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diff --git a/old/64649-0.txt b/old/64649-0.txt deleted file mode 100644 index 81c76bf..0000000 --- a/old/64649-0.txt +++ /dev/null @@ -1,6909 +0,0 @@ -The Project Gutenberg eBook of The Herschels and Modern Astronomy, by Agnes -Mary Clerke - -This eBook is for the use of anyone anywhere in the United States and -most other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms -of the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you -will have to check the laws of the country where you are located before -using this eBook. - -Title: The Herschels and Modern Astronomy - -Author: Agnes Mary Clerke - -Release Date: February 27, 2021 [eBook #64649] - -Language: English - -Character set encoding: UTF-8 - -Produced by: Fay Dunn, Charlie Howard, and the Online Distributed - Proofreading Team at https://www.pgdp.net (This file was - produced from images generously made available by The Internet - Archive) - -*** START OF THE PROJECT GUTENBERG EBOOK THE HERSCHELS AND MODERN -ASTRONOMY *** - - - - -THE CENTURY SCIENCE SERIES. - - EDITED BY SIR HENRY E. ROSCOE, D.C.L., LL.D., F.R.S. - - - THE HERSCHELS - AND - _MODERN ASTRONOMY_ - - - - -The Century Science Series. - -EDITED BY - -SIR HENRY E. ROSCOE, D.C.L., F.R.S., M.P. - - - =John Dalton and the Rise of Modern Chemistry.= - By Sir HENRY E. ROSCOE, F.R.S. - - =Major Rennell, F.R.S., and the Rise of English Geography.= - By CLEMENTS R. MARKHAM, C.B., F.R.S., President of the Royal - Geographical Society. - - =The Herschels and Modern Astronomy.= - By Miss AGNES M. CLERKE, Author of “A Popular History of - Astronomy during the 19th Century,” &c. - - - _In Preparation._ - - =Justus von Liebig: his Life and Work.= - By W. A. SHENSTONE, Science Master in Clifton College. - - =Michael Faraday: his Life and Work.= - By Professor SILVANUS P. THOMPSON, F.R.S. - - =Clerk Maxwell and Modern Physics.= - By R. T. GLAZEBROOK, F.R.S., Fellow of Trinity College, - Cambridge. - - =Charles Lyell: his Life and Work.= - By Rev. Professor T. G. BONNEY, F.R.S. - - =Humphry Davy.= - By T. E. THORPE, F.R.S., Principal Chemist of the Government - Laboratories. - - =Pasteur: his Life and Work.= - By ARMAND RUFFER, Director of the British Institute of - Preventive Medicine. - - =Charles Darwin and the Origin of Species.= - By EDWARD B. POULTON, M.A., F.R.S., Hope Professor of Zoology - in the University of Oxford. - - =Hermann von Helmholtz.= - By A. W. RÜCKER, F.R.S., Professor of Physics in the Royal - College of Science, London. - - -CASSELL & COMPANY, LIMITED, _London; Paris & Melbourne_. - - - - -[Illustration: SIR WILLIAM HERSCHEL. - -_Ætat. 50._ - -(_From Abbott’s painting in the National Portrait Gallery._)] - - - - - _THE CENTURY SCIENCE SERIES._ - - THE HERSCHELS - AND - _MODERN ASTRONOMY_ - - BY - AGNES M. CLERKE - - AUTHOR OF - “A POPULAR HISTORY OF ASTRONOMY DURING THE 19TH CENTURY,” - “THE SYSTEM OF THE STARS,” ETC. - - - CASSELL AND COMPANY, LIMITED - _LONDON, PARIS & MELBOURNE_ - 1895 - - ALL RIGHTS RESERVED - -[Illustration] - - - - -PREFACE. - - -The chief authority for the Life of Sir William Herschel is Mrs. John -Herschel’s “Memoir of Caroline Herschel” (London, 1876). It embodies -Caroline’s Journals and Recollections, the accuracy of which is -above suspicion. William himself, indeed, referred to her for dates -connected with his early life. The collateral sources of information -are few and meagre; they yield mere gleanings, yet gleanings worth -collecting. Professor E. S. Holden has had recourse to many of them -for his excellent little monograph entitled “Herschel, his Life and -Works” (London, 1881), which is usefully supplemented by “A Synopsis -of the Scientific Writings of Sir William Herschel,” prepared by the -same author with the aid of Professor Hastings. It made part of the -Smithsonian Report for 1880, and was printed separately at Washington -in 1881. But the wonderful series of papers it summarises have still -to be sought, one by one, by those desiring to study them effectually, -in the various volumes of the _Philosophical Transactions_ in which -they originally appeared. Their collection and republication is, -nevertheless, a recognised desideratum, and would fill a conspicuous -gap in scientific literature. - -Sir John Herschel’s life has yet to be written. The published materials -for it are scanty, although they have been reinforced by the inclusion -in the late Mr. Graves’s “Life of Sir William Rowan Hamilton” (Dublin, -1882–9) of his correspondence with that remarkable man. The present -writer has, however, been favoured by the late Miss Herschel, and by -Sir William J. Herschel, with the perusal of a considerable number of -Sir John Herschel’s, as well as of Sir William’s, manuscript letters. -She also gratefully acknowledges the kind help afforded to her by Lady -Gordon and Miss Herschel in connection with the portraits reproduced -in this volume. For detailed bibliographical references, the articles -on Sir John, Sir William, and Caroline Herschel, in the “Dictionary of -National Biography,” may be consulted. - - - - -CONTENTS. - - - PAGE - CHAPTER - I.--EARLY LIFE OF WILLIAM HERSCHEL 9 - - II.--THE KING’S ASTRONOMER 32 - - III.--THE EXPLORER OF THE HEAVENS 53 - - IV.--HERSCHEL’S SPECIAL INVESTIGATIONS 75 - - V.--THE INFLUENCE OF HERSCHEL’S CAREER ON MODERN ASTRONOMY 98 - - VI.--CAROLINE HERSCHEL 115 - - VII.--SIR JOHN HERSCHEL AT CAMBRIDGE AND SLOUGH 142 - - VIII.--EXPEDITION TO THE CAPE 162 - - IX.--LIFE AT COLLINGWOOD 183 - - X.--WRITINGS AND EXPERIMENTAL INVESTIGATIONS 203 - - - - -ILLUSTRATIONS. - - - PAGE - PORTRAIT OF SIR WILLIAM HERSCHEL _Frontispiece_ - - PORTRAIT OF CAROLINE HERSCHEL 115 - - PORTRAIT OF SIR JOHN HERSCHEL 142 - - - - -THE HERSCHELS - -AND - -MODERN ASTRONOMY. - - - - -CHAPTER I. - -EARLY LIFE OF WILLIAM HERSCHEL. - - -William Herschel was descended from one of three brothers, whose -Lutheran opinions made it expedient for them to quit Moravia early -in the seventeenth century. Hans Herschel thereupon settled as a -brewer at Pirna, in Saxony; his son Abraham rose to some repute as -a landscape-gardener in the royal service at Dresden; and Abraham’s -youngest son, Isaac, brought into the world with him, in 1707, an -irresistible instinct and aptitude for music. Having studied at Berlin, -he made his way in 1731 to Hanover, where he was immediately appointed -oboist in the band of the Hanoverian Guard. A year later he married -Anna Ilse Moritzen, by whom he had ten children. The fourth of these, -Frederick William, known to fame as _William_ Herschel, was born -November 15th, 1738. - -His brilliant faculties quickly displayed themselves. At the -garrison-school he easily distanced his brother Jacob, his senior -by four years, and learned besides, privately, whatever French and -mathematics the master could teach him. He showed also a pronounced -talent for music, and was already, at fourteen, a proficient on the -hautboy and violin. In this direction lay his manifest destiny. His -father was now bandmaster of the Guard; he was poor, and had no other -provision to give his sons than to train them in his own art; and -thus William, driven by necessity to become self-supporting while -still a boy, entered the band as oboist in 1753. They were a family -of musicians. Of the six who reached maturity, only Mrs. Griesbach, -the elder daughter, gave no sign of personally owning a share in the -common gift, which descended, nevertheless, to her five sons, all noted -performers on sundry instruments. - -William Herschel accompanied his regiment to England in 1755, with his -father and elder brother. He returned a year later, bringing with him -a copy of Locke “On the Human Understanding,” upon which he had spent -the whole of his small savings. Two of the three volumes thus acquired -were recovered by his sister after seventy years, and transmitted to -his son. The breaking-out of the Seven Years’ War proved decisive as to -his future life. Campaigning hardships visibly told upon his health; -his parents resolved, at all hazards, to rescue him from them; and -accordingly, after the disaster at Hastenbeck, July 26th, 1757, they -surreptitiously shipped him off to England. By this adventure, since he -was in the military service of the Elector of Hanover, George III. of -England, he incurred the penalties of desertion; but they were never -exacted, and were remitted by the King himself in 1782. - -William Herschel was in his nineteenth year when he landed at Dover -with a French crown-piece in his pocket. Necessity or prudence kept -him for some time obscure; and we next hear of him as having played a -solo on the violin at one of Barbandt’s concerts in London, February -15th, 1760. In the same year he was engaged by the Earl of Darlington -to train the band of the Durham Militia, when his shining qualities -brought him to the front. The officers of the regiment looked with -astonishment on the phenomenal young German who had dropped among them -from some cloudy region; who spoke English perfectly, played like a -virtuoso, and possessed a curious stock of varied knowledge. Their -account of him at a mess-dinner excited the curiosity of Dr. Miller, -organist and historian of Doncaster, who, having heard him perform a -violin solo by Giardini, fell into a rapture, and invited him on the -spot to live with him. - -He left nothing undone for the advancement of his _protégé_; procured -for him tuitions and leading concert engagements; and encouraged him, -in 1765, to compete for the post of organist at Halifax. Herschel’s -special qualifications were small; his chief rival, Dr. Wainwright, was -a skilled player, and at the trial performance evoked much applause -by his brilliant execution. Only the builder of the organ, an odd -old German named Schnetzler, showed dissatisfaction, exclaiming: -“He run about the keys like one cat; he gif my pipes no time for to -shpeak.” Then Herschel mounted the loft, and the church was filled -with a majestic volume of sound, under cover of which a stately melody -made itself heard. The “Old Hundredth” followed, with equal effect. -Schnetzler was beside himself with delight. “I vil luf dis man,” he -cried, “because he git my pipes time for to shpeak.” Herschel had -virtually provided himself with four hands. A pair of leaden weights -brought in his pocket served to keep down two keys an octave apart, -while he improvised a slow air to suit the continuous bass thus -mechanically supplied. The artifice secured him the victory. - -This anecdote is certainly authentic. It is related by Dr. Miller from -personal knowledge. Nor is it inconsistent with a story told by Joah -Bates, of King’s College, Cambridge, a passionate lover of music. -Repairing to Halifax, his native place, to conduct the “Messiah” at -the opening of a new organ, he was accosted in the church by a young -man, who asked for an opportunity of practising on it. Although as yet, -he said, unacquainted with the instrument, he aspired to the place of -organist; and the absolute certitude of his manner so impressed Bates -that he not only granted his request, but became his warm patron. -The young man’s name was William Herschel. We hear, further, on Dr. -Burney’s authority, that he played first violin in Bates’s orchestra. - -But the tide of his fortunes was flowing, and he knew how to “take it -at the flood.” Early in 1766 he removed to Bath as oboist in Linley’s -celebrated orchestra, which played daily in the Pump Room to enliven -the parade of blushing damsels and ruffling gallants pictured to our -fancy in Miss Austen’s novels. Bath was then what Beau Nash had made -it--the very focus of polite society. Turbans nodded over cards; gigs -threaded their way along Union Passage; Cheap Street was blocked with -vehicles; the Lower Rooms witnessed the nightly evolutions of the -country-dance; the Grove, as Doran reminds us, was brilliant with -beauty, coquelicot ribbons, smart pelisses, laced coats, and ninepins. -The feat of “tipping all nine for a guinea” was frequently performed; -and further excitement might be had by merely plucking some lampoons -from the trees, which seemed to bear them as their natural fruit. -Music, too, was in high vogue. The theatres were thronged; and Miss -Linley’s exquisite voice was still heard in the concert-halls. - -On the 4th of October, 1767, the new Octagon Chapel was opened for -service, with Herschel as organist. How it was that he obtained this -“agreeable and lucrative situation” we are ignorant; but he had that -singular capacity for distinction which explains everything. The -Octagon Chapel became a centre of fashionable attraction, and he soon -found himself lifted on the wave of public favour. Pupils of high -rank thronged to him, and his lessons often mounted to thirty-five a -week. He composed anthems, psalm-tunes, even full services for his -assiduously-trained choir. His family were made sharers in his success. -He secured a post in Linley’s orchestra for his younger brother -Alexander, in 1771; and he himself fetched his sister Caroline to Bath -in 1772. Both were of very considerable help to him in his musical and -other enterprises, the latter of which gradually gained ground over the -former. - -Music was never everything to William Herschel. He cultivated it with -ardour; composed with facility in the prevalent graceful Italian style; -possessed a keen appreciation and perfect taste. But a musical career, -however brilliant, did not satisfy him. The inner promptings of genius -told him to look beyond. The first thirty-five years of his life -were thus spent in diligently preparing to respond to an undeclared -vocation. Nothing diverted him from his purpose of self-improvement. -At first, he aimed chiefly at mastering the knowledge connected -with his profession. With a view to the theory of music, “I applied -myself early,” he said, in a slight autobiographical sketch sent to -Lichtenberg at Göttingen, “to all the branches of the mathematics, -algebra, conic sections, fluxions, etc. Contracting thereby an -insatiable desire for knowledge in general, I extended my application -to languages--French, Italian, Latin, English--and determined to devote -myself entirely to the pursuit of knowledge, in which I resolved to -place all my future enjoyment and felicity. This resolution I have -never had occasion to change.” At Bath, in the midst of engrossing -musical occupations, his zeal for study grew only the more intense. -After fourteen or sixteen hours of teaching, he would “unbend his mind” -by plunging into Maclaurin’s “Fluxions,” or retire to rest with a basin -of milk, Smith’s “Opticks,” and Ferguson’s “Astronomy.” He had no -sooner fallen under the spell of this last science than he “resolved to -take nothing upon trust, but to see with my own eyes all that other men -had seen before.” - -He hired, to begin with, a small reflector; but what it showed him -merely whetted his curiosity. And the price of a considerably larger -instrument proved to be more than he could afford to pay. Whereupon -he took the momentous resolution of being, for the future, his own -optician. This was in 1772. He at first tried fitting lenses into -pasteboard tubes, with the poor results that can be imagined. Then he -bought from a Quaker, who had dabbled in that line, the discarded -rubbish of his tools, patterns, polishers, and abortive mirrors; and in -June, 1773, when fine folk had mostly deserted Bath for summer resorts, -work was begun in earnest. The house was turned topsy-turvy; the two -brothers attacked the novel enterprise with boyish glee. Alexander, -a born mechanician, set up a huge lathe in one of the bedrooms; a -cabinet-maker was installed in the drawing-room; Caroline, in spite of -secret dismay at such unruly proceedings, lent a hand, and kept meals -going; William directed, inspired, toiled, with the ardour of a man -who had staked his life on the issue. Meanwhile, music could not be -neglected. Practising and choir-training went on; novelties for the -ensuing season were prepared; compositions written, and parts copied. -Then the winter brought the usual round of tuitions and performances, -while all the time mirrors were being ground and polished, tried and -rejected, without intermission. At last, after _two hundred_ failures, -a tolerable reflecting telescope was produced, about five inches in -aperture, and of five and a half feet focal length. The outcome may -seem small for so great an expenditure of pains; but those two hundred -failures made the Octagon Chapel organist an expert, unapproached -and unapproachable, in the construction of specula. With his new -instrument, on March 4th, 1774, he observed the Nebula in Orion; and a -record of this beginning of his astronomical work is still preserved by -the Royal Society. - -William Herschel was now, as to age, _in mezzo cammin_. He had numbered -just so many years as had Dante when he began the “Divina Commedia.” -But he had not, like Dante, been thrown off the rails of life. The -rush of a successful professional career was irresistibly carrying him -along. Almost any other man would have had all his faculties absorbed -in it. Herschel’s were only stimulated by the occupations which it -brought. Yet they were of a peculiarly absorbing nature. Music is -the most exclusive of arts. In turning aside, after half a lifetime -spent in its cultivation, to seek his ideal elsewhere, Herschel took -an unparalleled course. And his choice was final. Music was long his -pursuit, astronomy his pastime; a fortunate event enabled him to make -astronomy his pursuit, while keeping music for a pastime. - -Yet each demands a totally different kind of training, not only of -the intellect, but of the senses. From his earliest childhood William -Herschel’s nerves and brain had been specially educated to discriminate -impressions of sound, and his muscles to the peculiar agility needed -for their regulated and delicate production; while, up to the age of -thirty-five, he had used his eyes no more purposefully than other -people. The eye, nevertheless, requires cultivation as much as the ear. -“You must not expect to _see at sight_,” he told Alexander Aubert, of -Loam Pit Hill, in 1782. And he wrote to Sir William Watson: “Seeing is -in some respects an art which must be learnt. Many a night have I been -practising to see, and it would be strange if one did not acquire a -certain dexterity by such constant practice.” A critical observation, -he added, could no more be expected from a novice at the telescope than -a performance of one of Handel’s organ-fugues from a beginner in music. -In this difficult art of vision he rapidly became an adept. Taking into -account the full extent of his powers, the opinion has been expressed, -and can scarcely be contradicted, that he never had an equal. - -At midsummer, 1774, Herschel removed from No. 7, New King Street, to a -house situated near Walcot Turnpike, Bath. A grass-plot was attached -to the new residence, and it afforded convenient space for workshops. -For already he designed to “carry improvements in telescopes to their -utmost extent,” and “to leave no spot of the heavens unvisited.” An -unprecedented ambition! No son of Adam had ever before entertained -the like. To search into the recesses of space, to sound its depths, -to dredge up from them their shining contents, to classify these, to -investigate their nature, and trace their mutual relations, was what he -proposed to do, having first provided the requisite optical means. All -this in the intervals of professional toils, with no resources except -those supplied by his genius and ardour, with no experience beyond that -painfully gained during the progress of his gigantic task. - -Since the time of Huygens, no systematic attempt had been made to add -to the power of the telescope. For the study of the planetary surfaces, -upon which he and his contemporaries were mainly intent, such addition -was highly desirable. But Newton’s discovery profoundly modified the -aims of astronomers. Their essential business then became that of -perfecting the theories of the heavenly bodies. Whether or not they -moved in perfect accordance with the law of gravitation was the crucial -question of the time. Newton’s generalisation was on its trial. Now and -again it almost seemed as if about to fail. But difficulties arose only -to be overcome, and before the eighteenth century closed the superb -mechanism of the planetary system was elucidated. Working flexibly -under the control of a single dominant force, it was shown to possess a -self-righting power which secured its indefinite duration. Imperishable -as the temple of Poseidon, it might be swayed by disturbances, but -could not be overthrown. - -The two fundamental conclusions--that the Newtonian law is universally -valid, and that the solar system is a stable structure--were reached -by immense and sustained labours. Their establishment was due, in the -main, to the mathematical genius of Clairaut, D’Alembert, Lagrange, -and Laplace. But refined analysis demands refined data; hence the need -for increased accuracy of observation grew continually more urgent. -Attention was accordingly concentrated upon measuring, with the utmost -exactitude, the places at determinate epochs of the heavenly bodies. -The one thing needful was to learn the “when” and “where” of each of -them--that is, to obtain such information as the transit-instrument is -adapted to give. In this way the deviations of the moon and planets -from their calculated courses became known; and upon the basis of -these “errors” improved theories were built, then again compared with -corrected observations. - -For these ends, large telescopes would have been useless. They were -not, however, those that Herschel had in view. The _nature_ of the orbs -around us, not their motions, formed the subject of his inquiries, -with which modern descriptive astronomy virtually originated. He was, -moreover, the founder of sidereal astronomy. The stars had, until -his career began, received little _primary_ attention. They were -regarded and observed simply as reference-points by which to track the -movements of planets, comets, and the moon. Indispensable for fiducial -purposes, they almost escaped consideration for themselves. They were, -indeed, thought to lie beyond the reach of effective investigation. -Only the outbursts of temporary stars, and the fluctuations of two -or three periodical ones, had roused special interest, and seemed -deserving of particular inquiry. - -Of the dim objects called “nebulæ,” Halley had counted up half a -dozen in 1714; Lacaille compiled a list of forty-two at the Cape, -in 1752–55; and Messier published at Paris, in 1771, a catalogue of -forty-five, enlarged to one hundred and three in 1781. He tabulated, -only to rid himself of embarrassments from them. For he was _by trade_ -a comet-hunter, and, until he hit upon this expedient, had been much -harassed in its exercise by mistakes of identity. - -But Herschel did not merely “pick up;” he explored. This was what no -one before him had thought of doing. A “review of the heavens” was a -complete novelty. The magnificence of the idea, which was rooted in his -mind from the start, places him apart from, and above, all preceding -observers. - -To its effective execution telescopic development was essential. -The two projects of optical improvement and of sidereal scrutiny -went together. The skies could be fathomed, if at all, only by means -of light-collecting engines of unexampled power. Rays enfeebled by -distance should be rendered effective by concentration. Stratum after -stratum of bodies-- - - “Clusters and beds of worlds, and bee-like swarms - Of suns and starry streams,” - -previously unseen, and even unsuspected, might, by the strong focussing -of their feebly-surviving rays, be brought to human cognisance. The -contemplated “reviews” would then be complete just in proportion to the -grasp of the instrument used in making them. - -The first was scarcely more than a reconnaissance. It was made in -1775, with a small reflector of the Newtonian make.[A] Its upshot was -to impress him with the utter disproportion between his daring plans -and the means as yet at his disposal. Speculum-casting accordingly -recommenced with fresh vigour. Seven- and ten-foot mirrors were -succeeded by others of twelve, and even of twenty feet focal length. -The finishing of them was very laborious. It was at that time a manual -process, during the course of which the hands could not be removed from -the metal without injury to its figure. One stretch of such work lasted -sixteen hours, Miss Herschel meantime, “by way of keeping him alive,” -putting occasional morsels of food into the diligent polisher’s mouth. -His mode of procedure was to cast and finish many mirrors of each -sort; then to select the best by trial, and repolish the remainder. In -this manner he made, before 1781, “not less than 200 seven-foot, 150 -ten-foot, and about 80 twenty-foot mirrors, not to mention those of the -Gregorian form.” Repolishing operations were, moreover, accompanied -by constant improvements, so that each successive speculum tended to -surpass its predecessors. - - [A] In “Newtonian” telescopes the image formed by the large - speculum is obliquely reflected from a small plane mirror - to the side of the tube, where it is viewed with an - ordinary eye-piece. With a “Gregorian,” the observer looks - straight forward, the image being thrown back by a little - _concave_ mirror through a central perforation in the - speculum where the eye-piece is fitted. - -These absorbing occupations were interrupted by the unwelcome news -that Dietrich, the youngest of the Herschel family, had decamped from -Hanover “with a young idler” like himself. William instantly started -for Holland, where the fugitive was supposed to be about to take -ship for India, but missed his track; and, after having extended his -journey to Hanover to comfort his anxious mother--his father had died -in 1767--returned sadly to Bath. There, to his immense surprise, he -found the scapegrace in strict charge of his sister, “who kept him to -a diet of roasted apples and barley-water.” His ineffectual escapade -had terminated with an attack of illness at Wapping, whither Alexander -Herschel, on learning how matters stood, had posted off to take him in -charge and watch his recovery. Musical occupation was easily procured -for him at Bath, since he was an accomplished violinist--had, indeed, -started on his unprosperous career in the guise of an infant prodigy; -but he threw it up in 1779 and drifted back to Hanover, married a Miss -Reif, and settled down to live out a fairly long term of shiftless, -albeit harmless, existence. - -In 1776 William Herschel succeeded Thomas Linley, Sheridan’s -father-in-law, as Director of the Public Concerts at Bath. His duties -in this capacity, while the season lasted, were most onerous. He had to -engage performers, to appease discontents, to supply casual failures, -to write glees and catches expressly adapted to the voices of his -executants, frequently to come forward himself as a soloist on the -hautboy or the harpsichord. The services of his brother Alexander, a -renowned violoncellist, and of his sister, by this time an excellent -singer, were now invaluable to him. Nor for musical purposes solely. -The vision of the skies was never lost sight of, and the struggle -to realise it in conjunction with his sympathetic helpers absorbed -every remnant of time. At meals the only topics of conversation were -mechanical devices for improving success and averting failure. William -ate with a pencil in his hand, and a project in his head. Between the -acts at the theatre, he might be seen running from the harpsichord to -his telescope. After a rehearsal or a morning performance, he would -dash off to the workshop in periwig and lace ruffles, and leave it -but too often with those delicate adjuncts to his attire torn and -pitch-bespattered. Accidents, too, menacing life and limb, were a -consequence of that “uncommon precipitancy which accompanied all his -actions;” but he escaped intact, save for the loss of a finger-nail. - -His introduction to the learned world of Bath was thus described by -himself:-- - - “About the latter end of December, 1779, I happened to be - engaged in a series of observations on the lunar mountains; - and the moon being in front of my house, late in the evening I - brought my seven-feet reflector into the street, and directed - it to the object of my observations. Whilst I was looking into - the telescope, a gentleman, coming by the place where I was - stationed, stopped to look at the instrument. When I took my - eye off the telescope, he very politely asked if he might be - permitted to look in, and this being immediately conceded, he - expressed great satisfaction at the view.” - -The inquisitive stranger called next morning, and proved to be Dr. -(later Sir William) Watson. He formed on the spot an unalterable -friendship for the moon-struck musician, and introduced him to a -Philosophical Society which held its meetings at his father’s house. -Herschel’s earliest essays were read before it, but they remained -unpublished. His first printed composition appeared in the “Ladies’ -Diary” for 1780. It was an answer to a prize question on the vibration -of strings. - -The long series of his communications to the Royal Society of London -opened May 11th, 1780, with a discussion of his observations, begun in -October, 1777, of Mira, the variable star in the neck of the Whale. As -to the theory of its changes, he agreed with Keill that they could best -be explained by supposing rotation on an axis to bring a lucid side and -a side obscured by spots alternately into view. A second paper by him -on the Mountains of the Moon was read on the same day. He measured, in -all, about one hundred of these peaks and craters. - -In January, 1781, there came an essay stamped with the peculiar impress -of his genius, entitled “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.” It embodied an attempt to -apply a definite criterion to the time-keeping of our planet. But the -prospect is exceedingly remote of rating one planet-clock by the other. -Herschel’s methods of inquiry are, however, aptly illustrated in this -curiously original paper. His speculations always invited the control -of facts. If facts were not at hand, he tried somehow to collect them. -The untrammelled play of fancy was no more to his mind than it was to -Newton’s. His ardent scientific imagination was thus, by the sobriety -of his reason, effectively enlisted in the cause of progress. - -Herschel began in 1780 his second review of the heavens, using a -seven-foot Newtonian, of 6¼ inches aperture, with a magnifying power -of 227. “For distinctness of vision,” he said, “this instrument is, -perhaps, equal to any that was ever made.” His praise was amply -justified. As he worked his way with it through the constellation -Gemini, on the night of March 13th, 1781, an unprecedented event -occurred. “A new planet swam into his ken.” He did not recognise it as -such. He could only be certain that it was not a fixed star. His keen -eye, armed with a perfect telescope, discerned at once that the object -had a disc; and the application of higher powers showed the disc to be -a substantial reality. The stellar “patines of bright gold” will not -stand this test. Being of purely optical production, they gain nothing -by magnification. - -At that epoch new planets had not yet begun to be found by the dozen. -Five, besides the earth, had been known from the remotest antiquity. -Five, and no more, seemed to have a prescriptive right to exist. The -boundaries of the solar system were of immemorial establishment. It was -scarcely conceivable that they should need to be enlarged. The notion -did not occur to Herschel. His discovery was modestly imparted to the -Royal Society as “An Account of a Comet.” He had, indeed, noticed -that the supposed comet moved in planetary fashion from west to east, -and very near the ecliptic; and, after a few months, its true nature -was virtually proved by Lexell of St. Petersburg. On November 28th, -Herschel measured, with his freshly-invented “lamp-micrometer,” the -diameter of this “singular star;” and it was not until a year later, -November 7th, 1782, that he felt sufficiently sure of its planetary -status to exercise his right of giving it a name. Yet this, in the -long run, he failed to accomplish. The appellation “Georgium Sidus,” -bestowed in honour of his patron, George III., never crossed the -Channel, and has long since gone out of fashion amongst ourselves. -Lalande tried to get the new planet called “Herschel;” but the title -“Uranus,” proposed by Bode, of Berlin, was the “fittest,” and survived. - -This discovery made the turning-point of Herschel’s career. It -transformed him from a music-master into an astronomer. Without it -his vast abilities would probably have been in great measure wasted. -No man could long have borne the strain of so arduous a double life -as he was then leading. Relief from it came just in time. It is true -that fame, being often more of a hindrance than a help, brought -embarrassments in its train. In November, 1781, Herschel was compelled -to break the complex web of his engagements at Bath by a journey to -London for the purpose of receiving in person the Copley Medal awarded -to him by the Royal Society, of which body he was, some days later, -elected a Fellow. At home, he was persecuted by admirers; and they -were invariably received with an easy suavity of manner that gave no -hint of preoccupation. Everyone of scientific pretension who visited -Bath sought an interview with the extraordinary man who, by way of -interlude to pressing duties, had built telescopes of unheard-of -power, and performed the startling feat of adding a primary member -to the solar system. Among the few of these callers whose names have -been preserved were Sir Harry Englefield, Sir Charles Blagden, and Dr. -Maskelyne, then, and for thirty years afterwards, Astronomer-Royal. -“With the latter,” Miss Herschel relates, “he (William) 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!’” The phrase was doubtless meant as a sign of regard, for -the acquaintance thus begun ripened into cordial intimacy. And William -Herschel never lost or forgot a friend. - -As regards music alone, the winter of 1781–82 was an exceptionally busy -one. He had arranged to conduct, jointly with Rauzzini, a Roman singer -and composer, a series of oratorios; undertaking, besides, pecuniary -responsibilities which turned out little to his advantage. The labour, -vexation, and disappointment involved in carrying out this unlucky plan -can readily be imagined. But neither the pressure of business, nor -the distractions of celebrity, checked the ardour of his scientific -advance. The review which afforded him the discovery of Uranus, and the -materials for his first catalogue of 269 double stars, was completed -in 1781; and a third, made with the same beautiful instrument, bearing -the high magnifying power of 460, was promptly begun. This had for one -of its special objects the ascertainment of possible changes in the -heavens since Flamsteed’s time; and in the course of it many thousands -of stars came under scrutiny, directed to ascertain their magnitude and -colour, singleness or duplicity, hazy or defined aspect. - -The first of Herschel’s _effective_ twenty-foot telescopes was erected -at 19, New King Street, in the summer of 1781. Enclosing a mirror -twelve inches in diameter, it far surpassed any seeing-machine that had -ever existed in the world. Yet its maker regarded it as only marking -a step in his upward progress. A speculum of thirty-feet focus was -the next object of his ambition. For its achievement no amount of -exertion was counted too great. Its composition was regulated by fresh -experiments on various alloys of copper and tin. Its weight and shape -were again and again calculated, and the methods appropriate to its -production earnestly discussed. “I saw nothing else,” Caroline Herschel -tells us, “and heard nothing else talked of but these things when my -brothers were together.”