i with the other complete bachelors was duly invited to the table of the b.a. scholars, and that annoyance ended. "the liberation from undergraduate study left me at liberty generally to pursue my own course (except so far as it was influenced by the preparation for fellowship examination), and also left me at liberty to earn more money, in the way usual with the graduates, by taking undergraduate pupils. mr peacock recommended me to take only four, which occupied me four hours every day, and for each of them i received 20 guineas each term. my first pupils, for the lent and easter terms, were williamson (afterwards head master of westminster school), james parker (afterwards q.c. and vice-chancellor), bissett, and clinton of caius. to all these i had been engaged before taking my b.a. degree. "i kept up classical subjects. i have a set of notes on the [greek: ploutos] and [greek: nephelai] of aristophanes, finished on mar. 15th, 1823, and i began my daily writing of latin as usual on feb. 8th. in mathematics i worked very hard at lunar and planetary theories. i have two ms. books of lunar theory to the 5th order of small quantities, which however answered no purpose except that of making me perfectly familiar with that subject. i worked well, upon my quires, the figure of saturn supposed homogeneous as affected by the attraction of his ring, and the figure of the earth as heterogeneous, and the calculus of variations. i think it was now that i wrote a ms. on constrained motion. "on mar. 17th, 1823, i was elected fellow of the cambridge philosophical society. on may 9th a cast of my head was taken for dr elliotson, an active phrenologist, by deville, a tradesman in the strand. "i had long thought that i should like to visit scotland, and on my once saying so to my mother, she (who had a most kindly recollection of alnwick) said in a few words that she thought i could not do better. i had therefore for some time past fully determined that as soon as i had sufficient spare time and money enough i would go to scotland. the interval between the end of easter term and the usual beginning with pupils in the long vacation offered sufficient time, and i had now earned a little money, and i therefore determined to go, and invited my sister to accompany me. i had no private introductions, except one from james parker to mr reach, a writer of inverness: some which drinkwater sent being too late. on may 20th we went by coach to stamford; thence by pontefract and oulton to york, where i saw the cathedral, which _then_ disappointed me, but i suppose that we were tired with the night journey. then by newcastle to alnwick, where we stopped for the day to see my birthplace. on may 24th to edinburgh. on this journey i remember well the stone walls between the fields, the place (in yorkshire) where for the first time in my life i saw rock, the hambleton, kyloe, cheviot and pentland hills, arthur's seat, but still more strikingly the revolving inch keith light. at edinburgh i hired a horse and gig for our journey in scotland, and we drove by queensferry to kinross (where for the first time in my life i saw clouds on the hills, viz. on the lomond hills), and so to perth. thence by dunkeld and killicrankie to blair athol (the dreariness of the drumochter pass made a strong impression on me), and by aviemore (where i saw snow on the mountains) to inverness. here we received much kindness and attention from mr reach, and after visiting the falls of foyers and other sights we went to fort augustus and fort william. we ascended ben nevis, on which there was a great deal of snow, and visited the vitrified fort in glen nevis. then by inverary to tarbet, and ascended ben lomond, from whence we had a magnificent view. we then passed by loch achray to glasgow, where we found james parker's brother (his father, of the house of macinroy and parker, being a wealthy merchant of glasgow). on june 15th to mr parker's house at blochairn, near glasgow (on this day i heard dr chalmers preach), and on the 17th went with the family by steamer (the first that i had seen) to fairly, near largs. i returned the gig to edinburgh, visited arran and bute, and we then went by coach to carlisle, and by penrith to keswick (by the old road: never shall i forget the beauty of the approach to keswick). after visiting ambleside and kendal we returned to cambridge by way of leeds, and posted to bury on the 28th june. the expense of this expedition was about _â£81_. it opened a completely new world to me. "i had little time to rest at bury. in the preceding term drinkwater, buckle, and myself, had engaged to go somewhere into the country with pupils during the long vacation (as was customary with cambridge men). buckle however changed his mind. drinkwater went to look for a place, fixed on swansea, and engaged a house (called the cambrian hotel, kept by a captain jenkins). on the morning of july 2nd i left bury for london and by mail coach to bristol. on the morning of july 3rd by steamer to swansea, and arrived late at night. i had then five pupils: parker, harman lewis (afterwards professor in king's college, london), pierce morton, gibson, and guest of caius (afterwards master of the college). drinkwater had four, viz. two malkins (from bury), elphinstone (afterwards m.p.), and farish (son of professor farish). we lived a hard-working strange life. my pupils began with me at six in the morning: i was myself reading busily. we lived completely _en famille_, with two men-servants besides the house establishment. one of our first acts was to order a four-oared boat to be built, fitted with a lug-sail: she was called the granta of swansea. in the meantime we made sea excursions with boats borrowed from ships in the port. on july 23rd, with a borrowed boat, we went out when the sea was high, but soon found our boat unmanageable, and at last got into a place where the sea was breaking heavily over a shoal, and the two of the crew who were nearest to me (a. malkin and lewis), one on each side, were carried out: they were good swimmers and we recovered them, though with some trouble: the breaker had passed quite over my head: we gained the shore and the boat was taken home by land. when our own boat was finished, we had some most picturesque adventures at the mumbles, aberavon, caswell bay, ilfracombe, and tenby. from all this i learnt navigation pretty well. the mixture of hard study and open-air exertion seemed to affect the health of several of us (i was one): we were covered with painful boils. "my latin-writing began again on july 25th: i have notes on demosthenes, lucretius, and greek history. in mathematics i find chances, figure of the earth with variable density, differential equations, partial differentials, sketch for an instrument for shewing refraction, and optical instruments with effects of chromatic aberration. in august there occurred an absurd quarrel between the fellows of trinity and the undergraduates, on the occasion of commencing the building of king's court, when the undergraduates were not invited to wine, and absented themselves from the hall. "there were vacant this year (1823) five fellowships in trinity college. in general, the b.a.'s of the first year are not allowed to sit for fellowships: but this year it was thought so probable that permission would be given, that on sept. 2nd mr higman, then appointed as tutor to a third 'side' of the college, wrote to me to engage me as assistant mathematical tutor in the event of my being elected a fellow on oct. 1st, and i provisionally engaged myself. about the same time i had written to mr peacock, who recommended me to sit, and to mr whewell, who after consultation with the master (dr wordsworth), discouraged it. as there was no absolute prohibition, i left swansea on sept. 11th (before my engagement to my pupils was quite finished) and returned to cambridge by gloucester, oxford, and london. i gave in my name at the butteries as candidate for fellowship, but was informed in a day or two that i should not be allowed to sit. on sept. 19th i walked to bury. "i walked back to cambridge on oct. 17th, 1823. during this october term i had four pupils: neate, cankrein, turner (afterwards 2nd wrangler and treasurer of guy's hospital), and william hervey (son of the marquis of bristol). in the lent term i had four (neate, cankrein, turner, clinton). in the easter term i had three (neate, cankrein, turner). "my daily writing of latin commenced on oct. 27th. in november i began re-reading sophocles with my usual care. in mathematics i find investigations of motion in a resisting medium, form of saturn, draft of a paper about an instrument for exhibiting the fundamental law of refraction (read at the philosophical society by mr peacock on nov. 10th, 1823), optics, solid geometry, figure of the earth with variable density, and much about attractions. i also in this term wrote a ms. on the calculus of variations, and one on wood's algebra, 2nd and 4th parts. i have also notes of the temperature of mines in cornwall, something on the light of oil-gas, and reminiscences of swansea in a view of oswick bay. in november i attended professor sedgwick's geological lectures. "at some time in this term i had a letter from mr south (to whom i suppose i had written) regarding the difficulty of my telescope: he was intimately acquainted with tulley, and i suppose that thus the matter had become more fully known to him. he then enquired if i could visit him in the winter vacation. i accordingly went from bury, and was received by him at his house in blackman street for a week or more with great kindness. he introduced me to sir humphrey davy and many other london savans, and shewed me many london sights and the greenwich observatory. i also had a little practice with his own instruments. he was then on intimate terms with mr herschel (afterwards sir john herschel), then living in london, who came occasionally to observe double stars. this was the first time that i saw practical astronomy. it seems that i borrowed his mountain barometer. in the lent term i wrote to him regarding the deduction of the parallax of mars, from a comparison of the relative positions of mars and 46 leonis, as observed by him and by rumker at paramatta. my working is on loose papers. i see that i have worked out perfectly the interpolations, the effects of uncertainty of longitude, &c., but i do not see whether i have a final result. "in jan. 1824, at playford, i was working on the effects of separating the two lenses of an object-glass, and on the kind of eye-piece which would be necessary: also on spherical aberrations and saturn's figure. on my quires at cambridge i was working on the effects of separating the object-glass lenses, with the view of correcting the secondary spectrum: and on jan. 31st i received some numbers (indices of refraction) from mr herschel, and reference to fraunhofer's numbers. "about this time it was contemplated to add to the royal observatory of greenwich two assistants of superior education. whether this scheme was entertained by the admiralty, the board of longitude, or the royal society, i do not know. somehow (i think through mr peacock) a message from mr herschel was conveyed to me, acquainting me of this, and suggesting that i should be an excellent person for the principal place. to procure information, i went to london on saturday, feb. 7th, sleeping at mr south's, to be present at one of sir humphrey davy's saturday evening soirã©es (they were then held every saturday), and to enquire of sir h. davy and dr young. when i found that succession to the post of astronomer royal was not considered as distinctly a consequence of it, i took it coolly, and returned the next night. the whole proposal came to nothing. "at this time i was engaged upon differential equations, mountain barometer problem and determination of the height of the gogmagogs and several other points, investigations connected with laplace's calculus, spherical aberration in different planes, geology (especially regarding derbyshire, which i proposed to visit), and much of optics. i wrote a draft of my paper on the figure of saturn, and on mar. 15th, 1824, it was read at the philosophical society under the title of 'on the figure assumed by a fluid homogeneous mass, whose particles are acted on by their mutual attraction, and by small extraneous forces,' and is printed in their memoirs. i also wrote a draft of my paper on achromatic eye-pieces, and on may 17th, 1824, it was read at the philosophical society under the title of 'on the principles and construction of the achromatic eye-pieces of telescopes, and on the achromatism of microscopes,' including also the effects of separating the lenses of the object-glass. it is printed in their memoirs. "amongst miscellaneous matters i find that on mar. 22nd of this year i began regularly making extracts from the books of the book society, a practice which i continued to march 1826. on mar. 27th, a very rainy day, i walked to bury to attend the funeral of my uncle william biddell, near diss, and on mar. 30th i walked back in rain and snow. on feb. 24th i dined with cubitt in cambridge. on may 21st i gave a certificate to rogers (the assistant in crosse's school, and my instructor in mathematics), which my mother amplified much, and which i believe procured his election as master of walsall school. on june 23rd i went to bury. the speeches at bury school, which i wished to attend, took place next day." at this point of his autobiography the writer continues, "now came one of the most important occurrences in my life." the important event in question was his acquaintance with richarda smith, the lady who afterwards became his wife. the courtship was a long one, and in the autobiography there are various passages relating to it, all written in the most natural and unaffected manner, but of somewhat too private a nature for publication. it will therefore be convenient to digress from the straight path of the narrative in order to insert a short memoir of the lady who was destined to influence his life and happiness in a most important degree. richarda smith was the eldest daughter of the rev. richard smith, who had been a fellow of trinity college, cambridge, but was at this time private chaplain to the duke of devonshire, and held the small living of edensor, near chatsworth, in derbyshire. he had a family of two sons and seven daughters, whom he had brought up and educated very carefully. several of his daughters were remarkable both for their beauty and accomplishments. richarda smith was now in her 20th year, and the writer of the autobiography records that "at matlock we received great attention from mr chenery: in speaking of mr smith i remember his saying that mr smith had a daughter whom the duke of devonshire declared to be the most beautiful girl he ever saw." this was before he had made the acquaintance of the family. airy was at this time on a walking tour in derbyshire with his brother william, and they were received at edensor by mr smith, to whom he had letters of introduction. he seems to have fallen in love with miss smith "at first sight," and within two days of first seeing her he made her an offer of marriage. neither his means nor his prospects at that time permitted the least idea of an immediate marriage, and mr smith would not hear of any engagement. but he never had the least doubt as to the wisdom of the choice that he had made: he worked steadily on, winning fame and position, and recommending his suit from time to time to miss smith as opportunity offered, and finally married her, nearly six years after his first proposal. his constancy had its reward, for he gained a most charming and affectionate wife. as he records at the time of his marriage, "my wife was aged between 25 and 26, but she scarcely appeared more than 18 or 20. her beauty and accomplishments, her skill and fidelity in sketching, and above all her exquisite singing of ballads, made a great sensation in cambridge." their married life lasted 45 years, but the last six years were saddened by the partial paralysis and serious illness of lady airy. the entire correspondence between them was most carefully preserved, and is a record of a most happy union. the letters were written during his numerous journeys and excursions on business or pleasure, and it is evident that his thoughts were with her from the moment of their parting. every opportunity of writing was seized with an energy and avidity that shewed how much his heart was in the correspondence. nothing was too trivial or too important to communicate to his wife, whether relating to family or business matters. the letters on both sides are always full of affection and sympathy, and are written in that spirit of confidence which arises from a deep sense of the value and necessity of mutual support in the troubles of life. and with his active and varied employments and his numerous family there was no lack of troubles. they were both of them simple-minded, sensible, and practical people, and were very grateful for such comforts and advantages as they were able to command, but for nothing in comparison with their deep respect and affection for one another. both by natural ability and education she was well qualified to enter into the pursuits of her husband, and in many cases to assist him. she always welcomed her husband's friends, and by her skill and attractive courtesy kept them well together. she was an admirable letter-writer, and in the midst of her numerous domestic distractions always found time for the duties of correspondence. in conversation she was very attractive, not so much from the wit or brilliancy of her remarks as from the brightness and interest with which she entered into the topics under discussion, and from the unfailing grace and courtesy with which she attended to the views of others. this was especially recognized by the foreign astronomers and men of science who from time to time stayed as guests at the observatory and to whom she acted as hostess. although she was not an accomplished linguist yet she was well able to express herself in french and german, and her natural good sense and kindliness placed her guests at their ease, and made them feel themselves (as indeed they were) welcomed and at home. her father, the rev. richard smith, was a man of most cultivated mind, and of the highest principles, with a keen enjoyment of good society, which the confidence and friendship of his patron the duke of devonshire amply secured to him, both at chatsworth and in london. he had a deep attachment to his alma mater of cambridge, and though not himself a mathematician he had a great respect for the science of mathematics and for eminent mathematicians. during the long courtship already related mr smith conceived the highest respect for airy's character, as well as for his great repute and attainments, and expressed his lively satisfaction at his daughter's marriage. thus on january 20th, 1830, he wrote to his intended son-in-law as follows: "i have little else to say to you than that i continue with heartfelt satisfaction to reflect on the important change about to take place in my dear daughter's situation. a father must not allow himself to dilate on such a subject: of course i feel confident that you will have no reason to repent the irrevocable step you have taken, but from the manner in which richarda has been brought up, you will find such a helpmate in her as a man of sense and affection would wish to have, and that she is well prepared to meet the duties and trials (for such must be met with) of domestic life with a firm and cultivated mind, and the warm feelings of a kind heart. her habits are such as by no means to lead her to expensive wishes, nor will you i trust ever find it necessary to neglect those studies and pursuits upon which your reputation and subsistence are chiefly founded, to seek for idle amusements for your companion. i must indulge no further in speaking of her, and have only at present to add that i commit in full confidence into your hands the guardianship of my daughter's happiness." and on april 5th, 1830, shortly after their marriage, he wrote to his daughter thus: "if thinking of you could supply your place amongst us you would have been with us unceasingly, for we have all of us made you the principal object of our thoughts and our talk since you left us, and i travelled with you all your journey to your present delightful home. we had all but one feeling of the purest pleasure in the prospect of the true domestic comfort to which we fully believe you to be now gone, and we rejoice that all your endearing qualities will now be employed to promote the happiness of one whom we think so worthy of them as your dear husband, who has left us in the best opinion of his good heart, as well as his enlightened and sound understanding. his late stay with us has endeared him to us all. never did man enter into the married state from more honourable motives, or from a heart more truly seeking the genuine happiness of that state than mr airy, and he will, i trust, find his reward in you from all that a good wife can render to the best of husbands, and his happiness be reflected on yourself." it would be difficult to find letters of more genuine feeling and satisfaction, or more eloquently expressed, than these. the narrative of the autobiography will now be resumed. "i had been disappointed two years before of an expedition to derbyshire. i had wished still to make it, and my brother wished to go: and we determined to make it this year (1824). we were prepared with walking dresses and knapsacks. i had well considered every detail of our route, and was well provided with letters of introduction, including one to the rev. r. smith of edensor. on june 29th we started by coach to newmarket and walked through the fens by ramsay to peterborough. then by stamford and ketton quarries to leicester and derby. here we were recognized by a mr calvert, who had seen me take my degree, and he invited us to breakfast, and employed himself in shewing us several manufactories, &c. to which we had been denied access when presenting ourselves unsupported. we then went to belper with an introduction from mr calvert to jedediah strutt: saw the great cotton mills, and in the evening walked to matlock. up to this time the country of greatest interest was the region of the fens about ramsay (a most remarkable district), but now began beauty of scenery. on july 9th we walked by rowsley and haddon hall over the hills to edensor, where we stayed till the 12th with mr smith. we next visited hathersage, castleton, and marple (where i wished to see the canal aqueduct), and went by coach to manchester, and afterwards to liverpool. here dr traill recommended us to see the pontycyssylte aqueduct, and we went by chester and wrexham to rhuabon, saw the magnificent work, and proceeded to llangollen. thence by chester and northwich (where we descended a salt-mine) to macclesfield. then to the ecton mine (of which we saw but little) through dovedale to ashbourn, and by coach to derby. on july 24th to birmingham, where we found mr guest, lodged in his house, and were joined by my pupil guest. here we were fully employed in visiting the manufactures, and then went into the iron country, where i descended a pit in the staffordshire main. thence by coach to cambridge, where i stopped to prepare for the fellowship examination. "i had two pupils in this portion of the long vacation, turner and dobbs. on august 2nd my writing of latin began regularly as before. my principal mathematics on the quires are optics. on august 25th i made experiments on my left eye, with good measures, and on aug. 26th ordered a cylindrical lens of peters, a silversmith in the town, which i believe was never made. subsequently, while at playford, i ordered cylindrical lenses of an artist named fuller, living at ipswich, and these were completed in november, 1824. "my letter to the examiners, announcing my intention of sitting for fellowship (which like all other such documents is preserved on my quires) was delivered on sept 21st. the examination took place on sept. 22nd and the two following days. on oct. 1st, 1824, at the usual hour of the morning, i was elected fellow. there were elected at the same time t.b. macaulay (afterwards lord macaulay), who was a year senior to me in college, and i think field of my own year. i drew up my letter of acknowledgment to the electors. on oct. 2nd at 9 in the morning i was admitted fellow with the usual ceremonies, and at 10 i called on the electors with my letter of acknowledgment. i immediately journeyed to derbyshire, paid a visit at edensor, and returned by sheffield. "on oct. 11th (it having been understood with mr higman that my engagement as assistant mathematical tutor stood) the master sent for me to appoint me and to say what was expected as duty of the office. he held out to me the prospect of ultimately succeeding to the tutorship, and i told him that i hoped to be out of college before that time. "about this time the 'athenaeum,' a club of a scientific character, was established in london, and i was nominated on it, but i declined" (oct. 14th). in this year (1824) i commenced account with a banker by placing _â£110_ in the hands of messrs mortlock and co. on oct. 16th i walked to bury, and after a single day's stay there returned to cambridge. "on oct. 23rd, 1824,1 began my lectures as mathematical assistant tutor. i lectured the senior sophs and junior sophs on higman's side. the number of senior sophs was 21. besides this i took part in the 'examinations of the questionists,' a series of exercises for those who were to take the bachelor's degree in the next january. i examined in mechanics, newton, and optics. i had also as private pupils turner, dobbs, and cooper. i now ceased from the exercise which i had followed with such regularity for five years, namely that of daily writing latin. in its stead i engaged a french master (goussel) with whom i studied french with reasonable assiduity for the three terms to june, 1825. "among mathematical investigations i find: theory of the moon's brightness, motion of a body in an ellipse round two centres of force, various differential equations, numerical computation of sin pi from series, numerical computation of sines of various arcs to 18 decimals, curvature of surfaces in various directions, generating functions, problem of sound. i began in the winter a latin essay as competing for the middle bachelors' prize, but did not proceed with it. i afterwards wished that i had followed it up: but my time was fully occupied. "on jan. 28th, 1825, i started for edensor, where i paid a visit, and returned on feb. 2nd. on feb. 4th i wrote to mr clarkson, asking his advice about a profession or mode of life (the cares of life were now beginning to press me heavily, and continued to do so for several years). he replied very kindly, but his answer amounted to nothing. about the same time i had some conversation of the same kind with mr peacock, which was equally fruitless. "on feb. 4th i have investigations of the density of light near a caustic (on the theory of emissions). on feb. 5th i finished a paper about the defect in my eye, which was communicated to the cambridge philosophical society on feb. 21st. mr peacock or mr whewell had some time previously applied to me to write a paper on trigonometry for the encyclopaedia metropolitana, and i had been collecting some materials (especially in regard to its history) at every visit to london, where i read sometimes at the british museum: also in the cambridge libraries. i began this paper (roughly) on feb. 8th, and finished it on mar. 3rd. the history of which i speak, by some odd management of the editors of the encyclopaedia, was never published. the ms. is now amongst the mss. of the royal observatory, greenwich. other subjects on my quires are: theory of musical concords, many things relating to trigonometry and trigonometrical tables, achromatic eye-pieces, equation to the surface bounding the rays that enter my left eye, experiments on percussion. also notes on cumberland and wales (i had already proposed to myself to take a party of pupils in the long vacation to keswick), and notes on history and geology. "i had been in correspondence with dr malkin (master of bury school), who on feb. 8th sent a certificate for my brother william, whom i entered at trinity on peacock's side. on mar. 25th i changed my rooms, quitting those on the ground-floor east side of queen mary's gate for first-floor rooms in neville's court, south side, the easternmost rooms. in this term my lectures lasted from apr. 18th to may 14th. apparently i had only the senior sophs, 19 in number, and the same four pupils (turner, dobbs, cooper, hovenden) as in the preceding term. the only scientific subjects on which i find notes are, a paper on the forms of the teeth of wheels, communicated to the philosophical society on may 2nd; some notes about musical concords, and some examination of a strange piece of iceland spar. on apr. 29th i was elected to the northern institution (of inverness); the first compliment that i received from an extraneous body. "on may 14th i have a most careful examination of my money accounts, to see whether i can make an expedition with my sister into wales. my sister came to cambridge, and on monday, may 23rd, 1825, we started for wales, equipped in the lightest way for a walking expedition. we went by birmingham to shrewsbury: then to the pontycyssylte aqueduct and by various places to bala, and thence by llanrwst to conway. here the suspension bridge was under construction: the mole was made and the piers, but nothing else. then on to bangor, where nine chains of the suspension bridge were in place, and so to holyhead. then by carnarvon to bethgelert, ascending snowdon by the way, and in succession by festiniog, dolgelly, and aberystwyth to hereford (the first time that i had visited it since my father left it). from thence we went by coach to london, and i went on to cambridge on the 23rd of june. "i had arranged to take a party of pupils to keswick, and to take my brother there. mr clarkson had provided me with introductions to mr southey and mr wordsworth. on wednesday, june 29th, 1825, we started, and went by leicester, sheffield, leeds, and kendal, to keswick, calling at edensor on the way. my pupils were cleasby, marshman, clinton, wigram, tottenham, and m. smith. at keswick i passed three months very happily. i saw mr southey's family frequently, and mr wordsworth's occasionally. by continual excursions in the neighbourhood, and by a few excursions to places as distant as bowness, calder bridge, &c. (always climbing the intermediate mountains), i became well acquainted with almost the whole of that beautiful country, excepting some of the s. w. dales. a geological hammer and a mountain barometer were very interesting companions. i had plenty of work with my pupils: i worked a little lunar theory, a little of laplace's equations, something of the figure of the earth, and i wrote out very carefully my trigonometry for the encyclopaedia metropolitana. i read a little of machiavelli, and various books which i borrowed of mr southey. on friday, sept. 30th, my brother and i left for kendal, and after a stay of a few days at edensor, arrived at cambridge on oct. 11th. "on oct. 21st my lectures to the junior sophs began, 39 names, lasting to dec. 13th. those to the senior sophs, 16 names, oct 29th to dec. 10th. i also examined questionists as last year. i have notes about a paper on the connection of impact and pressure, read at the philosophical society on nov. 14th, but not printed, dipping-needle problems, curve described round three centres of force, barometer observations, theory of the figure of the earth with variable density, and effect on the moon, correction to the madras pendulum, wedge with friction, spots seen in my eyes, density of rays near a caustic. in this term i accomplished the preparation of a volume of mathematical tracts on subjects which, either from their absolute deficiency in the university or from the unreadable form in which they had been presented, appeared to be wanted. the subjects of my tracts were, lunar theory (begun oct. 26th, finished nov. 1st), figure of the earth (1st part finished nov. 18th), precession and nutation (my old ms. put in order), and the calculus of variations. i applied, as is frequently done, to the syndicate of the university press for assistance in publishing the work; and they agreed to give me paper and printing for 500 copies. this notice was received from professor turton on nov. 29th, 1825. it was probably also in this year that i drew up an imperfect 'review' of coddington's optics, a work which deserved severe censure: my review was never finished. "in the long vacation at keswick i had six pupils at _â£42_ each. in the october term i had marshman and ogilby at _â£105_ for three terms, and dobbs at _â£75_ for three terms. i had, at mr peacock's suggestion, raised my rate from 60 to 100 guineas for three terms: this prevented some from applying to me, and induced some to withdraw who had been connected with me: but it did me no real hurt, for engrossment by pupils is the worst of all things that can happen to a man who hopes to distinguish himself. on dec. 17th i went to bury, and returned to cambridge on jan. 30th, 1826. "i have the attendance-bills of my lectures to senior sophs (16) from feb. 3rd to feb. 23rd, and to freshmen (40) from feb. 27th to mar. 15. it would appear that i gave but one college-lecture per day (my belief was that i always had two). the tutor's stipend per term was _â£50_. on my quires i find, investigations for the ellipticity of a heterogeneous spheroid when the density is expressed by sin _qc_/_qc_ (the remarkable properties of which i believe i discovered entirely myself, although they had been discovered by other persons), theoretical numbers for precession, nutation, &c., some investigations using laplace's y, hard work on the figure of the earth to the 2nd order,'woodhouse's remaining apparatus,' notes about lambton's and kater's errors, depolarization, notes of papers on depolarization in the phil. trans., magnetic investigations for lieut. foster, isochronous oscillations in a resisting medium, observations on a strange piece of iceland spar. on mar. 7th forwarded preface and title page for my mathematical tracts. "some time in this term i began to think of the possibility of observing the diminution of gravity in a deep mine, and communicated with whewell, who was disposed to join in experiments. my first notion was simply to try the rate of a clock, and the ecton mine was first thought of. i made enquiries about the ecton mine through mr smith (of edensor), and visited the mine, but in the meantime whewell had made enquiries in london and found (principally from dr paris) that the mine of dolcoath near camborne in cornwall would be a better place for the experiment. dr paris wrote to me repeatedly, and ultimately we resolved on trying it there. in my papers on mar. 21st are various investigations about attractions in both mines. on apr. 3rd i went to london, principally to arrange about dolcoath, and during april and may i was engaged in correspondence with sir h. davy (president of the royal society), mr herschel, and dr young (secretary of the board of longitude) about the loan of instruments and pendulums. on apr. 23rd i was practising pendulum-observations (by coincidence); and about this time repeatedly practised transits with a small instrument lent by mr sheepshanks (with whom my acquaintance must have begun no long time before) which was erected under a tent in the fellows' walks. on my quires i find various schemes for graduating thermometers for pendulum experiments. "i find also notes of examination of my brother william, who had come to college last october; and a great deal of correspondence with my mother and sister and mr case, a lawyer, about a troublesome business with mr cropley, an old friend of g. biddell, to whom my father had lent _â£500_ and whose affairs were in chancery. "my lectures in this term were to the junior sophs from apr. 10th to may 13th: they were six in number and not very regular. on apr. 28th i sent to mawman the copy of my trigonometry for the encyclopaedia metropolitana, for which i received _â£42_. i received notice from the press syndicate that the price of my mathematical tracts was fixed at _6s. 6d._: i sold the edition to deighton for _â£70_, and it was immediately published. about this time i have letters from mr herschel and sir h. davy about a paper to be presented to the royal society--i suppose about the figure of the earth to the 2nd order of ellipticity, which was read to the royal society on june 15th. "on saturday, may 13th, 1826, i went to london on the way to dolcoath, and received four chronometers from the royal observatory, greenwich. i travelled by devonport and falmouth to camborne, where i arrived on may 20th and dined at the count-house dinner at the mine. i was accompanied by ibbotson, who was engaged as a pupil, and intended for an engineer. on may 24th whewell arrived, and we took a pendulum and clock down, and on the 30th commenced the observation of coincidences in earnest. this work, with the changing of the pendulums, and sundry short expeditions, occupied nearly three weeks. we had continued the computation of our observations at every possible interval. it is to be understood that we had one detached pendulum swinging in front of a clock pendulum above, and another similarly mounted below; and that the clocks were compared by chronometers compared above, carried down and compared, compared before leaving, and brought up and compared. the upper and lower pendulums had been interchanged. it was found now that the reliance on the steadiness of the chronometers was too great; and a new method was devised, in which for each series the chronometers should make four journeys and have four comparisons above and two below. this arrangement commenced on the 19th june and continued till the 20th. on the 26th we packed the lower instruments, intending to compare the pendulum directly with the upper one, and sent them up the shaft: when an inexplicable occurrence stopped all proceedings. the basket containing all the important instruments was brought up to the surface (in my presence) on fire; some of the instruments had fallen out with their cases burning. whether a superstitious miner had intentionally fired it, or whether the snuff of a candle had been thrown into it, is not known. our labour was now rendered useless. on the 28th i packed up what remained of instruments, left for truro, and arrived at bury on july 1st. during our stay in cornwall i had attended a 'ticketing' or sale of ore at camborne, and we had made expeditions to the n.w. coast, to portreath and illogan, to marazion and st michael's mount, and to penzance and the land's end. on july 3rd i saw mr cropley in bury gaol, and went to cambridge. on the 4th i was admitted a.m., and on the 5th was admitted major fellow. "i had engaged with four pupils to go to orlã©ans in this long vacation: my brother william was also to go. one of my pupils, dobbs, did not join: the other three were tinkler, ogilby, and ibbotson. we left london on july 9th, and travelled by brighton, dieppe, rouen, and paris to orlã©ans. at paris i saw bouvard, pouillet, laplace and arago. i had introductions from mr peacock, mr south, mr herschel, dr young; and from professor sedgwick to an english resident, mr underwood. on the 19th i was established in the house of m. lagarde, protestant minister. here i received my pupils. on the 28th i commenced italian with an italian master: perhaps i might have done more prudently in adhering to french, for i made no great progress. on aug. 2nd i saw a murderer guillotined in the place martroi. the principal investigations on my quires are--investigations about pendulums, calculus of variations, notes for the figure of the earth (encyc. metrop.) and commencement of the article, steam-engine machinery, &c. i picked up various french ballads, read various books, got copies of the marseillaise (this i was obliged to obtain rather secretly, as the legitimist power under charles x. was then at its height) and other music, and particulars of farm wages for whewell and r. jones. the summer was intensely hot, and i believe that the heat and the work in dolcoath had weakened me a good deal. the family was the old clergyman, his wife, his daughter, and finally his son. we lived together very amicably. my brother lodged in a cafã© in the place martroi; the others in different families. i left orlã©ans on sept. 30th for paris. here i attended the institut, and was present at one of ampã¨re's lectures. i arrived at cambridge on oct. 14th. "on oct. 16th whewell mentioned to me that the lucasian professorship would be immediately vacated by turton, and encouraged me to compete for it. shortly afterwards mr higman mentioned the professorship, and joshua king (of queens') spoke on the restriction which prevented college tutors or assistant tutors from holding the office. about this time mr peacock rendered me a very important service. as the emolument of the lucasian professorship was only _â£99_, and that of the assistant tutorship _â£150_, i had determined to withdraw from the candidature. but mr peacock represented to me the advantage of position which would be gained by obtaining the professorship (which i then instantly saw), and i continued to be a candidate. i wrote letters to the heads of colleges (the electors) and canvassed them personally. only dr davy, the master of caius college, at once promised me his vote. dr french, master of jesus college, was a candidate; and several of the heads had promised him their votes. mr babbage, the third candidate, threatened legal proceedings, and dr french withdrew. the course was now open for mr babbage and me. "in the meetings of the philosophical society a new mode of proceeding was introduced this term. to enliven the meetings, private members were requested to give oral lectures. mine was the second, i think, and i took for subject the machinery of the steam engines in the cornish mines, and especially of the pumping engines and pumps. it made an excellent lecture: the subjects were at that time undescribed in books, and unknown to engineers in general out of cornwall. "my college lectures seem to have been, oct. 21st to dec. 14th to 31 junior sophs, dec. 4th to 12th to 12 senior sophs. i assisted at the examinations of the questionists. i had no private pupils. on nov. 26th i communicated to the cambridge philosophical society a paper on the theory of pendulums, balances, and escapements: and i find applications of babbage's symbolism to an escapement which i proposed. i have various investigations about the earth, supposed to project at middle latitudes above the elliptical form. in november an account of the dolcoath failure (by whewell) was given to the royal society. "at length on dec. 7th, 1826, the election to the lucasian professorship took place: i was elected (i think unanimously) and admitted. i believe that this gave great satisfaction to the university in general. my uncle, arthur biddell, was in cambridge on that evening, and was the first of my friends who heard of it. on the same page of my quires on which this is mentioned, there is a great list of apparatus to be constructed for lucasian lectures, notes of experiments with atwood's machine, &c. in december, correspondence with dollond about prisms. i immediately issued a printed notice that i would give professorial lectures in the next term. "on dec. 13th i have a letter from mr smith informing me of the dangerous illness (fever) which had attacked nearly every member of his family, richarda worst of all. on dec. 23rd i went to bury. the affairs with cropley had been settled by the sale of his property under execution, and my father did not lose much of his debt. but he had declined much in body and mind, and now had strange hallucinations. "the commencement of 1827 found me in a better position (not in money but in prospects) than i had before stood in: yet it was far from satisfactory. i had resigned my assistant tutorship of _â£150_ per annum together with the prospect of succeeding to a tutorship, and gained only the lucasian professorship of _â£99_ per annum. i had a great aversion to entering the church: and my lay fellowship would expire in 7 years. my prospects in the law or other professions might have been good if i could have waited: but then i must have been in a state of starvation probably for many years, and marriage would have been out of the question: i much preferred a moderate income in no long time, and i am sure that in this i judged rightly for my happiness. i had now in some measure taken science as my line (though not irrevocably), and i thought it best to work it well, for a time at least, and wait for accidents. "the acceptance of the lucasian professorship prevented me from being pressed by sedgwick (who was proctor this year) to take the office of moderator: which was a great relief to me. as lucasian professor i was ipso facto member of the board of longitude. a stipend of _â£100_ a year was attached to this, on condition of attending four meetings: but i had good reason (from intimations by south and other persons in london) for believing that this would not last long. the fortnightly notices of the meetings of the board were given on jan. 18th, mar. 22nd, may 24th and oct. 18th. "on jan. 2nd, 1827, i came from london to bury. i found my father in a very declining state (the painful rheumatism of some years had changed to ulcerations of the legs, and he was otherwise helpless and had distressing hallucinations). on jan. 8th i walked to cambridge. at both places i was occupied in preparations for the smith's prize examination and for lectures (for the latter i obtained at bury gaol some numerical results about tread-mills). "of the smith's prize i was officially an examiner: and i determined to begin with---what had never been done before--making the examination public, by printing the papers of questions. the prize is the highest mathematical honour in the university: the competitors are incepting bachelors of arts after the examination for that degree. my day of examination (apparently) was jan. 21st. the candidates were turner, cankrein, cleasby, and mr gordon. the first three had been my private pupils: mr gordon was a fellow-commoner of st peter's college, and had just passed the b.a. examination as senior wrangler, turner being second. my situation as examiner was rather a delicate one, and the more so as, when i came to examine the papers of answers, turner appeared distinctly the first. late at night i carried the papers to whewell's rooms, and he on inspection agreed with me. the other examiners (professors lax and woodhouse, lowndean and plumian professors) generally supported me: and turner had the honour of first smith's prize. "on jan. 30th my mother wrote, asking if i could see cropley in london, where he was imprisoned for contempt of chancery. i attended the meeting of the board of longitude on feb. 1st, and afterwards visited cropley in the fleet prison. he died there, some time later. it was by the sale of his effects under execution that my father's debt was paid. "on feb. 15th i communicated to the royal society a paper on the correction of the solar tables from south's observations. i believe that i had alluded to this at the february meeting of the board of longitude, and that in consequence mr pond, the astronomer royal, had been requested to prepare the errors of the sun's place from the greenwich observations: which were supplied some months later. with the exception of south's solar errors, and some investigations about dipping-needles, i do not find anything going on but matters connected with my approaching lectures. there are bridges, trusses, and other mechanical matters, theoretical and practical, without end. several tradesmen in cambridge and london were well employed. on feb. 13th i have a letter from cubitt about groins: i remember studying those of the custom-house and other places. on feb. 20th my syllabus of lectures was finished: this in subsequent years was greatly improved. i applied to the royal society for the loan of huyghens's object-glass, but they declined to lend it. about this time i find observations of the spectrum of sirius. "there had been no lectures on experimental philosophy (mechanics, hydrostatics, optics) for many years. the university in general, i believe, looked with great satisfaction to my vigorous beginning: still there was considerable difficulty about it. there was no understood term for the lectures: no understood hour of the day: no understood lecture room. i began this year in the lent term, but in all subsequent years i took the easter term, mainly for the chance of sunlight for the optical experiments, which i soon made important. i could get no room but a private or retiring room (not a regular lecture room) in the buildings at the old botanic garden: in following years i had the room under the university library. the lectures commenced on some day in february 1827: i think that the number who attended them was about 64. i remember very well that the matter which i had prepared as an introductory lecture did not last above half the time that i had expected, but i managed very well to fill up the hour. on another occasion i was so ill-prepared that i had contemplated giving notice that i was unable to complete the hour's lecture, but i saw in the front row some strangers, introduced by some of my regular attendants, very busy in taking notes, and as it was evident that a break-down now would not do, i silently exerted myself to think of something, and made a very good lecture. "on mar. 1st, as official examiner, i received notices from 14 candidates for bell's scholarships, and prepared my paper of questions. i do not remember my day of examination; but i had all the answers to all the examiners' questions in my hands, when on mar. 27th i received notice that my father had died the preceding evening. this stopped my lectures: they were concluded in the next term. i think that i had only mechanics and imperfect optics this term, no hydrostatics; and that the resumed lectures were principally optical. they terminated about may 14th. "with my brother i at once went to bury to attend my father's funeral. he was buried on mar. 31st, 1827, in the churchyard of little whelnetham, on the north side of the church. shortly afterwards i went to london, and on apr. 5th i attended a meeting of the board of longitude, at which herschel produced a paper regarding improvements of the nautical almanac. herschel and i were in fact the leaders of the reforming party in the board of longitude: dr young the secretary resisted change as much as possible. after the meeting i went to cambridge. i find then calculations of achromatic eye-pieces for a very nice model with silk threads of various colours which i made with my own hands for my optical lectures. "on apr. 7th herschel wrote to me that the professorship held by dr brinkley (then appointed bishop of cloyne) at dublin would be vacant, and recommended it to my notice, and sent me some introductions. i reached dublin on apr. 15th, where i was received with great kindness by dr brinkley and dr macdonnell (afterwards provost). i there met the then provost dr bartholomew lloyd, dr lardner, mr hamilton (afterwards sir w. r. hamilton) and others. in a few days i found that they greatly desired to appoint hamilton if possible (they did in fact overcome some difficulties and appoint him in a few months), and that they would not make such an augmentation as would induce me to offer myself as a candidate, and i withdrew. i have always remembered with gratitude dr macdonnell's conduct, in carefully putting me on a fair footing in this matter. i returned by holyhead, and arrived at birmingham on apr. 23rd. while waiting there and looking over some papers relating to the spherical aberration of eye-pieces, in which i had been stopped some time by a geometrical difficulty, i did in the coffee-room of a hotel overcome the difficulty; and this was the foundation of a capital paper on the spherical aberration of eye-pieces. this paper was afterwards presented to the cambridge philosophical society. "about this time a circumstance occurred of a disagreeable nature, which however did not much disconcert me. mr ivory, who had a good many years before made himself favourably known as a mathematician, especially by his acquaintance with laplace's peculiar analysis, had adopted (as not unfrequently happens) some singular hydrostatical theories. in my last paper on the figure of the earth, i had said that i could not receive one of his equations. in the philosophical magazine of may he attacked me for this with great heat. on may 8th i wrote an answer, and i think it soon became known that i was not to be attacked with impunity. "long before this time there had been some proposal about an excursion to the lake district with my sister, and i now arranged to carry it out. on may 23rd i went to bury and on to playford: while there i sketched the cumberland excursion. on june 5th i went to london, i believe to the visitation of the greenwich observatory to which i was invited. i also attended the meeting of the board of longitude. i think it was here that pond's errors of the sun's place in the nautical almanac from greenwich observations were produced. on june 7th i went by coach to rugby, where i met my sister, and we travelled to edensor. we made a number of excursions in derbyshire, and then passed on by penrith to keswick, where we arrived on june 22nd. from keswick we made many excursions in the lake district, visited mr southey and mr wordsworth, descended a coal mine at whitehaven, and returned to edensor by the way of ambleside, kendal, and manchester. with sundry excursions in derbyshire our trip ended, and we returned to cambridge on the 21st july. "during this long vacation i had one private pupil, crawford, the only pupil this year, and the last that i ever had. at this time there is on my papers an infinity of optical investigations: also a plan of an eye-piece with a concave lens to destroy certain aberrations. on aug. 20th i went to woodford to see messrs gilbert's optical works. from aug. 13th i had been preparing for the discussion of the greenwich solar errors, and i had a man at work in my rooms, engaged on the calculation of the errors. i wrote to bouvard at paris for observations of the sun, but he recommended me to wait for the tables which bessel was preparing. i was busy too about my lectures: on sept. 29th i have a set of plans of printing presses from hansard the printer (who in a visit to cambridge had found me making enquiries about them), and i corresponded with messrs gilbert about optical constructions, and with w. and s. jones, eastons, and others about pumps, hydraulic rams, &c. on sept. 25th occurred a very magnificent aurora borealis. "i do not find when the investigation of corrections of solar elements was finished, or when my extracts from burckhardt, connaissance des temps 1816, were made. but these led me to suspect an unknown inequality in the sun's motion. on sept. 27th and 28th i find the first suspicions of an inequality depending on 8 ã� mean longitude of venus--13 ã� mean longitude of earth. the thing appeared so promising that i commenced the investigation of the perturbation related to this term, and continued it (a very laborious work) as fast as i was able, though with various interruptions, which in fact were necessary to keep up my spirits. on oct. 30th i went to london for the board of longitude meeting. here i exhibited the results of my sun investigations, and urged the correction of the elements used in the nautical almanac. dr young objected, and proposed that bouvard should be consulted. professor woodhouse, the plumian professor, was present, and behaved so captiously that some members met afterwards to consider how order could be maintained. i believe it was during this visit to london that i took measures of hammersmith suspension bridge for an intended lecture-model. frequently, but not always, when in london, i resided at the house of mr sheepshanks and his sister miss sheepshanks, 30 woburn place. my quires, at this time, abound with suggestions for lectures and examinations. "on some day about the end of november or beginning of december 1827, when i was walking with mr peacock near the outside gate of the trinity walks, on some mention of woodhouse, the plumian professor, mr peacock said that he was never likely to rise into activity again (or using some expression importing mortal illness). instantly there had passed through my mind the certainty of my succeeding him, the good position in which i stood towards the university, the probability of that position being improved by improved lectures, &c., &c., and by increased reputation from the matters in which i was now engaged, the power of thus commanding an increase of income. i should then have, independent of my fellowship, some competent income, and a house over my head. i was quite aware that some time might elapse, but now for the first time i saw my way clearly. the care of the observatory had been for two or three years attached to the plumian professorship. a grace was immediately prepared, entrusting the temporary care of the observatory to dr french, to me, mr catton, mr sheepshanks, and mr king (afterwards master of queens' college). on dec. 6th i have a note from mr king about going to the observatory. "on dec. 6th my paper on corrections of the elements of the solar tables was presented to the royal society. on dec. 9th, at 1 h. 4 m. a.m. (sunday morning), i arrived at the result of my calculations of the new inequality. i had gone through some fluctuations of feeling. usually the important part of an inequality of this kind depends entirely on the eccentricities of the orbits, but it so happened that from the positions of the axes of the orbits, &c., these terms very nearly destroyed each other. after this came the consideration of inclinations of orbits; and here were sensible terms which were not destroyed. finally i arrived at the result that the inequality would be about 3"; just such a magnitude as was required. i slipped this into whewell's door. this is, to the time of writing (1853), the last improvement of any importance in the solar theory. some little remaining work went on to dec. 14th, and then, being thoroughly tired, i laid by the work for revision at some future time. i however added a postscript to my royal society paper on solar errors, notifying this result. "on dec. 19th i went to bury. while there i heard from whewell that woodhouse was dead. i returned to cambridge and immediately made known that i was a candidate for the now vacant plumian professorship. of miscellaneous scientific business, i find that on oct. 13th professor barlow of woolwich prepared a memorial to the board of longitude concerning his fluid telescope (which i had seen at woodford), which was considered on nov. 1st, and i had some correspondence with him in december. in june and august my trigonometry was printing. "on jan. 5th, 1828, i came from london. it seems that i had been speculating truly 'without book' on perturbations of planetary elements, for on jan. 17th and 18th i wrote a paper on a supposed error of laplace, and just at the end i discovered that he was quite right: i folded up the paper and marked it 'a lesson.' i set two papers of questions for smith's prizes (there being a deficiency of one examiner, viz. the plumian professor). "before the beginning of 1828 whewell and i had determined on repeating the dolcoath experiments. on jan. 8th i have a letter from davies gilbert (then president of the royal society) congratulating me upon the solar theory, and alluding to our intended summer's visit to cornwall. we had somehow applied to the board of longitude for pendulums, but dr young wished to delay them, having with capt. basil hall concocted a scheme for making lieut. foster do all the work: whewell and i were indignant at this, and no more was said about it. on jan. 24th dr young, in giving notice of the board of longitude meeting, informs me that the clocks and pendulums are ready. "i had made known that i was a candidate for the plumian professorship, and nobody thought it worth while to oppose me. one person at least (earnshaw) had intended to compete, but he called on me to make certain that i was a candidate, and immediately withdrew. i went on in quality of syndic for the care of the observatory, ingrafting myself into it. but meantime i told everybody that the salary (about _â£300_) was not sufficient for me; and on jan. 20th i drafted a manifesto or application to the university for an increase of salary. the day of election to the professorship was feb. 6th. as i was officially (as lucasian professor) an elector, i was present, and i explained to the electors that i could not undertake the responsibility of the observatory without augmentation of income, and that i requested their express sanction to my application to the university for that purpose. they agreed to this generally, and i was elected. i went to london immediately to attend a meeting of the board of longitude and returned on feb. 8th. on feb. 15th i began my lectures (which, this year, included mechanics, optics, pneumatics, and hydrostatics) in the room below the university library. the number of names was 26. the lectures terminated on mar. 22nd. "on feb. 25th i received from mr pond information on the emoluments at greenwich observatory. i drew up a second manifesto, and on feb. 26th i wrote and signed a formal copy for the plumian electors. on feb. 27th i met them at caius lodge (the master, dr davy, being vice-chancellor). i read my paper, which was approved, and their sanction was given in the form of a request to the vice-chancellor to permit the paper to be printed and circulated. my paper, with this request at the head, was immediately printed, and a copy was sent to every resident m.a. (more than 200 went out in one day). the statement and composition of the paper were generally approved, but the university had never before been taken by storm in such a manner, and there was some commotion about it. i believe that very few persons would have taken the same step. mr sheepshanks wrote to me on mar. 7th, intimating that it was desperate. i had no doubt of success. whewell told me that some people accused me of bad faith, in omitting allusion to the _â£100_ a year received as member of the board of longitude, and to the profits of lectures. i wrote him a note, telling him that i had most certain information of the intention to dissolve the board of longitude (which was done in less than six months), and that by two years' lectures i had gained _â£45_ (the expenses being _â£200_, receipts _â£245_). this letter was sent to the complaining people, and no more was said. by the activity of sheepshanks and the kindness of dr davy the business gradually grew into shape, and on mar. 21st a grace passed the senate for appointing a syndicate to consider of augmentation. sheepshanks was one of the syndicate, and was understood to represent, in some measure, my interests. the progress of the syndicate however was by no means a straightforward one. members of the senate soon began to remark that before giving anything they ought to know the amount of the university revenue, and another syndicate was then appointed to enquire and report upon it. it was more than a year before my syndicate could make their recommendation: however, in fact, i lost nothing by that delay, as i was rising in the estimation of the university. the observatory house was furnished, partly from woodhouse's sale, and partly from new furniture. my mother and sister came to live with me there. on mar. 15th 1828 i began the observatory journal; on mar. 27th i slept at the observatory for the first time, and on apr. 15th i came to reside there permanently, and gave up my college rooms." chapter iv. at cambridge observatory. from his taking charge of the cambridge observatory to his residence at greenwich observatory as astronomer royal. from march 15th 1828 to jan. 1st 1836. 1828 "i attended a meeting of the board of longitude on apr. 3rd. and again on june 4th; this was the last meeting: sheepshanks had previously given me private information of the certainty of its dissolution.--on apr. 4th i visited mr herschel at slough, where one evening i saw saturn with his 20-foot telescope, the best view of it that i have ever had.--in june i attended the greenwich observatory visitation.--before my election (as plumian professor) there are various schemes on my quires for computation of transit corrections, &c. after apr. 15th there are corrections for deficient wires, inequality of pivots, &c. and i began a book of proposed regulations for observations. in this are plans for groups of stars for r.a. (the transit instrument being the only one finished): order of preference of classes of observations: no reductions to be made after dinner, or on sunday: no loose papers: observations to be stopped if reductions are two months in arrear: stars selected for parallax.--the reduction of transits begins on apr. 15th. on may 15th mr pond sent me some moon-transits to aid in determining my longitude.--dr young, in a letter to me of may 7th, enquires whether i will accept a free admission to the royal society, which i declined. on may 9th i was elected to the astronomical society.--towards the end of the year i observed encke's comet: and determined the latitude of the observatory with sheepshanks's repeating circle.--on my papers i find a sketch of an article on the figure of the earth for the encyclopaedia metropolitana. "as early as feb. 23rd i had been in correspondence with t. jones, the instrument-maker, about pendulums for a repetition of the dolcoath experiments. invitations had been received, and everything was arranged with whewell. sheepshanks, my brother, and mr jackson of ipswich (caius coll.) were to go, and we were subsequently joined by sedgwick, and lodge (magdalene coll.). on july 3rd sheepshanks and i started by salisbury, taking sherborne on our way to look at the church, which had alarmed the people by signs of a crack, and arrived at camborne on july 8th. on the 14th we set up the pendulums, and at once commenced observations, our plan being, to have no intermission in the pendulum observations, so that as soon as the arc became too small a fresh series was started. on july 29th we raised the instruments, and sheepshanks, who managed much of the upper operations, both astronomical and of pendulums, mounted the pendulums together in his observatory. we went on with our calculations, and on august 8th, on returning from a visit to john williams at barncoose, we heard that there was a 'run' in dolcoath, that is a sinking of the whole mass of rock where it had been set free by the mine excavations: probably only a few inches, but enough to break the rock much and to stop the pumps. on aug. 10th the calculations of our observations shewed that there was something wrong, and on the 13th i perceived an anomaly in the form of the knife edge of one pendulum, and of its agate planes, and suggested cautions for repeating the observations. we determined at once to repeat them: and as the water was rising in the mine there was no time to be lost. we again sent the instruments down, and made observations on the 16th, 17th and 18th. on the 19th i sent the instruments up, for the water was near our station, and sedgwick, whewell, and i went on a geological expedition to the lizard. on our return we met sheepshanks and the others, and found the results of the last observations unsatisfactory. the results of comparing the pendulums were discordant, and the knife edge of the faulty pendulum had very sensibly altered. we now gave up observations, with the feeling that our time had been totally lost, mainly through the fault of the maker of the pendulum (t. jones). on the 28th we made an expedition to penzance and other places, and arrived at cambridge on the 17th of september. "in the course of the work at dolcoath we made various expeditions as opportunity offered. thus we walked to carn brea and witnessed the wrestling, the common game of the country. on another occasion sedgwick, whewell, and i had a capital geological expedition to trewavas head to examine granite veins. we visited at pendarves and trevince, and made the expedition to the lizard already referred to, and saw many of the sights in the neighbourhood. after visiting penzance on the conclusion of our work we saw cape cornwall (where whewell overturned me in a gig), and returned homewards by way of truro, plymouth (where we saw the watering-place and breakwater: also the dockyard, and descended in one of the working diving-bells), exeter, salisbury, and portsmouth. in returning from camborne in 1826 i lost the principal of our papers. it was an odd thing that, in going through exeter on our way to camborne in 1828, i found them complete at exeter, identified to the custodian by the dropping out of a letter with my address. "on my return to cambridge i was immediately immersed in the work of the observatory. the only instrument then mounted at the observatory was the transit. i had no assistant whatever.--a mr galbraith of edinburgh had questioned something in one of my papers about the figure of the earth. i drew up a rather formal answer to it: whewell saw my draft and drew up a much more pithy one, which i adopted and sent to the philosophical magazine.--for comparing our clocks at the upper and lower stations of dolcoath we had borrowed from the royal observatory, greenwich, six good pocket chronometers: they were still in the care of mr sheepshanks. i arranged with him that they should be sent backwards and forwards a few times for determining the longitude of cambridge observatory. this was done on oct. 21st, 22nd, 23rd: the result was 23â°54, and this has been used to the present time (1853). it evinced an error in the trigonometrical survey, the origin of which was found, i think, afterwards (dr pearson in a letter of dec. 17th spoke of the mistake of a may-pole for a signal-staff). i drew up a paper on this, and gave it to the cambridge philosophical society on nov. 24th. (my only academical paper this year.)--i had several letters from dr young, partly supplying me with calculations that i wanted, partly on reform or extension of the nautical almanac (which dr young resisted as much as possible). he considered me very unfairly treated in the dissolution of the board of longitude: professor lax wished me to join in some effort for its restoration, but i declined. "as my reduction of observations was kept quite close, i now began to think of printing. in regard to the form i determined to adopt a plan totally different from that of any other observations which i had seen. the results were to be the important things: i was desirous of suppressing the separate wires of transits. but upon consulting herschel and other persons they would not agree to it, and i assented to keeping them. i applied to the press syndicate to print the work, and on nov. 10th at the request of t. musgrave (afterwards archbishop of york) i sent a specimen of my ms.: on nov. 11th they granted 250 copies, and the printing soon commenced." 1829 "during a winter holiday at playford i wrote out some investigations about the orbits of comets, and on jan. 23rd 1829 i returned to cambridge. the smith's prize examination soon followed, in which i set a paper of questions as usual. on feb. 18th i made notes on liesganig's geodetic work at the british museum. "i was naturally anxious now about the settlement of my salary and of the observatory establishment. i do not know when the syndicate made their report, but it must have been in the last term of 1828. it recommended that the salary should be annually made up (by grace) to _â£500_: that an assistant should be appointed with the assent of the vice-chancellor and dismissable by the plumian professor: and that a visiting syndicate should be appointed, partly official and partly of persons to be named every year by grace. the grace for adopting this report was to be offered to the senate on feb. 27th. the passing of the grace was exposed to two considerable perils. first, i found out (just in time) that a senior fellow of trinity (g.a. browne) was determined to oppose the whole, on account of the insignificant clause regarding dismissal of assistants, which he regarded as tyrannical. i at once undertook that that clause should be rejected. secondly, by the absurd constitution of the 'caput' at cambridge, a single m.a. had the power of stopping any business whatever, and an m.a. actually came to the senate house with the intention of throwing out all the graces on various business that day presented to the senate. luckily he mistook the hour, and came at 11 instead of 10, and found that all were dispatched. the important parts of the grace passed without any opposition: but i mustered some friends who negatived that part which had alarmed g.a. browne, and it was corrected to his satisfaction by a new grace on mar. 18th. i was now almost set at rest on one of the great objects of my life: but not quite. i did not regard, and i determined not to regard, the addition to my salary as absolutely certain until a payment had been actually made to me: and i carefully abstained, for the present, from taking any steps based upon it. i found for assistant at the observatory an old lieutenant of the royal navy, mr baldrey, who came on mar. 16. "on may 4th i began lectures: there were 32 names. the lectures were improving, especially in the optical part. i do not find note of the day of termination.--i do not know the actual day of publication of my first small volume of cambridge observations, 1828, and of circulation. the date of the preface is apr. 27th 1829. i have letters of approval of it from davies gilbert, rigaud, and lax. the system which i endeavoured to introduce into printed astronomical observations was partially introduced into this volume, and was steadily improved in subsequent volumes. i think that i am justified, by letters and other remarks, in believing that this introduction of an orderly system of exhibition, not merely of observations but of the steps for bringing them to a practical result--quite a novelty in astronomical publications--had a markedly good effect on european astronomy in general.--in feb. and march i have letters from young about the nautical almanac: he was unwilling to make any great change, but glad to receive any small assistance. south, who had been keeping up a series of attacks on young, wrote to me to enquire how i stood in engagements of assistance to young: i replied that i should assist young whenever he asked me, and that i disapproved of south's course.--the date of the first visitation of the (cambridge) observatory must have been near may 11th: i invited south and baily to my house; south and i were very near quarrelling about the treatment of young.--in a few days after dr young died: i applied to lord melville for the superintendence of the nautical almanac: mr croker replied that it devolved legally upon the astronomer royal, and on may 30th pond wrote to ask my assistance when i could give any. on june 6th i was invited to the greenwich visitation, to which i believe i went on the 10th. "i had long desired to see switzerland, and i wished now to see some of the continental observatories. i was therefore glad to arrange with mr lodge, of magdalene college (perhaps 10 years senior to myself), to make a little tour. capt. w.h. smyth and others gave me introductions. i met lodge in london, and we started for calais on july 27th 1829. we visited a number of towns in belgium (at brussels i saw the beginning of the observatory with quetelet), and passed by cologne, frankfort, fribourg, and basle to zurich. thus far we had travelled by diligence or posting: we now procured a guide, and travelled generally on foot. from the 13th to the 31st august we travelled diligently through the well-known mountainous parts of switzerland and arrived at geneva on the 31st august. here i saw m. gautier, m. gambard, and the beginning of the observatory. mr lodge was now compelled to return to cambridge, and i proceeded alone by chambã©ry to turin, where i made the acquaintance of m. plana and saw the observatory. i then made a tour through north italy, looking over the observatories at milan, padua, bologna, and florence. at leghorn i took a passage for marseille in a xebeque, but after sailing for three days the weather proved very unfavourable, and i landed at spezia and proceeded by genoa and the cornici road to marseille. at marseille i saw m. gambart and the observatory, and passed by avignon, lyons, and nevers to orlã©ans, where i visited my old host m. legarde. thence by paris, beauvais, and calais to london and cambridge, where i arrived on the 30th october. i had started with more than _â£140_ and returned with _2s. 6d_. the expedition was in many ways invaluable to me. "on my return i found various letters from scientific men: some approving of my method for the mass of the moon: some approving highly of my printed observations, especially d. gilbert, who informed me that they had produced good effect (i believe at greenwich), and herschel.--on nov. 13th i gave the royal astronomical society a paper about deducing the mass of the moon from observations of venus: on nov. 16th a paper to the cambridge philosophical society on a correction to the length of a ball-pendulum: and on dec. 14th a paper on certain conditions under which perpetual motion is possible.--the engravings for my figure of the earth in the encyclopaedia metropolitana were dispatched at the end of the year. some of the paper (perhaps much) was written after my return from the continent.--i began, but never finished, a paper on the form of the earth supposed to be projecting at middle latitudes. in this i refer to the printed paper which nicollet gave me at paris. i believe that the investigations for my paper in the encyclopaedia metropolitana led me to think the supposition unnecessary.--on nov. 6th i was elected member of the geological society. "on nov. 16th 1829 notice was given of a grace to authorize payment to me of _â£157. 9s. 1d._, in conformity with the regulations adopted on feb. 27th, and on nov. 18th the grace passed the senate. on nov. 19th the vice-chancellor wrote me a note enclosing the cheque. on nov. 23rd (practically the first day on which i could go) i went to london and travelled to edensor, where i arrived on the 26th. here i found richarda smith, proposed to her, and was accepted. i stayed there a few days, and returned to cambridge." 1830 "on jan. 25th 1830 the smith's prize paper was prepared. i was (with my assistant, mr baldrey) vigorously working the transit instrument and its reductions, and gradually forming a course of proceeding which has had a good effect on european astronomy. and i was preparing for my marriage. "on mar. 11th i started with my sister to london, and arrived at edensor on the afternoon of the 14th. on the 17th i started alone for manchester and liverpool. through mr mason, a cotton-spinner at calver, near edensor, i had become acquainted with mr john kennedy of manchester, and i had since 1824 been acquainted with dr traill of liverpool. amongst other things, i saw the works of the manchester and liverpool railway, then advancing and exciting great interest, and saw george stephenson and his son. on mar. 24th i was married to richarda smith by her father in edensor. we stopped at edensor till apr. 1st, and then started in chaises by way of newark and kettering (where we were in danger of being stopped by the snow), and arrived at cambridge on apr. 3rd. "i was now busy in preparing for lectures, especially the part of the optical lectures which related to the theory of interferences and polarization. i think it was now that my wife drew some of my lecture pictures, exhibiting interference phenomena. my lectures began on apr. 26th and finished on may 24th. the number of names was 50. they were considered an excellent course of lectures. "may 9th is the date of my preface to the 1829 observations: all was then printed. apparently i did not go to the visitation of the greenwich observatory this year.--i was at this time pressing tulley, the optician, about an object-glass for the mural circle.--a new edition of my 'tracts' was wanted, and i prepared to add a tract on the undulatory theory of light in its utmost extent. the syndicate of the university press intimated through dr turton that they could not assist me (regarding the book as a second edition). on july 10th i have some negociation about it with deighton the bookseller.--on may 18th i have a note from whewell about a number of crystals of plagiedral quartz, in which he was to observe the crystalline indication, and i the optical phenomena.--the report of the syndicate for visiting the observatory is dated june 18th: it is highly laudatory.--the proctor (barnard of king's college) requested me to name the moderator for the next b.a. examination: i named mr challis. "on june 14th my wife and i went, in company with professor and mrs henslow, to london and oxford; at oxford we were received in christchurch college by dr and mrs buckland. my wife and i then went to bedford to visit capt. and mrs smyth, and returned to cambridge on the 23rd. on july 5th we went on a visit to my mother and uncle at playford. while there i took a drive with my uncle into some parts near the valley of the gipping, in which i thought that the extent of the chalk was inadequately exhibited on greenough's map, and communicated my remarks to buckland. "i find letters from dr robinson and col. colby about determining longitudes of certain observatories by fire signals: i proposed chronometers as preferable. also from herschel, approving of my second volume of observations: and from f. baily, disclaiming the origination of the attack on the old nautical almanac (with which i suppose i had reproached him). on july 30th i received a summons from south to a committee for improving the nautical almanac; and subsequently a letter from baily about schumacher's taking offence at a passage of mine in the cambridge observations, on the comparative merits of ephemerides, which i afterwards explained to his satisfaction. "on aug. 24th my wife and i started for edensor, and after a short stay there proceeded by manchester to cumberland, where we made many excursions. we returned by edensor, and reached cambridge on oct. 6th, bringing my wife's sister susanna on a visit. my mother had determined, as soon as my intention of marriage was known to her, to quit the house, although always (even to her death) entertaining the most friendly feelings and fondness for my wife. it was also judged best by us all that my sister should not reside with us as a settled inhabitant of the house. they fixed themselves therefore at playford in the farm-house of the luck's farm, then in the occupation of my uncle arthur biddell. on oct. 21st i have a letter from my sister saying that they were comfortably settled there. "in this month of october (principally, i believe) i made some capital experiments on quartz, which were treated mathematically in a paper communicated in the next year to the cambridge philosophical society. in some of these my wife assisted me, and also drew pictures.--on nov. 15th the grace for paying me _â£198. 13s. 8d._ to make my income up to _â£500_ passed the senate.--i made three journeys to london to attend committees, one a committee on the nautical almanac, and one a royal society committee about two southern observatories.--on dec. 31st i have a letter from maclear (medical practitioner and astronomer at biggleswade) about occultations.--in this december i had a quartz object-glass by cauchaix mounted by dollond, and presented it to the observatory.--in this december occurred the alarm from agrarian fires. there was a very large fire at coton, about a mile from the observatory. this created the most extraordinary panic that i ever saw. i do not think it is possible, without having witnessed it, to conceive the state of men's minds. the gownsmen were all armed with bludgeons, and put under a rude discipline for a few days." 1831 "on jan. 4th i went with my wife, first to miss sheepshanks in london, at 30, woburn place, and next to the house of my wife's old friend, the rev. john courtney, at sanderstead, near croydon. i came to london on one day to attend a meeting of the new board of visitors of the greenwich observatory. formerly the board of visitors consisted of the council of the royal society with persons invited by them (in which capacity i had often attended). but a reforming party, of which south, babbage, baily and beaufort were prominent members, had induced the admiralty to constitute a new board, of which the plumian professor was a member. mr pond, the astronomer royal, was in a rather feeble state, and south seemed determined to bear him down: sheepshanks and i did our best to support him. (i have various letters from sheepshanks to this purpose.)--on jan. 22nd we returned to cambridge, and i set an examination paper for smith's prizes as usual.--on jan. 30th i have a letter from herschel about improving the arrangement of pond's observations. i believe that much of this zeal arose from the example of the cambridge observations. "on feb. 21st my paper 'on the nature of the light in the two rays of quartz' was communicated to the philosophical society: a capital piece of deductive optics. on mar. 2nd i went to london, i suppose to attend the board of visitors (which met frequently, for the proposed reform of pond's observations, &c.). as i returned on the outside of the coach there occurred to me a very remarkable deduction from my ideas about the rays of quartz, which i soon tried with success, and it is printed as an appendix to the paper above mentioned. on mar. 6th my son george richard was born." miscellaneous matters in the first half of this year are as follows: "faraday sends me a piece of glass for amici (he had sent me a piece before).--on apr. 9th i dispatched the preface of my 1830 observations: this implies that all was printed.--on apr. 18th i began my lectures and finished on may 24th. there were 49 names. a very good series of lectures.--i think it was immediately after this, at the visitation of the cambridge observatory, that f. baily and lieut. stratford were present, and that sheepshanks went to tharfield on the royston downs to fire powder signals to be seen at biggleswade (by maclear) and at bedford (by capt. smyth) as well as by us at cambridge.--on may 14th i received _â£100_ for my article on the figure of the earth from baldwin the publisher of the encyclopaedia metropolitana.