[B] - - [B] In borrowing Miss Herschel’s lively narratives and - comments, some obvious slips in grammar and construction - have been corrected. Quotations, too, from the writings - of Sir William and Sir John Herschel are often slightly - abridged. - -“The mirror,” she continues, “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. 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.” - -The matter was never out of the master’s thoughts. “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.” - -At last, the concert season being over, and everything in readiness -for the operation of casting, “the metal,” we hear from the same -deeply-interested eyewitness, “was in the furnace; but, 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. My poor -brother William fell, exhausted with heat and exertion, on a heap of -brickbats. Before the second casting was attempted, everything which -could ensure success had been attended to, and a very perfect metal was -found in the mould, which had cracked in the cooling.” - -This second failure terminated the enterprise. Not that it was -abandoned as hopeless, but because of a total change in the current of -affairs. Herschel’s fame had stirred the royal curiosity, and rumours -had now and again reached Bath that he was to be sent for to court. In -the spring of 1782 the actual mandate arrived; and on May 8th, leaving -his pupils and his projects to shift for themselves, he set out for -London. He carried with him his favourite seven-foot reflector, and all -the apparatus necessary for viewing double stars and other objects of -interest. On May 25th he wrote to his sister:-- - -“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 honour 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.... Tell Alexander that everything looks -very like as if I were to stay here. The King enquired after him, and -after my great speculum. He also gave me leave to come and hear the -Griesbachs (Herschel’s nephews) play at the private concert which he -has every evening.... All my papers are printing, 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.” - -His next letter is dated June 3rd, 1782. “I pass my time,” he informed -“Lina,” “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.... I am -introduced to the best company. To-morrow I dine at Lord Palmerston’s, -next day with Sir Joseph Banks, 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 endeavour to -do so.” - -A comparison of his telescope with those at the Royal Observatory -showed its striking superiority, although among them was one of Short’s -famous Gregorians, of 9½ inches aperture. It had thus a reflecting -surface above twice that of Herschel’s seven-foot, the competition -with which was nevertheless so disastrous to its reputation that Dr. -Maskelyne fell quite out of conceit with it, and doubted whether it -_deserved_ the new stand constructed for it on the model of Herschel’s. - -In the midst of these scientific particulars, we hear incidentally that -influenza was then so rife in London that “hardly one single person” -escaped an attack. - -On July 2nd he made his first appearance as showman of the heavens to -royalty. The scene of the display was Buckingham House (now Buckingham -Palace). “It was a very fine evening,” he wrote to his sister. “My -instrument gave general satisfaction. The King has very good eyes, and -enjoys observations with telescopes exceedingly.” - -Next night, the King and Queen being absent at Kew, the Princesses -desired an exhibition. But, since they objected to damp grass, the -telescope, Herschel says, “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 the speculum, the -micrometers, the movements of the telescope, 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 seemed to be much -pleased with the artifice.” From a somewhat prolonged conversation, -he judged them to be “extremely well instructed,” and “most amiable -characters.” - -Shortly afterwards Herschel received the appointment of royal -astronomer, with the modest salary of £200 a year. “Never,” exclaimed -Sir William Watson on being made acquainted with its amount, “bought -monarch honour so cheap!” The provision was assuredly not munificent; -yet it sufficed to rescue a great man from submergence under the hard -necessities of existence. The offer was critically timed. It was made -precisely when teaching and concert-giving had come to appear an -“intolerable waste of time” to one fired with a visionary passion. -“Stout Cortes” staring at the Pacific, Ulysses starting from Ithaca to -“sail beyond the sunset,” were not more eager for experience of the -Unknown. - - - - -CHAPTER II. - -THE KING’S ASTRONOMER. - - -William Herschel was now an appendage to the court of George III. He -had to live near Windsor, and a large dilapidated house on Datchet -Common was secured as likely to meet his unusual requirements. The -“flitting” took place August 1, 1782. William was in the highest -spirits. There were stables available for workrooms and furnaces; a -spacious laundry that could be turned into a library; a fine lawn for -the accommodation of the great reflector. Crumbling walls and holes -in the roof gave him little or no concern; and if butcher’s meat was -appallingly dear (as his sister lamented) the family could live on -bacon and eggs! In this sunny spirit he entered upon the career of -untold possibilities that lay before him. - -Nevertheless the King’s astronomer did not find it all plain sailing. -His primary duty was to gratify the royal taste for astronomy, and this -involved no trifling expenditure of time and toil. The transport of the -seven-foot to the Queen’s lodge could be managed in the daylight, but -its return-journey in the dark, after the conclusion of the celestial -raree-show, was an expensive and a risky business; yet fetched back it -should be unless a clear night were to be wasted--a thing not possible -to contemplate. This kind of attendance was, however, considerately -dispensed with when its troublesome nature came to be fully understood. -Herschel’s treatment by George III. has often been condemned as -selfish and niggardly; but with scant justice. In some respects, no -doubt, it might advantageously have been modified. Still, the fact -remains that the astronomer of Slough was the gift to science of the -poor mad King. From no other crowned head has it ever received so -incomparable an endowment. - -Herschel’s salary was undeniably small. It gave him the means of -living, but not of observing, as he proposed to observe. If the -improvement of telescopes were to be “carried to its utmost limit,” -additional funds must be raised. Without an ample supply of the “sinews -of war,” fresh campaigns of exploration were out of the question. There -was one obvious way in which they could be provided. Herschel’s fame as -an optician was spread throughout Europe. His telescopes were wanted -everywhere, but could be had from himself alone; for the methods by -which he wrought specula to a perfect figure are even now undivulged. -They constituted, therefore, a source of profit upon which he could -draw to almost any extent. He applied himself, accordingly, to make -telescopes for sale. They brought in large sums. Six hundred guineas -a-piece were paid to him by the King for four ten-foot reflectors; he -received at a later date £3,150 for a twenty-five foot, sent to Spain; -and in 1814 £2,310 from Lucien Bonaparte for two smaller instruments. -The regular scale of prices (later considerably reduced) began with 200 -guineas for a seven-foot, and mounted to 2,500 for a twenty-foot; and -the commissions executed were innumerable. - -But Herschel did not come into the world to drive a lucrative trade. -It was undertaken, not for itself, but for what was to come of it; yet -there was danger lest the end should be indefinitely postponed in the -endeavour to secure the means. - -“It seemed to be supposed,” Miss Herschel remarked, “that enough had -been done when my brother was enabled to leave his profession that he -might have time to make and sell telescopes. But all this was only -retarding the work of a thirty or forty-foot instrument, which it was -his 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 the cause of astronomy by giving up his time to -making telescopes for other observers.” - -This he was, fortunately, not long obliged to do. A royal grant of -£2,000 for the construction of the designed giant telescope, followed -by another of equal amount, together with an annual allowance of -£200 for its repairs, removed the last obstacle to his success. The -wide distribution of first-class instruments might, indeed, have -been thought to promise more for the advancement of astronomy than -the labours of a single individual. No mistake could be greater. Not -an observation worth mentioning was made with any of the numerous -instruments sent out from Datchet or Slough, save only those acquired -by Schröter and Pond. The rest either rusted idly, or were employed -ineffectually, aptly illustrating the saying that “the man at the -eye-end” is the truly essential part of a telescope. - -No one knew this better than Herschel. Every serene dark night was -to him a precious opportunity availed of to the last minute. The -thermometer might descend below zero, ink might freeze, mirrors might -crack; but, provided the stars shone, he and his sister worked on -from dusk to dawn. In this way, his “third review,” begun at Bath, -was finished in the spring of 1783. The swiftness with which it was -conducted implied no want of thoroughness. “Many a night,” he states, -“in the course of eleven or twelve hours of observation, I have -carefully and singly examined not less than 400 celestial objects, -besides taking measures, and sometimes viewing a particular star for -half an hour together, with all the various powers.” - -The assiduity appears well-nigh incredible with which he gathered in -an abundant harvest of nebulæ and double stars; his elaborate papers, -brimful of invention and experience, being written by day, or during -nights unpropitious for star-gazing. On one occasion he is said to -have worked without intermission at the telescope and the desk for -seventy-two hours, and then slept unbrokenly for twenty-six hours. His -instruments were never allowed to remain disabled. They were kept, -like himself, on the alert. Relays of specula were provided, and one -was in no case removed from the tube for re-polishing, unless another -was ready to take its place. Even the meetings of the Royal Society -were attended only when moonlight effaced the delicate objects of his -particular search. - -The summer of 1788 was spent in getting ready the finest telescope -Herschel had yet employed. It was called the “large twenty-foot” -because of the size of its speculum, which was nearly nineteen inches -in diameter; and with its potent help he executed his fourth and -last celestial survey. His impatience to begin led him into perilous -situations. - -“My brother,” says Miss Herschel, “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 labouring -men were called up to help in extricating the mirror, which was -fortunately uninjured, but much work was cut out for carpenters next -day.” - -In the following March, he himself wrote to Patrick Wilson, of Glasgow, -son of Dr. Alexander Wilson, the well-known professor of astronomy:--“I -have finished a second speculum to my new twenty-foot, very much -superior to the first, and am now reviewing the heavens with it. This -will be a work of some years; but it is to me so far from laborious -that it is attended with the utmost delight.” He, nevertheless, looked -upon telescopes as “yet in their infant state.” - -The ruinous mansion at Datchet having become uninhabitable, even -by astronomers, their establishment was shifted, in June, 1785, to -Clay Hall, near Old Windsor. Here the long-thought-of forty-foot was -begun, but was not destined to be finished. A litigious landlady -intervened. The next move, however, proved to be the last. It was to -a commodious residence at Slough, now called “Observatory House”--“le -lieu du monde,” wrote Arago, “où il a été fait le plus de découvertes.” -Thither, without the loss of an hour, in April, 1786, the machinery and -apparatus collected at Clay Hall were transported. Yet, “amidst all -this hurrying business,” Caroline remembered “that every moment after -daylight was allotted to observing. 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.” - -During the ensuing three months, thirty to forty workmen were -constantly employed, “some in felling and rooting out trees, some in -digging and preparing the ground for the bricklayers who were laying -the foundation for the telescope.” “A whole troop of labourers” were, -besides, engaged in reducing “the iron tools to a proper shape for the -mirror to be ground upon.” Thus, each morning, when dawn compelled -Herschel to desist from observation, he found a bevy of people awaiting -instructions of all sorts from him. “If it had not been,” his sister -says, “for the intervention of a cloudy or moonlit night, I know not -when he, or I either, should have got any sleep.” The wash-house was -turned into a forge for the manufacture of specially designed tools; -heavy articles cast in London were brought by water to Windsor; the -library was so encumbered with stores, models, and implements, that “no -room for a desk or an atlas remained.” - -On July 3rd, 1786, Herschel, accompanied by his brother Alexander, -started for Göttingen, commissioned by the King to present to the -University one of the ten-foot reflectors purchased from him. He was -elected a Member of the Royal Society of Göttingen, and spent three -weeks at Hanover with his aged mother, whom he never saw again. During -his absence, however, the forty-foot progressed in accordance with -the directions he had taken care to leave behind. He trusted nothing -to chance. “There is not one screwbolt,” his sister asserted, “about -the whole apparatus but what was fixed under the immediate eye of -my brother. I have seen him lie stretched many an hour in a burning -sun, across the top beam, whilst the iron-work for the various motions -was being fixed. At one time no less than twenty-four men (twelve and -twelve relieving each other) kept polishing day and night; my brother, -of course, never leaving them all the while, taking his food without -allowing himself time to sit down to table.” - -At this stage of the undertaking it became the fashion with visitors to -use the empty tube as a promenade. Dr. and Miss Burney called, in July, -1786, “to see, and _take a walk_ through the immense new telescope.” -“It held me quite upright,” the authoress of “Evelina” related, “and -without the least inconvenience; so would it have done had I been -dressed in feathers and a bell-hoop.” - -George III. and the Archbishop of Canterbury followed the general -example; and the prelate being incommoded by the darkness and the -uncertain footing, the King, who was in front, turned back to help him, -saying: “Come, my lord bishop, I will show you the way to heaven.” On -another occasion “God save the King” was sung and played within the -tube by a large body of musicians; and the rumour went abroad that it -had been turned into a ball-room! - -The University of Oxford conferred upon Herschel, in 1786, an honorary -degree of LL.D.; but he cared little for such distinctions. Miss -Burney characterised him as a “man without a wish that has its object -in the terrestrial globe;” the King had “not a happier subject.” The -royal bounty, she went on “enables him to put into 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.” Nor was it possible to “admire his genius more -than his gentleness.” Again, after taking tea in his company in the -Queen’s lodge: “this very extraordinary man 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.” Mrs. Papendick, another court chronicler, says that “he was -fascinating in his manner, and possessed a natural politeness, and the -abilities of a superior nature.” - -His great telescope took rank, before and after its completion, as the -chief scientific wonder of the age. Slough was crowded with sightseers. -All the ruck of Grand Dukes and Serene Highnesses from abroad, besides -royal, noble, and gentle folk at home, flocked to gaze at it and -interrogate its maker with ignorant or intelligent wonder. The Prince -of Orange was a particularly lively inquirer. On one of his calls at -Slough, about ten years after the erection of the forty-foot, finding -the house vacant, he left a memorandum asking if it were true, as the -newspapers reported, that “Mr. Herschel had discovered a new star whose -light was not as that of the common stars, but with swallow-tails, as -stars in embroidery?”! - -Pilgrim-astronomers came, too--Cassini, Lalande, Méchain and Legendre -from Paris, Oriani from Milan, Piazzi from Palermo. Sniadecki, director -of the observatory of Cracow, “took lodgings,” Miss Herschel relates, -“in Slough, for the purpose of seeing and hearing my brother whenever -he could find him at leisure. He was a very silent man.” One cannot -help fearing that he was also a very great bore. Von Magellan, another -eminent foreign astronomer, communicated to Bode an interesting account -of Herschel’s methods of observation. The multitude of entries in his -books astonished him. In sweeping, he reported, “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.” The thermometer in the garden -stood that night, January 6th, 1785, at 13 deg. Fahrenheit; but the -royal astronomer, his visitor remarked, “has an excellent constitution, -and thinks about nothing else in the world but the celestial bodies.” - -In January, 1787, Herschel made trial with his twenty-foot reflector -of the “front-view” plan of construction, suggested by Lemaire in -1732, but never before practically tested. All that had to be done -was to remove the small mirror, and slightly _tilt_ the large one. -The image was then formed close to the upper margin of the tube, into -which the observer, turning his back to the heavens, looked down. The -purpose of the arrangement was to save the light lost in the second -reflection; and its advantage was at once illustrated by the discovery -of two Uranian moons--one (Titania) circling round its primary in about -8¾ hours, the other (Oberon) in 13½ hours. In order to assure these -conclusions, he made a sketch beforehand of what _ought_ to be seen on -February 10th; and on that night, to his intense satisfaction, “the -heavens,” as he informed the Royal Society, “displayed the original of -my drawing 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, the little secondary planets -seeming to give a dignity to the primary one which raises it into a -more conspicuous situation among the great bodies of our solar system.” - -This brilliant result determined him to make a “front-view” of -the forty-foot. Its advance towards completion was not without -vicissitudes. The first speculum, when put into the tube, February -19th 1787, was found too thin to maintain its shape. A second, cast -early in 1788, cracked in cooling. The same metal having been recast -February 16th, the artist tried it upon Saturn in October; but the -effect disappointing his expectation, he wrought at it for ten months -longer. At last, after a few days’ polishing with his new machine, he -turned the great speculum towards Windsor Castle; when its high quality -became at once manifest. And such was his impatience to make with it -a crucial experiment, that--as he told Sir Joseph Banks--he directed -it to the heavens (August 28th, 1789) before it had half come to its -proper lustre. The stars came out well, and no sooner had he got hold -of Saturn than a sixth satellite stood revealed to view! Its “younger -brother” was detected September 17th; and the two could be seen, on -favourable opportunities, threading their way, like beads of light, -along the lucid line of the almost vanished ring. Herschel named them -Enceladus and Mimas, and found, on looking up his former observations -of Saturn, that Enceladus, the exterior and brighter object, had been -unmistakably seen with the twenty-foot, August 19th, 1787. Mimas is a -very delicate test of instrumental perfection. - -The mirror by which it was first shown measured nearly fifty inches -across, and weighed 2,118 pounds. It was slung in a ring, and the -sheet-iron tube in which it rested was thirty-nine and a-half feet -long and four feet ten inches wide. Ladders fifty feet in length -gave access to a movable stage, from which the observer communicated -through speaking tubes with his assistants. The whole erection stood -on a revolving platform; for the modern equatorial form of mount, by -which the diurnal course of the heavens is automatically followed, was -not then practically available, and the necessary movements had to be -imparted by hand. This involved the attendance of two workmen, but was -otherwise less inconvenient than might be supposed, owing to the skill -with which the required mechanism was contrived. - -Herschel estimated that, with a magnifying-power of 1,000, this grand -instrument could, in the climate of England, be effectively used during -no more than one hundred hours of every year. A review with it of the -whole heavens would hence have occupied eight centuries. In point of -fact, he found the opportunities for its employment scarce. The machine -took some time to get started, while the twenty-foot was ready in ten -minutes. The speculum, moreover, proved unpleasantly liable to become -dewed in moist weather, or frozen up in cold; and, in spite of all -imaginable care, it preserved the delicacy of its polish no more than -two years. An economist of minutes, such as its maker, could, then, -do no otherwise than let the giant telescope lie by unless its powers -were expressly needed. They were surprisingly effective. “With the -forty-foot instrument,” he reported to the Royal Society in 1800, “the -appearance of Sirius announced itself at a great distance like the dawn -of the morning, till this brilliant star at last entered the field, -with all the splendour of the rising sun, and forced me to take my eye -from that beautiful sight.” Which, however, left the vision impaired -in delicacy for nigh upon half-an-hour. - -Thus the results gathered from the realisation of Herschel’s crowning -optical achievement fell vastly short of what his imagination had -pictured. The promise of the telescope’s initial disclosures was not -realised in its subsequent career. Yet it was a superb instrument. -The discovery with it of Mimas gave certain proof that the figure of -the speculum was as perfect as its dimensions were unusual. But its -then inimitable definition probably fell off later. Its “broad bright -eye” was, for the last time, turned towards the heavens January 19th, -1811, when the Orion nebula showed its silvery wings to considerable -advantage. But incurable dimness had already set in--incurable, because -the artist’s hand had no longer the strength needed to cure the growing -malady. The big machine was, however, left standing, framework and all. -It figured as a landmark on the Ordnance Survey Map of England; and, -stamped in miniature on the seal of the Royal Astronomical Society, -aptly serves to illustrate its motto, “_Quicquid nitet notandum_.” -At last, on New Years Eve, 1839, the timbers of the scaffolding -being dangerously decayed, it was, with due ceremony, dismounted. A -“Requiem,” composed by Sir John Herschel, was sung by his family, -fourteen in number, assembled within the tube, which was then riveted -up and laid horizontally on three stone piers in the garden at Slough. -“It looks very well in its new position,” Sir John thought. Yet it has -something of a _memento mori_ aspect. It seems to remind one that the -loftiest human aspirations are sprinkled “with the dust of death.” The -speculum adorns the hall of Observatory House. - -Herschel married, May 8th, 1788, Mary, the only child of Mr. James -Baldwin, a merchant in the City of London, and widow of Mr. John Pitt. -She was thirty-eight and he fifty. Her jointure relieved him from -pecuniary care, and her sweetness of disposition secured his domestic -happiness. They set up a curious double establishment, taking a house -at Upton, while retaining that at Slough. Two maidservants were kept -in each, and a footman maintained the communications. So at least runs -Mrs. Papendick’s gossip. Miss Burney records in her Diary a tea at Mr. -De Luc’s, where Dr. Herschel accompanied a pair of vocalists “very -sweetly on the violin. His newly-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.” - -He was now at the height of prosperity and renown. Diplomas innumerable -were showered upon him by Academies and learned societies. In a letter -to Benjamin Franklin, he returned thanks for his election as a member -of the American Philosophical Society, and acquainted him with his -recent detection of a pair of attendants on the “Georgian planet.” -A similar acknowledgment was addressed to the Princess Daschkoff, -Directress of the Petersburg Academy of Sciences. The King of Poland -sent him his portrait; the Empress Catherine II. opened negotiations -for the purchase of some of his specula, Lucien Bonaparte repaired -to Slough incognito; Joseph Haydn snatched a day from the turmoil -of his London engagements to visit the musician-astronomer, and -gaze at his monster telescopes. By universal agreement, Dr. Burney -declared, Herschel was “one of the most pleasing and well-bred natural -characters of the day, as well as the greatest astronomer.” They had -much in common, according to Dr. Burney’s daughter. Both possessed an -uncommon “suavity of disposition”; both loved music; and Dr. Burney had -a “passionate inclination for astronomy.” They became friends through -the medium of Dr. Burney’s versified history of that science. In -September, 1797, he called at Slough with the manuscript in his valise. -“The good soul was at dinner,” he relates; and, to his surprise, since -he was ignorant of Herschel’s marriage, the company included several -ladies, besides “a little boy.” He was, nothing loth, compelled to stay -over-night; discussed with his host the plan of his work, and read to -him its eighth chapter. Herschel listened with interest, and modestly -owned to having learnt much from what he had heard; but presently -dismayed the author by confessing his “aversion to poetry,” which -he had generally regarded as “an arrangement of fine words without -any adherence to the truth.” He added, however, that “when truth and -science were united to those fine words,” they no longer displeased -him. The readings continued at intervals, alternately at Slough and -Chelsea, to the immense gratification of the copious versifier, who -occasionally allowed his pleasure to overflow in his correspondence. - -“Well, but Herschel has been in town,” he wrote from Chelsea College, -December 10th, 1798, “for short spurts and back again, two or three -times, and I have had him here two whole days. I read to him the first -five books without any one objection.” And again; “He came, and his -good wife accompanied him, and I read four and a-half books; and on -parting, still more humble than before, or still more amiable, he -thanked me for the instruction and entertainment I had given him. What -say you to that? Can anything be grander?” - -In spite of his “aversion,” Herschel had once, and once only, wooed the -coy muse himself. The first evening paper that appeared in England, May -3rd, 1788, contained some introductory quatrains by him. An excuse for -this unwonted outburst may be found in the circumstance that the sheet -in which they were printed bore the name of _The Star_. They began with -the interrogation: - - “What Star art thou, about to gleam - In Novelty’s bright hemisphere?” - -and continued: - - “A Planet wilt thou roll sublime, - Spreading like Mercury thy rays? - Or chronicle the lapse of Time, - Wrapped in a Comet’s threatening blaze?” - -That they are of the schoolboy order need surprise no one. Such a mere -sip at the “Pierian spring” could scarcely bring inspiration. - -Herschel’s grand survey of the heavens closed with his fourth review. -His telescopic studies thereupon became specialised. The sun, the -planets and their satellites, the lately discovered asteroids, certain -double stars, and an occasional comet, in turn received attention. -Laboratory experiments were also carried on, and discussions of -profound importance were laid before the Royal Society. All this -cost him but little effort. The high tension of his earlier life was -somewhat relaxed; he allowed himself intervals of rest, and indulged -in social and musical recreations. Concerts were now frequently given -at his house; and the face of beaming delight with which he presided -over them is still traditionally remembered. Visits to Sir William -Watson at Dawlish gave him opportunities, otherwise rare, for talks on -metaphysical subjects; and he stayed with James Watt at Heathfield in -1810. He had been a witness on his side in an action for infringement -of patent in 1793. - -Herschel rented a house on Sion Hill, Bath, for some months of the year -1799; and from time to time stayed with friends in London, or sought -change of air at Tunbridge Wells, Brighton, or Ramsgate. In July, -1801, he went to Paris with his wife and son, made acquaintance with -Laplace, and had an interview with the First Consul. It was currently -reported that Bonaparte had astonished him by the extent of his -astronomical learning; but the contrary was the truth. He had tried to -be impressive, but failed. Herschel gave an account of what passed to -the poet Campbell, whom he met at Brighton in 1813. - -“The First Consul,” he said, “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 was something like -affecting to know more than he did know.” Herschel’s election in 1802 -as one of the eight foreign Associates of the French Institute was -probably connected with his Parisian experiences. - -He inspired Campbell with the most lively enthusiasm. “His simplicity,” -he wrote, “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 labours with a sort of boyish -earnestness to explain. 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 the 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.” - -The appearance of a bright comet, in October, 1806, drew much company -to Slough. On the 4th, Miss Herschel narrates, “Two parties from the -Castle came to see it, 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 from which he never -got the better afterwards; for on that day 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 to put on -proper clothing, or for the least nourishment to pass his lips. Among -the company I remember were the Duke of Sussex, Prince Galitzin, Lord -Darnley, a number of officers, Admiral Boston, and some ladies.” - -A dangerous attack of illness in the spring of 1807 left Herschel’s -strength permanently impaired. But he travelled to Scotland in the -summer of 1810, and received the freedom of the City of Glasgow. -Then, in 1814, he made a final, but fruitless attempt, to renovate -the four-foot speculum. In the midst of the confusion attending upon -the process, word was given to prepare for the reception of the Czar -Alexander, the Duchess of Oldenburg, and sundry other grandees just -then collected at Windsor for the Ascot races. The setting to rights -was no small job; “but we might have saved ourselves the trouble,” his -sister remarks drily, “for they were sufficiently harassed with public -sights and festivities.” - -On April 5th, 1816, Herschel was created a Knight of the Royal -Hanoverian Guelphic Order, and duly attended one of the Prince Regent’s -levées in May. He went to town in 1819 to have his portrait painted -by Artaud. The resulting fine likeness is in the possession of his -grandson, Sir William James Herschel. The Astronomical Society chose -him as its first President in 1821; and he contributed to the first -volume of its memoirs a supplementary list of 145 double stars. The -wonderful series of his communications to the Royal Society closed -when he was in his eightieth year, with the presentation, June 11th, -1818, of a paper on the Relative Distances of Star-clusters. On June -1st, 1821, he inserted into the tube with thin and trembling hands -the mirror of the twenty-foot telescope, and took his final look at -the heavens. All his old instincts were still alive, only the bodily -power to carry out their behests was gone. An unparalleled career of -achievement left him unsatisfied with what he had done. Old age brought -him no Sabbath rest, but only an enforced and wearisome cessation from -activity. His inability to re-polish the four-foot speculum was the -doom of his _chef d’œuvre_. He could not reconcile himself to it. His -sunny spirits gave way. The old happy and buoyant temperament became -overcast with despondency. His strong nerves were at last shattered. - -On August 15th, 1822, Miss Herschel relates:--“I hastened to the spot -where I was wont to find him with the newspaper I was to read to him. -But I was informed my brother had been obliged to return to his room, -whither I flew immediately. Lady Herschel 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[C] 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 whispered inquiries if they -were locked, and the key safe.” - - [C] The grandson of one of Herschel’s earliest English friends. - -He died ten days later, August 25th, 1822. Above his grave, in the -church of Saint Laurence at Upton, the words are graven:--“Coelorum -perrupit claustra”--He broke through the barriers of the skies. - -William Herschel was endowed by nature with an almost faultless -character. He had the fervour, without the irritability of genius; he -was generous, genial, sincere; tolerant of ignorance; patient under the -acute distress, to which his situation rendered him peculiarly liable, -of unseasonable interruptions at critical moments: he was warm-hearted -and open-handed. His change of country and condition, his absorption -in science, the homage paid to him, never led him to forget the claims -of kindred. Time and money were alike lavished in the relief of family -necessities. He supported his brother Alexander after his retirement -from the concert-stage in 1816, until his death at Hanover, March 15th, -1821. Dietrich’s recurring misfortunes met his unfailing pity and -help. He bequeathed to him a sum of £2,000, and to his devoted sister, -Caroline, an annuity of £100. - -His correspondents, abroad and at home, were numerous; nor did he -disdain to remove the perplexities of amateurs. In a letter, dated -January 6th, 1794, we find him explaining to Mr. J. Miller of Lincoln’s -Inn, “the circumstances which attend the motion of a race-horse upon -a circle of longitude.” And he wrote shortly afterwards to Mr. Smith -of Tewkesbury:--“You find fault with the principles of gravitation -and projection because they will not account for the rotation of the -planets upon their axes. You might certainly with as much reason find -fault with your shoes because they will not likewise serve your hands -as gloves. But, in my opinion, the projectile motion once admitted, -sufficiently explains the rotatory motion; for it is hardly possible -mechanically to impress the one without giving the other at the same -time.” - -On religious topics he was usually reticent; but a hint of the reverent -spirit in which his researches were conducted may be gathered from -a sentence in the same letter. “It is certainly,” he said, “a very -laudable thing to receive instruction from the great workmaster of -nature, and for that reason all experimental philosophy is instituted.” - -To investigate was then, in his view, to “receive instruction”; and one -of the secrets of his wonderful success lay in the docility with which -he came to be taught. - - - - -CHAPTER III. - -THE EXPLORER OF THE HEAVENS. - - -“A knowledge of the construction of the heavens,” Herschel wrote -in 1811, “has always been the ultimate object of my observations.” -The “Construction of the Heavens”! A phrase of profound and novel -import, for the invention of which he was ridiculed by Brougham in the -_Edinburgh Review_; yet expressing, as it had never been expressed -before, the essential idea of sidereal astronomy. Speculation there had -been as to the manner in which the stars were grouped together; but the -touchstone of reality had yet to be applied to them. This unattempted, -and all but impossible enterprise Herschel deliberately undertook. It -presented itself spontaneously to his mind as worth the expenditure -of a life’s labour; and he spared nothing in the disbursement. The -hope of its accomplishment inspired his early exertions, carried him -through innumerable difficulties, lent him audacity, fortified him in -perseverance. For this, - - “He left behind the painted buoy - That tosses at the harbour’s mouth,” - -and burst his way into an unnavigated ocean. - -Herschel has had very few equals in his strength of controlled -imagination. He held the balance, even to a nicety, between the -real and the ideal. Meditation served in him to prescribe and guide -experience; experience to ripen the fruit of meditation. - -“We ought,” he wrote in 1785, “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.” - -This was consistently his method. If thought outran sight, he laboured -earnestly that it should be overtaken by it: while sight, in turn, -often took the initiative, and suggested thought. He was much more than -a simple explorer. “Even at the telescope,” Professor Holden says, “his -object was not discovery merely, but to know the inner constitution of -the heavens.” He divined, at the same time that he observed. - -The antique conception of the heavens as a hollow sphere upon which -the celestial bodies are seen projected, survived then, and survives -now, as a convenient fiction for practical purposes. But in the -eighteenth century the fiction assumed to the great majority a sort of -quasi-reality. Herschel made an exception in being vividly impressed -with the _depth_ of space. How to sound that depth was the first -problem that he attacked. As a preliminary to further operations, he -sought to fix a unit of sidereal measurement. The distances from the -earth to the stars were then altogether unknown. All that had been -ascertained was that they must be very great. Instrumental refinements -had not, in fact, been carried far enough to make the inquiry -profitable. Herschel did not underrate its difficulty. He recognised -that, in pursuing it, _one hundredth of a second of arc_ “became a -quantity to be considered.” Justly arguing, however, that previous -experiments on stellar parallax had been unsatisfactory and indecisive, -he determined to try again. - -He chose the “double star method,” invented by Galileo, but never, so -far, effectually put to trial. The principle of it is perfectly simple, -depending upon the perspective shifting to a spectator in motion, of -objects at different distances from him. In order to apprehend it, -one need only walk up and down before a lamp placed in the middle of -a room, watching its apparent change of position relative to another -lamp at the end of the same room. Just in the same way, a star observed -from opposite sides of the earth’s orbit is sometimes found to alter -its situation very slightly by comparison with another star close to it -in the sky, but indefinitely remote from it in space. Half the small -oscillation thus executed is called that star’s “annual parallax.” It -represents the minute angle under which the radius of the terrestrial -orbit would appear at the star’s actual distance. So vast, however, is -the scale of the universe, that this tell-tale swing to and fro is, -for the most part, imperceptible even with modern appliances, and was -entirely inaccessible to Herschel’s observations. Yet they did not -remain barren of results. - -“As soon as I was fully convinced,” he wrote in 1781, “that in the -investigation of parallax the method of double stars would have many -advantages above any other, it became necessary to look out for proper -stars. This introduced a new series of observations. I resolved to -examine every star in the heavens with the utmost attention that I -might fix my observations upon those that would best answer my end. -The subject promises so rich a harvest that I cannot help inviting -every lover of astronomy to join with me in observations that must -inevitably lead to new discoveries. I took some pains to find out -what double stars had been recorded by astronomers; but my situation -permitted me not to consult extensive 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.” - -On January 10th, 1782, he presented to the Royal Society a catalogue -of 269 double stars, of which 227 were of his own finding; and a -second list of 434 followed in December, 1784. All were arranged in -six classes, according to the distance apart of their components, -ranging from one up to 120 seconds. The close couples he regarded as -especially adapted for parallax-determinations; the wider ones might -serve for criteria of stellar proper movements, or even of the sun’s -transport through space. For the purpose of measuring the directions -in which their members lay towards each other--technically called -“position-angles”--and the intervals separating them, he invented -two kinds of micrometers, and notes were added as to their relative -brightness and colours. He was the first to observe the lovely -contrasted or harmonised tints displayed by some of these objects. - -Herschel’s double stars actually fulfilled none of the functions -assigned to them. He was thus left without any definite unit of -measurement for sidereal space; and he never succeeded in supplying the -want. In 1814 he was “still engaged,” though vainly, “in ascertaining -a scale whereby the extent of the universe, so far as it is possible -for us to penetrate into space, may be fathomed.” He knew only that -the distances of the stars nearest the earth could not be less, and -might be a great deal more, than light-waves, propagated at the rate -of 186,300 miles a second, would traverse in three or four years. Only -the _manner_ of stellar arrangement, then, remained open to his zealous -investigations. - -The initial question presenting itself to an intelligent spectator of -the nocturnal sky is: What relation does the dim galactic star-stream -bear to the constellations amidst which it flows? And this question -our interior position makes very difficult to be answered. We see -the starry universe, it has been well said, “not in _plan_ but in -_section_.” The problem is, from that section to determine the plan--to -view the whole mentally as it would show visually from the outside. The -general appearance to ourselves of the Milky Way leaves it uncertain -whether it represents the projection upon the heavens of an immense -stratum of equally scattered stars, or a ring-like accumulation, -towards the middle of which our sun is situated. Herschel gave his -preference, to begin with, to the former hypothesis, and then, with -astonishing boldness and ingenuity, attempted to put it experimentally -to the proof. - -His method of “star-gauging” was described in 1784. It consisted in -counting the stars visible in successive fields of his twenty-foot -telescope, and computing the corresponding depths of space. Admitting -an average regularity of distribution, this was easily done. If the -stars did not really lie closer together in one region than in another, -then the more of them there were to be seen along a given line of -vision, the further the system could be inferred to extend in that -particular direction. The ratio of its extension would also be given. -It would vary with the cube-roots of the number of stars in each count. - -Guided by this principle, Herschel ventured to lay down the boundaries -of the stellar aggregation to which our sun belongs. So far as he -“had yet gone round it,” in 1785, he perceived it to be “everywhere -terminated, and in most places very narrowly too.” The differences, -however, between his enumerations in various portions of the sky -were enormous. In the Milky Way zone the stars presented themselves -in shoals. He met fields--of just one quarter the area of the -moon--containing nearly 600; so that, in fifteen minutes, 116,000 -were estimated to have marched past his stationary telescope. Here, -the calculated “length of his sounding-line” was nearly 500 times the -distance of Sirius, his standard star. Towards the galactic poles, on -the contrary, stars were comparatively scarce; and the transparent -blackness of the sky showed that in those quarters the supply of -stars was completely exhausted. At right angles to the Milky Way, -then, the stellar system might be termed shallow, while in its plane, -it stretched out on all sides to an inconceivable, though not to an -illimitable extent. Its shape appeared, accordingly, to be that of a -flat disc, of very irregular contour, and with a deep cleft matching -the bifid section of the Milky Way between Cygnus and Scorpio. - -Herschel regarded this conclusion only “as an example to illustrate -the method.” Yet it was derived from the reckoning-up of 90,000 stars -in 2,400 telescopic fields! Its validity rested on the assumption -that stellar crowding indicated, not more stars in a given space, but -more space stocked in the same proportion with stars. But his hope -of thus getting a true mean result collapsed under the weight of his -own observations. “It would not be difficult,” he stated in 1785, “to -point out two or three hundred gathering clusters in our system.” The -action of a “clustering power” drawing its component stars “into many -separate allotments” grew continually clearer to him, and he admitted -unreservedly in 1802 that the Milky Way “consists of stars very -differently scattered from those immediately about us.” - -In 1811, he expressly abandoned his original hypothesis. “I must freely -confess,” he wrote, “that by continuing my sweeps of the heavens -my opinion of the arrangement of the stars has undergone a gradual -change. An equal scattering of the stars may be admitted in certain -calculations; but when we examine the Milky Way, or closely compressed -clusters, it must be given up.” - -And in 1817: “Gauges, which on a supposition of an equality of -scattering, were looked upon as gauges of distance, relate, in fact, -more immediately to the scattering of the stars, of which they give -valuable information.” - -The “disc-theory” was then virtually withdrawn not many years after it -had been propounded. “The subtlety of nature,” according to Bacon’s -aphorism, “transcends the subtlety both of the intellect and of the -senses.” Herschel very soon perceived the inadequacy of his colossal -experiment; and he tranquilly acquiesced, not being among those who -seek to entrench theory against evidence. He found that he had -undervalued the complexity of the problem. Yet it remained before his -mind to the end. The supreme object of his scientific life was to -ascertain the laws of stellar distribution in cubical space, and he -devoted to the subject the two concluding memoirs of the sixty-nine -contributed by him to the “Philosophical Transactions.” He was in his -eightieth year when he opened, with youthful freshness, a new phase of -arduous investigation. - -“The construction of the heavens,” he wrote in June, 1817, “can only -be known when we have the situation of each body defined by its three -dimensions. Of these three, the ordinary catalogues give but two, -leaving the distance or profundity undetermined.” This element of -“profundity” he went on to determine by the absolutely novel method of -what may be called “photometric enumeration.” - -He began by asserting what is self-evident--that faint stars are, “one -with another,” more remote than bright ones; and he argued thence, -reasonably enough, that the relative mean distances of the stars, taken -order by order, might be inferred from their relative mean magnitudes. -Next he pointed out that more space would be available for their -accommodation in proportion to the cubes of their mean distances. -Here lies the value of the method. It sets up, as Herschel said, “a -standard of reference” with regard to stellar distribution. It makes it -possible to compare actual stellar density, at a given mean distance, -with a “certain properly modified equality of scattering.” By patiently -calling over the roll of successive magnitudes, information may be -obtained regarding over- and under-populated districts of space. - -Herschel’s reasonings on the subject are perfectly valid, but for -practical purposes far in advance of the time. Their application -demanded a knowledge of stellar light-gradations, which, even now, has -been only partially attained. His surprising anticipation of this mode -of inquiry came, therefore, to nothing. - -His device of “limiting apertures” was a simultaneous invention. It -was designed as a measure of relative star-distances. Pointing two -similar telescopes upon two unequal stars, he equalised them to the -eye by stopping down the aperture of the instrument directed towards -the brighter object. Assuming each to emit the same quantity of light, -their respective distances would then be inversely as the diameters of -the reflecting surfaces by which they were brought to the same level of -apparent lustre. But the enormous real diversities of stellar size and -brightness render this plan of action wholly illusory. Even for average -estimates, proper motion is apparently a safer criterion of distance -than magnitude. - -Herschel employed the method of apertures with better success to -ascertain the comparative extent of natural and telescopic vision. The -boundary of the former was placed at “the twelfth order of distance.” -Sirius, that is to say, removed to twelve times its actual remoteness, -would be a barely discernible object to the naked eye. The same star -carried seventy-five times further away still, could be seen as a faint -light-speck with his twenty-foot telescope; and, transported 192 times -beyond the visual limit, would make a similar appearance in the field -of the forty-foot. These figures, multiplied by twelve, represented, -in his expressive phrase, the “space-penetrating power” of his -instruments. Their range extended respectively to 900 and 2,300 times -the distance of his “standard star.” He estimated, moreover, that, -through the agency of the larger, light might become sensible to the -eye after a journey lasting nearly seven thousand years! So that, as he -said, his telescopes penetrated both time and space. - -His last observation of the Milky Way showed it to be in parts -“fathomless,” even with the forty-foot. No sky-background could be -seen, but only the dim glow of “star-dust.” This effect he attributed -to the immeasurable extension, in those directions, of the stellar -system. The serried orbs composing it, as they lay further and further -from the eye, became at last separately indistinguishable. Herschel, as -has been said, formulated no second theory of galactic structure after -that of 1784–5 had been given up. What he thought on the subject, with -ripened experience for his guide, can only be gathered piecemeal from -his various writings. The general appearance of - - That “broad and ample road, whose dust is gold, - And pavement stars,” - -he described as “that of a zone surrounding our situation in the -solar system, in the shape of a succession of differently condensed -patches of brightness, intermixed with others of a fainter tinge.” -And he evidently considered this _seeming_ to be in fair accord with -reality. The “patches of brightness” stood for genuine clusters, -incipient, visibly forming, or formed. They are made up of stars not -less lustrous, but much more closely collected than Sirius, Arcturus, -or Capella. The smallness of galactic stars would thus be an effect -of distance, while their crowding is a physical fact. The whole of -these clusters are (on Herschel’s view) aggregated into an irregular, -branching ring, distinct from, although bound together into one system -with the brilliants of the constellations. “Our sun,” he emphatically -affirmed in 1817, “with all the stars we can see with the eye, are -deeply immersed in the Milky Way, and form a component part of it.” - -He took leave of the subject which had engrossed so many of his -thoughts in a paper read before the Royal Society, June 11th, 1818. -In it he showed how the “equalising” principle could be applied to -determine the relative distances of “globular and other clusters,” -provided only that their component stars are of the rank of Sirius. -It is improbable, however, that this condition is fulfilled. In open -groups, such as the Pleiades, enormous suns are most likely connected -with minute self-luminous bodies; but the stars compressed into -“globular clusters” appear to be more uniform, and may, perhaps, be -intermediate in magnitude. Yet here again, the only thing certain is -the prevalence of endless variety. Celestial systems are not turned out -by the dozen, like articles from a factory. Each differs from the rest -in scale, in structure, in mechanism. Attempts to reduce all to any -common standard must then prove futile. Disparities of distance are of -course concerned in producing their varieties of aspect, coarse-looking -“balls of stars” being, necessarily, on the whole, less remote than -those of smoother texture. Finer graining, however, may also be due to -a composition out of smaller and closer masses. The two causes concur, -and the share of each in producing a certain effect cannot, in any -individual case, be apportioned. - -Herschel was indeed far too philosophical to adopt rigid lines of -argument. His reasoning did not extend “so far as to exclude a -real difference, not only in the size, but also in the number and -arrangement of the stars in different clusters.” Nevertheless, -the discussion founded upon it is no longer convincing. To modern -astronomers it appears to travel quite wide of the mark. Its interest -consists in the proof given by it that the problem of sidereal -distances, the original incentive to Herschel’s reviews of the -heavens, attracted his attention to the very end of his thinking life. -Throughout his long career, the profundities of the universe haunted -him. He sought, _per fas, per nefas_, trustworthy measures of the -“third dimension” of celestial space. The object of his search was out -of reach, and has not even now been fully attained; but the path it led -him by was strewn with discoveries. - -The nets spread in his “sweeps” brought in, besides double stars, -plentiful takes of the filmy objects called “nebulæ.” He recognised -with amazement their profusion in certain tracts of the sky; increased -telescopic light-grasp never failed to render a further supply visible; -the heavens teemed with them. He presented a catalogue of 1,000 to the -Royal Society in 1786, a second equally comprehensive in 1789, and a -supplementary list of 500 in 1802. Their natural history fascinated -him. What they were, what they had been, and what they should come to, -formed the subject of many of those ardent meditations which supplied -motive power for his researches. He not only laid the foundation of -nebular science, but carried the edifice to a considerable height, -distinguishing the varieties of its objects, and classifying them -according to their gradations of brightness. Some presented a most -fantastic appearance. - -“I have seen,” he wrote in 1784, “double and treble nebulæ variously -arranged; large ones with small, seeming attendants; narrow, but much -extended lucid nebulæ or bright dashes; some of the shape of a fan, -resembling an electric brush, issuing from a lucid point; others of -the cometic shape, with a seeming nucleus in the centre, or like -cloudy stars surrounded with a nebulous atmosphere; a different sort, -again, contained a nebulosity of the milky kind, like that wonderful, -inexplicable phenomenon about Theta Orionis; while others shine with a -fainter mottled kind of light which denotes their being resolvable into -stars.” - -He, “through the mystic dome,” discerned - - “Regions of lucid matter taking form, - Brushes of fire, hazy gleams, - Clusters and beds of worlds, and bee-like swarms - Of suns and starry streams.” - -Annular and planetary nebulæ were _as such_, first described by him. -“Among the curiosities of the heavens,” he announced in 1785, “should -be placed a nebula that has a regular concentric dark spot in the -middle, and is probably a ring of stars.” This was the famous annular -nebula in Lyra, then a unique specimen, now the type of a class. - -The planetary kind, so-called from their planet-like discs, were -always more or less of an enigma to him. The vividness and uniformity -of their light appeared to cut them off from true nebulæ; on mature -consideration, he felt driven to suppose them “compressed star-groups.” -“If it were not, perhaps, too hazardous,” he went on, “to pursue -a former surmise of a renewal in what I figuratively called the -laboratories of the universe, the stars forming these extraordinary -nebulæ, by some decay or waste of nature, being no longer fit for their -former purposes, and having their projectile forces, if any such they -had, retarded in each other’s atmospheres, rush at last together, and -either in succession, or by one general tremendous shock, unite into a -new body. Perhaps the extraordinary and sudden blaze of a new star in -Cassiopeia’s Chair, in 1572, might possibly be of such a nature.” - -At that early stage of his inquiries, Herschel regarded all nebulæ -indiscriminately as composed of genuine stars. It was almost inevitable -that he should do so. For each gain in telescopic power had the effect -of transferring no insignificant proportion of them from the nebular -to the stellar order. There was no apparent reason for drawing a line -anywhere. The inference seemed irresistible, that resolvability was -simply a question of optical improvement. As Messier’s _nébuleuses sans -étoiles_ had yielded to Herschel’s telescopes, so--it might fairly -be anticipated--the “milky” streaks and patches seen by Herschel -would curdle into stars under the compulsion of the still mightier -instruments of the future. He was led on--to use his own expressions -in 1791--“by almost imperceptible degrees from evident clusters, -such as the Pleiades, to spots without a trace of stellar formation, -the gradations being so well connected as to leave no doubt that all -these phenomena were equally stellar.” They were what Lambert and Kant -had supposed them to be--island-universes, vast congeries of suns, -independently organised, and of galactic rank. They were, each and all, -glorious systems, barely escaping total submergence in the illimitable -ocean of space. Under the influence of these grandiose ideas, Herschel -told Miss Burney, in 1786, that with his “large twenty-foot” he had -“discovered 1,500 universes!” Fifteen hundred “whole sidereal systems, -some of which might well outvie our Milky Way in grandeur.” - -His contemplations of the heavens showed him everywhere traces of -progress--of progress rising towards perfection, then sinking into -decay, though with a sure prospect of renovation. He was thus led to -arrange the nebulæ in a presumed order of development. The signs of -interior condensation traceable in nearly all, he attributed to the -persistent action of central forces. Condensation, then, gave evidence -of age. Aggregated stars drew closer and closer together with time. So -that scattered or branching formations were to be regarded as at an -early stage of systemic existence; globular clusters, as representing -universes still in the prime of life; while objects of the planetary -kind were set down as “very aged, and drawing on towards a period of -change, or dissolution.” - -Our own nebula he characterised as “a very extensive, branching -congeries of many millions of stars,” bearing upon it “fewer marks of -profound antiquity than the rest.” Yet, in certain regions, he found -“reason to believe that the stars are now drawing towards various -secondary centres, and will in time separate into different clusters.” -As an example of the ravages of time upon the galactic structure, -he adverted to a black opening, four degrees wide, in the Zodiacal -Scorpion, bordered on the west by an exceedingly compact cluster -(Messier’s No. 80), possibly formed, he thought, of stars drawn from -the adjacent vacancy. The chasm was to him one of the most impressive -of celestial phenomena. His sister preserved an indelible recollection -of hearing him, in the course of his observations, after a long, awful -silence, exclaim, “Hier ist wahrhaftig ein Loch im Himmel!” (Here, -truly, is a hole in the sky); and he recurred to its examination -night after night and year after year, without ever clearing up, to -his complete satisfaction, the mystery of its origin. The cluster -significantly located at its edge was lit up in 1860 by the outburst of -a temporary star. - -This was not the sole instance noted by Herschel of the conjunction -of a chasm with a cluster; and chasms and clusters alike told the -same story of dilapidation. He foresaw, accordingly, as inevitable, -the eventual “breaking-up” of the Milky Way into many small, but -independent nebulæ. “The state into which the incessant action of the -clustering power has brought it at present,” he wrote in 1814, “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 -for ever, it equally bears witness that its past duration cannot be -admitted to be infinite.” - -Thus the idea of estimating the relative “ages” of celestial -objects--of arranging them according to their progress in development, -originated with Herschel in 1789. “This method of viewing the heavens,” -he added, “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?” - -But while he followed the line of continuity thus vividly traced, -another crossing, and more or less interfering with it, opened out -before him. The discovery of a star in Taurus, “surrounded with a -faintly luminous atmosphere,” led him, in 1791, to revise his previous -opinions regarding the nature of nebulæ. He was not at all ashamed of -this fresh start. No fear of “committing himself” deterred him from -imparting the thoughts that accompanied his multudinous observations. -He felt committed to nothing but truth. He was advancing into an -untrodden country. At every step he came upon unexpected points of -view. The bugbear of inconsistency could not prevent him from taking -advantage of each in turn to gain a wider prospect. - -Until 1791 Herschel never doubted that gradations of distance fully -accounted for gradations of nebular resolvability. He had been led on, -he explained, by almost imperceptible degrees from evident clusters -to spots without a trace of stellar formation, no break anywhere -suggesting the possibility of a radical difference of constitution. -“When I pursued these researches,” he went on, “I was in the situation -of a natural philosopher who follows the various species of animals -and insects from the height of their perfection down to the lowest ebb -of life; when, arriving at the vegetable kingdom, he can scarcely point -out to us the precise boundary where the animal ceases and the plant -begins; and may even go so far as to suspect them not to be essentially -different. But, recollecting himself, he compares, for instance, -one of the human species to a tree, and all doubt upon the subject -vanishes. In the same manner we pass by gentle steps from a coarse -cluster to an object such as the nebula in Orion, where we are still -inclined to remain in the once adopted idea of stars exceedingly remote -and inconceivably crowded, as being the occasion of that remarkable -appearance. It seems, therefore, to require a more dissimilar object -to set us right again. A glance like that of the naturalist, who casts -his eye from the perfect animal to the perfect vegetable, is wanting -to remove the veil from the mind of the astronomer. The object I have -mentioned above is the phenomenon that was wanting. View, for instance, -the nineteenth cluster of my sixth class, and afterwards cast your eye -on this cloudy star, and the result will be no less decisive than that -of the naturalist. Our judgment, I venture to say, will be that _the -nebulosity about the star is not of a starry nature_.” - -In this manner he inferred the existence of real nebulous matter--of -a “shining fluid” of unknown and unimaginable properties. Was it -perhaps, he asked himself, a display of electrical illumination, like -the aurora borealis, or did it rather resemble the “magnificent cone of -the zodiacal light?” A boundless field of speculation was thrown open. -“These nebulous stars,” he added, “may serve as a clue to unravel -other mysterious phenomena.” - -As their close allies, he now recognised planetary nebulæ, the -“milkiness, or soft tint of their light,” agreeing much better with the -supposition of a fluid, than of a stellar condition. And he rightly -placed in the same category the Orion nebula, and certain “diffused -nebulosities” which he had observed just to tarnish the sky over wide -areas. These last might, he considered, be quite near the earth, and -the object in Orion not more distant than perhaps an average second -magnitude star. - -The relations of the sidereal to the nebular “principle” exercised -Herschel’s thoughts during many years. He had no sooner reasoned out -the existence in interstellar space of a rarefied, self-luminous -substance, than he began to interrogate himself as to its probable -function. Nature was to him the expression of Supreme Reason. He could -only conceive of her doings as directed towards an intelligible end. -Hence his confidence that rational investigation must lead to truth. - -Already in 1791 he hinted at the conclusion which he foresaw. The -envelope of a “cloudy star” was, he declared, “more fit to produce -a star by its condensation than to depend upon the star for its -existence.” And the surmise was confirmed by his detection, in a -planetary nebula, of a sharp nucleus, or “generating star,” possibly to -be completed in time by the further accumulation of luminous matter. - -His conjectures developed in 1811 into a formal theory. The cosmical -fluid was met with in all stages of condensation. Nebulous tracts of -almost evanescent lustre were connected in an unbroken series with -slightly “burred” objects, wanting only a few last touches to make them -finished stars. The extremes, as he said, had been, by his “critical -examination of the nebulous system,” “connected by such nearly allied -intermediate steps, as will make it highly probable that every -succeeding state of the nebulous matter is the result of the action of -gravitation upon it while in a foregoing one.” - -In 1814 he traced the progress towards maturity of binary systems. -Originating in double nebulæ incompletely dissevered--Siamese-twin -objects, of which he had collected 139 examples--they next appeared -as nebulously-connected stars, finally as a pair materially isolated, -and linked together by the sole tie of gravitation. Scattered clusters -represented, in his scheme of celestial progress, a state antecedent -to that of globular clusters. “The still remaining irregularity of -their arrangement,” he said, “additionally proves that the action of -the clustering power has not been exerted long enough to produce a more -artificial construction.” He made, too, the important admission that -clusters apparently “in, or very near the Milky Way,” were truly part -and parcel of that complex agglomeration. - -But what of his “fifteen hundred universes,” which had now logically -ceased to exist? The stellar and nebular “principles” had virtually -coalesced; both were included in the galactic system. The question -of “island universes” was accordingly left in abeyance; although -Herschel certainly believed in 1818 that among the multitude of -“ambiguous objects”--we should call them irresolvable nebulæ--many -exterior firmaments were included. Yet what he had ascertained about -the distribution of nebulæ should alone have sufficed to shatter this -remnant of a conviction. - -The fact became clear to him during the progress of his “sweeps” that -nebulæ, to some extent, _replace stars_. He found them to occur in -“parcels,” more or less embedded with stars, “beds” and “parcels” -together being surrounded by blank spaces. This arrangement grew so -familiar to him that he used to notify his assistant, when stars -thinned out in the zone he was traversing, “to prepare for nebulæ.” -A wider relationship, brought within view by the large scale of -his labours, was defined by his fortunate habit of charting, for -convenience of identification, each newly-discovered batch of nebulæ. - -“A very remarkable circumstance,” he wrote in 1784, “attending the -nebulæ and clusters of stars, is that they are arranged into strata, -which seem to run on to a great length; and some of them I have already -been able to pursue, so as to guess pretty well at their form and -direction. It is probable enough that they may surround the whole -apparent sphere of the heavens, not unlike the Milky Way.” - -In the following year he spoke no longer of a zone, but of two vast -groupings of nebulæ about the opposite poles of the Milky Way. That -is to say, where stars are scarcest nebulæ are most abundant. The -correspondence did not escape him; but he did not recognise its -architectonic meaning. He had traced out the main plan of the stellar -world; he had discovered, not merely thousands of nebulæ, but the -nebular system; he had shown that stars and nebulæ were intimately -associated; he had even made it clear that nebular distribution was -governed by the lines of galactic structure. It only remained to draw -the obvious inference that these related parts made up one whole--that -no more than a single universe is laid open to human contemplation. -This was done by Whewell thirty years after his death. - - - - -CHAPTER IV. - -HERSCHEL’S SPECIAL INVESTIGATIONS. - - -Double stars were, when Herschel began to pay attention to them, -regarded as mere chance productions. No suspicion was entertained -that a real, physical bond united their components. Only the Jesuit -astronomer, Christian Mayer, maintained that bright stars were often -attended by faint ones; and since his observations were not such as -to inspire much confidence, his assertions counted for very little. -“In my opinion,” Herschel wrote in 1782, “it is much too soon to form -any theories of small stars revolving round large ones.” He, indeed, -probably even then, suspected that close _equal_ stars formed genuine -couples; but he waited, if so, for evidence of the connection. The -chief subject of his experiments on parallax was Epsilon Boötis, an -exquisitely tinted, unequal pair. But he soon became aware that either -stellar parallax was elusively small, or that he was on the wrong track -for detecting it. And, since his favourite stars have proved to be a -binary combination, it was, of course, drawing water in a sieve to make -one the test of perspective shifting in the other. - -The number of Herschel’s double stars alone showed them to be integral -parts of an express design. Such a crop of casualties was out of all -reasonable question. And it was actually pointed out in 1784 by John -Michell, a man of extraordinary sagacity, that the odds in favour of -their physical union were truly “beyond arithmetic.” - -Herschel meantime kept them under watch and ward, and after the lapse -of a score of years found himself in a position to speak decisively. -On July 1, 1802, he informed the Royal Society that “casual situations -will not account for the multiplied phenomena of double stars,” adding, -“I shall soon communicate a series of observations proving that many -of them have already changed their situation in a progressive course, -denoting a periodical revolution round each other.” A year later he -amply fulfilled this pledge. Discussing in detail the displacements -brought to light by his patient measurements, he made it clear that -they could be accounted for only by supposing the six couples in -question to be “real binary combinations, intimately held together -by the bond of mutual attraction.” His conclusion was, in each case, -ratified by subsequent observation. The stars instanced by him--Castor, -Gamma Leonis, Epsilon Boötis, Delta Serpentis, Gamma Virginis, and -Zeta Herculis--are all noted binaries. Not satisfied with establishing -the fact, Herschel assigned the periods of their revolutions. But he -could only do so on the hypothesis of circular motion, while the real -orbits are highly elliptical. His estimates then went necessarily wide -of the mark. For one pair only, he was able to use an observation -anterior to his own. Bradley had roughly fixed, in 1759, the relative -position of the components of Castor, the finest double star in the -northern heavens; and the preservation of the record in Dr. Maskelyne’s -note-book extended by twenty years the basis of Herschel’s conclusions -regarding this system. - -He continued, in 1803, his discussions of double stars; announced -a leisurely circulation of both the pairs composing the typical -“double-double star,” Epsilon Lyræ; and conjectured the union of the -two into one grand whole--a forecast verified by the evidence of -common proper motion. The Annus Magnus of the quadruple system cannot, -according to Flammarion, be less than a million of years. - -The discovery of binary stars was, in Arago’s phrase, “one with a -future.” In itself an amazing revelation, it marked the beginning of -a series of investigations of immense variety and importance. By it, -a science of sidereal mechanics was shown to be possible; the sway of -gravitation received an unlimited extension; and the perception of -order, which is the precursor of knowledge, ranged at once over the -whole visible creation. Herschel, it is true, had not the means of -formally proving that stellar orbits are described in obedience to the -Newtonian law. His affirmative assertion rested only on the analogy of -the solar system. But the rightness of his judgment has never seriously -been called in question. - -His research into the transport of the solar system through space -proved, as Bessel said, that the activity of his mind was independent -of the stimulus supplied by his own observations. It was one of his -most brilliant performances. - -The detection of progressive star-movements was due to Halley. It -was announced in 1718. The bright objects spangling the sky are then -“fixed” only in name. “But if the proper motion of the stars be -admitted,” asked Herschel, “who can deny that of our sun?” The same -idea had occurred to several earlier astronomers, but only one, Tobias -Mayer, of Göttingen, had tried to test it practically; and he had -failed. “To discern the proper motion of the sun between so many other -motions of the stars,” Herschel might well designate “an arduous task.” -Yet it was not on that account to be neglected. The conditions of the -problem were perfectly clear to him. If the sun alone were in motion, -the stars should unanimously appear to drift backward from the “apex,” -or point on the sphere towards which his journey was directed. The -heavens would open out in front of his advance, and close up behind. -The effect was compared by Mayer to the widening prospect and narrowing -vista of trees to a man walking through a forest. On this supposition, -the perspective displacements of any two stars sufficiently far apart -in the sky would suffice to determine the solar apex. For it should -coincide with the intersection of the two great circles continuing the -directions of those displacements. But the question is far from being -of this elementary nature. The stars are all flitting about on their -own account, after--to our apprehension--a haphazard fashion. The sole -element of general congruity traceable among them is that “systematic, -or higher, parallax,” by which each of them is, according to a -determinate proportion, inevitably affected. If this can be elicited, -the line of the sun’s progress becomes at once known. - -Herschel treated the subject in the simplest possible manner. Striking -a balance between the proper motions of only seven stars, he deduced, -in 1783, from simple geometrical considerations, an apex for the sun’s -way, marked by the star Lambda Herculis. But while he seemed to proceed -by rule, he was really led by the unerring instinct of genius. His -mode of conducting an investigation, small in compass, yet almost -inconceivably grand in import, distances praise. Its directness and -apparent artlessness strike us dumb with wonder. Eminently suited to -the materials at his command, it was summary, yet, within fairly narrow -limits, secure. And the result has stood the test of time. It ranks, -even now, as a valuable approximation to the truth. He himself regarded -his essay as nothing more than an experimental effort. In a letter to -Dr. Wilson, of Glasgow, he expressed his apprehensions lest his paper -on the sun’s motion “might be too much out of the way to deserve the -notice of astronomers.” - -Provided with Maskelyne’s table of thirty-six proper motions, he -resumed the subject in 1805. He now employed a graphical method, -drawing great circles to represent the observed stellar movements, and -planting his apex impartially in the midst of their intersections. It -was, however, less happily located than that of 1783. The constellation -Hercules again just included it; but it lay certainly too far west, -and probably too far north. The memoir conveying the upshot of the -research is, none the less, a masterpiece. Philosophy and common-sense -have rarely been so fortunately blended as in this discussion. Without -any mathematical apparatus, the plan of attack upon a recondite problem -is expounded with the utmost generality and precision. The reasoning -is strong and sure; intelligible to the ignorant, instructive to the -learned. - -In his earlier paper, Herschel, while venturing only to “offer a few -distant hints” as to the _rate_ of the sun’s travelling, expressed -the opinion that it could “certainly not be less than that which the -earth has in her annual orbit.” That is to say, his minimum estimate -was then nineteen miles per second. A direct inquiry, on the other -hand, convinced him, in 1806, that the solar motion, viewed at right -angles from the distance of Sirius, would cover yearly an arc of -1″. 112. This he called “its quantity;” the corresponding velocity -remained undetermined. We can, however, now, since the real distance -of his assumed station has been determined, translate this angular -value into a linear speed of about nine miles a second. The mean of -his two estimates, or fourteen miles a second, probably differs little -from the actual rate at which the solar system is being borne to its -unimaginable destination. - -His conclusions regarding the solar translation obtained little notice, -and less acceptance from his contemporaries and immediate successors. -His son rejected them as untrustworthy; Bessel, the greatest authority -of his time in the science of “how the heavens move,” declared in -1818 that the sun’s apex might be situated in any other part of the -sky with as much probability as in the constellation Hercules. Not -until Argelander, by a strict treatment of multiplied and improved -data, arrived in 1837 at practically the same result, did Herschel’s -anticipatory efforts obtain the recognition they deserved. Scarcely in -any department has there been put on record so well-directed a leap -into the dark of coming discovery. - -The systematic light-measurement of the stars began with the same -untiring investigator. He described in 1796 the method since named -that of “sequences,” and presented to the Royal Society the first of -six Photometric Catalogues embracing nearly all the 2,935 stars in -Flamsteed’s “British Catalogue.” They gave comparative brightnesses -estimated with the naked eye; classification by magnitudes was put -aside as vague and misleading. The “sequences” serving for their -construction were lists of stars arranged, by repeated trials, in -order of lustre, and rendered mutually comparable by the inclusion -in each of a few members of the preceding series. Their combination -into a catalogue was then easily effected. “Simple as my method is in -principle,” he remarked, “it is very laborious in its progress.” On a -restricted scale it is still employed for following the gradations of -change in variable stars. - -These researches lay, as Professor Holden expresses it, “directly on -the line of Herschel’s main work.” The separation of the stars into -light-ranks intimates at once something as to their distribution in -space; but the intimations may prove deceptive unless the divisions be -accurately established. Hence, stellar photometry is an indispensable -adjunct to the study of sidereal construction. Herschel prosecuted -the subject besides with a view to ascertaining the constancy of -stellar lustre. He had been struck with singular discordances between -magnitudes assigned at different dates. Not to mention stars obviously -variable, there were others which seemed to be affected by a slow, -secular waxing or waning. In some of the instances alleged by him, -the alteration was no doubt fictitious--a record of antique errors; -but there was a genuine residuum. Thus, the immemorially observed -constituents of the Plough preserve no fixed order of relative -brilliancy, now one, now another of the septett having, at sundry -epochs, assumed the primacy; while a small star in the same group, -Alcor, the “rider” of the second “horse,” has, in the course of a -millennium, plainly thrown off some part of its former obscurity. The -Arabs in the desert regarded it as a test of penetrating vision; and -they were accustomed to oppose “Suhel” to “Suha” (Canopus to Alcor) as -occupying respectively the highest and lowest posts in the celestial -hierarchy. So that _Vidit Alcor, at non lunam plenam_, came to be a -proverbial description of one keenly alive to trifles, but dull of -apprehension for broad facts. Now, however, Alcor is an easy naked-eye -object. One needs not be a “tailor of Breslau,” or a Siberian savage, -to see it. The little star is unmistakably more luminous than of old. - -An inversion of brilliancy between Castor and Pollux, and between the -two leading stars in the Whale, is further generally admitted to have -taken place during the eighteenth century. The prevalence of such -vicissitudes was deeply impressive to Herschel, especially through -their bearing upon the past and future history of our own planet. -“If,” he said, “the similarity of stars with our sun be admitted, how -necessary will it be to take notice of the fate of our neighbouring -_suns_, in order to guess at that of our own. The _star_ which we have -dignified by the name of _Sun_ may to-morrow begin to undergo a gradual -decay of brightness, like Alpha Ceti, Alpha Draconis, Delta Ursæ -Majoris, and many other diminishing stars. It may suddenly increase -like the wonderful star in Cassiopeia, or gradually come on like -Pollux, Beta Ceti, etc. And, lastly, it may turn into a periodical one -of twenty-five days’ duration (the solar period of rotation), as Algol -is one of three days, Delta Cephei of five days, etc.” He found it, -accordingly, “perhaps the easiest way of accounting for past changes -in climate to surmise that our sun has been formerly sometimes more, -sometimes less, bright than it is at present.” Herschel attempted, -in 1798, to analyse star-colours by means of a prism applied to the -eye-glasses of his reflector. Nothing of moment could at that time come -of such experiments; but they deserve to be remembered as a sort of -premonition of future methods of research into the physical condition -of the stars. - -His attention to the sun might have been exclusive, so diligent was -his scrutiny of its shining surface. Many of its peculiarities were -first described by him, and none escaped him, except the “deeper -deep,” or black nucleus of spots, detected by Dawes in 1852. The dusky -“pores” and brilliant “nodules,” the corrugations, indentations, and -ridges; the manifold aspects of spots, or “openings;” their “luminous -shelving sides,” known as penumbræ; were all noted in detail, ranged in -proper order, and studied in their mutual relations. Spots presented -themselves to him as evident depressions in the luminous disc; faculæ, -“so far from resembling torches,” appeared “like the shrivelled -elevations upon a dried apple, extended in length, and most of them -joined together, making waves, or waving lines.” Towards the north and -south, he went on, “I see no faculæ; there is all over the sun a great -unevenness, which has the appearance of a mixture of small points of -an unequal light; but they are evidently a roughness of high and low -parts.” - -His theory of the solar constitution was a development of Wilson’s. -It was clearly conceived, firmly held, and boldly put forward. The -definite picturesqueness, moreover, of the language in which it was -clothed, at once laid hold of the public imagination, and gave it -a place in public favour from which it was dislodged only by the -irresistible assaults of spectrum analysis. - -The sun was regarded by Herschel as a cool dark body surrounded by -an extensive atmosphere made up of various elastic fluids. Its upper -stratum--Schröter named it the “photosphere”--was of cloud-like -composition, and consisted of lucid matter precipitated from the -elastic medium by which it was sustained. Its depth was estimated at -two or three thousand miles, and the nature of its emissions suggested -a comparison with the densest coruscations of the aurora borealis. -Below lay a region of “planetary,” or protective clouds. Dense, opaque, -and highly reflective, “they must add,” he said, “a most capital -support to the splendour of the sun by throwing back so great a share -of the brightness coming to them.” Their movements betrayed the action -of vehement winds; and indeed the continual “luminous decompositions” -producing the radiating shell, with the consequent regeneration of -atmospheric gases beneath, “must unavoidably be attended with great -agitations, such as with us might even be called hurricanes.” The -formation and ascent of “empyreal gas” would cause, when moderate in -quantity, pores, or small openings in the brilliant layers. But should -it happen to be generated in uncommon quantities, “it will burst -through the planetary regions of clouds, and thus will produce great -openings; then, spreading itself above them, it will occasion large -shallows, and, mixing afterwards gradually with other superior gases, -it will promote the increase, and assist in the maintenance of the -general luminous phenomena.” - -The solid globe thus girt round with cloud and fire was depicted as -a highly eligible place of residence. An equable climate, romantic -scenery, luxuriant vegetation, smiling landscapes, were to be found -there. It might, accordingly, be admitted without hesitation that “the -sun was richly stored with inhabitants.” For the lucid shell visible -from the exterior possessed, according to this theory, none of the -all-consuming ardour now attributed to it. Its blaze was a superficial -display; beneath, “the immense curtain of the planetary clouds was -everywhere closely drawn” round a world perfectly accommodated to vital -needs. - -In order to reconcile this supposed state of things with the observed -order of nature, it was suggested that traces of it subsist in the -planets, “all of which, we have pretty good reason to believe, emit -light in some degree.” The night-side illumination of Venus, the -sinister glare of the eclipsed moon, the auroral glimmerings of the -earth, were adduced as evidence to this effect. The contrast between -the central body and its dependants was softened down to the utmost. - -“The sun, viewed in this light,” Herschel wrote in 1794, “appears to be -nothing else than a very eminent, large, and lucid planet, evidently -the first, or, in strictness of speaking, the only primary one of our -system; all others being truly secondary to it. Its similarity to the -other globes of the solar system with regard to its solidity, its -atmosphere, and its diversified surface; the rotation upon its axis, -and the fall of heavy bodies, lead us on to suppose that it is also -most probably inhabited, like the rest of the planets, by beings whose -organs are adapted to the peculiar circumstances of that vast globe.” - -To us, nearing the grey dawn of the twentieth century, the idea seems -extravagant; it was, in the eighteenth, plausible and alluring. The -philosophers of that age regarded the multiplicity of inhabited -worlds as of axiomatic certainty. The widest possible diffusion of -life followed, they held, as a corollary from the beneficence of the -Creator; while their sense of economy rendered them intolerant of -_wasted_ globes. Herschel was then reluctant to attribute to the sun -a purely _altruistic_ existence. Only from the point of view of our -small terrestrial egotism could so glorious a body figure as solely -an attractive centre, and a focus of warmth and illumination to a -group of planets. Besides, looking abroad through the universe, we see -multitudes of stars which can exercise no ministerial functions. Those -united to form compressed clusters, or simply joined in pairs, are -unlikely, it was argued, to carry a train of satellites with them in -their complex circlings. Unless, then, “we would make them mere useless -brilliant points,” they must “exist for themselves,” and claim primary -parts in the great cosmical life-drama. - -Herschel’s sun is to us moderns a wholly fabulous body. Still, there -is a fantastic magnificence about the conception so strongly realised -by his powerful imagination. Moreover, its scientific value was by -no means inconsiderable. It represented the first serious effort to -co-ordinate solar phenomena; it implied the spontaneous action of some -sort of machinery for the production of light and heat. Spots were -associated with a circulatory process; the photosphere was portrayed -under its true aspect. The persistence of its hollows and heights, its -pores and rugosities, convinced Herschel that the lustrous substance -composing it was “neither a liquid nor an elastic fluid,” which should -at once subside into an unbroken level. “It exists, therefore,” he -inferred, “in the manner of lucid clouds swimming in the transparent -atmosphere of the sun.” - -“The influence of this eminent body on the globe we inhabit,” he wrote, -continuing the subject in 1801, “is so great, and so widely diffused, -that it becomes almost a duty to study the operations which are carried -on upon the solar surface.” This duty he fulfilled to perfection. His -telescopic readings from the changeful solar disc were of extraordinary -precision and comprehensiveness. They show his powers as an observer -perhaps at their best. And, since reasoning was with him inseparable -from seeing, the appearances he noted took, as if of their own accord, -their proper places. The history of spots was completely traced. He -recorded their birth by the enlargement of pores; their development -and sub-division; established their connexion with faculous matter, -piled up beside them like mountain-ranges round an Alpine lake, or -flung across their cavities like blazing suspension-bridges; and -watched finally their closing-up and effacement, not even omitting the -post-mortem examination of the disturbances they left behind. - -One of Herschel’s curiously original enterprises was his attempt to -ascertain a possible connexion between solar and terrestrial physics. -“I am now much inclined to believe,” he stated in 1801, “that openings -with great shallows, ridges, nodules, and corrugations, may lead us to -expect a copious emission of heat, and, therefore, mild seasons. And -that, on the contrary, pores, small indentations, and a poor appearance -of the luminous clouds, the absence of ridges and nodules, and of -large openings and shallows, will denote a spare emission of heat, -and may induce us to expect severe seasons. A constant observation -of the sun with this view, and a proper information respecting the -general mildness or severity of the seasons in all parts of the world, -may bring this theory to perfection, or refute it, if it be not well -founded.” - -But the available data regarding weather-changes turning out to be -exceedingly defective, he had recourse to the celebrated expedient of -comparing the state of the sun in past years with the recorded prices -of corn. Fully admitting the inadequacy of the criterion, he still -thought that the sun being “the ultimate fountain of fertility, the -subject may deserve a short investigation, especially as no other -method is left for our choice.” He obtained, as the upshot, partial -confirmation of the surmise that “some temporary defect of vegetation” -ensued upon the subsidence of solar agitation. In plainer language, -food-stuffs tended to become dear when sun-spots were few and small. No -signs of cyclical change could, however, be made out. The discovery of -the “sun-spot period” was left to Schwabe. This admirable preliminary -effort to elicit the earth’s response to solar vicissitudes was -denounced by Brougham as a “grand absurdity;” and the readers of the -second number of the _Edinburgh Review_ were assured that “since the -publication of ‘Gulliver’s Travels,’ nothing so ridiculous had ever -been offered to the world!” - -Herschel did not neglect the planets. His observations of Venus -extended from 1777 to 1793. Their principal object was to ascertain the -circumstances of the planet’s rotation; but they eluded him; which, -considering that they are still quite uncertain, is not surprising. -He would probably have communicated nothing on the subject had he not -been piqued into premature publication by Schröter’s statement that -the mountains of Venus rose to “four, five, or even six times the -perpendicular elevation of Chimborazo.” Herschel did not believe in -them, and expressed his incredulity in somewhat sarcastic terms. “As to -the mountains in Venus,” he wrote, “I may venture to say that no eye -which is not considerably better than mine, or assisted by much better -instruments, will ever get a sight of them.” He rightly inferred, -however, the presence of an extensive atmosphere from the bending of -the sun’s rays so as to form much more than a semicircular rim of light -to the dark disc of the planet when near inferior conjunction--that is, -when approximately in a right line between us and the sun. He fully -ascertained, too, the unreality of the Cytherean phantom-satellite. -The irritability visible in this paper made a solitary exception -to Herschel’s customary geniality. It might have led to a heated -controversy but for the excellent temper of Schröter’s reply. - -Although we may not be prepared to gainsay Herschel’s dictum that “the -analogy between Mars and the earth is perhaps by far the greatest in -the whole solar system,” we can hardly hold it to be so probable as he -did that “its inhabitants enjoy a situation in many respects similar -to ours.” Yet the modern epoch in the physical study of Mars began -with his announcement in 1784 that its white polar caps spread and -shrank as winter and summer alternated in their respective hemispheres. -His conclusion of their being produced by snowy depositions from -“a considerable, though moderate, atmosphere,” is not likely to be -overthrown. He established, besides, the general permanence of the dark -markings, notwithstanding minor alterations due, he supposed, to the -variable distribution of clouds and vapours on the planet’s surface. - -This vigilant “watcher of the skies” laid before the Royal Society, -May 6th, 1802, his “Observations of the two lately discovered Bodies.” -These were Ceres and Pallas, which, with Juno and Vesta, picked up -shortly afterwards, constituted the vanguard of the planetoid army. -Herschel foresaw its arrival. He adopted unhesitatingly Olbers’s theory -of their disruptive origin, and calculated that Mercury, the least -of the true planets, might be broken up into 35,000 masses no larger -than Pallas. An indefinite number of such fragments (about 420 are -now known) were accordingly inferred to circulate between the orbits -of Mars and Jupiter. He distinguished their peculiarities, and, since -they could with propriety be designated neither planets nor comets, he -proposed for them the name of “asteroids.” But here again he incurred, -to use his own mild phrase, “the illiberal criticism of the _Edinburgh -Review_.” “Dr. Herschel’s passion for coining words and idioms,” -Brougham declared, “has often struck us as a weakness wholly unworthy -of him. The invention of a name is but a poor achievement in him who -has discovered whole worlds.” The reviewer forgot, however, that new -things will not always fit into the framework of old terminology. He -added the contemptible insinuation that Herschel had devised the word -“asteroid” for the express purpose of keeping Piazzi’s and Olbers’s -discoveries on a lower level than his own of Uranus. - -Herschel made no direct reply to the attack; only pointing out, in -December, 1804, how aptly the detection of Juno had come to verify his -forecasts. “The specific differences,” he said, “between planets and -asteroids appear now, by the addition of a third individual of the -latter species, to be more fully established; and that circumstance, -in my opinion, has added more to the ornament of our system than the -discovery of another planet could have done.” - -His endeavours to determine the diameters of these small bodies were -ineffectual. Although he at first estimated those of Ceres and Pallas -at 162 and 147 miles, he admitted later his inability to decide as to -the reality of the minute discs shown by them; and they were first -genuinely measured by Professor Barnard with the great Lick refractor -in 1894. - -The “trade-wind theory” of Jupiter’s belts originated with Herschel; -and he took note of the irregular drifting movements of the spots on -his surface, and their consequent uselessness for determining the -period of his rotation. That of Saturn’s he fixed quite accurately -at ten hours sixteen minutes, with a marginal uncertainty of two -minutes, the period now accepted being of ten hours fourteen minutes. -The possession by this planet of a profound atmosphere was inferred -from the changes in its belts, as well as from some curious phenomena -attending the disappearance of its satellites. They were commonly -seen to “hang on the limb”--that is, to pause during an appreciable -interval on the brink of occultation. Mimas, on one occasion, remained -thus poised during twenty minutes! For so long it was geometrically -concealed, although visible by the effect of refraction. Saturn was -an object of constant solicitude at Slough; and it was only with the -surpassing instruments mounted there that much could be learned about -Galileo’s _altissimo pianeta_. Herschel supposed, with Laplace, the -rings to be solid structures; and he added that the interval of 2,500 -miles separating them “must be of considerable service to the planet -in reducing the space that is eclipsed by the shadow of the ring.” The -“crape ring” was _seen_, but not recognised. In one of his drawings it -figures as a dusky belt crossing the body of the planet. - -His satellite discoveries proved exceedingly difficult to verify. The -Saturnian pair were lost, after he left them, until his son once more -drew them from obscurity. Regarding the outermost member of the system, -Japetus, discovered by Cassini in 1671, Herschel noticed, in 1792, a -singular circumstance. It was already known to vary in brightness; we -receive from it, in fact, four and a-half times more light at certain -epochs than at others. The novelty consisted in showing that this -variation depended upon the satellite’s situation in its orbit in such -a manner as to leave no doubt that, like our moon, it keeps the same -face always directed inwards towards its primary. So that Japetus was -inferred to turn on its axis in the period of its revolution round -Saturn, that is, in seventy-nine and one-third days. - -“From its changes” he “concluded that by far the largest part of its -surface reflects much less light than the rest; and that neither the -darkest nor the brightest side of the satellite is turned towards the -planet, but partly the one and partly the other.” - -Guessing at once that our moon and Japetus did not present the -only examples of equality in the times of rotation and revolution, -he continued: “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 secondaries 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 upon such a construction of their -figure as makes them more ponderous towards their primary planet.” -This very explanation was long afterwards adopted by Hansen. The -peculiarity in question may without hesitation be set down as an effect -of primordial tides. - -In 1797 Herschel brought forward detailed evidence to shew that his -generalisation applied to the Jovian system; but recent observations at -Lick and Arequipa demand a suspension of judgment on the point. - -The Uranian train of attendants was left by Herschel in an unsettled -condition. Two of them, as we have seen, he discovered in 1787; and -he subsequently caught glimpses of what he took to be four others. -But only Oberon and Titania have maintained their status; the four -companions assigned to them are non-existent. An unmistakable interior -pair--Ariel and Umbriel--was, however, discovered by Mr. Lassell, at -Malta, in 1851; and they may possibly have combined with deceptive -star-points to produce Herschel’s dubious quartette. He described in -1798 the exceptional arrangement of the Uranian system. Its circulation -is retrograde. The bodies composing it move from east to west, but in -orbits so tilted as to deviate but slightly from perpendicularity to -the plane of the ecliptic. - -No trifling sensation was created in 1783, and again in 1787, by the -news that Herschel had seen three lunar volcanoes in violent eruption. -“The appearance of the actual fire” in one of them was compared by him -to “a small piece of burning charcoal when it is covered with a very -thin coating of white ashes. All the adjacent parts of the volcanic -mountain seemed to be faintly illuminated by the eruption, and were -gradually more obscure as they lay at a greater distance from the -crater.” He eventually became aware that his senses had imposed upon -him; but the illusion was very complete and has since occasionally been -repeated. What was really seen was probably the vivid reflection of -earth-shine from some unusually white lunar summits. - -He never knowingly discovered a comet, although some few such bodies -possibly ensconced themselves, under false pretences, in his lists -of nebulæ. But he made valuable observations upon the chief of those -visible in his time, and introduced the useful terms, corresponding to -instructive distinctions, “head,” “nucleus,” and “coma.” He inferred -from the partial phases of the comet of 1807, that it was in a measure -self-luminous; and from their total absence in the great comet of 1811, -that its light was almost wholly original. The head of this object, -which shone with an even, planetary radiance, he determined to be -127,000, the star-like nucleus within, 428 miles across. The tail he -described as “a hollow, inverted cone,” one hundred millions of miles -long, and fifteen millions broad. This prodigious appurtenance was, -in grade of luminosity, an exact match for the Milky Way. That comets -wear out by the waste of their substance at perihelion, he thought -very probable; the extent of their gleaming appendages thus serving -as a criterion of their antiquity. They might, indeed, arrive in the -solar system already shorn of much of their splendour by passages round -other suns than ours; but their “age” could, in any case, be estimated -according to the progress made in their decline from a purely nebulous -to an almost “planetary” state. He went so far as to throw out the -conjecture that “comets may become asteroids;” although the converse -proposition that “asteroids may become comets,” of which something has -been heard lately, would scarcely have been entertained by him. - -Enough has been said to show how greatly knowledge of the solar system -in all its parts was furthered by Herschel’s observational resources, -fertility of invention, and indomitable energy. He was, so to speak, -ubiquitous. He had taken all the heavens for his province. Nothing that -they included, from the faintest nebula to the sun, and from the sun to -a telescopic shooting-star, evaded his consideration. A whole cycle of -discoveries and successful investigations began and ended with him. - -His fame as an astronomer has cast into the shade his merits as -a physicist. He made pioneering experiments on the infra-red -heat-rays,[D] and anticipated, by an admirable intuition, the fact -ascertained with the aid of Professor Langley’s “bolometer,” that -the invisible surpass in extent the visible portions of the solar -spectrum.