--i attended the greenwich visitation on june 3rd.--on june 30th the observatory syndicate made their report: satisfactory. "on july 6th 1831 i started with my wife and infant son for edensor, and went on alone to liverpool. i left for dublin on the day on which the loss of the 'rothsay castle' was telegraphed, and had a bad voyage, which made me ill during my whole absence. after a little stay in dublin i went to armagh to visit dr robinson, and thence to coleraine and the giant's causeway, returning by belfast and dublin to edensor. we returned to cambridge on sept. 9th. "up to this time the observatory was furnished with only one large instrument, namely the 10-foot transit. on feb. 24th of this year i had received from thomas jones (62, charing cross) a sketch of the stone pier for mounting the equatoreal which he was commissioned to make: and the pier was prepared in the spring or summer. on sept. 20th part of the instrument was sent to the observatory; other parts followed, and jones himself came to mount it. on sept. 16th i received simms's assurance that he was hastening the mural circle.--in this autumn i seriously took up the recalculation of my long inequality of venus and the earth, and worked through it independently; thus correcting two errors. on nov. 10th i went to slough, to put my paper in the hands of mr herschel for communication to the royal society. the paper was read on nov. 24th.--this was the year of the first meeting of the british association at york. the next year's meeting was to be at oxford, and on oct. 17th i received from the rev. w. vernon harcourt an invitation to supply a report on astronomy, which i undertook: it employed me much of the winter, and the succeeding spring and summer.--the second edition of my tracts was ready in october. it contained, besides what was in the first edition, the planetary theory, and the undulatory theory of light. the profit was _â£80_.--on nov. 14th i presented to the cambridge philosophical society a paper 'on a remarkable modification of newton's rings': a pretty good paper.--in november the copley medal was awarded to me by the royal society for my advances in optics.--amongst miscellaneous matters i was engaged in correspondence with col. colby and capt. portlock about the irish triangulation and its calculation. also with the admiralty on the form of publication of the greenwich and cape observations." 1832 "in january my examination paper for smith's prizes was prepared as usual.--two matters (in addition to the daily routine of observatory work) occupied me at the beginning of this year. one was the translation of encke's paper in successive numbers of the astronomische nachrichten concerning encke's comet; the university press printed this gratuitously, and i distributed copies, partly by the aid of capt. beaufort.--the other was the report on astronomy for the british association, which required much labour. my reading for it was principally in the university library (possibly some in london), but i borrowed some books from f. baily, and i wrote to capt. beaufort about the possible repetition of lacaille's meridian arc at the cape of good hope. the report appears to have been finished on may 2nd.--at this time the reform bill was under discussion, and one letter written by me (probably at sheepshanks's request) addressed i think to mr drummond, lord althorp's secretary, was read in the house of commons. "optics were not neglected. i have some correspondence with brewster and faraday. on mar. 5th i gave the cambridge philosophical society a paper 'on a new analyzer,' and on mar. 19th one 'on newton's rings between two substances of different refractive powers,' both papers satisfactory to myself.--on the death of mr f. fallows, astronomer at the cape of good hope observatory, the admiralty appointed mr henderson, an edinburgh lawyer, who had done some little things in astronomical calculation. on jan. 10th i discussed with him observations to be made, and drew up his official instructions which were sent on jan. 10th.--on feb. 16th sir james south writes that encke's comet is seen: also that with his 12-inch achromatic, purchased at paris, and which he was preparing to mount equatoreally, he had seen the disk of aldebaran apparently bisected by the moon's limb.--capt. beaufort and d. gilbert write in march about instructions to dunlop, the astronomer at paramatta. i sent a draft to capt. beaufort on apr. 27th. "the preface to my 1831 observations is dated mar. 20th. the distribution of the book would be a few weeks later.--on may 7th i began my lectures: 51 names: i finished on may 29th.--the mounting of the equatoreal was finished some time before the syndicate visitation at the end of may, but jones's charge appeared to be exorbitant: i believe it was paid at last, but it was considered unfair.--on june 2nd i went to london: i presume to the greenwich visitation.--i went to oxford to the meeting of the british association (lodging i think with prof. rigaud at the observatory) on june 16th, and read part of my report on astronomy in the theatre. "on june 26th i started with my wife for the highlands of scotland. after a short stay at edensor, we went by carlisle to glasgow, and through the lake district to inverness. thence by auchnanault to balmacarra, where we were received by mr lillingstone. after an expedition in skye, we returned to balmacarra, and passed on to invermoriston, where we were received by grant of glenmoriston. we then went to fort william and oban, and crossed over to mull, where we were received by maclean of loch buy. we returned to oban and on to edinburgh, where we made a short stay. then to melrose, where we were received by sir d. brewster, and by edensor to cambridge, where we arrived on sept. 17th. "i received (at edinburgh i believe) a letter from arago, writing for the plans of our observing-room shutters.--mr vernon harcourt wrote deprecating the tone of my report on astronomy as related to english astronomers, but i refused to alter a word.--sheepshanks wrote in september in great anxiety about the cambridge circle, for which he thought the pier ought to be raised: i would have no such thing, and arranged it much more conveniently by means of a pit. on oct. 9th simms says that he will come with the circle immediately, and jones on sept. 29th says that he will make some alteration in the equatoreal: thus there was at last a prospect of furnishing the observatory properly.--on oct. 9th, i have encke's thanks for the translation of the comet paper.--one of the desiderata which i had pointed out in my report on astronomy was the determination of the mass of jupiter by elongations of the 4th satellite: and as the equatoreal of the cambridge observatory was on the point of coming into use, i determined to employ it for this purpose. it was necessary for the reduction of the observations that i should prepare tables of the motion of jupiter's 4th satellite in a form applicable to computations of differences of right-ascension. the date of my tables is oct. 3rd, 1832.--in october the observatory syndicate made their report: quite satisfactory. "on oct. 20th sheepshanks wrote asking my assistance in the penny cyclopaedia: i did afterwards write 'gravitation' and 'greenwich.' --capt. beaufort wrote in november to ask my opinion on the preface to an edition of groombridge's catalogue which had been prepared by h. taylor: sheepshanks also wrote; he had objected to it. this was the beginning of an affair which afterwards gave me great labour.--vernon harcourt writes, much offended at some terms which i had used in reference to an office in the british association. "the equatoreal mounting which troughton and simms had been preparing for sir james south's large telescope had not entirely succeeded. i have various letters at this time from sheepshanks and simms, relating to the disposition which sir james south shewed to resist every claim till compelled by law to pay it.--a general election of members of parliament was now coming on: mr lubbock was candidate for the university. on nov. 27th i had a letter from sedgwick requesting me to write a letter in the newspapers in favour of lubbock; which i did. on dec. 7th i have notice of the county voting at newmarket on dec. 18th and 19th: i walked there to vote for townley; he lost the election by two or three votes in several thousands. "the mural circle was now nearly ready in all respects, and it was known that another assistant would be required. mr richardson (one of the assistants of greenwich observatory) and mr simms recommended to me mr glaisher, who was soon after appointed, and subsequently became an assistant at greenwich.--on dec. 24th i have a letter from bessel (the first i believe). i think that i had written to him about a general reduction of the greenwich planetary observations, using his tabulae regiomontanae as basis, and that this was his reply approving of it." 1833 "on jan. 4th 1833 my daughter elizabeth was born.--i prepared an examination paper for smith's prizes as usual.--on jan. 5th i received notice from simms that he had received payment (_â£1050_) for the mural circle from the vice-chancellor. about this time the circle was completely made serviceable, and i (with mr glaisher as assistant) immediately began its use. a puzzling apparent defect in the circle (exhibiting itself by the discordance of zenith points obtained by reflection observations on opposite sides of the zenith) shewed itself very early. on feb. 4th i have letters about it from sheepshanks and simms.--on jan. 17th i received notice from f. baily that the astronomical society had awarded me their medal for my long inequality of venus and the earth: on feb. 7th i went to london, i suppose to receive the medal.--i also inspected sir j. south's telescope, then becoming a matter of litigation, and visited mr herschel at slough: on feb. 12th i wrote to sir j. south about the support of the instrument, hoping to remove one of the difficulties in the litigation; but it produced no effect.--herschel wrote to me, from poisson, that pontã©coulant had verified my long inequality. "mar. 12th is the date of the preface to my 1832 volume of observations: it was of course distributed a few weeks later.--in my report on astronomy i had indicated the mass of jupiter as a subject requiring fresh investigation. during the last winter i had well employed the equatoreal in observing elongations in r.a. of the 4th satellite. to make these available it was necessary to work up the theory carefully, in which i discovered some remarkable errors of laplace. some of these, for verification, i submitted to mr lubbock, who entirely agreed with me. the date of my first calculations of the mass of jupiter is mar. 1st: and shortly after that i gave an oral account of them to the cambridge philosophical society. the date of my paper for the astronomical society is april 12th. the result of my investigations (which was subsequently confirmed by bessel) entirely removed the difficulty among astronomers; and the mass which i obtained has ever since been received as the true one. "on apr. 9th my wife's two sisters, elizabeth and georgiana smith, came to stay with me.--on apr. 22nd i began lectures, and finished on may 21st: there were 54 names. during the course of the lectures i communicated a paper to the philosophical society 'on the calculation of newton's experiments on diffraction.'--i went to london on the visitation of the greenwich observatory: the dinner had been much restricted, but was now made more open.--it had been arranged that the meeting of the british association was to be held this year at cambridge. i invited sir david brewster and mr herschel to lodge at the observatory. the meeting lasted from june 24th to 30th. we gave one dinner, but had a breakfast party every day. i did not enter much into the scientific business of the meeting, except that i brought before the committee the expediency of reducing the greenwich planetary observations from 1750. they agreed to represent it to the government, and a deputation was appointed (i among them) who were received by lord althorp on july 25th. on aug. 3rd herschel announced to me that _â£500_ was granted. "on aug. 7th i started with my wife for edensor. at leicester we met sedgwick and whewell: my wife went on to edensor, and i joined sedgwick and whewell in a geological expedition to mount sorrel and various parts of charnwood forest. we were received by mr allsop of woodlands, who proved an estimable acquaintance. this lasted four or five days, and we then went on to edensor.--on aug. 15th herschel wrote to me, communicating an offer of the duke of northumberland to present to the cambridge observatory an object-glass of about 12 inches aperture by cauchaix. i wrote therefore to the duke, accepting generally. the duke wrote to me from buxton on aug. 23rd (his letter, such was the wretched arrangement of postage, reaching bakewell and edensor on the 25th) and on the 26th i drove before breakfast to buxton and had an interview with him. on sept. 1st the duke wrote, authorizing me to mount the telescope entirely, and he subsequently approved of cauchaix's terms: there was much correspondence, but on dec. 28th i instructed cauchaix how to send the telescope.--on our return we paid a visit to dr davy, master of caius college, at heacham, and reached cambridge on oct. 8th. "groombridge's catalogue, of which the editing was formally entrusted to mr henry taylor (son of taylor the first-assistant of the greenwich observatory), had been in some measure referred to sheepshanks: and he, in investigating the work, found reason for thinking the whole discreditable. about may he first wrote to me on his rising quarrel with h. taylor, but on sept. 7th he found things coming to a crisis, and denounced the whole. capt. beaufort the hydrographer (in whose office this matter rested) begged me with baily to decide upon it. we did not at first quite agree upon the terms of investigation &c., but after a time all was settled, and on oct. 4th the admiralty formally applied, and i formally accepted. little or nothing had been done by mr baily and myself, when my work was interrupted by illness. "sheepshanks had thought that something might be done to advance the interests of myself or the observatory by the favour of lord brougham (then lord chancellor), and had urged me to write an article in the penny cyclopaedia, in which lord brougham took great interest. i chose the subject 'gravitation,' and as i think wrote a good deal of it in this autumn: when it was interrupted by my illness. "on dec. 9th 1833, having at first intended to attend the meeting of the philosophical society and then having changed my mind, i was engaged in the evening on the formulae for effects of small errors on the computation of the solar eclipse of 1833. a dizziness in my head came on. i left off work, became worse, and went to bed, and in the night was in high fever with a fierce attack of scarlet fever. my wife was also attacked but very slightly. the first day of quitting my bedroom was dec. 31st. somewhere about the time of my illness my wife's sister, susanna smith, who was much reduced in the summer, died of consumption. "miscellaneous notes in 1833 are as follows: henderson (at the cape) could not endure it much longer, and on oct. 14th stratford writes that maclear had just sailed to take his place: henderson is candidate for the edinburgh observatory.--stratford writes on dec. 2nd that the madras observations have come to england, the first whose arrangement imitates mine.--on nov. 3rd herschel, just going to the cape, entrusted to me the revisal of some proof sheets, if necessary: however it was never needed.--in november i sat for my portrait to a painter named purdon (i think): he came to the house and made a good likeness. a pencil portrait was taken for a print-seller (mason) in cambridge: it was begun before my illness and finished after it.--i applied through sheepshanks for a copy of maskelyne's observations, to be used in the reduction of the planetary observations: and on dec. 24th (from my bedroom) i applied through prof. rigaud to the delegates of the clarendon press for a copy of bradley's observations for the same. the latter request was refused. in october i applied to the syndics of the university press for printed forms for these reductions: the syndics agreed to grant me 12,000 copies." 1834 "on jan. 11th 1834 i went with my wife to london for the recruiting of my strength. we stayed at the house of our friend miss sheepshanks, and returned on feb. 13th.--i drew up a paper of questions for smith's prizes, but left the whole trouble of examination and adjudication to professor miller, who at my request acted for me.--while i was in london i began to look at the papers relating to groombridge's catalogue: and i believe that it was while in london that i agreed with mr baily on a report condemnatory of h. taylor's edition, and sent the report to the admiralty. the admiralty asked for further advice, and on feb. 28th i replied, undertaking to put the catalogue in order. on mar. 17th capt. beaufort sent me all the papers. some time however elapsed before i could proceed with it. "there was in this spring a furious discussion about the admission of dissenters into the university: i took the liberal side. on apr. 30th there was a letter of mine in the cambridge newspaper.--on apr. 14th i began lectures, and finished on may 20th: there were 87 names.--my 'gravitation' was either finished or so nearly finished that on jan. 24th i had some conversation with knight the publisher about printing it. it was printed in the spring, and on apr. 27th sheepshanks sent a copy of it to lord brougham. i received from knight _â£83. 17s. 1d._ for this paper.--on may 10th i went to london, i believe to attend one of the soirã©es which the duke of sussex gave as president of the royal society. the duke invited me to breakfast privately with him the next morning. he then spoke to me, on the part of the government, about my taking the office of astronomer royal. on may 19th i wrote him a semi-official letter, to which reference was made in subsequent correspondence on that subject. "on may 12th my son arthur was born.--in june the observatory syndicate made a satisfied report.--on june 7th i went to the greenwich visitation, and again on june 14th i went to london, i believe for the purpose of trying the mounting of south's telescope, as it had been strengthened by mr simms by sheepshanks's suggestions. i was subsequently in correspondence with sheepshanks on the subject of the arbitration on south's telescope, and my giving evidence on it. on july 29th, as i was shortly going away, i wrote him a report on the telescope, to be used in case of my absence. the award, which was given in december, was entirely in favour of simms.--on july 23rd i went out, i think to my brother's marriage at ixworth in suffolk.--on aug. 1st i started for edensor and cumberland, with my wife, sister, and three children: georgiana smith joined us at edensor. we went by otley, harrogate, ripon, and stanmoor to keswick, from whence we made many excursions. on aug. 11th i went with whewell to the clouds on skiddaw, to try hygrometers. mr baily called on his way to the british association at edinburgh. on sept. 10th we transferred our quarters to ambleside, and after various excursions we returned to edensor by skipton and bolton. on sept. 19th i went to doncaster and finningley park to see mr beaumont's observatory. on sept. 25th we posted in one day from edensor to cambridge. "on aug. 25th mr spring rice (lord monteagle) wrote to me to enquire whether i would accept the office of astronomer royal if it were vacant. i replied (from keswick) on aug. 30th, expressing my general willingness, stipulating for my freedom of vote, &c., and referring to my letter to the duke of sussex. on oct. 8th lord auckland, first lord of the admiralty, wrote: and on oct. 10th i provisionally accepted the office. on oct. 30th i wrote to ask for leave to give a course of lectures at cambridge in case that my successor at cambridge should find difficulty in doing it in the first year: and to this lord auckland assented on oct. 31st. all this arrangement was for a time upset by the change of ministry which shortly followed. "amongst miscellaneous matters, in march i had some correspondence with the duke of northumberland about the cauchaix telescope. in august i had to announce to him that the flint-lens had been a little shattered in cauchaix's shop and required regrinding: finally on dec. 17th i announced its arrival at cambridge.--in the planetary reductions, i find that i employed one computer (glaisher) for 34 weeks.--in november the lalande medal was awarded to me by the french institut, and mr pentland conveyed it to me in december.--on march 14th i gave the cambridge philosophical society a paper, 'continuation of researches into the value of jupiter's mass.' on apr. 14th, 'on the latitude of cambridge observatory.' on june 13th, 'on the position of the ecliptic,' and 'on the solar eclipse of 1833,' to the royal astronomical society. on nov. 24th, 'on computing the diffraction of an object glass,' to the cambridge society. and on dec. 3rd, 'on the calculation of perturbations,' to the nautical almanac: this paper was written at keswick between aug. 22nd and 29th.--i also furnished mr sheepshanks with investigations regarding the form of the pivots of the cape circle." 1835 "on jan. 9th 1835 i was elected correspondent of the french academy; and on jan. 26th mr pentland sent me _â£12. 6s._, the balance of the proceeds of the lalande medal fund.--i prepared my paper for smith's prizes, and joined in the examination as usual. "there had been a very sudden change of administration, and sir r. peel was now prime minister as first lord of the treasury, and lord lyndhurst was lord chancellor. on jan. 19th i wrote to lord lyndhurst, asking him for a suffolk living for my brother william, which he declined to give, though he remembered my application some years later. whether my application led to the favour which i shortly received from the government, i do not know. but, in dining with the duke of sussex in the last year, i had been introduced to sir r. peel, and he had conversed with me a long time, and appeared to have heard favourably of me. on feb. 17th he wrote to me an autograph letter offering a pension of _â£300_ per annum, with no terms of any kind, and allowing it to be settled if i should think fit on my wife. i wrote on feb. 18th accepting it for my wife. in a few days the matter went through the formal steps, and mr whewell and mr sheepshanks were nominated trustees for my wife. the subject came before parliament, by the whig party vindicating their own propriety in having offered me the office of astronomer royal in the preceding year; and spring rice's letter then written to me was published in the times, &c." * * * * * the correspondence relating to the pension above-mentioned is given below, and appears to be of interest, both as conveying in very felicitous terms the opinion of a very eminent statesman on the general subject of such pensions, and as a most convincing proof of the lofty position in science which the subject of this memoir had then attained. whitehall gardens, _feb. 17 1835_. sir, you probably are aware that in a resolution voted by the house of commons in the last session of parliament, an opinion was expressed, that pensions on the civil list, ought not thereafter to be granted by the crown excepting for the satisfaction of certain public claims, among which those resting on scientific or literary eminence were especially mentioned. i trust that no such resolution would have been necessary to induce me as minister of the crown fully to recognize the justice of such claims, but i refer to the resolution, as removing every impediment to a communication of the nature of that which i am about to make to you. in acting upon the principle of the resolution in so far as the claims of science are concerned, my _first_ address is made to you, and made directly, and without previous communication with any other person, because it is dictated exclusively by public considerations, and because there can be no advantage in or any motive for indirect communication. i consider you to have the first claim on the royal favour which eminence in those high pursuits to which your life is devoted, can give, and i fear that the emoluments attached to your appointment in the university of cambridge are hardly sufficient to relieve you from anxiety as to the future on account of those in whose welfare you are deeply interested. the state of the civil list would enable me to advise the king to grant a pension of three hundred pounds per annum, and if the offer be acceptable to you the pension shall be granted either to mrs airy or yourself as you may prefer. i beg you distinctly to understand that your acquiescence in this proposal, will impose upon you no obligation personal or political in the slightest degree. i make it solely upon public grounds, and i ask you, by the acceptance of it, to permit the king to give some slight encouragement to science, by proving to those who may be disposed to follow your bright example, that devotion to the highest branches of mathematical and astronomical knowledge shall not necessarily involve them in constant solicitude as to the future condition of those, for whom the application of the same talents to more lucrative pursuits would have ensured an ample provision. i have the honor to be, sir, with true respect and esteem, your faithful servant, robert peel. _mr professor airy, &c., &c., cambridge_. observatory, cambridge, _1835, feb. 18_. sir, i have the honor to acknowledge your letter of the 17th acquainting me with your intention of advising the king to grant a pension of _â£300_ per annum from the civil list to me or mrs airy. i trust you will believe that i am sensible of the flattering terms in which this offer is made, and deeply grateful for the considerate manner in which the principal arrangement is left to my choice, as well as for the freedom from engagement in which your offer leaves me. i beg to state that i most willingly accept the offer. i should prefer that the pension be settled on mrs airy (by which i understand that in case of her surviving me the pension would be continued to her during her life, or in the contrary event would cease with her life). i wish that i may have the good fortune to prove to the world that i do not accept this offer without an implied engagement on my part. i beg leave again to thank you for your attention, and to assure you that the form in which it is conveyed makes it doubly acceptable. with sincere respect i have the honor to be, sir, your very faithful servant, g.b. airy. _the right hon. sir robert peel, bart., first lord of the treasury, &c., &c._ whitehall, _feb. 19th 1835_. sir, i will give immediate directions for the preparation of the warrant settling the pension on mrs airy--the effect of which will be, as you suppose, to grant the pension to her for her life. i assure you i never gave an official order, which was accompanied with more satisfaction to myself than this. i have the honor to be, sir. your faithful servant, robert peel. _mr professor airy, &c., &c., cambridge_. * * * * * "on march 18th 1835 i started (meeting sheepshanks at kingstown) for ireland. we visited dublin observatory, and then went direct to markree near sligo, to see mr cooper's telescope (our principal object). we passed on our return by enniskillen and ballyjamesduff, where my former pupil p. morton was living, and returned on apr. 3rd.--on apr. 20th i was elected to the royal society, edinburgh.--apr. 22nd my wife wrote me from edensor that her sister florence was very ill: she died shortly after.--on may 4th i began lectures and finished on may 29th: there were 58 names.--my former pupil guest asks my interest for the recordership of birmingham.--in june was circulated the syndicate report on the observatory.--the date of the preface to the 1834 observations is june 16th. "the ministry had been again changed in the spring, and the whigs were again in power. on june 11th lord auckland, who was again first lord of the admiralty (as last year), again wrote to me to offer me the office of astronomer royal, or to request my suggestions on the filling up of the office. on june 15th i wrote my first reply, and on june 17th wrote to accept it. on june 18th lord auckland acknowledges, and on june 22nd the king approved. lord auckland appointed to see me on friday, june 23rd, but i was unwell. i had various correspondence with lord auckland, principally about buildings, and had an appointment with him for august 13th. as lord auckland was just quitting office, to go to india, i was introduced to mr charles wood, the secretary of the admiralty, with whom principally the subsequent business was transacted. at this meeting lord auckland and mr wood expressed their feeling, that the observatory had fallen into such a state of disrepute that the whole establishment ought to be cleared out. i represented that i could make it efficient with a good first assistant; and the other assistants were kept. but the establishment was in a queer state. the royal warrant under the sign manual was sent on august 11th. it was understood that my occupation of office would commence on october 1st, but repairs and alterations of buildings would make it impossible for me to reside at greenwich before the end of the year. on oct. 1st i went to the observatory, and entered formally upon the office (though not residing for some time). oct 7th is the date of my official instructions. "i had made it a condition of accepting the office that the then first assistant should be removed, and accordingly i had the charge of seeking another. i determined to have a man who had taken a respectable cambridge degree. i made enquiry first of mr bowstead (brother to the bishop) and mr steventon: at length, consulting mr hopkins (a well-known private tutor at cambridge), he recommended to me mr robert main, of queens' college, with whom i corresponded in the month (principally) of august, and whom on august 30th i nominated to the admiralty. on oct. 21st f.w. simms, one of the assistants (who apparently had hoped for the office of first assistant, for which he was quite incompetent) resigned; and on dec. 4th i appointed in his place mr james glaisher, who had been at cambridge from the beginning of 1833, and on dec. 10th the admiralty approved. "during this quarter of a year i was residing at cambridge observatory, visiting greenwich once a week (at least for some time), the immediate superintendence of the observatory being placed with mr main. i was however engaged in reforming the system of the greenwich observatory, and prepared and printed 30 skeleton forms for reductions of observations and other business. on dec. 14th i resigned my professorship to the vice-chancellor. but i continued the reduction of the observations, so that not a single figure was left to my successor: the last observations were those of halley's comet. the preface to my 1835 cambridge observations is dated aug. 22nd, 1836. "in regard to the northumberland telescope, i had for some time been speculating on plans of mounting and enclosing the instrument, and had corresponded with simms, a. biddell, cubitt, and others on the subject. on apr. 24th tulley the younger was endeavouring to adjust the object-glass. on may 31st i plainly asked the duke of northumberland whether he would defray the expense of the mounting and building. on june 4th he assented, and money was placed at a banker's to my order. i then proceeded in earnest: in the autumn the building was erected, and the dome was covered before the depth of winter. i continued in 1836 to superintend the mounting of the instrument. "in regard to the planetary reductions: to july 11th j. glaisher had been employed 27 weeks, and from july 11th to jan. 16th, 1836, 25 weeks. mr spring rice, when chancellor of the exchequer, had promised money, but no official minute had been made, and no money had been granted. on aug. 21st i applied to mr baring (secretary of the treasury). after another letter he answered on oct. 15th that he found no official minute. after writing to vernon harcourt and to spring rice, the matter was arranged: my outlay was refunded, and another sum granted.--in regard to groombridge's observations, i find that on dec. 16th certain trial reductions had been made under my direction by j. glaisher.--i had attempted some optical experiments in the summer, especially on the polarization of sky-light; but had been too busy with the observatory to continue them. "in august my wife was in a critical state of health.--in december i received information regarding merchant ships' chronometers, for which i had applied to mr charles parker of liverpool.--on dec. 8th mr spring rice and lord john russell offered me knighthood, but i declined it.--on july 23rd i went into suffolk with my wife's sisters elizabeth and georgiana, and returned on august 3rd: this was all the holiday that i got in this year.--on the 14th of august i saw mr taylor, the admiralty civil architect in london, and the extension of buildings at greenwich observatory was arranged.--i made various journeys to greenwich, and on dec. 17th, having sent off our furniture, we all quitted the cambridge observatory, and stayed for some days at the house of miss sheepshanks. "thus ended a busy and anxious year." * * * * * with reference to the offer of knighthood above-mentioned, airy's reply is characteristic, and the short correspondence relating to it is therefore inserted.--the offer itself is an additional proof of the high estimation in which he stood at this time. downing street, _dec. 8th 1835_. my dear sir, i have been in communication with my colleague lord john russell which has made me feel rather anxious to have the pleasure of seeing you, but on second thoughts it has occurred to me that the subject of my communication would render it more satisfactory to you to receive a letter than to pay a visit. in testimony of the respect which is felt for your character and acquirements, there would be every disposition to recommend you to his majesty to receive the distinction of knighthood. i am quite aware that to you individually this may be a matter of small concern, but to the scientific world in general it will not be indifferent, and to foreign countries it will mark the consideration felt for you personally as well as for the position which you occupy among your learned contemporaries. from a knowledge of the respect and esteem which i feel for you lord john russell has wished that the communication should be made through me rather than through any person who had not the pleasure of your acquaintance. pray let me hear from you and believe me my dear sir, with compliments to mrs airy, very truly yours, t. spring rice. p.s.--it may be right to add that when a title of honor is conferred on grounds like those which apply to your case, no fees or charges of any kind would be payable. observatory, cambridge, _1835, dec. 10th_. my dear sir, i beg to acknowledge your letter of the 8th, which i have received at this place, conveying to me an intimation of the wish of his majesty's ministers to recommend me to the king for the honor of knighthood. i beg to assure you that i am most sensible to the liberality which i have experienced from the government in other as well as in pecuniary matters, and that i am very highly gratified by the consideration (undeserved by me, i fear) which they have displayed in the present instance. and if i now request permission to decline the honor offered to me, i trust i may make it fully understood that it is not because i value it lightly or because i am not anxious to receive honors from such a source. the unalterable custom of this country has attached a certain degree of light consideration to titles of honor which are not supported by considerable fortune; or at least, it calls for the display of such an establishment as may not be conveniently supported by even a comfortable income. the provision attached to my official situation, and the liberality of the king towards one of the members of my family, have placed me in a position of great comfort. these circumstances however have bound me to consider myself as the devoted servant of the country, and to debar myself from efforts to increase my fortune which might otherwise have been open to me. i do not look forward therefore to any material increase of income, and that which i enjoy at present is hardly sufficient, in my opinion, to support respectably the honor which you and lord john russell have proposed to confer upon me. for this reason only i beg leave most respectfully to decline the honor of knighthood at the present time. i have only to add that my services will always be at the command of the government in any scientific subject in which i can be of the smallest use. i am, my dear sir, your very faithful servant, g.b. airy. _the right honorable t. spring rice_. * * * * * "in brief revision of the years from 1827 to 1835 i may confine myself to the two principal subjects--my professorial lectures, and my conduct of the cambridge observatory. "the lectures as begun in 1827 included ordinary mechanics, ordinary hydrostatics and pneumatics (i think that i did not touch, or touched very lightly, on the subjects connected with the hydraulic ram), and ordinary optics (with a very few words on polarization and depolarization). in 1828 the two first were generally improved, and for the third (optics) i introduced a few words on circular polarization. i believe that it was in 1829 that i made an addition to the syllabus with a small engraving, shewing the interference of light in the best practical experiment (that of the flat prism); and i went thoroughly into the main points of the undulatory theory, interference, diffraction, &c. in 1830 i believe i went (in addition to what is mentioned above) into polarization and depolarization of all kinds. my best lecture diagrams were drawn and painted by my wife. the lectures were universally pronounced to be valuable. the subjects underwent no material change in 1831, 2, 3, 4, 5; and i believe it was a matter of sincere regret to many persons that my removal to greenwich terminated the series. each lecture nominally occupied an hour. but i always encouraged students to stop and talk with me; and this supplement was usually considered a valuable part of the lecture. practically the lecture, on most days, occupied two hours. i enjoyed the lectures much: yet i felt that the labour (in addition to other work) made an impression on my strength, and i became at length desirous of terminating them. "the observatory, when i took charge of it, had only one instrument--the transit-instrument the principles however which i laid down for my own direction were adapted to the expected complete equipment, planets (totally neglected at greenwich) were to be observed. observations were to be reduced completely, and the reductions were to be exhibited in an orderly way: this was a novelty in astronomy. i considered it so important that i actually proposed to omit in my publication the original observations, but was dissuaded by herschel and others. i sometimes suspended, observations for a short time, in order to obtain leisure for; the reductions. i had at first no intention of correcting the places of the fundamental stars as settled at greenwich. but i found myself compelled to do so, because they were not sufficiently accurate; and then i took the course of observing and reducing as an independent observer, without reference to any other observatory. i introduced the principle of not correcting instrumental errors, but measuring them and applying numerical corrections. i determined my longitude by chronometers, and my latitude by a repeating circle borrowed from mr sheepshanks, which i used so well that the result; was only half a second in error. the form of my reductions in the published volume for 1828 is rather irregular, but the matter is good: it soon attracted attention. in 1829 the process was much the same: i had an assistant, mr baldrey. in 1830 still the same, with the additions:--that i formally gave the corrections of relative right-ascension of fundamental stars (without alteration of equinox, which i had not the means of obtaining) to be used in the year 1831; and that i reduced completely the observed occultations (with a small error, subsequently corrected). in 1831 the system of correction of broken transits was improved: the errors of assumed r.a. of fundamental stars were exhibited: mean solar time was obtained from sidereal time by time of transit of [symbol: aries] (computed by myself): the method of computing occultations was improved. in 1832 the small equatoreal was erected, and was soon employed in observations of the elongation of the 4th satellite of jupiter for determining the mass of jupiter. the mural circle was erected at the end of the year, but not used. the calculation of r.a. of fundamental stars was made homogeneously with the others: separate results of all were included in ledgers: a star-catalogue was formed: all as to the present time (1871). with the equatoreal the difference of n.p.d. of mars and stars was observed. "with the beginning of 1833 the mural circle was established at work, a second assistant (mr glaisher) was appointed, and the observatory might be considered complete. i made experiments on the graduations of the circle. i detected and was annoyed by the r--d. i determined the latitude. i exhibited the separate results for n.p.d. of stars in ledger, and their means in catalogue. i investigated from my observations the place of equinox and the obliquity of the ecliptic. i made another series of observations of jupiter's 4th satellite, for the mass of jupiter. i observed the solar eclipse with the equatoreal, by a method then first introduced, which i have since used several times at cambridge and greenwich with excellent effect. the moon and the planets were usually observed till near two in the morning. correction for defective illumination applied when necessary. the volume is very complete, the only deficiency being in the observation of moon and planets through the severe morning hours. in 1834 the only novelties are--examination of the graduations of the declination circle of the equatoreal (excessively bad): observations of a spot on jupiter for rotation, and of mars and stars. in 1835 (including january 1836) there is a more complete examination of the equatoreal graduations: parallax and refraction for equatoreal observations: a spot on jupiter: a series of observations on jupiter's 4th satellite for the mass of jupiter: mars and stars: halley's comet (the best series of observations which could be made in the season): and a short series of meteorological observations, on a plan suggested by sir john herschel then at the cape of good hope. "i cannot tell precisely in which year i introduced the following useful custom. towards the end of each year i procured a pocket-book for the following year with a space for every day, and carefully examining all the sources of elements of observations, and determining the observations to be made every day, i inserted them in the pocket-book. this system gave wonderful steadiness to the plan of observations for the next year. the system has been maintained in great perfection at the observatory of greenwich. (the first of these pocket-books which prof. adams has found is that for 1833.) printed skeleton forms were introduced for all calculations from 1828. in the greenwich observatory library there is a collection, i believe complete, of printed papers commencing with my manifesto, and containing all syndicate reports except for 1833 (when perhaps there was none). it seems from these that my first written report on observations, &c., was on may 30th, 1834. the first syndicate report is on may 25th, 1829." * * * * * a few remarks on airy's private life and friends during his residence at cambridge observatory may be here appropriately inserted. amid the laborious occupations recorded in the foregoing pages, his social life and surroundings appear to have been most pleasant and congenial. at that period there were in residence in cambridge, and particularly at trinity, a large number of very brilliant men. airy was essentially a cambridge man. he had come up poor and friendless: he had gained friends and fame at the university, and his whole work had been done there. from the frequent references in after times both by him and his wife to their life at cambridge, it is clear that they had a very pleasant recollection of it, and that the social gatherings there were remarkably attractive. he has himself recorded that with whewell and sedgwick, and his accomplished sisters-in-law, who were frequently on long visits at the observatory, they formed pretty nearly one family. his friendship with whewell was very close. although whewell was at times hasty, and rough-mannered, and even extremely rude, yet he was generous and large-minded, and thoroughly upright. [footnote: the following passage occurs in a letter from airy to his wife, dated 1845, sept. 17th: "i am sorry that ---speaks in such terms of the 'grand master,' as she used to be so proud of him: it is only those who have _well_ gone through the ordeal of quarrels with him and almost insults from him, like sheepshanks and me, that thoroughly appreciate the good that is in him: i am sure he will never want a good word from me."] in power of mind, in pursuits, and interests, airy had more in common with whewell than with any other of his friends. it was with whewell that he undertook the experiments at dolcoath: it was to whewell that he first communicated the result of his remarkable investigation of the long inequality of venus and the earth; and some of his optical researches were conducted jointly with whewell. whewell took his degree in 1816, seven years before airy, and his reputation, both for mathematical and all-round knowledge, was extremely and deservedly great, but he was always most generous in his recognition of airy's powers. thus in a letter of mar. 16th, 1823 (life of william whewell by mrs stair douglas), he says, "airy is certainly a most extraordinary man, and deserves everything that can be said of him"; and again in the autumn of 1826 he writes to his aunt, "you mentioned a difficulty which had occurred to you in one of your late letters; how airy should be made professor while i was here, who, being your nephew, must of course, on that account, deserve it better than he could. now it is a thing which you will think odd, but it is nevertheless true, that airy is a better mathematician than your nephew, and has moreover been much more employed of late in such studies.... seriously speaking, airy is by very much the best person they could have chosen for the situation, and few things have given me so much pleasure as his election." how much whewell depended upon his friends at the observatory may be gathered from a letter which he wrote to his sister on dec. 21st, 1833. "we have lately been in alarm here on the subject of illness. two very near friends of mine, prof. and mrs airy, have had the scarlet fever at the same time; she more slightly, he very severely. they are now, i am thankful to say, doing well and recovering rapidly. you will recollect that i was staying with them at her father's in derbyshire in the summer. they are, i think, two of the most admirable and delightful persons that the world contains." and again on dec. 20th, 1835, he wrote to his sister ann, "my friends--i may almost say my dearest friends --professor airy and his family have left cambridge, he being appointed astronomer royal at greenwich--to me an irreparable loss; but i shall probably go and see how they look in their new abode." their close intercourse was naturally interrupted by airy's removal to greenwich, but their friendly feelings and mutual respect continued without material break till whewell's death. there was frequent correspondence between them, especially on matters connected with the conduct and teaching of the university, in which they both took a keen interest, and a warm welcome at trinity lodge always awaited mr and mrs airy when they visited cambridge. in a letter written to mrs stair douglas on feb. 11th, 1882, enclosing some of whewell's letters, there occurs the following passage: "after the decease of mrs whewell, whewell wrote to my wife a mournful letter, telling her of his melancholy state, and asking her to visit him at the lodge for a few days. and she did go, and did the honours of the house for several days. you will gather from this the relation in which the families stood." whewell died on mar. 6th, 1866, from the effects of a fall from his horse, and the following extract is from a letter written by airy to whewell's niece, mrs sumner gibson, on hearing of the death of his old friend: "the master was, i believe, my oldest surviving friend (beyond my own family), and, after an acquaintance of 46 years, i must have been one of his oldest friends. we have during that time been connected privately and officially: we travelled together and experimented together: and as opportunity served (but i need not say in very different degrees) we both laboured for our college and university. a terrible blank is left on my mind." sedgwick was probably 15 years older than airy: he took his degree in 1808. but the astonishing buoyancy of spirits and bonhomie of sedgwick fitted him for all ages alike. he was undoubtedly the most popular man in cambridge in modern times. his ability, his brightness and wit, his fearless honesty and uprightness, his plain-speaking and good humour, rendered him a universal favourite. his close alliance with airy was much more social than scientific. it is true that they made some geological excursions together, but, at any rate with airy, it was far more by way of recreation than of serious study, and sedgwick's science was entirely geological. their friendship continued till sedgwick's death, though it was once or twice imperilled by sedgwick's impulsive and hasty nature. peacock took his degree in 1813 (herschel's year), and was therefore probably 10 years older than airy. he was the earliest and staunchest friend of airy in his undergraduate years, encouraged him in every possible way, lent him books, assisted him in his studies, helped him with wise advice on many occasions, and took the greatest interest in his success. he was a good and advanced mathematician, and with a great deal of shrewdness and common-sense he united a singular kindness and gentleness of manner. it is therefore not to be wondered at that he was regarded by airy with the greatest esteem and affection, and though they were afterwards separated, by peacock becoming dean of ely and airy astronomer royal, yet their warm friendship was never broken. the following letter, written by airy to mrs peacock on receiving the news of the death of the dean, well expresses his feelings towards his old friend: trinity lodge, cambridge, _1858, dec. 4_. my dear madam, i have desired for some time to express to you my sympathies on occasion of the sad bereavement which has come upon me perhaps as strongly as upon any one not connected by family ties with my late friend. but i can scarcely give you an idea how every disposable moment of my time has been occupied. i am now called to cambridge on business, and i seize the first free time to write to you. my late friend was the first person whom i knew in college (i had an introduction to him when i went up as freshman). from the first, he desired me to consider the introduction not as entitling me to a mere formal recognition from him, but as authorizing me at all times to call on him for any assistance which i might require. and this was fully carried out: i referred to him in every difficulty: i had the entire command of his rooms and library (a very important aid in following the new course of mathematics which he had been so instrumental in introducing into the university) in his occasional absences: and in all respects i looked to him as to a parent. all my debts to other friends in the university added together are not comparable to what i owe to the late dean. latterly i need not say that i owed much to him and that i owe much to you for your kind notice of my two sons, even since the sad event which has put it out of his power to do more. in the past summer, looking to my custom of making a visit to cambridge in some part of the october term, i had determined that a visit to ely this year should not depend on the chance of being free to leave cambridge, but that, if it should be found convenient to yourself and the dean, the first journey should be made to ely. i wish that i had formed the same resolution one or two years ago. with many thanks for your kindness, and with deep sympathy on this occasion, i am, my dear madam, yours very faithfully, g.b. airy. sheepshanks was a fellow of trinity, in orders: he was probably seven years older than airy (he took his degree in 1816). he was not one of airy's earliest friends, but he had a great taste and liking for astronomy, and the friendship between them when once established became very close. he was a very staunch and fearless friend, an able and incisive writer, and remarkably energetic and diligent in astronomical investigations. he, or his sister, miss sheepshanks, had a house in london, and sheepshanks was very much in london, and busied himself extremely with the work of the royal observatory, that of the board of longitude, and miscellaneous astronomical matters. he was most hospitable to his friends, and while airy resided at cambridge his house was always open to receive him on his frequent visits to town. in the various polemical discussions on scientific matters in which airy was engaged, sheepshanks was an invaluable ally, and after airy's removal to greenwich had more or less separated him from his cambridge friends, sheepshanks was still associated with him and took a keen interest in his greenwich work. and this continued till sheepshanks's death. the warmest friendship always subsisted between the family at the observatory and mr and miss sheepshanks. there were many other friends, able and talented men, but these four were the chief, and it is curious to note that they were all much older than airy. it would seem as if airy's knowledge had matured in so remarkable a manner, and the original work that he produced was so brilliant and copious, that by common consent he ranked with men who were much his seniors: and the natural gravity and decorum of his manners when quite a young man well supported the idea of an age considerably greater than was actually the case. chapter v. at greenwich observatory--1836 to 1846. 1836 "through the last quarter of 1835 i had kept everything going on at the greenwich observatory in the same manner in which mr pond had carried it on. with the beginning of 1836 my new system began. i had already prepared 30 printed skeleton forms (a system totally unknown to mr pond) which were now brought into use. and, having seen the utility of the copying press in merchants' offices, i procured one. from this time my correspondence, public and private, is exceedingly perfect. "at this time the dwelling house was still unconnected with the observatory. it had no staircase to the octagon room. four new rooms had been built for me on the western side of the dwelling house, but they were not yet habitable. the north-east dome ground floor was still a passage room. the north terrace was the official passage to the north-west dome, where there was a miserable equatoreal, and to the 25-foot zenith tube (in a square tower like a steeple, which connected the n.w. dome with flamsteed's house). the southern boundary of the garden ran down a hollow which divides the peninsula from the site of the present magnetic observatory, in such a manner that the principal part of the garden was fully exposed to the public. the computing room was a most pitiful little room. there was so little room for me that i transported the principal table to a room in my house, where i conducted much of my own official business. a large useless reflecting telescope (ramage's), on the plan and nearly of the size of sir w. herschel's principal telescope, encumbered the centre of the front court. "on jan. 11th i addressed mr buck, agent of the princess sophia of gloucester, ranger of greenwich park, for leave to enclose a portion of the ground overlooking my garden. this was soon granted, and i was partially delivered from the inconvenience of the public gaze. the liberation was not complete till the magnetic ground was enclosed in 1837. "in the inferior departments of the admiralty, especially in the hydrographic office (then represented by captain beaufort) with which i was principally connected, the observatory was considered rather as a place for managing government chronometers than as a place of science. the preceding first assistant (taylor) had kept a book of letter references, and i found that out of 840 letters, 820 related to government chronometers only. on jan. 17th i mentally sketched my regulations for my own share in chronometer business. i had some correspondence with captain beaufort, but we could not agree, and the matter was referred to the admiralty. finally arrangements were made which put the chronometer business in proper subordination to the scientific charge of the observatory. "in my first negociations with the admiralty referring to acceptance of the office of astronomer royal, in 1834, lord auckland being then first lord of the admiralty, i had stipulated that, as my successor at cambridge would be unprepared to carry on my lectures, i should have permission to give a final course of lectures there. at the end of 1835 lord auckland was succeeded by lord minto: i claimed the permission from him and he refused it. when this was known in cambridge a petition was presented by many cambridge residents, and lord minto yielded. on april 18th i went to cambridge with my wife, residing at the bull inn, and began lectures on april 21st: they continued (apparently) to may 27th. my lecture-room was crowded (the number of names was 110) and the lectures gave great satisfaction. i offered to the admiralty to put all the profits in their hands, and transmitted a cheque to the accountant general of the navy: but the admiralty declined to receive them. "on june 4th the annual visitation of the observatory was held, mr f. baily in the chair. i presented a written report on the observatory (a custom which i had introduced at cambridge) in which i did not suppress the expression of my feelings about chronometer business. the hydrographer, captain beaufort, who was one of the official visitors, was irritated: and by his influence the report was not printed. i kept it and succeeding reports safe for three years, and then the board of visitors agreed to print them; and four reports were printed together, and bound with the greenwich observations of 1838. "in the course of this year i completed the volume of observations made at cambridge observatory in 1835 and on nov. 10th the printed copies were distributed. about the end of 1835 the dome for the northumberland telescope was erected: but apparently the polar frame was not erected." the following account of an accident which occurred during the construction of the dome is extracted from a letter by airy to his wife dated 1836 jan. 31st. "the workmen's account of the dome blowing off is very curious: it must have been a strange gust. it started suddenly when the men were all inside and beaumont was looking up at it: the cannon balls were thrown in with great violence (one of them going between the spokes of ransomes' large casting), and instantly after the dome had started, the boards of the outside scaffolding which had been tossed up by the same gust dropped down into the gap which the dome had left. it is a wonder that none of the men were hurt and that the iron was not broken. the dome is quite covered and i think does not look so well as when the hooping was visible." "previous to 1836 i had begun to contemplate the attachment of magnetic observations to the observatory, and had corresponded with prof. christie, prof. lloyd, prof. j. d. forbes, and mr gauss on the subject. on jan. 12th 1836 i addressed a formal letter to the admiralty, and on jan. 18th received their answer that they had referred it to the board of visitors. on march 25th i received authority for the expenditure of _â£30_, and i believe that i then ordered merz's 2-foot magnet. the visitors met on feb. 26th and after some discussion the site was chosen and the extent of ground generally defined, and on dec. 22nd mr spring rice (lord monteagle) as chancellor of the exchequer virtually effected the transfer of the ground. but no further steps were taken in 1836. a letter on a systematic course of magnetic observations in various parts of the world was addressed by baron alexander humboldt to the duke of sussex, president of the royal society; and was referred to prof. christie and me. we reported on it on june 9th 1836, strongly recommending the adoption of the scheme. "a plan had been proposed by the promoters of the london and gravesend railway (col. landman, engineer) for carrying a railway at high level across the bottom of the park. on jan. 9th i received orders from the admiralty to examine into its possible effect in producing vibrations in the observatory. after much correspondence, examination of ground, &c., i fixed upon a part of the greenwich railway (not yet opened for traffic) near the place where the croydon trunk line now joins it, as the place for trains to run upon, while i made observations with a telescope viewing a collimator by reflection in mercury at the distance of 500 feet. the experiments were made on jan. 25th, and i reported on feb. 4th. it was shewn that there would be some danger to the observatory. on nov. 2nd mr james walker, engineer, brought a model of a railway to pass by tunnel under the lower part of the park: apparently this scheme was not pressed. "in addition to the routine work of the observatory, a special set of observations were made to determine the mass of jupiter.--also the solar eclipse of may 15th was observed at greenwich in the manner which i had introduced at cambridge.--the ordnance zenith sector, and the instruments for the st helena observatory were brought for examination.--much attention was given to chronometers, and various steps were taken for their improvement.--i had some important correspondence with mr (sir john) lubbock, upon the lunar theory generally and his proposed empirical lunar tables. this was the first germ of the great reduction of lunar observations which i subsequently carried out.--in october i was nominated on the council of the royal society, having been admitted a fellow on feb. 18th 1836. i was president of the astronomical society during this and the preceding year (1836 and 1835). "my connection with groombridge's catalogue of stars began in 1832, and the examination, in concert with mr baily, of the edition printed by mr henry taylor, resulted in its condemnation. in 1834 i volunteered to the admiralty to prepare a new edition, and received their thanks and their authority for proceeding. it required a great deal of examination of details, and much time was spent on it in 1836: but it was not brought to the state of readiness for press. "my predecessor, mr pond, died on sept. 7th 1836, and was interred in halley's tomb in lee churchyard." * * * * * the following letter was written by airy in support of the application for a pension to mrs pond, who had been left in great distress: to henry warburton, esq. "the points upon which in my opinion mr pond's claims to the gratitude of astronomers are founded, are principally the following. _first_ and chief, the accuracy which he introduced into all the principal observations. this is a thing which from its nature it is extremely difficult to estimate now, so long after the change has been made, and i can only say that so far as i can ascertain from books the change is one of very great extent: for certainty and accuracy, astronomy is quite a different thing from what it was, and this is mainly due to mr pond. the most striking exemplification of this is in his laborious working out of every conceivable cause or indication of error in the circle and the two circles: but very great praise is also due for the new system which he introduced in working the transit. in comparing mr pond's systems of observation with dr maskelyne's, no one can avoid being impressed with the inferiority of dr maskelyne's. it is very important to notice that the continental observatories which have since attracted so much attention did not at that time exist or did not exist in vigour. _secondly_, the attention bestowed by mr pond on those points (chiefly of sidereal astronomy) which he regarded as fundamental: to which such masses of observations were directed as entirely to remove the doubts from probable error of individual observations or chance circumstances which have injured many other determinations. _thirdly_, the regularity of observation. the effect of all these has been that, since the commencement of mr pond's residence at greenwich, astronomy considered as an accurate representation of the state of the heavens in the most material points has acquired a certainty and an extent which it never had before. there is no period in the history of the science so clean. on some matters (in regard to the choice of observations) i might say that my own judgment would have differed in some degree from mr pond's, but one thing could have been gained only by giving up another, and upon the general accuracy no improvement could have been made. mr pond understood nothing of physical astronomy; but neither did anybody else, in england. "the supposed decrease of general efficiency in the last few years is to be ascribed to the following causes: 1. mr pond's ill health. 2. the inefficiency of his first assistant. 3. the oppression of business connected with chronometers. "the last of these, as i have reason to think, operated very far. business of this nature which (necessarily) is _daily_ and _peremptory_ will always prevail over that which is _general_ and _confidential_. i will not trouble you with an account of the various ways in which the chronometer business teazed the astronomer royal (several alterations having been made at my representation), but shall merely remark that much of the business had no connection whatever with astronomy. "i beg to submit these remarks to your perusal, requesting you to point out to me _what part_ of them should be laid before any of the king's ministers, _at what time, in what shape_, and to whom addressed. i am quite sure that mrs pond's claims require nothing to ensure favourable consideration but the impression of such a feeling of mr pond's astronomical merits as must be entertained by any reasonable astronomer; and i am most anxious to assist in conveying this impression. "of private history: i went to suffolk for a week on mar. 25th. on sept. 19th my son wilfrid (my fourth child) was born. in october i made an excursion for a week round the coast of kent. in november i went to my brother's house at keysoe in bedfordshire: i was much exposed to cold on the return-journey, which probably aggravated the illness that soon followed. from nov. 27th i was ill; made the last journal entry of the year on dec. 6th; the next was on jan. 14th, 1837. i find that in this year i had introduced arthur biddell to the tithe commutation office, where he was soon favourably received, and from which connection he obtained very profitable employment as a valuer." 1837 "my connection with cambridge observatory was not yet finished. i had determined that i would not leave a figure to be computed by my successor. in october i had (at my private expense) set mr glaisher to work on reducing the observations of sun, moon, and planets made in 1833, 1834, 1835; and subsequently had the calculations examined by mr hartnup. this employed me at times through 1837. i state here, once for all, that every calculation or other work in reference to the cambridge observatory, in this and subsequent years, was done at my private expense. the work of the northumberland telescope was going on through the year: from nov. 24th to 29th i was at cambridge on these works. "an object-glass of 6-3/4 inches aperture (a most unusual size at this time, when it was difficult to find a 4-inch or 5-inch glass) had been presented to the greenwich observatory by my friend mr sheepshanks, and on mar. 29th i received from the admiralty authority for mounting it equatoreally in the empty south dome, which had been intended for a copy of the palermo circle.--in the month of july the admiralty wished for my political assistance in a greenwich election, but i refused to give any.--on jan. 3rd i gave notice to the admiralty that i had finished the computations of groombridge's catalogue, and was ready to print. the printing was authorized and proceeded (the introduction was finished on nov. 22nd), but the book was not quite ready till the beginning of 1838.--in connection with the cavendish experiment: on june 10th i wrote to spring rice (chancellor of the exchequer) for _â£500_, which was soon granted: and from this time there is a great deal of correspondence (mainly with mr baily) upon the details of the experiment and the theory of the calculation.--on july 24th i saw the descent of the parachute by which mr cocking was killed. i attended the coroner's inquest and gave evidence a few days later. "the planetary reductions from 1750 to 1830 had been going on: the computers (glaisher, hartnup, and thomas) worked in the octagon room, and considerable advance was made.--in consequence of the agitation of the proposal by mr lubbock to form empirical tables of the moon, for which i proposed to substitute complete reduction of the observations of the moon from 1750, the british association at york (oct. 23rd, 1837) appointed a deputation (including myself) to place the matter before the government. i wrote on the matter to mr wood (lord halifax) stating that it would be proper to raise the first assistant's salary, and to give me more indefinite power about employing computers. in all these things i received cordial assistance from mr wood. the chancellor of the exchequer (mr spring rice) received us on dec. 20th: statements were furnished by me, and the business was sanctioned immediately.--during this year i was very much engaged in correspondence with lubbock and others on improvements of the lunar theory. "in the operations of 1836 and 1837 a great quantity of papers had been accumulated. i had kept them in reasonably good order, tied up in bundles: but this method began to fail in convenience, as the number increased. the great lines of classification were however now well understood. i believe it was in the latter part of the year 1837 that i finally settled on the principle of arranging papers in packets and subordinate packets, every paper being flat, by the use of four punched holes in every paper. i have never seen any principle of arrangement comparable to this. it has been adopted with the greatest ease by every assistant, and is used to the present time (1871) without alteration. "on jan. 3rd i was informed unofficially by mr wood (admiralty secretary) that the addition of the magnetic ground was sanctioned. on feb. 16th mr rhodes (an officer of the department of woods and works) came to put me formally in possession of the ground. between apr. 26th and may 13th the ground was enclosed, and my garden was completely protected from the public. the plan of the building was settled, and numerous experiments were made on various kinds of concrete: at last it was decided to build with wood. "after a dinner given by lord burlington, chancellor, the first meeting of the london university was held on mar. 4th, and others followed. on apr. 18th i handed to the chancellor a written protest against a vote of a salary of _â£1000_ to the registrar: which salary, in fact, the government refused to sanction. dissensions on the question of religious examination were already beginning, but i took little part in them. "in 1833 mr henderson had resigned the superintendance of the cape of good hope observatory, and mr maclear was appointed. i recommended the same official instructions for him (they had included an allusion to la caille's arc of meridian) with an addition on the probability of trigonometrical survey, on aug. 8th, 1837. on feb. 24th, 1837, i wrote to beaufort suggesting that bradley's sector should be used for verifying the astronomical determinations, and subsequently received the approval of the admiralty. in june sir j. herschel and i had an interview with mr wood on the cape equipment generally. the sector was erected with its new mounting, careful drawings were made of every part, instructions were prepared for its use, and on aug. 10th it was sent to woolwich dockyard and shipped for the cape. "of private history: on aug. 23rd i started with my wife for an excursion in south wales, &c. on sept. 9th i gave a lecture in the town hall of neath. while at swansea we received news of the death of my wife's father, the rev. richard smith, and returned at once.--in this year arthur biddell bought the little eye estate for me." 1838 "cambridge observatory:--on dec. 29th, 1837, i had set mr glaisher to work in collecting the annual results for star-places from the cambridge observations, to form one catalogue: i examined the calculations and the deduced catalogue, and on dec. 14, 1838, presented it to the royal astronomical society, under the title of 'the first cambridge catalogue.'--for the northumberland telescope i was engaged with simms about the clockwork from time to time up to apr. 30th, and went to cambridge about it. the instrument was brought to a useable state, but some small parts were still wanting. "at greenwich:--in april i drew up a little history of the observatory for the penny cyclopaedia.--on june 30th the lords of the admiralty paid a short visit to the observatory: on this occasion mr wood suggested a passage connecting the observatory with the dwelling-house, and i subsequently prepared sketches for it; it was made in the next year.--in the course of the year the sheepshanks equatoreal was mounted, and encke's comet was observed with it from oct. 26th to nov. 13th.--on mar. 31st, &c. i reported to the admiralty on the selection of chronometers for purchase, from a long list: this was an important beginning of a new system.--the magnetic observatory was built, in the form originally planned for it (a four-armed cross with equal arms, one axis being in the magnetic meridian) in the beginning of this year. (no alteration has since been made in form up to the present time, 1871, except that the north arm has been lengthened 8 feet a few years ago.) on may 21st a magnet was suspended for the first time, mr baily and lieut. (afterwards sir william) denison being present.--groombridge's catalogue was finished, and on mar. 3rd i arranged for sending out copies.--the planetary reductions were carried on vigorously. on may 31st, 1838, the treasury assented to the undertaking of the lunar reductions and allotted _â£2,000_ for it: preparations were made, and in the autumn 7 computers were employed upon it. it will easily be seen that this undertaking added much to my labours and cares.--the geodetic affairs of the cape of good hope began to be actively pressed, and in february beaufort wrote to me in consequence of an application from maclear, asking about a standard of length for maclear (as foundation for a geodetic survey). i made enquiries, and on mar. 13th wrote to mr wood, alluding also generally to the want of a national english standard after the destruction of the houses of parliament. on apr. 24th the admiralty sanctioned my procuring proper standard bars.--in connection with the cavendish experiment, i have an immense quantity of correspondence with mr baily, and all the mathematics were furnished by me: the experiment was not finished at the end of the year.--the perturbations of uranus were now attracting attention. i had had some correspondence on this subject with dr hussey in 1834, and in 1837 with eugã¨ne bouvard. on feb. 24th, of 1838, i wrote to schumacher regarding the error in the tabular radius-vector of uranus, which my mode of reducing the observations enabled me to see. "the national standards of length and weight had been destroyed in the fire of the houses of parliament. on may 11th i received a letter from mr spring rice, requesting me to act (as chairman) with a committee consisting of f. baily, j.e. drinkwater bethune, davies gilbert, j.g.s. lefevre, j.w. lubbock, g. peacock, and r. sheepshanks, to report on the steps now to be taken. i accepted the charge, and the first meeting was held at the observatory on may 22nd; all subsequent meetings in london, usually in the apartments of the royal astronomical society. i acted both as chairman and as working secretary. our enquiries went into a very wide field, and i had much correspondence. "on jan. 4th mr wood wrote to me, mentioning that capt. johnson had made some observations on the magnetism of iron ships, and asking whether they ought to be continued; a steamer being offered at _â£50_ per week. i applied to beaufort for a copy of johnson's observations, and on jan. 7th replied very fully, discouraging such observations; but recommending a train of observations expressly directed to theoretical points. on feb. 17th i reported that i had examined the deptford basin, and found that it would do fairly well for experiments. on july 14th, 1838, capt. beaufort wrote to me that the admiralty wished for experiments on the ship, the 'rainbow,' then in the river, and enquired whether i would undertake them and what assistance i desired, as for instance that of christie or barlow. i replied that one person should undertake it, either christie, barlow, or myself, and that a basin was desirable. on july 16th and 17th i looked at the basins of woolwich and deptford, approving the latter. on july 21st the admiralty gave me full powers. from july 23rd i was almost entirely employed on preparations. the course of operations is described in my printed paper: the original maps, curves, and graphical projections, are in the bound mss.: 'correction of compass in iron ships--"rainbow,"' at the greenwich observatory. the angular disturbances were found on july 26th and 30th, requiring some further work on a raft, so that they were finally worked out on aug. 11th. i struggled hard with the numbers, but should not have succeeded if it had not occurred to me to examine the horizontal magnetic intensities. this was done on aug. 14th, and the explanation of the whole was suggested at once: graphical projections were made on aug. 16th and 17th for comparison of my explanation with observations, and the business was complete. on aug. 17th and 18th i measured the intensity of some magnets, to be used in the ship for correction. it is to be remarked that, besides the effect of polar magnetism, there was no doubt of the existence of an effect of induced magnetism requiring correction by other induced magnetism: and experiments for this were made in the magnetic observatory. all was ready for trial: and on aug. 20th i carried my magnets and iron correctors to deptford, mounted them in the proper places, tried the ship, and the compass, which had been disturbed 50 degrees to the right and 50 degrees to the left, was now sensibly correct. on aug. 21st i reported this to the admiralty, and on aug. 24th i tried the ship to gravesend. on aug. 30th i had the loan of her for an expedition with a party of friends to sheerness, and on sept. 9th i accompanied her to gravesend, on her first voyage to antwerp.--on oct. 5th application was made to me by the owner of the 'ironsides' to correct her compasses. in consequence of this i went to liverpool on oct. 25th, and on this occasion made a very important improvement in the practical mode of performing the correction.--on nov. 16th i reported to the admiralty in considerable detail. on dec. 4th i had an interview with lord minto (first lord of the admiralty) and mr wood. they refused to sanction any reward to me.--the following is a copy of the report of the captain of the 'rainbow' after her voyage to antwerp: 'having had the command of the rainbow steamer the two voyages between london and antwerp, i have the pleasure to inform you that i am perfectly satisfied as to the correctness of the compasses, and feel quite certain they will continue so. i took particular notice from land to land from our departure and found the bearings by compass to be exact.'"--the following extracts from letters to his wife refer to the "ironsides": on oct. 28th 1838 he writes, "i worked up the observations so much as to see that the compass disturbance is not so great as in the 'rainbow' (35â° instead of 50â°), but quite enough to make the vessel worthless; and that it is quite different in direction from that in the 'rainbow'--so that if they had stolen one of the 'rainbow' correctors and put it into this ship it would have been much worse than before." and on nov. 1st he writes, "on wednesday i again went to the ship and tried small alterations in the correctors: i am confident now that the thing is very near, but we were most abominably baffled by the sluggishness of the compass." "the university of london:--on jan. 6th i attended a sub-committee meeting on the minimum of acquirements for b.a. degree, and various meetings of the senate. on july 14th i intimated to mr spring rice my wish to resign. i had various correspondence, especially with mr lubbock, and on dec. 13th i wrote to him on the necessity of stipends to members of senate. the dissensions on religious examination became very strong. i took a middle course, demanding examination in the languages and books, but absolutely refusing to claim any religious assent. i expressed this to dr jerrard, the principal representative on the religious side, by calling on him to substitute the words 'recognition of christian literature' for 'recognition of christian religion': i addressed a printed letter to lord burlington (chancellor) and the members of the senate, on this subject. "of private history: in january i made a short excursion in norfolk and suffolk, and visited prof. sedgwick at norwich. in april i paid a short visit to mr courtney at sanderstead, with my wife. on june 14th my son hubert was born. in september i went with my sister by cambridge, &c., to luddington, where i made much enquiry concerning my father and the family of airy who had long been settled there. we then visited various places in yorkshire, and arrived at brampton, near chesterfield, where mrs smith, my wife's mother, now resided. and returned by rugby. i had much correspondence with my brother and for him about private pupils and a better church living. i complained to the bishop of norwich about the mutilation of a celebrated monument in playford church by the incumbent and curate." the following extracts are from letters to his wife relating to the above-mentioned journeys: close, norwich. _1838, jan. 21_. i do not know what degree of cold you may have had last night, but here it was (i believe) colder than before--thermometer close to the house at 3â°. i have not suffered at all. however i do not intend to go to lowestoft. brampton. _1838, sept. 30th_. we began to think that we had seen enough of scarborough, so we took a chaise in the afternoon to pickering, a small agricultural town, and lodged in a comfortable inn there. on wednesday morning at 8 we started by the railroad for whitby, in a huge carriage denominated the lady hilda capable of containing 40 persons or more drawn by one horse, or in the steep parts of the railway by two horses. the road goes through a set of defiles of the eastern moorlands of yorkshire which are extremely pretty: at first woody and rich, then gradually poorer, and at last opening on a black moor with higher moors in sight: descending in one part by a long crooked inclined plane, the carriage drawing up another load by its weight: through a little tunnel: and then along a valley to whitby. the rate of travelling was about 10 miles an hour. betsy declares that it was the most agreeable travelling that she ever had. yesterday (saturday) caroline drove betsy and miss barnes drove me to clay cross to see the works at the great railroad tunnel there. coming from the north, the railroad passes up the chesterfield valley close by the town and continues up the same valley, till it is necessary for it to enter the valley which runs the opposite way towards buttersley: the tunnel passes under the high ground between these two vallies: so that it is in reality at the water-shed: it is to be i think more than a mile long, and when finished 27 feet clear in height, so it is a grand place. we saw the preparations for a blast, and heard it fired: the ladies stopping their ears in due form. 1839 "cambridge observatory:--on mar. 7th i went to cambridge on the business of the northumberland telescope: i was subsequently engaged on the accounts, and on aug. 16th i finally resigned it to prof. challis, who accepted it on aug. 19th. on sept. 11th i communicated its completion and the settlement of accounts to the duke of northumberland. the total expense was _â£1938. 9s. 2d._ + 15000 francs for the object-glass. "at greenwich observatory:--on jan. 3rd i received the last revise of the 1837 observations, and on jan. 8th the first sheet for 1838.--in july i report on selection from a long list of chronometers which had been on trial, and on sept. 2nd i pointed out to capt. beaufort that the system of offering only one price would be ruinous to the manufacture of chronometers, and to the character of those supplied to the admiralty: and that i would undertake any trouble of classifying the chronometers tried. this letter introduced the system still in use (1871), which has been most beneficial to the manufacture. on sept. 11th i proposed that all trials begin in the first week of january: this also has been in use as an established system to the present time.--it was pointed out to me that a certain chronometer was affected by external magnetic power. i remedied this by placing under it a free compass magnet: a stand was specially prepared for it. i have never found another chronometer sensibly affected by magnetism.--in november and december i tried my new double-image micrometer.--between may 16th and oct. 13th a fireproof room was constructed in the southern part of the quadrant room; and in november a small shed was erected over the entrance to the north terrace.--the position of the free meridional magnet (now mounted in the magnetic observatory) was observed at every 5 m. through 24 hours on feb. 22nd and 23rd, may 24th and 25th, aug. 30th and 31st, and nov. 29th and 30th. this was done in cooperation with the system of the magnetic union established by gauss in germany.--the reduction of the greenwich planetary and lunar observations, 1750 to 1830, went on steadily. i had six and sometimes seven computers constantly at work, in the octagon room.--as in 1838 i had a great amount of correspondence with mr baily on the cavendish experiment.--i attended as regularly as i could to the business of the university of london. the religious question did not rise very prominently. i took a very active part, and have a great deal of correspondence, on the nature of the intended examinations in hydrography and civil engineering.--on the standards commission the chief work was in external enquiries.--on june 6th i had enquiries from john quincey adams (u.s.a.) on the expense, &c., of observatories: an observatory was contemplated in america.--i had correspondence about the proposed establishment of observatories at durham, glasgow, and liverpool. "i had in this year a great deal of troublesome and on the whole unpleasant correspondence with the admiralty about the correction of the compass in iron ships. i naturally expected some acknowledgment of an important service rendered to navigation: but the admiralty peremptorily refused it. my account of the experiments &c. for the royal society is dated april 9th. the general success of the undertaking soon became notorious, and (as i understood) led immediately to extensive building of iron ships: and it led also to applications to me for correction of compasses. on jan. 9th i was addressed in reference to the royal sovereign and royal george at liverpool; july 18th the orwell; may 11th two russian ships built on the thames; sept. 4th the ships of the lancaster company. "i had much work in connection with the cape of good hope observatory, chiefly relating to the instrumental equipment and to the geodetical work. as it was considered advisable that any base measured in the cape colony should be measured with compensation bars, i applied to major jervis for the loan of those belonging to the east indian survey, but he positively refused to lend them. on jan. 20th i applied to col. colby for the compensation bars of the british survey, and he immediately assented to lending them. col. colby had suggested to the ordnance department that capt. henderson and several sappers should be sent to use the measuring bars, and it was so arranged. it still appeared desirable to have the command of some soldiers from the garrison of cape town, and this matter was soon arranged with the military authorities by the admiralty. "the following are the principal points of my private history: it was a very sad year. on jan. 24th i went with my wife to norwich, on a visit to prof. sedgwick, and in june i visited sir j. herschel at slough. on june 13th my dear boy arthur was taken ill: his malady soon proved to be scarlet fever, of which he died on june 24th at 7 in the morning. it was arranged that he should be buried in playford churchyard on the 28th, and on that day i proceeded to playford with my wife and my eldest son george richard. at chelmsford my son was attacked with slight sickness, and being a little unwell did not attend his brother's funeral. on july 1st at 4h.15m. in the morning he also died: he had some time before suffered severely from an attack of measles, and it seemed probable that his brain had suffered. on july 5th he was buried by the side of his brother arthur in playford churchyard.--on july 23rd i went to colchester on my way to walton-on-the-naze, with my wife and all my family; all my children had been touched, though very lightly, with the scarlet fever.--it was near the end of this year that my mother quitted the house (luck's) at playford, and came to live with me at greenwich observatory, where she lived till her death; having her own attendant, and living in perfect confidence with my wife and myself, and being i trust as happy as her years and widowhood permitted. my sister also lived with me at the observatory." 1840 "in the latter part of 1839, and through 1840, i had much correspondence with the admiralty, in which i obtained a complete account of the transfer of the observatory from the ordnance department to the admiralty, and the transfer of the visitation of the observatory from the royal society to the present board of visitors. in 1840 i found that the papers of the board of longitude were divided between the royal society and the admiralty: i obtained the consent of both to bring them to the observatory. "in this year i began to arrange about an annual dinner to be held at the visitation.--my double-image micrometer was much used for observations of circumpolar double stars.--in magnetism and meteorology, certain quarterly observations were kept up; but in november the system of incessant eye-observations was commenced. i refused to commence this until i had secured a 'watchman's clock' for mechanical verification of the regular attendance of the assistants.--with regard to chronometers: in this year, for the first time, i took the very important step of publishing the rates obtained by comparisons at the observatory. i confined myself on this occasion to the chronometers purchased by the admiralty. in march a pigeon-house was made for exposure of chronometers to cold.--the lunar and planetary reductions were going on steadily.--i was consulted about an observatory at oxford, where i supported the introduction of the heliometer.--the stipend of the bakerian lecture was paid to me for my explanation of brewster's new prismatic fringes.--the business of the cape observatory and survey occupied much of my time.--in 1838 the rev. h. j. rose (editor of the encyclopaedia metropolitana) had proposed my writing a paper on tides, &c.; in oct. 1840 i gave him notice that i must connect tides with waves, and in that way i will take up the subject. much correspondence on tides, &c., with whewell and others followed. "with regard to the magnetical and meteorological establishment. on june 18th mr lubbock reported from the committee of physics of the royal society to the council in favour of a magnetic and meteorological observatory near london. after correspondence with sheepshanks, lord northampton, and herschel, i wrote to the council on july 9th, pointing out what the admiralty had done at greenwich, and offering to cooperate. in a letter to lord minto i stated that my estimate was _â£550_, including _â£100_ to the first assistant: lubbock's was _â£3,000_. on aug. 11th the treasury assented, limiting it to the duration of ross's voyage. on aug. 17th wheatstone looked at our buildings and was satisfied. my estimate was sent to the admiralty, viz. _â£150_ outfit, _â£520_ annual expense; and glaisher to be superintendent. i believe this was allowed for the present; for the following year it was placed on the estimates. most of the contemplated observations were begun before the end of 1840: as much as possible in conformity with the royal society's plan. mr hind (subsequently the superintendent of the nautical almanac) and mr paul were the first extra assistants. "of private history. on feb. 29th i went to cambridge with my paper on the going fusee. on mar. 27th i went to visit mrs smith, my wife's mother, at brampton near chesterfield. i made a short visit to playford in april and a short expedition to winchester, portsmouth, &c., in june. from sept. 5th to oct. 3rd i was travelling in the north of england and south of scotland." [this was an extremely active and interesting journey, in the course of which a great number of places were visited by airy, especially places on the border mentioned in scott's poems, which always had a great attraction for him. he also attended a meeting of the british association at glasgow and made a statement regarding the planetary and lunar reductions: and looked at a site for the glasgow observatory.] "in november i went for a short time to cambridge and to keysoe (my brother's residence). on dec. 26th my daughter hilda was born (subsequently married to e.j. routh). in this year i had a loss of _â£350_ by a fire on my eye estate." * * * * * the following extracts are from letters to his wife. some of them relate to matters of general interest. they are all of them characteristic, and serve to shew the keen interest which he took in matters around him, and especially in architecture and scenery. the first letter relates to his journey from chesterfield on the previous day. flamsteed house, _1840, april 2_. i was obliged to put up with an outside place to derby yesterday, much against my will, for i was apprehensive that the cold would bring on the pain in my face. of that i had not much; but i have caught something of sore throat and catarrh. the coach came up at about 22 minutes past 8. it arrived in derby at 20 minutes or less past 11 (same guard and coachman who brought us), and drew up in the street opposite the inn at which we got no dinner, abreast of an omnibus. i had to go to a coach office opposite the inn to pay and be booked for london, and was duly set down in a way-bill with _name_; and then entered the omnibus: was transferred to the railway station, and then received the railway ticket by shouting out my name. if you should come the same way, you would find it convenient to book your place at chesterfield to london by your name (paying for the whole, namely, coach fare, omnibus fare _-/6_, and railway fare _â£1. 15s. 0d._ first class). then you will only have to step out of the coach into the omnibus, and to scream out once or twice to the guard to make sure that you are entered in the way-bill and that your luggage is put on the omnibus. * * * * * flamsteed house, greenwich, _1840, april 15_. i forgot to tell you that at lord northampton's i saw some specimens of the daguerrotype, pictures made by the camera obscura, and they surpass in beauty of execution anything that i could have imagined. baily who has two or three has promised to lend them for your inspection when you return. also i saw some post-office stamps and stamped envelopes: i do not much admire the latter. * * * * * the following relates to the fire on his eye farm, referred to above: playford, _1840, april 23_. on wednesday (yesterday) went with my uncle to the eye estate, to see the effects of the fire. the farming buildings of every kind are as completely cleared away as if they had been mown down: not a bit of anything but one or two short brick walls and the brick foundations of the barns and stacks. the aspect of the place is much changed, because in approaching the house you do not see it upon a back-ground of barns, &c., but standing alone. the house is in particularly neat and good order. i did not think it at all worth while to make troublesome enquiries of the people who reside there, but took mr case's account. there seems no doubt that the fire was caused by the maid-servant throwing cinders into a sort of muck-place into which they had been commonly thrown. i suppose there was after all this dry weather straw or muck drier than usual, and the cinders were hotter than usual. the whole was on fire in an exceedingly short time; and everything was down in less than an hour. two engines came from eye, and all the population of the town (as the fire began shortly after two o'clock in the afternoon). it is entirely owing to these that my house, and the farm (sewell's) on the opposite side of the road, were not burned down. at the beginning of the fire the wind was n.e. which blew directly towards the opposite farm (sewell's): although the nearest part of it (tiled dwelling house) was 100 yards off or near it, and the great barn (thatched roof) considerably further, yet both were set on fire several times. all this while, the tail of my house was growing very hot: and shortly after the buildings fell in burning ruins, the wind changed to n.w., blowing directly to my house. if this change had happened while the buildings were standing and burning, there would have been no possibility of saving the house. as it was, the solder is melted from the window next the farm-yard, and the roof was set on fire in three or four places. one engine was kept working on my house and one on the opposite farm. a large pond was pretty nearly emptied. mr case's horses and bullocks were got out, not without great difficulty, as the progress of the fire was fearfully rapid. a sow and nine pigs were burnt, and a large hog ran out burnt so much that the people killed it immediately. * * * * * george inn, winchester, _1840, june 21_. at winchester we established ourselves at the george and then without delay proceeded to st cross. i did not know before the nature of its hospital establishment, but i find that it is a veritable set of alms-houses. the church is a most curious specimen of the latest norman. i never saw one so well marked before--norman ornaments on pointed arches, pilasters detached with cushion capitals, and various signs: and it is clearly an instance of that state of the style when people had been forced by the difficulties and inelegancies of the round arch in groining to adopt pointed arches for groining but had not learnt to use them for windows.......this morning after breakfast went to the cathedral (looking by the way at a curious old cross in the street). i thought that its inside was wholly norman, and was most agreeably surprised by finding the whole inside groined in every part with excellent late decorated or perpendicular work. yet there are several signs about it which lead me to think that the whole inside has been norman, and even that the pilasters now worked up into the perpendicular are norman. the transepts are most massive old norman, with side-aisles running round their ends (which i never saw before). the groining of the side aisles of the nave very effective from the strength of the cross ribs. the clerestory windows of the quire very large. the organ is on one side. but the best thing about the quire is the wooden stall-work, of early decorated, very beautiful. a superb lady chapel, of early english. * * * * * portsmouth, _1840, june 23_. we left winchester by evening train to the dolphin, southampton, and slept there. at nine in the morning we went by steamboat down the river to ryde in the isle of wight: our steamer was going on to portsmouth, but we thought it better to land at ryde and take a boat for ourselves. we then sailed out (rather a blowing day) to the vessel attending col. pasley's operations, and after a good deal of going from one boat to another (the sea being so rough that our boat could not be got up to the ships) and a good deal of waiting, we got on board the barge or lump in which col. pasley was. here we had the satisfaction of seeing the barrel of gunpowder lowered (there was more than a ton of gunpowder), and seeing the divers go down to fix it, dressed in their diving helmets and supplied with air from the great air-pump above. when all was ready and the divers had ascended again, the barge in which we were was warped away, and by a galvanic battery in another barge (which we had seen carried there, and whose connection with the barrel we had seen), upon signal given by sound of trumpet, the gunpowder was fired. the effect was most wonderful. the firing followed the signal instantaneously. we were at between 100 and 200 yards from the place (as i judge), and the effects were as follows. as soon as the signal was given, there was a report, louder than a musket but not so loud as a small cannon, and a severe shock was felt at our feet, just as if our barge had struck on a rock. almost immediately, a very slight swell was perceived over the place of the explosion, and the water looked rather foamy: then in about a second it began to rise, and there was the most enormous outbreak of spray that you can conceive. it rose in one column of 60 or 70 feet high, and broad at the base, resembling a stumpy sheaf with jagged masses of spray spreading out at the sides, and seemed to grow outwards till i almost feared that it was coming to us. it sunk, i suppose, in separate parts, for it did not make any grand squash down, and then there were seen logs of wood rising, and a dense mass of black mud, which spread gradually round till it occupied a very large space. fish were stunned by it: our boatmen picked up some. it was said by all present that this was the best explosion which had been seen: it was truly wonderful. then we sailed to portsmouth.......the explosion was a thing worth going many miles to see. there were many yachts and sailing boats out to see it (i counted 26 before they were at the fullest), so that the scene was very gay. * * * * * here are some notes on york cathedral after the fire: red lion hotel, redcar, _1840, sept. 7_. my first letter was closed after service at york cathedral. as soon as i had posted it, i walked sedately twice round the cathedral, and then i found the sexton at the door, who commiserating me of my former vain applications, and having the hope of lucre before his eyes, let me in. i saw the burnt part, which looks not melancholy but unfinished. every bit of wood is carried away clean, with scarcely a smoke-daub to mark where it has been: the building looks as if the walls were just prepared for a roof, but there are some deep dints in the pavement, shewing where large masses have fallen. the lower parts of some of the columns (to the height of 8 or 10 feet) are much scaled and cracked. the windows are scarcely touched. i also refreshed my memory of the chapter-house, which is most beautiful, and which has much of its old gilding reasonably bright, and some of its old paint quite conspicuous. and i looked again at the old crypt with its late norman work, and at the still older crypt of the pre-existing church. * * * * * 1841 "the routine work of the observatory in its several departments was carried on steadily during this year.--the camera obscura was removed from the n.w. turret of the great room, to make way for the anemometer.--in magnetism and meteorology the most important thing was the great magnetic storm of sept. 29th, which revealed a new class of magnetic phenomena. it was very well observed by mr glaisher, and i immediately printed and circulated an account of it.--in april i reported that the planetary reductions were completed, and furnished estimates for the printing.--in august i applied for 18,000 copies of the great skeleton form for computing lunar tabular places, which were granted.--i reported, as usual, on various papers for the royal society, and was still engaged on the cavendish experiment.--in the university of london i attended the meeting of dec. 8th, on the reduction of examiners' salaries, which were extravagant.--i furnished col. colby with a plan of a new sector, still used in the british survey.--i appealed to colby about the injury to the cistern on the great gable in cumberland, by the pile raised for the survey signal.--on jan. 3rd occurred a most remarkable tidal disturbance: the tide in the thames was 5 feet too low. i endeavoured to trace it on the coasts, and had a vast amount of correspondence: but it elicited little. "of private history: i was a short time in suffolk in march.--on mar. 31st i started with my wife (whose health had suffered much) for a trip to bath, bristol, cardiff, swansea, &c. while at swansea we received news on apr. 24th of the deadly illness of my dear mother. we travelled by neath and cardiff to bath, where i solicited a rest for my wife from my kind friend miss sutcliffe, and returned alone to greenwich. my dear mother had died on the morning of the 24th. the funeral took place at little whelnetham (near bury) on may 1st, where my mother was buried by the side of my father. we went to cambridge, where my wife consulted dr haviland to her great advantage, and returned to greenwich on may 7th.--on may 14th to 16th i was at sanderstead (rev. j. courtney) with whewell as one sponsor, at the christening of my daughter hilda.--in september i went for a trip with my sister to yorkshire and cumberland, in the course of which we visited dent (sedgwick's birthplace), and paid visits to mr wordsworth, miss southey, and miss bristow, returning to greenwich on the 30th sept.--from june 15th to 19th i visited my brother at keysoe." the following extracts are from letters written to his wife while on the above trip in yorkshire and cumberland: red lion inn, redcar, _1841, sept. 11_. we stopped at york: went to the tavern hotel. in the morning (friday) went into the cathedral. i think that it improves on acquaintance. the nave is now almost filled with scaffolding for the repair of the roof, so that it has not the bare unfinished appearance that it had when i was there last year. the tower in which the fire began seems to be a good deal repaired: there are new mullions in its windows, &c. we stopped to hear part of the service, which was not very effective. * * * * * here are notes of his visit to dentdale in yorkshire, the birthplace of his friend sedgwick: king's head, kendal, _1841, sept. 15_. the day was quite fine, and the hills quite clear. the ascent out of hawes is dull; the little branch dale is simple and monotonous, and so are the hills about the great dale which are in sight. the only thing which interested us was the sort of bird's-eye view of hardraw dell, which appeared a most petty and insignificant opening in the great hill side. but when we got to the top of the pass there was a magnificent view of ingleborough. the dale which was most nearly in front of us is that which goes down to ingleton, past the side of ingleborough. the mountain was about nine miles distant. we turned to the right and immediately descended dent-dale. the three dales (to hawes, to ingleton, and to dent) lay their heads together in a most amicable way, so that, when at the top, it is equally easy to descend down either of them. we found very soon that dent-dale is much more beautiful than that by which we had ascended. the sides of the hills are steeper, and perhaps higher: the bottom is richer. the road is also better. the river is a continued succession of very pretty falls, almost all of which have scooped out the lower strata of the rock, so that the water shoots clear over. for several miles (perhaps 10) it runs upon bare limestone without a particle of earth. from the head of the dale to the village of dent is eight miles. at about half-way is a new chapel, very neat, with a transept at its west end. the village of dent is one of the strangest places that i ever saw. narrow street, up and down, with no possibility of two carriages bigger than children's carts passing each other. we stopped at the head inn and enquired about the geolog: but he is not in the country. we then called on his brother, who was much surprised and pleased to see us. his wife came in soon after (his daughter having gone with a party to see some waterfall) and they urged us to stop and dine with them. so we walked about and saw every place about the house, church, and school, connected with the history of the geolog: and then dined. i promised that you should call there some time when we are in the north together and spend a day or two with them. mr sedgwick says it is reported that whewell will take sedbergh living (which is now vacant: trinity college is patron). then we had our chaise and went to sedbergh. the very mouth of dent-dale is more contracted than its higher parts. sedbergh is embosomed among lumping hills. then we had another carriage to drive to kendal. * * * * * here is a recollection of wordsworth: salutation, ambleside, _1841, sept. 19_. we then got our dinner at lowwood, and walked straight to ambleside, changed our shoes, and walked on to rydal to catch wordsworth at tea. miss wordsworth was being drawn about in a chair just as she was seven years ago. i do not recollect her appearance then so as to say whether she is much altered, but i think not. mr wordsworth is as full of good talk as ever, and seems quite strong and well. mrs wordsworth looks older. their son william was at tea, but he had come over only for the day or evening. there was also a little girl, who i think is mrs wordsworth's niece. 1842 "in this year i commenced a troublesome work, the description of the northumberland telescope. on sept. 9th i wrote to the duke of northumberland suggesting this, sending him a list of plates, and submitting an estimate of expense _â£120_. on sept. 19th i received the duke's assent. i applied to prof. challis (at the cambridge observatory) requesting him to receive the draughtsman, sly, in his house, which he kindly consented to do. "with regard to estimates. i now began to point out to the admiralty the inconvenience of furnishing separate estimates, viz. to the admiralty for the astronomical establishment, and to the treasury for the magnetical and meteorological establishment.--the great work of the lunar reductions proceeded steadily: 14 computers were employed on them.--with regard to the magnetical and meteorological establishment: i suppose that james ross's expedition had returned: and with this, according to the terms of the original grant, the magnetical and meteorological establishments expired. there was much correspondence with the royal society and the treasury, and ultimately sir r. peel consented to the continuation of the establishments to the end of 1845.--in this year began my correspondence with mr mitchell about the cincinnati observatory. on aug. 25 mr mitchell settled himself at greenwich, and worked for a long time in the computing room.--and in this year mr aiken of liverpool first wrote to me about the liverpool observatory, and a great deal of correspondence followed: the plans were in fact entirely entrusted to me.--july 7th was the day of the total eclipse of the sun, which i observed with my wife at the superga, near turin. i wrote an account of my observations for the royal astronomical society.--on jan. 10th i notified to mr goulburn that our report on the restoration of the standards was ready, and on jan. 12th i presented it. after this followed a great deal of correspondence, principally concerning the collection of authenticated copies of the old standards from all sides.--in some discussions with capt. shirreff, then captain superintendent of the chatham dockyard, i suggested that machinery might be made which would saw ship-timbers to their proper form, and i sent him some plans on nov. 8th. this was the beginning of a correspondence which lasted long, but which led to nothing, as will appear hereafter.--on dec. 15th, being on a visit to dean peacock at ely, i examined the drainage scoop wheel at prickwillow, and made a report to him by letter, which obtained circulation and was well known.--on may 26th the manuscript of my article, 'tides and waves,' for the encyclopaedia metropolitana was sent to the printer. i had extensive correspondence, principally on local tides, with whewell and others. tides were observed for me by colby's officers at southampton, by myself at christchurch and poole, at ipswich by ransome's man; and a great series of observations of irish tides were made on my plan under colby's direction in june, july and august.--on sept. 15th mr goulburn, chancellor of the exchequer, asked my opinion on the utility of babbage's calculating machine, and the propriety of expending further sums of money on it. i replied, entering fully into the matter, and giving my opinion that it was worthless.--i was elected an honorary member of the institution of civil engineers, london. "the reduction and printing of the astronomical observations had been getting into arrear: the last revise of the 1840 observations went to press on may 18th, 1842. on aug. 18th came into operation a new organization of assistants' hours of attendance, &c., required for bringing up reductions. i worked hard myself and my example had good effect." his reference to this subject in his report to the visitors is as follows: "i have in one of the preceding articles alluded to the backwardness of our reductions. in those which follow it i trust that i have sufficiently explained it. to say nothing of the loss, from ill health, of the services of most efficient assistants, i am certain that the quantity of current work will amply explain any backwardness. perhaps i may particularly mention that in the observations of 1840 there was an unusual quantity of equatoreal observations, and the reductions attending these occupied a very great time. but, as regards myself, there has been another cause. the reduction of the ancient lunar and planetary observations, the attention to chronometer constructions, the proposed management of the printing of papers relating to important operations at the cape of good hope; these and similar operations have taken up much of my time. i trust that i am doing well in rendering greenwich, even more distinctly than it has been heretofore, the place of reference to all the world for the important observations, and results of observations, on which the system of the universe is founded. as regards myself, i have been accustomed, in these matters, to lay aside private considerations; to consider that i am not a mere superintendent of current observations, but a trustee for the honour of greenwich observatory generally, and for its utility generally to the world; nay, to consider myself not as mere director of greenwich observatory, but (however unworthy personally) as british astronomer, required sometimes by my office to interfere (when no personal offence is given) in the concerns of other establishments of the state. if the board supports me in this view there can be little doubt that the present delay of computations, relating to current observations, will be considered by them as a very small sacrifice to the important advantage that may be gained by proper attention to the observations of other times and other places." "of private history: in february i went for a week to playford and norwich, visiting prof. sedgwick at the latter place. on mar. 1st my third daughter christabel was born. in march i paid a short visit to sir john herschel at hawkhurst. from june 12th to aug. 11th i was travelling with my wife on the continent, being partly occupied with the observation of the total eclipse of the sun on july 7th. the journey was in switzerland and north italy. in december i went to cambridge and ely, visiting dr peacock at the latter place." from feb. 23rd to 28th airy was engaged on observations of tides at southampton, christchurch, poole, and weymouth. during this expedition he wrote frequently (as he always did) to his wife on the incidents of his journey, and the following letters appear characteristic: king's arms, christchurch, or xchurch, _1842, feb. 24_. the lower of the above descriptions of my present place of abode is the correct one, as i fearlessly assert on the authority of divers direction-posts on the roads leading to it (by the bye this supports my doctrine that x in latin was not pronounced eks but khi, because the latter is the first letter of christ, for which x is here traditionally put). finding this morning that yolland (who called on me as soon as i had closed the letter to you) was perfectly inclined to go on with the tide observations at southampton, and that his corporals of sappers were conducting them in the most exemplary manner, i determined on starting at once. however we first went to look at the new docks (mud up to the knees) and truly it is a very great work. there is to be enclosed a good number of acres of water 22 feet deep: one dock locked in, the other a tidal dock or basin with that depth at low water. they are surrounded by brick walls eight feet thick at top, 10 or more at bottom; and all the parts that ever can be exposed are faced with granite. the people reckon that this work when finished will attract a good deal of the london commerce, and i should not be surprised at it. for it is very much easier for ships to get into southampton than into london, and the railway carriage will make them almost one. a very large steamer is lying in southampton water: the oriental, which goes to alexandria. the lady mary wood, a large steamer for lisbon and gibraltar, was lying at the pier. the said pier is a very pleasant place of promenade, the water and banks are so pretty, and there is so much liveliness of ships about it. well i started in a gig, in a swashing rain, which continued off and on for a good while. of the 21 miles, i should think that 15 were across the new forest. i do not much admire it. as for norman william's destruction of houses and churches to make it hunting ground, that is utter nonsense which never could have been written by anybody that ever saw it: but as to hunting, except his horses wore something like mud-pattens or snow-shoes, it is difficult to conceive it. almost the whole forest is like a great sponge, water standing in every part. in the part nearer to xchurch forest trees, especially beeches, seem to grow well. we stopped to bait at lyndhurst, a small place high up in the forest: a good view, such as it is, from the churchyard. the hills of the isle of wight occasionally in sight. on approaching xchurch the chalk cliffs of the west end of the isle of wight (leading to the needles) were partly visible; and, as the sun was shining on them, they fairly blazed. xchurch is a small place with a magnificent-looking church (with lofty clerestory, double transept, &c., but with much irregularity) which i propose to visit to-morrow. also a ruin which looks like an abbey, but the people call it a castle. there is a good deal of low land about it, and the part between the town and the sea reminded me a good deal of the estuary above cardigan, flat ill-looking bogs (generally islands) among the water. i walked to the mouth of the river (more than two miles) passing a nice little place called sandford, with a hotel and a lot of lodgings for summer sea-people. at the entrance of the river is a coastguard station, and this i find is the place to which i must go in the morning to observe the tide. i had some talk with the coastguard people, and they assure me that the tide is really double as reported. as i came away the great full moon was rising, and i could read in her unusually broad face (indicating her nearness to the earth) that there will be a powerful tide. i came in and have had dinner and tea, and am now going to bed, endeavouring to negociate for a breakfast at six o'clock to-morrow morning. it is raining cats and dogs. * * * * * luce's hotel, weymouth, _1842, feb. 27_. this morning when i got up i found that it was blowing fresh from s.w. and the sea was bursting over the wall of the eastern extremity of the esplanade very magnanimously. so (the swell not being favourable for tide-observations) i gave them up and determined to go to see the surf on the chesil bank. i started with my great-coat on, more for defence against the wind than against rain; but in a short time it began to rain, and just when i was approaching the bridge which connects the mainland with the point where the chesil bank ends at portland (there being an arm of the sea behind the chesil bank) it rained and blew most dreadfully. however i kept on and mounted the bank and descended a little way towards the sea, and there was the surf in all its glory. i cannot give you an idea of its majestic appearance. it was evidently very high, but that was not the most striking part of it, for there was no such thing as going within a considerable distance of it (the occasional outbreaks of the water advancing so far) so that its magnitude could not be well seen. my impression is that the height of the surf was from 10 to 20 feet. but the striking part was the clouds of solid spray which formed immediately and which completely concealed all the other operations of the water. they rose a good deal higher than the top of the surf, so the state of things was this. a great swell is seen coming, growing steeper and steeper; then it all turns over and you see a face just like the pictures of falls of niagara; but in a little more than one second this is totally lost and there is nothing before you but an enormous impenetrable cloud of white spray. in about another second there comes from the bottom of this cloud the foaming current of water up the bank, and it returns grating the pebbles together till their jar penetrates the very brain. i stood in the face of the wind and rain watching this a good while, and should have stood longer but that i was so miserably wet. it appeared to me that the surf was higher farther along the bank, but the air was so thickened by the rain and the spray that i could not tell. when i returned the bad weather abated. i have now borrowed somebody else's trowsers while mine are drying (having got little wet in other parts, thanks to my great-coat, which successfully brought home a hundredweight of water), and do not intend to stir out again except perhaps to post this letter. * * * * * flamsteed house, _1842, may 15_. yesterday after posting the letter for you i went per steamboat to hungerford. i then found mr vignoles, and we trundled off together, with another engineer named smith, picking up stratford by the way, to wormwood scrubs. there was a party to see the atmospheric railway in action: including (among others) sir john burgoyne, whom i met in ireland several years ago, and mr pym, the engineer of the dublin and kingstown railway, whom i have seen several times, and who is very sanguine about this construction; and mr clegg, the proposer of the scheme (the man that invented gas in its present arrangements), and messrs samuda, two jews who are the owners of the experiment now going on; and sir james south! with the latter hero and mechanician we did not come in contact. unfortunately the stationary engine (for working the air-pump which draws the air out of the pipes and thus sucks the carriages along) broke down during the experiment, but not till we had seen the carriage have one right good run. and to be sure it is very funny to see a carriage running all alone "as if the devil drove it" without any visible cause whatever. the mechanical arrangements we were able to examine as well after the engine had broken down as at any time. and they are very simple and apparently very satisfactory, and there is no doubt of the mechanical practicability of the thing even in places where locomotives can hardly be used: whether it will pay or not is doubtful. i dare say that the commissioners' report has taken a very good line of discrimination. * * * * * 1843 "in march i wrote to dr wynter (vice-chancellor) at oxford, requesting permission to see bradley's and bliss's manuscript observations, with the view of taking a copy of them. this was granted, and the books of transits were subsequently copied under mr breen's superintendence. --the following paragraph is extracted from the report to the visitors: 'in the report of last year, i stated that our reductions had dropped considerably in arrear. i have the satisfaction now of stating that this arrear and very much more have been completely recovered, and that the reductions are now in as forward a state as at any time since my connection with the observatory.' in fact the observations of 1842 were sent to press on mar. 1st, 1843.--about this year the annual dinner at the visitation began to be more important, principally under the management of capt. w.h. smyth, r.n.--in november i was enquiring about an 8-inch object-glass. i had already in mind the furnishing of our meridional instruments with greater optical powers.--on july 14th the admiralty referred to me a memorial of mr j.g. ulrich, a chronometer maker, claiming a reward for improvements in chronometers. i took a great deal of trouble in the investigation of this matter, by books, witnesses, &c., and finally reported on nov. 4th that there was no ground for claim.--in april i received the first application of the royal exchange committee, for assistance in the construction of the clock: this led to a great deal of correspondence, especially with dent.--the lunar reductions were going on in full vigour.--i had much work in connection with the cape observatory: partly about an equatoreal required for the observatory, but chiefly in getting maclear's work through the press.--in this year i began to think seriously of determining the longitude of valencia in ireland, as a most important basis for the scale of longitude in these latitudes, by the transmission of chronometers; and in august i went to valencia and examined the localities. in september i submitted a plan to the admiralty, but it was deferred.--the new commission for restoring the standards was appointed on june 20th, i being chairman. the work of collecting standards and arranging plans was going on; mr baily attending to standards of length, and prof. w.h. miller to standards of weight. we held two meetings.--a small assistance was rendered to me by mr charles may (of the firm of ransomes and may), which has contributed much to the good order of papers in the observatory. mr robert ransome had remarked my method of punching holes in the paper by a hand-punch, the places of the holes being guided by holes in a piece of card, and said that they could furnish me with something better. accordingly, on aug. 28th mr may sent me the punching machine, the prototype of all now used in the observatory. "on sept. 25th was made my proposal for an altazimuth instrument for making observations of the moon's place more frequently and through parts of her orbit where she could never be observed with meridional instruments; the most important addition to the observatory since its foundation. the board of visitors recommended it to the admiralty, and the admiralty sanctioned the construction of the instrument and the building to contain it." the following passage is quoted from the address of the astronomer royal to the board of visitors at the special meeting of nov. 10th, 1843: "the most important object in the institution and maintenance of the royal observatory has always been the observations of the moon. in this term i include the determination of the places of fixed stars which are necessary for ascertaining the instrumental errors applicable to the instrumental observations of the moon. these, as regards the objects of the institution, were merely auxiliaries: the history of the circumstances which led the government of the day to supply the funds for the construction of the observatory shews that, but for the demands of accurate lunar determinations as aids to navigation, the erection of a national observatory would never have been thought of. and this object has been steadily kept in view when others (necessary as fundamental auxiliaries) were passed by. thus, during the latter part of bradley's time, and bliss's time (which two periods are the least efficient in the modern history of the observatory), and during the latter part of maskelyne's presidency (when, for years together, there is scarcely a single observation of the declination of a star), the observations of the moon were kept up with the utmost regularity. and the effect of this regularity, as regards its peculiar object, has been most honourable to the institution. the existing theories and tables of the moon are founded entirely upon the greenwich observations; the observatory of greenwich has been looked to as that from which alone adequate observations can be expected, and from which they will not be expected in vain: and it is not perhaps venturing too much to predict that, unless some gross dereliction of duty by the managers of the observatory should occur, the lunar tables will always be founded on greenwich observations. with this impression it has long been to me a matter of consideration whether means should not be taken for rendering the series of observations of the moon more complete than it can be made by the means at present recognized in our observatories."--in illustration of the foregoing remarks, the original inscription still remaining on the outside of the wall of the octagon room of the observatory may be quoted. it runs thus: 'carolus ii's rex optimus astronomiae et nauticae artis patronus maximus speculam hanc in utriusque commodum fecit anno d'ni mdclxxvi regni sui xxviii curante iona moore milite rtsg.' "the ashburton treaty had been settled with the united states, for the boundary between canada and the state of maine, and one of its conditions was, that a straight line about 65 miles in length should be drawn through dense woods, connecting definite points. it soon appeared that this could scarcely be done except by astronomical operations. lord canning, under secretary of the foreign office, requested me to nominate two astronomers to undertake the work. i strongly recommended that military officers should carry out the work, and capt. robinson and lieut. pipon were detached for this service. on mar. 1st they took lodgings at greenwich, and worked at the observatory every day and night through the month. my detailed astronomical instructions to them were drawn out on mar. 29th. i prepared all the necessary skeleton forms, &c., and looked to their scientific equipment in every way. the result will be given in 1844. "of private history: in january i went to dover with my wife to see the blasting of a cliff there: we also visited sir j. herschel at hawkhurst. in april i was at playford, on a visit to arthur biddell. on apr. 9th my daughter annot was born. from july 22nd to august 25th i was travelling in the south of ireland, chiefly to see valencia and consider the question of determining its longitude: during this journey i visited lord rosse at birr castle, and returned to weymouth, where my family were staying at the time. in october i visited cambridge, and in december i was again at playford." the journey to cambridge (oct. 24th to 27th) was apparently in order to be present on the occasion of the queen's visit there on the 25th: the following letter relating to it was written to his wife: sedgwick's rooms, trinity college, cambridge. _1843, oct. 26, thursday_. i have this morning received your letter: i had no time to write yesterday. there are more things to tell of than i can possibly remember. the dean of ely yesterday was in a most ludicrous state of misery because his servant had sent his portmanteau (containing his scarlet academicals as well as everything else) to london, and it went to watford before it was recovered: but he got it in time to shew himself to-day. yesterday morning i came early to breakfast with sedgwick. then i walked about the streets to look at the flags. cambridge never had such an appearance before. in looking along trinity street or trumpington street there were arches and flags as close as they could stand, and a cord stretched from king's entrance to mr deck's or the next house with flags on all its length: a flag on st mary's, and a huge royal standard ready to hoist on trinity gateway: laurels without end. i applied at the registrar's office for a ticket which was to admit me to trinity court, the senate house, &c., and received from peacock one for king's chapel. then there was an infinity of standing about, and very much i was fatigued, till i got some luncheon at blakesley's rooms at 1 o'clock. this was necessary because there was to be no dinner in hall on account of the address presentation. the queen was expected at 2, and arrived about 10 minutes after 2. when she drove up to trinity gate, the vice-chancellor, masters, and beadles went to meet her, and the beadles laid down their staves, which she desired them to take again. then she came towards the lodge as far as the sundial, where whewell as master took the college keys (a bundle of rusty keys tied together by a particularly greasy strap) from the bursar martin, and handed them to the queen, who returned them. then she drove round by the turret-corner of the court to the lodge door. almost every member of the university was in the court, and there was a great hurraing except when the ceremonies were going forward. presently the queen appeared at a window and bowed, and was loudly cheered. then notice was given that the queen and prince would receive the addresses of the university in trinity hall, and a procession was formed, in which i had a good place, as i claimed rank with the professors. a throne and canopy were erected at the top of the hall, but the queen did not sit, which was her own determination, because if she had sat it would have been proper that everybody should back out before presenting the address to the prince: which operation would have suffocated at least 100 people. the queen wore a blue gown and a brown shawl with an immense quantity of gold embroidery, and a bonnet. then it was known that the queen was going to service at king's chapel at half past three: so everybody went there. i saw the queen walk up the antechapel and she looked at nothing but the roof. i was not able to see her in chapel or to see the throne erected for her with its back to the table, which has given great offence to many people. (i should have said that before the queen came i called on dr haviland, also on scholefield, also on the master of christ's.) after this she returned to trinity, and took into her head to look at the chapel. the cloth laid on the pavement was not long enough and the undergraduates laid down their gowns. several of the undergraduate noblemen carried candles to illuminate newton's statue. after this the prince went by torchlight to the library. then i suppose came dinner, and then it was made known that at half-past nine the queen would receive some members of the university. so i rigged myself up and went to the levã©e at the lodge and was presented in my turn; by the vice-chancellor as "ex-professor airy, your majesty's astronomer royal." the queen and the prince stood together, and a bow was made to and received from each. the prince recognised me and said "i am glad to see you," or something like that. next to him stood goulburn, and next lord lyndhurst, who to my great surprise spoke very civilly to me (as i will tell you afterwards). the queen had her head bare and a sort of french white gown and looked very well. she had the ribbon of the garter on her breast; but like a ninny i forgot to look whether she had the garter upon her arm. the prince wore his garter. i went to bed dead tired and got up with a headache.--about the degree to the prince and the other movements i will write again. * * * * * here is a note from cubitt relating to the blasting of the round down cliff at dover referred to above: great george street, _jan. 20th, 1843_. my dear sir, _thursday_ next the 26th at 12 is the time fixed for the attempt to blow out the foot of the "round down" cliff near dover. the galvanic apparatus has been repeatedly tried in place--that is by exploding cartridges in the very chambers of the rock prepared for the powder--with the batteries at 1200 feet distance they are in full form and act admirably so that i see but little fear of failure on that head. they have been rehearsing the explosions on the plan i most strongly recommended, that is--to fire each chamber by an independent battery and circuit and to discharge the three batteries simultaneously by signal or word of command which answers well and "no mistake." i shall write to sir john herschel to-day, and remain my dear sir, very truly yours, w. cubitt. g.b. airy, esq. * * * * * the following extracts are from letters to his wife written in ireland when on his journey to consider the determination of the longitude of valencia. skibbereen, _1843, july 28_. by the bye, to shew the quiet of ireland now, i saw in a newspaper at cork this account. at some place through which a repeal-association was to pass (i forget its name) the repealers of the place set up a triumphal arch. the police pulled it down, and were pelted by the repealers, and one of the policemen was much bruised. o'connell has denounced this place as a disgrace to the cause of repeal, and has moved in the full meeting that the inhabitants of this place be struck off the repeal list, with no exception but that of the parish priest who was proved to be absent. and o'connell declares that he will not pass through this place. now for my journey. it is a sort of half-mountain country all the way, with some bogs to refresh my eyes. valencia hotel, _1843, august 6_. it seems that my coming here has caused infinite alarm. the common people do not know what to conjecture, but have some notion that the "sappers and miners" are to build a bridge to admit the charge of cavalry into the island. an attendant of mrs fitzgerald expressed how strange it was that a man looking so mild and gentle could meditate such things "but never fear, maam, those that look so mild are always the worst": then she narrated how that her husband was building some stables, but that she was demanding of him "pat, you broth of a boy, what is the use of your building stables when these people are coming to destroy everything." i suspect that the people who saw me walking up through the storm yesterday must have thought me the prince of the powers of the air at least. hibernian hotel, tralee, _1843, august 7_. i sailed from valencia to cahersiveen town in a sail-boat up the water (not crossing at the ferry). i had accommodated my time to the wish of the boatman, who desired to be there in time for prayers: so that i had a long waiting at cahersiveen for the mail car. in walking through the little town, i passed the chapel (a convent chapel) to which the people were going: and really the scene was very curious. the chapel appeared to be overflowing full, and the court in front of it was full of people, some sitting on the ground, some kneeling, and some prostrate. there were also people in the street, kneeling with their faces towards the gate pillars, &c. it seemed to me that the priest and the chapel were of less use here than even in the continental churches, and i do not see why both parties should not have stopped at home. when the chapel broke up, it seemed as if the streets were crammed with people. the turnout that even a small village in ireland produces is perfectly amazing. 1844 "in the course of 1843 i had put in hand the engraving of the drawings of the northumberland telescope at cambridge observatory, and wrote the description for letterpress. in the course of 1844 the work was completed, and the books were bound and distributed. "the building to receive the altazimuth instrument was erected in the course of the year; during the construction a foreman fell into the foundation pit and broke his leg, of which accident he died. this is the only accident that i have known at the observatory.--the electrometer mast and sliding frame were erected near the magnetic observatory.--the six-year catalogue of 1439 stars was finished; this work had been in progress during the last few years.--in may i went to woolwich to correct the compasses of the 'dover,' a small iron steamer carrying mails between dover and ostend: this i believe was the first iron ship possessed by the admiralty.--the lunar reductions were making good progress; 16 computers were employed upon them. i made application for printing them and the required sum (_â£1000_) was granted by the treasury.--in this year commenced that remarkable movement which led to the discovery of neptune. on feb. 13th prof. challis introduced mr adams to me by letter. on feb. 15th i sent my observed places of uranus, which were wanted. on june 19th i also sent places to mr e. bouvard.--as regards the national standards, mr baily (who undertook the comparisons relating to standards of length) died soon, and mr sheepshanks then undertook the work.--i attended the meeting of the british association held at york (principally in compliment to the president, dr peacock), and gave an oral account of my work on irish tides.--at the oxford commemoration in june, the honorary degree of d.c.l. was conferred on m. struve and on me, and then a demand was made on each of us for _â£6. 6s._ for fees. we were much disgusted and refused to pay it, and i wrote angrily to dr wynter, the vice-chancellor. the fees were ultimately paid out of the university chest. "in this year the longitude of altona was determined by m. struve for the russian government. for this purpose it was essential that facilities should be given for landing chronometers at greenwich. but the consent of the customhouse authorities had first to be obtained, and this required a good deal of negotiation. ultimately the determination was completed in the most satisfactory manner. the chronometers, forty-two in number, crossed the german sea sixteen times. the transit observers were twice interchanged, in order to eliminate not only their personal equation, but also the gradual change of personal equation. on sept. 30th otto struve formally wrote his thanks for assistance rendered. "for the determination of the longitude of valencia, which was carried out in this year, various methods were discussed, but the plan of sending chronometers by mail conveyance was finally approved. from london to liverpool the chronometers were conveyed by the railways, from liverpool to kingstown by steamer, from dublin to tralee by the mail coaches, from tralee to cahersiveen by car, from cahersiveen to knightstown by boat, and from knightstown to the station on the hill the box was carried like a sedan-chair. there were numerous other arrangements, and all succeeded perfectly without a failure of any kind. thirty pocket chronometers traversed the line between greenwich and kingstown about twenty-two times, and that between kingstown and valencia twenty times. the chronometrical longitudes of liverpool observatory, kingstown station, and valencia station are 12m 0.05s, 24m 31.17s, 41m 23.25s; the geodetic longitudes, computed from elements which i published long ago in the encyclopaedia metropolitana, are 12m 0.34s, 24m 31.47s, 41m 23.06s. it appears from this that the elements to which i have alluded represent the form of the earth here as nearly as is possible. on the whole, i think it probable that this is the best arc of parallel that has ever been measured. "with regard to the maine boundary: on may 7th col. estcourt, the british commissioner, wrote to me describing the perfect success of following out my plan: the line of 64 miles was cut by directions laid out at the two ends, and the cuttings met within 341 feet. the country through which this line was to pass is described as surpassing in its difficulties the conception of any european. it consists of impervious forests, steep ravines, and dismal swamps. a survey for the line was impossible, and a tentative process would have broken the spirit of the best men. i therefore arranged a plan of operations founded on a determination of the absolute latitudes and the difference of longitudes of the two extremities. the difference of longitudes was determined by the transfer of chronometers by the very circuitous route from one extremity to the other; and it was necessary to divide the whole arc into four parts, and to add a small part by measure and bearing. when this was finished, the azimuths of the line for the two ends were computed, and marks were laid off for starting with the line from both ends. one party, after cutting more than forty-two miles through the woods, were agreeably surprised, on the brow of a hill, at seeing directly before them a gap in the woods on the next line of hill; it opened gradually, and proved to be the line of the opposite party. on continuing the lines till they passed abreast of each other, their distance was found to be 341 feet. to form an estimate of the magnitude of this error, it is to be observed that it implies an error of only a quarter of a second of time in the difference of longitudes; and that it is only one-third (or nearly so) of the error which would have been committed if the spheroidal form of the earth had been neglected. i must point out the extraordinary merit of the officers who effected this operation. transits were observed and chronometers were interchanged when the temperature was lower than 19â° below zero: and when the native assistants, though paid highly, deserted on account of the severity of the weather, the british officers still continued the observations upon whose delicacy everything depended. "of private history: from july 3rd to aug. 13th i was in ireland with my wife. this was partly a business journey in connection with the determination of the longitude of valencia. on jan. 4th i asked lord lyndhurst (lord chancellor) to present my brother to the living of helmingham, which he declined to do: but on dec. 12th he offered binbrooke, which i accepted for my brother." 1845 "a map of the buildings and grounds of the observatory was commenced in 1844, and was still in progress.--on mar. 19th i was employed on a matter which had for some time occupied my thoughts, viz., the re-arrangement of current manuscripts. i had prepared a sloping box (still in use) to hold 24 portfolios: and at this time i arranged papers a, and went on with b, c, &c. very little change has been made in these.--in reference to the time given to the weekly report on meteorology to the registrar general, the report to the board of visitors contains the following paragraph: 'the devotion of some of my assistants' time and labour to the preparation of the meteorological report attached to the weekly report of the registrar general, is, in my opinion, justified by the bearing of the meteorological facts upon the medical facts, and by the attention which i understand that report to have excited.'--on dec. 13th the sleep of astronomy was broken by the announcement that a new planet, astraea, was discovered by mr hencke. i immediately circulated notices.--but in this year began a more remarkable planetary discussion. on sept. 22nd challis wrote to me to say that mr adams would leave with me his results on the explanation of the irregularities of uranus by the action of an exterior planet. in october adams called, in my absence. on nov. 5th i wrote to him, enquiring whether his theory explained the irregularity of radius-vector (as well as that of longitude). i waited for an answer, but received none. (see the papers printed in the royal astronomical society's memoirs and monthly notices).--in the royal society, the royal medal was awarded to me for my paper on the irish tides.--in the royal astronomical society i was president; and, with a speech, delivered the medal to capt. smyth for the bedford catalogue of double stars.--on jan. 21st i was appointed (with schumacher) one of the referees for the king of denmark's comet medal: i have the king's warrant under his sign manual.--the tidal harbour commission commenced on apr. 5th: on july 21st my report on wexford harbour (in which i think i introduced important principles) was communicated. one report was made this year to the government.--in the matter of saw mills (which had begun in 1842), i had prepared a second set of plans in 1844, and in this year mr nasmyth made a very favourable report on my plan. a machinist of the chatham dock yard, sylvester, was set to work (but not under my immediate command) to make a model: and this produced so much delay as ultimately to ruin the design.--on jan. 1st i was engaged on my paper 'on the flexure of a uniform bar, supported by equal pressures at equidistant points.'" (this was probably in connection with the support of standards of length, for the commission. ed.).--in june i attended the meeting of the british association at cambridge, and on the 20th i gave a lecture on magnetism in the senate house. the following quotation relating to this lecture is taken from a letter by whewell to his wife (see life of william whewell by mrs stair douglas): "i did not go to the senate house yesterday evening. airy was the performer, and appears to have outdone himself in his art of giving clearness and simplicity to the hardest and most complex subjects. he kept the attention of his audience quite enchained for above two hours, talking about terrestrial magnetism."--on nov. 29th i gave evidence before a committee of the house of commons on dover harbour pier. "with respect to the magnetical and meteorological establishment, the transactions in this year were most important. it had been understood that the government establishments had been sanctioned twice for three-year periods, of which the second would expire at the end of 1845: and it was a question with the scientific public whether they should be continued. my own opinion was in favour of stopping the observations and carefully discussing them. and i am convinced that this would have been best, except for the subsequent introduction of self-registering systems, in which i had so large a share. there was much discussion and correspondence, and on june 7th the board of visitors resolved that 'in the opinion of the visitors it is of the utmost importance that these observations should continue to be made on the most extensive scale which the interests of those sciences may require.' the meeting of the british association was held at cambridge in june: and one of the most important matters there was the congress of magnetic philosophers, many of them foreigners. it was resolved that the magnetic observatory at greenwich be continued permanently. at this meeting i proposed a resolution which has proved to be exceedingly important. i had remarked the distress which the continuous two-hourly observations through the night produced to my assistants, and determined if possible to remove it. i therefore proposed 'that it is highly desirable to encourage by specific pecuniary reward the improvement of self-recording magnetical and meteorological apparatus: and that the president of the british association and the president of the royal society be requested to solicit the favourable consideration of her majesty's government to this subject,' which was adopted. in october the admiralty expressed their willingness to grant a reward up to _â£500_. mr charles brooke had written to me proposing a plan on sept. 23rd, and he sent me his first register on nov. 24th. on nov. 1st the treasury informed the admiralty that the magnetic observatories will be continued for a further period. "the railway gauge commission in this year was an important employment. the railways, which had begun with the manchester and liverpool railway (followed by the london and birmingham) had advanced over the country with some variation in their breadth of gauge. the gauge of the colchester railway had been altered to suit that of the cambridge railway. and finally there remained but two gauges: the broad gauge (principally in the system allied with the great western railway); and the narrow gauge (through the rest of england). these came in contact at gloucester, and were likely to come in contact at many other points--to the enormous inconvenience of the public. the government determined to interfere, beginning with a commission. on july 3rd mr laing (then on the board of trade) rode to greenwich, bearing a letter of introduction from sir john lefevre and a request from lord dalhousie (president of the board of trade) that i would act as second of a royal commission (col. sir frederick smith, airy, prof. barlow). i assented to this: and very soon began a vigorous course of business. on july 23rd and 24th i went with prof. barlow and our secretary to bristol, gloucester, and birmingham: on dec. 17th i went on railway experiments to didcot: and on dec. 29th to jan. 2nd i went to york, with prof. barlow and george arthur biddell, for railway experiments. on nov. 21st i finished a draft report of the railway gauge commission, which served in great measure as a basis for that adopted next year. "of private history: i wrote to lord lyndhurst on feb. 20th, requesting an exchange of the living to which he had presented my brother in dec. 1844 for that of swineshead: to which he consented.--on jan. 29th i went with my wife on a visit to my uncle george biddell, at bradfield st george, near bury.--on june 9th i went into the mining district of cornwall with george arthur biddell.--from aug. 25th to sept. 26th i was travelling in france with my sister and my wife's sister, georgiana smith. i was well introduced, and the journey was interesting.--on oct. 29th my son osmund was born.--mr f. baily bequeathed to me _â£500_, which realized _â£450_." here are some extracts from letters written to his wife relating to the visit to the cornish mines, &c.- pearce's hotel, falmouth, _1845, june 12th, thursday_. then we walked to the united mines in gwennap. the day was very fine and now it was perfectly broiling: and the hills here are long and steep. at the united mines we found the captain, and he invited us to join in a rough dinner, to which he and the other captains were going to sit down. then we examined one of the great pumping engines, which is considered the best in the country: and some other engines. between 3 and 4 there was to be a setting out of some work to the men by a sort of dutch auction (the usual way of setting out the work here): some refuse ores were to be broken up and made marketable, and the subject of competition was, for how little in the pound on the gross produce the men would work them up. while we were here a man was brought up who was hurt in blasting: a piece of rock had fallen on him. at this mine besides the ladder ways, they have buckets sliding in guides by which the men are brought up: and they are just preparing for work another apparatus which they say is tried successfully at another mine (tresavean): there are two wooden rods _a_ and _b_ reaching from the top to the bottom, moved by cranks from the same wheel, so that one goes up when the other goes down, and vice versã¢: each of these rods has small stages, at such a distance that when the rod _a_ is down and the rod _b_ is up, the first stage of _a_ is level with the first stage of _b_: but when the rod _a_ is up and the rod _b_ is down, the second stage of _a_ is level with the first stage of _b_: so a man who wants to descend steps on the first stage of _a_ and waits till it goes down: then he steps sideways on the first stage of _b_ and waits till it goes down: then he steps sideways to the second stage of _a_ and waits till it goes down, and so on: or if a man is coming up he does just the same. while we were here mr r. taylor came. we walked home (a long step, perhaps seven miles) in a very hot sun. went to tea to mr alfred fox, who has a house in a beautiful position looking to the outside of falmouth harbour. * * * * * penzance, _1845, june 14, saturday_. yesterday morning we breakfasted early at falmouth, and before 9 started towards gwennap. i had ascertained on thursday that john williams (the senior of a very wealthy and influential family in this country) was probably returned from london. so we drove first to his house burntcoose or barncoose, and found him and his wife at home. (they are quakers, the rest of the family are not.) sedgwick, and whewell, and i, or some of our party including me, had slept once at their house. they received george and me most cordially, and pressed us to come and dine with them after our visit to tresavean mine, of which intention i spoke in my last letter: so i named 4 o'clock as hour for dinner. after a little stay we drove to tresavean, where i found the captain of the mine prepared to send an underground captain and a pit-man to descend with us. so we changed our clothes and descended by the ladders in the pumpshaft. pretty work to descend with the huge pump-rods (garnished with large iron bolts) working violently, making strokes of 12 feet, close to our elbows; and with a nearly bottomless pit at the foot of every ladder, where we had to turn round the foot of the ladder walking on only a narrow board. however we got down to the bottom of the mine with great safety and credit, seeing all the mighty machinery on the way, to a greater depth than i ever reached before, namely 1900 feet. from the bottom of the pump we went aside a short distance into the lowest workings where two men nearly naked were driving a level towards the lode or vein of ore. here i felt a most intolerable heat: and upon moving to get out of the place, i had a dreadful feeling of feebleness and fainting, such as i never had in my life before. the men urged me to climb the ladders to a level where the air was better, but they might as well have urged me to lift up the rock. i could do nothing but sit down and lean fainting against the rocks. this arose entirely from the badness of the air. after a time i felt a trifle better, and then i climbed one short ladder, and sat down very faint again. when i recovered, two men tied a rope round me, and went up the ladder before me, supporting a part of my weight, and in this way i ascended four or five ladders (with long rests between) till we came to a level, 260 fathoms below the adit or nearly 300 fathoms below the surface, where there was a tolerable current of pretty good air. here i speedily recovered, though i was a little weak for a short time afterwards. george also felt the bad air a good deal, but not so much as i. he descended to some workings equally low in another place (towards which the party that i spoke of were directing their works), but said that the air there was by no means so bad. we all met at the bottom of the man-engine 260 fathoms below the adit. we sat still a little while, and i acquired sufficient strength and nerve, so that i did not feel the slightest alarm in the operation of ascending by the man-engine. this is the funniest operation that i ever saw: it is the only absolute novelty that i have seen since i was in the country before: it has been introduced 2-1/2 years in tresavean, and one day in the united mines. in my last letter i described the principle. in the actual use there is no other motion to be made by the person who is ascending or descending than that of stepping sideways each time (there being proper hand-holds) with no exertion at all, except that of stepping exactly at the proper instant: and not the shadow of unpleasant feeling in the motion. any woman may go with the most perfect comfort, if she will but attend to the rules of stepping, and forget that there is an open pit down to the very bottom of the mine. in this way we were pumped up to the surface, and came up as cool as cucumbers, instead of being drenched with perspiration. in my description in last letter i forgot to mention that between the stages on the moving rods which i have there described there are intermediate stages on the moving rods (for which there is ample room, inasmuch as the interval between the stages on each rod used by one person is 24 feet), and these intermediate stages are used by persons _descending_: so that there are persons _ascending_ and persons _descending_ at the same time, who never interfere with each other and never step on the same stages, but merely see each other passing on the other rods--it is a most valuable invention. we then changed our clothes and washed, and drove to barncoose, arriving in good time for the dinner. i found myself much restored by some superb sauterne with water. when we were proposing to go on to camborne, mr and mrs williams pressed us so affectionately to stop that we at length decided on stopping for the night, only bargaining for an early breakfast this morning. this morning after breakfast, we started for redruth and camborne. the population between them has increased immensely since i was here before. &c. &c. * * * * * here is a letter written to his wife while he was engaged on the business of the railway gauge commission. it contains reminiscences of some people who made a great figure in the railway world at that time, and was preceded by a letter which was playfully addressed "from the palace of king hudson, york." george inn, york, _1845, dec. 30_. i wrote yesterday from mr hudson's in time for the late post, and hope that my letter might be posted by the servant to whom it was given. our affairs yesterday were simple: we reached euston station properly, found watson there, found a carriage reserved for us, eat pork-pie at wolverton (not so good as formerly), dined at derby, and arrived in york at 5.20. on the way watson informed me that the government have awarded us _â£500_ each. sir f. smith had talked over the matter with us, and i laid it down as a principle that we considered the business as an important one and one of very great responsibility, and that we wished either that the government should treat us handsomely or should consider us as servants of the state acting gratuitously, to which they assented. i think the government have done very well. mr hudson, as i have said, met us on the platform and pressed us to dine with him (though i had dined twice). then we found the rival parties quarrelling, and had to arrange between them. this prevented me from writing for the early post. (i forgot to mention that saunders, the great western secretary, rode with us all the way). at hudson's we had really a very pleasant dinner: i sat between vernon harcourt and mrs malcolm (his sister georgiana) and near to mr hudson. this morning we were prepared at 9 at the station for some runs. brunel and other people had arrived in the night. and we have been to darlington and back, with a large party in our experimental train. george arthur biddell rode on the engine as representing me. but the side wind was so dreadfully heavy that, as regards the wants of the case, this day is quite thrown away. we have since been to lunch with vernon harcourt (mrs harcourt not at home) and then went with him to look at the cathedral. the chapter-house, which was a little injured, has been pretty well restored: all other things in good order. the cathedral looks smaller and lower than french cathedrals. now that we have come in, the lord mayor of york has just called to invite us to dinner to-morrow.--i propose to george arthur biddell that he go to newcastle this evening, in order to see glass works and other things there to-morrow, and to return when he can. i think that i can persuade barlow to stop to see the experiments out, and if so i shall endeavour to return as soon as possible. the earliest day would be the day after to-morrow. * * * * * the following extract is from a letter written to mr murray for insertion in his handbook of france, relating to the breakwater at cherbourg, which airy had visited during his journey in france in the autumn of this year. royal observatory, greenwich, _1845, oct. 8th_. my opinion on the construction i need not say ought not to be quoted: but you are quite welcome to found any general statement on it; or perhaps it may guide you in further enquiries. to make it clear, i must speak rather generally upon the subject. there are three ways in which a breakwater may be constructed. 1. by building a strong wall with perpendicular face from the bottom of the sea. 2. by making a bank with nothing but slopes towards the sea. 3. by making a sloping bank to a certain height and then building a perpendicular wall upon it.--now if the 1st of these constructions could be arranged, i have no doubt that it would be the best of all, because a sea does not _break_ against a perpendicular face, but recoils in an unbroken swell, merely making a slow quiet push at the wall, and not making a violent impact. but practically it is nearly impossible. the 2nd construction makes the sea to break tremendously, but if the sloping surface be made of square stone put together with reasonable care there is not the smallest tendency to unseat these stones. this is the principle of construction of plymouth breakwater. in the 3rd construction, the slope makes the sea to break tremendously, and then it strikes the perpendicular face with the force of a battering ram: and therefore in my opinion this is the worst construction of all. a few face-stones may easily be dislodged, and then the sea entering with this enormous force will speedily destroy the whole. this is the form of the cherbourg digue. from this you will gather that i have a full belief that plymouth breakwater will last very long, and that the digue of cherbourg, at least its upper wall, will not last long. the great bank will last a good while, gradually suffering degradation, but still protecting the road pretty well. i was assured by the officers residing on the digue that the sea which on breaking is thrown vertically upwards and then falls down upon the pavement does sometimes push the stones about which are lying there and which weigh three or four tons. i saw some preparations for the foundations of the fort at the eastern extremity of the digue. one artificial stone of concrete measured 12'9" ã� 6'7" ã� 5'7", and was estimated to weigh 25000 kilogrammes. chapter vi. at greenwich observatory--1846 to 1856. 1846 "on nov. 7th i proposed a change in the form of estimates for the observatory. the original astronomical part was provided by the admiralty, and the new magnetical and meteorological part was provided by the treasury: and the whole estimates and accounts of the observatory never appeared in one public paper. i proposed that the whole should be placed on the navy estimates, but the admiralty refused. i repeated this in subsequent years, with no success. meantime i always sent to the admiralty a duplicate of my treasury estimate with the proper admiralty estimate.--stephenson's railway through the lower part of the park, in tunnel about 850 feet from the observatory, was again brought forward. on feb. 20th it was put before me by the government, and on march 9th i made experiments at kensal green, specially on the effect of a tunnel: which i found to be considerable in suppressing the tremors. on may 6th i made my report, generally favourable, supposing the railway to be in tunnel. on may 13th i, with mr stephenson, had an interview at the admiralty with lord ellenborough and sir george cockburn. the earl appeared willing to relax in his scruples about allowing a railway through the park, when sir george cockburn made a most solemn protest against it, on the ground of danger to an institution of such importance as the observatory. i have no doubt that this protest of sir george cockburn's really determined the government. on june 10th i was informed that the government refused their consent. after this the south eastern railway company adopted the line through tranquil vale.--in consequence of the defective state of paramatta observatory i had written to sir robert peel on april 16th raising the question of a general superintending board for colonial observatories: and on june 27th i saw mr gladstone at the colonial office to enquire about the possibility of establishing local boards. on june 29th a general plan was settled, but it never came to anything.--forty volumes of the observatory mss. were bound--an important beginning.--deep-sunk thermometers were prepared by prof. forbes.--on june 22nd sir robert inglis procured an order of the house of commons for printing a paper of sir james south's, ostensibly on the effects of a railway passing through greenwich park, but really attacking almost everything that i did in the observatory. i replied to this on july 21st by a letter in the athenaeum addressed to sir robert inglis, in terms so strong and so well supported that sir james south was effectually silenced." the following extract from a letter of airy's to the earl of rosse, dated dec. 15th 1846, will shew how pronounced the quarrel between airy and south had become in consequence of the above-mentioned attack and previous differences: "after the public exposure which his conduct in the last summer compelled me to make, i certainly cannot meet him on equal terms, and desire not to meet him at all." (ed.).--"in the mag. and met. department, i was constantly engaged with mr charles brooke in the preparation and mounting of the self-registering instruments, and the chemical arrangements for their use, to the end of the year. with mr ronalds i was similarly engaged: but i had the greatest difficulty in transacting business with him, from his unpractical habits.--the equipment of the liverpool observatory, under me, was still going on: i introduced the use of siemens's chronometric governor for giving horary motion to an equatoreal there. i have since introduced the same principle in the chronograph barrel and the great equatoreal at greenwich: i consider it important.--on feb. 13th i received the astronomical society's medal for the planetary reductions.--in the university of london: at this time seriously began the discussion whether there should be a compulsory examination in matters bearing on religious subjects. after this there was no peace.--for discovery of comets three medals were awarded by schumacher and me: one to peters, two to de vico. a comet was seen by hind, and by no other observer: after correspondence, principally in 1848, the medal was refused to him.--with respect to the railway gauge commission: on jan. 1st, in our experiments near york, the engine ran off the rails. on jan. 29th the commissioners signed the report, and the business was concluded by the end of april. our recommendation was that the narrow gauge should be carried throughout. this was opposed most violently by partisans of the broad gauge, and they had sufficient influence in parliament to prevent our recommendation from being carried into effect. but the policy, even of the great western railway (in which the broad gauge originated), has supported our views: the narrow gauge has been gradually substituted for the broad: and the broad now (1872) scarcely exists.--on june 20th lord canning enquired of me about makers for the clock in the clock tower of westminster palace. i suggested vulliamy, dent, whitehurst; and made other suggestions: i had some correspondence with e. b. denison, about clocks.