[E] A search for darkening glasses suitable to solar -observations, led him to the inquiry. Finding that some coloured media -transmitted much heat and little light, while others stopped heat and -let through most of the light, he surmised that a different heating -power might belong to each spectral tint. His own maxim that “it is -sometimes of great use in natural philosophy to doubt of things that -are commonly taken for granted,” here came in appropriately. With a -free mind he set about determining the luminous and thermal powers of -successive spectral regions. They seemed to vary quite disconnectedly. -A thermometer exposed to red rays during a given interval, rose three -and a half times as much as when exposed to violet rays; and he showed -further, by tracing the heat- and light-curves of the prismatic -spectrum, that its heat-maximum lay out of reach of the eye in the -infra-red, while luminous intensity culminated in the yellow. He even -threw out the sagacious conjecture that “the chemical properties of -the prismatic colours” might be “as different as those which relate -to light and heat;” adding that “we cannot too minutely enter into -an analysis of light, which is the most subtle of all the active -principles that are concerned in the operations of nature.” - - [D] Phil. Trans. 1800, p. 255. - - [E] _Ibid._, p. 291. - -The ardour with which he pursued the inquiry betrays itself in the -rapid succession of four masterly essays communicated to the Royal -Society in 1800. They contained the first exposition worth mentioning -of the properties of radiant heat. They gave the details of experiments -demonstrating its obedience to the same laws of reflection, refraction, -and dispersion as light; and showing the varieties in the absorptive -action upon it of different substances. In the third memoir of the -series, Professor Holden finds himself at a loss “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.” There -is, indeed, scarcely one of Herschel’s researches in which his -initiative vigour and insight are more brilliantly displayed than in -this _parergon_--this task executed, as it were, out of hours. It is -only a pity that he felt compelled, by the incompatibility of their -distribution in the spectrum, to abandon his original opinion in favour -of the essential identity of light and radiant heat. The erroneous -impression left on the public mind by his recantation has hardly yet -been altogether effaced. - - - - -CHAPTER V. - -THE INFLUENCE OF HERSCHEL’S CAREER ON MODERN ASTRONOMY. - - -The powers of the telescope were so unexpectedly increased, that they -may almost be said to have been discovered by William Herschel. No -one before him had considered the advantages of large apertures. No -one had seemed to remember that the primary function of an instrument -designed to aid vision is to collect light. The elementary principle -of space-penetration had not been adverted to. It devolved upon -him to point out that the distances of similar objects are exactly -proportional to the size of the telescopes barely sufficing to show -them. The reason is obvious. Compare, for instance, a one-inch -telescope with the naked eye. The telescope brings to a focus -twenty-five times as much light as can enter the pupil, taken at -one-fifth of an inch in diameter; therefore it will render visible -a star twenty-five times fainter than the smallest seen without its -help; or--what comes to the same thing--an intrinsically equal star -at a five-fold distance. A one-inch glass hence actually quintuples -the diameter of the visible universe, and gives access to seventy-five -times the volume of space ranged through by the unassisted eye. - -This simple law Herschel made the foundation-stone of his sidereal -edifice. He was the first to notice it, because he was the first -practically to concern himself with the star-depths. The possibility -of gauging the heavens rose with him above the horizon of science. -Because untiring in exploration, he was insatiable of light; and being -insatiable of light, he built great telescopes. - -His example was inevitably imitated and surpassed. Not through a vulgar -ambition to “beat the record,” but because a realm had been thrown open -which astronomers could not but desire to visit and search through for -themselves. Lord Rosse’s six-foot reflector was the immediate successor -of Herschel’s four-foot; Mr. Lassell’s beautiful specula followed; and -the series of large _metallic_ reflectors virtually closed with that of -four-feet aperture erected at Melbourne in 1870. The reflecting surface -in modern instruments is furnished by a thin film of silver deposited -on glass. It has the advantage of returning about half as much again of -the incident light as the old specula, so that equal power is obtained -with less size. Dr. Common’s five-foot is the grand exemplar in this -kind; and it is fully equivalent to the Parsonstown six-foot. - -The improvement of refractors proceeded more slowly. Difficulties -in the manufacture of glass stood in the way, and difficulties in -the correction of colour. The splendid success, however, of the Lick -thirty-six inch, and the fine promise of the Yerkes forty-inch, have -turned the strongest current of hope for the future in the direction of -this class of instrument. But all modern efforts to widen telescopic -capacity primarily derive their impulse from Herschel’s passionate -desire to see further, and to see better, than his predecessors. - -His observations demonstrate the rare excellence of his instruments. -Experiments made on the asteroid Juno, in 1805, for the purpose -of establishing a valid distinction between real and fictitious -star-discs, prove, in Professor Holden’s opinion, the reflector -employed to have been of almost ideal perfection; and his following of -Saturn’s inner satellites right up to the limb, with the twenty-foot -and the forty-foot, was a _tour de force_ in vision scarcely, if ever, -surpassed. - -In the ordinary telescopes of those days really good definition was -unknown; they showed the stars with rays or tails, distorted into -triangles, or bulged into “cocked hats;” clean-cut, circular images -were out of the question. Sitting next Herschel one day at dinner, -Henry Cavendish, the great chemist, a remarkably taciturn man, broke -silence with the abrupt question--“Is it true, Dr. Herschel, that you -see the stars round?” “Round as a button,” replied the Doctor; and no -more was said until Cavendish, near the close of the repast, repeated -interrogatively, “Round as a button?” “Round as a button,” Herschel -briskly reiterated, and the conversation closed. - -It seems probable that Herschel’s _caput artis_ lost some of its -fine qualities with time. Great specula are peculiarly liable to -deterioration. Their figure tends to become impaired by the stress of -their own weight; their lustre is necessarily more or less evanescent. -Re-polishing, however, is a sort of re-making; and the last felicitous -touches, upon which everything depends, can never be reckoned upon with -certainty. Hence, the original faultlessness of the great mirror was, -perhaps, never subsequently reproduced. - -“Such telescopes as Herschel worked with,” Dr. Kitchiner wrote in -1815, “could only be made by the man who used them, and only be used -by the man who made them.” The saying is strictly true. His skill -in one branch promoted his success in the other. He was as much at -home with his telescopes as the Bedouin are with their horses. Their -peculiarities made part of his most intimate experience. From the -graduated varieties of his specula he picked out the one best suited -to the purpose in hand. It was his principle never to employ a larger -instrument than was necessary, agility of movement being taken into -account no less than capacity for collecting light. The time-element, -indeed, always entered into his calculations; he worked like a man who -has few to-morrows. - -His sense of sight was exceedingly refined, and he took care to keep it -so. In order to secure complete “tranquility of the retina,” he used to -remain twenty minutes in the dark before attempting to observe faint -objects; and his eye became so sensitive after some hours spent in -“sweeping,” that the approach of a third-magnitude star obliged him to -withdraw it from the telescope. A black hood thrown over his head while -observing served to heighten this delicacy of vision. He despised no -precaution. Details are “of consequence,” he wrote to Alexander Aubert, -an amateur astronomer, “when we come to refinements, and want to _screw -an instrument up to the utmost pitch_.” - -This was said in reference to his application of what seemed -extravagantly high magnifying powers. He laid great stress upon it in -the earlier part of his career. The method, he said, was “an untrodden -path,” in which “a variety of new phenomena may be expected.” With -his seven-foot Newtonian he used magnifications up to nearly 6,000, -proceeding, however, “all along experimentally”--a plan far too much -neglected in “the art of seeing.” “We are told,” he proceeded, “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.” The innovation was received with a mixture -of wonder, incredulity, and admiration. - -Herschel showed his customary judgment in this branch of astronomical -practice. He established the distinctions still maintained, and -laid down the lines still followed. It is true he went far beyond -the point where modern observers find it advisable to stop. The -highest power brought into use with the Lick refractor is 2,600; and -Herschel’s instruments bore 5,800 (nominally 6,500) without injury to -definition. But only at exceptional moments. His habitual sweeping -power was 460; he “screwed-up” higher only for particular purposes, -and under favourable conditions. Although his strong eye-pieces seem, -for intelligible reasons, to have been laid aside on the adoption of -the “front-view” form of construction, they had served him well in -the division of close pairs, as well as for bringing faint stars into -view--an effect correctly explained by him as due to the augmented -darkness, under high powers, of the sky-ground. But the most important -result of their employment was the discovery that the stars have -no sensible dimensions. This became evident through the failure of -attempts to magnify them; the higher the power applied, the smaller and -more intense they appeared. Herschel accordingly pronounced stellar -telescopic discs “spurious,” but made no attempt to explain their -origin through diffraction. - -He never possessed an instrument mounted equatoreally--that is, so as -automatically to follow the stars. In its absence, his work, had it not -been accomplished, would have seemed to modern ideas impossible. No -clockwork movement kept the objects he was observing in the field of -view. His hands were continually engaged in supplying the deficiency. -How, under these circumstances, he contrived to measure hundreds of -double stars, and secure the places of thousands of nebulæ, would be -incomprehensible but for the quasi-omnipotence of enthusiasm. - -The angle made with the meridian by the line joining two stars (their -“position angle”) was never thought of as a quantity useful to be -ascertained until Herschel, about 1779, invented his “revolving-wire -micrometer.” This differed in no important respect from the modern -“filar micrometer;” only spider-lines have been substituted for the -original silk fibres. For measuring the distances of the wider classes -of double stars, he devised in 1782 a “lamp-micrometer;” while those -of the closest pairs were estimated in terms of the discs of the -components. In compiling his second catalogue, however, he used the -thread-micrometer for both purposes. It is true that “even in his -matchless hands”--in Dr. Gill’s phrase--the results obtained were -“crude;” but the fact remains that the whole system of micrometrical -measurement came into existence through Herschel’s double-star -determinations. - -Their consequences have developed enormously within the last few -years. Mr. Burnham’s discoveries of excessively close pairs have been -so numerous as to leave no reasonable doubt that their indefinite -multiplication is only a question of telescopic possibility. Then -in 1889, another power came into play; the spectroscope took up the -work of resolving stars. Or rather, the spectroscope in alliance -with the photographic camera; for the spectral changes indicating -the direction and velocity of motion in the line of sight can be -systematically studied, as a rule, only when registered on sensitive -plates. The upshot has been to bring within the cognisance of science -the marvellous systems known as “spectroscopic binaries.” They are of -great variety. Some consist of a bright, others of a bright and dark, -pair. Those that revolve in a plane nearly coinciding with our line -of vision undergo mutual occultations. A further detachment seem to -escape eclipse, yet vary in light for some unexplained reason, while -they revolve. Others, like Spica Virginis, revolve without varying. -Their orbital periods are counted by hours or days. The study of the -disturbances of these remarkable combinations promises to open a new -era in astronomical theory. For they are most likely all multiple. -Irregularities indicating the presence of attractive, although obscure -bodies, have, in several cases, been already noticed. - -The revolutions of spectroscopic binary stars can be studied to the -greatest advantage when they involve light-change; and photometric -methods have accordingly begun to play an important part in the -sidereal department of gravitational science. And here again we meet -with Herschel’s initiative. His method of sequences has been already -explained; and he made the first attempt to lay down a definite scale -of star-magnitudes. He failed, and it was hardly desirable that he -should succeed. On his scale, the ratio of change from one grade to the -next constantly diminished. In the modern system it remains always the -same. A star of the second magnitude is by definition two and a-half -(2·512) times less bright than one of the first; a star of the third -magnitude is two and a-half times less bright than one of the second, -the series descending without modification until beyond telescopic -reach. This uniformity in the _proportionate_ value of a magnitude -is indispensable for securing a practicable standard of measurement. -Herschel, however, took the great step of introducing a principle of -order. - -His estimates of stellar lustre were purely visual. And although -various instruments, devised for the purpose, have since proved -eminently useful, the ultimate appeal in all is to the eye. But there -are many signs that, in the photometry of the future, not the eye but -the camera will be consulted. Their appraisements differ markedly. -Herschel’s incidental remark on the disturbance of light-valuation -by colour touches a point of fundamental importance in photographic -photometry. The chemical method gives to white stars a great advantage -over yellow and red ones. They come out proportionately much brighter -on the sensitive plate than they appear to the eye. And to these -varieties of hue correspond spectral class-distinctions, the spectrum -of an object being nothing but its colour written at full length. This -systematic discrepancy between visual and photographic impressions of -brightness, while introducing unwelcome complications in measures of -magnitude, may serve to bring out important truths. The inference, for -example, has been founded upon it that the Milky Way is composed almost -exclusively of white, or “Sirian” stars; and there can be no question -but that the arrangement of stars in space has some respect to their -spectral types. - -Herschel’s plan of inquiry into the laws of stellar distribution by -“photometric enumeration,” or gauging by magnitudes, was a bequest -to posterity which has been turned to account with very little -acknowledgment of its source. Argelander’s review of the northern -heavens (lately completed photographically by Dr. Gill to the southern -pole) afforded, from 1862, materials for its application on a large -scale; but the magnitudes assigned to his 324,000 stars do not possess -the regularity needed to make deductions based on them perfectly -trustworthy. Otherwise the distance from the earth of the actual -aggregations in the Milky Way could have been ascertained in a rough -way from the numerical representation of the various photometric -classes. As it is, the presumption is strong that the galactic clouds -are wholly independent of stars brighter than the ninth magnitude--that -they only begin to gather at a depth in space whence light takes _at -least_ a thousand years to travel to our eyes. Confirmatory evidence, -published in 1894, has been supplied by M. Easton’s research, based on -the same principle, into the detailed relations of stars of various -magnitudes to Milky Way structure. They are exhibited only by those of -the ninth magnitude, or fainter; for with them sets in a significant -crowding upon its condensed parts, attended by a scarcity over its -comparative vacuities. Counts by magnitudes have, besides, made it -clear that the stars, in portions of the sky removed from the Milky -Way, thin out notably before the eleventh magnitude is reached; so -that, outside the galactic zone, the stellar system is easily fathomed. - -Also on the strength of photometric enumerations, Dr. Gould, of Boston, -came to the conclusion, in 1879, that there is an extra thronging of -stars about our sun, which forms one of a special group consisting -of some four or five hundred members. The publication, in 1890, of -the “Draper Catalogue,” of 10,530 photographed stellar spectra, has -thrown fresh light on this interesting subject. Mr. Monck, of Dublin, -gave reasons for holding stars physically like the sun to be generally -nearer to us than stars of the Sirian class; and Professor Kapteyn, of -Gröningen, as the result of a singularly able investigation, concluded -with much probability that the sun belongs to a strongly condensed -group of mostly “solar” stars, nearly concentric with the galaxy. It -might, in fact, be said that we live in a globular cluster, since our -native star-collection should appear from a very great distance under -that distinctive form. - -This modern quasi-discovery was anticipated by Herschel. He was -avowedly indebted, it is true, to Michell’s “admirable idea” of the -stars being divided into separate groups; but Michell did not trouble -himself about the means of its possible verification, and Herschel did. -He always looked round to see if there were not some touchstone of fact -within reach. - -His discussion of the solar cluster, though brief and incidental, is -not without present interest. He found the federative arrangement of -the stars to be “every day more confirmed by observation.” The “flying -synods of worlds” formed by them must gravitate one towards another as -if concentrated at their several centres of gravity. Accordingly, “a -star, or sun, such as ours, may have a proper motion within its own -system of stars, while the whole may have another proper motion totally -different in quantity and direction.” We may thus, he continued, -“arrive in process of time, at a knowledge of all the real, complicated -motions of the planet we inhabit; of the solar system to which it -belongs; and even of the sidereal system of which the sun may possibly -be a member.” He proceeded to explain how stars, making part of the -solar cluster, might be discriminated from those exterior to it; the -former showing the perspective influence only of the sun’s translation -among themselves, while the latter would be affected besides by a -“still remoter parallax”--a secular drift, compounded of the proper -motion of the sun within its cluster, and of its cluster relatively to -other clusters. - -The possibility of applying Herschel’s test is now fully recognised. -Each fresh determination of the solar apex is scrutinised for symptoms -of the higher “systematical parallax;” although as yet with dubious -or negative results. Associated stellar groups are, nevertheless, met -with in various parts of the sky. Herschel not only anticipated their -existence, but suggested “a concurrence of proper motions” as the -fittest means for identifying them. - -His anticipation has been realised by Mr. Proctor’s detection of -“star-drift.” Several stars in the Plough thus form a squadron sailing -the same course; and similar combinations, on an apparently smaller -scale, have been pieced together in various constellations. But the -principle of their connection has yet to be discovered. They are -evidently not self-centred systems; hence their companionship, however -prolonged, must finally terminate. The only pronounced cluster with a -common proper motion is the Pleiades; and its drift seems to be merely -of a perspective nature--a reflection of the sun’s advance. - -Bessel said of Herschel that “he aimed at acquiring knowledge, not of -the motions, but of the constitution of the heavenly bodies, and of -the structure of the sidereal edifice.” This, however, is a defective -appreciation. He made, indeed, no meridian observations, and computed -no planetary or cometary perturbations; yet if there ever was an -astronomer who instinctively “looked before and after,” it was he. -Could he have attained to a complete knowledge of the architecture -of the heavens, as they stood at a given moment, it would not have -satisfied him. To interpret the past and future by the present was his -constant aim; from his “retired situation” on the earth, he watched -with awe the grand procession of the sum of things defile through -endless ages. He could not observe what was without at the same time -seeking to divine what had been, and to forecast what was to come. - -His nebular theory is now accepted almost as a matter of course. The -spectroscope has lent it powerful support by proving the _de facto_ -existence of the “lucid medium,” postulated by him as a logical -necessity. This was done August 1st, 1864, when Dr. Huggins derived -from a planetary nebula in Draco a spectrum characteristic of a gaseous -body, because consisting of bright lines. Their wave-lengths, which -turned out to be identical for all objects of the kind, with one or -two possible exceptions, indicated a composition out of hydrogen -mixed with certain unfamiliar aeriform substances. Herschel’s visual -discrimination of gaseous nebulæ was highly felicitous. Modern science -agrees with him in pronouncing the Orion nebula, as well as others -of the irregular class, planetaries, diffused nebulosities, and the -“atmospheres” of “cloudy stars,” to be masses of “shining fluid.” As -for his “ambiguous objects,” they remain ambiguous still. “Clusters -in disguise” through enormous distance, give apparently the same -quality of light with irresolvable nebulæ. His inference that stars -and nebulæ form mixed systems has, moreover, been amply confirmed. No -one now denies their significant affinity, and very few their genetic -relationship. - -Herschel gave a list in 1811 of fifty-two dim, indefinite nebulosities, -covering in the aggregate 152 square degrees. “But this,” he added, -“gives us by no means the real limits” of the luminous appearance; -“while the depth corresponding to its superficial extent may be far -beyond the reach of our telescopes;” so “that the abundance of nebulous -matter diffused through such an expansion of the heavens must exceed -all imagination.” - -“The prophetic spirit of these remarks,” Professor Barnard comments, -“is being every day made more evident through the revelations of -photography.” He is himself one of the very few who have telescopically -verified any part of these suggestive observations. - -“I am familiar,” he wrote in _Knowledge_, January, 1892, “with a number -of regions in the heavens where vast diffusions of nebulous matter are -situated. One of these, in a singularly blank region, lies some five -or six degrees north-west of Antares, and covers many square degrees. -Another lies north of the Pleiades, between the cluster and the Milky -Way; a portion of this has recently been successfully photographed -by Dr. Archenhold. There is a large nebulous spot in that region, -easily visible to the naked eye, which I have seen for many years. When -sweeping there with a low power, the whole region between the Pleiades -and the Milky Way is perceived to be nebulous. These great areas of -nebulosity make their presence known by a singular dulling of the -ordinarily black sky, as if a thin veil of dust intervened.” They “are -specially suitable for the photographic plate, and it is only by such -means that they can be at all satisfactorily located.” - -Some of Herschel’s milky tracts have been thus pictured; notably one -in the Swan, shown on Dr. Max Wolf’s plates to involve the bright star -Gamma Cygni; and another immense formation extending over sixty square -degrees about the belt and sword of Orion, and joining on, Herschel was -“pretty sure,” to the great nebula. This, never unmistakably _seen_ -except by him, portrayed itself emphatically in 1886 in Professor E. -C. Pickering’s photographs. Herschel’s persuasion of the subordinate -character of the original “Fish-mouth nebula” was well-grounded. -On plates exposed by Professors W. H. Pickering and Barnard, it is -disclosed as the mere nucleus of a tremendous spiral, sweeping round -from Bellatrix to Rigel. - -Diffused nebulosities appear in photographs as far from homogeneous. -They are not simple volumes of gas indefinitely expanding in all -directions, after the manner of simple aeriform fluids. They possess, -on the contrary, characteristic shapes. Structureless nebulæ, like -structureless protoplasm, seem to be non-existent. In all, an -organising principle is at work. - -Minute telescopic stars showed to Herschel as prevalently red, owing, -he conjectured, to the enfeeblement of their blue rays during an -uncommonly long journey through space “not quite destitute of some very -subtle medium.” The argument is a remarkable one. It would be valid if -the ethereal vehicle of light exercised absorption after the manner of -ordinary attenuated substances. There is, however, reason to suppose -that the symptomatic redness was only a subjective impression, not an -objective fact. His colour-sense was not quite normal. The lower, to -his perception, somewhat overbalanced the higher end of the spectrum, -and his mirrors added to the inequality by reflecting a diminished -proportion of blue light. Thus he recorded many stars as tinged with -red which are now colourless, yet lie under no suspicion of change. - -Herschel was, in the highest and widest sense, the founder of sidereal -astronomy. He organised the science and set it going; he laid down -the principles of its future action; he accumulated materials for its -generalisations, and gave examples of how best to employ them. His work -was at once so stimulating and so practical that its abandonment might -be called impossible. Others were sure to resume where he had left -off. His son was his first and fittest successor; he was the only one -who undertook in its entirety the inherited task. Yet there are to be -found in every quarter of the world men imbued with William Herschel’s -sublime ambitions. Success swells the ranks of an invading army; and -the march of astronomy has, within the last decade, assumed a triumphal -character. The victory can never be completely won; the march can never -reach its final goal; but spoils are meanwhile gathered up by the -wayside which eager recruits are crowding in to share. The heavens -are, year by year, giving up secrets long and patiently watched for, -while holding in reserve many others still more mysterious. There is no -fear of interest being exhausted by disclosure. - -Herschel’s dim intuition that something might be learned about the -physical nature of the stars from the diverse quality of their light, -was verified after sixty-five years, by the early researches of -Secchi, Huggins, and Miller; but he could not suspect that, through -the chemical properties, which he guessed to belong in varying degrees -to the different sections of their spectra, pictures of the heavenly -bodies would be obtained more perfect than the telescopic views he -rapturously gazed at. Still less could he have imagined that, owing -to its faculty of accumulating impressions too weak to affect the -eye separately, the chemical would, in great measure, supersede the -telescopic method in carrying out the designs he had most at heart. - -Those designs have now grown to be of international importance. At -eighteen northern and southern observatories a photographic review -of the heavens is in progress. The combined results will be the -registration, in place and magnitude, of fifteen to twenty millions -of stars. The gauging of the skies will then be complete down to the -fourteenth magnitude; and the “construction of the heavens” can be -studied with materials of the best quality, and almost indefinite -in quantity. By simply “counting the gauges” on Herschel’s early -plan, much may be learnt; the amount of stellar condensation -towards the plane of the Milky Way, for instance, and the extent -of stellar denudation near its poles. A marked contrast between -the measures of distribution in these opposite directions will most -likely be brought into view. The application of his later method of -enumeration by magnitudes