--i had much correspondence with stephenson about the tubular bridge over the menai straits. stephenson afterwards spoke of my assistance as having much supported him in this anxious work: on dec. 11th i was requested to make a report, and to charge a fee as a civil engineer; but i declined to do so. in january i went, with george arthur biddell, to portsmouth, to examine lord dundonald's rotary engine as mounted in the 'janus,' and made a report on the same to the admiralty: and i made several subsequent reports on the same matter. the scheme was abandoned in the course of next year; the real cause of failure, as i believe, was in the bad mounting in the ship. "the engrossing subject of this year was the discovery of neptune. as i have said (1845) i obtained no answer from adams to a letter of enquiry. beginning with june 26th of 1846 i had correspondence of a satisfactory character with le verrier, who had taken up the subject of the disturbance of uranus, and arrived at conclusions not very different from those of adams. i wrote from ely on july 9th to challis, begging him, as in possession of the largest telescope in england, to sweep for the planet, and suggesting a plan. i received information of its recognition by galle, when i was visiting hansen at gotha. for further official history, see my communications to the royal astronomical society, and for private history see the papers in the royal observatory. i was abused most savagely both by english and french." the report to the visitors contains an interesting account of the great lunar reductions, from which the following passage is extracted: "of the third section, containing the comparison of observed places with tabular places, three sheets are printed, from 1750 to 1756. this comparison, it is to be observed, does not contain a simple comparison of places, but contains also the coefficients of the various changes in the moon's place depending on changes in the elements.... the process for the correction of the elements by means of these comparisons is now going on: and the extent of this work, even after so much has been prepared, almost exceeds belief. for the longitude, ten columns are added in groups, formed in thirteen different ways, each different way having on the average about nine hundred groups. for the ecliptic polar distance, five columns are added in groups, formed in seven different ways, each different way having on the average about nine hundred groups. thus it will appear that there are not fewer than 150,000 additions of columns of figures. this part of the work is not only completed but is verified, so that the books of comparison of observed and tabular places are, as regards this work, completely cleared out. the next step is to take the means of these groups, a process which is now in hand: it will be followed by the formation and solution of the equations on which the corrections of the elements depend." the following remarks, extracted from the report to the visitors, with respect to the instrumental equipment of the observatory, embody the views of the astronomer royal at this time: "the utmost change, which i contemplate as likely to occur in many years, in regard to our meridional instruments, is the substitution of instruments of the same class carrying telescopes of larger aperture. the only instrument which, as i think, may possibly be called for by the demands of the astronomer or the astronomical public, is a telescope of the largest size, for the observation of faint nebulae and minute double stars. whether the addition of such an instrument to our apparatus would be an advantage, is, in my opinion, not free from doubt. the line of conduct for the observatory is sufficiently well traced; there can be no doubt that our primary objects ought to be the accurate determination of places of the fundamental stars, the sun, the planets, and, above all, the moon. any addition whatever to our powers or our instrumental luxuries, which should tend to withdraw our energies from these objects, would be a misfortune to the observatory." of private history: "in march i visited prof. sedgwick at norwich.--on mar. 28th the 'sir henry pottinger' was launched from fairbairn's yard on the isle of dogs, where i was thrown down and dislocated my right thumb.--from apr. 10th to 15th i was at playford.--on june 10th prof. hansen arrived, and stayed with me to july 4th.--from july 6th to 10th i was visiting dean peacock at ely.--from july 23rd to 29th i was at playford, where for the first time i lodged in my own cottage. i had bought it some time before, and my sister had superintended alterations and the addition of a room. i was much pleased thus to be connected with the happy scenes of my youth.--from aug. 10th to oct. 11th i was with my wife and her sister elizabeth smith on the continent. we stayed for some time at wiesbaden, as my nerves were shaken by the work on the railway gauge commission, and i wanted the wiesbaden waters. we visited various places in germany, and made a 10-days' excursion among the swiss mountains. at gotha we lodged with prof. hansen for three days; and it was while staying here that i heard from prof. encke (on sept. 29th) that galle had discovered the expected planet. we visited gauss at gã¶ttingen and miss caroline herschel at hannover. we had a very bad passage from hamburgh to london, lasting five days: a crank-pin broke and had to be repaired: after four days our sea-sickness had gone off, during the gale--a valuable discovery for me, as i never afterwards feared sea-sickness.--on dec. 22nd i attended the celebration of the 300th anniversary of trinity college." * * * * * the following extracts relating to the engines of the "janus" are taken from letters to his wife dated from portsmouth, jan. 6th and 7th, 1846: as soon as possible we repaired to the dock yard and presented ourselves to the admiral superintendant--admiral hyde parker (not sir hyde parker). found that the "janus" had not arrived: the admiral superintendant (who does not spare a hard word) expressing himself curiously thereon. but he had got the proper orders from the admiralty relating to me: so he immediately sent for mr taplin, the superintendant of machinery: and we went off to see the small engine of lord d--d's construction which is working some pumps and other machinery in the yard. it was kept at work a little longer than usual for us to see it. and i have no hesitation in saying that it was working extremely well. it had not been opened in any way for half a year, and not for repair or packing for a much longer time.... this morning we went to the dock yard, and on entering the engine house there was shirreff, and lord d--d soon appeared. the "janus" had come to anchor at spithead late last night, and had entered the harbour this morning. blowing weather on saturday night. we had the engine pretty well pulled to pieces, and sat contemplating her a long time. before this denison had come to us. we then went on board the "janus" with shirreff but not with lord d--d. the engines were still hot, and so they were turned backwards a little for my edification. (this was convenient because, the vessel being moored by her head, she could thus strain backwards without doing mischief.) the vacuum not good. then, after a luncheon on board, it was agreed to run out a little way. but the engines absolutely stuck fast, and would not stir a bit. this i considered a perfect godsend. so the paddle-wheels (at my desire) were lashed fast, and we are to see her opened to-morrow morning. this morning (jan. 7th) we all went off to the "janus," where we expected to find the end of the cylinder (where we believe yesterday's block to have taken place) withdrawn. but it was not near it. after a great many bolts were drawn, it was discovered that one bolt could not be drawn, and in order to get room for working at it, it was necessary to take off the end of the other cylinder. and such a job! three pulley hooks were broken in my sight, and i believe some out of my sight. however this auxiliary end was at last got off: and the people began to act on the refractory bolt. but by this time it was getting dark and the men were leaving the dockyard, so i left, arranging that what they could do in preparation for me might be done in good time to-morrow morning. 1847 "on nov. 13th i circulated an address, proposing to discontinue the use of the zenith tube, because it had been found by a long course of comparative trials that the zenith tube was not more accurate than the mural circle. the address stated that 'this want of superior efficiency of the zenith tube (which, considered in reference to the expectations that had been formed of its accuracy, must be estimated as a positive failure) is probably due to two circumstances. one is, the use of a plumb-line; which appears to be affected with various ill-understood causes of unsteadiness. the other is, the insuperable difficulty of ventilating the room in which the instrument is mounted.'--on december 20th i circulated an address, proposing a transit circle, with telescope of 8 inches aperture. the address states as follows: 'the clear aperture of the object-glass of our transit instrument is very nearly 5 inches, that of our mural circle is very nearly 4 inches.'--i had been requested by the master-general of ordnance (i think) to examine candidates for a mastership in woolwich academy, and i was employed on it in february and march, in conjunction with prof. christie.--in january i applied to lord auckland for money-assistance to make an astronomical journey on the continent, but he refused.--on mar. 19th sir james south addressed to the admiralty a formal complaint against me for not observing with the astronomical instruments: on mar. 31st i was triumphantly acquitted by the admiralty.--in june i was requested by the commissioners of railways to act as president of a commission on iron bridges (suggested by the fall of the bridge at chester). lord auckland objected to it, and i was not sorry to be spared the trouble of it.--in december i was requested, and undertook to prepare the astronomical part of the scientific manual for naval officers.--on sept. 24th occurred a very remarkable magnetic storm, to which there had been nothing comparable before. mr glaisher had it observed by eye extremely well, and i printed and circulated a paper concerning it.--hansen, stimulated by the lunar reductions, discovered two long inequalities in the motion of the moon, produced by the action of venus. in the report to the visitors this matter is thus referred to: 'in the last summer i had the pleasure of visiting prof. hansen at gotha, and i was so fortunate as to exhibit to him the corrections of the elements from these reductions, and strongly to call his attention to their certainty, the peculiarity of their fluctuations, and the necessity of seeking for some physical explanation. i have much pleasure in indulging in the thought, that it was mainly owing to this representation that prof. hansen undertook that quest, which has terminated in the discovery of his two new lunar inequalities, the most remarkable discovery, i think, in physical astronomy.'--in discussing points relating to the discovery of neptune, i made an unfortunate blunder. in a paper hastily sent to the athenaeum (feb. 18th) i said that arago's conduct had been indelicate. i perceived instantly that i had used a wrong expression, and by the very next post i sent an altered expression. this altered expression was not received in time, and the original expression was printed, to my great sorrow. i could not then apologize. but at what appeared to be the first opportunity, in december, i did apologize; and my apology was accepted. but i think that arago was never again so cordial as before.--on july 4th hebe was discovered. after this iris and flora. now commenced that train of discoveries which has added more than 100 planets to the solar system.--on oct. 8th was an annular eclipse of the sun, of which the limit of annularity passed near to greenwich. to determine the exact place, i equipped observatories at hayes, lewisham south end, lewisham village, blackwall, stratford, walthamstow, and chingford. the weather was bad and no observation was obtained.--in the royal astronomical society: in 1846, the dispute between the partisans of adams and le verrier was so violent that no medal could be awarded to either. in 1847 i (with other fellows of the society) promoted a special meeting for considering such a modification of the bye-laws that for this occasion only it might be permissible to give two medals. after two days' stormy discussion, it was rejected.--in the university of london: at a meeting in july, where the religious question was discussed, it was proposed to receive some testimonial from affiliated bodies, or to consider that or some other plan for introducing religious literature. as the propriety of this was doubtful, there was a general feeling for taking legal advice: and it was set aside solely on purpose to raise the question about legal consultation. _that_ was negatived by vote: and i then claimed the consideration of the question which we had put aside for it. by the influence of h. warburton, m.p., this was denied. i wrote a letter to be laid before the meeting on july 28th, when i was necessarily absent, urging my claim: my letter was put aside. i determined never to sit with warburton again: on aug. 2nd i intimated to lord burlington my wish to retire, and on aug. 29th he transmitted to the home secretary my resignation. he (lord burlington) fully expressed his opinion that my claim ought to have been allowed.--on june 9th, on the occasion of prince albert's state visit to cambridge, knighthood was offered to me through his secretary, prof. sedgwick, but i declined it.--in september, the russian order of st stanislas was offered to me, mr de berg, the secretary of embassy, coming to greenwich personally to announce it: but i was compelled by our government rules to decline it.--i invited le verrier to england, and escorted him to the meeting of the british association at oxford in june.--as regards the westminster clock on the parliamentary building: in may i examined and reported on dent's and whitehurst's clock factories. vulliamy was excessively angry with me. on may 31st a great parliamentary paper was prepared in return to an order of the house of lords for correspondence relating to the clock.--with respect to the saw mills for ship timber: work was going on under the direction of sylvester to mar. 18th. it was, i believe, at that time, that the fire occurred in chatham dock yard which burnt the whole of the saw-machinery. i was tired of my machinery: and, from the extending use of iron ships, the probable value of it was much diminished; and i made no effort to restore it." of private history: "in february i went to derby to see whitehurst's clock factory; and went on with my wife to brampton near chesterfield, where her mother was living.--from apr. 1st to 5th i was at playford.--on holy thursday, i walked the parish bounds (of greenwich) with the parish officers and others. from apr. 19th to 24th i was at birmingham (on a visit to guest, my former pupil, and afterwards master of caius college) and its neighbourhood, with george arthur biddell.--from june 23rd to 28th i was at oxford and malvern: my sister was at malvern, for water-cure: the meeting of the british association was at oxford and i escorted le verrier thither.--july 28th to 30th i was at brampton.--from august 10th to september 18th i was engaged on an expedition to st petersburg, chiefly with the object of inspecting the pulkowa observatory. i went by hamburg to altona, where i met struve, and started with him in an open waggon for lã¼beck, where we arrived on aug. 14th. we proceeded by steamer to cronstadt and petersburg, and so to pulkowa, where i lodged with o. struve. i was here engaged till sept. 4th, in the observatory, in expeditions in the neighbourhood and at st petersburg, and at dinner-parties, &c. i met count colloredo, count ouvaroff, count stroganoff, lord bloomfield (british ambassador), and others. on sept. 4th i went in a small steamer to cronstadt, and then in the vladimir to swinemã¼nde: we were then towed in a passage boat to stettin, and i proceeded by railway to berlin. on sept. 9th i found galle and saw the observatory. on sept. 10th i went to potzdam and saw humboldt. on the 12th i went to hamburg and lodged with schumacher: i here visited repsold and rã¼mker. on sept. 14th i embarked in the john bull for london, and arrived there on the evening of the 18th: on the 16th it was blowing 'a whole gale,' reported to be the heaviest gale known for so many hours; 4 bullocks and 24 sheep were thrown overboard.--from dec. 3rd to 8th i was at cambridge, and from the 22nd to 31st at playford." * * * * * here is a letter to his wife written from birmingham, containing a note of the progress of the ironwork for the menai bridge: edgbaston, birmingham, _1847, apr. 22_. yesterday morning we started between 10 and 11 for stourbridge, first to see some clay which is celebrated all over the world as the only clay which is fit to make pots for melting glass, &c. you know that in all these fiery regions, fire-clay is a thing of very great importance, as no furnace will stand if made of any ordinary bricks (and even with the fire-clay, the small furnaces are examined every week), but this stourbridge clay is as superior to fire-clay as fire-clay is to common brick-earth. then we went to fosters' puddling and rolling works near stourbridge. these are on a very large scale: of course much that we saw was a repetition of what we had seen before, but there were slitting mills, machines for rolling the puddled blooms instead of hammering them, &c., and we had the satisfaction of handling the puddling irons ourselves. then we went to another work of the fosters not far from dudley, where part of the work of the tube bridge for the menai is going on. the fosters are, i believe, the largest iron masters in the country, and the two principal partners, the elder mr foster and his nephew, accompanied us in all our inspections and steppings from one set of works to another. the length of tube bridge which they have in hand here is only 120 feet, about 1/4 of the whole length: and at present they are only busy on the bottom part of it: but it is a prodigious thing. i shall be anxious about it. then we went to other works of the fosters' at king's wynford, where they have blast furnaces: and here after seeing all other usual things we saw the furnaces tapped. in this district the fosters work the 10-yard coal in a way different from any body else: they work out the upper half of its thickness and then leave the ground to fall in: after a year or two this ground becomes so hard as to make a good safe roof, and then they work away the other half: thus they avoid much of the danger and difficulty of working the thick bed all at once. the ventilation of these mines scarcely ever requires fires, and then only what they call "lamps," those little fire-places which are used for giving light at night. (in the northumberland and durham pits, they constantly have immense roaring fires to make a draught.) then we came home through dudley. * * * * * during his stay in russia, there was a great desire manifested by the astronomers and scientific men of russia that he should be presented to the emperor. this would no doubt have taken place had not the movements of the court and his own want of time prevented it. the following letter to the british ambassador, lord bloomfield, relates to this matter: pulkowa, _1847, august 25th_. _wednesday evening_. my lord, i had the honour yesterday to receive your lordship's note of sunday last, which by some irregularity in the communications with this place reached me, i believe, later than it ought. from this circumstance, and also from my being made acquainted only this afternoon with some official arrangements, i am compelled to trouble you at a time which i fear is less convenient than i could have desired. the object of my present communication is, to ask whether (if the movements of the court permit it) it would be agreeable to your lordship to present me to the emperor. in explanation of this enquiry, i beg leave to state that this is an honour to which, personally, i could not think of aspiring. my presence however at pulkowa at this time is in an official character. as astronomer royal of england, i have thought it my duty to make myself perfectly acquainted with the observatory of pulkowa, and this is the sole object of my journey to russia. it is understood that the emperor takes great interest in the reputation of the observatory, and i am confident that the remarks upon it which i am able to make would be agreeable to him. i place these reasons before you, awaiting entirely your lordship's decision on the propriety of the step to which i have alluded. i am to leave st petersburg on saturday the 4th of september. i have the honor to be my lord, your lordship's very faithful servant, g. b. airy. _lord bloomfield, &c., &c._ * * * * * it was probably in acknowledgment of this letter that in due time he received the following letter with the offer of the russian order of st stanislas: monsieur l'astronome royal, sa majestã© l'empereur en apprã©ciant les travaux assidus qui vous ont donnã© une place distinguã©e au rang des plus illustres astronomes de l'europe, et la coopã©ration bienveillante, que vous n'avez cessã© de tã©moigner aux astronomes russes dans les expã©ditions, dont ils ã©taient chargã©s, et en dernier lieu par votre visite ã  l'observatoire central de poulkova, a daignã© sur mon rapport, vous nommer chevalier de la seconde classe de l'ordre impã©rial et royal de st stanislas. je ne manquerai pas de vous faire parvenir par l'entremise de lord bloomfield les insignes et la patente de l'ordre. veuillez en attendant, monsieur, recevoir mes sincã¨res fã©licitations et l'assurance de ma parfaite considã©ration. le ministre de l'instruction publique, cte ouvaroff. st pã�tersbourg, _ce_ 24 _aoã»t_, 1847 --------- 5 _septbr._ _ã  mr g. b. airy, esq., astronome royal de s. m. britannique ã  greenwich_. * * * * * airy provisionally accepted the order, but wrote at once to lord john russell the following letter of enquiry: royal observatory, greenwich, _1847, oct. 15_. my lord, in respect of the office of astronomer royal, i refer to the first lord of the treasury as official patron. in virtue of this relation i have the honour to lay before your lordship the following statement, and to solicit your instructions thereon. for conducting with efficiency and with credit to the nation the institution which is entrusted to me, i have judged it proper to cultivate intimate relations with the principal observatories of europe, and in particular with the great observatory founded by the emperor of russia at pulkowa near st petersburg. i have several times received mr struve, the director of that observatory, at greenwich: and in the past summer i made a journey to st petersburg for the purpose of seeing the observatory of pulkowa. since my return from russia, i have received a communication from count ouvaroff, minister of public instruction in the russian empire, informing me that the emperor of russia desires to confer on me the decoration of knight commander in the second rank of the order of st stanislas. and i have the honour now to enquire of your lordship whether it is permitted to me to accept from the emperor of russia this decoration. i have the honour to be, my lord, your lordship's very obedient servant, g.b. airy. _the rt honble lord john russell, &c. &c. &c. first lord of the treasury_. * * * * * the answer was as follows: downing street, _october 19, 1847_. sir, i am desired by lord john russell to acknowledge the receipt of your letter, of the 14th inst. and to transmit to you the enclosed paper respecting foreign orders by which you will perceive that it would be contrary to the regulations to grant you the permission you desire. i am, sir, your obedient servant, c.a. grey. _g. b. airy, esq_. * * * * * the passage in the regulations referred to above is quoted in the following letter to count ouvaroff: royal observatory, greenwich, _1847, oct. 22_. sir, referring to your excellency's letter of the 24 august/5 september, and to my answer of the 25th september, in which i expressed my sense of the high honor conferred on me by his majesty the emperor of russia in offering me, through your excellency, the order of st stanislas, and my pride in accepting it:--i beg leave further to acquaint you that i have thought it necessary to make enquiry of lord john russell, first lord of her majesty's treasury, as to my competency to accept this decoration from his majesty the emperor of russia: and that his lordship in reply has referred me to the following regulation of the british court; "5th. that no subject of her majesty could be allowed to accept the insignia of a foreign order from any sovereign of a foreign state, except they shall be so conferred in consequence of active and distinguished services before the enemy, either at sea, or in the field; or unless he shall have been actually employed in the service of the foreign sovereign." in consequence of the stringency of this regulation, it is my duty now to state to your excellency that i am unable to accept the decoration which his majesty the emperor of russia was pleased, through your excellency, to offer to me. i beg leave to repeat the expression of my profound reverence to his majesty and of my deep sense of the honor which he has done me. i have the honor to be, sir, your excellency's very faithful and obedient servant, g.b. airy. _to his excellency count ouvaroff, &c. &c._ in the course of the following year a very handsome gold medal, specially struck, was transmitted by count ouvaroff on the part of the emperor of russia, to mr airy. 1848 "in april i received authority to purchase of simms an 8-inch object-glass for the new transit circle for _â£300_. the glass was tested and found satisfactory. while at playford in january i drew the first plans of the transit circle: and c. may sketched some parts. definite plans were soon sent to ransomes and may, and to simms in march. the instrument and the building were proceeded with during the year. the new transit circle was to be erected in the circle room, and considerable arrangement was necessary for continuing the circle observations with the existing instruments, whilst the new instrument was under erection. when the new transit is completely mounted, the old transit instrument may be removed, and the transit room will be free for any other purpose. i propose to take it as private room for the astronomer royal.--on may 12th i made my first proposal of the reflex zenith tube. the principle of it is as follows: let the micrometer be placed close to the object-glass, the frame of the micrometer being firmly connected with the object-glass cell, and a reflecting eye-piece being used with no material tube passing over the object-glass: and let a basin of quicksilver be placed below the object-glass, but in no mechanical connection with it, at a distance equal to half the focal length of the object-glass. such an instrument would at least be free from all uncertainties of twist of plumb-line, viscosity of water, attachment of upper plumb-line microscope, attachment of lower plumb-line microscope, and the observations connected with them: and might be expected, as a result of this extreme simplicity, to give accurate results.--a considerable error was discovered in the graduation of troughton's circle, amounting in one part to six seconds, which is referred to as follows: 'this instance has strongly confirmed me in an opinion which i have long held--that no independent division is comparable in general accuracy to engine-division,--where the fundamental divisions of the engine have been made by troughton's method, and where in any case the determination by the astronomer of errors of a few divisions will suffice, in consequence of the uniformity of law of error, to give the errors of the intermediate divisions.'--the method of observing with the altazimuth is carefully described, and the effect of it, in increasing the number of observations of the moon, is thus given for the thirteen lunations between 1847, may 15, and 1848, may 30. 'number of days of complete observations with the meridional instruments, 111; number of days of complete observations with altitude and azimuth instrument, 203. the results of the observations appear very good; perhaps a little, and but a little, inferior to those of the meridional instruments. i consider that the object for which this instrument was erected is successfully attained.'--being satisfied with the general efficiency of the system arranged by mr brooke for our photographic records (of magnetical observations) i wrote to the admiralty in his favour, and on aug. 25th the admiralty ordered the payment of _â£500_ to him. a committee of the royal society also recommended a reward of _â£250_ to mr ronalds, which i believe was paid to him.--on may 1st the last revise of the lunar reductions was passed, and on may 5th, 500 copies were sent for binding.--in this year schumacher and i refused a medal to miss mitchell for a comet discovered, because the rules of correspondence had not been strictly followed: the king of denmark gave one by special favour.--in this year occurred the discovery of saturn's 8th satellite by mr lassell: upon which i have various correspondence.--on the 18th of december the degree of ll.d. was conferred upon me by the university of edinburgh.--the ipswich lectures: a wish had been expressed that i would give a series of astronomical lectures to the people of ipswich. i therefore arranged with great care the necessary apparatus, and lectured six evenings in a room (i forget its name--it might be temperance hall--high above st matthew's street), from mar. 13th to the end of the week. a shorthand writer took them down: and these formed the 'ipswich lectures,' which were afterwards published by the ipswich museum (for whose benefit the lectures were given) and by myself, in several editions, and afterwards by messrs macmillan in repeated editions under the title of 'airy's popular astronomy.'--it had been found necessary to include under one body all the unconnected commissions of sewers for the metropolis, and lord morpeth requested me to be a member. its operations began on oct. 28th. in constitution it was the most foolish that i ever knew: consisting of, i think, some 200 persons, who could not possibly attend to it. it came to an end in the next year." of private history: "i was at playford from jan. 1st to 11th, and again from jan. 17th to 25th: also at playford from june 21st to july 12th.--from aug. 23rd to sept. 12th i was in ireland on a visit to lord rosse at parsonstown, chiefly engaged on trials of his large telescope. i returned by liverpool, where i inspected the liverpool equatoreal and clockwork, and examined mr lassell's telescopes and grinding apparatus.--from dec. 6th to 20th i was at edinburgh with my wife, on a visit to prof. j. d. forbes. we made various excursions, and i attended lectures by prof. wilson and sir w. hamilton: on the 18th i gave a lecture in prof. forbes's room. i received the honorary degree of ll.d., and made a statement on the telescopes of lord rosse and mr lassell to the royal society of edinburgh. returned to greenwich by brampton." * * * * * here is a reminiscence of the "ipswich lectures," in a letter to his wife, dated playford, 1848 mar. 14, "at the proper time i went to the hall: found a chairman installed (mr western): was presented to him, and by him presented to the audience: made my bow and commenced. the room was quite full: i have rarely seen such a sea of faces; about 700 i believe. everything went off extremely well, except that the rollers of the moving piece of sky would squeak: but people did not mind it: and when first a star passed the meridian, then jupiter, then some stars, and then saturn, he was much applauded. before beginning i gave notice that i should wait to answer questions: and as soon as the lecture was finished the chairman repeated this and begged people to ask. so several people did ask very pertinent questions (from the benches) shewing that they had attended well. others came up and asked questions." * * * * * the following extracts are from letters written to his wife while on his visit to lord rosse at parsonstown in ireland. on the way he stopped at bangor and looked at the tubular bridge works, which are thus referred to: "stopped at bangor, settled _pro tem_. at the castle, and then walked past the suspension bridge towards the tube works, which are about 1-1/2 mile south-west of the suspension bridge. the way was by a path through fields near the water side: and from one or two points in this, the appearance of the suspension bridge was most majestic. the tube bridge consists of four spans, two over water and two over sloping land. the parts for the double tube over the water spans (four lengths of tube) are building on a platform as at conway, to be floated by barges as there: the parts over the sloping banks are to be built in their place, on an immense scaffolding. i suspect that, in regard to these parts, stephenson is sacrificing a great deal of money to uniformity of plan: and that it would have been much cheaper to build out stone arches to the piers touching the water.... the tube works are evidently the grand promenade of the idlers about bangor: i saw many scores of ladies and gentlemen walking that way with their baskets of provision, evidently going to gipsy in the fields close by." the castle, parsonstown, _1848, aug. 29_. after tea it was voted that the night was likely to be fine, so we all turned out. the night was uncertain: sometimes entirely clouded, sometimes partially, but objects were pretty well seen when the sky was clear: the latter part was much steadier. from the interruption by clouds, the slowness of finding with and managing a large instrument (especially as their finding apparatus is not perfectly arranged) and the desire of looking well at an object when we had got it, we did not look at many objects. the principal were, saturn and the annular nebula of lyra with the 3-feet; saturn, a remarkable cluster of stars, and a remarkable planetary nebula, with the 6-feet. with the large telescope, the evidence of the quantity of light is prodigious. and the light of an object is seen in the field without any colour or any spreading of stray light: and it is easy to see that the vision with a reflecting telescope may be much more perfect than with a refractor. with these large apertures, the rings round the stars are insensible. the planetary nebula looked a mass of living and intensely brilliant light: this is an object which i do not suppose can be seen at all in our ordinary telescopes. the definition of the stars near the zenith is extremely good: with a high power (as 800) they are points or very nearly so--indeed i believe quite so--so that it is clear that the whole light from the great 6-feet mirror is collected into a space not bigger than the point of a needle. but in other positions of the telescope the definition is not good: and we must look to-day to see what is the cause of this fault. it is not a fault in the telescope, properly so-called, but it is either a tilt of the mirror, or an edge-pressure upon the mirror when the telescope points lower down which distorts its figure, or something of that kind. so i could not see saturn at all well, for which i was sorry, as i could so well have compared his appearance with what i have seen before. i shall be very much pleased if we can make out what is the fault of adjustment, and so correct it as to get good images everywhere. it is evident that the figuring of the mirror, the polishing, and the general arrangement, are perfectly managed. the castle, parsonstown, _1848, aug. 30_. yesterday we were employed entirely about the great telescope, beginning rather late. the principal objects had relation to the fault of definition when the telescope is pointed low (which i had remarked on the preceding night), and were, to make ourselves acquainted with the mechanism of the mirror's mounting generally, and to measure in various ways whether the mirror actually does shift its place when the telescope is set to different angles of elevation. for the latter we found that the mirror actually does tilt 1/4 of an inch when the tube points low. this of itself will not account for the fault but it indicates that the lower part is held fast in a way that may cause a strain which would produce the fault. these operations and reasonings took a good deal of time. lord rosse is disposed to make an alteration in the mounting for the purpose of correcting this possible strain. the castle, parsonstown, _1848, aug. 31_. the weather here is still vexatious: but not absolutely repulsive. yesterday morning lord rosse arranged a new method of suspending the great mirror, so as to take its edgewise pressure in a manner that allowed the springy supports of its flat back to act. this employed his workmen all day, so that the proposed finish of polishing the new mirror could not go on. i took one camera lucida sketch of the instrument in the morning, dodging the heavy showers as well as i could; then, as the afternoon was extremely fine, i took another, with my head almost roasted by the sun. this last view is extremely pretty and characteristic, embracing parts of the mounting not shewn well in the others, and also shewing the castle, the observatory, and the 3-feet telescope. the night promised exceedingly well: but when we got actually to the telescope it began to cloud and at length became hopeless. however i saw that the fault which i had remarked on the two preceding nights was gone. there is now a slight exhibition of another fault to a much smaller extent. we shall probably be looking at the telescope to-day in reference to it. the castle, parsonstown, _1848, sept. 1_. yesterday we made some alterations in the mounting of the great mirror. we found that sundry levers were loose which ought to be firm, and we conjectured with great probability the cause of this, for correction of which a change in other parts was necessary. the mirror was then found to preserve its position much more fixedly than before.... at night, upon trying the telescope, we found it very faulty for stars near the zenith, where it had been free from fault before. the screws which we had driven hard were then loosened, and immediately it was made very good. then we tried with some lower objects, and it was good, almost equally good, there. for saturn it was very greatly superior to what it had been before. still it is not satisfactory to us, and at this time a strong chain is in preparation, to support the mirror edgeways instead of the posts that there were at first or the iron hoop which we had on it yesterday. nobody would have conceived that an edgewise gripe of such a mass of metal could derange its form in this way. last night was the finest night we have had as regards clouds, though perhaps not the best for definition of objects. the castle, parsonstown, _1848, sept. 2_. i cannot learn that the fault in the mirror had been noticed before, but i fancy that the observations had been very much confined to the zenith and its neighbourhood. 1849 "in july the new constant-service water-pipes to the observatory were laid from blackheath. before this time the supply of water to the observatory had been made by a pipe leading up from the lower part of the park, and was not constant.--in may the new staircase from my dwelling-house to the octagon room was commenced.--in the report to the visitors there is a curious account of mr breen's (one of the assistants) personal equation, which was found to be different in quantity for observations of the moon and observations of the stars.--the most important set of observations (of planets) was a series of measures of saturn in four directions, at the time when his ring had disappeared. they appear completely to negative the idea that saturn's form differs sensibly from an ellipsoid.--among the general remarks of the report the following appears: 'another change (in prospect) will depend on the use of galvanism; and as a probable instance of the application of this agent, i may mention that, although no positive step has hitherto been taken, i fully expect in no long time to make the going of all the clocks in the observatory depend on one original regulator. the same means will probably be employed to increase the general utility of the observatory, by the extensive dissemination throughout the kingdom of accurate time-signals, moved by an original clock at the royal observatory; and i have already entered into correspondence with the authorities of the south eastern railway (whose line of galvanic communication will shortly pass within nine furlongs of the observatory) in reference to this subject.'--i agreed with schumacher in giving no medal to mr g. p. bond; his comet was found to be petersen's. five medals were awarded for comets in 1847 (hind, colla, mauvais, brorsen, schweizer).--the liverpool observatory was finished this year: and the thanks of the town council were presented to me.--respecting fallows's observations at the cape of good hope: i had received the admiralty sanction for proceeding with calculations in 1846, and i employed computers as was convenient. on july 20th of this year i was ready with final results, and began to make enquiries about fallows's personal history, and the early history of the cape observatory. on oct. 23rd i applied for sanction for printing, which was given, and the work was soon finished off, in the astronomical society's memoirs.--in the month of march i had commenced correspondence with various persons on the imperfect state of publication of the british survey. sheets of the map were issued by scores, but not one of them had an indication of latitude or longitude engraved. i knew that great pains had been taken in giving to the principal triangulation a degree of accuracy never before reached, and in fixing the astronomical latitudes of many stations with unequalled precision. finally i prepared for the council of the royal society a very strong representation on these subjects, which was adopted and presented to the government. it was entirely successful, and the maps were in future furnished with latitude and longitude lines.--i was elected president of the royal astronomical society on feb. 9th.--in june i went with sheepshanks to see some of the operation of measuring a base on salisbury plain. the following extract from a letter to his wife dated 1849, june 27th, relates to this expedition: 'in the morning we started before eight in an open carriage to the plain: looking into old sarum on our way. the base is measured on what i should think a most unfavourable line, its north end (from which they have begun now, in verification of the old measure) being the very highest point in the whole plain, called beacon hill. the soldiers measure only 252 feet in a day, so it will take them a good while to measure the whole seven miles. while we were there col. hall (colby's successor) and yolland and cosset came.'" of private history: "i made short visits to playford in january, april and july. from july 28th to sept. 12th i made an expedition with my wife to orkney and shetland.--from dec. 24th to 26th i was at hawkhurst, on a visit to sir john herschel." 1850 "the report to the board of visitors opens with the following paragraph: 'in recording the proceedings at the royal observatory during the last year, i have less of novelty to communicate to the visitors than in the reports of several years past. still i trust that the present report will not be uninteresting; as exhibiting, i hope, a steady and vigorous adherence to a general plan long since matured, accompanied with a reasonable watchfulness for the introduction of new instruments and new methods when they may seem desirable.'--since the introduction of the self-registering instruments a good many experiments had been made to obtain the most suitable light, and the report states that 'no change whatever has been made in these instruments, except by the introduction of the light of coal-gas charged with the vapour of coal-naptha, for photographic self-registration both of the magnetic and of the meteorological instruments.... the chemical treatment of the paper is now so well understood by the assistants that a failure is almost unknown. and, generally speaking, the photographs are most beautiful, and give conceptions of the continual disturbances in terrestrial magnetism which it would be impossible to acquire from eye-observation.' --amongst the general remarks of the report it is stated that 'there are two points which have distinctly engaged my attention. the first of these is, the introduction of the american method of observing transits, by completing a galvanic circuit by means of a touch of the finger at the instant of appulse of the transiting body to the wire of the instrument, which circuit will then animate a magnet that will make an impression upon a moving paper. after careful consideration of this method, i am inclined to believe that, in prof. mitchell's form, it does possess the advantages which have been ascribed to it, and that it may possess peculiar advantages in this observatory, where the time-connection of transits made with two different instruments (the transit and the altazimuth) is of the highest importance.... the second point is, the connection of the observatory with the galvanic telegraph of the south eastern railway, and with other lines of galvanic wire with which that telegraph communicates. i had formerly in mind only the connection of this observatory with different parts of the great british island: but i now think it possible that our communications may be extended far beyond its shores. the promoters of the submarine telegraph are very confident of the practicability of completing a galvanic connection between england and france: and i now begin to think it more than possible that, within a few years, observations at paris and brussels may be registered on the recording surfaces at greenwich, and vice versa.'--prof. hansen was engaged in forming lunar tables from his lunar theory, but was stopped for want of money. on mar. 7th i represented this privately to mr baring, first lord of the admiralty; and on mar. 30th i wrote officially to the admiralty, soliciting _â£150_ with the prospect, if necessary, of making it _â£200_. on apr. 10th the admiralty gave their assent. the existence of hansen's lunar tables is due to this grant.--the king of denmark's medal for comets was discontinued, owing to the difficulties produced by the hostility of prussia.--on aug. 1st i gave to the treasury my opinion on the first proposal for a large reflector in australia: it was not strongly favourable.--in august, being (with my wife and otto struve) on a visit to lady breadalbane at taymouth castle, i examined the mountain schehallien.--as in other years, i reported on several papers for the royal society, and took part in various business for them.--in the royal astronomical society i had much official business, as president.--in march i communicated to the athenaeum my views on the exodus of the israelites: this brought me into correspondence with miss corbaux, robert stephenson, capt. vetch, and prof. j.d. forbes.--in december i went to the london custom house, to see sir t. freemantle (chairman of customs), and to see how far decimal subdivisions were used in the custom house." of private history: "from mar. 19th to 22nd i was on an expedition to folkestone, dover, dungeness, &c.--from apr. 3rd to 8th at playford, and again for short periods in june and july.--from aug. 1st to sept. 5th i was travelling in scotland with my wife and otto struve (for part of the time). at edinburgh i attended the meeting of the british association, and spoke a little in section a. i was nominated president for 1851 at ipswich. we travelled to cape wrath and returned by inverness and the caledonian canal.--i was at playford for a short time in october and december." 1851 "in this year the great shed was built (first erected on the magnetic ground, and about the year 1868 transferred to the south ground).--the chronometers were taken from the old chronometer room (a room on the upper story fronting the south, now, 1872, called library 2) and were put in the room above the computing room (where they remained for 10 or 12 years, i think): it had a chronometer-oven with gas-heat, erected in 1850.--the following passage is quoted from the report to the visitors:--'as regards meridional astronomy our equipment may now be considered complete. as i have stated above, an improvement might yet be made in our transit circle; nevertheless i do not hesitate to express my belief that no other existing meridional instrument can be compared with it. this presumed excellence has not been obtained without much thought on my part and much anxiety on the part of the constructors of the instrument (messrs ransomes and may, and mr simms). but it would be very unjust to omit the further statement that the expense of the construction has considerably exceeded the original estimate, and that this excess has been most liberally defrayed by the government.'--in december sir john herschel gave his opinion (to the admiralty, i believe) in favour of procuring for the cape observatory a transit circle similar to that at greenwich.--i had much correspondence about sending pierce morton (formerly a pupil of mine at cambridge, a clever gentlemanly man, and a high wrangler, but somewhat flighty) as magnetic assistant to the cape observatory: he was with me from may to october, and arrived at the cape on nov. 27th.--i was much engaged with the clock with conical motion of pendulum, for uniform movement of the chronographic barrel.--regarding galvanic communications: on sept. 19th i had prepared a draft of agreement with the south eastern railway company, to which they agreed. in november i wrote to sir t. baring (first lord of the admiralty) and to the admiralty for sanction, which was given on dec. 18th. in december i had various communications about laying wires through the park, &c., &c., and correspondence about the possibility of using sympathetic clocks: in june, apparently, i had seen shepherd's sympathetic clock at the great exhibition, and had seen the system of sympathetic clocks at pawson's, st paul's churchyard.--in the last quarter of this year i was engaged in a series of calculations of chronological eclipses. on sept. 30th mr bosanquet wrote to me about the eclipse of thales, and i urged on the computations related to it, through mr breen. in october the eclipse of agathocles (the critical eclipse for the motion of the moon's node) was going on. in october hansteen referred me to the darkness at stiklastad.--i went to sweden to observe the total eclipse of july 28th, having received assistance from the admiralty for the journeys of myself, mr dunkin, mr humphreys and his friend, and capt. blackwood. i had prepared a map of its track, in which an important error of the _berliner jahrbuch_ (arising from neglect of the earth's oblateness) was corrected. i gave a lecture at the royal institution, in preparation for the eclipse, and drew up suggestions for observations, and i prepared a scheme of observations for greenwich, but the weather was bad. the official account of the observations of the eclipse, with diagrams and conclusions, is given in full in a paper published in the royal astr. society's memoirs.--this year i was president of the british association, at the ipswich meeting: it necessarily produced a great deal of business. i lectured one evening on the coming eclipse. prince albert was present, as guest of sir william middleton: i was engaged to meet him at dinner, but when i found that the dinner day was one of the principal soirã©e days, i broke off the engagement.--on may 26th i had the first letter from e. hamilton (whom i had known at cambridge) regarding the selection of professors for the university of sydney. herschel, maldon, and h. denison were named as my coadjutors. plenty of work was done, but it was not finished till 1852.--in connection with the clock for westminster palace, in february there were considerations about providing other clocks for the various buildings; and this probably was one reason for my examining shepherd's clocks at the great exhibition and at pawson's. in november i first proposed that mr e.b. denison should be associated with me. about the end of the year, the plan of the tower was supplied to me, with reference to the suspension of the weights and other particulars.--in 1850 admiral dundas (m.p. for greenwich and one of the board of admiralty) had requested me to aid the trustees of the dee navigation against an attack; and on mar. 19th 1851 i went to chester to see the state of the river. on jan. 1st 1852 i went to give evidence at the official enquiry.--at a discussion on the construction of the great exhibition building in the institution of civil engineers, i expressed myself strongly on the faulty principles of its construction.--in this year i wrote my first paper on the landing of julius caesar in britain, and was engaged in investigations of the geography, tides, sands, &c., relating to the subject." of private history: "i was several times at playford during january, and went there again on dec. 23rd.--in this year a very heavy misfortune fell on us. my daughter, elizabeth, had been on a visit to lady herschel at hawkhurst, and on apr. 2nd sir j. herschel wrote to me, saying that she was so well in health. she returned a few days later, and from her appearance i was sure that she was suffering under deadly disease. after some time, an able physician was consulted, who at once pronounced it to be pulmonary. a sea voyage was thought desirable, and my wife took her to shetland, where there was again a kind welcome from mr edmonston. but this, and the care taken on her return, availed nothing: and it was determined to take her to madeira. my wife and daughter sailed in the brig 'eclipse' from southampton on dec. 11th. the termination came in 1852.--on nov. 23rd i went to bradfield, near bury: my uncle, george biddell, died, and i attended the funeral on nov. 29th.--from july 18th to aug. 24th i was in sweden for the observation of the eclipse, and returned through holland.--in october i was about a week at ventnor and torquay, and from dec. 7th to 11th at southampton, on matters connected with my daughter's illness." the following extracts are from letters to his wife, relating to the observation of the eclipse, his interview with the king of sweden, &c., and his visit to the pumping engines at haarlem: _july 28, half-past 10, morning_. the weather is at present most perfectly doubtful. nearly the whole sky is closely covered, yet there is now and then a momentary gleam of sun. the chances are greatly against much of the eclipse being seen. all is arranged to carry off the telescope, &c., at 11: they can be carted to the foot of the hill, and we have made out a walking-pass then to the top. we are to dine with mr dickson afterwards. _july 28, 10 at night_. well we have had a glorious day. as soon as we started, the weather began to look better. we went up the hill and planted my telescope, and the sky shewed a large proportion of blue. at first i placed the telescope on the highest rock, but the wind blew almost a gale, and shook it slightly: so i descended about 8 feet to one side. (the power of doing this was one of the elements in my choice of this station, which made me prefer it to the high hill beyond the river.) the view of scenery was inexpressibly beautiful. the beginning of eclipse was well seen. the sky gradually thickened from that time, so that the sun was in whitish cloud at the totality, and barely visible in dense cloud at the end of the eclipse. the progress of the eclipse brought on the wonderful changes that you know: just before the totality i saw a large piece of blue sky become pitch black; the horror of totality was very great; and then flashed into existence (i do not know how) a broad irregular corona with red flames _instantly seen_ of the most fantastic kind. the darkness was such that my assistant had very great trouble in reading his box chronometer. (a free-hand explanatory diagram is here given.) some important points are made out from this. 1st the red flames certainly belong to the sun. 2nd they certainly are in some instances detached. 3rd they are sometimes quite crooked. 4th they seem to be connected with spots. the corona was brilliant white. one star brilliant: i believe venus. i had no time to make observations of polarization, &c., although prepared. when the totality was more than half over i looked to n. and n.w., and in these regions there was the fullest rosy day-break light. after the sun-light reappeared, the black shadow went travelling away to the s.e. exactly like the thunder-storm from the main. the day then grew worse, and we came home here (after dinner) in pouring rain. stockholm, _1851, aug. 5_. i then by appointment with sir edmund lyons went with him to the minister for foreign affairs, baron stjerneld, who received me most civilly. my business was to thank him for the orders which had been given to facilitate the landing of our telescopes, &c., &c. he was quite familiar with the names of my party, humphreys milaud, &c., so that i trust they have been well received (i have had no letter). he intimated, i suppose at sir e. lyons's suggestion, that perhaps king oscar might wish to see me, but that it would not be on tuesday. so i replied that i was infinitely flattered and he said that he would send a message to sir e. lyons by tuesday evening. now all this put me in a quandary: because i wanted to see upsala, 47 miles off: and the steamboats on the mã¤lar only go in the morning and return in the morning: and this was irreconcileable with waiting for his majesty's appointment which might be for wednesday morning. so after consultation sir e. lyons put me in the hands of a sort of courier attached to the embassy, and he procured a calã¨che, and i posted to upsala yesterday afternoon (knocking the people up at 11 at night) and posted back this afternoon. and sure enough a message has come that the king expects me at 11 to-morrow morning. posting of course is much dearer than steam-boat travelling, but it is cheap in comparison with england: two horses cost 1s. for nearly 7 miles. at upsala there is a very good old cathedral, i suppose the only one in sweden: and many things about the university which interested me. i sent my card to professor fries, and he entirely devoted himself to me: but imagine our conversation--he spoke in _latin_ and i in french: however we understood each other very well. it is on the whole a dreary country except where enlivened by lakes: some parts are pine forests and birch forests, but others are featureless ground with boulder stones, like the worst part of the highlands. _august 6, wednesday, 3 o'clock_. i rigged myself in black trowsers and white waistcoat and neckcloth this morning. sir edmund lyons called. baron wrede called on me: he had observed the eclipse at calmar and brought his drawing, much like mine. he conducted me to the palace. the minister for foreign affairs came to me. in the waiting-room i was introduced to the lieutenant-governor of christianstad, who had had the charge of humphreys and milaud. he had placed a _guard of soldiers_ round them while they were observing. they saw the eclipse well. captain blackwood went to helsingborg instead of bornholm, and saw well. i am sorry to hear that it was cloudy at christiania, mr dunkin's station. i heard some days ago that hind had lost his telescope, but i now heard a very different story: that he landed at ystad, and found a very bad hotel there: that he learnt from murray that the hotels at carlscrona (or wherever he meant to go) were much worse; and so he grew faint at heart and turned back. i was summoned in to the king and presented by the minister (stjerneld), and had a long conversation with him: on the eclipse, the arc of meridian, the languages, and the universities. we spoke in french. then baron wrede went with me to the rittershus (house of lords or nobles) in session, and to the gallery of scandinavian antiquities, which is very remarkable: the collection of stone axes and chisels, bronze do., iron do., ornaments, &c. is quite amazing. i was struck with seeing specimens from a very distant age of the maid of norway's brooch: the use of which i explained to the director. i dined and drove out with sir e. lyons, and called at the houses of the baron stjerneld and of the norwegian minister baron duã«, and had tea at the latter. most of these people speak english well, and they seem to live in a very domestic family style. i should soon be quite at home here: for i perceive that my reception at court, &c., make people think that i am a very proper sort of person. * * * * * the extract concerning his visit to the pumping-engines at haarlem is as follows: leyden, _1851, august 20, wednesday_. i went to see the great north holland canal, and went a mile or two in a horse-drawn-boat upon it: a very comfortable conveyance. saw windmills used for sawing timber and other purposes, as well as some for grinding and many for draining. yesterday at half-past one i went by railway to haarlem. i did not look at anything in the town except going through it and seeing that it is a curious fantastic place, but i drove at once to the burgomaster to ask permission to visit one of the three great pumping engines for draining the immense haarlem lake, and then drove to it. imagine a round tower with a steam-cylinder in its center; and the piston which works up-and-down, instead of working one great beam as they usually do, works _eight_, poking out on different sides of the round tower, and each driving a pump 6 feet in diameter. i am glad to have seen it. then by railway here. * * * * * 1852 "galvanic communication was now established with lewisham station (thus giving power of communicating with london, deal, &c.).--from the report to the board of visitors it appears that, in the case of the transit circle, the azimuth of the instrument as determined by opposite passages of the pole star had varied four seconds; and in the case of the altazimuth, there was a discordance in the azimuthal zeros of the instrument, as determined from observations of stars. in both cases it was concluded that the discordances arose from small movements of the ground.--under the head of 'general remarks' in the report, the following paragraph occurs: 'it will be perceived that the number of equatoreal observations made here at present is small: and that they are rarely directed to new comets and similar objects which sometimes excite considerable interest. this omission is intentional. it is not because the instrumental means are wanting (for our equatoreals, though not comparable to those of either cambridge, or of pulkowa, are fully equal to those usually directed to such objects), but it is because these observations are most abundantly supplied from other observatories, public and private, and because the gain to those observations from our taking a part in them would, probably, be far less than the loss to the important class of observations which we can otherwise follow so well. moreover, i am unwilling to take any step which could be interpreted as attempting to deprive the local and private observatories of honours which they have so nobly earned. and, finally, in this act of abstinence, i am desirous of giving an example of adhesion to one principle which, i am confident, might be extensively followed with great advantage to astronomy:--the principle of division of labour.'--discoveries of small planets were now not infrequent: but the only one of interest to me is melpomene, for the following reason. on 1852 june 24 i lost my most dear, amiable, clever daughter elizabeth: she died at southampton, two days after landing from madeira. on that evening mr hind discovered the planet; and he requested me to give a name. i remembered horace's 'praecipe lugubres cantus, melpomene,' and cowley's 'i called the buskin'd muse melpomene and told her what sad story i would write,' and suggested melpomene, or penthos: melpomene was adopted.--the first move about the deal time ball was in a letter from commander baldock to the admiralty, suggesting that a time ball, dropped by galvanic current from greenwich, should be attached to one of the south foreland lighthouses. the admiralty sent this for my report. i went to the place, and i suggested in reply (nov. 15th) that a better place would be at an old signal station on the chalk downs. the decisive change from this was made in 1853.--as the result of my examination and enquiries into the subject of sympathetic clocks, i established 8 sympathetic clocks in the royal observatory, one of which outside the entrance gate had a large dial with shepherd's name as patentee. exception was taken to this by the solicitor of a mr bain who had busied himself about galvanic clocks. after much correspondence i agreed to remove shepherd's name till bain had legally established his claim. this however was never done: and in 1853 shepherd's name was restored.--in nov. 1851, denison had consented to join me in the preparation of the westminster clock. in feb. 1852 we began to have little disagreements. however on apr. 6th i was going to madeira, and requested him to act with full powers from me.--i communicated to the royal society my paper on the eclipses of agathocles, thales, and xerxes.--in the british association, i had presided at the ipswich meeting in 1851, and according to custom i ought to attend at the 1852 meeting (held at belfast) to resign my office. but i was broken in spirit by the death of my daughter, and the thing generally was beyond my willing enterprise. i requested sir roderick murchison to act generally for me: which he did, as i understood, very gracefully.--in this year a proposal was made by the government for shifting all the meeting rooms of the scientific societies to kensington gore, which was stoutly resisted by all, and was finally abandoned." of private history: "i was at playford in january, and went thence to chester on the enquiry about the tides of the dee; and made excursions to halton castle and to holyhead.--from apr. 8th to may 14th i was on the voyage to and from madeira, and on a short visit to my wife and daughter there.--on june 23rd i went to southampton to meet my wife and daughter just landed from madeira: on june 24th my dear daughter elizabeth died: she was buried at playford on june 29th.--i was at playford also in july and december.--from sept. 16th to 24th i went to cumberland, viã¢ fleetwood and peel." 1853 "on may 3rd 1853 i issued an address to the individual members of the board of visitors, proposing the extension of the lunar reductions from 1830. from this it appears that 'through the whole period (from 1830 to 1853), the places of the moon, deduced from the observations, are compared with the places computed in the nautical almanac: that is, with burckhardt's tables, which have been used for many years in computing the places of the nautical almanac.......very lately, however, mr adams has shewn that burckhardt's parallax is erroneous in formula and is numerically incorrect, sometimes to the amount of seven seconds. in consequence of this, every reduction of the observations of the moon, from 1830 to the present time, is sensibly erroneous. and the error is of such a nature that it is not easy, in general, to introduce its correction by any simple process.... the number of observations to the end of 1851 (after which time the parallax will be corrected in the current reductions) is about 2560. an expense approaching to _â£400_ might be incurred in their reduction.' subsequently i made application to the admiralty, and the _â£400_ was granted on dec. 12th.--in the report to the visitors it is stated that with regard to the transit circle, changes are under contemplation in its reflection-apparatus: one of these changes relates to the material of the trough. 'several years ago, when i was at hamburgh, my revered friend prof. schumacher exhibited to me the pacifying effect of a copper dish whose surface had been previously amalgamated with quicksilver.......the rev. charles pritchard has lately given much attention to this curious property of the metals, and has brought the practical operation of amalgamation to great perfection. still it is not without difficulty, on account of a singular crystallization of the amalgam.'--with regard to the chronograph, the report states: 'the barrel apparatus for the american method of observing transits is not yet brought into use.... i have, however, brought it to such a state that i am beginning to try whether the barrel moves with sufficient uniformity to be itself used as the transit clock. this, if perfectly secured, would be a very great convenience, but i am not very sanguine on that point.'--a change had been made in the electrometer-apparatus: 'a wire for the collection of atmospheric electricity is now stretched from a chimney on the north-west angle of the leads of the octagon room to the electrometer pole.... there appears to be no doubt that a greater amount of electricity is collected by this apparatus than by that formerly in use.'--as regards the magnetical observations: 'the visitors at their last meeting, expressed a wish that some attempt should be made to proceed further in the reduction or digest of the magnetical results, if any satisfactory plan could be devised. i cannot say that i have yet satisfied myself on the propriety of any special plan that i have examined.... i must, however, confess that, in viewing the capricious forms of the photographic curves, my mind is entirely bewildered, and i sometimes doubt the possibility of extracting from them anything whatever which can be considered trustworthy.'--great progress had been made with the distribution of time. 'the same normal clock maintains in sympathetic movement the large clock at the entrance gate, two other clocks in the observatory, and a clock at the london bridge terminus of the south-eastern railway.... it sends galvanic signals every day along all the principal railways diverging from london. it drops the greenwich ball, and the ball on the offices of the electric telegraph company in the strand;... all these various effects are produced without sensible error of time; and i cannot but feel a satisfaction in thinking that the royal observatory is thus quietly contributing to the punctuality of business through a large portion of this busy country. i have the satisfaction of stating to the visitors that the lords commissioners of the admiralty have decided on the erection of a time-signal ball at deal, for the use of the shipping in the downs, to be dropped every day by a galvanic current from the royal observatory. the construction of the apparatus is entrusted to me. probably there is no roadstead in the world in which the knowledge of true time is so important.'--the report includes an account of the determination of the longitude of cambridge observatory by means of galvanic signals, which appear to have been perfectly successful.--under the head of general remarks the following passage appears: 'the system of combining the labour of unattached computers with that of attached assistants tends materially to strengthen our powers in everything relating to computation. we find also, among the young persons who are engaged merely to serve as computers, a most laudable ambition to distinguish themselves as observers; and thus we are always prepared to undertake any observations which may be required, although necessarily by an expenditure of strength which would usually be employed on some other work.'--considerable work was undertaken in preparing a new set of maps of our buildings and grounds.--on apr. 23rd there was a small fire in the magnetic observatory, which did little mischief.--in december i wrote my description of the transit circle.--lieut. stratford, the editor of the nautical almanac, died, and there was some competition for the office. i was willing to take it at a low rate, for the addition to my salary: mr main--and i think mr glaisher--were desirous of exchanging to it: prof. adams was anxious for it. the admiralty made the excellent choice of mr hind.--in october faraday and i, at lothbury, witnessed some remarkable experiments by mr latimer clark on a galvanic current carried four times to and from manchester by subterranean wires (more than 2000 miles) shewing the retardation of visible currents (at their maximum effect) and the concentration of active power. i made investigations of the velocity of the galvanic current.--i was engaged on the preliminary enquiries and arrangements for the deal time ball.--with respect to the westminster clock; an angry paper was issued by mr vulliamy. in october i expostulated with denison about his conduct towards sir charles barry: on november 7th i resigned.--on feb. 11th i was elected president of the royal astronomical society.--in the royal institution i lectured on the ancient eclipses.--on dec. 15th i was elected to the academy of brussels.--after preliminary correspondence with sir w. molesworth (first commissioner of works, &c.) and sir charles barry (architect of the westminster palace), i wrote, on may 14th, to mr gladstone about depositing the four parliamentary copies of standards, at the royal observatory, the royal mint, the royal society, and within a wall of westminster palace. mr gladstone assented on june 23rd.--on mar. 26th i wrote to mr gladstone, proposing to take advantage of the new copper coinage for introducing the decimal system. i was always strenuous about preserving the pound sterling. on may 10th i attended the committee of the house of commons on decimal coinage: and in may and september i wrote letters to the athenaeum on decimal coinage.--i had always something on hand about tides. a special subject now was, the cry about intercepting the tidal waters of the tyne by the formation of the jarrow docks, in jarrow slake; which fear i considered to be ridiculous." of private history: "from jan. 15th to 24th i was at playford.--on mar. 4th i went to dover to try time-signals.--from june 24th to aug. 6th i was at little braithwaite near keswick, where i had hired a house, and made expeditions with members of my family in all directions. on july 28th i went, with my son wilfrid, by workington and maryport to rose castle, the residence of bishop percy (the bishop of carlisle), and on to carlisle and newcastle, looking at various works, mines, &c.--on dec. 24th i went to playford." 1854 the chronograph barrel-apparatus for the american method of transits had been practically brought into use: "i have only to add that this apparatus is now generally efficient. it is troublesome in use; consuming much time in the galvanic preparations, the preparation of the paper, and the translation of the puncture-indications into figures. but among the observers who use it there is but one opinion on its astronomical merits--that, in freedom from personal equation and in general accuracy, it is very far superior to the observations by eye and ear."--the printing and publication of the observations, which was always regarded by airy as a matter of the first importance, had fallen into arrear: "i stated in my last report that the printing of the observations for 1852 was scarcely commenced at the time of the last meeting of the visitors. for a long time the printing went on so slowly that i almost despaired of ever again seeing the observations in a creditable state. after a most harassing correspondence, the printers were at length persuaded to move more actively, ... but the volume is still very much behind its usual time of publication."--"the deal time-ball has now been erected by messrs maudslays and field, and is an admirable specimen of the workmanship of those celebrated engineers. the galvanic connection with the royal observatory (through the telegraph wires of the south eastern railway) is perfect. the automatic changes of wire-communications are so arranged that, when the ball at deal has dropped to its lowest point, it sends a message to greenwich to acquaint me, not with the time of the beginning of its fall (which cannot be in error) but with the fact that it has really fallen. the ball has several times been dropped experimentally with perfect success; and some small official and subsidiary arrangements alone are wanting for bringing it into constant use."--the operations for the galvanic determination of the longitude of brussels are described, with the following conclusion: "thus, about 3000 effective signals were made, but only 1000 of these were admissible for the fundamental objects of the operation. the result, i need scarcely remark, claims a degree of accuracy to which no preceding determination of longitude could ever pretend. i apprehend that the probable error in the difference of time corresponds to not more than one or two yards upon the earth's surface.--a careful scheme had been arranged for the determination of the longitude of lerwick, but 'unfortunately, the demand for chronometers caused by our large naval armament has been so considerable that i cannot reckon on having at my disposal a sufficient number to carry on this operation successfully; and i have, therefore, unwillingly deferred it to a more peaceful time.'--the covering stone of halley's tomb in lee churchyard was much shattered, and i applied to the admiralty for funds for its complete restoration: these were granted on feb. 3rd.--in this year, under my cognizance, _â£100_ was added to the hansen grant.--i had much correspondence and work in connection with the printing of maclear's work at the cape of good hope. in june, all accounts, &c. about the transit circle were closed at the admiralty, and the instrument was completely mounted at the cape.--dr scoresby (who in his own way was very imperious) had attacked my methods of correcting the compass in iron ships: i replied in a letter to the athenaeum on oct. 17th.--i made enquiries about operations for determining the longitude of vienna, but was utterly repelled by the foreign telegraph offices.--in the royal astronomical society; i prepared the address on presenting the medal to rã¼mker.--in melbourne university: the first letter received was from the chancellor of the university dated jan. 26th, requesting that sir john herschel, prof. malden, mr lowe (subsequently chancellor of the exchequer), and i would select professors. we had a great deal of correspondence, meetings, examination of testimonials, &c., and on august 14th we agreed on wilson, rowe, mccoy, and hearn.--on feb. 17th i received the prussian order of merit.--i had correspondence with the treasury on the scale to be adopted for the maps of the british survey. i proposed 1/3000, and for some purposes 1/600.--i printed a paper on the deluge, in which i shewed (i believe to certainty) that the deluge of genesis was merely a destructive flood of the nile.--being well acquainted with the mountains of cumberland, i had remarked that a 'man' or cairn of stones erected by the ordnance surveyors on the great gable had covered up a curious natural stone trough, known as one of the remarkable singularities of the country. this year, without giving any notice to the ordnance surveyors, i sent two wallers from borrowdale to the mountain top, to remove the 'man' about 10 feet and expose the trough. sir henry james afterwards approved of my act, and refunded the expense.--i investigated the optical condition of an eye with conical cornea. "the harton colliery experiment: i had long wished to repeat the experiment which i had attempted unsuccessfully in 1826 and 1828, of determining by pendulum-vibrations the measure of gravity at the bottom of a mine. residing near keswick this summer, and having the matter in my mind, i availed myself of an introduction from dr leitch to some gentlemen at south shields, for inspection of the harton colliery. i judged that it would answer pretty well. i find that on aug. 11th i wrote to mr anderson (lessee of the mine), and on the same day to the admiralty requesting authority to employ a greenwich assistant, and requesting _â£100_ for part payment of expenses. on august 16th the admiralty assent. there were many preparations to be made, both personal and instrumental. my party consisted of dunkin (superintendant), ellis, criswick, simmons, pogson, and rã¼mker: i did not myself attend the detail of observations. the observations began on oct. 2nd and ended on oct. 21st: supplementary observations were subsequently made at greenwich for examining the coefficient of temperature-correction. on oct. 24th i gave a lecture at south shields on the whole operation. in 'punch' of nov. 18th there was an excellent semi-comic account of the experiment, which as i afterwards found was written by mr percival leigh." of private history: "on jan. 18th i returned from playford. from mar. 10th to 13th i was at deal, and visited sir john herschel at hawkhurst.--from june 28th to aug. 7th i was staying with my family at the grange, in borrowdale near keswick: and also made an expedition to penrith, carlisle, newcastle, jarrow, &c.; and descended the harton pit.--in september and also in october i was at south shields on the harton experiments.--from dec. 14th to 18th i was at cambridge, and on the 26th i went to playford." the following letter, written in answer to a lady who had asked him to procure permission from lord rosse for her to observe with his telescope, is characteristic: royal observatory, greenwich. _1854, september 20_. dear madam, the state of things with regard to lord rosse's telescope is this. if a night is fine, it is wanted for his use or for the use of professional astronomers. if it is not fine, it is of no use to anybody. now considering this, and considering that the appropriation of the telescope on a fine night to any body but a technical astronomer is a misapplication of an enormous capital of money and intellect which is invested in this unique instrument--it is against my conscience to ask lord rosse to place it at the service of any person except an experienced astronomer. no introduction, i believe, is necessary for seeing it in the day-time. the instrument stands unenclosed in the castle demesne, to which strangers are admitted without question, i believe............... faithfully yours, g.b. airy. 1855 "on may 9th it was notified to me (i think through the hydrographer) that the admiralty were not unwilling to increase my salary. i made application therefore; and on jan. 21st 1856 sir charles wood notified to me that the admiralty consented to have it raised from _â£800_ to _â£1000_.--in the report to the board of visitors it appears that 'at the instance of the board of trade, acting on this occasion through a committee of the royal society, a model of the transit circle (with the improvement of perforated cube, &c. introduced in the cape transit circle) has been prepared for the great exhibition at paris.'--under the head of reduction of astronomical observations it is stated that 'during the whole time of which i have spoken, the galvanic-contact method has been employed for transits, with the exception of a few days, when the galvanic apparatus was out of order. from the clock errors, i have deduced the personal equations of the observers in our usual way.... the result is that the magnitude of the personal equations in the galvanic-touch method is not above half of that in the eye and ear method.'--with regard to the reduction of the magnetical observations, 'i have not yet felt sufficiently satisfied with any proposed method of discussing the magnetic results to devote any time to their further treatment.'--'the time-signal ball at deal was brought into regular use at the beginning of the present year. in a short time, however, its action was interrupted, partly by derangement of the apparatus, and partly by the severity of the weather, which froze the sulphuric acid to the state of jelly. i sent an assistant and workman to put it in order, and since that time it has generally acted very well.--application has been made to me from one of the important offices of government (the post office) for the galvanic regulation of their clocks.--on considering the risks to which various galvanic communications are liable, and the financial necessity for occupying wires as little as possible, i perceived that it was necessary to devise constructions which should satisfy the following conditions. first, that a current sent once a day should suffice for adjusting the clock, even if it had gone ten or more seconds wrong. secondly, that an occasional failure of the current should not stop the clock. i have arranged constructions which possess these characters, and the artist (mr c. shepherd) is now engaged in preparing estimates of the expense. i think it likely that this may prove to be the beginning of a very extensive system of clock regulation."--with respect to the operations for determining the longitude of paris, it is stated that, "the whole number of days of signal transmission was eighteen, and the whole number of signals transmitted was 2530. the number of days considered available for longitude, in consequence of transits of stars having been observed at both observatories, was twelve, and the number of signals was 1703. very great care was taken on both sides, for the adjustments of the instruments. the resulting difference of longitude, 9m. 20.63s., is probably very accurate. it is less by nearly 1s. of time than that determined in 1825 by rocket-signals, under the superintendance of sir john herschel and col. sabine. the time occupied by the passage of the galvanic current appears to be 1/12th of a second."--with regard to the pendulum experiments in the harton colliery, after mentioning that personal assistance had been sought and obtained from the observatories of cambridge, oxford, durham, and red hill, the report states that "the experiments appear to have been in every point successful, shewing beyond doubt that gravity is increased at the depth of 1260 feet by 1/10000th part. i trust that this combination may prove a valuable precedent for future associations of the different observatories of the kingdom, when objects requiring extensive personal organization shall present themselves."--on oct. 18th the astronomer royal printed an address to the individual members of the board of visitors on the subject of a large new equatoreal for the observatory. after a brief statement of the existing equipment of the observatory in respect of equatoreal instruments, the address continues thus: "it is known to the visitors that i have uniformly objected to any luxury of extrameridional apparatus, which would materially divert us from a steady adherence to the meridional system which both reason and tradition have engrafted on this observatory. but i feel that our present instruments are insufficient even for my wishes; and i cannot overlook the consideration that due provision must be made for future interests, and that we are nearer by twenty years to the time when another judgment must decide on the direction which shall be given to the force of the observatory."--"in august i had some correspondence about the egyptian wooden astronomical tablets with mr gresswell and others: they were fully examined by mr ellis.--in this year i was much engaged on schemes for compasses, and in june i sent my paper on discussions of ships' magnetism to the royal society.--on dec. 6th the mast of the observatory time-ball broke, and the ball fell in the front court.--on aug. 4th my valued friend mr sheepshanks died; and on aug. 14th i went to london to see the standard bars as left by him. afterwards, on oct. 25th i went to reading to collect the papers about standards left by mr sheepshanks.--i made a mechanical construction for euclid i. 47, with which i was well satisfied.--on apr. 13th i joined a deputation to the chancellor of the exchequer (sir g. cornewall lewis) on decimal coinage." of private history: "i was at playford for a large part of january.--on mar, 26th i went to reading, to visit mr sheepshanks, and afterwards to silchester and hereford.--on june 21st i went with my wife and two eldest sons to edinburgh and other places in scotland, but residing principally at oban, where i hired a house. amongst other expeditions, i and my son wilfrid went with the 'pharos' (northern lights steamer) to the skerry vohr lighthouse, &c. i also visited newcastle, &c., and returned to greenwich on aug. 2nd.--from oct. 12th to 17th i was at cambridge.--on dec. 24th i went to playford." chapter vii. at greenwich observatory--1856 to 1866. 1856 "in the report to the visitors there is an interesting account of the difficulties experienced with the reflex zenith tube in consequence of the tremors of the quicksilver transmitted through the ground. attempts were made to reduce the tremor by supporting the quicksilver trough on a stage founded at a depth of 10 feet below the surface, but it was not in the smallest degree diminished, and the report states that 'the experience of this investigation justifies me in believing that no practicable depth of trench prevents the propagation of tremor when the soil is like that of greenwich hill, a gravel, in all places very hard, and in some, cemented to the consistency of rock.'--with respect to the regulation of the post office clocks, 'one of the galvanic clocks in the post office department, lombard street, is already placed in connection with the royal observatory, and is regulated at noon every day ... other clocks at the general post office are nearly prepared for the same regulation, and i expect that the complete system will soon be in action.'--under the head of general remarks a careful summary is given of the work of the observatory, and the paragraph concludes as follows: 'lastly there are employments which connect the scientific observatory with the practical world; the distribution of accurate time, the improvement of marine time-keepers, the observations and communications which tend to the advantage of geography and navigation, and the study, in a practical sense, of the modifications of magnetism; a careful attention to these is likely to prove useful to the world, and conducive to the material prosperity of the observatory: and these ought not to be banished from our system.'--in september i prepared the first specification for the building to carry the s.e. dome.--in september, learning that hansen's lunar tables were finished in manuscript, i applied to lord clarendon and they were conveyed to me through the foreign office: in october i submitted to the admiralty the proposal for printing the tables, and in november i learned that the treasury had assented to the expense.--lieut. daynou's eclipses and occultations for longitudes of points in south africa, observed in 1854 and 1855, were calculated here in this year.--on feb. 16th i made my first application to sir c. wood (first lord of the admiralty) for assistance to c. piazzi smyth to carry out the teneriffe experiment: grounding it in part on the failure of attempts to see the solar prominences. he gave encouragement, and on mar. 18th i transmitted piazzi smyth's memorial to the admiralty: on may 2nd the admiralty authorized an expense of _â£500_. i drew up suggestions.--the sheepshanks fund: after the death of my friend richard sheepshanks, his sister miss anne sheepshanks wished to bestow some funds in connection with the university of cambridge, trinity college, and astronomy, to which his name should be attached. there must have been some conversation with me, but the first letter is one from de morgan in august. in september i had a conversation with miss sheepshanks, and sent her my first draft of a scheme, to which she assented. on sept. 30th i wrote to whewell (master of trinity) who was much trusted by miss sheepshanks: he consented to take part, and made some suggestions. there was further correspondence, but the business did not get into shape in this year.--in connection with the correction of the compass in iron ships: i discussed the observations made in the voyage of the royal charter. on feb. 13th i proposed to the admiralty a system of mounting the compasses with adjustable magnets, and it was ordered to be tried in the trident and transit.--in february i reported to the admiralty that the deal time-ball had been successful, and i proposed time-balls at portsmouth, plymouth, and sheerness. there was much correspondence in various directions about portsmouth and devonport, and in march i went to devonport and specially examined mount wise and the devonport column.--i had correspondence with sir howard douglas about the sea breaking over the unfinished dover pier. i have an idea that this followed evidence given by me to a harbour commission, in which i expressed as a certainty that the sea will not be made to break by a vertical wall." of private history: "i returned from playford on jan. 18th.--from june 16th to august 5th i was, with my son wilfrid, on an expedition to south italy and sicily: on our return from sicily, we remained for three days ill at marseilles from a touch of malaria.--on dec. 22nd i went to playford.--in acknowledgment of the pleasure which i had derived from excursions in the cumberland passes, i made a foot-bridge over a troublesome stream on the pass of the sty head." 1857 "in the report to the visitors, when on the subject of the altazimuth, the following paragraph occurs: 'i alluded in a preceding section to the cutting away of a very small portion of one of the rays of the three-armed pier which carries the altazimuth. the quality of the brickwork is the best that i have ever seen, and not a single brick was disturbed beyond those actually removed. yet the effect was to give the altazimuth an inclination of about 23". this inclination evidently depends on the elasticity of the brickwork.'--with reference to the new s.e. equatoreal the report states that 'the support of the north or upper end of the polar axis has been received, and is planted within the walls of the building in a position convenient for raising it to its ultimate destination. it is one piece of cast-iron, and weighs nearly 5 tons.'--small changes as previously mentioned had been noticed with regard to the zero of azimuth of the transit circle, and the report states that 'in regard to the azimuth of the transit circle, and the azimuth of its collimator, mr main has brought together the results of several years, and the following law appears to hold. there is a well-marked annual periodical change in the position of the transit circle, the southerly movement of the eastern pivot having its minimum value in september, and its maximum in march, the extreme range being about 14 seconds; and there is a similar change, but of smaller amount, in the position of the collimator. i cannot conjecture any cause for these changes, except in the motion of the ground. there is also a well-marked connection between the state of level of the axis and the temperature. the eastern pivot always rises when the temperature rises, the extreme range being about 6 seconds. i cannot offer any explanation of this.'--under the head of extraneous works the report states that 'the british government had for some years past contributed by pecuniary grants to the preparation of prof. hansen's lunar tables. in the last winter they undertook the entire expense of printing a large impression of the tables. the reading of the proof-sheets (a very considerable labour) has been effected entirely at the observatory. i may take this opportunity of stating that the use of these tables has enabled me, as i think, incontestably to fix the capture of larissa to the date b.c. 557, may 19. this identification promises to prove valuable, not merely for its chronological utility, but also for its accurate determination of an astronomical epoch, the point eclipsed being exactly known, and the shadow having been very small.'--in april i gave a lecture to the royal astronomical society on the methods available through the next 25 years for the determination of the sun's parallax.--dr livingstone's observations for african longitudes were computed at the observatory.--the admiralty enquire of me about the feasibility of adopting piazzi smyth's construction for steadying telescopes on board ship: i gave a report, of mixed character, on the whole discouraging.--i had correspondence with g.p. bond and others about photographing the stars and moon.--on feb. 17th piazzi smyth's books, &c. relating to the teneriffe experiment were sent to me: i recommended that an abridged report should be sent to the royal society.--respecting the sheepshanks fund: there was correspondence with miss sheepshanks and whewell, but nothing got into shape this year: miss sheepshanks transferred to me _â£10,000_ lying at overend and gurney's.--in november experiments were made for the longitude of edinburgh, which failed totally from the bad state of the telegraph wire between deptford and the admiralty.--in june the first suggestion was made to me by capt. washington for time-signals on the lizard point: which in no long time i changed for the start point.--the admiralty call for estimates for a time-ball at portsmouth: on receiving them they decline further proceeding.--i was engaged in speculations and correspondence about the atlantic submarine cable.--in the royal astronomical society, i presented memoirs and gave lectures on the three great chronological eclipses (agathocles, thales, larissa)."--on dec. 5th airy wrote to the vice-chancellor of the university of cambridge, objecting to the proposed changes regarding the smith's prizes--a subject in which he took much interest, and to which he ascribed great importance.--on apr. 27th i was in correspondence with g. herbert of the trinity house, about floating beacons.--in july i reported to the treasury on the swedish calculating engine (i think on the occasion of mr farr, of the registrar-general's office, applying for one).--in november i had correspondence about the launch of the great eastern, and the main drainage of london." of private history: "on jan. 14th i returned from playford.--from june 27th to aug. 5th i was travelling in scotland with my wife and two eldest sons, chiefly in the west highlands. on our return we visited mrs smith (my wife's mother) at brampton.--on dec. 26th i went to playford." 1858 "in the minutes of the visitors it is noted that the new queen's warrant was received. the principal change was the exclusion of the astronomer royal and the other observatory officers from the board.--in the report to the visitors it is stated that 'the papers of the board of longitude are now finally stitched into books. they will probably form one of the most curious collections of the results of scientific enterprise, both normal and abnormal, which exists.'--it appears that the galvanic communications, external to the observatory, had been in a bad state, the four wires to london bridge having probably been injured by a thunderstorm in the last autumn, and the report states that 'the state of the wires has not enabled us to drop the ball at deal. the feeble current which arrives there has been used for some months merely as giving a signal, by which an attendant is guided in dropping the ball by hand.'--regarding the new equatoreal the report states that 'for the new south-east equatoreal, the object-glass was furnished by messrs merz and son in the summer of last year, and i made various trials of it in a temporary tube carried by the temporary mounting which i had provided, and finally i was well satisfied with it. i cannot yet say that i have certainly divided the small star of gamma andromedae; but, for such a test, a combination of favourable circumstances is required. from what i have seen, i have no doubt of its proving a first-rate object-glass.'--on march 15th was an annular eclipse of the sun, for the observation of which i sent parties fully equipped to bedford, wellingborough, and market harborough. the observations failed totally in consequence of the bad weather: i myself went to harrowden near wellingborough.--respecting the altazimuth, the report states that with due caution as to the zero of azimuth 'the results of observation are extremely good, very nearly equal to those of the meridional instrument; perhaps i might say that three observations with the altazimuth are equivalent to two with the transit circle.'--respecting meteorological observations the report states that 'the observations of the maximum and minimum thermometers in the thames, interrupted at the date of the last report, have been resumed, and are most regularly maintained. regarding the thames as the grand climatic agent on london and its neighbourhood, i should much regret the suppression of these observations.'--after much trouble the longitude of edinburgh had been determined: 'the retard of the current is 0.04s very nearly, and the difference of longitudes 12m 43.05s, subject to personal equations.'--the report concludes thus: 'with regard to the direction of our labours, i trust that i shall always be supported by the visitors in my desire to maintain the fundamental and meridional system of the observatory absolutely intact. this, however, does not impede the extension of our system in any way whatever, provided that such means are arranged for carrying out the extension as will render unnecessary the withdrawal of strength from what are now the engrossing objects of the observatory.'--i had much correspondence on comets, of which donati's great comet was one: the tail of this comet passed over arcturus on october 5th.--respecting the sheepshanks fund: in september i met whewell at leeds, and we settled orally the final plan of the scheme. on oct. 27th i saw messrs sharp, miss sheepshanks's solicitors, and drew up a draft of the deed of gift. there was much correspondence, and on nov. 20th i wrote to the vice-chancellor of cambridge university. a counter-scheme was proposed by dr philpott, master of st catharine's college. by arrangement i attended the council of the university on dec. 3rd, and explained my views, to which the council assented. on dec. 9th the senate accepted the gift of miss sheepshanks.--i had much correspondence throughout this year, with the treasury, herschel, sabine, and the royal society, about the continuation of the magnetic establishments. the reductions of the magnetic observations 1848-1857 were commenced in february of this year, under the direction of mr lucas, a computer who had been engaged on the lunar reductions.--in this year i came to a final agreement with the south eastern railway company about defining the terms of our connection with them for the passage of time signals. i was authorized by the admiralty to sign the 'protocol' or memorandum of agreement, and it was signed by the south eastern railway directors.--on aug. 28th i made my first proposal to sir john packington (first lord of the admiralty) for hourly time signals on the start point, and in september i went to the start to examine localities, &c. on dec. 23rd the admiralty declined to sanction it.--i presented to the royal society a paper about drawing a great-circle trace on a mercator's chart.--in october i gave a lecture on astronomy in the assembly room at bury.--on jan. 25th i was busied with my mathematical tracts for republication."--in this year airy published in the athenaeum very careful and critical remarks on the commissioners' draft of statutes for trinity college. he was always ready to take action in the interests of his old college. this paper procured him the warmest gratitude from the fellows of the college. of private history: "on jan. 23rd i returned from playford. from july 5th to aug. 6th i was on an expedition in switzerland with my two eldest sons. at paris we visited le verrier, and at geneva we visited gautier, de la rive, and plantamour. we returned by brussels.--on dec. 23rd i went to playford."--in this year was erected in playford churchyard a granite obelisk in memory of thomas clarkson. it was built by subscription amongst a few friends of clarkson's, and the negociations and arrangements were chiefly carried out by airy, who zealously exerted himself in the work which was intended to honour the memory of his early friend. it gave him much trouble during the years 1856 to 1858. here is a letter to the editor of the athenaeum on some other trinity matters: _1858, november 22_. dear sir, in the athenaeum of november 20, page 650, column 3, paragraph 4, there is an account of the erection of the statue of barrow in trinity college antechapel (cambridge) conceived in a spirit hostile to the university, and written in great ignorance of the facts. on the latter i can give the writer some information. the marquis of lansdowne, who was a trinity man and whose son was of trinity, intimated to the authorities of the college that he was desirous of placing in the antechapel a statue of _milton_. this, regard being had to the customs and the college-feelings of cambridge, was totally impossible. the antechapel of every college is sacredly reserved for memorials of the men of that college only; and milton was of christ's college. the marquis of lansdowne, on hearing this objection, left the choice of the person to be commemorated, to certain persons of the college, one of whom (a literary character of the highest eminence and a profound admirer of milton) has not resided in cambridge for many years. several names were carefully considered, and particularly one (not mentioned by your correspondent) of very great literary celebrity, but in whose writings there is ingrained so much of ribaldry and licentiousness that he was at length given up. finally the choice rested on barrow, not as comparable to milton, but as a person of reputation in his day and as the best who could be found under all the circumstances. cromwell never was mentioned; he was a member of sidney college: moreover it would have been very wrong to select the exponent of an extreme political party. but cromwell has i believe many admirers in cambridge, to which list i attach myself. i had no part in the negociations above mentioned, but i saw the original letters, and i answer for the perfect correctness of what i have stated. but as i am not a principal, i decline to appear in public. it is much to be desired, both for the athenaeum and for the public, that such an erroneous statement should not remain uncorrected. and i would suggest that a correction by the editor would be just and graceful, and would tend to support the athenaeum in that high position which it has usually maintained. i am, dear sir, yours very faithfully, g.b. airy. _hepworth dixon, esq._ 1859 "the report to the visitors states that 'the lunar reductions with amended elements (especially parallax) for correction of observations from 1831 to 1851 are now completed. it is, i think, matter of congratulation to the observatory and to astronomy, that there are now exhibited the results of uninterrupted lunar observations extending through more than a century, made at the same place, reduced under the same superintendence and on the same general principles, and compared throughout with the same theoretical tables.'--after reference to the great value of the greenwich lunar observations to prof. hansen in constructing his tables, and to the liberality of the british government in their grants to hansen, the report continues thus: 'a strict comparison of hansen's tables with the greenwich observations of late years, both meridional and extra-meridional, was commenced. the same observations had, in the daily routine of the observatory, been compared with the nautical almanac or burckhardt's tables. the result for one year only (1852) has yet reached me, but it is most remarkable. the sum of squares of residual errors with hansen's tables is only one-eighth part of that with burckhardt's tables. when it is remembered that in this is included the entire effect of errors and irregularities of observation, we shall be justified in considering hansen's tables as nearly perfect. so great a step, to the best of my knowledge, has never been made in numerical physical theory. i have cited this at length, not only as interesting to the visitors from the circumstance that we have on our side contributed to this great advance, but also because an innovation, peculiar to this observatory, has in no small degree aided in giving a decisive character to the comparison. i have never concealed my opinion that the introduction and vigorous use of the altazimuth for observations of the moon is the most important addition to the system of the observatory that has been made for many years. the largest errors of burckhardt's tables were put in evidence almost always by the altazimuth observations, in portions of the moon's orbit which could not be touched by the meridional instruments; they amounted sometimes to nearly 40" of arc, and they naturally became the crucial errors for distinction between burckhardt's and hansen's tables. those errors are in all cases corrected with great accuracy by hansen's tables.'--the report concludes with the following paragraph: 'with the inauguration of the new equatoreal will terminate the entire change from the old state of the observatory. there is not now a single person employed or instrument used in the observatory which was there in mr pond's time, nor a single room in the observatory which is used as it was used then. in every step of change, however, except this last, the ancient and traditional responsibilities of the observatory have been most carefully considered: and, in the last, the substitution of a new instrument was so absolutely necessary, and the importance of tolerating no instrument except of a high class was so obvious, that no other course was open to us. i can only trust that, while the use of the equatoreal within legitimate limits may enlarge the utility and the reputation of the observatory, it may never be permitted to interfere with that which has always been the staple and standard work here.'--concerning the sheepshanks fund: there was much correspondence about settling the gift till about feb. 21st. i took part in the first examination for the scholarship in october of this year, and took my place with the trinity seniority, as one of their number on this foundation, for some general business of the fund.--with respect to the correction of the compass in iron ships: i sent mr ellis to liverpool to see some practice there in the correction of the compass. in september i urged mr rundell to make a voyage in the great eastern (just floated) for examination of her compasses, and lent him instruments: very valuable results were obtained. mr archibald smith had edited scoresby's voyage in the royal charter, with an introduction very offensive to me: i replied fully in the athenaeum of nov. 7th.--the sale of gas act: an act of parliament promoted by private members of the house of commons had been passed, without the knowledge or recollection of the government. it imposed on the government various duties about the preparation of standards. suddenly, at the very expiration of the time allowed this came to the knowledge of government. on oct. 1st lord monteagle applied to me for assistance. on oct. 15th and 22nd i wrote to mr hamilton, secretary of the treasury, and received authority to ask for the assistance of prof. w.h. miller.--i made an examination of mr ball's eyes (long-sighted and short-sighted i think).--in february i made an analysis of the cambridge tripos examination, which i communicated to some cambridge residents." in a letter on this subject to one of his cambridge friends airy gives his opinion as follows: "i have looked very carefully over the examination papers, and think them on the whole very bad. they are utterly perverted by the insane love of problems, and by the foolish importance given to wholly useless parts of algebraical geometry. for the sake of these, every physical subject and every useful application of pure mathematics are cut down or not mentioned." this led to much discussion at cambridge. in this year the smith's prizes were awarded to the 4th and 6th wranglers. of private history: "on apr. 29th mrs smith (my wife's mother) died at brampton.--from july 4th to aug. 2nd i was in france (auvergne and the vivarais) with my two eldest sons. maclear travelled with us to paris.--on dec. 23rd i went to playford."--antiquities and historical questions connected with military movements had a very great attraction for airy. on his return from the expedition in france above-mentioned, he engaged in considerable correspondence with military authorities regarding points connected with the battle of toulouse. and in this year also he had much correspondence with the duke of northumberland concerning his map of the roman wall, and the military points relating to the same. 1860 "in june mr main accepted the office of radcliffe observer at oxford (mr johnson having died) and resigned the first assistancy at greenwich: in october mr stone was appointed first assistant.--at an adjourned meeting of the visitors on june 18th there were very heavy discussions on hansen's merits, and about the grant to him. papers were read from sir j. lubbock, babbage, south, whewell, and me. finally it was recommended to the government to grant _â£1000_ to hansen, which was paid to him.--in the report to the board of visitors the following remark occurs: 'the apparent existence of a discordance between the results of direct observations and reflection observations (after the application of corrections for flexure, founded upon observations of the horizontal collimator wires) to an extent far greater than can be explained by any disturbance of the direction of gravity on the quicksilver by its distance from the vertical, or by the attraction of neighbouring masses, perplexes me much.'--with respect to the discordance of dips of the dipping-needles, which for years past had been a source of great trouble and puzzle, the report states that 'the dipping-needles are still a source of anxiety. the form which their anomalies appear to take is that of a special or peculiar value of the dip given by each separate needle. with one of the 9-inch needles, the result always differs about a quarter of a degree from that of the others. i can see nothing in its mechanical construction to explain this.--reference is made to the spontaneous currents through the wires of telegraph companies, which are frequently violent and always occur at the times of magnetic storms, and the report continues 'it may be worth considering whether it would ever be desirable to establish in two directions at right angles to each other (for instance, along the brighton railway and along the north kent railway) wires which would photographically register in the royal observatory the currents that pass in these directions, exhibiting their indications by photographic curves in close juxtaposition with the registers of the magnetic elements.'--in connection with the reduction of the greenwich lunar observations from 1831 to 1851, the report states that 'the comparison of hansen's lunar tables with the greenwich observations, which at the last visitation had been completed for one year only, has now been finished for the twelve years 1847 to 1858. the results for the whole period agree entirely, in their general spirit, with those for the year 1852 cited in the last report. the greatest difference between the merits of burckhardt's and hansen's tables appears in the meridional longitudes 1855, when the proportion of the sum of squares of errors is as 31 (burckhardt) to 2 (hansen). the nearest approach is in the altazimuth latitudes 1854, when the proportion of the sum of squares of errors is as 12 (burckhardt) to 5 (hansen).'--a special address to the members of the board of visitors has reference to the proposals of m. struve for (amongst other matters) the improved determination of the longitude of valencia, and the galvanic determination of the extreme eastern station of the british triangles.--on sept. 13th i circulated amongst the visitors my remarks on a paper entitled 'on the polar distances of the greenwich transit-circle, by a. marth,' printed in the astronomische nachrichten; the paper by mr marth was an elaborate attack on the greenwich methods of observation, and my remarks were a detailed refutation of his statements.--on oct. 20th i made enquiry of sabine as to the advantage of keeping up magnetic observations. on oct. 22nd he wrote, avoiding my question in some measure, but saying that our instruments must be changed for such as those at kew (his observatory): i replied, generally declining to act on that advice.--in march and april i was in correspondence with mr cowper (first commissioner of works, &c.) about the bells of the westminster clock; also about the smoky chimneys of the various apartments of the palace. on apr. 21st i made my report on the clock and bells, 20 foolscap pages. i employed a professional musician to examine the tones of the bells.--in november i was writing my book on probable errors, &c.--i was engaged on the tides of kurrachee and bombay.--the first examination of navy telescopes was made for the admiralty. --hoch's paper on aberration appeared in the astronomische nachrichten. this (with others) led to the construction of the water-telescope several years later.--in september i wrote in the athenaeum against a notion of sir h. james on the effect of an upheaval of a mountain in changing the earth's axis. in october i had drawn up a list of days for a possible evagation of the earth's poles: but apparently nothing was done upon them. "in this year i was a good deal occupied for the lighthouse commission. on feb. 21st admiral hamilton (chairman) applied to me for assistance. in april i went to chance's factory in birmingham on this business. in may i made my report on the start lighthouse, after inspection with the commission. in june, with my son hubert, i visited the whitby lighthouses, and discovered a fault of a singular kind which most materially diminished their power. this discovery led to a general examination of lighthouses by the trinity board, to a modification of many, and to a general improvement of system. on june 25th i reported on the lights at calais, cap de valde, grisnez, south foreland, and north foreland. in august i had been to the north foreland again, and in september to calais and the cap d'ailly. in october i went with my son hubert to aberdeen to see the girdleness lighthouse. on nov. 10th i made a general report. "this was the year of the great total solar eclipse visible in spain. at my representation, the admiralty placed at my command the large steamship 'himalaya' to carry about 60 astronomers, british and foreign. some were landed at santander: i with many at bilbao. the eclipse was fairly well observed: i personally did not do my part well. the most important were mr de la rue's photographic operations. at greenwich i had arranged a very careful series of observations with the great equatoreal, which were fully carried out." the eclipse expedition to spain, shortly referred to above, was most interesting, not merely from the importance of the results obtained (and some of the parties were very fortunate in the weather) but from the character of the expedition. it was a wonderful combination of the astronomers of europe, who were all received on board the 'himalaya,' and were conveyed together to the coast of spain. the polyglot of languages was most remarkable, but the utmost harmony and enthusiasm prevailed from first to last, and this had much to do with the general success of the expedition. those who landed at bilbao were received in the kindest and most hospitable manner by mr c.b. vignoles, the engineer-in-chief of the bilbao and tudela railway, which was then under construction. this gentleman made arrangements for the conveyance of parties to points in the interior of the country which were judged suitable for the observation of the eclipse, and placed all the resources of his staff at the disposal of the expedition in the most liberal manner. the universal opinion was that very great difficulty would have been experienced without the active and generous assistance of mr vignoles. it is needless to say that the vote of thanks to mr vignoles, proposed by the astronomer royal during the return voyage, was passed by acclamation and with a very sincere feeling of gratitude: it was to the effect that 'without the great and liberal aid of mr c.b. vignoles, and the disinterested love of science evinced by him on this occasion, the success of the "himalaya" eclipse expedition could not have been ensured.' there is a graphic and interesting account of the reception of the party at bilbao given in the 'life of c.b. vignoles, f.r.s., soldier and civil engineer,' by o.j. vignoles, m.a. of private history: "on may 26th my venerable friend arthur biddell died. he had been in many respects more than a father to me: i cannot express how much i owed to him, especially in my youth.--from june 12th to 15th i visited the whitby lighthouses with my son hubert.--from july 6th to 28th i was in spain, on the 'himalaya' expedition, to observe the total eclipse: i was accompanied by my wife, my eldest son, and my eldest daughter.--from oct. 5th to 18th i went with my son hubert to aberdeen to see the girdleness lighthouse, making lateral trips to cumberland in going and returning.--on dec. 21st i went to playford." 1861 "in the report to the visitors there is great complaint of want of room. 'with increase of computations, we want more room for computers; with our greatly increased business of chronometers and time-distribution, we are in want of a nearly separate series of rooms for the time-department: we want rooms for book-stores; and we require rooms for the photographic operations and the computations of the magnetic department.'--the report gives a curious history of dr bradley's observations, which in 1776 had been transferred to the university of oxford, and proceeds thus: 'more lately, i applied (in the first instance through lord wrottesley) to the vice-chancellor, dr jeune, in reference to the possibility of transferring these manuscripts to the royal observatory.... finally, a decree for the transfer of the manuscript observations to the royal observatory, without any condition, was proposed to convocation on may 2nd, and was passed unanimously. and on may 7th my assistant, mr dunkin, was sent to oxford to receive them. and thus, after a delay of very nearly a century, the great work of justice is at length completed, and the great gap in our manuscript observations is at length filled up.'--with reference to the transit circle, it had been remarked that the collimators were slightly disturbed by the proximity of the gas-flames of their illuminators, and after various experiments as to the cause of it, the report proceeds thus: 'to my great surprise, i found that the disturbance was entirely due to the radiation of the flame upon a very small corner (about 16 square inches) of the large and massive stone on which the collimator is planted. the tin plates were subsequently shaped in such a manner as to protect the stone as well as the metal; and the disturbance has entirely ceased.' --regarding the large s.e. equatoreal, the report states that 'on the character of its object-glass i am now able to speak, first, from the examination of mr otto struve, made in a favourable state of atmosphere; secondly, from the examinations of my assistants (i have not myself obtained a sight of a test-object on a night of very good definition). it appears to be of the highest order. the small star of gamma andromedae is so far separated as to shew a broad dark space between its components. some blue colour is shewn about the bright planets.'--it is noted in the report that 'the equatoreal observations of the solar eclipse are completely reduced; and the results are valuable. it appears from them that the error in right ascension of burckhardt's lunar tables at the time of the eclipse amounted to about 38"; while that of hansen's (ultimately adopted by mr hind for the calculation of the eclipse) did not exceed 3".'--with regard to chronometers it is stated that 'by use of the chronometer oven, to which i have formerly alluded, we have been able to give great attention to the compensation. i have reason to think that we are producing a most beneficial effect on the manufacture and adjustment of chronometers in general.'--with regard to the cape of good hope observatory and survey, the admiralty enquire of me when the survey work will be completed, and i enquire of maclear 'how is the printing of your survey work?' in 1862 i began to press it strongly, and in 1863 very strongly.--i introduced a method (constantly pursued since that time at the royal observatory) for computing interpolations without changes of sign.--i had correspondence with herschel and faraday, on the possible effect of the sun's radiant heat on the sea, as explaining the curve of diurnal magnetic inequality. (that diurnal inequality was inferred from the magnetic reductions 1848-1857, which were terminated in 1860.)--regarding the proposal of hourly time-signals on the start point, i consulted telegraph engineers upon the practical points, and on dec. 21st i proposed a formal scheme, in complete detail. (the matter has been repeatedly brought before the admiralty, but has been uniformly rejected.)--i was engaged on the question of the bad ocular vision of two or three persons.--the british association meeting was held at manchester: i was president of section a. i gave a lecture on the eclipse of 1860 to an enormous attendance in the free trade hall." the following record of the lecture is extracted from dr e.j. routh's obituary notice of airy written for the proceedings of the royal society. "at the meeting of the british association at manchester in 1861, mr airy delivered a lecture on the solar eclipse of 1860 to an assembly of perhaps 3000 persons. the writer remembers the great free trade hall crowded to excess with an immense audience whose attention and interest, notwithstanding a weak voice, he was able to retain to the very end of the lecture....the charm of professor airy's lectures lay in the clearness of his explanations. the subjects also of his lectures were generally those to which his attention had been turned by other causes, so that he had much that was new to tell. his manner was slightly hesitating, and he used frequent repetitions, which perhaps were necessary from the newness of the ideas. as the lecturer proceeded, his hearers forgot these imperfections and found their whole attention rivetted to the subject matter." of private history: "on jan. 2nd there was a most remarkable crystallization of the ice on the flooded meadows at playford: the frost was very severe.--from june 20th to aug. 1st i was at the grange near keswick (where i hired a house) with my wife and most of my family.--from nov. 5th to 14th i was on an expedition in the south of scotland with my son wilfrid: we walked with our knapsacks by the roman road across the cheviots to jedburgh.--on dec. 21st i went to playford." 1862 "the report to the board of visitors states that 'a new range of wooden buildings (the magnetic offices) is in progress at the s.s.e. extremity of the magnetic ground. it will include seven rooms.'--also 'i took this opportunity (the relaying of the water-main) of establishing two powerful fire-plugs (one in the front court, and one in the magnetic ground); a stock of fire-hose adapted to the "brigade-screw" having been previously secured in the observatory.'--'two wires, intended for the examination of spontaneous earth-currents, have been carried from the magnetic observatory to the railway station in the town of greenwich. from this point one wire is to be led to a point in the neighbourhood of croydon, the other to a point in the neighbourhood of dartford. each wire is to be connected at its two extremities with the earth. the angle included between the general directions of these two lines is nearly a right angle.'--'the kew unifilar magnetometer, adapted to the determination of the horizontal part of terrestrial magnetic force in absolute measure, was mounted in the summer of 1861; and till 1862 february, occasional observations (14 in all) were taken simultaneously with the old and with the new instrument. the comparison of results shewed a steady but very small difference, not greater probably than may correspond to the omission of the inverse seventh powers of distance in the theoretical investigation; proving that the old instrument had been quite efficient for its purpose.'--great efforts had been made to deduce a law from the diurnal inequalities in declination and horizontal force, as shewn by the magnetic observations; but without success: the report states that 'the results are most amazing, for the variation in magnitude as well as in law. what cosmical change can be indicated by them is entirely beyond my power of conjecture.'--'i have alluded, in the two last reports, to the steps necessary, on the english side, for completing the great arc of parallel from valencia to the volga. the russian portion of the work is far advanced, and will be finished (it is understood) in the coming summer. it appeared to me therefore that the repetition of the measure of astronomical longitude between greenwich and valencia could be no longer delayed. two assistants of the royal observatory (mr dunkin and mr criswick) will at once proceed to valencia, for the determination of local time and the management of galvanic signals.'--'i now ask leave to press the subject of hourly time signals at the start point on the attention of the board, and to submit the advantage of their addressing the board of admiralty upon it. the great majority of outward-bound ships pass within sight of the start, and, if an hourly signal were exhibited, would have the means of regulating their chronometers at a most critical part of their voyage. the plan of the entire system of operations is completely arranged. the estimated expense of outfit is _â£2017_, and the estimated annual expense is _â£326_; both liable to some uncertainty, but sufficiently exact to shew that the outlay is inconsiderable in comparison with the advantages which might be expected from it. i know no direction of the powers of the observatory which would tend so energetically to carry out the great object of its establishment, viz. "the finding out the so much desired longitude at sea."'--the attention of the visitors is strongly drawn to the pressure on the strength of the observatory caused by the observation of the numerous small planets, and the paragraph concludes thus: 'i shall, however, again endeavour to effect a partition of this labour with some other observatory.'--a small fire having occurred in the magnetic observatory, a new building of zinc, for the operation of naphthalizing the illuminating gas, is in preparation, external to the observatory: and thus one of the possible sources of accidental fire will be removed.--miss sheepshanks added, through me, _â£2000_ to her former gift: i transferred it, i believe, to the master and seniors of trinity college."--in this year airy contributed to the royal society two papers, one "on the magnetic properties of hot-rolled and cold-rolled malleable iron," the other "on the strains in the interior of beams." he gave evidence before the select committee on weights and measures, and also before the public schools commission. in the latter part of 1862 a difference arose between airy and major-general sabine, in consequence of remarks made by the latter at a meeting of the committee of recommendations of the british association. these remarks were to the effect "that it is necessary to maintain the complete system of self-registration of magnetic phenomena at the kew observatory, because no sufficient system of magnetic record is maintained elsewhere in england"; implying pointedly that the system at the royal observatory of greenwich was insufficient. this matter was taken up very warmly by airy, and after a short and acrimonious correspondence with sabine, he issued a private address to the visitors, enclosing copies of the correspondence with his remarks, and requesting the board to take the matter of this attack into their careful consideration. this address is dated november 1862, and it was followed by another dated january 1863, which contains a careful reply to the various points of general sabine's attack, and concludes with a distinct statement that he (the astronomer royal) can no longer act in confidence with sabine as a member of the board of visitors. of private history: there were the usual short visits to playford at the beginning and end of the year.--from june 28th to aug. 5th he was in scotland (chiefly in the western highlands) with his wife and his sons hubert and osmund. in the course of this journey he visited the corryvreckan whirlpool near the island of scarba, and the following paragraph relating to this expedition is extracted from his journal: "landed in black mile bay, island of luing, at 10.30. here by previous arrangement with mr a. brown, agent of the steam-boat company, a 4-oared boat was waiting to take us to scarba and the corryvreckan. we were pulled across to the island of lunga, and rowed along its length, till we came to the first channel opening from the main sea, which the sailors called the little gulf. here the sea was rushing inwards in a manner of which i had no conception. streams were running with raving speed, sometimes in opposite directions side by side, with high broken-headed billows. where the streams touched were sometimes great whirls (one not many yards from our boat) that looked as if they would suck anything down. sometimes among all this were great smooth parts of the sea, still in a whirling trouble, which were surrounded by the mad currents. we seemed entirely powerless among all these." in the beginning of this year (1862) the duke of manchester, in writing to the rev. w. airy, had said, "i wish your brother, the astronomer royal, could be induced to have investigations made as to whether the aspects of the planets have any effect on the weather." this enquiry produced the following reply: a subject like that of the occult influences of the planets (using the word occult in no bad sense but simply as meaning not _thoroughly_ traced) can be approached in two ways--either by the ã  priori probability of the existence of such influences, or by the ã  posteriori evidence of their effects. if the two can be combined, the subject may be considered as claiming the dignity of a science. even if the effects alone are certain, it may be considered that we have a science of inferior degree, wanting however that definiteness of law and that general plausibility which can only be given when true causes, in accordance with antecedent experience in other cases, can be suggested. now in regard to the ã  priori probability of the existence of planetary influences, i am far from saying that such a thing is impossible. the discoveries of modern philosophy have all tended to shew that there may be many things about us, unknown even to the scientific world, but which well-followed accidents reveal with the most positive certainty. it is known that every beam of light is accompanied by a beam of chemical agency, totally undiscoverable to the senses of light or warmth, but admitting of separation from the luminous and warm rays; and producing photogenic effects. we know that there are disturbances of magnetism going on about us, affecting whole continents at a time, unknown to men in general, but traceable with facility and certainty, and which doubtless affect even our brains and nerves (which are indisputably subject to the influence of magnetism). now in the face of these things i will not undertake to say that there is any impossibility, or even any want of plausibility in the supposition that bodies external to the earth may affect us. it may well be cited in its favour that it is certain that the sun affects our magnetism (it is doubtful whether it does so _im_mediately, or mediately by giving different degrees of warmth to different parts of the earth), and it is believed on inferior evidence that the moon also affects it. it may therefore seem not impossible or unplausible that other celestial bodies may affect perhaps others of the powers of nature about us. but there i must stop. the denial of the impossibility is no assertion of the truth or probability, and i absolutely decline to take either side--either that the influences are real, or that the influences are unreal--till i see evidence of their effects. such evidence it is extremely difficult to extract from ordinary facts of observation. i have alluded to the sun's daily disturbance of the magnet as one of the most certain of influences, yet if you were to observe the magnet for a single day or perhaps for several days, you might see no evidence of that influence, so completely is it involved with other disturbances whose causes and laws are totally unknown. i believe that, in addition to the effects ascribable to newtonian gravitation (as general motion of the earth, precession of the equinoxes, and tides), this magnetic disturbance is the only one yet established as depending on an external body. men in general, however, do not think so. it appears to be a law of the human mind, to love to trace an effect to a cause, and to be ready to assent to any specious cause. thus all practical men of the lower classes, even those whose pecuniary interests are concerned in it, believe firmly in the influence of the moon upon the winds and the weather. i believe that every careful examiner of recorded facts (among whom i place myself as regards the winds) has come to the conclusion that the influence of the moon is not discoverable. i point out these two things (magnetic disturbances and weather) as tending to shew that notoriety or the assumed consent of practical men, are of no value. the unnotorious matter may be quite certain, the notorious matter may have no foundation. everything must stand on its own evidence, as completely digested and examined. of such evidence the planetary influence has not a particle. my intended short note has, in the course of writing, grown up into a discourse of very unreasonable length; and it is possible that a large portion of it has only increased obscurity. at any rate i can add nothing, i believe, which can help to explain more fully my views on this matter. * * * * * in this year (1862, june 9th) airy received the honorary degree of ll.d. in the university of cambridge. he was nominated by the duke of devonshire, as appears from the following letter: lismore castle, ireland, _april 19th, 1862_. my dear sir, it is proposed according to usage to confer a considerable number of honorary degrees on the occasion of my first visit to cambridge as chancellor of the university. i hope that you will allow me to include your name in that portion of the list which i have been invited to draw up. the ceremony is fixed for the 10th of june. i am, my dear sir, yours very truly, devonshire. _the astronomer royal_. * * * * * airy's reply was as follows: royal observatory, greenwich, london, s.e. _1862, april 21_. my lord duke, i am exceedingly gratified by your communication this day received, conveying a proposal which i doubt not is suggested by your grace's recollection of transactions now many years past. i have always been desirous of maintaining my connection with my university, and have in various ways interested myself practically in its concerns. it would give me great pleasure to have the connection strengthened in the flattering way which you propose. i had conceived that alumni of the university were not admissible to honorary degrees; but upon this point the information possessed by your grace, as chancellor of the university, cannot be disputed. i am, my lord duke, your grace's very faithful servant, g.b. airy. _his grace the duke of devonshire_. * * * * * there were in all 19 honorary degrees of doctor of laws conferred on the 9th of june, including men of such eminence as armstrong, faraday, and fairbairn. 1863 in this year there were several schemes for a railway through the lower part of greenwich park, the most important being the scheme of the london, chatham and dover railway company. in reference to this scheme the report to the visitors states "i may say briefly that i believe that it would be possible to render such a railway innocuous to the observatory; it would however be under restrictions which might be felt annoying to the authorities of the railway, but whose relaxation would almost ensure ruin to the observatory."--"the meridional observations of mars in the autumn of 1862 have been compared with those made at the observatory of williamstown, near melbourne, australia, and they give for mean solar parallax the value 8.932", exceeding the received value by about 1/24th part. (a value nearly identical with this 8.93" has also been found by comparing the pulkowa and cape of good hope observations.)"--"the results of the new dip-instrument in 1861 and 1862 appear to give a firm foundation for speculations on the state and change of the dip. as a general result, i may state as probable that the value of dip in the middle of 1843 was about 69â°1', and in the middle of 1862 about 68â°11'. the decrease of dip appears to be more rapid in the second half of this interval than in the first; the dip at beginning of 1853 being about 68â°44'."--with reference to the re-determination of the longitude of valencia, it is stated that "the concluded longitude agrees almost exactly with that determined by the transmission of chronometers in 1844; and entitles us to believe that the longitudes of kingstown and liverpool, steps in the chronometer conveyance, were determined with equal accuracy."--"the computations, for inferring the direction and amount of movement of the solar system in space from the observed proper motions of 1167 stars, have been completed. the result is, that the sun is moving towards a point, r.a. 264â°, n.p.d. 65â° (not very different from sir w. herschel's, but depending much in n.p.d. on the accuracy of bradley's quadrant observations), and that its annual motion subtends, at the distance of a star of the first magnitude, the angle 0.4". but the comparison, of the sum of squares of apparent proper motions uncorrected, with the sum of squares of apparent proper motions corrected for motion of sun, shews so small an advance in the explanation of the star's apparent movements as to throw great doubt on the certainty of results; the sum of squares being diminished by only 1/25th part."--"i had been writing strongly to maclear on the delays in publishing both the geodetic work and the star catalogue at the cape of good hope: he resolves to go on with these works. in december i am still very urgent about the geodesy." of private history: there was the usual short visit to playford at the beginning and end of the year.--"from june 27th to august 10th i was travelling in the north and west of scotland with my wife, my youngest son osmund, and my daughter annot." * * * * * in this year the offer of knighthood (for the third time) was made to airy through the rt hon. sir george c. lewis, bart. the offer was accepted on feb. 12th, 1863, but on the same day a second letter was written as follows: _1863, feb. 12_. dear sir, i am extremely ignorant of all matters connected with court ceremonial, and in reference to the proposed knighthood would ask you:-1. i trust that there is no expense of fees. to persons like myself of small fortune an honour may sometimes be somewhat dear. 2. my highest social rank is that given by my academical degree of d.c.l. which i hold in the universities of oxford and cambridge. in regard to costume, would it be proper that i should appear in the scarlet gown of that degree? or in the ordinary court dress? i am, dear sir, yours very faithfully, g.b. airy. _the right honourable sir george c. lewis, bart., &c. &c. &c._ to this letter sir g.c. lewis replied that the fees would amount to about _â£30_, an intimation which produced the following letter: royal observatory, greenwich, s.e. _1863, feb. 19th_. dear sir, i have to acknowledge your letter of yesterday: and i advert to that part of it in which it is stated that the fees on knighthood amount to about _â£30_. twenty-seven years ago the same rank was offered to me by lord john russell and mr spring rice (then ministers of the crown), with the express notice that no fees would be payable. i suppose that the usage (whatever it be) on which that notice was founded still subsists. to a person whose annual income little more than suffices to meet the annual expenses of a very moderate establishment, an unsought honour may be an incumbrance. it appears, at any rate, opposed to the spirit of such an honour, that it should be loaded with court expenses in its very creation. i hope that the principle stated in 1835 may serve as precedent on this occasion. i am, dear sir, your very faithful servant, g.b. airy. _the right honourable sir g. c. lewis, bart., &c. &c. &c._ no intimation however was received that the fees would be remitted on the present occasion, and after consideration the proposed knighthood was declined in the following letter: royal observatory, greenwich, s.e. _1863, april 15_. dear sir, i have frequently reflected on the proposal made by you of the honour of knighthood to myself. i am very grateful to you for the favourable opinion which you entertain in regard to my supposed claims to notice, and for the kindness with which you proposed publicly to express it. but on consideration i am strongly impressed with the feeling that the conditions attached by established regulation to the conferring of such an honour would be unacceptable to me, and that the honour itself would in reality, under the circumstances of my family-establishment and in my social position, be an incumbrance to me. and finally i have thought it best most respectfully, and with a full sense of the kindness of yourself and of the queen's government towards me, to ask that the proposal might be deferred. there is another direction in which a step might be made, affecting my personal position in a smaller degree, but not tending to incommode me, which i would ask leave to submit to your consideration. it is, the definition of the rank of the astronomer royal. the singular character of the office removes it from ordinary rules of rank, and sometimes may produce a disagreeable contest of opinions. the only offices of similar character corresponding in other conditions to that of the british astronomer royal are those of the imperial astronomers at pulkowa (st petersburg) and paris. in russia, where every rank is clearly defined by that of military grade, the imperial astronomer has the rank of major-general. in france, the definition is less precise, but the present imperial astronomer has been created (as an attachment of rank to the office) a senator of the empire. i am, dear sir, your very faithful servant, g.b. airy. _the rt hon. sir george c. lewis, bart., &c. &c. &c._ sir g. c. lewis died before receiving this letter, and the letter was afterwards forwarded to lord palmerston. some correspondence followed between lord palmerston and airy on the subject of attaching a definite rank to the office of astronomer royal, as proposed in the above letter. but the home office (for various reasons set forth) stated that the suggestion could not be complied with, and the whole subject dropped. 1864 the following remarks are extracted from the report of the astronomer royal to the board of visitors.--"in a very heavy squall which occurred in the gale of december 2 of last year, the stay of the lofty iron pillar outside of the park rails, which carried our telegraph wires, gave way, and the pillar and the whole system of wires fell."--"an important alteration has been made in the magnetic observatory. for several years past, various plans have been under consideration for preventing large changes of temperature in the room which contains the magnetic instruments. at length i determined to excavate a subterraneous room or cellar under the original room. the work was begun in the last week in january, and in all important points it is now finished."--"in the late spring, some alarm was occasioned by the discovery that the parliamentary standard of the pound weight had become coated with an extraneous substance produced by the decomposition of the lining of the case in which it was preserved. it was decided immediately to compare it with the three parliamentary copies, of which that at the observatory is one. the national standard was found to be entirely uninjured."--"on november 16 of last year, the transit instrument narrowly escaped serious injury from an accident. the plate chain which carries the large western counterpoise broke. the counterpoise fell upon the pier, destroying the massive gun-metal wheels of the lifting machinery, but was prevented from falling further by the iron stay of the gas-burner flue."--"the prismatic spectrum-apparatus had been completed in 1863. achromatic object-glasses are placed on both sides of the prism, so that each pencil of light through the prism consists of parallel rays; and breadth is given to the spectrum by a cylindrical lens. the spectral lines are seen straighter than before, and generally it is believed that their definition is improved."--"for observation of the small planets, a convention has been made with m. le verrier. from new moon to full moon, all the small planets visible to 13h are observed at the royal observatory of greenwich. from full moon to new moon, all are observed at the imperial observatory of paris. the relief gained in this way is very considerable."--"in determining the variations in the power of the horizontal-force and vertical-force magnets depending on temperature, it was found by experiment that this depended materially on whether the magnet was heated by air or by water, and 'the result of these experiments (with air) is to give a coefficient for temperature correction four or five times as great as that given by the water-heatings,'"--"with regard to the discordances of the results of observations of dip-needles, experiments had been made with needles whose breadth was in the plane passing through the axis of rotation, and it appeared that the means of extreme discordances were, for an ordinary needle 11' 45", and for a flat needle 3' 27"," and the report continues thus: "after this i need not say that i consider it certain that the small probable errors which have been attributed to ordinary needles are a pure delusion."--the report states that in the various operations connected with the trials and repairs of chronometers, and the system of time-signals transmitted to various time-balls and clocks, about one-fourth of the strength of the observatory is employed, and it continues thus: "viewing the close dependence of nautical astronomy upon accurate knowledge of time, there is perhaps no department of the observatory which answers more completely to the original utilitarian intentions of the founder of the royal observatory."--"with regard to the proposal of time-signals at the start point, it appears that communications referring to this proposal had passed between the board of admiralty and the board of trade, of which the conclusion was, that the board of trade possessed no funds applicable to the defraying of the expenses attending the execution of the scheme. and the admiralty did not at present contemplate the establishment of these time-signals under their own authority."--amongst other papers in this year, airy's paper entitled "first analysis of 177 magnetic storms," &c., was read before the royal society. of private history: "there was the usual visit to playford in the beginning of the year.--from june 8th to 23rd i made an excursion with my son hubert to the isle of man, and the lake district.--from sept. 7th to 14th i was on a trip to cornwall with my two eldest sons, chiefly in the mining district.--in august of this year my eldest (surviving) daughter, hilda, was married to mr e.j. routh, fellow of st peter's college, cambridge, at greenwich parish church. they afterwards resided at cambridge." 1865 "our telegraphic communications of every kind were again destroyed by a snow-storm and gale of wind which occurred on jan. 28th, and which broke down nearly all the posts between the royal observatory and the greenwich railway station.--the report to the visitors states that 'the only change of buildings which i contemplate as at present required is the erection of a fire-proof chronometer room. the pecuniary value of chronometers stored in the observatory is sometimes perhaps as much as _â£8000_.'--the south eastern and london chatham and dover scheme for a railway through the park was again brought forward. there was a meeting of sir j. hanmer's committee at the observatory on may 26th. mr stone was sent hastily to dublin to make observations on earth-disturbance by railways there. i had been before the committee on may 25th. on sept. 1st i approved of an amended plan. in reference to this matter the report states that 'it is proper to remark that the shake of the altazimuth felt in the earthquake of 1863, oct. 5th, when no such shake was felt with instruments nearer to the ground (an experience which, as i have heard on private authority, is supported by observation of artificial tremors), gives reason to fear that, at distances from a railway which would sufficiently defend the lower instruments, the loftier instruments (as the altazimuth and the equatoreals) would be sensibly affected.'--some of the magnets had been suspended by steel wires, instead of silk, of no greater strength than was necessary for safety, and the report states that 'under the pressure of business, the determination of various constants of adjustment was deferred to the end of the year. the immediate results of observation, however, began to excite suspicion; and after a time it was found that, in spite of the length of the suspending wire (about 8 feet) the torsion-coefficient was not much less than 1/6. the wires were promptly dismounted, and silk skeins substituted for them. with these, the torsion-coefficient is about 1/210.'--the dip-instrument, which had given great trouble by the irregularities of the dip-results, had been compared with two dip-instruments from kew observatory, which gave very good and accordant results. 'it happened that mr simms, by whom our instruments now in use were prepared, and who had personally witnessed our former difficulties, was present during some of these experiments. our own instrument being placed in his hands (nov. 10th to 19th) for another purpose, he spontaneously re-polished the apparently faultless agate-bearings. to my great astonishment, the inconsistencies of every kind have nearly or entirely vanished. on raising and lowering the needles, they return to the same readings, and the dips with the same needle appear generally consistent.' some practical details of the polishing process by which this result had been secured are then given.--after numerous delays, the apparatus for the self-registration of spontaneous earth currents was brought into a working state in the month of march. a description of the arrangement adopted is given in the report.--'all chronometers on trial are rated every day, by comparison with one of the clocks sympathetic with the motor clock. every chronometer, whether on trial or returned from a chronometer-maker as repaired, is tried at least once in the heat of the chronometer-oven, the temperature being usually limited to 90â° fahrenheit; and, guided by the results of very long experience, we have established it as a rule, that every trial in heat be continued through three weeks.'--'the only employment extraneous to the observatory which has occupied any of my time within the last year is the giving three lectures on the magnetism of iron ships (at the request of the lords of the committee of council on education) in the theatre of the south kensington museum. the preparations, however, for these lectures, to be given in a room ill-adapted to them, occupied a great deal of my own time, and of the time of an assistant of the observatory.'--'referring to a matter in which the interests of astronomy are deeply concerned, i think it right to report to the visitors my late representation to the government, to the effect that, in reference to possible observation of the transit of venus in 1882, it will be necessary in no long time to examine the coasts of the great southern continent.'" of private history: "there were the usual visits to playford at the beginning and end of the year.--from june 18th to 26th i was on a trip in wales with my sons hubert and osmund.--from sept. 6th to oct. 2nd i was staying with most of my family at portinscale near keswick: we returned by barnard castle, rokeby, &c." chapter viii. at greenwich observatory--1866 to 1876. 1866 in this year the cube of the transit circle was pierced, to permit reciprocal observations of the collimators without raising the instrument. this involved the construction of improved collimators, which formed the subject of a special address to the members of the board of visitors on oct. 21st 1865.--from the report to the visitors it appears that "on may 23rd 1865, a thunderstorm of great violence passed very close to the observatory. after one flash of lightning, i was convinced that the principal building was struck. several galvanometers in the magnetic basement were destroyed. lately it has been remarked that one of the old chimneys of the principal building had been dislocated and slightly twisted, at a place where it was surrounded by an iron stay-band led from the telegraph pole which was planted upon the leads of the octagon room."--"on consideration of the serious interruptions to which we have several times been exposed from the destruction of our open-air park-wires (through snow-storms and gales), i have made an arrangement for leading the whole of our wires in underground pipes as far as the greenwich railway station."--"the committee of the house of commons, to whom the greenwich and woolwich line of the south eastern railway was referred, finally assented to the adoption of a line which i indicated, passing between the buildings of the hospital schools and the public road to woolwich."--"the galvanic chronometer attached to the s. e. equatoreal often gave us a great deal of trouble. at last i determined, on the proposal of mr ellis, to attempt an extension of mr r. l. jones's regulating principle. it is well known that mr jones has with great success introduced the system of applying galvanic currents originating in the vibrations of a normal pendulum, not to drive the wheelwork of other clocks, but to regulate to exact agreement the rates of their pendulums which were, independently, nearly in agreement; each clock being driven by weight-power as before. the same principle is now applied to the chronometer.... the construction is perfectly successful; the chronometer remains in coincidence with the transit clock through any length of time, with a small constant error as is required by mechanical theory."--"the printed volume of observations for 1864 has two appendixes; one containing the calculations of the value of the moon's semi-diameter deduced from 295 occultations observed at cambridge and greenwich from 1832 to 1860, and shewing that the occultation semi-diameter is less than the telescopic semi-diameter by 2"; the other containing the reduction of the planetary observations made at the royal observatory in the years 1831-1835; filling up the gap, between the planetary reductions 1750-1830 made several years ago under my superintendence, and the reductions contained in the greenwich volumes 1836 to the present time: and conducted on the same general principles."--"some trouble had been found in regulating the temperature of the magnetic basement, but it was anticipated that in future there would be no difficulty in keeping down the annual variation within about 5â° and the diurnal variation within 3â°.--longitudes in america were determined in this year by way of valencia and newfoundland: finished by nov. 14th." of private history: in april he made a short visit to ventnor in the isle of wight.--from june 15th to july 23rd he was on an expedition in norway with his son osmund and his nephew gorell barnes.--there was probably a short stay at playford in the winter. in this and in the previous year (1865) the free-thinking investigations of colenso, the bishop of natal, had attracted much notice, and had procured him the virulent hostility of a numerous section. his income was withheld from him, and in consequence a subscription fund was raised for his support by his admirers. airy, who always took the liberal side in such questions, was a subscriber to the fund, and wrote the following letter to the bishop: royal observatory, greenwich, s.e., _1865, july 24_. my lord, with many thanks i have to acknowledge your kind recollection of me in sending as a presentation copy the work on joshua, judges, and especially on the divided authorship of genesis; a work whose investigations, founded in great measure on severe and extensive verbal criticism, will apparently bear comparison with your lordship's most remarkable examination of deuteronomy. i should however not do justice to my own appreciation if i did not remark that there are other points considered which have long been matters of interest to me. on several matters, some of them important, my present conclusions do not absolutely agree with your lordship's. but i am not the less grateful for the amount of erudition and thought carefully directed to definite points, and above all for the noble example of unwearied research and freedom in stating its consequences, in reference to subjects which scarcely ever occupy the attention of the clergy in our country. i am, my lord, yours very faithfully, g.b. airy. _the lord bishop of natal_. * * * * * here also is a letter on the same subject, written to professor selwyn, professor of divinity at cambridge:- royal observatory, greenwich, london, s.e., _1866, may 5_. my dear sir, the ms. concerning colenso duly arrived. i note your remarks on the merits of colenso. i do not write to tell you that i differ from you, but to tell you why i differ. i think that you do not make the proper distinction between a person who invents or introduces a tool, and the person who uses it. the most resolute antigravitationist that ever lived might yet acknowledge his debt to newton for the method of prime and ultimate ratios and the principles of fluxions by which newton sought to establish gravitation. so let it be with colenso. he has given me a power of tracing out truth to a certain extent which i never could have obtained without him. and for this i am very grateful. as to the further employment of this power, you know that he and i use it to totally different purposes. but not the less do i say that i owe to him a new intellectual power. i quite agree with you, that the sudden disruption of the old traditional view seems to have unhinged his mind, and to have sent him too far on the other side. i would not give a pin for his judgment. nevertheless, i wish he would go over the three remaining books of the tetrateuch. i know something of myers, but i should not have thought him likely to produce anything sound on such things as the hebrew scriptures. i never saw his "thoughts." i am, my dear sir, yours very truly, g.b. airy. _professor selwyn_. * * * * * the following letter has reference to airy's proposal to introduce certain physico-mathematical subjects into the senate-house examination for b.a. honors at cambridge. on various occasions he sharply criticized the papers set for the senate-house examination and the smith's prize examination, and greatly lamented the growing importance of pure mathematics and the comparative exclusion of physical questions in those examinations. his proposal as finally submitted in the letter that follows was somewhat modified (as regards the mode of introducing the subjects) from his original draft, in deference to the opinions of whewell, adams, routh, and other friends to whom he had submitted it. his proposal was favourably received by the mathematical board, and recommendations were made in the direction, though not to the extent, that he desired, and he subsequently submitted a memorandum on those recommendations: royal observatory, greenwich, _1866, may 11_. my dear sir, you will perceive, from perusal of the enclosed paper, that i have acted on the permission which you kindly gave me, to transmit to you my proposal for extension of the mathematical education of the university in the physical direction. it is an unavoidable consequence of the structure of the university that studies there will have a tendency to take an unpractical form depending much on the personal tastes of special examiners. i trust that, as a person whose long separation from the daily business of the university has enabled him to see in some measure the wants of the external scientific and practical world, i may be forgiven this attempt to bring to the notice of the university my ideas on the points towards which their attention might perhaps be advantageously turned. i am, my dear sir, very faithfully yours, g.b. airy. _the rev. dr cartmell, master of christ's college and vice-chancellor._ royal observatory, greenwich, _1866, may 11_. my dear mr vice-chancellor, about two years ago, by the kindness of the university, an opportunity was presented to me of orally stating what i conceived to be deficiencies in the educational course of the university as regards mathematical physics. since that time, the consideration of those deficiencies, which had long been present to me, has urged itself on my attention with greater force: and finally i have entertained the idea that i might without impropriety communicate to you my opinion, in a less fugitive form than on the occasion to which i have alluded: with the request that, if you should deem such a course appropriate, you would bring it before the board of mathematical studies, and perhaps ultimately make it known to the resident members of the senate. i will first give the list of subjects, which i should wish to see introduced, and to the prosecution of which the generally admirable course of the university is remarkably well adapted: and i will then, without entering into every detail, advert to the process by which i think it probable the introduction of these subjects could be effected. in the following list, the first head is purely algebraical, and the second nearly so: but they are closely related to observational science, and to the physical subjects which follow. some of the subjects which i exhibit on my list are partially, but in my opinion imperfectly, taught at present. i entirely omit from my list physical optics, geometrical astronomy, and gravitational astronomy of points: because, to the extent to which academical education ought to go, i believe that there is no teaching on these sciences comparable to that in the university of cambridge. (it is, of course, still possible that improvements may be made in the books commonly used.) it might, however, be a question, whether, as regards the time and manner of teaching them, some parts of these subjects might ultimately be associated with the other subjects included in my list. i. _list of subjects proposed for consideration_. (1) partial differential equations to the second order, with their arbitrary functions: selected principally with reference to the physical subjects. (2) the theory of probabilities as applied to the combination of observations. (3) mechanics (including hydraulic powers) in the state which verges upon practical application, and especially including that part in which the abstract ideas of _power_ and _duty_ occur. (4) attractions. this subject is recognized in the existing course of the university: but, so far as i can infer from examination-papers, it appears to be very lightly passed over. (5) the figure of the earth, and its consequences, precession, &c. i believe that the proposal is sanctioned, of adopting some part of this theory in the ordinary course; but perhaps hardly so far as is desirable. (6) the tides. (7) waves of water. (8) sound (beginning with newton's investigation); echoes; pipes and vibrating strings; acoustics; the mathematical part of music. (9) magnetism, terrestrial and experimental, and their connection. (i omit for the present mineralogy and mathematical electricity.) this list of subjects appears formidable: but they are in reality easy, and would be mastered in a short time by the higher wranglers. ii. _mode of introducing these subjects into the university_. after much consideration, and after learning the opinions of several persons whose judgment claims my deepest respect, i propose the gradual introduction of these subjects into the examination for honors at admission to the b.a. degree, as soon as the preparation of books and the readiness of examiners shall enable the university to take that step. i conceive that, by a judicious pruning of the somewhat luxuriant growth of pure algebra, analytical geometry, and mere problems, sufficient leisure may be gained for the studies of the undergraduates, and sufficient time for the questions of the examiners. i do not contemplate that the students could advance very far into the subjects; but i know the importance of beginning them; and, judging from the train of thoughts, of reading, and of conversation, among the bachelors with whom i associated many years ago, i believe that there is quite a sufficient number who will be anxious to go deep into the subjects if they have once entered into them. if six wranglers annually would take them up, my point would be gained. the part which these gentlemen might be expected, in a short time, to take in the government of the university, would enable them soon to act steadily upon the university course: the efficiency of the university instruction would be increased; and the external character of the university would be raised. the real difficulties, and they are not light ones, would probably be found in providing examiners and books. at present, both are wanting within the university. where there is a great and well-founded objection to intrusting examinations to persons foreign to the university, and where the books have to be created with labour and with absolute outlay of money (for their sale could never be remunerative), the progress must be slow. still progress would be certain, if the authorities of the university should think the matter deserving of their hearty encouragement. requesting that you and the members of the university will accept this proposal as an indication of my deep attachment to my university, i am, my dear mr vice-chancellor, your very faithful servant, g.b. airy. _the rev. dr cartmell, &c. &c. vice-chancellor of the university of cambridge_. 1867 "in this year it was arranged that my treasury accounts were to be transferred to the admiralty, making the simplification which i had so long desired.--from the report to the visitors it appears that a relic of the geodetic operations commenced in 1787 for connecting the observatories of greenwich and paris, in the shape of an observing cabin on the roof of the octagon room, was shifted and supported in such a manner that the pressure on the flat roof was entirely avoided.--with regard to the transit circle, the new collimators with telescopes of seven inches aperture had been mounted. when the transit telescope directed vertically is interposed, the interruptions in the central cube impair the sharpness of definition, still leaving it abundantly good for general use. it had been regarded as probable that the astronomical flexure of the telescope, after cutting away small portions of the central cube, would be found sensibly changed: and this proved to be the case. the difference of flexures of the two ends has been altered more than a second of arc.--referring to a new portable altazimuth which had lately been tested, the report states as follows: 'i may mention that a study of defects in the vertical circle of a small altazimuth formerly used by me, and an inspection of the operations in the instrument-maker's work-shop, have convinced me that the principal error to be feared in instruments of this class is ovality of the graduated limb; this cannot be eliminated by two microscopes, and such an instrument should never be fitted with two only. our instrument has four.'--'in osler's anemometer, a surface of 2 square feet is now exposed to the wind instead of one foot as formerly; and the plate is supported by weak vertical springs instead of rods running on rollers. its indications are much more delicate than formerly.'--'the meteors on nov. 14th were well observed. eight thousand and three hundred were registered. the variations of frequency at different times were very well noted. the points of divergence were carefully determined.'--referring to the gradual improvement in the steadiness of chronometers from 1851 to 1866, it appears that from 1851 to 1854 the 'trial number' (which is a combination of changes of weekly rate representing the fault of the chronometer) varied from 34.8s to 52.5s, while from 1862 to 1866 it varied from 21.2s to 25.8s.--the following statement will shew the usual steadiness of the great clock on the westminster palace: on 38 per cent. of days of observation, the clock's error was below 1s. on 38 per cent, the error was between 1s and 2s. on 21 per cent. it was between 2s and 3s. on 2 per cent. between 3s and 4s. on 1 per cent. between 4s and 5s.--the report contains an account of the determination of the longitude of cambridge u.s. by dr b. a. gould, by means of galvanic currents through the atlantic cable, in the spring of 1867: and advantage was taken of this opportunity for re-determining the longitude of feagh main near valencia in ireland. the longitude of feagh main, found by different methods is as follows: by chronometers in 1844, 41m 23.23s; by galvanic communication with knight's town in 1862, 41m 23.37s; by galvanic communication with foilhommerum in 1866, 41m 23.19s. the collected results for longitude of cambridge u.s. from different sources are: by moon-culminators (walker in 1851, and newcomb in 1862-3), 4h 44m 28.42s and 4h 44m 29.56s respectively; by eclipses (walker in 1851), 4h 44m 29.64s; by occultations of pleiades (peirce 1838-1842, and 1856-1861), 4h 44m 29.91s and 4h 44m 30.90s respectively; by chronometers (w. c. bond in 1851, and g. p. bond in 1855), 4h 44m 30.66s and 4h 44m 31.89s respectively; by atlantic cable 1866, 4h 44m 30.99s.