ought to prove even more instructive, but -may be very difficult. The obstacles, it is to be hoped, will not be -insurmountable; yet they look just now formidable enough. - -The grand problem with which Herschel grappled all his life involves -more complicated relations than he was aware of. It might be compared -to a fortress, the citadel of which can only be approached after -innumerable outworks have been stormed. That one man, urged on by -the exalted curiosity inspired by the contemplation of the heavens, -attempted to carry it by a _coup de main_, and, having made no -inconsiderable breach in its fortifications, withdrew from the -assault, his “banner torn, but flying,” must always be remembered with -amazement. - -[Illustration: CAROLINE LUCRETIA HERSCHEL. - -(_From a portrait taken by Tielemann in 1829._)] - - - - -CHAPTER VI. - -CAROLINE HERSCHEL. - - -Caroline Lucretia Herschel was born at Hanover, March 16th, 1750, and -was thus more than eleven years younger than the brother with whose -name hers is inseparably associated. She remembered the panic caused -by the earthquake of 1755, and her experience barely fell short of the -political earthquake of 1848; but the fundamental impressions of her -long life were connected with “minding the heavens.” - -She was of little account in her family, except as a menial. Her -father, indeed, a man of high character and cultivated mind, thought -much of her future, and wished to improve her prospects by giving her -some accomplishments. So he taught her to play the violin well enough -to take part in concerted music. But her instruction was practicable -only when her mother was out of the way, or in a particularly good -humour. Essentially a “Hausfrau,” Anna Ilse had no sympathy with -aspirations. She was hard-working and well-meaning, but narrow and -inflexible, and she kept her second daughter strictly to household -drudgery. Her literary education, accordingly, got no farther than -reading and writing; even the third “R” was denied to her. But she was -carefully trained in plain sewing and knitting, and supplied her four -brothers with stockings from so early an age that the first specimen of -her workmanship touched the ground while she stood upright finishing -the toe! Few signs of tenderness were accorded to her. Her eldest -brother, Jacob, a brilliant musician, and somewhat high-and-mighty -in his ways, did not spare cuffs when she waited awkwardly at table; -and her sister, Mrs. Griesbach, evidently took slight notice of her. -William, however, showed her invariable affection; and him and her -father she silently adored. In 1756, when they both returned from -England with the Hanoverian Guard, she recalled how, on the day of -their arrival, - -“My mother being very busy preparing dinner, had suffered me to go -all alone to the parade to meet my father, but I could not find him -anywhere, nor anybody whom I knew; so at last, when nearly frozen to -death, I came home and found them all at table. My dear brother William -threw down his knife and fork, and ran to welcome, and crouched down to -me, which made me forget all my grievances. The rest were so happy at -seeing one another again that my absence had never been perceived.” - -How well one can realise the disconsolate little expedition, the -woe-begone entry of the six-year-old maiden, her heart-chill on finding -herself forgotten, and the revulsion of joy at her soldier-brother’s -cordial greeting! - -Isaac Herschel died March 22nd, 1767. He had never recovered the -campaign of Dettingen, yet struggled, in spite of growing infirmities, -to earn a livelihood by giving lessons and copying music. His daughter -was thrown by his loss into a “state of stupefaction,” from which she -roused herself, after some weeks, to consider the gloomy outlook of -her destiny. She was seventeen, and was qualified, as she reflected -with anguish, only to be a housemaid. She was plain in face and -small in stature, and her father had often warned her that if she -ever married it would be comparatively late in life, when her fine -character had unfolded its attractions. Still, she did not lose hope -of making her way single-handed. Although over-burthened with servile -labours, she contrived, unknown to her mother, to get some teaching in -fancy-work from a consumptive girl whose cough from across the street -gave the signal for a daybreak rendezvous; trusting that, with this -acquirement, and “a little notion of music, she might obtain a place -as governess in some family where the want of a knowledge of French -would be no objection.” There was “no kind of ornamental needlework, -knotting, plaiting hair, stringing beads and bugles, of which she did -not make samples by way of mastering the art.” She was then permitted -to take some lessons in dressmaking and millinery. But the current of -her thoughts was completely changed by an invitation from her brother -William to join him at Bath. She was, if possible, to be made into -a concert-singer. Yet her voice had never been tried, and its very -existence was problematical. It may, then, be suspected that William’s -primary motive was to come to the rescue of his poor little Cinderella -sister. - -Months passed in “harassing uncertainty” as to whether she was to go or -stay; months, too, during which her own mind was divided between the -longing to follow her rising star, and a certain compunctious clinging -to her duties at home. Time, however, did not pass in idleness. -Taking no notice of the superior Jacob’s ridicule of her visionary -transformation into an artist, she quietly set about practising, with a -gag between her teeth, the solo parts of violin concertos, “shake and -all,” so that, as she says, “I had gained a tolerable execution before -I knew how to sing.” She occupied herself besides in making a store of -prospective clothing for relatives, who, she could not but fear, would -miss her services. For her withdrawal her mother, however, received -from William money-compensation, which enabled her to keep a servant -in lieu of her daughter. The parting, when he came to fetch her, in -August, 1772, was none the less a sorrowful one; but Caroline had much -to distract her mind from dwelling on those she had left behind. She -had, besides, much discomfort to endure. Six days and nights in an -open stage-carriage were followed by a tempestuous passage; the packet -in which they embarked at Helvoetsluys reached Yarmouth dismasted and -half-wrecked; and they were finally, not duly landed, but “thrown like -balls by two sailors,” on the English coast. After a brief glimpse of -London, they started, August 28th, in the night coach for Bath, where -Caroline arrived “almost annihilated” by fatigue and want of sleep. - -Her training for an unfamiliar life began without delay. She had to -learn English, arithmetic, and enough of account-keeping to qualify -her for conducting the household affairs; a routine of singing-lessons -and practising was entered upon; and she was sent out alone to market, -Alexander Herschel lurking behind to see that she came safely out of -the _mêlée_ of buyers and sellers, whence she brought home “whatever -in her fright she could pick up.” She suffered many things, too, from -her brother’s servant, “a hot-headed old Welshwoman,” whose _régime_ -was one of rack and ruin to domestic utensils; while _heimweh_ made -formidable onslaughts on her naturally serene spirits. - -A visit to London, as the guest of Mrs. Colebrook, one of her -brother’s pupils, gave her some experience of town gaieties. But the -expenses of dress and chairmen shocked her frugal ideas; and she -thought the young ladies, whose companionship was offered to her, “very -little better than idiots.” As a vocalist, Miss Herschel came easily -to the front. After a few months of study, her voice was in demand at -evening parties; when her foreign accentuation had been corrected, -she took the first soprano parts in “The Messiah,” “Samson,” “Judas -Maccabæus,” and other oratorios; and sang as prima donna at the winter -concerts both at Bath and Bristol. In accordance with her resolution -to appear only where her brother conducted, she declined an engagement -for a musical festival at Birmingham. A year’s training in deportment -was a preliminary to her _début_; a celebrated dancing mistress -being engaged--to use Caroline’s own phrase--“in drilling me for a -gentlewoman. Heaven knows how she succeeded!” A gift of ten guineas -from William provided her with a dress which made her, she was told, -“an ornament to the stage;” and she was complimented by the Marchioness -of Lothian on “pronouncing her words like an Englishwoman.” Her success -was decided, and promised to be enduring enough to satisfy her modest -ambition of supporting herself independently. - -It was, however, balked by an extraordinary turn of affairs; a turn -at first not at all to her liking. After the lapse of half-a-century -she still set it down as the grievance of her life that “I have been -throughout annoyed and hindered in my endeavours at perfecting myself -in any branch of knowledge by which I could hope to gain a creditable -livelihood.” - -William Herschel, when Caroline joined him at Bath, was just feeling -his way towards telescope-making. The fancy did not please her. The -beginnings of great things are usually a disturbance and an anxiety. -They imply a draft upon the future which may never be honoured, and -they often play sad havoc with the present. And Miss Herschel was -business-like and matter-of-fact. But her devotion triumphed over her -common-sense. Keeping her misgivings to herself, she met unlooked-for -demands with the utmost zeal, intelligence, and discretion. She was -always at hand when wanted, yet never in the way. Through her care, -some degree of domestic comfort was maintained amid the unwonted -confusion of optical manufacture. During the tedious process of -mirror-polishing, she sustained her brother physically and mentally, -putting food into his mouth, and reading aloud “Don Quixote,” and the -“Arabian Nights.” She was ready with direct aid, too, and “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.” “Alex,” she continued, “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, and sometimes whole papers which were lent him -for his perusal.” Musical business, meantime, received due attention. -Steady preparation was made for concerts and oratorios; choruses were -instructed, rehearsals attended, parts diligently written out from -scores. But the discovery of Uranus swept away the necessity for these -occupations; and with a final performance in St. Margaret’s Chapel, on -Whit-Sunday, 1782, the musical career of William and Caroline Herschel -came to a close. - -Miss Herschel’s “thoughts were anything but cheerful” on the occasion. -She saw the terrestrial ground cut from under her feet, and did not -yet appreciate the celestial situation held in reserve for her. Music, -in her opinion, was her true and only vocation; the contemplation -of herself in the guise of an assistant-astronomer moved her to -cynical self-scorn. As usual, however, her personal wishes were -suppressed. Housewifely cares, too, weighed upon her. The dilapidated -gazebo at Datchet provided no suitable shelter for a well-regulated -establishment. It was roofed more in appearance than in reality; the -plaster fell from the ceilings; the walls dripped with damp; rheumatism -and ague were its rightful inmates. Then the prices of provisions -appalled her, especially in view of the scarcity of five-pound notes -since the opulence of Bath had been exchanged for the penury of a court -precinct. - -Yet she set to work with a will to learn all that was needful for her -untried office. Not out of books. “My dear brother William,” she wrote -in 1831, “was my only teacher, and we began generally where we should -have ended; he supposing I knew all that went before.” The lessons were -of the most desultory kind. They consisted of answers to questions put -by her as occasions arose, during breakfast, or at odd moments. The -scraps of information thus snatched were carefully recorded in her -commonplace book, where they constituted a miscellaneous jumble of -elementary formulæ, solutions of problems in trigonometry, rules for -the use of tables of logarithms, for converting sidereal into solar -time, and the like. Nothing was entrusted to a memory compared by -her instructor to “sand, in which everything could be inscribed with -ease, but as easily effaced.” So that even the multiplication table was -carried about in her pocket. She appears never to have spent a single -hour in the systematic study of astronomy. Her method was that in vogue -at Dotheboys Hall, to “go and know it,” by practising, as it were, -blindfold, what she had been taught. Yet a computational error has -never, we believe, been imputed to her; and the volume of her work was -very great. - -Its progress was diversified by more exciting pursuits. She began, in -1782, to “sweep for comets,” and discovered with a 27-inch reflector, -in the autumn of 1783, two nebulæ of first-rate importance--one -a companion to the grand object in Andromeda, the other a superb -elliptical formation in Cetus. She was by this time more than -reconciled to her astronomical lot; Von Magellan, indeed, reported in -1785, that brother and sister were equally captivated with the stars. - -The original explorations, in which she was beginning to delight, were -interrupted by the commencement of his with the “large twenty-foot.” -Her aid was indispensable, and from December, 1783, she “became -entirely attached to the writing-desk.” She was no mere mechanical -assistant. A wound-up automaton would have ill served William -Herschel’s turn. He wanted “a being to execute his commands with the -quickness of lightning”; and his commands were various. For he was -making, not following precedents, and fresh exigencies continually -arose. Under these novel circumstances, his sister displayed incredible -zeal, promptitude, and versatility. She would throw down her pen to -run to the clock, to fetch and carry instruments, to measure the ground -between the lamp-micrometer and the observer’s eye; discharging these, -and many other successive tasks with a rapidity that kept pace with -his swift proceedings. Fatigue, want of sleep, cold, were disregarded; -and although nature often exacted next day penalties of weariness -and depression for those nights of intense activity, the faithful -amanuensis never complained. “I had the comfort,” she remarked simply, -“to see that my brother was satisfied with my endeavours to assist -him.” The service was not unaccompanied by danger. One night poor -Caroline, running in the dark over ground a foot deep in melting snow, -in order to make some alteration in the movement of the telescope, -fell over a great hook, which entered her leg so deeply that a couple -of ounces of her flesh remained behind when she was lifted off it. -The wound was formidable enough, in Dr. Lind’s opinion, to entitle a -soldier to six weeks’ hospital-nursing, but it was treated cursorily at -Datchet; the patient consoling herself for a few nights’ disablement -with the reflection that her brother, owing to cloudy weather, “was no -loser through the accident.” - -Busy days succeeded watchful nights. From the materials collected at -the telescope, she formed properly arranged catalogues, calculating, in -all, the places of 2,500 nebulæ. She brought the whole of Flamsteed’s -_British Catalogue_--then the _vade mecum_ of astronomers--into -zones of one degree wide, for the purpose of William’s methodical -examination; copied out his papers for the Royal Society; kept the -observing-books straight, and documents in order. Then, in the long -summer months, when “there was nothing but grinding and polishing to -be seen,” she took her share of that too, and “was indulged with the -last finishing of a very beautiful mirror for Sir William Watson.” - -On August 1st, 1786, her brother’s absence leaving her free to observe -on her own account, she discerned a round, hazy object, suspiciously -resembling a comet. Its motion within the next twenty-four hours -certified it as such, and she immediately announced the apparition to -her learned friends, Dr. Blagden and Mr. Aubert. The latter declared in -reply, “You have immortalised your name,” and saw in imagination “your -wonderfully clever and wonderfully amiable brother shedding,” upon -receipt of the intelligence, “a tear of joy.” This was the first of a -series of eight similar discoveries, in five of which her priority was -unquestioned. They were comprised within eleven years, and were made, -after 1790, with an excellent five-foot reflector mounted on the roof -of the house at Slough. Considering that she swept the heavens only as -an interlude to her regular duties, never for an hour forsaking her -place beside the great telescopes in the garden, her aptitude for that -fascinating pursuit must be rated very high. It was not until 1819 that -Encke identified her seventh comet--detected November 7th, 1795--with -one previously seen by Méchain in January, 1786. None other revolves -so quickly, its returns to perihelion occurring at intervals of three -and a quarter years. It has earned notoriety, besides, by a still -unexplained acceleration of movement. - -Caroline Herschel was the first woman to discover a comet; and her -remarkable success in what Miss Burney called “her eccentric vocation,” -procured for her an European reputation. But the homage which she -received did not disturb her sense of subordination. “Giving the sum of -more to that which hath too much,” she instinctively transferred her -meed of praise to her brother. She held her comets, notwithstanding, -very dear. All the documents relating to them were found after her -death neatly assorted in a packet labelled “Bills and Receipts of my -Comets”; and the telescopes with which they had been observed ranked -among the chief treasures of her old age. She presented the smaller one -before her death to her friend Mr. Hausmann; the five-foot to the Royal -Astronomical Society, where it is religiously preserved. - -The “celebrated comet-searcher” was described by Miss Burney in 1787 -as “very little, very gentle, very modest, and very ingenuous; and her -manners are those of a person unhackneyed and unawed by the world, -yet desirous to meet and return its smiles.” To Dr. Burney, ten years -later, she appeared “all shyness and virgin modesty”; while Mrs. -Papendick mentions her as “by no means prepossessing, but an excellent, -kind-hearted creature.” She was, in 1787, officially appointed her -brother’s assistant, with a salary of fifty pounds a year; “and in -October,” she relates, “I received twelve pounds ten, being the first -quarterly payment of my salary, and the first money I ever in all my -lifetime thought myself to be at liberty to spend to my own liking.” -The arrangement was made in anticipation of her brother’s marriage, -when--to quote her one bitter phrase on the subject--“she had to give -up the place of his housekeeper.” She did not readily accommodate -herself to the change; and a significant gap of ten years in her -journal suggests that she wrote much during that time of struggle -which her calmer judgment counselled her to destroy. Her strong sense -of right and habitual abnegation, however, came to her aid; the family -relations remained harmonious; and she eventually became deeply -attached to her gentle sister-in-law. But from 1788 onwards, she lived -in lodgings, either at Slough or Upton, whence she came regularly to -the observatory to do her daily or nightly work. - -Miss Herschel began in 1796, and finished in about twenty months, -an Index to Flamsteed’s observations of the stars in the “British -Catalogue.” A list of “errata” was added, together with a catalogue of -561 omitted stars. The work, one of eminent utility, was published in -1798, at the expense of the Royal Society. In August, 1799, she paid -a visit to the Astronomer Royal, with the object of transcribing into -his copy of Flamsteed’s Observations some memoranda upon them made by -her brother. “But the succession of amusements,” we hear, “left me no -alternative between contenting myself with one or two hours’ sleep per -night during the six days I was at Greenwich, and going home without -having fulfilled my purpose.” Needless to say that she chose the former. - -The Royal family paid her many attentions, partly, no doubt, because -of her intimacy with one of the ladies-in-waiting to the Queen. -This was Madame Beckedorff, who although of “gentle” condition, had -attended the same dressmaking class with the bandmaster’s daughter at -Hanover, in 1768. The distant acquaintanceship thus formed developed, -at Windsor, into a firm friendship, transmitted in its full cordiality -to a second generation. An entry in Caroline’s Diary tells of a dinner -at Madame Beckedorff’s, February 23, 1801, when the “whole party -left the dining-room on the Princesses Augusta and Amelia, and the -Duke of Cambridge coming in to see me.” In May, 1813, during a visit -to London, she passed several evenings at Buckingham House, “where I -just arrived,” she says, on May 12, “as the Queen and the Princesses -Elizabeth and Mary, and the Princess Sophia Matilda of Gloucester, -were ready to step into their chairs, going to Carlton House, full -dressed for a fête, and meeting me in the hall, they stopped for near -ten minutes, making each in their turn the kindest inquiries how I -liked London, etc. On entering Mrs. Beckedorff’s room, I found Madame -D’Arblay (Miss Burney), and we spent a very pleasant evening.” - -Such Royal condescensions were frequent, and on occasions inconvenient. -The Princesses Sophia and Amelia, in especial, took a strong liking -for Miss Herschel’s conversation, and often required her attendance -for many hours together. She was graciously singled out for notice at -the Frogmore assemblages, and became quite inured to the reception -at Slough of dignitaries and _savants_. Nothing deranged the simple -composure of her deportment. One would give much to know what were her -private impressions about the notabilities who crossed her path; but -her memoranda are, in this respect, perfectly colourless. Names and -dates are jotted down with the same brevity as her entries of “work -done.” Even the personal troubles of years are curtly disposed of. Her -brother Dietrich’s stay in England from 1809 to 1813, left her not a -day’s respite from accumulated trouble and anxiety. Yet it occasioned -only one little outburst, penned long afterwards. - -“He came,” she wrote, “ruined in health, spirit, and fortune, and, -according to the old Hanoverian custom, I was the only one from whom -all domestic comforts were expected. I hope I acquitted myself to -everybody’s satisfaction, for I never neglected my eldest brother’s -business” (Jacob Herschel died in 1792), “and the time I bestowed on -Dietrich was taken entirely from my sleep, or what is generally allowed -for meals, which were mostly taken running, or sometimes forgotten -entirely. But why think of it now?” - -Her later journal is overshadowed with the fear of coming bereavement. -Recurrences to the state of William’s health become ominously frequent. -“He is not only unwell, but low in spirits,” she notes in February, -1817; and the following account of his departure for Bath, April 2, -1818, betrays her deep trouble:-- - -“The last moments before he stepped into the carriage were spent in -walking 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.” - -“May 1st.--But he returned home much worse than he went, and for -several days hardly noticed my handiworks.” - -His last note to her, indited with an uncertain hand on a discoloured -slip of paper, July 4, 1819, she put by with the inscription: “I keep -this as a relic. Every line _now_ traced by the hand of my dear brother -becomes a treasure to me.” - -“Lina,” it ran, “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.” - -Through that long tail the earth had, eight days previously--according -to Olbers’s calculations--cut its way; but the proposed observations at -Slough, if made, were never published. - -In October, 1821, Caroline Herschel wrote this melancholy “Finis” to -what seemed to herself the only part of her life worth living. “Here -closed my day-book; for one day passed like another, except that I, -from my daily calls, returned to my solitary and cheerless home with -increased anxiety for each following day.” - -Eighteen months after her loss of “the dearest and best of brothers,” -she at last gathered fortitude to put on paper her recollections of the -“heartrending occurrences” witnessed by her during the closing months -of her fifty years’ sojourn in England. In every line of what she then -wrote, her absorbed fidelity to him, growing more and more tenacious -as the end drew visibly nigher, comes out with unconscious pathos. The -anguish with which she watched each symptom of decay seared her heart, -but was refused any outward expression. She played out her rôle of -self-suppression until the curtain fell. A last gleam of hope visited -her July 8th, 1822, when she marked down in an almanac the cheering -circumstance that her invalid had “walked 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,” she added sadly, “I never saw the like again.” - -In the impetuosity of her grief, she made an irreparable mistake. Only -a month earlier she had surrendered to her impecunious brother Dietrich -her little funded property of £500; now, without reflecting on the -consequences, she “gave herself, with all she was worth, to him and his -family.” She was in her seventy-third year; her only remaining business -in life, it seemed to her, was to quit it; the virtual close of her -career had come; the actual close could not long be delayed. So she -retired to her native place to die promptly, if that might be, but, at -any rate, to mark the chasm that separated her from the past. She soon -recognised, however, that she had taken a false step. “Why did I leave -happy England?” was the cry sometimes on her lips, always in her heart, -for a quarter of a century. She was taken aback by her own vitality. -She found out too late that her powers of work, far from being -exhausted, might have been turned to account for her nephew as they had -been for her brother. And it was to him and his mother, after all, that -her strong affections clung. Her relatives in Hanover, although they -treated her with consideration, were hopelessly uncongenial. “From the -moment I set foot on German ground,” she said, “I found I was alone.” -Fifty years is a huge gap in a human life. Miss Herschel had been all -that time progressing from the starting point where they had remained -stationary. Their tastes were then necessarily incongruous with hers; -nor could her interests be transplanted at will from the soil in which -they were rooted. She was unable to perceive that the change was in -herself. The “solitary and useless life” she led resulted, she was -convinced, from her “not finding Hanover, or anyone in it, like what I -left when the best of brothers took me with him to England in August, -1772!” - -An exile in her old home, she felt pledged to remain there. She would -not “take back her promise.” For a person of her frugal habits, she was -well off. Her pension of fifty pounds would have supplied her small -wants, and she was reluctantly compelled to accept the annuity of £100, -left to her by her brother. And since she was most generous in the -bestowal of her spare cash, her presence was of some material advantage -to a poor household. It gave them credit, too; and notwithstanding that -they “never could agree” in opinions, she faithfully nursed Dietrich -Herschel until his death in January, 1827. - -“I am still unsettled,” she wrote to her nephew, December 26th, 1822, -“and cannot get my books and papers in any order, for it is always noon -before I am well enough to do anything, and then visitors run away with -the rest of the day till the dinner-hour, which is two o’clock. Two or -three evenings in each week are spoiled by company. And at the heavens -there is no getting, for the high roofs of the opposite houses. But -within my room I am determined nothing shall be wanting that can please -my eye. Exactly facing me is a bookcase placed on a bureau, to which I -will have some glass doors made, so that I can see my books. Opposite -this, on a sofa, I am seated, with a sofa-table and my new writing-desk -before me; but what good I shall do there the future must tell.” - -Seated at that “new desk,” she completed her most important work. This -was the reduction into a catalogue, and the arrangement into zones, of -all Sir William Herschel’s nebulæ and clusters. Despatched to Sir John -Herschel in April, 1825, it made his review of those objects feasible. -From it, he drew up his “working-list” for each night’s observations; -and from it, in constructing his “General Catalogue” of 1864, he -took the places of such nebulæ as he had not been able to examine -personally. In the course of the needful comparisons, “I learned,” he -said, “fully to appreciate the skill, diligence, and accuracy which -that indefatigable lady brought to bear on a task which only the most -boundless devotion could have induced her to undertake, and enabled -her to accomplish.” For its execution, the Gold Medal of the Royal -Astronomical Society was awarded to her in 1828--an honour by which -she was “more shocked than gratified.” Her “Zone-Catalogue” was styled -by Sir David Brewster “an extraordinary monument of the unextinguished -ardour of a lady of seventy-five in the cause of abstract science.” - -In 1835, she was created an honorary member of the Royal Astronomical -Society, Mrs. Somerville being associated with her in a distinction -never before or since conferred upon a woman. Three years later, she -was surprised by the news that the Royal Irish Academy had similarly -enrolled her. “I cannot help,” she wrote, “crying out aloud to myself, -every now and then, What is that for?” The arrival, on another -occasion, of presentation-copies of Mrs. Somerville’s “Connexion of the -Physical Sciences,” and of Baily’s “Account of Flamsteed,” agitated her -painfully. “Coming to _me_ with such things,” she exclaimed, “an old, -poor, sick creature in her dotage.” “I think it is almost mocking me,” -she added in 1840, “to look upon me as a Member of an Academy; I that -have lived these eighteen years without finding as much as a single -comet.” - -Her local celebrity, nevertheless, diverted her. It struck her as a -capital joke that she was “stared at for a learned lady.” Down to 1840 -she regularly attended plays and concerts, and rarely left the theatre -without a “_Wie geht’s?_” from His Majesty. And to find herself--“a -_little_ old woman”--conspicuous in the crowd, produced a sense of -exhilaration. Her presence or absence was a matter of public concern, -and she very seldom appeared otherwise than alert and cheerful. When -close upon eighty her “nimbleness in walking,” she remarked, “has -hitherto gained me the admiration of all who know me; but the good -folks are not aware of the arts I make use of, which consist in never -leaving my room in the daytime except I am able to trip it along as -if nothing were the matter.” Music gave her unfailing pleasure. She -heard Catalani in 1828; shared in the Paganini _furore_ of 1831, and -conversed with him through an interpreter. With Ole Bull she was -“somewhat disappointed,” finding his performance “more like conjuration -than playing on a violin.” - -But her “painful solitude” was most of all cheered by the visits and -communications of eminent men. No one of distinction in science came -to Hanover without calling upon her. Humboldt, Gauss, Mädler, Encke, -Schumacher, paid her their respects, personally or by letter, if not in -both ways. “Next to listening to the conversation of learned men,” she -told the younger Lady Herschel, “I like to hear about them; but I find -myself, unfortunately, among beings who like nothing but smoking, big -talk on politics, wars, and such-like things.” Her situation remained, -to the end, displeasing to her. She made the best of it; but the best -was, to her thinking, bad. Having wilfully flung herself out of the -current of life, she was nevertheless surprised at being stranded. -She recurred, with inextinguishable pain, to the crippling effects of -circumstances and old age. - -“I lead a very idle life,” she wrote in 1826. “My sole employment -consists in keeping myself in good humour, and not being disagreeable -to others.” And in 1839: “I get up as usual, every day, change my -clothing, eat, drink, and go to sleep again on the sofa, except I am -roused by visitors; then I talk till I can talk no more--nineteen to -the dozen!” While at nights “the few, few stars I can get at out of my -window only cause me vexation, for to look for the small ones on the -globe my eyes will not serve me any longer.” - -She followed, however, with intense delight the progress of her -nephew’s career, in which she beheld the continuation of his father’s. -The intelligence of his having opened a nebular campaign in 1825, was -like the sound of the trumpet to a disabled war-horse. Nothing but -the decline of her powers, she assured him, would have prevented her -“coming by the first steamboat to offer you the same assistance as, by -your father’s instructions, I was enabled to afford him.” And again, -in 1831: “You have made me completely happy with the account you sent -me of the double stars; but it vexes me more and more that in this -abominable city there is no one who is capable of partaking in the -joy I feel on this revival of your father’s name. His observations on -double stars were, from first to last, the most interesting subject; he -never lost sight of it. And I cannot help lamenting that he could not -take to his grave the satisfaction I feel at seeing his son doing him -such ample justice by endeavouring to perfect what he could only begin.” - -Sir John’s trip to the Cape roused her ardent sympathy. “Ja!” she -exclaimed, on hearing of the project, “If I were thirty or forty years -younger, and could go too. In Gottes Namen!” But she was eighty-two, -and could only give vent to her feelings by “jingling glasses -with Betty” after dinner on his birthday, while mistress and maid -together cried, “Es lebe Sir John! Hoch! Hurrah!” The reports of his -achievements in the southern hemisphere were, she said, “like a drop -of oil supplying my expiring lamp.” “At first, on reading them,” she -wrote to Lady Herschel, “I could turn wild; but this is only a flash; -for soon I fall into a reverie on what my dear nephew’s father would -have felt if such letters could have been directed to him, and cannot -suppress my wish that _his_ life instead of _mine_ had been spared -until this present moment.” - -The joyful intelligence of her nephew’s safe return to England was -sent to Miss Herschel by the Duke of Cambridge, whose attentions to -her were unfailing; and she lived to hold in her hands the volume of -“Cape Results,” by which her brother’s great survey of the heavens -was rounded off to completion. But by that time the lassitude of -approaching death was upon her. - -Three visits from her nephew broke the monotony of separation. In -October, 1824, he stopped at Hanover on his way homeward from the -Continent. Before his arrival, her “arms were longing to receive him”; -after his departure, she “followed him in idea every inch he moved -farther” away from her. Six years passed, and then he came again. - -“I found my aunt,” he reported, June 19th, 1832, “wonderfully well, and -very nicely and comfortably lodged, and we have since been on the full -trot. She runs about the town with me, and skips up her two flights of -stairs as light and fresh at least as some folks I could name who are -not a fourth part of her age. In the morning till eleven or twelve she -is dull and weary; but as the day advances she gains life, and is quite -‘fresh and funny’ at ten or eleven p.m., and sings old rhymes, nay, -even dances! to the great delight of all who see her.” - -Their final meeting was in 1838, when Sir John’s Cape laurels were just -gathered; and he brought with him his eldest son, aged six. But the -old lady was terrified lest the child should come to harm; his food, -his sleep, his scramblings, his playthings, were all subjects of the -deepest anxiety. Then Sir John, desiring to spare her “the sadness of -farewell,” perpetrated a moonlight flitting, which left her dismayed -and desolate at the abrupt termination of the visit, and smarting -with the intolerable consciousness of opportunities lost for saying -what could now never be said. “All that passed,” she said, “was like -Sheridan’s Chapter of Accidents.” It was too much for her; she did not -desire the repetition of a pleasure rated at a price higher than she -could afford to pay. “I would not wish on any account,” she told Lady -Herschel in 1842, “to see either my nephew or you, my dear niece, again -in this world, for I could not endure the pain of parting once more; -but I trust I shall find and know you in the next.” - -She lived habitually in the past, and found the present--as Mrs. -Knipping, Dietrich’s daughter said--“not only strange, but annoying.” -Sometimes she would rouse herself from a “melancholy lethargy” to spend -a few moments “in looking over my store of astronomical and other -memorandums of upwards of fifty years’ collecting, and destroying -all that might produce nonsense when coming through the hands of a -Block-kopf into the Zeitungen.” Again she would dip back into the -career of the “forty-foot,” or recall the choral performance to -which the tube had resounded not far from sixty years before, “when -I was one of the nimblest and foremost to get in and out of it. But -now--lack-a-day--I can hardly cross the room without help. But what of -that? Dorcas, in the _Beggars’ Opera_, says: - - “‘One cannot eat one’s cake and have it too!’” - -That venerable instrument marked for her the _ne plus ultra_ of optical -achievement. She would not admit the sacrilegious thought of its being -outdone. “I believe I have water on my brains,” she informed her nephew -in August, 1842, “and all my bones ache so that I can hardly crawl; -and, besides, sometimes a whole week passes without anybody coming -near me, till they stumble on a paragraph in the newspaper about -Gruithuisen’s discoveries, or Lord Queenstown’s great telescope, which -_shall_ beat Sir William Herschel’s all to nothing; and such a visit -sometimes makes me merry for a whole day.” - -From time to time she wrote books of “Recollections,” which she -forwarded, with anxious care, to England. They contain nearly all that -is intimately known of Sir William Herschel’s life. The entries in her -“Day-book” ceased finally only on September 3rd, 1845. In the hope of -giving permanent form to the memories that haunted her, she began, at -ninety-two, “a piece of work which I despair of finishing before my -eyesight and life leave me in the lurch. You will, perhaps, wonder what -such a thing can be as I may pretend to do; but I cannot help it, and -shall not rest till I have wrote the history of the Herschels.” “You -remember,” she added, “you take the work in whatever state I may leave -it, and make the best of it at your leisure.” It remained a piquant -fragment. The fervour of her start was soon quenched by physical -collapse, and she acknowledged her powerlessness “to do anything beside -keeping herself alive.” Her last letter to Collingwood was finished -with difficulty, December 3rd, 1846. Monthly reports of her state, -however, continued to be sent thither by Miss Beckedorff, who, with -Mrs. Knipping, cared for her to the last. - -In honour of her ninety-sixth birthday, the King of Prussia sent her, -through Humboldt’s friendly hands, the Gold Medal of Science; and on -the following anniversary, March 16th, 1847, she entertained the Crown -Prince and Princess for two hours. Not only with conversation; she -sang to them, too, a composition of Sir William’s, “Suppose we sing a -Catch.” She had a new gown and smart cap for the occasion; and seemed -“more revived than exhausted” by her efforts. Her last message to her -nephew and his family--sent March 31st--was to say, with her “best -love” “that she often wished to be with them, often felt alone, did not -quite like old age with its weaknesses and infirmities, but that she, -too, sometimes laughed at the world, liked her meals, and was satisfied -with Betty’s services.” - -On the 9th of January, 1848, she tranquilly breathed her last, and “the -unquiet heart was at rest.” She was buried beside her parents in the -churchyard of the Gartengemeinde, at Hanover, with an epitaph of her -own composition.[F] It records that the eyes closed in death had in -life been turned towards the “starry heavens,” as her discoveries of -comets, and her participation in her brother’s “immortal labours,” bear -witness to future ages. By her special request a lock of “her revered -brother’s” hair, and an old almanac used by her father, were placed in -her coffin, which was escorted to the grave by royal carriages, and -covered with wreaths of laurel and cypress from the royal gardens at -Herrenhausen. - - [F] “Der Blick der Verklärten war hienieden dem gestirnten - Himmel zugewandt; die eigenen Cometen-Entdeckungen, - und die Theilnahme an den unsterblichen Arbeiten ihres - Bruders, Wilhelm Herschel, zeugen davon bis in die späteste - Nachwelt.” - -Caroline Herschel was not a woman of genius. Her mind was sound and -vigorous, rather than brilliant. No abstract enthusiasm inspired her; -no line of inquiry attracted her; she seems to have remained ignorant -even of the subsequent history of her own comets. She prized them as -trophies, but not unduly. The assignment of property in comets reminded -her, she humorously remarked, when in her ninety-third year, of the -children’s game, “He who first cries ‘Kick!’ shall have the apple.” -Yet her faculties were of no common order, and they were rendered -serviceable by moral strength and absolute devotedness. Her persistence -was indomitable, her zeal was tempered by good sense; her endurance, -courage, docility, and self-forgetfulness went to the limits of what -is possible to human nature. With her readiness of hand and eye, her -precision, her rapidity, her prompt obedience to a word or glance, she -realised the ideal of what an assistant should be. - -Herself and her performances she held in small esteem. Compliments and -honours had no inflating effect upon her. Indeed, she deprecated them, -lest they should tend to diminish her brother’s glory. “Saying too -much of what I have done,” she wrote in 1826, “is saying too little -of him, for he did all. I was a mere tool which _he_ had the trouble -of sharpening and adapting for the purpose he wanted it, for lack of -a better. A little praise is very comforting, and I feel confident -of having deserved it for my patience and perseverance, but none for -great abilities or knowledge.” Again: “I did nothing for my brother but -what a well-trained puppy-dog would have done; that is to say, I did -what he commanded me.” And her entire and touching humility appears -concentrated in the following sentence from a letter to her nephew: “My -only reason for saying so much of myself is to show with what miserable -assistance your father made shift to obtain the means of exploring the -heavens.” - -The aim in life of this admirable woman was not to become learned -or famous, but to make herself useful. Her function was, in her own -unvarying opinion, a strictly secondary one. She had no ambition. -Distinctions came to her unsought and incidentally. She was accordingly -content with the slight and fragmentary supply of knowledge sufficing -for the accurate performance of her daily tasks. No inner craving -tormented her into amplifying it. The following of any such impulse -would probably have impaired, rather than improved, her efficiency. -The turn of her mind was, above all things, practical. She used -formulæ as other women use pins, needles and scissors, for certain -definite purposes, but with complete indifference as to the mode of -their manufacture. What was required of her, however, she accomplished -superlatively well, and this was the summit of her desires. She shines, -and will continue to shine, by the reflected light that she loved. - - - - -CHAPTER VII. - -SIR JOHN HERSCHEL AT CAMBRIDGE AND SLOUGH. - - -“The little boy is entertaining, comical, and promising,” Dr. Burney -wrote after his visit to Slough in 1797. John Frederick William -Herschel was then five years old, having been born “within the shadow -of the great telescope” March 7, 1792. He was an industrious little -fellow, especially in doing mischief. “When one day I was sitting -beside him,” his aunt relates, “listening to his prattle, my attention -was drawn by his hammering to see what he might be about, and I found -that it was the continuation of many days’ labour, and that the ground -about the corner of the house was undermined, the corner-stone entirely -away, and he was hard at work going on with the next. I gave the alarm, -and old John Wiltshire, a favourite carpenter, came running, crying -out, ‘God bless the boy, if he is not going to pull the house down!’” -And she wrote to him at Feldhausen; “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 crying out, ‘Dang the boy, if he -can’t drive in a nail as well as I can!’” - -[Illustration: SIR JOHN FREDERICK WILLIAM HERSCHEL, BART. - -(_From a portrait painted by Pickersgill for St. John’s College, -Cambridge._)] - -“John and I,” she told his wife, “were the most affectionate friends, -and many a half or whole holiday spent with me was dedicated to making -experiments in chemistry, in which generally all boxes, tops of -tea-canisters, pepper-boxes, teacups, etc., served for the necessary -vessels, and the sand-tub furnished the matter to be analysed. I only -had to take care to exclude water, which would have produced havoc on -my carpet.” - -From a preparatory school kept by Dr. Gretton at Hitcham, he was sent, -a delicate, blue-eyed lad, to Eton. His mother, however, happening to -see him maltreated by a stronger boy, brought him home after a few -months, and his education was continued by a Scotch mathematician named -Rogers, a man of considerable ability. His pupil held him in high -respect; yet, though he learned Euclid accurately from him, he told -Dr. Pritchard afterwards that “he knew no more of its real bearing and -intention than he knew of the man in the moon.” The results of the home -tuition were, none the less, exceedingly brilliant. - -Herschel entered St. John’s College, Cambridge, at the age of -seventeen, and his aunt noted in her Diary that, from the time of his -admittance to the University until he quitted it, he gained all the -first prizes without exception. He graduated as Senior Wrangler and -First Smith’s Prizeman in 1813, a year in which honours were not cheap. -Peacock, subsequently Dean of Ely, took second place, Fearon Fallows, -the first Royal Astronomer at the Cape of Good Hope, came third, and -Babbage withdrew from the competition, judging himself unable to beat, -and not caring to be beaten by Herschel. Rivalry did not disturb their -friendship. Having entered, together with Peacock, into a juvenile -compact to do what in them lay “to leave the world wiser than they -found it,” they, in 1812, set about fulfilling it by the establishment -of the “Analytical Society of Cambridge.” Its object was to substitute -in England for Newton’s fluxional method the more flexible and powerful -calculus in use on the Continent; or, as Babbage expressed it, punning -on the required change of notation, “to uphold the principles of pure -D-ism in opposition to the _Dot_-age of the University.” The trio of -innovators were full of enthusiasm, and they carried through a reform -vital to the progress of British science. Herschel laboured zealously -in the cause. In combination with his two allies, he translated -Lacroix’s elementary treatise on the Differential Calculus, which -became a text-book at Cambridge; and published, in 1820, an admirable -volume of “Examples.” “In a very few years,” to use Babbage’s words, -“the change from dots to d’s was accomplished; and thus at last the -English cultivators of mathematical science, untrammelled by a limited -and imperfect system of signs, entered on equal terms into competition -with their Continental rivals.” Herschel, writing in the _Quarterly -Review_, playfully described the process by which this was brought -about. “The brows of many a Cambridge moderator,” he said, “were -elevated, half in ire, half in admiration, at the unusual answers which -began to appear in examination-papers. Even moderators are not made -of impenetrable stuff; their souls were touched, though fenced with -seven-fold Jacquier, and tough bull-hide of Vince and Wood. They were -carried away with the stream, in short, or replaced by successors full -of their newly acquired powers. The modern analysis was adopted in its -largest extent.” - -John Herschel was one of Babbage’s “chief and choicest companions,” who -breakfasted with him every Sunday after chapel, and discussed, during -three or four delightful hours, “all knowable, and many unknowable -things.” His life-long friendship with Whewell began after his election -to a Fellowship of his College. It lent charm to the occasional -residences at Cambridge, which terminated in 1816, on his attaining the -dignity of Master of Arts. He celebrated his coming of age at home, -and was with his father at Brighton when Campbell characterised him as -“a prodigy in science, and fond of poetry, but very unassuming.” His -first publication was a paper on “Cotes’s Theorem,” sent, in October, -1812, to the Royal Society, of which body he was chosen a member, May -27, 1813. This was followed by a series of memoirs on various points -of analysis, their signal merit being recognised, in 1821, by the -bestowal of the Copley Medal. His investigations in pure mathematics -were carried no further; but he had done enough to show his power and -originality, and materially to widen the scope of the new methods. - -He was in no hurry to choose a profession. Evenly balanced inclinations -demanded, circumstances indulged delay; so he paused. His father wished -him to enter the Church; but he preferred the law, and was enrolled -a student at Lincoln’s Inn, January 24, 1814. The step was a simple -formality. It committed him to nothing. And, in fact, while nominally -reading for the Bar, his thoughts were running in a totally different -direction. Dr. Wollaston, whose acquaintance he made in London, -fascinated him, and his influence served to steady the helm of his -intentions. Having decided finally for a scientific career, he returned -to Slough, and plunged into experiments in chemistry and physical -optics. - -On September 10th, 1816, he informed a correspondent that he was -“going, under his father’s direction, to take up star-gazing.” This -brief sentence gives the first tidings of an astronomical element in -his life. Its growth was slow. He had no instinctive turn that way. It -was through filial reverence that he resolved to tread in his father’s -footsteps. His self-denial received a magnificent reward. He took a -place expressly reserved for him, as it might seem, beside his father -as an explorer of the skies on the grandest scale. But for this moral -purpose, he might have squandered time in a multiplicity of partial -researches. So late as 1830 he told Sir William Rowan Hamilton: “I find -it impossible to dwell for very long on one subject, and this renders -my pursuit of any branch of science necessarily very desultory.” His -nebulæ and double stars saved him from being “everything by turns, -and nothing long.” Their collection and revisal, begun as a duty, -grew to be irresistibly attractive, and John Herschel pledged himself -definitively to astronomy. - -His earliest undertaking was the re-examination of his father’s -double stars. Entered upon at Slough in 1816, it was continued from -1821 to 1823 at the observatory in Blackman Street, Southwark, of -Mr., afterwards Sir James South, where, with two excellent refracting -telescopes, of five and seven feet focal length, the colleagues -measured 380 of Sir William Herschel’s original pairs. Double stars -want a great deal of looking after. Their discovery should be the -prelude to long processes of investigation. It is of little interest -unless diligently followed up. Each represents a system, individual -in its peculiarities, and probably of most complex organisation. -The more such systems are studied, the more wonderful they appear. -Two associated stars have often proved, on keener scrutiny, to be -themselves very closely double; and in other cases, disturbed motion -has revealed the existence of obscure masses--planets on a colossal -scale, possibly the spacious abodes of unimaginable forms of life. - -The “Astronomy of the Invisible,” however, was still in the future when -Herschel and South did their work. Facts relating to binary revolutions -were scantily forthcoming, and the science to be founded on them had -been rather indicated than established. Fresh observations were then -needed to ascertain how the circling stars had behaved since 1802. The -results proved highly satisfactory. In Francis Baily’s words, “The -remarkable phenomena first brought to light by Sir William Herschel -were abundantly confirmed, and many new objects pointed out as worthy -the attention of future observers.” To take a couple of examples. Eta -Coronæ was found to have described, since 1781, one entire round, -and to be just starting on a second. Again, Tau Ophiuchi had been -perceived, by the elder Herschel, at his first sight of it in April, -1783, to be “elongated.” “One half of the small star,” he said, “if -not three-quarters, seems to be behind the large star.” This effect -was imperceptible to his son. It had become entirely effaced in the -course of forty years. The star was, in 1823, perfectly round; it had, -as it were, absorbed its companion. By slow degrees, however, the two -came into separate view, and now form an easy telescopic object. Their -period of revolution is not less than two centuries. Another point of -special interest was the detection of marked eccentricity in a stellar -orbit--that of Xi Ursæ Majoris. These stars perform their circuits in -just sixty years; but in 1821 their apparent speed was so great that -changes in their relative positions could be determined from month to -month. For these observations, published with notes and discussions in -the _Philosophical Transactions_ for 1824, Herschel and South received -the Lalande Prize of the French Academy in 1825, and the Gold Medal of -the Astronomical Society in 1826. In the latter distinction, Wilhelm -Struve and Amici of Modena were associated with them. These four were -the only double star observers then living. - -Their exertions served to define more closely the circumstances of -stellar movement. The crucial question could now be put, whether they -are governed by the force that binds the planets to the sun, or by -some other form of attractive influence. In other words, is the law of -gravitation universal? An answer could only be obtained experimentally, -by computing, on gravitational principles, the paths of the best-known -pairs, and then _trying the fit_. If the stars, as time went on, kept -near their predicted places, the unity of nature in this respect might -be safely inferred; although considerable discrepancies might in any -case be expected, owing to errors of measurement minute in themselves, -but large relatively to curves reduced by distance to hair-breadth -dimensions. - -This kind of inquiry was fairly started in 1827, when Savary computed -the orbit of Xi Ursæ. His success made it almost certain that the pair -moved under the planetary regimen, conformed to, there is no reason -to doubt, by all binaries. John Herschel, although not the first, was -the most effective early investigator of stellar orbits. His method, -described before the Royal Astronomical Society January 13, 1832, and -approved by the award of its Gold Medal in 1833, went to the root of -the matter. The author declared it a mere waste of time to attempt to -deal, by any refined or intricate process of calculation, with data so -uncertain and irregular as those at hand. “Uncertain and irregular,” -it must be repeated, because referred to a scale on which tenths of -a second assume large proportions. He accordingly discarded, as mere -pedantic trifling, such analytical formulæ as those employed by Savary -and Encke, and had recourse to a graphical process, in which “the -aid of the eye and hand” was used to “guide the judgment in a case -where judgment only, and not calculation, could be of any avail.” The -operation which he went on to explain was commended by Sir George Airy -for its “elegance and practical utility.” Nothing more appropriate -could have been devised than this plan, at once simple, ingenious, and -accommodating, for drawing a curve representative of the successive -relative positions of double stars. Its invention effectively promoted -acquaintance with their orbits; most of those at present known having, -indeed, been calculated with its aid. - -In 1821, Herschel travelled, in Babbage’s company, through Switzerland -and Italy. His only recorded adventure was an ascent of Monte Rosa. -In the following year he visited Holland with James Grahame, the -learned author of a “History of America”; and on the removal of -South’s observatory to Passy, he again went abroad, starting with -Babbage, but returning alone. This time he made a number of scientific -acquaintances. His father’s name worked like a spell. “I find myself,” -he said, “for his sake, received by all men of science with open arms.” -His modesty forbade him to remember that his own merits were already -conspicuous. In Paris, Arago and Fourier showed him all possible -attentions; he was welcomed at Turin “like a brother” by Plana, “one -of the most eminent mathematicians of the age;” at Modena, Amici was, -if possible, still more cordial. “He is the only man,” Herschel told -his aunt, “who has, since my father, bestowed great pains on the -construction of specula.” “Among other of your inquiring friends,” he -continued, “I should not omit the Abbé Piazzi, whom I found ill in -bed at Palermo, and who is a fine, respectable old man, though, I am -afraid, not much longer for this world. He remembered you personally, -having himself visited Slough.” - -On July 3 Herschel “made the ascent of Etna, without particular -difficulty, though with excessive fatigue.” On the summit, reached -before sunrise, by “a desperate scramble up a cone of lava and ashes, -one thousand feet high,” he found himself “enveloped in suffocating -sulphurous vapours”; and “was glad enough to get down,” after having -made a reading of the barometer in concert with the simultaneous -observations of the brothers Gemellaro at Catania and Nicolosi. The -same night he arrived at Catania “almost dead” from the morning’s -arduous climb, “and the dreadful descent of nearly thirty miles, where -the mules could scarce keep their feet.” - -In traversing Germany, he deviated to Erlangen, where Pfaff was -engaged in translating Sir William Herschel’s writings; and visited -Encke, Lindenau, and Harding, at Seeberg, Gotha, and Göttingen. With -Göttingen he had a special tie through his creation, in 1816, an -honorary member of the University; and at Göttingen, too, he hoped to -meet Gauss--a man of strange, and--to the lay mind--unintelligible -powers. “Gauss was a god,” one of his fellow-mathematicians said of -him; but the “god” was on this occasion absent--feasting with the -“blameless Ethiopians,” perhaps, like the Homeric deities when wanted. -He was reported “inconsolable” for the lost opportunity, which seems -never to have recurred. - -From Munich Herschel wrote to his aunt, in view of his approaching -visit to Hanover:--“I hope you haven’t forgotten your English, as -I find myself not quite so fluent in this language (German) as I -expected. In fact, since leaving Italy, I have so begarbled my German -with Italian that it is unintelligible both to myself and to everyone -that hears it: and what is very perverse, though when in Italy I could -hardly talk Italian fit to be heard, I can now talk nothing else, and -whenever I want a German word, pop comes the Italian one in its place. -I made the waiter to-day stare (he being a Frenchman) by calling to -him, ‘Wollen Sie avere la bontà den acet zu apportaren!’ But this, I -hope, will soon wear off.” - -His next foreign holiday was spent in France. He had designed a new -instrument for measuring the intensity of the sun’s radiations, and -was eager to experiment with it alternately at high and low levels, -for the purpose of determining the proportion of solar heat absorbed -by the earth’s atmosphere. This method was employed with fine effect -by Professor Langley on Mount Whitney in 1881. Herschel carried his -“actinometer” to the top of the Puy de Dôme in September 1826, and -waited at Montpellier for “one day of intense sunshine,” in order -to procure his second term of comparison. The Puy de Dôme, with its -associated three hundred summits, strongly allured him. “I have been -rambling over the volcanoes of Auvergne,” he wrote from Montpellier, -September 17, “and propose, before I quit this, to visit an extinct -crater which has given off two streams of lava at Agde, a town about -thirty miles south of this place on the road to the Spanish frontier. -Into Spain, however, I do not mean to go--having no wish to have my -throat cut. I am told that a regular diligence runs between this and -Madrid, and is as regularly stopped and robbed on the way.” - -This exploratory turn alarmed Miss Herschel. “I fear,” she replied, -“you must often be exposed to great dangers by creeping about in holes -and corners among craters of volcanoes.” He was, nevertheless, only -dissuaded by his mother’s anxious remonstrances from pursuing their -study in Madeira and Teneriffe. - -In the autumn of 1827, Babbage accompanied him to Ireland. The young -Astronomer Royal, Sir W. R. Hamilton, was unluckily absent at the time -of their visit; but he sent Herschel, by way of compensation, one of -his brilliant optical essays, and a correspondence sprang up from which -a lasting friendship developed. - -Herschel’s scientific occupations at home were meanwhile various and -pressing. He co-operated in the foundation of the Astronomical Society, -and became in 1821 its first foreign secretary. In 1824 he undertook -the more onerous duties of secretary to the Royal Society, and rented a -house in Devonshire Street for the three years of his term of office. -Astronomy, it might have been feared, should be at least temporarily -shelved; yet he informed his aunt, April 18, 1825, “A week ago I had -the twenty-foot directed on the nebulæ in Virgo, and determined the -right ascensions and polar distances of thirty-six of them. These -curious objects I shall now take into my especial charge--nobody else -can see them.” - -His telescope, in fact, then held the championship. It was constructed -in 1820 by himself, under his father’s directions, on the “front view” -plan, the speculum being eighteen inches in diameter, and of twenty -feet focal length. With it he executed, in 1824, a fine drawing of the -Orion Nebula, with which “inexplicable phenomenon” he was profoundly -impressed. It suggested to him no idea of a starry composition, and he -likened its aspect to that presented by the “breaking up of a mackerel -sky, when the clouds of which it consists begin to assume a cirrous -appearance.” - -In July, 1828, he succeeded in discerning the two Uranian satellites, -Oberon and Titania, _authentically_ discovered by his father. They had -not been seen, except incidentally at Slough, for thirty years. His -pursuit of them, continued at intervals until 1832, had the result -of confirming, while slightly correcting, Sir William Herschel’s -elements of their motions. On September 23, 1832, he perceived Biela’s -comet as a round, hazy object without a tail. It closely simulated a -pretty large nebula. A small knot of very faint stars lay directly -in its path, and, having before long overtaken them, it “presented, -when on the cluster, the appearance of a nebula partly resolved into -stars, the stars of the cluster being visible through the comet.” They -shone undimmed, he estimated, from behind a veil of cometary matter -50,000 miles thick. Yet, only a month later, the remote prospect of a -collision with this tenuous body threw Europe into a panic. - -After Sir William Herschel’s death, his son formed the project of -collecting into a memorial volume all his published papers; but he -decided before long that he could add more to his fame by pursuing -and verifying his observations than by reprinting them. The keynote -of his life’s activity was struck in these words. His review of the -2,500 Herschelian nebulæ, more than half of which were invisible with -any instrument except his own, was begun in the summer of 1825, and -terminated in 1833. The assiduity with which it was prosecuted appeared -by its completion in little more than half the time judged necessary -for the purpose by the original discoverer. Yet he was not exempt -from discouragement. “Two stars last night,” he wrote, July 23, 1830, -“and sat up till two waiting for them. Ditto the night before. Sick -of star-gazing--mean to break the telescopes and melt the mirrors.” -Very few glimpses of this seamy side to the occupation are afforded us -by either of the Slough observers. Modern astronomers, by comparison, -would seem, like the Scotchman’s barometer, to have “lost all control -over the weather.” - -The efficacious promptitude with which John Herschel swept the skies -appears truly wonderful when we remember that he was without a skilled -assistant. No ready pen was at hand to record what he saw, and how -he saw it; he was, by necessity, his own amanuensis; and writing by -lamplight unfits the eye for receiving delicate impressions. Yet a -multitude of the objects for which quest was being made were of the -last degree of faintness. The results were none the less admirable. -Embodied in a catalogue of 2,307 nebulæ, of which 525 were new, they -were presented to the Royal Society July 1, 1833, and printed in the -_Philosophical Transactions_ (vol. cxxiii.). Annotations of great -interest, and over one hundred beautiful drawings, enhanced the value -of the memoir. - -Herschel was struck, in the course of his review, by the nebulous -relations of double stars. A close, faint pair at the exact centre of -a small round nebula in Leo; stellar foci in nebular ellipses; and a -strange little group consisting of a trio of equidistant stars relieved -against a nebulous shield, were specimen-instances illustrating “a -point of curious and high physical interest.” - -He also drew attention to “the frequent and close proximity to -planetary nebulæ of minute stars which suggest the idea of accompanying -satellites. Such they may possibly be.” If so, their revolutions might -eventually be ascertained; and he urged the desirability of exact and -persistent determinations of the positions of these satellite-stars. -“I regret,” he concluded, “not having sufficiently attended to this in -my observations, the few measures given being hurried, imperfect, and -discordant.” Up to the present, these supposed systems have remained -sensibly fixed; but they have been a good deal neglected. Mr. Burnham’s -observations, however, with the Lick refractor in 1890–1, may supply a -basis for the future detection of their movements in periods probably -to be reckoned by millenniums. - -The orbital circulation of compound nebulæ must be at least equally -slow. They are most diverse in form and arrangement. “All the varieties -of double stars as to distance, position, and relative brightness,” -Herschel wrote, “have their counterparts in nebulæ; besides which, the -varieties of form and gradation of light in the latter afford room for -combinations peculiar to this class of objects.” Such, for instance, as -the disparate union of an immensely long nebulous ray in Canes Venatici -with a dim round companion, a small intermediate star occupying -possibly the centre of gravity