--after noticing that many meteorological observatories had suddenly sprung up and had commenced printing their observations in detail, the report continues thus: 'whether the effect of this movement will be that millions of useless observations will be added to the millions that already exist, or whether something may be expected to result which will lead to a meteorological theory, i cannot hazard a conjecture. this only i believe, that it will be useless, at present, to attempt a process of mechanical theory; and that all that can be done must be, to connect phenomena by laws of induction. but the induction must be carried out by numerous and troublesome trials in different directions, the greater part of which would probably be failures.'--there was this year an annular eclipse; i made large preparations at the limits of the annularity; failed entirely from very bad weather."--in this year airy contributed a paper to the institution of civil engineers 'on the use of the suspension bridge with stiffened roadway for railway and other bridges of great span,' for which a telford medal was awarded to him by the council of the institution. and he communicated several papers to the royal society and the royal astronomical society. of private history: there was the usual visit to playford in january.--in april there was a short run to alnwick and the neighbourhood, in company with mr and mrs routh.--from june 27th to july 4th he was in wales with his two eldest sons, visiting uriconium, &c. on his return.--from august 8th to sept. 7th he spent a holiday in scotland and the lake district of cumberland with his daughter christabel, visiting the langtons at barrow house, near keswick, and isaac fletcher at tarn bank. in june of this year (1867) airy was elected an honorary fellow of his old college of trinity in company with connop thirlwall, the bishop of st david's. they were the first honorary fellows elected by the college. the announcement was made in a letter from the master of trinity (w.h. thompson), and airy's reply was as follows: royal observatory, greenwich, london, s.e. _1867, june 12th_. my dear master, i am very much gratified by your kind note received this morning, conveying to me the notice that the master and sixteen senior fellows had elected me, under their new powers, as honorary fellow of the college. it has always been my wish to maintain a friendly connection with my college, and i am delighted to receive this response from the college. the peculiar form in which the reference to the statute enables them to put it renders it doubly pleasing. as the statute is new, i should be obliged by a copy of it. and, at any convenient time, i should be glad to know the name of the person with whom i am so honorably associated. i am, my dear master, very faithfully yours, g.b. airy. * * * * * consequent on airy's proposals in 1866 for the introduction of new physical subjects into the senate-house examination and his desire that the large number of questions set in pure mathematics, or as he termed it "useless algebra," should be curtailed, there was a smart and interesting correspondence between him and prof. cayley, who was the great exponent and advocate of pure mathematics at cambridge. both of them were men of the highest mathematical powers, but diametrically opposed in their views of the use of mathematics. airy regarded mathematics as simply a useful machine for the solution of practical problems and arriving at practical results. he had a great respect for pure mathematics and all the processes of algebra, so far as they aided him to solve his problems and to arrive at useful results; but he had a positive aversion to mathematical investigations, however skilful and elaborate, for which no immediate practical value could be claimed. cayley on the contrary regarded mathematics as a useful exercise for the mind, apart from any immediate practical object, and he considered that the general command of mathematics gained by handling abstruse mathematical investigations (though barren in themselves) would be valuable for whatever purpose mathematics might be required: he also thought it likely that his researches and advances in the field of pure mathematics might facilitate the solution of physical problems and tend to the progress of the practical sciences. their different views on this subject will be seen from the letters that follow: royal observatory, greenwich, london, s.e. _1867, nov. 8_. my dear sir, i think it best to put in writing the purport of what i have said, or have intended to say, in reference to the mathematical studies in the university. first, i will remark on the study of partial differential equations. i do not know that one branch of pure mathematics can be considered higher than another, except in the utility of the power which it gives. measured thus, the partial differential equations are very useful and therefore stand very high, as far as the second order. they apply, to that point, in the most important way, to the great problems of nature concerning _time_, and _infinite division of matter_, and _space_: and are worthy of the most careful study. beyond that order they apply to nothing. it was for the purpose of limiting the study to the second order, and at the same time working it carefully, philosophically, and practically, up to that point, that i drew up my little work. on the general question of mathematical studies, i will first give my leading ideas on what i may call the moral part. i think that a heavy responsibility rests on the persons who influence most strongly the course of education in the university, to direct that course in the way in which it will be most useful to the students--in the two ways, of disciplining their powers and habits, and of giving them scientific knowledge of the highest and most accurate order (applying to the phenomena of nature) such as will be useful to them through life. i do not think that the mere personal taste of a teacher is sufficient justification for a special course, unless it has been adopted under a consideration of that responsibility. now i can say for myself that i have, for some years, inspected the examination papers, and have considered the bearing of the course which they imply upon the education of the student, and am firmly convinced that as regards men below the very few first--say below the ten first--there is a prodigious loss of time without any permanent good whatever. for the great majority of men, such subjects as abstract analytical geometry perish at once. with men like adams and stokes they remain, and are advantageous; but probably there is not a single man (beside them) of their respective years who remembers a bit, or who if he remembers them has the leisure and other opportunities of applying them. i believe on the other hand that a careful selection of physical subjects would enable the university to communicate to its students a vast amount of information; of accurate kind and requiring the most logical treatment; but so bearing upon the natural phenomena which are constantly before us that it would be felt by every student to possess a real value, that (from that circumstance) it would dwell in his mind, and that it would enable him to correct a great amount of flimsy education in the country, and, so far, to raise the national character. the consideration of the education of the reasoning habits suggests ideas far from favourable to the existing course. i am old enough to remember the time of mere geometrical processes, and i do not hesitate to say that for the cultivation of accurate mental discipline they were far superior to the operations in vogue at the present day. there is no subject in the world more favourable to logical habit than the differential calculus in all its branches _if logically worked in its elements_: and i think that its applications to various physical subjects, compelling from time to time an attention to the elementary grounds of the calculus, would be far more advantageous to that logical habit than the simple applications to pure equations and pure algebraical geometry now occupying so much attention. i am, my dear sir, yours very truly, g.b. airy. _professor cayley_. * * * * * dear sir, i have been intending to answer your letter of the 8th november. so far as it is (if at all) personal to myself, i would remark that the statutory duty of the sadlerian professor is that he shall explain and teach the principles of pure mathematics and apply himself to the advancement of the science. as to partial differential equations, they are "high" as being an inverse problem, and perhaps the most difficult inverse problem that has been dealt with. in regard to the limitation of them to the second order, whatever other reasons exist for it, there is also the reason that the theory to this order is as yet so incomplete that there is no inducement to go beyond it; there could hardly be a more valuable step than anything which would give a notion of the form of the general integral of a partial differential equation of the second order. i cannot but differ from you _in toto_ as to the educational value of analytical geometry, or i would rather say of modern geometry generally. it appears to me that in the physical sciences depending on partial differential equations, there is scarcely anything that a student can do for himself:--he finds the integral of the ordinary equation for sound--if he wishes to go a step further and integrate the non-linear equation (dy/dx)â²(dâ²y/dtâ²) = aâ²(dâ²y/dxâ²) he is simply unable to do so; and so in other cases there is nothing that he can add to what he finds in his books. whereas geometry (of course to an intelligent student) is a real inductive and deductive science of inexhaustible extent, in which he can experiment for himself--the very tracing of a curve from its equation (and still more the consideration of the cases belonging to different values of the parameters) is the construction of a theory to bind together the facts--and the selection of a curve or surface proper for the verification of any general theorem is the selection of an experiment in proof or disproof of a theory. i do not quite understand your reference to stokes and adams, as types of the men who alone retain their abstract analytical geometry. if a man when he takes his degree drops mathematics, he drops geometry--but if not i think for the above reasons that he is more likely to go on with it than with almost any other subject--and any mathematical journal will shew that a very great amount of attention is in fact given to geometry. and the subject is in a very high degree a progressive one; quite as much as to physics, one may apply to it the lines, yet i doubt not thro' the ages one increasing purpose runs, and the thoughts of men are widened with the progress of the suns. i remain, dear sir, yours very sincerely, a. cayley. cambridge, _6 dec., 1867_. * * * * * royal observatory, greenwich, london, s.e. _1867, december 9_. my dear sir, i have received with much pleasure your letter of december 6. in this university discussion, i have acted only in public, and have not made private communication to any person whatever till required to do so by private letter addressed to me. your few words in queens' hall seemed to expect a little reply. now as to the modern geometry. with your praises of this science--as to the room for extension in induction and deduction, &c.; and with your facts--as to the amount of space which it occupies in mathematical journals; i entirely agree. and if men, after leaving cambridge, were designed to shut themselves up in a cavern, they could have nothing better for their subjective amusement. they might have other things as good; enormous complication and probably beautiful investigation might be found in varying the game of billiards with novel islands on a newly shaped billiard table. but the persons who devote themselves to these subjects do thereby separate themselves from the world. they make no step towards natural science or utilitarian science, the two subjects which the world specially desires. the world could go on as well without these separatists. now if these persons lived only for themselves, no other person would have any title to question or remark on their devotion to this barren subject. but a cambridge examiner is not in that position. the university is a national body, for education of young men: and the power of a cambridge examiner is omnipotent in directing the education of the young men; and his responsibility to the cause of education is very distinct and very strong. and the question for him to consider is--in the sense in which mathematical education is desired by the best authorities in the nation, is the course taken by this national institution satisfactory to the nation? i express my belief that it is _not_ satisfactory. i believe that many of the best men of the nation consider that a great deal of time is lost on subjects which they esteem as puerile, and that much of that time might be employed on noble and useful science. you may remember that the commissions which have visited cambridge originated in a memorial addressed to the government by men of respected scientific character: sabine was one, and i may take him as the representative. he is a man of extensive knowledge of the application of mathematics as it has been employed for many years in the science of the world; but he has no profundity of science. he, as i believe, desired to find persons who could enter accurately into mathematical science, and naturally looked to the great mathematical university; but he must have been much disappointed. so much time is swallowed up by the forced study of the pure mathematics that it is not easy to find anybody who can really enter on these subjects in which men of science want assistance. and so sabine thought that the government ought to interfere, probably without any clear idea of what they could do. i am, my dear sir, yours very truly, g.b. airy. _professor cayley_. * * * * * dear sir, i have to thank you for your last letter. i do not think everything should be subordinated to the educational element: my idea of a university is that of a place for the cultivation of all science. therefore among other sciences pure mathematics; including whatever is interesting as part of this science. i am bound therefore to admit that your proposed extension of the problem of billiards, _if it_ were found susceptible of interesting mathematical developments, would be a fit subject of study. but in this case i do not think the problem could fairly be objected to as puerile--a more legitimate objection would i conceive be its extreme speciality. but this is not an objection that can be brought against modern geometry as a whole: in regard to any particular parts of it which may appear open to such an objection, the question is whether they are or are not, for their own sakes, or their bearing upon other parts of the science to which they belong, worthy of being entered upon and pursued. but admitting (as i do not) that pure mathematics are only to be studied with a view to natural and physical science, the question still arises how are they best to be studied in that view. i assume and admit that as to a large part of modern geometry and of the theory of numbers, there is no present probability that these will find any physical applications. but among the remaining parts of pure mathematics we have the theory of elliptic functions and of the jacobian and abelian functions, and the theory of differential equations, including of course partial differential equations. now taking for instance the problem of three bodies--unless this is to be gone on with by the mere improvement in detail of the present approximate methods--it is at least conceivable that the future treatment of it will be in the direction of the problem of two fixed centres, by means of elliptic functions, &c.; and that the discovery will be made not by searching for it directly with the mathematical resources now at our command, but by "prospecting" for it in the field of these functions. even improvements in the existing methods are more likely to arise from a study of differential equations in general than from a special one of the equations of the particular problem: the materials for such improvements which exist in the writings of hamilton, jacobi, bertrand, and bour, have certainly so arisen. and the like remarks would apply to the physical problems which depend on partial differential equations. i think that the course of mathematical study at the university is likely to be a better one if regulated with a view to the cultivation of science, as if for its own sake, rather than directly upon considerations of what is educationally best (i mean that the best educational course will be so obtained), and that we have thus a justification for a thorough study of pure mathematics. in my own limited experience of examinations, the fault which i find with the men is a want of analytical power, and that whatever else may have been in defect pure mathematics has certainly not been in excess. i remain, dear sir, yours sincerely, a. cayley. cambridge, _10th dec., 1867_. * * * * * _1867, december 17_. my dear sir, since receiving your letter of 9th i positively have not had time to express the single remark which i proposed to make on it. you state your idea that the educational element ought not to be the predominating element in the university. "i do not think that every thing should be subordinated to the educational element." i cannot conceal my surprise at this sentiment. assuredly the founders of the colleges intended them for education (so far as they apply to persons in statu pupillari), the statutes of the university and the colleges are framed for education, and fathers send their sons to the university for education. if i had not had your words before me, i should have said that it is impossible to doubt this. it is much to be desired that professors and others who exercise no control by force should take every method, not only of promoting science in themselves, but also of placing the promoted science before students: and it is much to be desired that students who have passed the compulsory curriculum should be encouraged to proceed into the novelties which will be most agreeable to them. but this is a totally different thing from using the compulsory force of examination to drive students in paths traced only by the taste of the examiner. for them, i conceive the obligation to the nation and the duty to follow the national sense on education (as far as it can be gathered from its best representatives) to be undoubted; and to be, in the intensity of the obligation and duty, most serious. i am, my dear sir, yours very truly, g.b. airy. _professor cayley_. * * * * * 1868 "in the south-east dome, the alteration proposed last year for rendering the building fire-proof had been completely carried out. the middle room, which was to be appropriated to chronometers, was being fitted up accordingly.--from the report it appears that 'our subterranean telegraph wires were all broken by one blow, from an accident in the metropolitan drainage works on groom's hill, but were speedily repaired.'--in my office as chairman of successive commissions on standards, i had collected a number of standards, some of great historical value (as ramsden's and roy's standards of length, kater's scale-beam for weighing great weights, and others), &c. these have been transferred to the newly-created standards department of the board of trade."--in the report is given a detailed account of the system of preserving and arranging the manuscripts and correspondence of the observatory, which was always regarded by airy as a matter of the first importance.--from a careful discussion of the results of observation mr stone had concluded that the refractions ought to be diminished. 'relying on this, we have now computed our mean refractions by diminishing those of bessel's fundamenta in the proportion of 1 to 0.99797.'--the magnetometer-indications for the period 1858-1863 had been reduced and discussed, with remarkable results. it is inferred that magnetic disturbances, both solar and lunar, are produced mediately by the earth, and that the earth in periods of several years undergoes changes which fit it and unfit it for exercising a powerful mediate action.--the earth-current records had been reduced, and the magnetic effect which the currents would produce had been computed. the result was, that the agreement between the magnetic effects so computed and the magnetic disturbances really recorded by the magnetometers was such as to leave no doubt on the general validity of the explanation of the great storm-disturbances of the magnets as consequences of the galvanic currents through the earth.--referring to the difficulty experienced in making the meteorological observations practically available the report states thus: 'the want of meteorology, at the present time, is principally in suggestive theory.'--in this year airy communicated to the royal astronomical society a paper 'on the preparatory arrangements for the observation of the transits of venus 1874 and 1882': this subject was now well in hand.--the first report of the commissioners (of whom he was chairman) appointed to enquire into the condition of the exchequer standards was printed: this business took up much time.--he was in this year much engaged on the coinage commission. of private history: there was the usual winter visit to playford, and a short visit to cambridge in june.--from about aug. 1st to sept. 3rd he was travelling in switzerland with his youngest son and his two youngest daughters. in the course of this journey they visited zermatt. there had been much rain, the rivers were greatly flooded, and much mischief was done to the roads. during the journey from visp to zermatt, near st nicholas, in a steep part of the gorge, a large stone rolled from the cliffs and knocked their baggage horse over the lower precipice, a fall of several hundred feet. the packages were all burst, and many things were lost, but a good deal was recovered by men suspended by ropes. in this year also airy was busy with the subject of university examination, which in previous years had occupied so much of his attention, as will be seen from the following letters: royal observatory, greenwich, london, s.e. _1868, march 12_. my dear master, i have had the pleasure of corresponding with you on matters of university examination so frequently that i at once turn to you as the proper person to whom i may address any remarks on that important subject. circumstances have enabled me lately to obtain private information of a most accurate kind on the late mathematical tripos: and among other things, i have received a statement of every individual question answered or partly answered by five honour-men. i have collected the numbers of these in a small table which i enclose. i am struck with the _almost_ nugatory character of the five days' honour examination as applied to senior optimes, and i do not doubt that it is _totally_ nugatory as applied to junior optimes. it appears to me that, for all that depends on these days, the rank of the optimes is mere matter of chance. in the examinations of the civil service, the whole number of marks is published, and also the number of marks gained by each candidate. i have none of their papers at hand, but my impression is that the lowest candidates make about 1 in 3; and the fair candidates about 2 in 3, instead of 1 in 10 or 1 in 13 as our good senior optimes. i am, my dear master, very truly yours, g.b. airy. _the rev. dr cookson, master of st peters college, &c. &c._ the table referred to in the above letter is as follows: number of questions, and numbers of answers to questions as given by several wranglers and senior optimes, in the examination of mathematical tripos for honours, 1868, january 13, 14, 15, 16, 17. number of questions and riders in the printed papers. questions. riders. aggregate. in the 10 papers of the 5 days 123 101 224 number of questions and riders answered. questions. riders. aggregate. by a wrangler, between the 1st and 7th 69-1/2 25-1/2 95 1 in 2.36 by a wrangler, between the 12th and 22nd 48-1/2 12-1/2 61 1 in 3.68 by a wrangler, between the 22nd and 32nd 36 12-1/2 48-1/2 1 in 4.62 by a sen. opt. between the 1st and 10th 17-1/2 5 22-1/2 1 in 9.95 by a sen. opt. between the 10th and 20th 14-1/2 2 16-1/2 1 in 3.60 g.b. airy. _1868, march 12_. * * * * * st peter's college lodge, cambridge, _march 13th, 1868_. my dear sir, i am much obliged by your letter and enclosed paper. anything done in the last five days by a junior optime only shews (generally) that he has been employing some of his time _mischievously_, for he must have been working at subjects which he is quite unable to master or cramming them by heart on the chance of meeting with a stray question which he may answer. the chief part of the senior optimes are in something of the same situation. i think that the proposed addition of a day to the first part of the examination, in which "easy questions in physical subjects" may be set, is, on this account, a great improvement. our new scheme comes on for discussion on friday next, march 20, at 2 p.m. in the arts school. it is much opposed by private tutors, examiners and others, and may possibly be thrown out in the senate this year, though i hope that with a little patience it may be carried, in an unmutilated form, eventually. the enclosed report on the smith's prize examination will be discussed at the same time. i will consider what is best to be done on the subject to which your note refers, without delay. with many thanks, i am, very faithfully yours, h.w. cookson, _the astronomer royal._ * * * * * in this year certain members of the senate of the university of cambridge petitioned parliament against the abolition of religious declarations required of persons admitted to fellowships or proceeding to the degree of m.a. the document was sent to airy for his signature, and his reply was as follows: royal observatory, greenwich, london, s.e. _1868, march 18_. my dear sir, though i sympathize to a great extent with the prayer of the petition to parliament which you sent to me yesterday, and assent to most of the reasons, i do not attach my signature to it, for the following considerations: 1. i understand, from the introductory clause, and from the unqualified character of the phrase "any such measures" in the second clause, that the petition objects to granting the m.a. degree without religious declaration. i do not see any adequate necessity for this objection, and i cannot join in it. 2. it appears to me that the colleges were intended for two collateral objects:--instruction by part of the fellows, on a religious basis; and support of certain fellows for scientific purposes, without the same ostentatious connection with religion. i like this spirit well, and should be glad to maintain it. 3. i therefore think (as i have publicly stated before) that the master of the college ought to be in holy orders; and so ought those of the fellows who may be expected to be usually resident and to take continuous part in the instruction. but there are many who, upon taking a fellowship, at once lay aside all thoughts of this: and i think that such persons ought not to be trammelled with declarations. 4. my modification of existing regulations, if it once got into shape, would i dare say be but a small fraction of that proposed by the "measures in contemplation." still i do not like to join in unqualified resistance to interference in the affairs of the established colleges, with that generality of opposition to interference which the petition seems to intimate. i agree with articles 3, 4, and 5; and i am pleased with the graceful allusion in article 4 to the assistance which has been rendered by the colleges, and by none perhaps so honourably as trinity, to the parishes connected with it. and i could much wish that the spirit of 3 and 5 could be carried out, with some concession to my ideas in _my_ paragraph 3, above. i am, my dear sir, yours very truly, g.b. airy. _rev. dr lightfoot._ * * * * * 1869 from the report to the board of visitors it appears that application had been made for an extension of the grounds of the observatory to a distance of 100 feet south of the magnetic ground, and that a warrant for the annexation of this space was signed on 1868, dec. 8. the new depã´t for the printed productions of the observatory had been transferred to its position in the new ground, and the foundations for the great shed were completed.--"the courses of our wires for the registration of spontaneous terrestrial galvanic currents have been entirely changed. the lines to croydon and deptford are abandoned; and for these are substituted, a line from angerstein wharf to lady well station, and a line from north kent junction to morden college tunnel. at each of these points the communication with earth is made by a copper plate 2 feet square. the straight line connecting the extreme points of the first station intersects that connecting the two points of the second station, nearly at right angles, and at little distance from the observatory.--the question of dependence of the measurable amount of sidereal aberration upon the thickness of glass or other transparent material in the telescope (a question which involves, theoretically, one of the most delicate points in the undulatory theory of light) has lately been agitated on the continent with much earnestness. i have calculated the curvatures of the lenses of crown and flint glass (the flint being exterior) for correcting spherical and chromatic aberration in a telescope whose tube is filled with water, and have instructed mr simms to proceed with the preparation of an instrument carrying such a telescope. i have not finally decided whether to rely on zenith-distances of gamma draconis or on right-ascensions of polaris. in any form the experiment will probably be troublesome.--the transit of mercury on 1868, nov. 4th, was observed by six observers. the atmospheric conditions were favourable; and the singular appearances usually presented in a planetary transit were well seen.--mr stone has attached to the south-east equatoreal a thermo-multiplier, with the view of examining whether heat radiating from the principal stars can be made sensible in our instruments. the results hitherto obtained are encouraging, but they shew clearly that it is vain to attempt this enquiry except in the most superb weather; and there has not been a night deserving that epithet for some months past.--the preparations for observing the transits of venus were now begun in earnest. i had come to the conclusion, that after every reliance was placed on foreign and colonial observatories, it would be necessary for the british government to undertake the equipment of five or six temporary stations. on feb. 15th i sent a pamphlet on the subject to mr childers (first lord of admiralty), and in april i wrote to the secretary, asking authority for the purchase of instruments. on june 22nd authority is given to me for the instruments: the treasury assent to _â£10,500_. on august 9th i had purchased 3 equatoreals.--i have given a short course of lectures in the university of cambridge on the subject of magnetism, with the view of introducing that important physical science into the studies of the university. the want of books available to students, and the novelty of the subject, made the preparation more laborious than the duration of the lectures would seem to imply."--in this year there was much work on the standards commission, chiefly regarding the suggested abolition of troy weight, and several papers on the subject were prepared by airy.--he also wrote a long and careful description of the great equatoreal at greenwich. of private history: there was the usual visit to playford in the winter. mrs airy was now becoming feebler, and did not now leave greenwich: since april of this year her letters were written in pencil, and with difficulty, but she still made great efforts to keep up the accustomed correspondence.--in april airy went to cambridge to deliver his lectures on magnetism to the undergraduates: the following passage occurs in one of his letters at this time: "i have a mighty attendance (there were 147 names on my board yesterday), and, though the room is large with plenty of benches, i have been obliged to bring in some chairs. the men are exceedingly attentive, and when i look up i am quite struck to see the number of faces staring into mine. i go at 12, and find men at the room copying from my big papers: i lecture from 1 to 2, and stop till after 3, and through the last hour some men are talking to me and others are copying from the papers; and i usually leave some men still at work. the men applaud and shew their respect very gracefully. there are present some two or three persons who attended my former lectures, and they say that i lecture exactly as i did formerly. one of my attendants is a man that they say cannot, from years and infirmity and habit, be induced to go anywhere else: dr archdall, the master of emmanuel. i find that some of my old lecturing habits come again on me. i drink a great deal of cold water, and am very glad to go to bed early."--from june 10th-30th he was travelling in scotland, and staying at barrow house near keswick (the residence of mr langton), with his son hubert.--subsequently, from aug. 17th to 31st, he was again in the lake district, with his daughter christabel, and was joined there by his son hubert on the 24th. the first part of the time was spent at tarn bank, near carlisle, the residence of mr isaac fletcher, m.p. from thence he made several expeditions, especially to barrow in furness and seascale, where he witnessed with great interest the bessemer process of making steel. from barrow house he made continual excursions among the cumberland mountains, which he knew so well. 1870 "in this year mr stone, the first assistant, was appointed to the cape of good hope observatory, and resigned his post of first assistant. mr christie was appointed in his place.--from the report to the visitors it appears that 'a few months since we were annoyed by a failure in the illumination of the field of view of the transit circle. the reflector was cleaned, but in vain; at last it was discovered that one of the lenses (the convex lens) of the combination which forms the object-glass of a reversed telescope in the interior of the transit-axis, and through which all illuminating light must pass, had become so corroded as to be almost opaque.'--the south-east equatoreal has been partly occupied with the thermo-multiplier employed by mr stone for the measure of heat radiating from the principal stars. mr stone's results for the radiation from arcturus and alpha lyrae appear to be incontrovertible, and to give bases for distinct numerical estimation of the radiant heat of these stars.--in my last report i alluded to a proposed systematic reduction of the meteorological observations during the whole time of their efficient self-registration. having received from the admiralty the funds necessary for immediate operations, i have commenced with the photographic registers of the thermometers, dry-bulb and wet-bulb, from 1848 to 1868.--our chronometer-room contains at present 219 chronometers, including 37 chronometers which have been placed here by chronometer-makers as competing for the honorary reputation and the pecuniary advantages to be derived from success in the half-year's trial to which they are subjected. i take this opportunity of stating that i have uniformly advocated the policy of offering good prices for the chronometers of great excellence, and that i have given much attention to the decision on their merits; and i am convinced that this system has greatly contributed to the remarkably steady improvement in the performance of chronometers. in the trial which terminated in august 1869, the best chronometers (taking as usual the average of the first six) were superior in merit to those of any preceding year.--with the funds placed at my disposal for the transit of venus 1874 i purchased three 6-inch equatoreals, and have ordered two: i have also ordered altazimuths (with accurate vertical circles only), and clocks sufficient, as i expect, to equip five stations. for methods of observation, i rely generally on the simple eye-observation, possibly relieved of some of its uncertainty by the use of my colour-correcting eyepiece. but active discussion has taken place on the feasibility of using photographic and spectroscopic methods; and it will not be easy for some time to announce that the plan of observations is settled.--there can be no doubt, i imagine, that the first and necessary duty of the royal observatory is to maintain its place well as an observing establishment; and that this must be secured, at whatever sacrifice, if necessary, of other pursuits. still the question has not unfrequently presented itself to me, whether the duties to which i allude have not, by force of circumstances, become too exclusive; and whether the cause of science might not gain if, as in the imperial observatory of paris for instance, the higher branches of mathematical physics should not take their place by the side of observatory routine. i have often felt the desire practically to refresh my acquaintance with what were once favourite subjects: lunar theory and physical optics. but i do not at present clearly see how i can enter upon them with that degree of freedom of thought which is necessary for success in abstruse investigations." of private history: there was a longer visit than usual to playford, lasting till jan. 27th.--in april he made a short excursion (of less than a week) with his son hubert to monmouth, &c.--from june 14th to july 2nd he was staying at barrow house, near keswick, with his son hubert: during this time he was much troubled with a painful skin-irritation of his leg and back, which lasted in some degree for a long time afterwards.--from sept. 25th to oct. 6th he made an excursion with his daughter christabel to scarborough, whitby, &c., and again spent a few days at barrow house. 1871 "in april 1870 the assistants had applied for an increase of salary, a request which i had urged strongly upon the admiralty. on jan. 27 of this year the admiralty answered that, on account of mr childers's illness, the consideration must be deferred to next year! the assistants wrote bitterly to me: and with my sanction they wrote to the first lord. on jan. 31st i requested an interview with mr baxter (secretary of the admiralty), and saw him on feb. 3rd, when i obtained his consent to an addition of _â£530_. there was still a difficulty with the treasury, but on june 27th the liberal scale was allowed.--experiments made by mr stone shew clearly that a local elevation, like that of the royal observatory on the hill of greenwich park, has no tendency to diminish the effect of railway tremors.--the correction for level error in the transit circle having become inconveniently large, a sheet of very thin paper, 1/270 inch in thickness, was placed under the eastern y, which was raised from its bed for the purpose. the mean annual value of the level-error appears to be now sensibly zero.--as the siege and war operations in paris seriously interfered with the observations of small planets made at the paris observatory, observations of them were continued at greenwich throughout each entire lunation during the investment of the city.--the new water-telescope has been got into working order, and performs most satisfactorily. observations of gamma draconis have been made with it, when the star passed between 20h and 17h, with some observations for adjustment at a still more advanced time. as the astronomical latitude of the place of observation is not known, the bearing of these observations on the question of aberration cannot be certainly pronounced until the autumn observations shall have been made; but supposing the geodetic latitude to be accordant with the astronomical latitude, the result for aberration appears to be sensibly the same as with ordinary telescopes.--several years since, i prepared a barometer, by which the barometric fluctuations were enlarged, for the information of the public; its indications are exhibited on the wall, near to the entrance gate of the observatory. a card is now also exhibited, in a glass case near the public barometer, giving the highest and lowest readings of the thermometer in the preceding twenty-four hours.--those who have given attention to the history of terrestrial magnetism are aware that halley's magnetic chart is very frequently cited; but i could not learn that any person, at least in modern times, had seen it. at last i discovered a copy in the library of the british museum, and have been allowed to take copies by photolithography. these are appended to the magnetical and meteorological volume for 1869.--the trials and certificates of hand-telescopes for the use of the royal navy have lately been so frequent that they almost become a regular part of the work of the observatory. i may state here that by availing myself of a theory of eyepieces which i published long since in the cambridge transactions, i have been able to effect a considerable improvement in the telescopes furnished to the admiralty.--the occurrence of the total eclipse of the sun in december last has brought much labour upon the observatory. as regards the assistants and computers, the actual observation on a complicated plan with the great equatoreal (a plan for which few equatoreals are sufficiently steady, but which when properly carried out gives a most complete solution of the geometrical problem) has required, in observation and in computation, a large expenditure of time.--my preparations for the transit of venus have respect only to eye-observation of contact of limbs. with all the liabilities and defects to which it is subject, this method possesses the inestimable advantage of placing no reliance on instrumental scales. i hope that the error of observation may not exceed four seconds of time, corresponding to about 0.13" of arc. i shall be very glad to see, in a detailed form, a plan for making the proper measures by heliometric or photographic apparatus; and should take great interest in combining these with the eye-observations, if my selected stations can be made available. but my present impression is one of doubt on the certainty of equality of parts in the scale employed. an error depending on this cause could not be diminished by any repetition of observations."--after referring to the desirability of vigorously prosecuting the meteorological reductions (already begun) and of discussing the magnetic observations, the report concludes thus: "there is another consideration which very often presents itself to my mind; the waste of labour in the repetition of observations at different observatories..... i think that this consideration ought not to be put out of sight in planning the courses of different observatories."--in this year de launay's lunar theory was published. this valuable work was of great service to airy in the preparation of the numerical lunar theory, which he subsequently undertook.--in the latter part of this year airy was elected president of the royal society, and held the office during 1872 and 1873. at this time he was much pressed with work, and could ill afford to take up additional duties, as the following quotation from a letter to one of his friends shews: "the election to the presidency of r.s. is flattering, and has brought to me the friendly remembrances of many persons; but in its material and laborious connections, i could well have dispensed with it, and should have done so but for the respectful way in which it was pressed on me." of private history: there was the usual winter visit to playford.--in april he made a short trip to cornwall with his daughter annot.--in june he was appointed a companion of the bath, and was presented at court on his appointment.--mrs airy was staying with her daughter, mrs routh, at hunstanton, during june, her state of health being somewhat improved.--from august 1st to 28th he was chiefly in cumberland, at barrow house, and at grange, borrowdale, where his son osmund was staying for a holiday. 1872 "from the report to the board of visitors it appears that 'the normal siderial clock for giving sidereal time by galvanic communication to the astronomical observatory was established in the magnetic basement in 1871, june; that locality being adapted for it on account of the uniformity of temperature, the daily changed of temperature rarely exceeding 1â° fahrenheit. its escapement is one which i suggested many years ago in the cambridge transactions; a detached escapement, very closely analogous to the ordinary chronometer escapement, the pendulum receiving an impulse only at alternate vibrations.... the steadiness of rate is very far superior to any that we have previously attained.'--the aspect of railway enterprise is at present favourable to the park and to the observatory. the south-eastern railway company has made an arrangement with the metropolitan board of works for shifting the course of the great southern outfall sewer. this enables the company to trace a new line for the railway, passing on the north side of london street, at such a distance from the observatory as to remove all cause of alarm. i understand that the bill, which was unopposed, has passed the committee of the house of commons. i trust that the contest, which has lasted thirty-seven years, is now terminated.--the observations of 7 draconis with the water-telescope, made in the autumn of 1871, and the spring of 1872, are reduced, the latter only in their first steps.... using the values of the level scales as determined by mr simms (which i have no reason to believe to be inaccurate) the spring and autumn observations of 1871 absolutely negative the idea of any effect being produced on the constant of aberration by the amount of refracting medium traversed by the light.--the great aurora of 1872 feb. 4 was well observed. on this occasion the term borealis would have been a misnomer, for the phenomenon began in the south and was most conspicuous in the south. three times in the evening it exhibited that umbrella-like appearance which has been called (perhaps inaccurately) a corona. i have very carefully compared its momentary phenomena with the corresponding movements of the magnetometers. in some of the most critical times, the comparison fails on account of the violent movements and consequent faint traces of the magnetometers. i have not been able to connect the phases of aurora and those of magnetic disturbance very distinctly.--the report contains a detailed account of the heavy preparations for the observation of the transit of venus 1874, including the portable buildings for the instruments, the instruments themselves (being a transit-instrument, an altazimuth, and an equatoreal, for each station), and first class and second-class clocks, all sufficient for the equipment of 5 stations, and continues thus: i was made aware of the assent of the government to the wish of the board of visitors, as expressed at their last meeting, that provision should be made for the application of photography to the observation of the transit of venus. it is unnecessary for me to remark that our hope of success is founded entirely on our confidence in mr de la rue. under his direction, mr dallmeyer has advanced far in the preparation of five photoheliographs.... the subject is recognized by many astronomers as not wholly free from difficulties, but it is generally believed that these difficulties may be overcome, and mr de la rue is giving careful attention to the most important of them.--i take this opportunity of reporting to the board that the observatory was honoured by a visit of his majesty the emperor of brazil, who minutely examined every part."--after referring to various subjects which in his opinion might be usefully pursued systematically at the observatory, the report proceeds thus: "'the character of the observatory would be somewhat changed by this innovation, but not, as i imagine, in a direction to which any objection can be made. it would become, pro tanto, a physical observatory; and possibly in time its operations might be extended still further in a physical direction.'--the consideration of possible changes in the future of the observatory leads me to the recollection of actual changes in the past. in my annual reports to the visitors i have endeavoured to chronicle these; but still there will be many circumstances which at present are known only to myself, but which ought not to be beyond the reach of history. i have therefore lately employed some time in drawing up a series of skeleton annals of the observatory (which unavoidably partakes in some measure of the form of biography), and have carried it through the critical period, 1836-1851. if i should command sufficient leisure to bring it down to 1861, i think that i might then very well stop." (the skeleton annals here referred to are undoubtedly the manuscript notes which form the basis of the present biography. ed.)--"on feb. 23rd in this year i first (privately) formed the notion of preparing a numerical lunar theory by substituting delaunay's numbers in the proper equations and seeing what would come of it." of private history: there was the usual visit to playford--in this year later than usual--from feb. 4th to mar. 4th. the letters written during this visit are, as usual, full of freshness and delight at finding himself in his favourite country village.--on june 5th he went to barrow house, near keswick, to be present at the marriage of his second son hubert to miss s. c. langton, daughter of z. langton esq., of barrow house.--after the wedding he made a trip through the trossachs district of scotland with his daughter annot, and returned to greenwich on june 17th. on the 26th june 1872 airy was appointed a knight commander of the most honourable order of the bath: he was knighted by the queen at osborne on the 30th of july. in the course of his official career he had three times been offered knighthood, and had each time declined it: but it seemed now as if his scruples on the subject were removed, and it is probable that he felt gratified by the public recognition of his services. of course the occasion produced many letters of congratulation from his friends: to one of these he replied as follows: "the real charm of these public compliments seems to be, that they excite the sympathies and elicit the kind expressions of private friends or of official superiors as well as subordinates. in every way i have derived pleasure from these." from the assistants of the royal observatory he received a hearty letter of congratulation containing the following paragraph. "our position has naturally given us peculiar opportunities for perceiving the high and broad purposes which have characterized your many and great undertakings, and of witnessing the untiring zeal and self-denial with which they have been pursued." * * * * * on the 18th of march 1872 airy was nominated a foreign associate of the institut de france, to fill the place vacant by the death of sir john herschel. the following letter of acknowledgment shews how much he was gratified by this high scientific honour: royal observatory, greenwich, _1872, march 23_. _ã�_ messieurs messieurs elie de beaumont, _et_ j.b. dumas, _secrã©taires perpetuels de l'acadã©mie des sciences, institut de france._ gentlemen, i am honoured with your letter of march 18, communicating to me my nomination by the academy of sciences to the place rendered vacant in the class of foreign associates of the academy by the decease of sir john herschel, and enclosing copy of the decree of the president of the french republic approving the election. it is almost unnecessary for me to attempt to express to you the pride and gratification with which i receive this announcement. by universal consent, the title of _associã© etranger de l'acadã©mie des sciences_ is recognised as the highest distinction to which any man of science can aspire; and i can scarcely imagine that, unless by the flattering interpretation of my friends in the academy, i am entitled to bear it. but in any case, i am delighted to feel that the bands of friendship are drawn closer between myself and the distinguished body whom, partly by personal intercourse, partly by correspondence, and in every instance by reputation, i have known so long. i beg that you will convey to the academy my long-felt esteem for that body in its scientific capacity, and my deep recognition of its friendship to me and of the honor which it has conferred on me in the late election. i have the honor to be gentlemen, your very faithful servant, g.b. airy. * * * * * on the 20th november 1872 airy was nominated a grand cross in the imperial order of the rose of brazil: the insignia of the order were accompanied by an autograph letter from the emperor of brazil, of which the following is a transcript. monsieur, vous ãªtes un des doyens de la science, et le prã©sident de l'illustre sociã©tã©, qui a eu la bienveillance d'inscrire mon nom parmi ceux de ses associã©s. la maniã¨re, dont vous m'avez fait les honneurs de votre observatoire m'a imposã© aussi l'agrã©able devoir d'indiquer votre nom ã  l'empereur de brã©sil pour un tã©moignage de haute estime, dont je suis fort heureux de vous faire part personellement, en vous envoyant les dã©corations que vous garderez, an moins, comme un souvenir de ma visite ã  greenwich. j'espã¨re que vous m'informerez, quand il vous sera aisã©, des travaux de votre observatoire, et surtout de ce que l'on aura fait pour l'observation du passage de vã©nus et la dã©termination exacte de la passage. j'ai reã§u dã©jã  les _proceedings de la royal society_ lesquels m'intã©ressent vivement. je voudrais vous ã©crire dans votre langue, mais, comme je n'en ai pas l'habitude, j'ai craignã© de ne pas vous exprimer tout-ã -fait les sentiments de votre affectionnã©, d. pedro d'alcantara. rio, _22 octobre, 1872_. * * * * * airy's reply was as follows: royal observatory, greenwich, _1872, november 26_. sire, i am honoured with your imperial majesty's autograph letter of october 22 informing me that, on considering the attention which the royal society of london had been able to offer to your majesty, as well as the explanation of the various parts of the establishment of this observatory which i had the honor and the high gratification to communicate, you had been pleased to place my name in the imperial order of the rose, and to present to me the decorations of grand cross of that order. with pride i receive this proof of your majesty's recollection of your visit to the scientific institutions of great britain. the diploma of the appointment to the order of the rose, under the imperial sign manual, together with the decorations of the order, have been transmitted to me by his excellency don pereira de andrada, your majesty's representative at the british court. your majesty has been pleased to advert to the approaching transit of venus, on the preparations for which you found me engaged. it is unfortunate that the transit of 1874 will not be visible at rio de janeiro. for that of 1882, rio will be a favourable position, and we reckon on the observations to be made there. your majesty may be assured that i shall loyally bear in mind your desire to be informed of any remarkable enterprise of this observatory, or of any principal step in the preparations for the transit of venus and of its results. i have the honor to be sire, your imperial majesty's very faithful servant, g.b. airy. _to his majesty the emperor of brazil._ * * * * * airy's old friend, adam sedgwick, was now very aged and infirm, but his spirit was still vigorous, and he was warm-hearted as ever. the following letter from him (probably the last of their long correspondence) was written in this year, and appears characteristic: trinity college, cambridge, _may 10, 1872_. my dear airy, i have received your card of invitation for the 1st of june, and with great joy should i count upon that day if i thought that i should be able to accept your invitation: but alas i have no hope of the kind, for that humiliating malady which now has fastened upon me for a full year and a half has not let go its hold, nor is it likely to do so. a man who is journeying in the 88th year of his pilgrimage is not likely to throw off such a chronic malady. indeed were i well enough to come i am deaf as a post and half blind, and if i were with you i should only be able to play dummy. several years have passed away since i was last at your visitation and i had great joy in seeing mrs airy and some lady friends at the observatory, but i could not then attend the dinner. at that meeting were many faces that i knew, but strangely altered by the rude handling of old time, and there were many new faces which i had never seen before at a royal society meeting; but worse than all, all the old faces were away. in vain i looked round for wollaston, davy, davies gilbert, barrow, troughton, &c. &c.; and the merry companion admiral smyth was also away, so that my last visit had its sorrowful side. but why should i bother you with these old man's mopings. i send an old man's blessing and an old man's love to all the members of your family; especially to mrs airy, the oldest and dearest of my lady friends. i remain, my dear airy, your true-hearted old friend, his adam x sedgwick. mark p.s. shall i ever again gaze with wonder and delight from the great window of your observatory. the body of the above letter is in the handwriting of an amanuensis, but the signature and postscript are in sedgwick's handwriting. (ed.) * * * * * 1873 "chronographic registration having been established at the paris observatory, mr hilgard, principal officer of the american coast survey, has made use of it for determining the longitude of harvard from greenwich, through paris, brest, and st pierre. for this purpose mr hilgard's transit instrument was planted in the magnetic court. i understand that the result does not sensibly differ from that obtained by mr gould, through valentia and newfoundland.--it was known to the scientific world that several of the original thermometers, constructed by mr sheepshanks (in the course of his preparation of the national standard of length) by independent calibration of the bores, and independent determination of the freezing and boiling points on arbitrary graduations, were still preserved at the royal observatory. it was lately stated to me by m. tresca, the principal officer of the international metrical commission, that, in the late unhappy war in paris, the french original thermometers were destroyed; and m. tresca requested that, if possible, some of the original thermometers made by mr sheepshanks might be appropriated to the use of the international commission. i have therefore transferred to m. tresca the three thermometers a.6, s.1, s.2, with the documentary information relating to them, which was found in mr sheepshanks's papers; retaining six thermometers of the same class in the royal observatory.--the sidereal standard clock continues to give great satisfaction. i am considering (with the aid of mr buckney, of the firm of e. dent and co.) an arrangement for barometric correction, founded on the principle of action on the pendulum by means of a magnet which can be raised or lowered by the agency of a large barometer.--the altazimuth has received some important alterations. an examination of the results of observations had made me dissatisfied with the bearings of the horizontal pivots in their y's. mr simms, at my request, changed the bearings in y's for bearing in segments of circles, a construction which has worked admirably well in the pivots of the transit circle." (and in various other respects the instrument appears to have received a thorough overhauling. ed.)--"with the consent of the royal society and of the kew committee, the kew heliograph has been planted in the new dome looking over the south ground. it is not yet finally adjusted.--some magnetic observations in the britannia and conway tubular bridges were made last autumn. for this purpose i detached an assistant (mr carpenter), who was aided by capt. tupman, r.m.a.; in other respects the enterprise was private and at private expense.--the rates of the first six chronometers (in the annual trials) are published, in a form which appears most likely to lead to examination of the causes that influence their merits or demerits. this report is extensively distributed to british and foreign horologists and instrument-makers. all these artists appear to entertain the conviction that the careful comparisons made at this observatory, and the orderly form of their publication, have contributed powerfully to the improvement of chronometers.--very lately, application has been made to me, through the board of trade, for plans and other information regarding time-signal-balls, to assist in guiding the authorities of the german empire in the establishment of time signals at various ports of that state. in other foreign countries the system is extending, and is referred to greenwich as its origin.--the arrangements and preparations for the observation of the transit of venus occupied much attention. with regard to the photoheliographs it is proposed to make trial of a plan proposed by m. janssen, for numerous photographs of venus when very near to the sun's limb. on apr. 26th the engaging of photographic teachers was sanctioned. observers were selected and engaged. a working model of the transit was prepared, and the use of de la rue's scale was practised. there was some hostile criticism of the stations selected for the observation of the transit, which necessitated a formal reply.--reference is made to the increase of facilities for making magnetical and meteorological observations. the inevitable result of it is, that observations are produced in numbers so great that complete reduction becomes almost impossible. the labour of reduction is very great, and it is concluded that, of the enormous number of meteorological observations now made at numerous observatories, very few can ever possess the smallest utility.--referring to my numerical lunar theory: on june 30th, 1873, a theory was formed, nearly but not perfectly complete. numerical development of powers of aã·r and rã·a. factors of corrections to delaunay first attempted, but entirely in numerical form."--in march of this year airy was consulted by mr w.h. barlow, c.e., and mr thomas bouch (the engineer of the tay bridge, which was blown down in 1879, and of a proposed scheme for a forth bridge in 1873) on the subject of the wind pressure, &c., that should be allowed for in the construction of the bridge. airy's report on this question is dated 1873, apr. 9th: it was subsequently much referred to at the official enquiry into the causes of the failure of the tay bridge.--at the end of this year airy resigned the presidency of the royal society. in his address to the society on dec. 1st he stated his reasons in full, as follows: "the severity of official duties, which seem to increase, while vigour to discharge them does not increase; and the distance of my residence.... another cause is a difficulty of hearing, which unfits me for effective action as chairman of council." of private history: there was the usual visit to playford in january: also a short visit in may: and a third visit at christmas.--there was a short run in june, of about a week, to coniston, with one of his daughters.--and there was a trip to weymouth, &c., for about 10 days, with one of his daughters, in the beginning of august--on his return from the last-mentioned trip, airy found a letter from the secretary of the swedish legation, enclosing the warrant under the royal sign manual of his majesty (oscar), the king of sweden and norway, by which he was nominated as a first class commander of the order of the north star, and accompanying the decorations of that order. 1874 "in this year mr glaisher resigned his appointment: i placed his department (magnetical and meteorological) under mr ellis.--a balance of peculiar construction has been made by mr oertling, from my instructions, and fixed near the public barometer at the entrance gate. this instrument enables the public to test any ordinary pound weight, shewing on a scale the number of grains by which it is too heavy or too light.--fresh counterpoises have been attached to the great equatoreal to balance the additional weight of the new spectroscope, which was finally received from mr browning's hands on may 2nd of the present year. the spectroscope is specifically adapted to sweeping round the sun's limb, with a view to mapping out the prominences, and is also available for work on stars and nebulae, the dispersive power being very readily varied. an induction-coil, capable of giving a six-inch spark, has been made for this instrument by mr browning.--some new classes of reductions of the meteorological observations from 1848 to 1868 have been undertaken and completed in the past year. the general state of this work is as follows: the diurnal changes of the dry-bulb thermometer, as depending on the month, on the temperature waves, on the barometric waves, on the overcast and cloudless states of the sky, and on the direction of the wind, have been computed and examined for the whole period; and the exhibition of the results is ready for press. the similar reductions for the wet-bulb thermometer are rapidly approaching completion. --regarding the preparations for the transit of venus expeditions. originally five stations were selected and fully equipped with equatoreals, transits, altazimuths, photoheliographs, and clocks; but i have since thought it desirable to supplement these by two branch stations in the sandwich islands and one in kerguelen's island; and the additional instruments thus required have been borrowed from various sources, so that there is now an abundant supply of instrumental means.... there will thus be available for observation of the transit of venus 23 telescopes, nine of which will be provided with double-image-micrometers; and five photoheliographs; and for determination of local time, and latitude and longitude, there will be nine transits and six altazimuths.... all the observers have undergone a course of training in photography; first, under a professional photographer, mr reynolds, and subsequently under capt. abney, r.e., whose new dry-plate process is to be adopted at all the british stations.... a janssen slide, capable of taking 50 photographs of venus and the neighbouring part of the sun's limb at intervals of one second, has been made by mr dallmeyer for each of the five photoheliographs."--attached to the report to the visitors is a copy of the instructions to observers engaged in the transit of venus expeditions, prepared with great care and in remarkable detail.--"in the past spring i published in the monthly notices of the royal astronomical society a statement of the fundamental points in a new treatment of the lunar theory, by which, availing myself of all that has been done in the best algebraical investigations of that theory, i trust to be able by numerical operations only to give greater accuracy to final results. considerable progress has been made in the extensive numerical developments, the work being done, at my private expense, entirely by a junior computer; and i hope, at any rate, to put it in such a state that there will be no liability to its entire loss. when this was reported to the board of visitors, it was resolved on the motion of prof. stokes, that this work, as a public expense, ought to be borne by the government; and this was forwarded to the admiralty. on june 24th i wrote to the secretary of the admiralty, asking for _â£100_ for the present year, which after the usual enquiries and explanations was sanctioned on aug. 29th." of private history: there were short visits to playford in january, june, and october, but only for a few days in each case.--in march there was a run of two or three days to newnham (on the severn) to see the bore on the severn, and to malvern.--in july he went to newcastle to observe with mr newall's great telescope, but the weather was unfavourable: he then went on to barrow house near keswick, and spent a few days there, with excursions among the mountains.--on aug. 13th he went with his daughter christabel to the isle of arran, and then by glasgow to the trosachs, where he made several excursions to verify the localities mentioned in the "lady of the lake."--while in scotland he heard of the death of his brother, the rev. william airy, and travelled to keysoe in bedfordshire to attend the funeral; and returned to greenwich on aug. 24th. 1875 "in october of this year i wrote to the admiralty that i had grounds for asking for an increase of my salary: because the pension which had been settled on my wife, and which i had practically recognized as part of my salary, had been terminated by her death; so that my salary now stood lower by _â£200_ than that of the director of studies of the royal naval college. the admiralty reply favourably, and on nov. 27th the treasury raise my salary to _â£1_,200.--for the service of the clock movement of the great equatoreal, a water-cistern has been established in the highest part of the ball-turret, the necessity for which arose from the following circumstance: the water clock was supplied by a small pipe, about 80 feet in length, connected with the 3-inch observatory main (which passes through the park), at a distance of about 250 feet from any other branch pipe. in spite of this distance i have seen that, on stopping the water-tap in the battery-basement under the north-east turret, the pressure in the gauge of the water clock has been instantly increased by more than 40 lbs. per square inch. the consequent derangement of the water clock in its now incessant daily use became intolerable. since the independent supply was provided, its performance has been most satisfactory.--with the spectroscope the solar prominences have been mapped on 28 days only; but the weather of the past winter was exceptionally unfavourable for this class of observation. after mapping the prominences, as seen on the c line, the other lines, especially f and b, have been regularly examined, whenever practicable. great care has been taken in determining the position, angle, and heights of the prominences in all cases. the spectrum of coggia's comet was examined at every available opportunity last july, and compared directly with that of carbon dioxide, the bands of the two spectra being sensibly coincident. fifty-four measures of the displacement of lines in the spectra of 10 stars, as compared with the corresponding lines in the spectra of terrestrial elements (chiefly hydrogen), have been made, but some of these appear to be affected by a constant error depending on faulty adjustment of the spectroscope.--photographs of the sun have been taken with the kew photoheliograph on 186 days; and of these 377 have been selected for preservation. the moon, jupiter, saturn, and several stars (including the pleiades and some double stars) have been photographed with the great equatoreal, with fairly satisfactory results, though further practice is required in this class of work.--i would mention a supplemental mechanism which i have myself introduced into some chronometers. i have long remarked that, in ordinary good chronometers, the freedom from irregularities depending on mechanical causes is most remarkable; but that, after all the efforts of the most judicious makers, there is in nearly every case a perceptible defect of thermal compensation. there is great difficulty in correcting the residual fault, not only because an inconceivably small movement of the weights on the balance-curve is required, but also because it endangers the equilibrium of the balance. the mechanism adopted to remedy the defect is described in a paper in the horological journal of july 1875 by mr w. ellis, and has received the approval of some able chronometer-makers.--with respect to the transit of venus expeditions: the parties from egypt and rodriguez are returned. i am in continual expectation of the arrival of the other parties. i believe the eye-observations and the ordinary photographs to be quite successful; i doubt the advantage of the janssen; one of the double-image-micrometers seems to have failed; and the zenith-telescope gives some trouble. at three stations at rodriguez, and three at kerguelen, the observations appear to have been most successful. at the sandwich islands, two of the stations appear to have been perfectly successful (except that i fear that the janssen has failed), and a rich series of lunar observations for longitude is obtained. at new zealand, i grieve to say, the observations were totally lost, entirely in consequence of bad weather. there has been little annoyance from the dreaded 'black drop.' greater inconvenience and doubt have been caused by the unexpected luminous ring round venus.--with regard to the progress of my proposed new lunar theory: three computers are now steadily employed on the work. it will be remembered that the detail and mass of this work are purely numerical; every numerical coefficient being accompanied with a symbolical correction whose value will sometimes depend on the time, but in every case is ultimately to be obtained in a numerical form. of these coefficients, extracted (for convenience) from delaunay's results, there are 100 for parallax, 182 for longitude, 142 for latitude; the arguments being preserved in the usual form."--after reviewing the changes that had taken place at the observatory during the past forty years, the report to the board of visitors concludes thus: "i much desire to see the system of time-signals extended, by clocks or daily signals, to various parts of our great cities and our dockyards, and above all by hourly signals on the start point, which i believe would be the greatest of all benefits to nautical chronometry. should any extension of our scientific work ever be contemplated, i would remark that the observatory is not the place for new physical investigations. it is well adapted for following out any which, originating with private investigators, have been reduced to laws susceptible of verification by daily observation. the national observatory will, i trust, always remain on the site where it was first planted, and which early acquired the name of 'flamsteed hill.' there are some inconveniences in the position, arising principally from the limited extent of the hill, but they are, in my opinion, very far overbalanced by its advantages."--in a letter on the subject of the smith's prizes examination at cambridge, which was always a matter of the greatest interest to him, airy renewed his objections to the preponderance in the papers of a class of pure mathematics, which he considered was never likely under any circumstances to give the slightest assistance to physics. and, as before, these remarks called forth a rejoinder from prof. cayley, who was responsible for many of the questions of the class referred to.--in this year airy completed his "notes on the earlier hebrew scriptures," which were shortly afterwards published as a book by messrs longmans, green, & co. in his letter to the publishers introducing the subject, he says, "for many years past i have at times put together a few sentences explanatory as i conceive of the geographical and historical circumstances connected with the principal events recorded in the hebrew scriptures. the view which i take is free, but i trust not irreverent. they terminate with a brief review of colenso's great work. the collection now amounts to a small book." from the references already given in previous years to his papers and correspondence on the geography of exodus, his correspondence with colenso, &c. &c., it will be seen that he took a great interest in the early history of the israelites.--on august 10th, 1875, airy celebrated the bicentenary of the royal observatory by a dinner in the octagon room, which was attended by the presidents of the royal society and the r. astr. society, and by a large number of scientific gentlemen interested in astronomy.--in february he was revising his treatise on "probabilities." of private history: up to jan. 16th airy was at playford as usual.--for about a week in april he was in the isle of man with his daughter christabel.--in june there was a short trip to salisbury, blandford, and wimborne.--on august 12th he started with his daughter annot for a holiday in cumberland, but on the next day he was recalled by a telegram with the intelligence that a change for the worse had come over his wife's health. lady airy died on august 13th, 1875. for the last five years of her life she had been very helpless from the effects of a paralytic stroke--a very sad ending to a bright and happy life--and had been continually nursed throughout this time by her two unmarried daughters with the greatest self-denial and devotion. her husband had been unremitting in his care and attention. nothing was wanting that the most thoughtful kindness could supply. and in all his trips and excursions his constant and kind letters shewed how anxious he was that she should participate in all his interests and amusements. from the nature of the case it could hardly be said that her death was unexpected, and he received the shock with the manly steadiness which belonged to him. lady airy was buried in playford churchyard.--from sept. 22nd to oct. 4 he made a short expedition to wales (capel curig, &c.).--on dec. 15th he attended the commemoration at trinity college, cambridge.--on dec. 22nd he went as usual to playford. in this year airy received the high honour of the freedom of the city of london, in the following communication: stone, mayor.--a common council holden in the chamber of the guildhall of the city of london, on thursday the 29th day of april 1875. resolved unanimously that the freedom of this city in a gold box of the value of one hundred guineas be presented to sir george biddell airy, k.c.b., d.c.l., ll.d. &c., astronomer royal, as a recognition of his indefatigable labours in astronomy, and of his eminent services in the advancement of practical science, whereby he has so materially benefited the cause of commerce and civilization. monckton. this resolution was forwarded with a letter from benjamin scott, the chamberlain. airy's reply was as follows: royal observatory, greenwich, s.e. _1875, may 1_. dear sir, i have the honour to acknowledge your letter of april 30, accompanied with copy of the resolution of the common council of the city of london passed at their meeting of april 29, under signature of the town clerk, that the freedom of the city of london in a valuable box be presented to me, in recognition of works stated in the resolution. and i am requested by you to inform you whether it is my intention to accept the compliment proposed by the corporation. in reply, i beg you to convey to the right honorable the lord mayor and the corporation that i accept with the greatest pride and pleasure the honour which they propose to offer to me. the freedom of our great city, conferred by the spontaneous act of its municipal governors, is in my estimation the highest honour which it is possible to receive; and its presentation at this time is peculiarly grateful to me. i have the honour to be, sir, your very obedient servant, g.b. airy. _benjamin scott, esq., &c. &c. &c. chamberlain of the corporation of the city of london._ as it was technically necessary that a freeman of the city of london should belong to one or other of the city companies, the worshipful company of spectacle makers through their clerk (with very great appropriateness) enquired whether it would be agreeable that that company should have the privilege of conferring their honorary freedom on him, and added: "in soliciting your acquiescence to the proposal i am directed to call attention to the fact that this guild is permitted to claim all manufacturers of mathematical and astronomical instruments within the city of london, which is now pleaded as an apology for the wish that one so distinguished as yourself in the use of such instruments should be enrolled as a member of this craft." in his reply, accepting the freedom of the company, airy wrote thus: "i shall much value the association with a body whose ostensible title bears so close a relation to the official engagements which have long occupied me. i have had extensive experience both in arranging and in using optical and mathematical instruments, and feel that my own pursuits are closely connected with the original employments of the company." the freedom of the company was duly presented, and the occasion was celebrated by a banquet at the albion tavern on tuesday, july 6th. the freedom of the city of london was conferred at a court of common council held at the guildhall on thursday the 4th of november. in presenting the gold box containing the freedom, the chamberlain, in an eloquent speech, first referred to the fact that this was the first occasion on which the freedom had been conferred on a person whose name was associated with the sciences other than those of war and statecraft. he then referred to the solid character of his work, in that, while others had turned their attention to the more attractive fields of exploration, the discovery of new worlds or of novel celestial phenomena, he had incessantly devoted himself to the less interesting, less obtrusive, but more valuable walks of practical astronomy. and he instanced as the special grounds of the honour conferred, the compilation of nautical tables of extraordinary accuracy, the improvement of chronometers, the correction of the compasses of iron ships, the restoration of the standards of length and weight, and the transit of venus expeditions. in his reply airy stated that he regarded the honour just conferred upon him as the greatest and proudest ever received by him. he referred to the fact that the same honour had been previously conferred on the valued friend of his youth, thomas clarkson, and said that the circumstance of his succeeding such a man was to himself a great honour and pleasure. he alluded to his having received a small exhibition from one of the london companies, when he was a poor undergraduate at cambridge, and acknowledged the great assistance that it had been to him. with regard to his occupation, he said that he had followed it in a great measure because of its practical use, and thought it fortunate that from the first he was connected with an institution in which utility was combined with science. the occasion of this presentation was celebrated by a banquet at the mansion house on saturday july 3rd, 1875, to sir george airy (astronomer royal) and the representatives of learned societies. there is no doubt that airy was extremely gratified by the honour that he had received. it was to him the crowning honour of his life, and coming last of all it threw all his other honours into the shade. to his independent and liberal spirit there was something peculiarly touching in the unsolicited approbation and act of so powerful and disinterested a body as the corporation of the city of london. chapter ix. at greenwich observatory from january 1st, 1876, to his resignation of office on august 15th, 1881. 1876 "at the door from the front court to the staircase of the octagon room (the original entrance to the observatory as erected by sir christopher wren), a small porch-shelter has been often desired. i proposed to fix there a fan-roof of quadrantal form, covering the upper flat stone of the external steps.--on a critical examination of the micrometer-screws of the transit circle it was found that the corrections, which range from -1â°38" to +0â°76", indicate considerable wear in the screws; and it was found that as much as one-hundreth part of an inch had been worn away from some of the threads. the old screws were consequently discarded, and new ones were made by mr simms.--the adjustment of the spectroscope has occupied a great deal of attention. there was astigmatism of the prisms; and false light reflected from the base of the prisms, causing loss both of light and of definition. the latter defect was corrected by altering the angles, and then astigmatism was corrected by a cylindrical lens near the slit. the definition in both planes was then found to be perfect.--the number of small planets has now become so great, and the interest of establishing the elements of all their orbits so small,--while at the same time the light of all those lately discovered is very faint, and the difficulty and doubt of observation greatly increased,--that i have begun to think seriously of limiting future observations to a small number of these objects.--all observations with the spectroscope have been completely reduced; the measures of lines in the spectra of elements being converted into corresponding wave-lengths, and the observations of displacement of lines in the spectra of stars being reduced so as to exhibit the concluded motion in miles per second, after applying a correction for the earth's motion. sixteen measures of the f line in the spectrum of the moon as compared with hydrogen give a displacement corresponding to a motion of less than two miles a second, which seems to shew that the method of comparison now adopted is free from systematic error; and this is supported by the manner in which motions of approach and recession are distributed among the stars examined on each night of observation. the results recently obtained appear to be on the whole as consistent as can be expected in such delicate observations, and they support in a remarkable manner the conclusions of dr huggins, with regard to the motions of those stars which he examined.--photographs of the sun have been taken with the photoheliograph on 182 days. on one of the photographs, which was accidentally exposed while the drop slit was being drawn up, there appears to be a faint image of a cloud-like prominence close to the sun's limb, though the exposure probably only amounted to a fraction of a second. a prominence of unusual brilliancy was seen with the spectroscope about the same time and in the same position with reference to the sun's limb. all groups of sun-spots and faculae have been numbered, and the dates of their first and last appearances entered up to the present time. areas of spots have been measured, and the measures have been reduced to millionths of the sun's visible hemisphere.--the examination of the readings of the deep-sunk thermometers from 1846 to 1873 has exhibited some laws which had been sufficiently established before this time, and some which were less known. among the former were the successive retardations of seasons in successive descents, amounting to about four months at the depth of 25 feet; and the successive diminutions of the annual range of temperature. among the latter is the character of the changes from year to year, which the great length of this series of observations brings well to light. it is found that from year to year the mean temperature of the surface for the year, varying by three or four degrees of fahrenheit, follows in its changes the mean temperature of the atmosphere for the year, and that the changes of annual temperature are propagated downwards, retarded in phase and diminishing in amount of change, in the same manner (though probably not following the same law) as the season changes. the inference from this is, that changes of temperature come entirely from the exterior and in no discoverable degree from the interior; an inference which may be important in regard both to solar action and to geology. --referring to the transit of venus observations: in the astronomical part of the reductions, there has been great labour and difficulty in the determination of local sidereal times; some books of observations required extensive transcription; some instrumental errors are still uncertain; the latter determinations have perplexed us so much that we are inclined to believe that, in spite of the great facilities of reduction given by the transit instrument, it would be better to rely on the altazimuth for time-determinations.... in the photographic part, i have confined my attention entirely to measures of the distance between the centres of the sun and planet, a troublesome and complex operation.--referring to the progress of the numerical lunar theory: with a repetition of grant from the treasury, i have usually maintained four junior computers on this work. the progress, though considerable, has not been so great as i had hoped, by reason of the excessive personal pressure upon me during the whole year.--i wrote a letter of congratulation to le verrier on the completion of his great work of planetary tables.--on may 13th the queen was at south kensington, and i attended to explain the astronomical instruments, and shewed her majesty one of the transit of venus photographs." of private history: he returned from his playford visit on the 18th of january.--in april there was a two-day trip to colchester.--from june 13th to july 12th he was travelling in the north of scotland and the orkneys with his daughters, staying for a short time with mr webster, m.p., at aberdeen, and with mr newall at newcastle.--in september there was a week's run to birkenhead and keswick.--in november a week's run to playford.--from the 13th to 15th of december he was at cambridge, and on the 28th he went to playford for the usual winter stay there. 1877 "in april of this year i was much engaged on the subject of mr gill's expedition to ascension to observe for the determination of the parallax of mars at the approaching opposition of that planet.--a large direct-vision spectroscope has been quite recently made by mr hilger under mr christie's direction on a new plan, in which either great dispersion or great purity of spectrum is obtained by the use of 'half-prisms,' according as the incident pencil falls first on the perpendicular or on the oblique face. in this spectroscope either one or two half prisms can be used at pleasure, according to the dispersion required, and there is facility for increasing the train to three or four half-prisms, though the dispersion with two only is nearly double of that given by the large ten-prism spectroscope. the definition in this form of spectroscope appears to be very fine.--at the end of may 1876, spectroscopic determinations of the sun's rotation were made by observations of the relative displacement of the fraunhofer lines at the east and west limbs respectively. the results are in close agreement with the value of the rotation found from observations of sun-spots. a similar determination has also been made in the case of jupiter, with equally satisfactory results.--an electrometer on sir william thomson's plan, for continuous photographic registration of atmospheric electricity has been received from mr white of glasgow. it was mounted in december.--the computation of the photographic records of the barometer from 1854 to 1873 has so far advanced that we can assert positively that there is no trace of lunar tide in the atmosphere; but that there is a strongly marked semi-diurnal solar tide, accompanied with a smaller diurnal tide. we are at present engaged in comparing the barometric measures with the directions of the wind.--regarding the distribution of the printed observations: there is no extensive wish for separate magnetic observations, but general magnetic results are in great demand, especially for mining operations, and to meet this a map of magnetic declination is furnished in the newspaper called the 'colliery guardian.'--as regards the operations for the transit of venus: the computing staff has by degrees been reduced to two junior computers within the observatory; and one or two computers external to the observatory, who are employed on large groups of systematic calculations. the principal part of the calculations remaining at the date of the last report was that applying to the determination of the geographical longitudes of fundamental stations. at the moment of my writing, the last of these (the longitude of observatory bay, kerguelen) is not absolutely finished:... the method of determining the geographical longitude of the principal station in each group by vertical transits of the moon has been found very successful at honolulu and rodriguez. for stations in high south latitude, horizontal transits are preferable.--as regards the numerical lunar theory: with the view of preserving, against the ordinary chances of destruction or abandonment, a work which is already one of considerable magnitude, i have prepared and have printed as appendix to the greenwich observations (with additional copies as for a separate work) the ordinary equations of lunar disturbance, the novel theory of symbolical variations, and the numerical developments of the quantities on the first side of the equations.--at various times from february to may i was engaged on the reduction of malta tides, and on a paper concerning the same.--in july i was awarded the albert medal for my compass corrections, and received the same from the prince of wales.--in february, campbell's instrument for the registration of sunshine was introduced: it was mounted in july." of private history: "i was at playford until jan. 19th, in close correspondence as usual with mr christie at the observatory, and attending to my numerical lunar theory.--from mar. 29th to apr. 2nd i went on a short trip to hereford, worcester, &c.--from june 8th to 20th i was at playford.--from aug. 13th to sept. 8th airy was on an expedition in ireland, chiefly in the north and west, with his daughters. when at dublin he visited grubb's instrument factory. on the return journey he stayed for some time in the lake district of cumberland, and took soundings in the neighbourhood of the place of the 'floating island' in derwentwater." airy took the greatest interest in antiquarian matters, whether military or ecclesiastical, and his feelings on such matters is well illustrated by the following letter: royal observatory, greenwich, s.e. _1877, february 27_. dear sir, i venture to ask if you can assist me in the following matter. in the parish church of playford, near ipswich, suffolk, was a splendid brass tombstone to sir thomas felbrigg. by an act of folly and barbarism, almost unequalled in the history of the world, the incumbent and curate nearly destroyed the brass inscription surrounding the image of the knight. this tombstone is figured in gough's sepulchral antiquities, which, i presume, is to be found in the british museum. and i take the liberty to ask if you would kindly look at the engraving, and give me any suggestion as to the way in which some copies of it could be made, in a fairly durable form. i am connected with the parish of playford, and am anxious to preserve for it this memorial of a family of high rank formerly resident there. i am, dear sir, very faithfully yours, g.b. airy. _t. winter jones, esq._ to this request mr winter jones immediately acceded, and the engraving was duly photographed, and copies were circulated with a historical notice of sir george (not sir thomas) felbrigg and a history of the monument. sir george felbrigg was esquire-at-arms to edward iii., and lord of the manor of playford: he died in 1400, and was buried in the north wall of playford church. 1878 the report to the board of visitors has this paragraph: "i continue to remark the approaching necessity for library extension. without having absolutely decided on a site, i may suggest that i should wish to erect a brick building, about 50 feet by 20, consisting of two very low stories (or rather of one story with a gallery running round its walls), so low that books can be moved by hand without necessity for a ladder.--in the month of december, 1877, the azimuthal error of the transit circle had increased to 10". a skilful workman, instructed by mr simms, easily reduced the error to about 2".5 (which would leave its mean error nearly 0), the western y being moved to the north so far as to reduce the reading of the transit micrometer, when pointed to the south, from 35r.500 to 35r.000. the level error was not sensibly affected.--the sidereal standard clock preserves a rate approaching to perfection, so long as it is left without disturbance of the galvanic-contact springs (touched by its pendulum), which transmit signals at every second of time to sympathetic clocks and the chronograph. a readjustment of these springs usually disturbs the rate.--to facilitate the observations of stars, a new working catalogue has been prepared, in which are included all stars down to the third magnitude, stars down to the fifth magnitude which have not been observed in the last two catalogues, and a list of 258 stars of about the sixth magnitude of which the places are required for the united states coast survey. the whole number of stars in our new working list is about 2500. it may be here mentioned that an extensive series of observations was made, during the autumn, of about 70 stars, at the request of mr gill, for comparison with mars, ariadne, and melpomene.--on apr. 10th last, a very heavy fall of rain took place. between apr. 10d. 5h. and apr. 11d. 2h., 2.824 inch. was recorded, and 75 per cent. of this, or 2.12 inch., fell in the eight hours between 13-1/2h. and 21-1/2h.; and on may 7, 1 inch of rain fell in 50 minutes, of which 1/2 inch fell in 15 minutes.--the supplementary compensation continues to be applied with success to government chronometers which offer facilities for its introduction, and a marked improvement in the performance of chronometers returned after repair by the makers appears to have resulted from the increased attention now given to the compensation. of the 29 competitive chronometers, 25 have the supplementary compensation."--with regard to the reduction of the observations of the transit of venus: after reference to the difficulties arising from the errors and the interpretation of the language used by some of the observers, the report continues thus: "finally a report was made to the government on july 5th, giving as the mean result for mean solar parallax 8".76; the results from ingress and from egress, however, differing to the extent of 0".11.... after further examination and consideration, the result for parallax has been increased to 8".82 or 8".83. the results from photography have disappointed me much. the failure has arisen, perhaps sometimes from irregularity of limb, or from atmospheric distortion, but more frequently from faintness and from want of clear definition. many photographs, which to the eye appeared good, lost all strength and sharpness when placed under the measuring microscope. a final result 8".17 was obtained from mr burton's measures, and 8".08 from capt. tupman's.--with regard to the numerical lunar theory: a cursory collection of the terms relating to the areas (in the ecliptic) led me to suppose that there might be some error in the computations of the annual equation and related terms. a most jealous re-examination has however detected nothing, and has confirmed my belief in the general accuracy of the numerical computations. i dare not yet venture to assume an error in delaunay's theory; but i remember that the annual equation gave great trouble to the late sir john lubbock, and that he more than once changed his conclusions as to its true value.--in february i was engaged on the drawings and preparations for my intended lecture at cockermouth on the probable condition of the interior of the earth. the lecture was delivered in april.--at different times in the autumn i was engaged on diagrams to illustrate the passage of rays through eye-pieces and double-image micrometers.--the miscellaneous scientific correspondence, which was always going on, was in this year unusually varied and heavy." of private history: he was at playford till jan. 26th.--in april he went to cockermouth to deliver his lecture above-mentioned: the journey was by birmingham, where he stayed for two days (probably with his son osmund, who resided there), to tarn bank (the residence of isaac fletcher, m.p.): the lecture was delivered on the 22nd: he made excursions to thirlmere and barrow, and to edward i.'s monument, and returned to greenwich on the 27th.--from june 17th to 28th he was at playford.--from aug. 19th to sept. 17th he was travelling in scotland, visiting the tay bridge, the loch katrine waterworks, &c., and spent the last fortnight of his trip at portinscale, near keswick. on dec. 23rd he went to playford. 1879 "the manuscripts of every kind, which are accumulated in the ordinary transactions of the observatory, are preserved with the same care and arranged on the same system as heretofore. the total number of bound volumes exceeds 4000. besides these there is the great mass of transit of venus reductions and manuscripts, which when bound may be expected to form about 200 volumes.--with regard to the numerous group of minor planets, the berlin authorities have most kindly given attention to my representation, and we have now a most admirable and comprehensive ephemeris. but the extreme faintness of the majority of these bodies places them practically beyond the reach of our meridian instrument, and the difficulty of observation is in many cases further increased by the large errors of the predicted places.--after a fine autumn, the weather in the past winter and spring has been remarkably bad. more than an entire lunation was lost with the transit circle, no observation of the moon on the meridian having been possible between january 8 and march 1, a period of more than seven weeks. neither sun nor stars were visible for eleven days, during which period the clock-times were carried on entirely by the preceding rate of the clock. the accumulated error at the end of this time did not exceed 0s'3.--some difficulty was at first experienced with the thomson electrometer, which was traced to want of insulation. this has been mastered by the use of glass supporters, which carry some sulphuric acid. the instrument is now in excellent order, and the photographic registers have been perfectly satisfactory since 1879, february, when the new insulators were applied.--from the annual curves of diurnal inequality, deduced from the magnetic reductions, most important inferences may be drawn, as to the connection between magnetic phenomena and sun-spots. these annual curves shew a well-marked change in close correspondence with the number of sun-spots. about the epoch of maximum of sun-spots they are large and nearly circular, having the same character as the curves for the summer months; whilst about the time of sun-spot minimum they are small and lemniscate-shaped, with a striking resemblance to the curves for the winter months. the connection between changes of terrestrial magnetism and sun-spots is shewn in a still more striking manner by a comparison which mr ellis has made between the monthly means of the diurnal range of declination and horizontal force, and dr r. wolf's 'relative numbers' for frequency of sun-spots.--the records of sunshine with campbell's registering sun-dial are preserved in a form easily accessible for reference, and the results are communicated weekly to the agricultural gazette.--prof. oppolzer's results for the determination of the longitudes of vienna and berlin, made in 1877, have now been made public. they shew a remarkable agreement of the chronometric determination formerly made with the telegraphic. it may be of interest to recall the fact that a similar agreement was found between the chronometric and telegraphic determinations of the longitude of valentia.--for observing the transit of venus of 1882, the general impression appears to be that it will be best to confine our observations to simple telescopic observations or micrometer observations at ingress and egress, if possible at places whose longitudes are known. for the first phenomenon (accelerated ingress) the choice of stations is not good; but for the other phenomena (retarded ingress, accelerated egress, retarded egress) there appears to be no difficulty.--with regard to the numerical lunar theory: respecting the discordance of annual equation, i suspend my judgment. i have now discussed the theory completely; and in going into details of secular changes, i am at this time engaged on that which is the foundation of all, namely, the change of excentricity of the solar orbit, and its result in producing lunar acceleration. an important error in the theoretical formulae for variations of radius vector, longitude, and latitude, was discovered; some calculations depending on them are cancelled."--referring to the magnitude of the printed volume of "greenwich observations," and the practicability of reducing the extent of it, the report states thus: "the tendency of external scientific movement is to give great attention to the phenomena of the solar disc (in which this observatory ought undoubtedly to bear its part). and i personally am most unwilling to recede from the existing course of magnetical and meteorological observations....the general tendency of these considerations is to increase the annual expenses of the observatory. and so it has been, almost continuously, for the last 42 years. the annual ordinary expenses are now between 2-1/2 and 3 times as great as in my first years at the royal observatory.--mr gill was appointed to the cape observatory, and i wrote out instructions for him in march: there was subsequently much correspondence respecting the equipment and repairs of the cape observatory."--in the monthly notices of the royal astronomical society for january an article had appeared headed "notes on the late admiral smyth's cycle of celestial objects, vol. ii." by mr herbert sadler. in this article mr sadler had criticized the work of admiral smyth in a manner which airy regarded as imputing bad faith to admiral smyth. he at once took up the defence of his old friend very warmly, and proposed certain drafts of resolutions to the council of the society. these resolutions were moved, but were amended or negatived, and airy immediately resigned his office of vice-president. there was considerable negociation on the subject, and discussion with lord lindsay, and on may 9th airy's resolutions were accepted by the council.--in october airy inspected the "faraday" telegraph ship, then lying in the river near messrs siemens' works, and broke his finger by a fall on board the vessel.--in this year airy wrote and circulated a letter to the members of the senate of the university of cambridge, on the subject of the papers set in the smith's prizes examination. in this letter, as on former occasions, he objected much to the large number of questions in "purely idle algebra, arbitrary combinations of symbols, applicable to no further purpose." and in particular he singled out for comment the following question, which was one of those set, "using the term circle as extending to the case where the radius is a pure imaginary, it is required to construct the common chord of two given circles." this drew forth as usual a rejoinder from prof. cayley, who wrote enclosing a solution of his problem, but not at all to airy's satisfaction, who replied as follows: "i am not so deeply plunged in the mists of impossibles as to appreciate fully your explanation in this instance, or to think that it is a good criterion for university candidates." of private history: on jan. 21st he returned from playford.--on march 22nd he attended the funeral of his sister at little welnetham near bury st edmunds: miss elizabeth airy had lived with him at the observatory from shortly after his appointment.--for about a week at the end of april he was visiting matlock, edensor, and buxton.--from june 14th to july 18th he was staying at portinscale near keswick.--he was at playford for two or three days in october, and went there again on dec. 23rd for his usual winter holiday. the following letter, relating to the life of thomas clarkson, was written to dr merivale, dean of ely, after reading the account in the "times" of october 10th of the unveiling of a statue of clarkson near ware: royal observatory, greenwich, london, s.e. _1879, october 11_. dear sir, pardon my intrusion on you, in reference to a transaction which has greatly interested me--the honour paid by you to the memory of thomas clarkson. with very great pleasure i have heard of this step: and i have also been much satisfied with the remarks on it in the "times." i well remember, in clarkson's "history of the abolition," which i read some 60 years ago, the account of the circumstance, now commemorated by you, which determined the action of his whole subsequent life. it is not improbable that, among those who still remember clarkson, my acquaintance with him began at the earliest time of all. i knew him, intimately, from the beginning of 1815 to his death. the family which he represented must have occupied a very good position in society. i have heard that he sold two good estates to defray the expenses which he incurred in his personal labours for abolition: and his brother was governor of sierra leone (i know not at what time appointed). thomas clarkson was at st john's college; and, as i gather from circumstances which i have heard him mention, must have been a rather gay man. he kept a horse, and at one time kept two. he took orders in the church; and on one occasion, in the course of his abolition struggle, he preached in a church. but he afterwards resolutely laid aside all pretensions to the title of minister of the church, and never would accept any title except as layman. he was, however, a very earnest reader of theology during my acquaintance with him, and appeared to be well acquainted with the early fathers. the precise words in which was announced the subject for prize essay in the university were "anne liceat invitos in servitutem trahere." after the first great victory on the slave trade question, he established himself in a house on the bank of ullswater. i have not identified the place: from a view which he once shewed me i supposed it to be near the bottom of the lake: but from an account of the storm of wind which he encountered when walking with a lady over a pass, it seemed to be in or near patterdale. when the remains of a mountaineer, who perished in helvellyn (as described in scott's well-known poem), were discovered by a shepherd, it was to mr clarkson that the intelligence was first brought. he then lived at bury st edmunds. mrs clarkson was a lady of bury. but i cannot assign conjecturally any dates to his removals or his marriage. his only son took his b.a. degree, i think, about 1817. i think it was in 1814 that he began his occupation of playford hall--a moated mansion near ipswich, formerly of great importance --where he lived as gentleman farmer, managing a farm leased from the marquis of bristol, and occupying a good position among the gentry of the county. a relative of mine, with whom i was most intimately acquainted, lived in the same parish (where in defiance of school rules i spent nearly half my time, to my great advantage as i believe, and where i still retain a cottage for occasional residence), and i enjoyed much of mr clarkson's notice. it was by his strong advice that i was sent to cambridge, and that trinity college was selected: he rode with me to rev. mr rogers of sproughton for introductory examination; he introduced me to rev. c. musgrave (subsequently of halifax), accidentally doing duty at grundisburgh, who then introduced me to sedgwick, peacock, and t. musgrave (subsequently of york). in 1825, when i spent the summer at keswick, he introduced me to southey and wordsworth. mr clarkson lived about thirty years at playford hall, and died there, and lies interred with his wife, son, and grandson, in playford churchyard. i joined several friends in erecting a granite obelisk to his memory in the same churchyard. his family is extinct: but a daughter of his brother is living, first married to t. clarkson's son, and now mrs dickinson, of the rectory, wolferton. i am, my dear sir, very faithfully yours, g.b. airy. _the very reverend, the dean of ely._ 1880 "the admiralty, on final consideration of the estimates, decided not to proceed with the erection of a new library near the magnetic observatory in the present year. in the mean time the space has been cleared for the erection of a building 50 by 20 feet.--i have removed the electrometer mast (a source of some expense and some danger), the perfect success of sir william thomson's electrometer rendering all further apparatus for the same purpose unnecessary.--many years ago a double-image micrometer, in which the images were formed by the double refraction of a sphere of quartz, was prepared by mr dollond for capt. smyth, r.n. adopting the same principle on a larger scale, i have had constructed by mr hilger a micrometer with double refraction of a sphere of iceland spar. marks have been prepared for examination of the scale, but i have not yet had opportunity of trying it.--the spectroscopic determination of star-motions has been steadily pursued. the stars are taken from a working list of 150 stars, which may eventually be extended to include all stars down to the fourth magnitude, and it is expected that in the course of time the motions of about 300 stars may be spectroscopically determined.--a new pressure-plate with springs has been applied by mr browning to osler's anemometer, and it is proposed to make such modification as will give a scale extending to 50 lbs. pressure on the square foot. other parts of the instrument have also been renewed.--as regards the reduction of the magnetical results since 1863: in the study of the forms of the individual curves; their relations to the hour, the month, the year; their connection with solar or meteorological facts; the conjectural physico-mechanical causes by which they are produced; there is much to occupy the mind. i regret that, though in contemplation of these curves i have remarked some singular (but imperfect) laws, i have not been able to pursue them.--the mean temperature of the year 1879 was 46.1â°, being 3.3â° below the average of the preceding 38 years. the highest temperature was 80.6â° on july 30, and the lowest 13.7â° on dec. 7. the mean temperature was below the average in every month of the year; the months of greatest deviation being january and december, respectively 6.8â° and 7.6â° below the average; the months of april, may, july, and november were each between 4â° and 5â° below the average. the number of hours of bright sunshine, recorded with campbell's sunshine instrument, during 1879, was only 983.--in the summer of 1879 commander green, u.s.n., came over to this country for the purpose of determining telegraphically the longitude of lisbon, as part of a chain of longitudes extending from south america to greenwich. a successful interchange of signals was made with commander green between greenwich and porthcurno on four nights, 1879, june 25 to 29. the results communicated by commander green shew that the longitude of lisbon observatory, as adopted in the nautical almanac, requires the large correction of +8.54".--with regard to the coming transit of venus in 1882: from the facility with which the requirements for geographical position are satisfied, and from the rapid and accurate communication of time now given by electric telegraph, the observation of this transit will be comparatively easy and inexpensive. i have attached greater importance than i did formerly to the elevation of the sun.... i remark that it is highly desirable that steps be taken now for determining by telegraph the longitude of some point of australia. i have stated as the general opinion that it will be useless to repeat photographic observations. --in april mr barlow called, in reference to the enquiry on the tay bridge disaster. (the bridge had been blown down on dec. 28th, 1879.) i prepared a memorandum on the subject for the tay bridge commission, and gave evidence in a committee room of the house of lords on apr. 29th." (much of the astronomer royal's evidence on this occasion had reference to the opinions which he had expressed concerning the wind-pressure which might be expected on the projected forth bridge, in 1873.)--in may airy was consulted by the postmaster-general in the matter of a dispute which had arisen between the post office and the telephone companies, which latter were alleged to have infringed the monopoly of the post office in commercial telegraphs: airy made a declaration on the subject.--in july mr bakhuyzen came to england to determine the longitude of leyden, on which he was engaged till sept. 9th, and carried on his observations at the observatory.--in july airy was much engaged in perusing the records of mr gill's work at the cape of good hope. of private history: on jan. 24th he returned from playford.--from june 14th to july 4th he was again at playford.--from september 21st to october 20th he was staying at portinscale near keswick.--on dec. 23rd he went again to playford for his winter holiday. respecting the agitation at cambridge for granting university degrees to women, the following extract from a letter addressed to a young lady who had forwarded a memorial on the subject for his consideration, and dated nov. 10th, 1880, contains airy's views on this matter. "i have not signed the memorial which you sent for my consideration: and i will endeavour to tell you why. i entirely approve of education of young women to a higher pitch than they do commonly reach. i think that they can successfully advance so far as to be able clearly to understand--with gratification to themselves and with advantage to those whose education they will superintend--much of the results of the highest class of science which have been obtained by men whose lives are in great measure devoted to it. but i do not think that their nature or their employments will permit of their mastering the _severe_ steps of beginning (and indeed all through) and the _complicated_ steps at the end. and i think it well that this their success should be well known--as it is sure to be--among their relatives, their friends, their visitors, and all in whom they are likely to take interest. their connection with such a place as girton college is i think sufficient to lead to this. but i desire above all that all this be done in entire subservience to what i regard as _infinitely_ more valuable than any amount of knowledge, namely the delicacy of woman's character. and here, i think, our views totally separate. i do not imagine that the university degree would really imply, as regards education, anything more than is known to all persons (socially concerned in the happiness of the young woman) from the less public testimonial of the able men who have the means of knowing their merits. and thus it appears to me that the admission to university degree would simply mean a more extended publication of their names. i dread this." 1881 "the new line of underground telegraph wires has been completed by the officers of the general post office. the new route is down croom's hill in greenwich, and the result of this change, at least as regards the earth-current wires, and probably as regards the other wires, has not been satisfactory. it was soon found that the indications of the earth-current wires were disturbed by a continual series of petty fluctuations which almost completely masked the proper features of earth currents.... if this fault cannot be removed, i should propose to return to our original system of independent wires (formerly to croydon and dartford).--the new azimuth-mark (for the altazimuth), upon the parapet of the naval college, is found to be perfectly satisfactory as regards both steadiness and visibility. the observations of a low star for zero of azimuth have been omitted since the beginning of 1881; the mark, in combination with a high star, appearing to give all that is necessary for this purpose.--all the instruments have suffered from the congealing of the oil during the severe weather of the past winter, and very thorough cleaning of all the moving parts has been necessary.--the solar eclipse of 1880, dec. 31, was well observed. the first contact was observed by four observers and the last contact by two. the computations for the observations have been exceptionally heavy, from the circumstance that the sun was very low (86â° 14' z.d. at the last observation) and that it has therefore been necessary to compute the refraction with great accuracy, involving the calculation of the zenith distance for every observation. and besides this, eighty-six separate computations of the tabular r.a. and n.p.d. of cusps have been required.--amongst other interesting spectroscopic observations of the sun, a remarkable spectrum of a sun-spot shewing 17 strong black lines or bands, each as broad as b_1, in the solar spectrum, was observed on 1880, nov. 27 and 29. these bands to which there is nothing corresponding in the solar spectrum (except some very faint lines) have also been subsequently remarked in the spectrum of several spots.--the police ship 'royalist' (which was injured by a collision in 1879 and had been laid up in dock) has not been again moored in the river, and the series of observations of the temperature of the thames is thus terminated. --part of the month of january 1881 was, as regards cold, especially severe. the mean temperature of the period january 12 to 26 (15 days) was only 24.2â°, or 14.7â° below the average; the temperature fell below 20â° on 10 days, and rose above the freezing point only on 3 days. the highest temperature in this period was 35.3â°, the lowest 12.7â°. on january 17th (while staying at playford) my son hubert and i noticed an almost imperceptible movement in the upper clouds from the south-east. on that night began the terrible easterly gale, accompanied with much snow, which lasted to the night of the 18th. the limiting pressure of 50 lbs. on the square foot of osler's anemometer was twice exceeded during this storm.--with respect to the diurnal inequalities of magnetic horizontal force: assuming it to be certain that they originate from the sun's power, not immediately, but mediately through his action on the earth, it appears to me (as i suggested long ago) that they are the effects of the attraction of the red end or north end of the needle by the heated portions of our globe, especially by the heated sea, whose effect appears to predominate greatly over that of the land. i do not say that everything is thus made perfectly clear, but i think that the leading phenomena may be thus explained. and this is almost necessarily the way of beginning a science.--in the first few years after the strict and systematic examination of competitive chronometers, beginning with 1856, the accuracy of chronometers was greatly increased. for many years past it has been nearly stationary. i interpret this as shewing that the effects of bad workmanship are almost eliminated, and that future improvement must be sought in change of some points of construction.--referring to the transit of venus in 1874, the printing of all sections of the observations, with specimens of the printed forms employed, and remarks on the photographic operations, is very nearly completed. an introduction is begun in manuscript. i am in correspondence with the commission which is entrusted with the arrangements for observation of the transit of 1882.--the numerical lunar theory has been much interrupted by the pressure of the transit of venus work and other business."--in his report to the board of visitors (his 46th and last), airy remarks that it would be a fitting opportunity for the expression of his views on the general objects of the observatory, and on the duties which they impose on all who are actively concerned in its conduct. and this he proceeds to do in very considerable detail.--on may 5th he wrote to lord northbrook (first lord of the admiralty) and to mr gladstone to resign his post of astronomer royal. from time to time he was engaged on the subject of a house for his future residence, and finally took a lease of the white house at the top of croom's hill, just outside one of the gates of greenwich park. on the 15th of august he formally resigned his office to mr w.h.m. christie, who had been appointed to succeed him as astronomer royal, and removed to the white house on the next day, august 16th. his holiday movements in the portion of the year up to august 16th consisted in his winter visit to playford, from which he returned on jan. 24th: and a subsequent visit to playford from june 7th to 18th. * * * * * the following correspondence relating to airy's retirement from office testifies in a remarkable manner to the estimation in which his services were held, and to the good feeling which subsisted between him and his official superiors. 10, downing street, whitehall, _june 6, 1881_. dear sir george airy, i cannot receive the announcement of your resignation, which you have just conveyed to me, without expressing my strong sense of the distinction you have conferred upon the office of astronomer royal, and of the difficulty of supplying your place with a person of equal eminence. let me add the expression of my best wishes for the full enjoyment of your retirement from responsibility. i remain, dear sir george airy, faithfully yours, w.e. gladstone. * * * * * admiralty, _june 10th, 1881_. sir, i am commanded by my lords commissioners of the admiralty to acknowledge the receipt of your letter of the 4th instant, intimating your desire to retire on the 15th august next from the office of astronomer royal. 2. in reply i am to acquaint you that your wishes in this matter have been communicated to the prime minister, and that the further necessary official intimation will in due course be made to the treasury. 3. at the same time i am instructed by their lordships to convey to you the expression of their high appreciation of the remarkably able and gifted manner, combined with unwearied diligence and devotion to the public service (especially as regards the department of the state over which they preside), in which you have performed the duties of astronomer royal throughout the long period of forty-five years. 4. i am further to add that their lordships cannot allow the present opportunity to pass without giving expression to their sense of the loss which the public service must sustain by your retirement, and to the hope that you may long enjoy the rest to which you are so justly entitled. i am, sir, your obedient servant, robert hall. _sir g. b. airy, k.c.b. &c., &c., royal observatory, greenwich._ * * * * * admiralty, _28th june, 1881_. sir, my lords commissioners of the admiralty have much pleasure in transmitting copy of a resolution passed by the board of visitors of the royal observatory on the 4th june last, bearing testimony to the valuable services you have rendered to astronomy, to navigation, and the allied sciences throughout the long period during which you have presided over the royal observatory. i am, sir, your obedient servant, robert hall. _sir george biddell airy, k.c.b. &c., &c., &c., royal observatory, greenwich._ "the astronomer royal (sir george b. airy) having announced his intention of shortly retiring from his position at the royal observatory, the following resolution proposed by professor j. c. adams, and seconded by professor g. g. stokes, was then unanimously adopted and ordered to be recorded in the minutes of the proceedings. "the board having heard from the astronomer royal that he proposes to terminate his connection with the observatory on the 15th of august next, desire to record in the most emphatic manner their sense of the eminent services which he has rendered to astronomy, to navigation and the allied sciences, throughout the long period of 45 years during which he has presided over the royal observatory. "they consider that during that time he has not only maintained but has greatly extended the ancient reputation of the institution, and they believe that the astronomical and other work which has been carried on in it under his direction will form an enduring monument of his scientific insight and his powers of organization. "among his many services to science, the following are a few which they desire especially to commemorate: _(a)_ "the complete re-organization of the equipment of the observatory. _(b)_ "the designing of instruments of exceptional stability and delicacy suitable for the increased accuracy of observation demanded by the advance of astronomy. _(c)_ "the extension of the means of making observations of the moon in such portions of her orbit as are not accessible to the transit circle. _(d)_ "the investigation of the effect of the iron of ships upon compasses and the correction of the errors thence arising. _(e)_ "the establishment at the observatory and elsewhere of a system of time signals since extensively developed by the government. "the board feel it their duty to add that sir george airy has at all times devoted himself in the most unsparing manner to the business of the observatory, and has watched over its interests with an assiduity inspired by the strongest personal attachment to the institution. he has availed himself zealously of every scientific discovery and invention which was in his judgment capable of adaptation to the work of the observatory; and the long series of his annual reports to the board of visitors furnish abundant evidence, if such were needed, of the soundness of his judgment in the appreciation of suggested changes, and of his readiness to introduce improvements when the proper time arrived. while maintaining the most remarkable punctuality in the reduction and publication of the observations made under his own superintendance, he had reduced, collected, and thus rendered available for use by astronomers, the lunar and planetary observations of his predecessors. nor can it be forgotten that, notwithstanding his absorbing occupations, his advice and assistance have always been at the disposal of astronomers for any work of importance. "to refer in detail to his labours in departments of science not directly connected with the royal observatory may seem to lie beyond the province of the board. but it cannot be improper to state that its members are not unacquainted with the high estimation in which his contributions to the theory of tides, to the undulatory theory of light, and to various abstract branches of mathematics are held by men of science throughout the world. "in conclusion the board would express their earnest hope, that in his retirement sir george airy may enjoy health and strength and that leisure for which he has often expressed a desire to enable him not only to complete the numerical lunar theory on which he has been engaged for some years past, but also to advance astronomical science in other directions." * * * * * admiralty, _27th october, 1881_. sir, i am commanded by my lords commissioners of the admiralty to transmit to you, herewith, a copy of a treasury minute, awarding you a special pension of _â£1100_ a year, in consideration of your long and brilliant services as astronomer royal. i am, sir, your obedient servant, robert hall. _sir g.b. airy, k.c.b., f.r.s., &c., &c. the white house, croom's hill, greenwich._ copy of treasury minute, dated 10th october, 1881: my lords have before them a statement of the services of sir george biddell airy, k.c.b., f.r.s., who has resigned the appointment of astronomer royal on the ground of age. sir george airy has held his office since the year 1835, and has also, during that period, undertaken various laborious works, demanding scientific qualifications of the highest order, and not always such as could strictly be said to be included among the duties of his office. the salary of sir g. airy as astronomer royal is _â£1200_ a year, in addition to which he enjoys an official residence rent free, and, under ordinary circumstances he would be entitled to a pension equal to two-thirds of his salary and emoluments. my lords, however, in order to mark their strong sense of the distinction which, during a long and brilliant career sir george airy has conferred upon his office, and of the great services which, in connection with, as well as in the discharge of, his duties, he has rendered to the crown and the public, decide to deal with his case under the ixth section of the superannuation act, 1859, which empowers them to grant a special pension for special services. accordingly my lords are pleased to award to sir george biddell airy, k.c.b., f.r.s., a special retired allowance of _â£1100_ per annum. * * * * * the white house, croom's hill, greenwich, _1881, october 29_. sir, i have the honour to acknowledge your letter of october 27, transmitting to me, by instruction of the lords commissioners of admiralty, copy of a treasury minute dated 1881 october 10, in which the lords commissioners of her majesty's treasury are pleased to award to me an annual retired allowance of _â£1100_ per annum. acknowledging the very liberal award of the lords commissioners of treasury, and the honourable and acceptable terms in which it is announced, i take leave at the same time to offer to their lordships of the admiralty my recognition of their lordships' kindness and courtesy in thus handing to me copy of the treasury minute. i have the honour to be, sir, your very obedient servant, g.b. airy. _the secretary of the admiralty,_ * * * * * from the assistants of the royal observatory, with whom he was in daily communication, whose faithful and laborious services he had so often thankfully recognized in his annual reports to the board of visitors, and to whom so much of the credit and success of the observatory was due, he received the following address: royal observatory, greenwich, _1881, august 11_. dear sir, we cannot allow the official relation which has so long existed between yourself and us to terminate without expressing to you our sense of the admirable manner in which you have, in our opinion, upheld the dignity of the office of astronomer royal during the many years that you have occupied that important post. your long continued and varied scientific work has received such universal recognition from astronomers in all lands, that it is unnecessary for us to do more than assure you how heartily we join in their appreciation of your labours. we may however add that our position has given us opportunities of seeing that which others cannot equally well know, the untiring energy and great industry which have been therein displayed throughout a long and laborious career, an energy which leads you in retirement, and at fourscore years of age, to contemplate further scientific work. we would ask you to carry with you into private life the best wishes of each one of us for your future happiness, and that of your family, expressing the hope that the days of retirement may not be few, and assuring you that your name will long live in our remembrance. we are, dear sir, yours very faithfully, w.h.m. christie, edwin dunkin, william ellis, george strickland criswick, w. c. nash, a.m.w. downing, edward w. maunder, w.g. thackeray, thomas lewis. _sir g.b. airy, k.c.b., &c., &c., astronomer royal._ * * * * * royal observatory, greenwich, _1881, august 13_. my dear mr christie, and gentlemen of the royal observatory, with very great pleasure i have received your letter of august 11. i thank you much for your recognition of the general success of the observatory, and of a portion of its conduct which--as you remark--can scarcely be known except to those who are every day engaged in it: but i thank you still more for the kind tone of your letter, which seems to shew that the terms on which we have met are such as leaves, after so many years' intercourse, no shadow of complaint on any side. reciprocating your wishes for a happy life, and in your case a progressive and successful one, i am, my dear mr christie and gentlemen, yours faithfully, g.b. airy. * * * * * throughout his tenure of office airy had cultivated and maintained the most friendly relations with foreign astronomers, to the great advantage of the observatory. probably all of them, at one time or another, had visited greenwich, and to most of them he was well known. on his retirement from office he received an illuminated address from his old friend otto struve and the staff of the pulkowa observatory, an illuminated address from the vorstand of the astronomische gesellschaft at berlin signed by dr auwers and the secretaries, a complimentary letter from the academy of sciences at amsterdam, and friendly letters of sympathy from dr gould, prof. newcombe, dr listing, and from many other scientific friends and societies. his replies to the russian and german addresses were as follows: royal observatory, greenwich, _1881, august 5_. my dear sir, i received, with feelings which i will not attempt to describe, the address of yourself and the astronomers of pulkowa generally, on the occasion of my retirement from the office of astronomer royal. i can scarcely credit myself with possessing all the varied claims to your scientific regard which you detail. i must be permitted to attribute many of them to the long and warm friendship which has subsisted so long between the directors of the pulkowa observatory and myself, and which has influenced the feelings of the whole body of astronomers attached to that institution. on one point, however, i willingly accept your favourable expressions--i have not been sparing of my personal labour--and to this i must attribute partial success on some of the subjects to which you allude. in glancing over the marginal list of scientific pursuits, i remark with pleasure the reference to _optics_. i still recur with delight to the undulatory theory, once the branch of science on which i was best known to the world, and which by calculations, writings, and lectures, i supported against the laplacian school. but the close of your remarks touches me much more--the association of the name of w. struve and my own. i respected deeply the whole character of your father, and i believe that he had confidence in me. from our first meeting in 1830 (on a commission for improvement of the nautical almanac) i never ceased to regard him as superior to others. i may be permitted to add that the delivery of his authority to the hands of his son has not weakened the connection of myself with the observatory of poulkova. acknowledging gratefully your kindness, and that of all the astronomers of the observatory of poulkova, and requesting you to convey to them this expression, i am, my dear sir, yours most truly, g.b. airy. _to m. otto von struve, director of the observatory of poulkova and the astronomers of that observatory._ * * * * * royal observatory, greenwich, _1881, august 3_. my dear sir, with very great pleasure i received the address of the astronomische gesellschaft on occasion of my intended resignation of the office of astronomer royal: dated july 27, and signed by yourself as president and messrs schoenfeld and winnecke as secretaries of the astronomische gesellschaft. i thank you much for the delicacy of your arrangement for the transmission of this document by the hands of our friend dr huggins. and i think you will be gratified to learn that it arrived at a moment when i was surrounded by my whole family assembled at my _jour-de-fãªte_, and that it added greatly to the happiness of the party. i may perhaps permit myself to accept your kind recognition of my devotion of time and thought to the interests of my science and my office. it is full reward to me that they are so recognized. as to the success or utility of these efforts, without presuming, myself, to form an opinion, i acknowledge that the connection made by the astronomische gesellschaft, between my name and the advance of modern astronomy, is most flattering, and will always be remembered by me with pride. it is true, as is suggested in your address, that one motive for my resignation of office was the desire to find myself more free for the prosecution of further astronomical investigations. should my health remain unbroken, i hope to enter shortly upon this undertaking. again acknowledging the kindness of yourself and the vorstand of the astronomische gesellschaft, and offering my best wishes for the continued success of that honourable institution, i am, my dear sir, yours very truly, g.b. airy. _to dr aimers and the vorstand of the astronomische gesellschaft._ chapter x. at the white house, greenwich. from his resignation of office on august 15th, 1881, to his death on january 2nd, 1892. history of his life after his resignation of office. on the 16th of august 1881 airy left the observatory which had been his residence for nearly 46 years, and removed to the white house. whatever his feelings may have been at the severing of his old associations he carefully kept them to himself, and entered upon his new life with the cheerful composure and steadiness of temper which he possessed in a remarkable degree. he was now more than 80 years old, and the cares of office had begun to weigh heavily upon him: the long-continued drag of the transit of venus work had wearied him, and he was anxious to carry on and if possible complete his numerical lunar theory, the great work which for some years had occupied much of his time and attention. his mental powers were still vigorous, and his energy but little impaired: his strong constitution, his regular habits of life, the systematic relief which he obtained by short holiday expeditions whenever he found himself worn with work, and his keen interest in history, poetry, classics, antiquities, engineering, and other subjects not immediately connected with his profession, had combined to produce this result. and in leaving office, he had no idea of leaving off work; his resignation of office merely meant for him a change of work. it is needless to say that his interest in the welfare and progress of the observatory was as keen as ever; his advice was always at the service of his successor, and his appointment as visitor a year or two after his resignation gave him an official position with regard to the observatory which he much valued. the white house, which was to be his home for the rest of his life, is just outside one of the upper gates of the park, and about a quarter of a mile from the observatory. here he resided with his two unmarried daughters. the house suited him well and he was very comfortable there: he preferred to live in the neighbourhood with which he was so familiar and in which he was so well known, rather than to remove to a distance. his daily habits of life were but little altered: he worked steadily as formerly, took his daily walk on blackheath, made frequent visits to playford, and occasional expeditions to the cumberland lakes and elsewhere. the work to which he chiefly devoted himself in his retirement was the completion of his numerical lunar theory. this was a vast work, involving the subtlest considerations of principle, very long and elaborate mathematical investigations of a high order, and an enormous amount of arithmetical computation. the issue of it was unfortunate: he concluded that there was an error in some of the early work, which vitiated the results obtained: and although the whole process was published, and was left in such a state that it would be a comparatively simple task for a future astronomer to correct and complete it, yet it was not permitted to the original author of it to do this. to avoid the necessity of frequent reference to this work in the history of airy's remaining years, it will be convenient to summarize it here. it was commenced in 1872: "on feb. 23rd in this year i first (privately) formed the notion of preparing a numerical lunar theory by substituting delaunay's numbers in the proper equations and seeing what would come of it." from this time forward till his power to continue it absolutely failed, he pursued the subject with his usual tenacity of purpose. during his tenure of office every available opportunity was seized for making progress with his lunar theory, and in every report to the visitors a careful statement was inserted of the state in which it then stood. and, after his resignation of office, it formed the bulk of his occupation. in 1873 the theory was formed, and by 1874 it was so far advanced that he published in the monthly notices of the royal astronomical society a statement of the fundamental points of the theory. in 1875, the theory having advanced to a stage where extensive arithmetical computation was required, he obtained a small grant from the government in aid of the expense of the work, and other grants were made in subsequent years. by 1878 the calculations were so far advanced that an opinion could be formed as to the probable accuracy of the theory, and the following remark is made: "a cursory collation of the terms relating to the areas (in the ecliptic) led me to suppose that there might be some error in the computations of the annual equation and related terms;" but no error could be discovered and the work proceeded. the complex character of the theory, and the extreme care required in the mathematical processes, are well illustrated by the following statement, which occurs in the report of 1879, "an important error in the theoretical formulae for variations of radius vector, longitude, and latitude, was discovered; some calculations depending on them are cancelled." in 1880 and 1881 the work was continued, but was "sadly interrupted by the pressure of the transit of venus work and other business." after his resignation of the office of astronomer royal he had no further public assistance, and did much of the computations himself, but a sum of _â£100_ was contributed by mr de la rue in furtherance of the work, and this sum was spent on computers. in his retirement the work made good progress, and on dec. 31st, 1882, he made the following note: "i finished and put in general order the final tables of equations of variations. this is a definite point in the lunar theory.... i hope shortly to take up severely the numerical operations of the lunar theory from the very beginning." the work was continued steadily through 1883, and on mar. 24th, 1884, he made application through the board of visitors to the admiralty to print the work: after the usual enquiries as to the expense this was acceded to, and copy was sent to the printers as soon as it was ready. the first printed proofs were received on feb. 5th, 1885, and the whole book was printed by the end of 1886. from the frequent references in his journal to errors discovered and corrected during the progress of these calculations, it would seem likely that his powers were not what they had been, and that there was a probability that some important errors might escape correction. he was far too honest to blind himself to this possibility, and in the preface to his numerical lunar theory he says thus: "i have explained above that the principle of operations was, to arrange the fundamental mechanical equations in a form suited for the investigations of lunar theory; to substitute in the terms of these equations the numerical values furnished by delaunay's great work; and to examine whether the equations are thereby satisfied. with painful alarm, i find that they are not satisfied; and that the discordance, or failure of satisfying the equations, is large. the critical trial depends on the great mass of computations in section ii. these have been made in duplicate, with all the care for accuracy that anxiety could supply. still i cannot but fear that the error which is the source of discordance must be on my part. i cannot conjecture whether i may be able to examine sufficiently into this matter." he resolutely took in hand the revision of his work, and continued it till october 1888. but it is clear from the entries in his journal that his powers were now unequal to the task, and although from time to time he suspected that he had discovered errors, yet it does not appear that he determined anything with certainty. he never doubted that there were important errors in the work, and later on he left the following private note on the subject: numerical lunar theory. _1890, sept. 29_. i had made considerable advance (under official difficulties) in calculations on my favourite numerical lunar theory, when i discovered that, under the heavy pressure of unusual matters (two transits of venus and some eclipses) i had committed a grievous error in the first stage of giving numerical value to my theory. my spirit in the work was broken, and i have never heartily proceeded with it since. g.b. airy. probably the error referred to here is the suspected error mentioned above in his report of 1878, as to which he subsequently became more certain. whatever may be the imperfections of the numerical lunar theory, it is a wonderful work to have been turned out by a man 85 years old. in its idea and inception it embodies the experience of a long life actively spent in practical science. and it may be that it will yet fulfil the objects of its author, and that some younger astronomer may take it up, correct its errors (wherever they may be), and fit it for practical use. and then the labour bestowed upon it will not have been in vain. subject always to the absorbing occupations of the lunar theory he amused himself with reading his favourite subjects of history and antiquities. his movements during the remainder of the year 1881 were as follows: in september he paid a two days' visit to lady herschel at hawkhurst. from oct. 4th to 17th he was at the cumberland lakes and engaged in expeditions in the neighbourhood. from nov. 5th to 8th he was at cambridge, inspecting prof. stuart's workshops, and other scientific institutions. on dec. 13th he went to playford.--amongst miscellaneous matters: in november he wrote to mr rothery on the loss of the 'teuton' at some length, with suggestions for the safer construction of such vessels.--in october he was asked for suggestions regarding the establishment of a "standard time" applicable to the railway traffic in the united states: he replied as follows: _1881, oct. 31_. sir, i have to acknowledge your letter of october 17, introducing to my notice the difficulty which appears to be arising in america regarding a "standard time," for extensive use throughout n. america "applicable to railway traffic only." the subject, as including considerations of convenience in all the matters to which it applies, is one of difficulties probably insuperable. the certainty, however, that objections may be raised to every scheme, renders me less timid in offering my own remarks; which are much at your service. i first comment upon your expression of "standard time... applicable to railway traffic only." but do you mean this as affecting the transactions between one railway and another railway, or as affecting each railway and the local interests (temporal and others) of the towns which it touches? the difference is so great that i should be disposed to adopt it as marking very strongly the difference to be made between the practices of railways among themselves and the practices of railways towards the public; and will base a system on that difference. as regards the practices of railways among themselves: if the various railways of america are joined and inosculated as they are in england, it appears to me indispensable that they have one common standard _among themselves_: say washington observatory time. but this is only needed for the office-transactions between the railways; it may be kept perfectly private; never communicated to the public at all. and i should recommend this as the first step. there will then be no difficulty in deducing, from these private washington times, the accurate local times at those stations (whose longitude is supposed to be fairly well known, as a sailor with a sextant can determine one in a few hours) which the railway authorities may deem worthy of that honour; generally the termini of railways. thus we shall have a series of bases of local time, of authoritative character, through the country. of such bases _we_ have two, greenwich and dublin: and they are separated by a sea-voyage. in the u.s. of america there must be a greater number, and probably not so well separated. still it is indispensable to adopt such a system of local centers. no people in this world can be induced to use a reckoning which does not depend clearly upon the sun. in all civilized countries it depends (approximately) on the sun's meridian passage. even the sailor on mid-ocean refers to that phenomenon. and the solar passage, with reasonable allowance, 20m. or 30m. one way or another, must be recognized in all time-arrangements as giving the fundamental time. the only practical way of doing this is, to adopt for a whole region the fundamental time of a center of that region. and to this fundamental time, the local time of the railway, as now entering into all the concerns of life, must be adapted. a solicitor has an appointment to meet a client by railway; a physician to a consultation. how is this to be kept if the railway uses one time and every other act of life another? there is one chain of circumstances which is almost peculiar--that of the line from new york to san francisco. here i would have two clocks at every station: those on the north side all shewing san francisco time, and those on the south all shewing new york time. every traveller's watch would then be available to the end of his journey. a system, fundamentally such as i have sketched, would give little trouble, and may i think be adopted with advantage. i am, sir, your faithful servant, g.b. airy. _mr edward barrington._ 1882 he returned from playford on jan. 17: his other movements during the year were as follows: from apr. 27th to may 11th he was at playford; and again from august 1st to 24th. from oct. 9th to nov. 1st he was travelling with his two unmarried daughters in the lake district of cumberland: the journey was by furness and coniston to portinscale near keswick; on oct. 13th he fell and sprained his ankle, and his excursions for the rest of the time were mainly conducted by driving. shortly after his return, on nov. 11th, while walking alone on blackheath, he was seized with a violent attack of illness, and lay helpless for some time before he was found and brought home: he seems however to have recovered to a great extent in the course of a day or two, and continued his lunar theory and other work as before. on june 22nd he made the following sad note, "this morning, died after a most painful illness my much-loved daughter-in-law, anna airy, daughter of professor listing of gã¶ttingen, wife of my eldest son wilfrid." in february he wrote out his reminiscences of the village of playford during his boyhood. in june he was much disturbed in mind on hearing of some important alterations made by the astronomer royal in the collimators of the transit circle, and some correspondence ensued on the subject.--during the year he had much correspondence on the subject of the subsidences on blackheath. the following letter was written in reply to a gentleman who had asked whether it could be ascertained by calculation how long it is since the glacial period existed: _1882, july 4_. sir, i should have much pleasure in fully answering your questions of july 3 if i were able to do so: but the subject really is very obscure. (1) though it is recognized that the glacial period (or periods) is late, i do not think that any one has ventured to fix upon a rude number of years since elapsed. (2) we have no reason to think that the mean distance of the earth from the sun has sensibly altered. there have been changes in the eccentricity of the orbit (making the earth's distance from the sun less in one month and greater in the opposite month), but i do not perceive that this would explain glaciers. (3) i consider it to be certain that the whole surface of the earth, at a very distant period, was very hot, that it has cooled gradually, and (theoretically and imperceptibly) is cooling still. the glaciers must be later than these hot times, and later than our last consolidated strata: but this is nearly all that i can say. i am, sir, your obedient servant, g.b. airy. _james alston, esq._ 1883 from may 2nd to 29th he was at playford. from july 10th to 20th he was travelling in south wales with his daughters.--from oct. 10th to nov. 10th he was at playford.--between nov. 20th of this year and jan. 4th of the year 1884, he sat several times to mr john collier for his portrait: the picture was exhibited in the academy of 1884; it is a most successful and excellent likeness. throughout the year he was very busy with the numerical lunar theory.--in march he was officially asked to accept the office of visitor of the royal observatory, which he accepted, and in this capacity attended at the annual visitation on june 2nd, and addressed a memorandum to the visitors on the progress of his lunar theory.--on march 12th he published in several newspapers a statement in opposition to the proposed braithwaite and buttermere railway, which he considered would be injurious to the lake district, in which he took so deep an interest.--in may he communicated to "the observatory" a statement of his objections to a theory advanced by mr stone (then president of the royal astronomical society) to account for the recognized inequality in the mean motion of the moon. this theory, on a subject to which airy had given his incessant attention for so many years, would naturally receive his careful attention and criticism, and it attracted much general notice at the time.--in december he wrote to the secretary of the royal astronomical society his opinion as to the award of the medal of the society. in this letter he stated the principles which guided him as follows: "i have always maintained that the award of the medal ought to be guided mainly by the originality of communications: that one advance in a new direction ought in our decision to outweigh any mass of work in a routine already established: and that, in any case, scientific utility as distinguished from mere elegance is indispensable."--in july lieut. pinheiro of the brazilian navy called with an autograph letter of introduction from the emperor of brazil. the lieutenant desired to make himself acquainted with the english system of lighthouses and meteorology, and airy took much trouble in providing him with introductions through which he received every facility for the thorough accomplishment of his object.--on oct. 8th he forwarded to prof. cayley proofs of euclid's propositions i. 47 and iii. 35 with the following remarks: "i place on the other side the propositions which may be substituted (with knowledge of euclid's vi. book) for the two celebrated propositions of the geometrical books. they leave on my mind no doubt whatever that they were invented as proofs by ratios, and that they were then violently expanded into cumbrous geometrical proofs."--on june 28th he declined to sign a memorial asking for the interment of mr spottiswoode in westminster abbey, stating as his reason, "i take it, that interment possessing such a public character is a public recognition of benefits, political, literary, or philosophical, whose effects will be great and durable. now i doubt whether it can be stated that mr spottiswoode had conferred such benefits on society. "but he adds at length his cordial recognition of mr spottiswoode's scientific services.--throughout his life airy was a regular attendant at church, and took much interest in the conduct of the church services. in october of this year he wrote a long letter to the vicar of greenwich on various points, in which occurs the following paragraph: "but there is one matter in the present form of the church service, on which my feeling is very strong, namely the (so-called, i believe) choral service, in the confession, the prayer, and the creed. i have long listened with veneration to our noble liturgy, and i have always been struck with the deep personally religious feeling which pervades it, especially those parts of it which are for 'the people.' and an earnest priest, earnestly pressing these parts by his vocal example on the notice of the people, can scarcely fail to excite a corresponding earnestness in them. all this is totally lost in the choral system. for a venerable persuasion there is substituted a rude irreverential confusion of voices; for an earnest acceptance of the form offered by the priest there is substituted--in my feeling at least--a weary waiting for the end of an unmeaning form." he also objected much to singing the responses to the commandments. 1884 from apr. 29th to may 30th he was at playford, concluding his journal there with the note "so ends a pleasant vacation."--on june 11th he went to cambridge and attended the trinity college commemoration service, and dined in hall.--from aug. 14th to sept. 11th he was at playford.--on sept. 26th he made an expedition to guildford and farnham.--during this year he was closely engaged on the numerical lunar theory, and for relaxation was reading theology and sundry books of the old testament. on june 7th he attended at the visitation of the royal observatory.--in a letter written in april to lt.-col. marindin, r.a., on the subject of wind pressure there occurs the following remark: "when the heavy gusts come on, the wind is blowing in directions changing rapidly, but limited in extent. my conclusion is that in arches of small extent (as in the tay bridge) every thing must be calculated for full pressure; but in arches of large extent (as in the forth bridge) every thing may be calculated for small pressure. and for a suspension bridge the pressure is far less dangerous than for a stiff arch."--in january he had some correspondence with professor tyndall on the theory of the "white rainbow," and stated that he thoroughly agreed with dr young's explanation of this phaenomenon. --the following is extracted from a letter on may 1st to his old friend otto struve: "i received from you about 3 or 4 weeks past a sign of your friendly remembrance, a copy of your paper on the annual parallax of aldebaran. it pleased me much. especially i was delighted with your noble retention of the one equation whose result differed so sensibly from that of the other equations. it is quite possible, even probable, that the mean result is improved by it. i have known such instances. the first, which attracted much attention, was capt. kater's attempt to establish a scale of longitude in england by reciprocal observations of azimuth between beachy head and dunnose. the result was evidently erroneous. but colonel colby, on examination of the original papers, found that some observations had been omitted, as suspicious; and that when these were included the mean agreed well with the scale of observation inferred from other methods."--in a letter to the rev. r.c.m. rouse, acknowledging the receipt of a geometrical book, there occurs the following paragraph: "i do not value euclid's elements as a super-excellent book of instruction--though some important points are better presented in it than in any other book of geometrical instruction that i have seen. but i value it as a book of strong and distinct reasoning, and of orderly succession of reasonings. i do not think that there is any book in the world which presents so distinctly the 'because...... therefore.......' and this is invaluable for the mental education of youth."--in may he was in correspondence with professor balfour stewart regarding a projected movement in terrestrial magnetism to be submitted to the british association. airy cordially approved of this movement, and supported it to the best of his ability, stating that in his opinion what was mainly wanted was the collation of existing records.--in january and february he was much pressed by prof. pritchard of oxford to give his opinion as to the incorrectness of statements made by dr kinns in his lectures on the scientific accuracy of the bible. airy refused absolutely to take part in the controversy, but he could not escape from the correspondence which the matter involved: and this led up to other points connected with the early history of the israelites, a subject in which he took much interest. 1885 from may 4th to june 3rd he was at playford.--from july 2nd to 22nd he was in the lake district. the journey was by windermere to kentmere, where he made enquiries concerning the airy family, as it had been concluded with much probability from investigations made by his nephew, the rev. basil r. airy, that the family was settled there at a very early date. some persons of the name of airy were still living there. he then went on by coniston and grasmere to portinscale, and spent the rest of his time in expeditions amongst the hills and visits to friends.--on july 28th he went to woodbridge in suffolk and distributed the prizes to the boys of the grammar school there.--from oct. 9th to nov. 12th he was again at playford.--throughout the year he was busily engaged on the numerical lunar theory, and found but little time for miscellaneous reading. of printed papers by airy in this year the most important was one on the "results deduced from the measures of terrestrial magnetic force in the horizontal plane," &c. this was a long paper, communicated to the royal society, and published in the phil. trans., and was the last scientific paper of any importance (except the volume of the numerical lunar theory) in the long list of "papers by g.b. airy." the preparation of this paper took much time.--of miscellaneous matters: in may a committee of the royal society had been appointed to advise the india office as to the publication of col. j. herschel's pendulum observations in india; and airy was asked to assist the committee with his advice. he gave very careful and anxious consideration to the subject, and it occupied much time.--in the early part of the year he was asked by sir william thomson to assist him with an affidavit in a lawsuit concerning an alleged infringement of one of his patents for the improvement of the compass. airy declined to make an affidavit or to take sides in the dispute, but he wrote a letter from which the following is extracted: "i cannot have the least difficulty in expressing my opinion that you have made a great advance in the application of my method of correcting the compass in iron ships, by your introduction of the use of short needles for the compass-cards. in my original investigations, when the whole subject was in darkness, i could only use existing means for experiment, namely the long-needle compasses then existing. but when i applied mechanical theory to explanation of the results, i felt grievously the deficiency of a theory and the construction which it suggested (necessarily founded on assumption that the proportion of the needle-length to the other elements of measure is small) when the length of the needles was really so great. i should possibly have used some construction like yours, but the government had not then a single iron vessel, and did not seem disposed to urge the enquiry. you, under happier auspices, have successfully carried it out, and, i fully believe, with much advantage to the science."--he wrote a paper for the athenaeum and had various correspondence on the subject of the badbury rings in dorsetshire, which he (and others) considered as identical with the "mons badonicus" of gildas, the site of an ancient british battle.--in february he was in correspondence with the astronomer royal on uniform time reckoning, and on considerations relating to it.--on june 6th he attended the annual visitation of the observatory, and brought before the board his investigations of the diurnal magnetic inequalities, and the revises of his lunar theory. 1886 from june 8th to july 17th he was at playford.--and again at playford from oct. 5th to nov. 8th.--on march 27th he had an attack of gout in his right foot, which continued through april and into may, causing him much inconvenience.--he was busy with the numerical lunar theory up to sept. 25th, when he was reading the last proof-sheet received from the printers: during this period his powers were evidently failing, and there are frequent references to errors discovered and corrected, and to uncertainties connected with points of the theory. but his great work on the numerical lunar theory was printed in this year: and there can be no doubt that he experienced a great feeling of relief when this was accomplished.--he was in correspondence with prof. adams as to the effect of his reduction of the coefficient of lunar acceleration on the calculation of the ancient historical eclipses.--he compiled a paper "on the establishment of the roman dominion in england," which was printed in 1887.--he wrote a notice concerning events in the life of mr john jackson of rosthwaite near keswick, a well-known guide and much-respected authority on matters relating to the lake district.--he also wrote a short account of the connection of the history of mdlle de quã©roualle with that of the royal observatory at greenwich.--on june 4th he attended at the annual visitation of the observatory. 1887 on may 9th to 11th he made a short visit to eastbourne and the neighbourhood.--from june 8th to july 13th he was at playford.--from aug. 29th to sept. 5th he was travelling in dorsetshire and wiltshire: he went first to weymouth, a very favourite centre for excursions with him, and afterwards visited bridport and lyme regis: then by dorchester to blandford, and visited the hod hill, badbury rings, &c.: at wimborne he was much interested in the architecture of the church: lastly he visited salisbury, old sarum, stonehenge, &c., and returned to greenwich.--from oct. 11th to nov. 12th he was at playford.--during this year he partly occupied himself with arranging his papers and drawings, and with miscellaneous reading. but he could not withdraw his thoughts from his lunar theory, and he still continued to struggle with the difficulties of the subject, and was constantly scheming improvements. his private accounts also now gave him much trouble. throughout his life he had been accustomed to keep his accounts by double entry in very perfect order. but he now began to make mistakes and to grow confused, and this distressed him greatly. it never seemed to occur to him to abandon his elaborate system of accounts, and to content himself with simple entries of receipts and expenses. this would have been utterly opposed to his sense of order, which was now more than ever the ruling principle of his mind. and so he struggled with his accounts as he did with his lunar theory till his powers absolutely failed. in his journal for this year there are various entries of mental attacks of short duration and other ailments ascribable to his advanced age. the last printed "papers by g.b. airy" belong to this year. one was the paper before referred to "on the establishment of the roman dominion in england": another was on the solution of a certain equation: and there were early reminiscences of the cambridge tripos, &c.--in february he attended a little to a new edition of his ipswich lectures, but soon handed it over to mr h.h. turner of the royal observatory.--on may 23rd he was drawing up suggestions for the arrangement of the seckford school, &c., at woodbridge.--on june 4th he attended the visitation of the royal observatory, when a resolution was passed in favour of complete photography of the star-sky. 1888 from the 14th to 16th of may he made a short expedition to bournemouth, and stopped on the way home to visit winchester cathedral.--from june 27th to aug. 3rd he was at playford; and again from oct. 13th to nov. 10th.--during the first half of the year he continued his examination of his lunar theory, but gradually dropped it. there are several references in his journal to his feelings of pain and weakness, both mental and bodily: at the end of march he had an attack of gout in the fingers of his right hand. during the latter part of the year he was troubled with his private accounts, as before.--he does not appear to have been engaged on any miscellaneous matters calling for special notice in this year. but he kept up his astronomical correspondence--with lockyer on the meteorite system of planetary formation; with pritchard on the work of the oxford university observatory; with adams on his numerical lunar theory, &c., and with others.--on june 2nd he attended the visitation of the royal observatory.--he amused himself occasionally with reading his favourite subjects of history and antiquities, and with looking over some of his early investigations of scientific questions. 1889 on june 5th he made a one-day's excursion to colchester.--from july 2nd to 27th he was in the cumberland lake district, chiefly at portinscale near keswick. while staying at portinscale he was seized with a sudden giddiness and fell upon the floor: he afterwards wrote a curious account of the visions which oppressed his brain immediately after the accident. he returned by solihull, where his son osmund was residing.--from oct. 4th to nov. 8th he was at playford. while there he drew up a short statement of his general state of health, adverting particularly to the loss of strength in his legs and failure of his walking powers.--his health seems to have failed a good deal in this year: on feb. 4th he had an accidental fall, and there are several entries in his journal of mental attacks, pains in his limbs, affection of his eye-sight, &c.--in the early part of the year he was much engaged on the history of the airy family, particularly on that of his father.--in this year the white house was sold by auction by its owners, and airy purchased it on may 24th.--he was still in difficulties with his private accounts, but was making efforts to abandon his old and elaborate system.--for his amusement he was chiefly engaged on theological notes which he was compiling: and also on early optical investigations, &c. on june 1st he attended the visitation of the royal observatory, and moved a resolution that a committee be appointed to consider whether any reduction can be effected in the amount of matter printed in the volume of observations of the royal observatory. during his tenure of office he had on various occasions brought this subject before the board of visitors, and with his usual tenacity of purpose he now as visitor pressed it upon their notice.--in may he zealously joined with others in an application to get for dr huggins a pension on the civil list.--in january he prepared a short paper illustrated with diagrams to exhibit the interference of solar light, as used by him in his lectures at cambridge in 1836: but it does not appear to have been published.--in april he received a copy of a paper by mr rundell, referring to the complete adoption of his system of compass correction in iron ships, not only in the merchant service, but also in the navy. this was a matter of peculiar gratification to airy, who had always maintained that the method of tables of errors, which had been so persistently adhered to by the admiralty, was a mistake, and that sooner or later they would find it necessary to adopt his method of mechanical correction. the passage referred to is as follows: "the name of sir george airy, the father of the mechanical compensation of the compass in iron vessels, having just been mentioned, it may not be inappropriate to remind you that the present year is the fiftieth since sir george airy presented to the royal society his celebrated paper on this subject with the account of his experiments on the 'rainbow' and 'ironsides.' fifty years is a long period in one man's history, and sir george airy may well be proud in looking back over this period to see how complete has been the success of his compass investigation. his mode of compensation has been adopted by all the civilized world. sir william thomson, one of the latest and perhaps the most successful of modern compass adjusters, when he exhibited his apparatus in 1878 before a distinguished meeting in london, remarked that within the last ten years the application of sir george airy's method had become universal, not only in the merchant service, but in the navies of this and other countries, and added--the compass and the binnacles before you are designed to thoroughly carry out in practical navigation the astronomer royal's principles." 1890 from may 17th to 24th he was on an expedition to north wales, stopping at chester, conway, carnarvon, barmouth, and shrewsbury.--from june 18th to july 24th he was at playford; and again from oct. 11th to nov. 15th.--in this year his powers greatly failed, and he complained frequently of mental attacks, weakness of limbs, lassitude, and failure of sleep. he occupied himself as usual with his books, papers, and accounts; and read travels, biblical history, &c., but nothing very persistently. on june 7th he attended the visitation of the royal observatory.--from a letter addressed to him by mr j. hartnup, of liverpool observatory, it appears that there had grown up in the mercantile world an impression that very accurate chronometers were not needed for steam ships, because they were rarely running many days out of sight of land: and airy's opinion was requested on this matter. he replied as follows on mar. 3rd: "the question proposed in your letter is purely a practical one. (1) if a ship is _likely_ ever to be two days out of sight of land, i think that she ought to be furnished with two _good_ chronometers, properly tested. (2) for the proper testing of the rates of the chronometers, a rating of the chronometers for three or four days in a meridional observatory is necessary. a longer testing is desirable."--in march he was in correspondence, as one of the trustees of the sheepshanks fund, with the master of trinity relative to grants from the fund for cambridge observatory. 1891 from june 16th to july 15th he was at playford. and again from oct. 12th to dec. 2nd (his last visit). throughout the year his weakness, both of brain power and muscular power, had been gradually increasing, and during this stay at playford, on nov. 11th, he fell down in his bed-room (probably from failure of nerve action) and was much prostrated by the shock. for several days he remained in a semi-unconscious condition, and although he rallied, yet he continued very weak, and it was not until dec. 2nd that he could be removed to the white house. up to the time of his fall he had been able to take frequent drives and even short walks in the neighbourhood that he was so fond of, but he could take but little exercise afterwards, and on or about nov. 18th he made the following note: "the saddest expedition that i have ever made. we have not left home for several days." the rapid failure of his powers during this year is well exemplified by his handwriting in his journal entries, which, with occasional rallies, becomes broken and in places almost illegible. he makes frequent reference to his decline in strength and brain-power, and to his failing memory, but he continued his ordinary occupations, made frequent drives around blackheath, and amused himself with his family history researches, arrangement of papers, and miscellaneous reading: and he persisted to the last with his private accounts. his interest in matters around him was still keen. on june 13th he was driving along the greenwich marshes in order to track the course of the great sewer; and on august 5th he visited the crossness sewage works and took great interest in the details of the treatment of the sewage.--in march he contributed, with great satisfaction, to the fund for the portrait of his old friend sir g.g. stokes, with whom he had had so much scientific correspondence.--on july 25th an afternoon party was arranged to celebrate the 90th anniversary of his birthday (the actual anniversary was on july 27th). none of his early friends were there: he had survived them all. but invitations were sent to all his scientific and private friends who could be expected to come, and a large party assembled. the afternoon was very fine, and he sat in the garden and received his friends (many of whom had come from long distances) in good strength and spirits. it was a most successful gathering and was not without its meaning; for it was felt that, under the circumstances of his failing powers, it was in all probability a final leave-taking.--on july 27th he went down to the greenwich parish church at 9 p.m., to be present at the illumination of the church clock face for the first time--a matter of local interest which had necessitated a good deal of time and money. on this occasion at the request of the company assembled in and around the vestry he spoke for about a quarter of an hour on time--the value of accurate time, the dissemination of greenwich time throughout the country by time-signals from the observatory, and the exhibition of it by time-balls, &c., &c.,--the subject to which so large a part of his life had been devoted. it was a pleasant and able speech and gave great satisfaction to the parishioners, amongst whom he had lived for so many years.--he received two illuminated addresses--one from the astronomer royal and staff of the royal observatory; the other from the vorstand of the astronomische gesellschaft at berlin--and various private letters of congratulation. the address from the staff of the observatory was worded thus: "we, the present members of the staff of the royal observatory, greenwich, beg to offer you our most sincere congratulations on the occasion of your 90th birthday. we cannot but feel how closely associated we are with you, in that our whole energies are directed to the maintenance and development of that practical astronomical work, of which you essentially laid the foundation. it affords us great pleasure to think that after the conclusion of your life's work, you have been spared to live so long under the shadow of the noble observatory with which your name was identified for half a century, and with which it must ever remain associated." after his return from playford he seemed to rally a little: but he soon fell ill and was found to be suffering from hernia. this necessitated a surgical operation, which was successfully performed on dec. 17th. this gave him effectual relief, and after recovering from the immediate effects of the operation, he lay for several days quietly and without active pain reciting the english poetry with which his memory was stored. but the shock was too great for his enfeebled condition, and he died peacefully in the presence of his six surviving children on jan. 2nd, 1892. he was buried in playford churchyard on jan. 7th. the funeral procession was attended at greenwich by the whole staff of the royal observatory, and by other friends, and at his burial there were present two former fellows of the college to which he had been so deeply attached. appendix. list of printed papers by g.b. airy. list of books written by g.b. airy. printed papers by g.b. airy. with the instinct of order which formed one of his chief characteristics airy carefully preserved a copy of every printed paper of his own composition. these were regularly bound in large quarto volumes, and they are in themselves a striking proof of his wonderful diligence. the bound volumes are 14 in number, and they occupy a space of 2 ft. 6 in. on a shelf. they contain 518 papers, a list of which is appended, and they form such an important part of his life's work, that his biography would be very incomplete without a reference to them. he was very careful in selecting the channels for the publication of his papers. most of the early papers were published in the transactions of the cambridge philosophical society, but several of the most important, such as his paper "on an inequality of long period in the motions of the earth and venus," were published in the philosophical transactions of the royal society, and others, such as the articles on "the figure of the earth," "gravitation," "tides and waves," &c., were published in encyclopaedias. after his removal to greenwich nearly all his papers on scientific subjects (except astronomy), such as tides, magnetism, correction of the compass, &c., &c., were communicated to the royal society, and were published in the philosophical transactions. but everything astronomical was reserved for the royal astronomical society. his connection with that society was very close: he had joined it in its earliest days (the date of his election was may 9th, 1828), and regarded it as the proper medium for the discussion of current astronomical questions, and for recording astronomical progress. he was unremitting in his attendance at the monthly meetings of the society, and was several times president. in the memoirs of the society 35 of his papers are printed, and in addition 129 papers in the monthly notices. in fact a meeting of the society rarely passed without some communication from him, and such was his wealth of matter that sometimes he would communicate as many as 3 papers on a single evening. for the publication of several short mathematical papers, and especially for correspondence on disputed points of mathematical investigation, he chose as his vehicle the philosophical magazine, to which he contributed 32 papers. investigations of a more popular character he published in the athenaeum, which he also used as a vehicle for his replies to attacks on his work, or on the establishment which he conducted: in all he made 55 communications to that newspaper. to various societies, such as the institution of civil engineers, the british association, the royal institution, &c., he presented papers or made communications on subjects specially suited to each; and in like manner to various newspapers: there were 58 papers in this category. in so long an official life there would naturally be a great number of official reports, parliamentary returns, &c., and these, with other miscellaneous papers printed for particular objects and for a limited circulation, amounted in all to 141. under this head come his annual reports to the board of visitors, which in themselves contain an extremely full and accurate history of the observatory during his tenure of office. there are 46 of these reports, and they would of themselves form a large volume of about 740 pages. the following summary of his printed papers shews the manner in which they were distributed: summary of printed papers by g.b. airy. number of papers. in the transactions of the cambridge philosophical society 30 in the philosophical transactions of the royal society 29 in the proceedings of the royal society 9 in the memoirs of the royal astronomical society 35 in the monthly notices of the royal astronomical society 129 in the philosophical magazine and journal 32 in the athenaeum 55 in encyclopedias, and in various newspapers and transactions 58 in official reports, addresses, parliamentary returns, evidence before committees, lectures, letters, sundry treatises, and papers 141 -- total 518 printed papers by g.b. airy. date when read or published. title of paper. where published. 1822 nov. 25 on the use of silvered glass for the mirrors camb. phil. soc. of reflecting telescopes. 1824 mar. 15 on the figure assumed by a fluid homogeneous camb. phil. soc. mass, whose particles are acted on by their mutual attraction, and by small extraneous forces. 1824 may 17 on the principles and construction of the camb. phil. soc. achromatic eye-pieces of telescopes, and on the achromatism of microscopes. 1824 trigonometry. encycl. metrop. 1825 feb. 21 on a peculiar defect in the eye, and a camb. phil. soc. mode of correcting it. 1825 may 2 on the forms of the teeth of wheels. camb. phil. soc. 1826 may 8 on laplace's investigation of the attraction camb. phil. soc. of spheroids differing little from a sphere. 1826 june 15 on the figure of the earth. phil. trans. 1826 nov. 26 on the disturbances of pendulums and camb. phil. soc. balances, and on the theory of escapements. 1827 feb. 15 remarks on a correction of the solar phil. trans. tables, required by mr south's observations. 1827 may 9 on some passages in mr ivory's remarks phil. mag. on a memoir by m. poisson relating to the attraction of spheroids. 1827 may 14 on the spherical aberration of the camb. phil. soc. may 21 eyepieces of telescopes. 1827 dec. 6 on the corrections in the elements of phil. trans. delambre's solar tables required by the observations made at the royal observatory, greenwich. 1828 feb. 26 address to the members of the senate, on an improvement in the position of the plumian professor. 1828 nov. 24 on the longitude of the cambridge observatory. camb. phil. soc. 1829 nov. 13 on a method of determining the mass of astr. soc. the moon from transit observations of (memoirs) venus near her inferior conjunction. 1829 nov. 16 on a correction requisite to be applied camb. phil. soc. to the length of a pendulum consisting of a ball suspended by a fine wire. 1829 dec. 14 on certain conditions under which a camb. phil. soc. perpetual motion is possible. 1830 aug. 17 figure of the earth. encycl. metrop. 1831 feb. 21 on the nature of the light in the two camb. phil. soc. rays produced by the double refraction of quartz. 1831 apr. 18 addition to the above paper. camb. phil. soc. 1831 nov. 14 on a remarkable modification of newton's camb. phil. soc. rings. 1831 nov. 24 on an inequality of long period in the phil. trans. motions of the earth and venus. 1832 jan. 2 translation of encke's dissertation (on encke's comet) contained in nos. 210 and 211 of the astronomische nachrichten. 1833 mar. 5 on a new analyzer, and its use in camb. phil. soc. experiments of polarization. 1832 mar. 19 on the phenomena of newton's rings when formed between two transparent substances of different refractive powers. 1832 may 2 report on the progress of astronomy trans brit. ass. during the present century. 1832 oct. report of the syndicate of the cambridge observatory. 1833 feb. 2 remarks on mr potter's experiment on phil. mag. interference. 1833 apr. 12 on the mass of jupiter, as determined r. astr. soc. from the observation of elongations of (memoirs) the fourth satellite. 1833 syllabus of a course of experimental lectures. 1833 may 7 on the calculation of newton's camb. phil. soc. experiments on diffraction. 1833 may 7 remarks on sir david brewster's paper phil. mag. "on the absorption of specific rays" &c. 1833 may 16 results of the repetition of mr potter's phil. mag. experiment of interposing a prism in the path of interfering light. 1833 may on a supposed black bar formed by phil. mag. diffraction. 1833 june 20 report on mr barlow's fluid-lens r. soc. (proc.) telescope 1834 mar. 14 continuation of researches into the value r. astr. soc. of the mass of jupiter, by observation of (memoirs.) the elongations of the fourth satellite. 1834 apr. 14 on the latitude of cambridge observatory camb. phil. soc. 1834 june report of the syndicate of the cambridge observatory. 1834 june 13 on the position of the ecliptic, as inferred r. astr. soc. inferred from transit and circle (memoirs.) observations made at cambridge observatory in the year 1833. 1834 june 13 observations of the solar eclipse of july r. astr. soc. 16th, 1833, made at cambridge observatory, (memoirs.) and calculations of the observations. 1834 nov. 24 on the diffraction of an object-glass camb. phil. soc. with circular aperture. 1834 dec. 3 on the calculation of the perturbations naut. alm. of the small planets and the comets of (1837, app.) short period. 1835 may 8 continuation of researches into the value r. astr, soc. of jupiter's mass. (memoirs.) 1835 june report of the syndicate of the cambridge observatory. 1835 june 12 on the position of the ecliptic, as r. astr. soc. inferred from observations with the (memoirs.) cambridge transit and mural circle, made in the year 1834. 1835 june 12 on the time of rotation of jupiter. r. astr. soc. (memoirs.) 1836 feb. 12 speech on delivering the medal of the r. astr. soc. r. astr. soc. to sir john herschel. (proc.) 1836 june 4 report of the astronomer royal to the board of visitors. 1836 june 9 report upon a letter (on a systematic r. soc. course of magnetic observations) addressed (proc.) by m. le baron de humboldt to his royal highness the president of the royal society (by s. hunter christie and g.b. airy). 1837 jan. 13 continuation of researches into the value r. astr. soc. of jupiter's mass. (memoirs.) 1837 feb. 10 speech on delivering the medal of the r. astr. soc. r. astr. soc. to professor rosenberger. (proc) 1837 mar. 10 results of the observations of the sun, r. astr. soc. moon, and planets, made at cambridge (memoirs) observatory in the years 1833, 1834, and 1835. 1837 may 12 on the position of the ecliptic, as r. astr. soc. inferred from observations with the (memoirs) cambridge transit and mural circle, made in the year 1835. 1837 june 3 report of the astronomer royal to the board of visitors. 1837 sept. 9 address delivered in the town hall of neath. 1837 nov. 10 on the parallax of alpha lyrae. r. astr. soc. (memoirs.) 1838 feb. 10 address to the earl of burlington on religious examination in the university of london. 1838 mar. 26 on the intensity of light in the camb. phil. soc. neighbourhood of a caustic. 1838 june 2 report of the astronomer royal to the board of visitors. 1838 dec. 14 a catalogue of 726 stars, deduced from r. astr. soc. the observations made at the cambridge (memoirs.) observatory, from 1828 to 1835; reduced to january 1, 1830. 1839 apr. 25 account of experiments on iron-built phil. trans. ships, instituted for the purpose of discovering a correction for the deviation of the compass produced by the iron of the ships. 1839 june 1 report of the astronomer royal to the board of visitors. 1839 nov. 8 on the determination of the orbits of r. astr. soc. comets, from observations. (memoirs.) 1839 article "gravitation." penny cyclop. 1839 article "greenwich observatory." penny cyclop. 1840 mar. 2 on a new construction of the camb. phil. soc. going-fusee. 1840 mar. 13 on the regulator of the clock-work for r. astr. soc. effecting uniform movement of equatoreals. 1840 may 15 on the correction of the compass in un. serv. journ. iron-built ships. (proc.) 1840 results of experiments on the disturbance j. weale. of the compass in iron-built ships. 1840 june 6 report of the astronomer royal to the board of visitors. 1840 june 18 on the theoretical explanation of an phil. trans. apparent new polarity in light. 1840 nov. 19 supplement to the above paper. phil. trans. 1840 dec. 4 on the diffraction of an annular aperture. phil. mag. 1840 dec. 9 remarks on professor challis's investigation phil. mag. of the motion of a small sphere vibrating in a resisting medium. 1841 jan. 20 correction to the above paper "on the phil. mag. diffraction," &c. 1841 mar. 22 remarks on professor challis's reply to phil. mag. mr airy's objections to the investigation of the resistance of the atmosphere to an oscillating sphere. 1841 june 5 report of the astronomer royal to the board of visitors. 1841 july 10 reply to professor challis, on the phil. mag. investigation of the resistance of the air to an oscillating sphere. 1841 oct. 26 extraordinary disturbance of the magnets. 1841 nov. 25 on the laws of the rise and fall of the phil. trans. tide in the river thames. 1841 dec. 21 report of the commissioners appointed to consider the steps to be taken for restoration of the standards of weight and measure. 1842 apr. 16 on the [greek: ichtis] of diodorus athenaeum. 1842 may 13 account of the ordnance zenith sector. r. astr. soc. (proc.) 1842 june 4 report of the astronomer royal to the board of visitors. 1842 nov. 11 observations of the total solar eclipse of r. astr. soc. 1842 july 7. (memoirs.) 1842 dec. 1 remarks on the present state of hatcliff's private charity (greenwich). 1842 article on tides and waves. encyc. metrop. 1843 mar. 2 on the laws of individual tides at phil. trans. southampton and at ipswich. 1843 apr. 29 on monetary and metrical systems. athenaeum. 1843 june 3 report of the astronomer royal to the board of visitors. 1843 sept. 25 address to the individual members of the board of visitors of the royal observatory (proposing the altazimuth). 1843 oct. 6 account of the northumberland equatoreal and dome, attached to the cambridge observatory. 1843 nov. 10 address and explanation of the proposed altitude and azimuth instrument to the board of visitors of the royal observatory. 1844 june 1 report of the astronomer royal to the board of visitors. 1844 dec. 12 on the laws of the tides on the coasts of phil. trans. ireland, as inferred from an extensive series of observations made in connection with the ordnance survey of ireland. 1845 jan. 10 on the flexure of a uniform bar r. astr. soc. supported by a number of equal pressures (memoirs.) applied at equidistant points, &c. 1845 feb. 14 speech on delivering the medal of the r. astr. soc. r. astr. soc. to capt. smyth (proc.) 1845 may 9 on a new construction of the divided r. astr. soc. eye-glass double-image micrometer. (memoirs.) 1845 june 7 report of the astronomer royal to the board of visitors. 1845 july 21 on wexford harbour. 1846 report of the gauge commissioners. and letter to sir e. ryan. 1846 may 7 on the equations applying to light under phil. mag. the action of magnetism. 1846 may 12 remarks on dr faraday's paper on phil. mag. ray-vibrations. 1846 may 25 on a change in the state of an eye camb. phil. soc. affected with a mal-formation. 1846 june 6 report of the astronomer royal to the board of visitors. 1846 june account of the measurement of an arc of r. astr. soc. longitude between the royal observatory (month. not.) of greenwich and the trigonometrical station of feagh main, in the island of valentia. 1846 july 25 letter to sir robert harry inglis, bart., athenaeum. m.p., in answer to sir james south's attack on the observations at the greenwich observatory. 1846 nov. on the bands formed by the partial phil. mag. interception of the prismatic spectrum. 1846 nov. 13 account of some circumstances historically r. astr. soc. connected with the discovery of the (memoirs.) planet exterior to uranus. 1847 jan. 8 reduction of the observations of halley's r. astr. soc. comet made at the cambridge observatory in (memoirs.) the years 1835 and 1836. 1847 jan. 8 on a proposed alteration of bessel's method r. astr. soc. for the computation of the corrections by (memoirs.) which the apparent places of stars are derived from the mean places. 1847 feb. on sir david brewster's new analysis of phil. mag. solar light. 1847 feb. 20 on the name of the new planet. athenaeum. 1847 feb. 27 mr adams and the new planet. athenaeum. 1847 plan of the buildings and grounds of the royal observatory, greenwich, with explanation and history. 1847 may 14 explanation of hansen's perturbations of r. astr. soc. the moon by venus. (month. not.) 1847 june 5 report of the astronomer royal to the board of visitors. 1847 nov. 30 address to the individual members of the board of visitors of the royal observatory. (zenith tube.) 1847 dec. 10 results deduced from the occultations of r. astr. soc. stars and planets by the moon, observed (memoirs.) at cambridge observatory from 1830 to 1835. 1848 feb. 11 abstract of struve's "ã�tudes d'astronomie r. astr. soc. stellaire." (month. not.) 1848 mar. 13 syllabus of lectures on astronomy to be delivered at the temperance hall, ipswich. 1848 apr. 10 remarks on prof. challis's theoretical phil. mag. determination of the velocity of sound 1848 may 8 supplement to a paper on the intensity of camb. phil. soc. light in the neighbourhood of a caustic. 1848 may 12 address to individual members of the board of visitors. (new transit circle, reflex zenith tube, &c.) 1848 june 3 report of the astronomer royal to the board of visitors. 1848 june 9 corrections of the elements of the moon's r. astr. soc. orbit, deduced from the lunar (memoirs.) observations made at the royal observatory, of greenwich from 1750 to 1830. 1848 aug. 9 explanation of a proposed construction of zenith sector: addressed to the board of visitors of the royal observatory, greenwich. 1848 oct. 14 on the construction of chinese balls athenaeum. 1849 description of the instruments of process used in the photographic self-registration of the magnetical and meteorological instruments at the royal observatory, greenwich. 1849 description of the altitude and azimuth instrument erected at the royal observatory, greenwich, in the year 1847. 1849 astronomy. (tract written for the scientific manual.) 1849 mar. 9 substance of the lecture delivered by the r. astr. soc. astronomer royal on the large reflecting (month. not.) telescopes of the earl of rosse and mr lassell. 1849 june on a difficulty in the problem of sound. phil. mag. 1849 june 2 report of the astronomer royal to the board of visitors. 1849 june 8 on instruments adapted to the measure of r. astr. soc. small meridional zenith distances. (month. not.) 1849 nov. 9 results of the observations made by the r. astr. soc. rev. fearon fallows at the royal (memoirs.) observatory, cape of good hope, in the years 1829, 1830, 1831. 1849 nov. 9 on bell's calculating machine, and on r. astr. soc. lord rosse's telescope. (month. not.) 1849 nov. 10 on the exodus of the israelites. athenaeum. 1849 dec. 14 on the method of observing and recording r. astr. soc. transits, lately introduced in america, &c. (month. not.) 1850 jan. 10 on a problem of geodesy. phil. mag. 1850 feb. 8 address on presenting the medal of the r. astr. soc. r. astr. soc. to m. otto von struve. (month. not.) 1850 mar. 15 on the present state and prospects of the r. inst. science of terrestrial magnetism. 1850 mar. 16 on the exodus of the israelites athenaeum. 1850 mar. 30 on the exodus of the israelites. athenaeum. 1850 may 10 statement concerning assistance granted r. astr. soc. by the admiralty to hansen--also on (month. not.) henderson's numbers for the teeth of wheels. 1850 may 10 on the weights to be given to the separate r. astr. soc. results for terrestrial longitudes, (memoirs.) determined by the observation of transits of the moon and fixed stars. 1850 june 1 report of the astronomer royal to the board of visitors. 1850 june 14 letter from hansen on his lunar tables.--valz r. astr. soc. on an arrangement of double-image (month. not.) micrometer.--on the computation of longitude from lunar transits 1850 dec. 13 on a method of regulating the clock-work r. astr. soc. for equatoreals. (month. not.) 1850 dec. 13 supplement to a paper "on the regulation r. astr. soc. of the clock-work for effecting uniform (memoirs.) movement of equatoreals." 1850 dec. 27 on the relation of the direction of the phil. trans. wind to the age of the moon, as inferred from observations made at the royal observatory, greenwich, from 1840 nov. to 1847 dec. 1851 jan. 14 remarks on mr wyatt's paper on the inst. c.e. construction of the building for the (minutes.) exhibition of the works of industry of all nations in 1851. 1851 feb. 15 address on presenting the medal of the r. astr. soc. r. astr. soc. to dr annibale de (month. not.) gasparis. 1851 mar. 28 letter to professor challis regarding the adams prize. 1851 mar. 29 on caesar's place of landing in britain. athenaeum. 1851 suggestions to astronomers for the brit. assoc. observation of the total eclipse of the sun on july 28, 1851. 1851 apr. 11 on the determination of the probable r. astr. soc. stability of an azimuthal circle by (month. not.) observations of star and a permanent collimator. 1851 may 2 on the total solar eclipse of 1851, july 28. r. inst. (lecture.) 1851 may 9 on the vibration of a free pendulum in an r. astr. soc. oval differing little from a straight line (memoirs) 1851 june 7 report of the astronomer royal to the board of visitors. 1851 july 2 the president's address to the twenty-first athenaeum. meeting of the british association for the advancement of science, ipswich. 1851 oct. 17 on julius caesar's expedition against naut. mag. england, in relation to his places of departure and landing. 1851 nov. 14 account of the total eclipse of the sun on r. astr. soc. 1851, july 28, as observed at gã¶ttenburg, (memoirs.) at christiania, and at christianstadt. 1851 dec. 13 on the geography of the exodus. athenaeum. 1852 jan. 9 on the solar eclipse of july 28, 1851. r. astr. soc. (month. not.) 1852 on the place of caesar's departure from soc. of antiq. gaul for the invasion of britain, and (memoirs.) the place of his landing in britain, with an appendix on the battle of hastings. 1852 on a new method of computing the naut. alm. 1856, perturbations of planets, by j.f. app. encke--translated and illustrated with notes by g.b. airy. 1852 june 5 report of the astronomer royal to the board of visitors. 1853 feb. 3 on the eclipses of agathocles, thales, phil. trans. and xerxes. 1853 feb. 4 lecture on the results of recent r. inst. calculations on the eclipse of thales and eclipses connected with it. 1853 may 3 address to the individual members of the board of visitors of the royal observatory, greenwich. (lunar reductions.) 1853 may 14 on decimal coinage. athenaeum. 1853 june 4 report of the astronomer royal to the board of visitors. 1853 june lecture on the determination of the r. astr. soc. longitude of the observatory of (month. not.) cambridge by means of galvanic signals. 1853 sept. 10 on decimal coinage. athenaeum. 1853 dec. 14 description of the transit circle of the royal observatory, greenwich. (app. gr. observ. 1852.) 1853 dec. 14 regulations of the royal observatory, greenwich. (app. gr. observ. 1852.) 1854 jan. 14 on the telegraphic longitude of brussels. athenaeum. 1854 feb. 10 address on presenting the gold medal of r. astr. soc. the r. astr. soc. to mr charles rã¼mker. (month. not.) 1854 feb. 25 on reforms in the university of cambridge. athenaeum. 1854 apr. 15 letters relating to "the late m. mauvais." liter. gaz. 1854 june 3 report of the astronomer royal to the board of visitors. 1854 sept. the deluge. private. 1854 oct. 28 on the correction of the compass in iron athenaeum. ships. (scoresby's experiments.) 1854 nov. 10 on the difference of longitude between r. astr. soc. the observatories of brussels and greenwich, (memoirs.) as determined by galvanic signals. 1855 jan. 1 lecture at s. shields on the pendulum experiments in the harton pit, and letter on the results. 1855 feb. 2 lecture on the pendulum experiments r. inst. lately made in the harton colliery for ascertaining the mean density of the earth. 1855 feb. 3 on the correction of the compass in iron athenaeum. ships. (remarks on dr scoresby's investigations.) 1855 address on presenting the medal of the r. astr. soc. r. astr. soc. to the rev. william rutter (month. not.) dawes. 1855 feb. 15 on the computation of the effect of the phil. trans. attraction of mountain masses, as disturbing the apparent astronomical latitude of stations in geodetic surveys. 1855 june 2 report of the astronomer royal to the board of visitors. 1855 oct. 18 address to the individual members of the board of visitors of the royal observatory, greenwich. (equatoreal.) 1855 nov. 21 remarks upon certain cases of personal r. astr. soc. equation which appear to have hitherto (memoirs.) escaped notice, accompanied with a table of results. 1855 nov. 22 discussion of the observed deviations of phil. trans. the compass in several ships, wood-built and iron-built: with a general table for facilitating the examination of compass-deviations. 1855 description of the reflex zenith tube of the royal observatory, greenwich. (app. to the greenwich obs. for 1854.) 1856 jan. 9 on professor peirce's criterion for astr. journ. discordant observations. (cambr.) 1856 jan. 24 account of pendulum experiments undertaken phil. trans. in the harton colliery, for the purpose of determining the mean density of the earth. 1856 june 7 report of the astronomer royal to the board of visitors. 1856 aug. 25 on scheutz's calculating machine. phil. mag. 1856 aug. 30 science and the government. (reply to athenaeum. statements in the morning chronicle about the instrumental equipment of the royal observatory.) 1857 may 8 on the means which will be available for r. astr. soc. correcting the measure of the sun's (month. not.) distance in the next twenty-five years. 1857 may 12 knowledge expected in computers and assistants in the royal observatory. 1857 june 6 report of the astronomer royal to the board of visitors. 1857 june 12 on the eclipse of agathocles, the eclipse r. astr. soc. at larissa, and the eclipse of thales. (memoirs.) with an appendix on the eclipse of stiklastad. 1857 june 18 account of the construction of the new phil. trans. national standard of length, and of its principal copies. 1857 dec. 5 letter to the vice-chancellor of cambridge university regarding smith's prizes. 1857 dec. 7 on the substitution of methods founded camb. phil. soc. on ordinary geometry for methods based on the general doctrine of proportions, in the treatment of some geometrical problems 1857 description of the galvanic chronographic gr. obs. 1856, apparatus of the royal observatory, app. greenwich. 1858 mar. 8 suggestions for observation of the annular eclipse of the sun on 1858, march 14-15. 1858 mar. 12 note on oltmann's calculation of the r. astr. soc. eclipse of thales. also on a method (month. not.) of very approximately representing the projection of a great circle upon mercator's chart. 1858 may the atlantic cable problem. naut. mag. 1858 may 20 report of the ordnance survey commission; together with minutes of evidence and appendix. 1858 june 5 report of the astronomer royal to the board of visitors. 1858 june 16 on the mechanical conditions of the phil. mag. deposit of a submarine cable. 1858 july instructions and chart for observations r. astr. soc. of mars in right ascension at the (special.) opposition of 1860 for obtaining the measure of the sun's distance. 1858 aug. 20 on the advantageous employment of photog. notes. stereoscopic photographs for the representation of scenery. 1858 nov. 6 on the "draft of proposed new statutes athenaeum. for trinity college, cambridge." 1858 nov. 20 letter to the vice-chancellor of the university of cambridge, offering the sheepshanks endowment. 1858 dec. 6 suggestion of a proof of the theorem camb. phil. soc. that every algebraic equation has a root. 1859 manual of astronomy--for the admiralty. parly. paper. 1859 feb. 1 letter to lord monteagle relating to the standards of weights and measures. 1859 feb. 4 remarks on mr cayley's trigonometrical phil. mag. theorem, and on prof. challis's proof that equations have roots. 1859 mar. 11 on the movement of the solar system in r. astr. soc. space. (memoirs.) 1859 apr. 8 on the apparent projection of stars upon r. astr. soc. the moon's disc in occultations. also (month. not.) comparison of the lunar tables of burckhardt and hansen with observations of the moon made at the royal observatory, greenwich. 1859 apr. 8 on the apparent projection of stars upon r. astr. soc. the moon's disc in occultations. (memoirs.) 1859 june 4 report of the astronomer royal to the board of visitors. 1859 june 10 abstract of maxwell's paper "on the r. astr. soc. stability of the motion of saturn's rings." (month. not.) 1859 july 8 corrections of the elements of the moon's r. astr. soc. orbit, deduced from the lunar observations (memoirs.) made at the royal observatory of greenwich from 1750 to 1851. 1859 sept. 10 on the invasion of britain by julius caesar. athenaeum. (answer to mr lewin.) 1859 nov. 12 on iron ships--the royal charter. athenaeum. (answer to archibald smith's remarks.) 1859 nov. circular requesting observations of small planets. 1859 dec. 9 notice of the approaching total eclipse of r. astr. soc. the sun of july 18,1860, and suggestions (month. not.) for observation. 1859 dec. 12 supplement to a proof of the theorem camb. phil. soc. that every algebraic equation has a root. 1860 jan. 13 description of the new equatoreal at the r. astr. soc. royal observatory, greenwich. also (month. not.) abstract of an essay by gen. t.f. de schubert on the figure of the earth. 1860 jan. 28 on the claudian or plautian invasion of athenaeum britain. 1860 feb. 2 examination of navy 2-foot telescopes at the royal observatory, greenwich, 1860, jan. 31 to feb. 2. 1860 feb. 11 report on the instrumental equipments ho. of commons. of the exchequer office of weights and (parly. paper.) measures, as regards the means for preventing fraud in the sale of gas to the public; and on the amendments which may be required to the existing legislation on that subject. 1860 mar. 9 address on the approaching solar eclipse r. astr. soc. of july 18, 1860, &c. (month. not.) 1860 may 10 correspondence between the lords ho. of commons. commissioners of her majesty's treasury, (parly. paper.) &c., and the astronomer royal, relating to gas measurement, and the sale of gas act. 1860 june 2 report of the astronomer royal to the board of visitors. and address to the members of the board in reference to struve's geodetic suggestions. 1860 june 7 correspondence regarding the grant of _â£1000_ to prof. hansen for his lunar tables. 1860 sept. 13 remarks on a paper entitled "on the polar distances of the greenwich transit circle, by a. marth." addressed to the members of the board of visitors. 1860 sept. 22 on change of climate, in answer to athenaeum. certain speculations by sir henry james. 1860 oct. 20 circular relating to the distribution of greenwich observations and other publications of the royal observatory. 1860 nov. 9 account of observations of the total r. astr. soc. solar eclipse of 1860, july 18, made (month. not.) at hereã±a, near miranda de ebro; &c. &c. 1860 nov. 17 on change of climate: further discussion. athenaeum. 1860 letters on lighthouses, to the commission on lighthouses. 1860 dec. 14 note on the translation of a passage in a r. astr. soc. letter of hansen's relating to (month. not.) coefficients. 1861 feb. 9 on the temperature-correction of syphon athenaeum. barometers. 1861 march results of observations of the solar r. astr. soc. eclipse of 1860 july 18 made at the royal (month. not.) observatory, greenwich, for determination of the errors of the tabular elements of the eclipse. also suggestion of a new astronomical instrument, for which the name "orbit-sweeper" is proposed. also theory of the regulation of a clock by galvanic currents acting on the pendulum. 1861 june 1 report of the astronomer royal to the board of visitors. 1861 june 5 on a supposed failure of the calculus of phil. mag. variations. 1861 july report of a committee of the r. soc. on r. soc.(proc.) the advisability of re-measuring the indian arc of meridian. 1861 sept. 21 lecture at manchester on the great solar athenaeum. eclipse of july 18, 1860. 1861 sept. 21 the same lecture. london review. 1861 oct. examination paper for the sheepshanks exhibition. 1861 nov. 1 translation of dr lamont's paper "on the phil. mag. most advantageous form of magnets." 1861 nov. 8 note on a letter received from hansen on r. astr. soc. the lunar theory. also discussion of (month. not.) a result deduced by mr d'abbadie from observations of the total solar eclipse of 1860, july 18. 1861 nov. 16 instructions for observing the total eclipse of the sun on december 31. 1861 dec. on a projection by balance of errors for phil. mag. maps. 1861 dec. 28 on the circularity of the sun's disk. r. astr. soc. also table of comparative number of (month. not.) observations of small planets. 1862 jan. on the direction of the joints in the phil. mag. faces of oblique arches. 1862 mar. 15 review of "an historical survey of the athenaeum. astronomy of the ancients" by the rt hon. sir g. cornewall lewis. 1862 apr. 24 notes for the committee on weights and measures, 1862. 1862 may 15 on the magnetic properties of hot-rolled phil. trans. and cold-rolled malleable iron. 1862 june 7 report of the astronomer royal to the board of visitors. 1862 june 24 evidence given before the select committee on weights and measures. 1862 oct. 4 biography of g.b. airy (probably in part london review. based upon data supplied by himself). 1862 oct. 11 abstract of paper "on the strains in the athenaeum. interior of beams and tubular bridges." 1862 oct. 11 translation of a letter from prof. lament phil. mag. on dalton's theory of vapour, &c. 1862 nov. 6 on the strains in the interior of beams. phil. trans. 1862 nov. correspondence with sabine concerning his attack on the greenwich magnetic observations. (confidentially communicated to the board of visitors.) 1862 nov. 21 evidence given before the public schools commission. 1862 nov. abstract of m. auwers's paper on the r. astr. soc. proper motion of procyon, and note on (month. not.) same. 1862 dec. abstract of mr safford's paper on the r. astr. soc. proper motion of sirius. also on the (month. not.) forms of lenses proper for the negative eye-pieces of telescopes. also on the measurements of the earth, and the dimensions of the solar system. also on fringes of light in solar eclipses. 1863 jan. address to the board of visitors on a further attack by sabine on the greenwich magnetic observations (confidential). 1863 jan. 9 on the observations of saturn made at r. astr. soc. pulkowa and greenwich. (month. not.) 1863 feb. 24 report to the board of trade on the proposed lines of railway through greenwich park. 1863 mar. 2 determination of the longitude of valencia in ireland by galvanic signals in the summer of 1862 (app. iii. to the gr. astr. obsns. 1862). 1863 mar. 13 on the movement of the solar system in r. astr. soc. space, deduced from the proper motions (memoirs.) of 1167 stars. by edwin dunkin (for g.b.a.). 1863 mar. 13 on the visibility of stars in the pleiades r. astr. soc. to the unarmed eye. (month. not.) 1863 mar. 21 on marriage odes. athenaeum. 1863 apr. 9 further report as to the probable effects of the london, chatham and dover railway on the royal observatory in greenwich park. 1863 apr. 10 determination of the sun's parallax from r. astr. soc. observations of mars during the (month. not.) opposition of 1862. by e.j. stone (for g.b.a.). also remarks on struve's account of a local deviation in the direction of gravity, near moscow. also an account of an apparatus for the observation of the spectra of stars, and results obtained. 1863 apr. 23 on the diurnal inequalities of phil. trans. terrestrial magnetism, as deduced from observations made at the royal observatory, greenwich, from 1841 to 1857. 1863 may 8 on the discordance between the results r. astr. soc. for zenith-distances obtained by direct (memoirs.) observation, and those obtained by observation by reflection from the surface of quicksilver. 1863 june 6 report of the astronomer royal to the board of visitors. 1863 july 2 on the amount of light given by the r. astr. soc. moon at the greatest stage in the (month. not.) excentrically-total eclipse, 1863, june 1. 1863 aug. plan of the buildings and grounds of the royal observatory, greenwich, with explanation and history. 1863 sept. 5 on the origin of the apparent luminous r. astr. soc. band which, in partial eclipses of the (month. not.) sun, has been seen to surround the visible portion of the moon's limb. 1863 sept. 5 on the invasions of britain by julius athenaeum. 1863 oct. 3 caesar. 1863 oct. 17 the earthquake as observed from greenwich. athenaeum. 1863 nov. on the numerical expression of the phil. mag. destructive energy in the explosions of steam-boilers, &c. 1863 nov. 13 convention arranged between m. le verrier r. astr. soc. and the astronomer royal for meridional (month. not.) observations of the small planets, &c. 1863 nov. 13 translation of hansen's paper r. astr. soc. "calculation of the sun's parallax (month. not.) from the lunar theory," with notes by g.b.a. 1863 dec. 17 first analysis of 177 magnetic storms, phil. trans. registered by the magnetic instruments in the royal observatory, greenwich, from 1841 to 1857. 1864 jan. 8 pontã©coulant's paper "sur le coefficiant r. astr. soc. de l'ã�quation parallactique dã©duit de la (month. not.) thã©orie," with notes by g.b.a. 1864 jan. 26 remarks on redman's paper on the east inst. c. e. coast (chesil bank, &c.). (minutes.) 1864 mar. 10 note on a passage in capt. r. astr. soc. jacob's "measures of jupiter," &c. (month. not.) 1864 mar. 11 notes for the committee on weights and ho. of comm. measures, 1862. (parly. paper.) 1864 mar. 17 on a method of slewing a ship without inst. nav. arch. the aid of the rudder. 1864 apr. 5 comparison of the chinese record of solar r. astr. soc. eclipses in the chun tsew with the (month. not.) computations of modern theory. 1864 june 4 report of the astronomer royal to the board of visitors. 1864 june 10 on the transit of venus, 1882, dec. 6. r. astr. soc. (month. not.) 1864 june 10 on the bright band bordering the moon's r. astr. soc. limb in photographs of eclipses. (month. not.) 1864 notes on methods of reduction applicable to the indian survey. 1864 sept. 3 a visit to the corryvreckan. athenaeum. 1864 sept. 29 examination paper for the sheepshanks scholarship. 1865 jan. 13 comparison of the transit-instrument in r. astr. soc. its ordinary or reversible form with the (month. not.) transit-instrument in its non-reversible form, as adopted at greenwich, the cape of good hope, and other observatories. 1865 mar. 9 syllabus of a course of three lectures on "magnetical errors, &c., with special reference to iron ships and their compasses," delivered at the south kensington museum. 1865 apr. 1 remarks on mr ellis's lecture on the horolog. journ. greenwich system of time signals. 1865 apr. 1 free translation of some lines of virgil, athenaeum. "citharã¢ crinitus iopas," &c. 1865 june 3 report of the astronomer royal to the board of visitors. 1865 june 17 note on my recommendation (in 1839) athenaeum. of government superintendence of the compasses of iron ships. also note on the birthplace of thomas clarkson. 1865 july on hemiopsy. phil. mag. 1865 aug. 22 on the value of the moon's semidiameter r. astr. soc. as obtained by the investigations of (month. not.) hugh breen, esq., from occultations observed at cambridge and greenwich. 1865 sept. 16 on "the land of goshen"--reply to "a athenaeum. suffolk incumbent." 1865 oct. 21 address of the astronomer royal to the individual members of the board of visitors. (on improved collimators.) 1865 oct. 23 note on an error of expression in two r. astr. soc. previous memoirs. also description and (month. not.) history of a quadrant made by abraham sharp. 1865 nov. 11 on the possible derivation of the national athenaeum. name "welsh." 1865 essays on the invasion of britain by julius private. caesar; the invasion of britain by plautius, and by claudius caesar; the early military policy of the romans in britain; the battle of hastings. (with corr.) 1866 mar. 10 on "the compass in iron ships." objections athenaeum. to passages in a lecture by archibald smith. 1866 apr. 13 on the supposed possible effect of r. astr. soc. friction in the tides, in influencing the (month. not.) apparent acceleration of the moon's mean motion in longitude. also on a method of computing interpolations to the second order without changes of algebraic sign. 1866 june 2 report of the astronomer royal to the board of visitors. 1866 july 17 papers relating to time signals on the ho. of comm. start point. (parly. paper.) 1866 sept. 1 on the campaign of aulus plautius in athenaeum. britain. (reply to dr guest.) 1866 nov. 19 on the continued change in an eye camb. phil. soc. affected with a peculiar malformation. 1866 dec. on the simultaneous disappearance of r. astr. soc. jupiter's satellites in the year 1867. (month. not.) also inference from the observed movement of the meteors in the appearance of 1866, nov. 13-14. 1867 jan. 1 memorandum for the consideration of the commission on standards. (policy of introducing metrical standards.) 1867 jan. 12 on decimal weights and measures. athenaeum. 1867 feb. 19 on the use of the suspension bridge with inst. c.e. stiffened roadway for railway and other (minutes.) bridges of great span. 1867 mar. 21 computation of the lengths of the waves phil. trans. of light corresponding to the lines in the dispersion spectrum measured by kirchhoff. 1867 mar. corresponding numbers of elevation in r. obs. (also english feet, and of readings of aneroid meteor. soc. or corrected barometer in english apr. 17, 1867.) inches. 1867 apr. 16 remarks on sir w. denison's paper on inst. c.e. "the suez canal." (minutes.) 1867 may 3 statement of the history and position of private. the blue-coat girls' school, greenwich. 1867 june 1 report of the astronomer royal to the board of visitors. 1867 june 14 on certain appearances of the telescopic r. astr. soc. images of stars described by the rev. (month. not.) w.r. dawes. 1867 dec. 13 note on the total solar eclipse of 1868, r. astr. soc. aug. 17-18. (month. not.) 1868 biography of g.b. airy. (probably corrected by himself.) 1868 jan. 4 biography (with portrait) of g.b. airy. ill. lond. news. (probably corrected by himself.) 1868 feb. 6 comparison of magnetic disturbances phil. trans. recorded by the self-registering magnetometers at the royal observatory, greenwich, with magnetic disturbances deduced from the corresponding terrestrial galvanic currents recorded by the self-registering galvanometers of the royal observatory. 1868 mar. 13 address of the astronomer royal to the individual members of the board of visitors. (number of copies of observations.) 1868 june 6 report of the astronomer royal to the board of visitors. 1868 july 24 first report of the commissioners appointed parly. paper. to enquire into the condition of the exchequer standards. 1868 sept. 19 the inundation at visp. athenaeum. 1868 nov. 9 on the factorial resolution of the trinomial camb. phil. soc. x^n 2cos n. a. + 1/x^n. 1868 dec. 10 on the diurnal and annual inequalities phil. trans. of terrestrial magnetism, as deduced from observations made at the royal observatory from 1858 to 1863, &c. 1868 dec.11 on the preparatory arrangements for the r. astr. soc. observation of the transits of venus (month. not.) 1874 and 1882. 1868 dec. 12 on the migrations of the welsh nations. athenaeum. 1869 mar. 8 memorandum by the chairman (on the use of the troy weight) for the consideration of the members of the standards commission. 1869 apr. 3 second report of the commissioners appointed parly. paper. to enquire into the condition of the exchequer (now board of trade) standards.--the metric system. 1869 april syllabus of lectures on magnetism to be delivered in the university of cambridge. 1869 apr. 27 remarks on shelford's paper "on the inst. c.e. outfall of the river humber." (minutes.) 1869 june 1 memorandum for the consideration of the standards commission, on the state of the question now before them regarding the suggested abolition of troy weight. 1869 june 5 report of the astronomer royal to the board of visitors. 1869 supplementary memorandum by the astronomer royal on the proposed abolition of troy weight. 1869 july 6 correspondence between the treasury, the ho. of comm. admiralty, and the astronomer royal, (parly. paper.) respecting the arrangements to be made for observing the transits of venus, which will take place in the years 1874 and 1882. 1869 aug. 7 note on atmospheric chromatic dispersion r. astr. soc. as affecting telescopic observation, and (month. not.) on the mode of correcting it. 1869 oct. 19 description of the great equatoreal of the royal observatory, greenwich. greenwich observations, 1868. app. 1870 feb. 3 note on an extension of the comparison phil. trans. of magnetic disturbances with magnetic effects inferred from observed terrestrial galvanic currents; &c. &c. 1870 apr. 8 on the question of a royal commission journ. soc. arts. for science. 1870 may 2 letters to the first lord of the admiralty enclosing application of the assistants for an increase of salaries. 1870 may 13 on decimal and metrical systems. journ. soc. arts. 1870 june 4 report of the astronomer royal to the board of visitors. 1870 aug. 27 on the meaning of the word "whippultree." athenaeum. 1870 oct. 22 on the locality of "paradise." athenaeum. 1870 nov. 12 on the locality of the roman gesoriacum. athenaeum. 1870 nov. 30 recommendation of prof. miller for a r. soc.(proc.) royal medal of the royal society. (quoted by the president.) 1870 revised edition of "astronomy." man. naut. sci. 1871 jan. 21 the burial of sir john moore. athenaeum. 1871 mar. 14 letter to the hydrographer of the admiralty on the qualifications and claims of the assistants of the royal observatory. 1871 apr. 5 remarks on the determination of a ship's r. soc. (proc.) place at sea. 1871 may 2 remarks on samuelson's paper "description inst. c.e. of two blast furnaces," &c. (minutes.) 1871 may 3 note on barometric compensation of the phil. mag. pendulum. 1871 june 3 report of the astronomer royal to the board of visitors. 1871 june 9 remarks on mr abbott's observations on r. astr. soc. eta argã»s. also on a.s. herschel's and (month. not.) j. herschel's mechanism for measuring time automatically in taking transits. 1871 erratum in results of greenwich r. astr. soc. observations of the solar eclipse of 1860, (month. not.) july 18. also observations of the solar eclipse of 1870, dec. 21-22, made at the royal observatory, greenwich. 1871 aug. investigation of the law of the progress phil. mag. of accuracy in the usual process for forming a plane surface. 1871 nov.16 corrections to the computed lengths of phil. trans. waves of light for kirchhoff's spectral lines. 1871 on a supposed alteration in the amount r. soc. (proc.) of astronomical aberration of light, produced by the passage of the light through a considerable thickness of refracting medium. 1871 nov. 29 biography of g.b. airy. (probably daily telegraph. corrected by himself.) 1871 dec. 8 note on a special point in the r. astr. soc. determination of the elements of the (month. not.) moon's orbit from meridional observations of the moon. 1871 dec. 26 proposed devotion of an observatory to r. astr. soc. observation of the phenomena of jupiter's (month. not.) satellites. 1872 jan. address to the council of the royal society on the propriety of continuing the grant to the kew observatory for meteorological observations. 1872 feb. 8 experiments on the directive power of phil. trans. large steel magnets, of bars of magnetized soft iron, and of galvanic coils, in their action on external small magnets--with appendix by james stuart. 1872 feb. 12 further observations on the state of an camb. phil. soc. eye affected with a peculiar malformation. 1872 mar. 20 notes on scientific education, submitted to the royal commission on scientific instruction and the advancement of science. 1872 may 9 on a supposed periodicity in the r. soc. (proc.) elements of terrestrial magnetism, with a period of 26-1/4 days. 1872 nov. 30 address (as president) delivered at the anniversary meeting of the royal society. 1872 dec. 19 magnetical observations in the phil. trans. britannia and conway tubular iron bridges. 1873 feb. 25 remarks on mr thornton's paper on inst. c.e. "the state railways of (minutes.) india"--chiefly in reference to the proposed break of gauge. 1873 mar. 12 note on the want of observations of r. astr. soc. eclipses of jupiter's first satellite (month. not.) from 1868 to 1872. 1873 mar. 14 letter to the secretary of the r. astr. soc. admiralty on certain articles which (month. not.) had appeared in the public newspapers in regard to the approaching transit of venus. 1873 additional note to the paper on a r. soc. (proc.) supposed alteration in the amount of astronomical aberration of light produced by the passage of the light through a considerable thickness of refracting medium. 1873 apr. 10 list of candidates for election into the royal society--classified. 1873 on the topography of the "lady of private. the lake." 1873 june 7 report of the astronomer royal to the board of visitors. 1873 nov. 14 on the rejection, in the lunar r. astr. soc. theory, of the term of longitude (month. not.) depending for argument on eight times the mean longitude of venus minus thirteen times the mean longitude of the earth, introduced by prof. hansen; &c. 1873 dec. 1 address (as president) delivered at the anniversary meeting of the royal society. 1874 jan. on a proposed new method of treating r. astr. soc. the lunar theory. (month. not.) 1874 may 4 british expeditions for the observation of the transit of venus, 1874, december 8. instructions to observers. 1874 june 6 report of the astronomer royal to the board of visitors. 1874 aug. 6 regulations of the royal observatory, greenwich. appendix to the greenwich observations, 1873. 1874 oct. 3 science and art. the moon as carved athenaeum. on lee church. 1874 nov. 13 preparations for the observation of the r. astr. soc. transit of venus 1874, december 8-9. (month. not.) 1874 nov. 17 remarks on the paper "on the nagpur inst. c.e. waterworks." (minutes.) 1874 dec. telegrams relating to the observations r. astr. soc. of the transit of venus 1874, dec. 9. (month. not.) 1875 feb. 2 remarks on mr prestwich's paper on the inst. c.e. origin of the chesil bank. (minutes.) 1875 feb 25 letter to the rev. n. m. ferrers, on the subject of the smith's prizes. 1875 mar. 12 on the method to be used in reducing r. astr. soc. the observations of the transit of (month. not.) venus 1874, dec. 8. 1875 mar. report on the progress made in the r. astr. soc. calculations for a new method of (month. not.) treating the lunar theory. 1875 june 5 report of the astronomer royal to the board of visitors. 1875 june 7 apparatus for final adjustment of the horolog. journ. thermal compensation of chronometers, by the astronomer royal. 1875 nov. chart of the apparent path of mars, 1877, r. astr. soc. with neighbouring stars. also (month. not.) spectroscopic observations made at the royal observatory, greenwich. also observations of the solar eclipse of 1875, september 28-29, made at the royal observatory, greenwich. 1876 jan. report by the astronomer royal on the r. astr. soc. present state of the calculations in his (month. not.) new lunar theory. 1876 jan. 27 note on a point in the life of sir william athenaeum. herschel. 1876 mar. 15 evidence given before the government committee on the meteorological committee. 1876 may 20 on toasting at public dinners. public opinion. 1876 june 3 report of the astronomer royal to the board of visitors, 1876 aug. 7 on a speech attributed to nelson. athenaeum. 1876 dec. spectroscopic results for the rotation of r. astr. soc. jupiter and of the sun, obtained at the (month. not.) royal observatory, greenwich. 1877 jan. stars to be compared in r.a. with mars, r. astr. soc. 1877, for determination of the parallax (month. not.) of mars. 1877 mar. note by the astronomer royal on the r. astr. soc. numerical lunar theory. also remarks (month. not.) on le verrier's intra-mercurial planet. also on observations for the parallax of mars. 1877 mar. 27 remarks on a paper on "the river inst. c.e. thames." (minutes.) 1877 apr. on observing for le verrier's intra-mercurial r. astr. soc. planet. also on the parallax of (month. not.) mars, and mr gill's proposed expedition. 1877 may on the vulgar notion that the sun or moon the observatory is smallest when overhead. (no. 2). 1877 june 2 report of the astronomer royal to the board of visitors. 1877 july 16 report on the telescopic observations of ho. of commons the transit of venus 1874, made in the parly. paper. expedition of the british government, and on the conclusion derived from those observations. 1877 sept. 13 on spurious discs of stars produced by the observatory oval object-glasses. (no. 7). 1877 sept. 24 obituary notice of the work of le daily news. verrier--died sept. 23, 1877. 1877 nov. 20 on the value of the mean solar parallax the observatory &c. from the british telescopic observations (no. 8). of the transit of venus 1874. also remarks on prof. adams's lunar theory. 1877 nov. on the inferences for the value of mean r. astr. soc. solar parallax &c. from the telescopic (month. not.) observations of the transit of venus 1874, which were made in the british expedition for the observation of that transit. 1877 numerical lunar theory: appendix to greenwich astronomical observations 1875. 1877 dec. 6 on the tides at malta. phil. trans. 1878 correspondence with le verrier on his the observatory planetary tables in 1876. (no. 10). 1878 on the proposal of the french committee the observatory to erect a statue to le verrier. also (no. 13). on the observation of the approaching transit of mercury. 1878 mar. 11 on the correction of the compass in phil. mag. iron ships without use of a fixed mark. 1878 mar. 30 on the standards of length in the the times. guildhall, london. 1878 apr. 27 report of lecture on "the probable w. cumberland condition of the interior of the times. earth." on the probable condition of the trans. of the interior of the earth--revised cumberland edition of above lecture. assoc., &c. 1878 june 1 discussion of the observations of the observatory the transit of mercury on may 6. (no. 14). 1878 abstract of lecture delivered at the observatory cockermouth on "the interior of the (no. 14). earth." 1978 june 1 report of the astronomer royal to the board of visitors. 1878 july 1 remarks on the measurement of the the observatory photographs taken in the transit of (no. 15). venus observations. 1878 july 13 on the variable star r. scuti: the observatory distortion in the photo-heliograph. (no. 16). 1878 remarks on mr gill's heliometric the observatory observations of mars. (no. 20). 1878 dec. note on a determination of the mass r. astr. soc. of mars, and reference to his own (month. not.) determination in 1828. also note on the conjunction of mars and saturn, 1879, june 30. 1879 jan. 1 on the remarkable conjunction of the observatory the planets mars and saturn which (no. 21). will occur on 1879, june 30. 1879 feb. 15 on the names "cabul" and "malek." athenaeum 1879 feb. 25 on faggot votes in cornwall in 1828. athenaeum 1879 mar. 13 letter on the examination papers for the smith's prizes. 1879 apr. 7 drafts of resolutions proposed concerning sadler's notes on the late admiral smyth's "cycle of celestial objects." 1879 june 1 letter to le verrier, dated 1875, the observatory feb. 5, in support of the method (no. 26). of least squares. 1879 june 1 remarks in debate on sadler's the observatory "notes" above-mentioned. (no. 26). 1879 june 7 report of the astronomer royal to the board of visitors. 1879 july 29 index to the records of occasional r. astr. soc. observations and calculations made (month. not. at the royal observatory, greenwich, supplementary.) and to other miscellaneous papers connected with that institution. 1879 biography of g. b. airy (perhaps corrected by himself) in french, published at geneva. 1879 sept. on the construction and use of a phil. mag. scale for gauging cylindrical measures of capacity. 1880 on the theoretical value of the the observatory acceleration of the moon's mean (no. 37). motion. 1880 on the secular acceleration of the observatory the moon--additional note. (no. 37). 1880 apr. 27 memoranda for the commission appointed to consider the tay bridge casualty. 1880 apr. on the theoretical value of the r. astr. soc. acceleration of the moon's mean (month. not.) motion in longitude produced by the change of eccentricity of the earth's orbit. 1880 may on the preparations to be made for r. astr. soc. observation of the transit of venus (month. not.) 1882, dec. 6. 1880 on the present proximity of jupiter the observatory to the earth, and on the intervals of (no. 42). recurrence of the same phaenomena. 1880 june 5 report of the astronomer royal to the board of visitors. 1880 sept. 4 on the _e muet_ in french. athenaeum. 1880 sept. 4 excursions in the keswick keswick district. guardian. 1880 dec. 1 description of flamsteed's the observatory equatoreal sextant, and remarks on (no. 44). graham. 1880 addition to a paper entitled "on r. astr. soc. the theoretical value of the moon's (month. not. mean motion in longitude," &c. supplementary.) 1881 mar. effect on the moon's movement in r. astr. soc. latitude, produced by the slow (month. not.) change of position of the plane of the ecliptic. 1881 june 4 report of the astronomer royal to the board of visitors. 1881 logarithms of the values of all inst. c. e. vulgar fractions with numerator and (minutes.) denominator not exceeding 100: arranged in order of magnitude. 1881 july 6 a new method of clearing the lunar distance.--admiralty. 1881 aug. 4 on a systematic interruption in the order phil. mag. of numerical values of vulgar fractions, when arranged in a series of consecutive magnitudes. 1882 sept. 15 monthly means of the highest and r. soc. (proc.) lowest diurnal temperatures of the water of the thames, and comparison with the corresponding temperatures of the air at the royal observatory, greenwich. 1882 oct. 19 on the proposed forth bridge. nature. 1882 dec. 7 on the proposed forth bridge. nature. 1883 jan. 21 on the ossianic poems. athenaeum. 1883 mar. 12 on the proposed braithwaite and daily news. buttermere railway. times. standard. 1883 apr. 28 memorandum on the progress of the numerical lunar theory, addressed to the board of visitors of the royal observatory, greenwich. 1883 letter on the apparent inequality in the the observatory mean motion of the moon. (no. 74). 1883 aug. 18 on a singular morning dream. nature. 1883 sept. 10 power of organization of the common nature. mouse. 1883 nov. 17 on chepstow railway bridge, with general nature. remarks suggested by that structure. 1884 mar. 8 on the erroneous usage of the term athenaeum. "arterial drainage." 1884 on the comparison of reversible and the observatory non-reversible transit instruments. (no. 85). 1884 nov. 10 on an obscure passage in the koran. nature. (?) 1885 may 28 an incident in the history of trinity athenaeum. college, cambridge. 1885 june 8 incident no. 2 in the history of trinity athenaeum. college, cambridge. 1885 nov. 26 results deduced from the measure of phil. trans. terrestrial magnetic force in the horizontal plane, at the royal observatory, greenwich, from 1841 to 1876. 1886 apr. 6 integer members of the first centenary nature. satisfying the equation aâ² = bâ² + câ². 1887 feb. 12 on the earlier tripos of the university of nature. (?) cambridge: in mss. 1887 apr. 14 on the establishment of the roman dominion nature. in south-east britain. 1887 july 23 on a special algebraic function, and its camb. phil. soc. application to the solution of (?) some equations: in mss. books written by g. b. airy. mathematical tracts on physical astronomy, the figure of the earth, precession and nutation, and the calculus of variations. this was published in 1826. in a 2nd edition published in 1831 the undulatory theory of optics was added to the above list. four editions of this work have been published, the last in 1858. the undulatory theory of optics was published separately in 1877. gravitation: an elementary explanation of the principal perturbations in the solar system. written for the penny cyclopaedia, and published previously as a book in 1834. there was a 2nd edition in 1884. trigonometry. this was written for the encyclopaedia metropolitana about 1825, and was published as a separate book in 1855 under the title of "a treatise on trigonometry." six lectures on astronomy delivered at the meetings of the friends of the ipswich museum at the temperance hall, ipswich, in the month of march 1848. these lectures under the above title, and that of "popular astronomy, a series of lectures," have run through twelve editions. on the algebraical and numerical theory of errors of observations and the combination of observations, 1st edition in 1861, 2nd in 1875, 3rd in 1879. essays on the invasion of britain by julius caesar; the invasion of britain by plautius, and by claudius caesar; the early military policy of the romans in britain; the battle of hastings, with correspondence. collected and printed for private distribution in 1865. an elementary treatise on partial differential equations. 1866. on sound and atmospheric vibrations, with the mathematical elements of music. the 1st edition in 1868, the 2nd in 1871. a treatise on magnetism, published in 1870. notes on the earlier hebrew scriptures, published in 1876. numerical lunar theory, published in 1886. index. accidents (see also illnesses) accounts acts and opponencies adams, prof. j.c. adams, john quincey agrarian fires aiken airy, william, father of g.b.a. airy, ann, mother of g.b.a. airy, william, brother of g.b.a., and basil r. airy, his son airy, arthur, brother of g.b.a. airy, elizabeth, sister of g.b.a. airy, richarda, wife of g.b.a. airy, children of g.b.a. george richard elizabeth arthur wilfrid hubert hilda christabel annot osmund allsop alnwick altazimuth instrument althorp, lord american observatories american method of recording observations (see galvanic registration) ampã¨re ancient eclipses anderson, lessee of harton colliery anemometer (see meteorology) anniversary parties antiquarian researches and notes arago architecture (see cathedrals, &c.) astronomical society (see royal astr. soc.) astronomische gesellschaft athenaeum newspaper athenaeum club atkinson, senior wrangler 1821 atlantic cable atmospheric railway (see railways) auckland, lord aurora borealis australian observatories (see also observatories) auwers, dr babbage, charles baily, francis bakhuysen, of leyden balance (public balance) baldock, commander baldrey, assistant banks, optician baring, sir t. barlow, prof. barlow, w.h. barnard, proctor barnes, miss barnes, gorell barometers barry, sir c. barton, bernard baxter, secretary to the admiralty beacons, floating beaufort, captain beaumont's observatory bedingfield, pupil bell scholarships (see examinations) bessell, astronomer biddell, arthur, uncle of g.b.a. biddell, george, uncle of g.b.a. biddell, william, uncle of g.b.a. biddell, george arthur, son of arthur biddell biographical notes bissett, pupil blackwood, captain blakesley, canon blasting bliss's observations blomfield, g.b., pupil bloomfield, lord board of longitude boileau bond, g.p. books, written by g.b.a., appendix book society, cambr. bosanquet bouch, t. civ. eng. boundary of canada (see canada) bouvard, e. bowstead bradley's observations brazil, emperor of breakwaters (see harbours) breen, assistant brewster, sir d. bridges brinkley, dr bristow, miss britannia bridge (see bridges) brooke, charles british association brougham, lord browne, g.a. brunel, civ. eng. buck buckland, dr buckle, pupil burgoyne, sir j. burlington, lord burton busts (see portraits) calculating machines calvert cambridge observatory: assistants instruments printed observations general cambridge university cambridge observatory, u.s.a. canada boundary cankrein, pupil canning, lord cape of good hope, observatory and survey carpenter, assistant cartmell, dr case catalogues of stars (see stars) cathedrals and churches catton cavendish experiment cayley, prof. challis, prof. chalmers, dr cherbourg (see harbours) chesil bank childers childers, first lord of admiralty christchurch christie, prof. christie, astronomer royal chronographic barrel (see galvanic registration) chronometers churches (see cathedrals) church service cincinnati observatory clarendon, lord clark, latimer clarkson, thomas, and mrs clarkson cleasby, pupil clegg clinton, pupil clocks cockburn, sir g. coinage (see decimal coinage) colby, col. colchester colenso, bishop college hall collorado, count colonial observatories (see observatories) comets commissions compass corrections cookson, dr cooper, pupil cooper's telescope (see telescopes) copying press corbaux, miss corryvreckan whirlpool courtney, rev. j. cowper, first commissioner of works crawford, pupil criswick, assistant cropley, crosse, rev. e. cubitt, sir w. daguerrotypes dalhousie, lord davy, sir humphrey davy, dr daynou, lieut. deal time ball de berg decimal coinage and decimal subdividing dee navigation (see rivers) degrees (see also orders and elections to societies) deighton, publisher de la rive de la rue de launay deluge, the de morgan, a. denison, e.b. denison, sir w. denison, h. denmark, king of dent, clockmaker dent-dale devonshire, duke of dobbs, pupil dobree, lecturer docks (see harbours) dolcoath experiments dollond, instrument maker drainage drinkwater, bethune double-image micrometer douglas, sir h. dover (see harbours) dublin professorship (see professorships) dublin observatory (see observatories) duã«, baron dundas, admiral dundonald, lord dunkin, assistant dunlop, astronomer durham observatory earnshaw earth currents eastons, manufacturers eclipses (see also ancient eclipses) edinburgh observatory edmonston, dr education (see university education) egyptian astronomical tablets elections to societies, &c. (see also degrees and orders) electricity, atmospheric ellenborough, lord ellis, w., assistant elphinstone encke and encke's comet encyclopaedia metropolitana engines (see steam-engines) equatoreal, large estcourt, col. evans, lecturer examinations exhibitions and prizes exodus of the israelites eye, defects of eye, estate at fallows, astronomer faraday farish farr fellowship field fisher fishmongers' company fletcher, isaac, m.p. floating island, derwentwater fluid telescope, barlow's foley forbes, prof. j.d. foster, messrs fox, alfred freedom of the city of london freemantle, sir t. french, dr friends, personal friends at cambridge fries, prof. galbraith galle galvanic communication, time-signals, clocks, and registration (see also earth currents) gambard gas act gauss gautier geodesy geology geological society germany gibson, pupil gilbert, messrs gilbert, davies gill, astronomer gladstone, w.e. glaisher, assistant glasgow observatory gordon gosset goulburn, chancellor of the exchequer gould, dr b.a. goussel graduation of circles grant, of glenmoriston great circle sailing (see navigation) great eastern (see ships) great exhibition great gable green, commander u.s.n. greenwich greenwich observatory, before his appointment as astronomer royal greenwich observatory: appointment as astronomer royal, and subsequently as visitor buildings and grounds in, instruments assistants computations papers and manuscripts (arrangement of) estimates printed observations visitations and reports general gresswell groombridge's catalogue (see stars) guest, caius college haarlem hall, col. halley and halley's comet hamilton hamilton, sir w.r. hamilton, admiral hansard hansen, prof. hansteen harbours harcourt, rev. w. vernon hartnup, astronomer harton colliery experiments haviland, dr hawkes, trinity college hebrew scriptures heliograph hencke henderson, astronomer henslow, prof. herbert, g. hereford herschel, sir john herschel, miss caroline herschel, col. j. hervey, pupil higman, tutor, trinity college hilgard, u.s.a. himalaya expedition hind, moderator hind, superintendent nautical almanac hopkins hovenden, pupil hudson huggins, dr humboldt, baron a. humphreys hussey, dr hustler, tutor, trinity college hyde parker, admiral hygrometers ibbotson, pupil iliff illnesses inequality, venus and earth inglis, sir r. institut de france institution of civil engineers inverness, northern institution of ipswich lectures ireland, notes of ivory jackson jackson, john james, sir h. janus (see steam-engines) jarrow (see harbours) jeffries jerrard, dr jervis, major jeune, dr, v.c. of oxford johnson, capt. johnson, astronomer jones, instrument-makers jones, r. journeys: scotland and cumberland; swansea; derbyshire, &c.; wales; keswick, &c.; cornwall, &c.; orlã©ans; lake district, &c.; continent, observatories, &c.; cornwall, &c.; derbyshire; oxford &c.; cumberland; ireland; scotland; derbyshire, &c.; cumberland, &c.; ireland; kent; s. wales; luddington and yorkshire; border of scotland; s. wales; cumberland and yorkshire; south of ireland; ireland; france; cornwall; germany; petersburg, &c.; ireland; shetland; scotland; sweden; madeira; cumberland; cumberland; oban, &c.; italy and sicily; west highlands; switzerland; central france; spain (eclipse); cumberland; west highlands; west highlands; cumberland; norway; cumberland; switzerland; cumberland; cumberland; cumberland; scotland; scotland; n. of scotland; ireland; scotland, &c.; cumberland; cumberland; cumberland; cumberland; s. wales; cumberland 358; cumberland julius caesar, landing of jupiter (see planets) keeling kennedy king, joshua kingstown knight, publisher knighthood, offers of lagarde laing landman, engineer langton lardner, dr lassell, and lassell's telescope latitude determinations lax, prof. lectures: college professorial miscellaneous lefevre, j.g.s. leitch, dr le verrier lewis, h. lewis, sir g.c. lightfoot, rev. dr lighthouses lightning lillingstone lindsay, lord listing, prof. liverpool observatory livingstone, dr lloyd, dr lloyd, prof. lockyer lodge london university london, freedom of the city long vacations, with pupils longitude determinations longitude, board of (see board of longitude) lowe, chancellor of the exchequer lubbock, sir john lucas (computer) lucasian professorship (see professorships) lunar reductions lunar theory and tables (see also numerical lunar theory) lyndhurst, lord lyons, sir e. macaulay, t.b. macdonnell, dr maclean, of loch buy maclear, astronomer madras observatory 101 magnetic observatory and magnetism (see also meteorology, compass corrections, and earth currents) main, robert maine boundary (see canada) maiden, prof. malkin malta man-engines (see mines) manuscripts (see papers) mars (see planets) marshman, pupil marth, a. martin, trin. coll. maskelyne, astronomer mason mathematical investigations (see also appendix "printed papers") mathematical tracts mathematical subjects in maudslays and field may, ransomes and may medals melbourne university melville, lord mercury (see planets) merivale, dr meteorology meteors middleton, sir w. milaud military researches miller, prof. mines minto, lord mitchell, astronomer mitchell miss molesworth, sir w. monteagle, lord monument in playford church moon: observations of theory and tables of (see lunar theory and tables) reductions of observations of (see lunar reductions) mass of morpeth, lord morton, pierce, pupil murchison, sir r. murray, publisher musgrave, charles musgrave, t. archbishop myers nasmyth nautical almanac navigation neate, pupil neptune and uranus newall newcombe, prof. new forest northampton, lord northumberland telescope numerical lunar theory observatories: see american, australian, beaumont's, cambridge, cambridge u.s.a., cape of good hope, cincinnati, colonial, dublin, durham, edinburgh, glasgow, greenwich, liverpool, madras, oxford, paris, paramatta, pulkowa, st helena, williamstown occultations o'connell ogilby, pupil oppolzer, prof. opponencies (see acts and opponencies) optics orders (see also degrees and elections to societies) ouvaroff, count oxford observatory oxford, miscellaneous packington, sir j. palmerston, lord papers (see appendix "printed papers") papers, arrangement of parachute, fall of parallax (see sun) paramatta observatory parker, charles parker, vice-chancellor paris, dr paris observatory paris exhibition parliamentary elections pasley paul peacock, george pearson, dr peel, sir robert pendulum investigations and experiments penny cyclopaedia pension pentland percy, bishop personal sketch philosophical society, cambridge philpott, dr photography piers (see harbours) pinheiro, lieut. pipon, lieut. plana, astronomer planetary influences planetary reductions planets (see also transits of venus) plantamour playford plumian professorship (see professorships) pocket-books for observations pogson, astronomer pond, astronomer portlock, capt. portraits, busts, &c. post office, (clocks, &c.) post office, stamps and envelopes pouillet prince albert pritchard, rev. c. prizes (see exhibitions) probable errors professorships: dublin; lucasian; plumian public schools commission pulkowa observatory pupils: bedingfield; bissett; blomfield; buckle; cankrein; cleasby; clinton; cooper; crawford; dobbs; gibson; guest; hervey; hovenden; ibbotson; lewis; marshman; morton; neate; ogilby; parker; rosser; smith; tinkler; tottenham; turner; wigram; williamson pym, engineer queen, h.m. the queen, quã©roualle, mdlle de quetelet railways, near observatory railway gauge commission railways, miscellaneous rain (see meteorology) rainbows ransomes, also ransomes and may 17, reach reflex zenith tube religious tests and views repsold rhodes richardson, assistant rigaud, prof. rivers robinson, dr robinson, capt. rogers, rev. rogers, school assistant romilly, lord ronalds rose, rev. h.j. rosse, lord, and rosse's telescope rosser, pupil rothery rothman round down cliff, blasting of rouse, rev. r.c. m. routh, dr e.j. royal astronomical society (see also appendix "printed papers") royal exchange clock royal institution royal society (see also appendix "printed papers") royal society of edinburgh rã¼ncker, paramatta rã¼ncker rundell rusby russell, lord john sabine, col. sadler, h. saint helena observatory samuda saturn (see planets) saunders, g.w. by saw-mills (see ship timbers) schehallien, mountain scholarship scholefield schumacher scientific manual scoop-wheels scoresby, dr scriptural researches (see hebrew scriptures) sedgwick, adam selwyn, prof. senate house examination (see also university education) sewers commission sheepshanks, rev. richard, and miss sheepshanks sheepshanks fund and scholarship shepherd, clock-maker ship-timbers, machinery for sawing, shirreff, capt. simmons simms, f.w. simms (see troughton and simms) skeleton forms sly, draughtsman smith, rev. r. smith, father-in-law of g.b.a., and mrs smith, smith, the misses smith, sisters of richarda airy, susanna; elizabeth; georgiana; florence; caroline smith, archibald smith, m., pupil smith's prizes smyth, capt. w.h. smyth, piazzi societies, &c., elections to (see elections) solar eclipses (see eclipses) solar inequality (see sun) solar system (see sun) solar tables (see sun) south, sir james south's telescope south-eastern railway southampton southey (poet) spectroscopy spottiswoode spring-rice, lord monteagle standards of length and weight, and standards commission stars start point steam-engines stephenson, george stephenson, robert steventon stewart, prof. balfour stjerneld, baron stokes, prof. stone, astronomer stratford, lieut. stroganoff, count strutt, lord belper strutt, jedediah struve, otto stuart, prof. j. sun: miscellaneous parallax of (see also transits of venus) eclipses of (see eclipses) inequality, venus and earth tables of surveys (see trigonometrical surveys) sussex, duke of, sutcliffe sutcliffe, miss sydney university sylvester sweden, king of tate taylor, architect taylor, first assistant to pond, taylor, h. telegraphs (see galvanic communications) telescopes (see also cambridge observatory instruments, and greenwich observatory instruments) teneriffe experiment thames, the river, theology (see also hebrew scriptures and colenso) thermometers thermo-multiplier thirlwall, bishop thomas, assistant thompson, master trin. coll. thomson, sir w. tidal harbour commission tides, time-signals and time (see also galvanic communication, &c.) time balls (see time signals) tinkler, pupil tottenham, pupil traill, dr transit circle, transits of venus trigonometrical survey trinity college, cambridge trinity house tripos examination (see senate-house examination) troughton and simms tulley, optician tupman, capt turner, pupil turton, prof. tutorship ulrich, j.g. universities (see cambridge, dublin, edinburgh, london, melbourne, oxford, sydney) university education (see also smith's prizes and senate-house examination) university press, uranus (see neptune) valencia (see also longitude determinations) venus (see planets, and transits of venus) venus and earth inequality (see inequality) vernon harcourt (see harcourt) vetch, capt. vibrations of ground vignoles, c.b., engineer vulliamy, clockmaker wales, prince of walker, byatt walker, james, engineer walker, sydney, warburton, h. washington, capt. water telescope (see also fluid telescope) watson waves (see tides) webster, m.p. for aberdeen western westminster clock (see also clocks) wexford harbour (see harbours) wheatstone whewell, william white house, the, wigram, pupil williams, john williamson, pupil williamstown observatory wilson, prof. winchester winds (see meteorology) winning wood, sir charles wood, dr woodbridge, suffolk woodhouse, prof. woolwich academy (see examinations) wordsworth, dr, master of trin. coll. wordsworth, poet wrede, baron wynter, vice-chancellor, oxford yolland, col. york cathedral young, dr 