of the system. - -Herschel’s drawings of double nebulæ have gained significance through -their discussion, in 1892, by Dr. T. J. J. See of Chicago. They are -now perceived to form a series aptly illustrative of the process, -theoretically investigated by Poincaré and Darwin, by which a cooling -and contracting body, under the stress of its consequently accelerated -rotation, divides into two. If it be homogeneous in composition, -its “fission” gives rise to two equal masses, presumed to condense -eventually into a pair of equal stars. Disparity, on the other hand, -between the products of fission indicates original heterogeneity; -so that a large nebula must be of denser consistence than a smaller -one physically connected with it. The chemical dissimilarity of the -stars developed from them might explain the colour-contrasts often -presented by unequal stellar couples. This view as to the origin of -double nebulæ, and through them of double stars, although doubtless -representing only a fragment of the truth, gives wonderful coherence to -Herschel’s faithful delineations of what his telescope showed him. - -No one before him had completely seen the “Dumb-bell” nebula in -Vulpecula. Sir William Herschel had perceived the “double-headed shot” -part of this “most amazing object,” but had missed the hazy sheath -which his successor noticed as filling in the elliptic outline. He -perceived similarly (unaware of Schröter’s observation) that the -interior of the Ring-nebula in Lyra is not entirely dark; and compared -the effect to that of fine gauze stretched over a hoop. An exceedingly -long, nebular ellipse in Andromeda, with a narrow interior vacuity, -left him “hardly a doubt of its being a thin, flat ring of enormous -dimensions, seen very obliquely.” A photograph taken by Dr. Roberts, in -1891, corresponds strikingly with Herschel’s drawing. Some specimens of -“rifted nebulæ,” were also included in the collection of 1833. They are -double or even triple parallel rays, fragments, apparently, of single -primitive formations. Herschel might well assert that “some of the most -remarkable peculiarities of nebulæ had escaped every former observer.” - -Both by the Royal, and by the Royal Astronomical Societies, medals -were, in 1836, adjudged to this fine work. Its progress was -accompanied by the discovery of 3,347 double stars, as well as by the -re-measurement of a large number of pairs already known. The whole -were drawn up into eight catalogues, presented at intervals to the -Astronomical Society, and printed in their Memoirs. A good many of -them would, nevertheless, be rejected by modern astronomers as “not -worth powder and shot,” the stars composing them being too far apart to -give more than an infinitesimal chance of mutual connection. From May -1828 onwards, these measures were made with “South’s _ci-devant_ great -equatorial,” purchased by Herschel. The object-glass, by Tulley, was -five inches in diameter. With a twelve-inch refractor, its successor -in South’s observatory on Campden Hill, Herschel detected, on its -trial-night, February 13, 1830, the sixth star in the “trapezium” of -Orion. This minute object was then about one-third as bright as the -fifth star in the same group, discovered by Robert Hooke in 1664, but -forgotten, and re-discovered by Struve in 1826. A slow gain of light in -Herschel’s star is not improbable. - -He refused, in 1826, to compete for the Lucasian Professorship of -Mathematics at Cambridge. It was practically at his disposal, since all -agreed that no one could better than Herschel have filled the chair -once occupied by Newton. He was, however, disinclined for an University -career, and had undertaken labours incompatible with it. In 1830 he -stood as the “scientific candidate” for the presidentship of the Royal -Society, against the Duke of Sussex. His defeat was by “a ridiculously -small majority.” “I had no personal interest in the contest,” he -wrote to Sir William Hamilton. “Had my private wishes and sense of -individual advantage weighed with me in opposition to what, under the -circumstances, was an imperative duty, I should have persisted in my -refusal to be brought forward; but there are situations where one _has_ -no choice, and such was mine.” - -He made Hamilton’s personal acquaintance at a dinner of notabilities, -given by the Duke of Sussex, in March, 1832. An invitation to Slough -followed, and Hamilton, arriving “in a beautiful star-time,” enjoyed -celestial sights that seemed the opening of a new firmament. - -Herschel married, March 3, 1829, Margaret Brodie, second daughter of -the Rev. Alexander Stewart, of Dingwall, in Ross-shire. The event--not -merely by convention a “happy” one--gave great satisfaction to his -numerous friends. Miss Herschel was beside herself with glad emotion. -“I have spent four days,” she informed him on his wedding-day, “in -vain endeavours to gain composure enough to give you an idea of the -joyful sensation caused by the news. But I can at this moment find no -words which would better express my happiness than those of Simeon: -“Lord, now lettest thou thy servant depart in peace.” But there was -no finality in her desires for this brilliant scion of her race. -His domestic felicity did not long content her; she craved worldly -distinctions. When, after the accession of William IV., a shower of -honours was let fall, she began to think plain “John Herschel, Esq.,” -an address very inadequate to his merits. “Dr. Grosskopf,” the husband -of one of her nieces, “has been _zum Ritter ernannt_ by his present -Majesty,” she wrote discontentedly. “So was Dr. Mükry last week. If all -is betitled in England and Germany, why is not my nephew, J. H., a lord -or a wycount (_sic_) at least? General Komarzewsky used to say to your -father, ‘Why does not King George III. make you Duke of Slough?’” - -An instalment of her wishes was granted by his creation, in 1831, a -Knight of the Royal Hanoverian Guelphic Order; and she lived to see him -a baronet. She had no inkling of his approaching journey to the Cape -when he came to see her in June, 1832, although the visit was designed -as a farewell. Hanover itself, too, had for him an ancestral charm. - -“It was only this evening,” he wrote home, “that, escaping from a -party at Mrs. Beckedorff’s, I was able to indulge in what my soul has -been yearning for ever since I came here--a solitary ramble out of -town, among the meadows which border the Leine-strom, from which the -old, tall, sombre-looking Marktthurm, and the three beautiful lanthorn -steeples of Hanover are seen as in the little picture I have often -looked at with a sort of mysterious wonder when a boy, as that strange -place in foreign parts that my father and uncle used to talk so much -about, and so familiarly. The _likeness_ is correct, and I soon found -the point of view.” - -Almost from the beginning of his surveying operations, Herschel -cherished the hope of extending them to the southern hemisphere. But -during his mother’s lifetime, he took no steps towards its realisation. -The separation would have been cruel. Her death, however, on January -6th, 1832, at the age of eighty-one, removed this obstacle, and -the scheme rapidly took shape. The station originally thought of -was Parramatta, in New South Wales; but Dunlop’s observations there -anticipated him, and he reflected with disappointment that “the cream -of the southern hemisphere had been skimmed” before his turn came. He -learned afterwards that nothing important in the “sweeping” line had -been done at Parramatta; he had virgin skies to explore. A trip to the -Himalayas was his next ambition; and one of the recommendations of the -Cape of Good Hope was its being “within striking distance of India.” -But to India he never went. The Cape was beyond question the most -suitable locality for his purpose, and it would have been waste of time -to have left it, even temporarily, for any other. He was offered a free -passage thither in a ship of war, but preferred to keep his enterprise -altogether on a private footing. So having embarked with his wife, -three children, and instrumental outfit, on board the _Mountstuart -Elphinstone_, he left the shores of England, November 13, 1833. - - - - -CHAPTER VIII. - -EXPEDITION TO THE CAPE. - - -The voyage was prosperous, but long. Nine weeks and two days passed -before the welcome cry of “Land” was heard; and it was in the dawn -of January 15, 1835, that Table Mountain at last stood full in view, -“with all its attendant range down to the farthest point of South -Africa,” outlined, ghost-like, in clear blue. The disembarkation of the -instruments and luggage took several days. They filled fifteen large -boats, and a single onslaught of the south-easterly gale, by which at -that time of the year Cape Town is harried, might easily have marred -the projected campaign. All, however, went well. - -The travellers were welcomed by Dr. Stewart, one of Lady Herschel’s -brothers, and enthusiastically greeted by the Royal Astronomer, Sir -Thomas Maclear. They made no delay in fixing their headquarters. - -“For the last two or three days,” Herschel wrote to his aunt, January -21, “we have been looking for houses, and have all but agreed for one, -a most beautiful place 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 the astonishing brilliancy of the -constellations.” - -“The Grove” resumed its old Dutch name of “Feldhausen” during -Herschel’s occupation of it; and as “Feldhausen” it will always -be memorable in astronomical history as the scene of the first -effective exploration of the southern heavens. The place is -essentially unchanged. Only an avenue of fir-trees has been planted -by way of approach to the house, a solid Dutch structure, with a -disconsolate-looking garden in front; while in an adjacent field, -carpeted with yellow lupins every spring, and redolent of their -perfume, an obelisk has been erected on the former site of the great -reflector. Above, to the west, towers the _gable-end_ of Table -Mountain, and an exuberant growth of oaks and pines softens the -sternness of its “mural precipices.” - -The neighbourhood was, in those days, lonely in the human sense, -although otherwise over- and ill-populated. Wolves and jackals abounded -in the forests; venomous snakes slid through the grass; baboons had the -run of the country; even the lion and the hippopotamus were scarcely -yet extinct in the Cape Peninsula. Many a wild hyæna-shriek startled -the astronomer at his nightly toil; and Dr. Whewell reported that he -had “spent one night in tiger-hunting, but seemed to think it poor -sport compared with the _chasse aux étoiles doubles_.” _Tiger_, it -should be explained, is a local name for a species of leopard: no true -tigers have ever been encountered in Africa. - -His twenty-foot began its activity February 22nd, and the refractor, -which was equatorially mounted in a revolving dome, was ready early -in June. “But I am sorry to say,” he told Miss Herschel, “that the -nights in which it can be used to advantage are rare.” And he lamented -to his brother-in-law and intimate friend, Mr. James C. Stewart, -that, during the hot season, “the stars tremble, swell, and waver most -formidably.” The Cape heavens are indeed often exasperating. On nights -meteorologically quite fine, the dismayed astronomer not uncommonly -sees the stars “walking about” in the field of view; and a mere handful -of cloud will, at other times, with incredible swiftness, spread over -the whole face of the sky. Still, compensation is, sooner or later, -sure to come in a run of magnificent observing weather. This was -Herschel’s experience. He informed Francis Baily, October 23rd, 1834, -that “the definition was far beyond anything experienced in England.” -After rain especially, superb opportunities were afforded, when - - “The starry sequence of nocturnal hours”[G] - - [G] R. Garnett, “Iphigenia in Delphi.” - -might be unbroken, perhaps for a week together, by a single adverse -incident of climate. - -Herschel took three specula with him to the Cape; one made by his -father, another by himself with his father’s aid, and a third, of his -own exclusive manufacture. Their rapid tarnishing kept them in constant -circulation from the tube to the polisher. After half a dozen nights -they had lost all brilliancy; at the end of three months, they were -more than purblind. He acquired, however, such facility and skill in -the use of his polishing machine, that he was able, in 1835, to report -his mirrors as “more perfect than at any former time.” - -He made astonishingly quick progress in observation. On October 24th, -1835, Miss Herschel was informed, “I have now very nearly gone over -the whole southern heavens, and over much of it often. In short, I -have, to use a homely phrase, broken the neck of the work, and my main -object now is to secure and perfect what is done.” - -His sweeps yielded a harvest of 1,202 double stars, and 1,708 nebulæ -and clusters, only 439 of which had been previously registered. Among -the novelties were a faint, delicate miniature of the ring-nebula -in Lyra, and five planetaries. One of these he described as “of a -beautiful greenish-blue colour, a full and intense tint.” This lovely -object, situated in Centaur, is sometimes distinguished as “_the_ blue -planetary”; although its hue is shared by all the members of its class. -The nature of their spectrum, in fact, obliges them to be more or less -green. - -Sir John Herschel applied the term “falcated” to two curious nebulæ -belonging, undoubtedly, to the later recognised “spiral” class. He -perceived besides in oval nebulæ the annular lines of structure -emphasised in Dr. Roberts’s photographs. He remarked, further, that “as -the condensation increases toward the middle, the ellipticity of the -strata diminishes.” - -His study of the Magellanic Clouds gave the first idea of their -composition. He showed them to be aggregations on a vast scale of -every variety of cosmical product. “When examined through powerful -telescopes, the constitution of the Nubeculæ, and especially of the -Nubecula Major, is found to be of astonishing complexity.” He drew up -a preliminary catalogue of 1,163 stars, nebulæ and clusters included -in them, the conjunction of which was really decisive as to nebular -status. For he showed, from the elementary principles of trigonometry, -that, taking the Greater Cloud to be roughly spherical in shape, its -nearest and remotest parts could differ in distance from ourselves -by little more than one-tenth the distance of its centre. The fact -was thus demonstrated that seventh and eighth-magnitude stars and -irresolvable nebulæ co-exist within those limits. He stopped short, -however, of the conclusion drawn by Whewell and Spencer, that the -stellar and nebular sub-kingdoms are not only locally intermixed, but -inseparably united. - -The Magellanic Clouds are the most conspicuous features of the barren -south polar heavens. Round the Lesser Cloud especially, the sky, -Herschel said, “is most oppressively desolate.” And again: “The access -to the Nubecula Minor on all sides is through a desert.” One of the -separate inmates of the Larger Cloud is the “great looped nebula,” -compared by Herschel to “an assemblage of loops,” the complicated -windings of which make it “one of the most extraordinary objects which -the heavens present.” To the eye of the present writer it resembled -a shining strip of cellular tissue hung up against the sky. The -“lace-work nebula” in Cygnus is of the same type; but here the tracery -of nebula is closely followed by a tracery of stars. Truly, “A most -wonderful phenomenon!” as Herschel exclaimed in contemplating it. - -The first photographs of the Magellanic Clouds were taken in 1890–91 -by Mr. Russell of Sydney. They contained an extraordinary revelation. -Both objects came out in them as gigantic spirals. Their miscellaneous -contents are then arranged according to the dictates of a prevalent, -though unexplained cosmical law. The Nubecula Major is a double vortex, -and the extent of its outlying portions, invisible except to the -camera, is at least eight times that of the central mass; but they -conform to the same helical lines. - -Herschel catalogued 1,203 stars strewn over the surface of the famous -Argo nebula, and devoted several months to its delineation. This he -found “a work of great labour and difficulty.” While at the telescope -he often half surrendered to despair “of ever being able to transfer to -paper, with even tolerable correctness, its endless details.” “Language -cannot easily convey,” he said, “a full impression of the beauty and -sublimity of the spectacle this nebula offers when viewed in a sweep, -ushered in by so glorious and innumerable a procession of stars, to -which it forms a sort of climax.” Only the Orion nebula may be thought -to surpass it in “magnitude, complexity, and brightness.” Its most -characteristic feature is an abrupt vacuity, of a “lemniscate oval” -shape, from which it derives the name of the “Keyhole Nebula.” The -value of Herschel’s drawing of this grand object has been accentuated -by its photographic portrayal. Their comparison betrays, in fact, -the occurrence in the interval of what appears to be a vast change. -Already, in 1871, Mr. Russell missed with surprise a prominent feature -in the Feldhausen picture; and its failure to appear on photographic -plates exposed for eight hours, yet impressed with innumerable stars -previously unseen, raised something more than a presumption that, as -Mr. Russell said, “a well-defined and brilliant portion of this nebula -vanished between 1837 and 1871.” Its disappearance was independently -verified by Dr. Gill, Royal Astronomer at the Cape. With a total -exposure of more than twelve hours, in March, 1892, he secured a -magnificent representation of this wonderful object, fundamentally -agreeing with Herschel’s, save only as regards the mass of bright -nebulosity vainly looked for by Mr. Russell. The “swan-shaped” or -“trident-like” structure was clean gone! That is to say, the matter -composing it had ceased to be luminous. It should be added that Mr. -Ranyard, whose special experience lent weight to his opinion, thought -it unsafe to trust much to comparisons of drawings of such baffling -objects, either among themselves or with photographs. - -Before leaving the Cape, Herschel witnessed an event testifying -surprisingly to the _vitality_ of this nebula. In a condensed tract -close to the dark “keyhole,” he was accustomed to see the bright star -Eta Argûs. It gave no sign of being variable until, on December 16, -1837, he perceived with amazement that it had, all at once, nearly -tripled in brightness. After this sudden leap, it mounted gradually -to the level of Alpha Centauri, then slowly declined. It just matched -Aldebaran when Herschel lost sight of it in March, 1838. A second, and -even more vigorous outburst was watched by Sir Thomas Maclear in 1843. -It then overtopped every star except Sirius, and for seven subsequent -years rivalled the splendour of Canopus. No notice was at first taken -of its colour; but it was redder than Mars in 1850, and reddish it -still remains, in its low estate of invisibility to the naked eye. But -since bright lines of hydrogen show in its photographed spectrum, we -may suspect that-- - - “Even in its ashes live its former fires,” - -and that, consequently, its vicissitudes are not yet terminated. The -instability of its character was virtually discovered at Feldhausen. -Except by Burchell, the African traveller, no previous suspicion of -it had been entertained; the numerous facts denoting that the star’s -past behaviour had been abnormal were collected by Sir John Herschel -after it had been caught _in flagrante delicto_. In his belief, it -had no physical connection with, but was merely projected upon, the -nebula. But since then the nebular relations of blazing stars have -been strongly underlined. The mass of circumstantial evidence now -accumulated on the point fully warrants the assertion that Eta Argûs -makes an integral part of the formation it once illuminated. - -A cluster in the constellation of the Cross, unique in the varied and -brilliant tints of its principal components, was compared by Herschel -to “a gorgeous piece of fancy jewellery.” Within the space of 1/48th -part of a square degree, he determined the places of no less than 110 -of them, referred to Kappa Crucis, a rosy orb round which they are -irregularly scattered. The colour-effects in this beautiful ornament of -the sky need large apertures for their full display. - -An object showing to the eye as a hazy star of the fourth magnitude -was entitled by Bayer in 1603 Omega Centauri. Herschel’s twenty-foot -disclosed it as “a noble globular cluster, beyond all comparison the -richest and largest in the heavens.” Dr. Gill obtained an admirable -photograph of it May 25, 1892. The stars composing it are literally -countless. On a plate exposed for two hours at Arequipa, Mr. Solon I. -Bailey reckoned nearly 6,400; yet he made no allowance for those “too -faint and closely packed” to be perceptible except as a “mottled grey -background between the distinct images.” - -Somewhat inferior to Omega Centauri in size, though not at all in -beauty, is 47 Toucani. So obvious is it to the naked eye that, for -several nights after his arrival in Peru, Humboldt took it for a comet. -Central condensation in this cluster appeared to Herschel as if marked -off into three distinct stages; and to his delighted perception the -whole interior offered, by its roseate hue, an exquisite contrast to -the silvery radiance of the outer portions. No other observer has, -however, noticed this chromatic peculiarity. The structure of 47 -Toucani is almost perfectly uniform. It is broken by none of the “dark -lanes,” rifts, or tunnels which so curiously diversify many globular -clusters. The usual hirsute aspect lent by the spreading abroad of -_tentacles_, or radiating stellar streams, is likewise scarcely -distinguishable either in 47 Toucani or Omega Centauri. Indeed, Mr. -Bailey noticed that the photographic images of both were all but -perfectly circular. In a future age this may be otherwise. Streams of -stars will, perhaps, set outward from these grand assemblages, leaving -vacancies behind. Thus, if it be permissible to judge of the relative -antiquity of clusters by their advance towards disruption, 47 Toucani -and Omega Centauri may be reckoned among the youngest of the globular -kind existing in the heavens. - -The mechanism of clusters has received little attention from any -astronomer beside Herschel. And a solution of an ideal case of the -problem it presented was the utmost he could achieve. - -“A quiescent spherical form,” he wrote in 1833, “may subsist as the -bounding outline of an immense number of equal stars, uniformly -distributed through its extent. In such a state of things each star -might describe an ellipse in any plane, and in any direction in that -plane, about the common centre without the possibility of collision. -If the form be not spherical, and the distribution of the stars not -homogeneous, the dynamical relations become too complicated to be -distinctly apprehended.” - -But the more closely these aggregations are examined, the less likely -does it seem that they in any sense represent “quiescent forms.” The -arrangement of the stars composing them rather suggests their being -outward bound into the ocean of surrounding space, although the orders -that they carry are to us sealed. - -Herschel subsequently altered his views regarding the composition -of clusters, and threw out in 1847 “the possibility of masses of -luminous matter--of whatever density or rarity, of whatever bulk or -minuteness--forming a connected system, and being prevented from -collapse or from mutual interference by the resistance of a transparent -and non-luminous medium.” For a “dynamical” he, in short, substituted -a “statical equilibrium,” the interposed medium lending unity to the -mixed aggregate, and enabling it to rotate, as a whole, upon an axis. -But the rotation is more than questionable. It seems to be precluded -by the ragged contours and indeterminate boundaries of all starry -collections. Photographic evidence, on the other hand, favours Sir John -Herschel’s surmise as to the composite nature of clusters. Some at -least evidently unite within themselves the “two sidereal principles.” -The stellar points they mainly consist of are immersed in, or linked -together by, shining nebulous stuff. - -Herschel provided a southern sequel to his father’s star-gauging work -by counting 70,000 stars in 2,300 fields. Their distribution was in -complete accordance with the results of the earlier experiments. -“Nothing can be more striking,” Sir John wrote, “than the gradual, -but rapid increase of density on either side of the Milky Way as we -approach its course.” The existence of an “ecliptic of the stars” (in -Lambert’s almost prophetic phrase) was demonstrated. Or, as Herschel -himself put it, the plane of the Galaxy “is to sidereal, what the -ecliptic is to planetary astronomy, a plane of ultimate reference, the -ground-plan of the sidereal system.” He estimated, from the basis of -his gauge-reckonings, that his twenty-foot reflector was capable of -showing, in both hemispheres, about five and a half million stars. The -smallest of these would be of 14·5 magnitude, on the strict photometric -scale. But, unless his valuation was greatly too small, there must -be a conspicuous falling off in stellar density beyond the region of -tenth or eleventh magnitude. If this be so, scarcely one-quarter of -the expected stars will make their appearance on the plates of the -International Survey. - -The grand feature of southern celestial scenery is the splendour of the -Milky Way. One of the galactic condensations in Sagittarius actually -seems to start out from the sky in a definite globular form; and the -darkness of the great rift beginning near the Cross is so intensified -by contrast with the strongly luminous branches it separates, as to -throw the blackness of the exterior heavens _into the shade_. This -part of the Milky Way may even be seen in southern latitudes--as it -was by the present writer--reflected from a glassy ocean-surface. The -section passing from Centaur through the Ship to Orion is, in some -respects, still more striking. Captain Jacob remarked at Madras that -“the general blaze from this portion of the sky is such as to render -a person immediately aware of its having risen above the horizon, -though he should not be at the time looking at the heavens.” Herschel -commented on the singular interruptions of the shining zone by obscure -spaces in Scorpio, near Alpha Centauri, and elsewhere; and admired -the enhancement afforded to its magnificence by “a marvellous fringe -of stars” attached pretty regularly to its southern border. “It is -impossible,” he wrote to Sir William Hamilton in June, 1836, “to resist -the conviction that the Milky Way is not a stratum, but a ring.” - -His telescopic analysis disclosed in it a variety and complexity of -structure for which he was wholly unprepared. “Great cirrous masses -and streaks” of galactic light presented themselves in Sagittarius; -and, as the telescope moves, the appearance is that of clouds passing -in a _scud_.” “The Milky Way,” he continued, “is like sand, not strewn -evenly as with a sieve, but as if flung down by handfuls, and both -hands at once, leaving dark intervals, and all consisting of stars -of the lowest magnitudes,” down to nebulosity, in a most astonishing -manner.” As he proceeded, the stars became “inconceivably numerous and -minute. There must be millions on millions, and all most unequally -massed together; yet they nowhere run to nuclei, or clusters much -brighter in the middle.” - -In some regions, the formation proved unfathomable; all traces of -stellar _texture_ disappeared. In others, it was plainly perceived to -consist of portions differing exceedingly in distance, but brought by -projection into nearly the same visual line. Near the Trifid Nebula, -“we see foreshortened,” he said, “a vast and illimitable area scattered -over with discontinuous masses and aggregates of stars, in the manner -of the cumuli of a mackerel-sky, rather than of a stratum of regular -thickness and homogeneous formation.” - -These varied observations compelled him to reject decisively Olbers’s -hypothesis of light-extinction in space. For, if the possible range of -ethereal messages be restricted in one direction, it must be equally -restricted in all. “We are not at liberty,” he reasoned, “to argue that -in one part of the circumference of the galaxy our view is limited by -this sort of cosmical veil which extinguishes the smaller magnitudes, -cuts off the nebulous light of distant masses, and closes our view in -impenetrable darkness; while, at another, we are compelled, by the -clearest evidence telescopes can afford, to believe that star-strewn -spaces _lie open_, exhausting their powers and stretching out beyond -their utmost reach.” These objections seem fatal to what we may -call the “agnostic” theory of the sidereal world--the theory that -investigations into its construction are for ever barred by failure -of the means of communication--that we can never see more than a -necessarily meaningless part of a possibly infinite, and, in any case, -absolutely inscrutable whole. - -The general telescopic exploration of the Milky Way began and ended -with the Herschels. Their great reflectors have been superseded by -the photographic camera. This particular application of its versatile -powers encountered special difficulties; but they were happily -overcome by Professor Barnard in July, 1889. A six-inch portrait -lens afforded the two chief requisites of a powerful light-grasp and -an extensive field; and plates exposed with it for some three hours -showed accordingly, for the first time, “in all their delicacy and -beauty” (to quote Professor Barnard’s words), “the vast and wonderful -cloud-forms, with their remarkable structure of lanes, holes, and black -gaps, and sprays of stars, as no eye or telescope can ever hope to see -them.” The work has since been continued by him and others, notably -by Mr. Russell at Sydney, and by Professor Max Wolf at Heidelberg, -so that the complete round of the “circling zone” will, before long, -have its varied aspects permanently recorded. They frequently present -strange and significant forms. Branching, leaf-like, spiral, elliptical -structures abound; individual stars are disposed in circlets, streams, -parallel rows, curves of sundry kinds. A “clustering power” of unknown -nature is ubiquitously active; orderly development is in progress. -A creative purpose can be _felt_, although it cannot be distinctly -followed by the mind. - -Herschel’s “sweeps” in southern skies were continued until January, -1838; but with frequent intermissions. He was ready for every -interesting object that came in his way--comets among the rest. -“Encke’s--_yours_,” he informed his aunt, October 24, 1835, “escaped me -owing to trees and the Table Mountain, though I cut away a good gap in -our principal oak avenue to get at it.” Four days later he caught sight -of Halley’s comet at its second predicted return. But for the stellar -aspect of this body his observations of it would have begun much -earlier; for, in the absence of an exact ephemeris, it was impossible -to pick it out from among the stars it long precisely counterfeited. -“I am sure,” he said, “that I must often have swept with a night-glass -over the very spot where it stood in the mornings before sunrise; and -never was surprise greater than mine at seeing it riding high in the -sky, broadly visible to the naked eye, when pointed out to me by a note -from Mr. Maclear, who saw it with no less amazement on the 24th.” - -“This comet,” he wrote to Miss Herschel, March 8, 1836, “has been a -great interruption to my sweeps, and I _hope_ and _fear_ it may yet -be visible another month.” It lingered on just two. He watched with -astonishment the changes it underwent. “Within the well-defined head,” -he wrote in his “Cape Observations,” “and somewhat eccentrically -placed, was seen a vividly luminous nucleus, or rather, an object -which I know no better way to describe than by calling it a miniature -comet, having a nucleus, head, and tail of its own, perfectly distinct, -and considerably exceeding in intensity of light the nebulous disc or -envelope.” - -This strangely organised body was a very Proteus for instability of -form. It alternately lost and recovered its tail. It contracted into -the likeness of a star, then dilated into a nebulous globe, which -at last vanished as if through indefinite diffusion. The whole mass -“seemed touched, seemed turned to finest air.” During one week at -the end of January--it had passed perihelion November 16--Sir John -estimated that the cometary Amœba had increased its bulk no less than -forty times! - -The paraboloidal form characteristic of this comet and many others, was -to him “inconceivable,” apart from the play of repulsive, in addition -to attractive forces; and he suggested that high electrical excitement -due to vaporisation, if of the same kind with a permanent charge on -the sun, would plausibly account for the enigmatical appearances he -had witnessed. From their close study at Königsberg, Bessel had -already concluded “the emission of the tail to be a purely electrical -phenomenon.” - -In March, 1836, Herschel attacked the subject of southern stellar -photometry. Carrying further the “method of sequences,” he determined -the relative brightness of nearly five hundred stars, which he disposed -in order on a single descending scale, and linked on by careful -comparisons to the northern stars, as they “lightened into view” on the -homeward voyage. By the device of an “artificial standard star,” he was -besides enabled to obtain numerical values for the lustre of each star -examined, in terms of that of Alpha Centauri. Most important of all, he -rectified the current system of magnitudes, and introduced a definite -“light ratio,” which has since been extended, and more strictly -defined, but not altered. - -His “astrometer” gave Herschel the means of _balancing_ the lustre of -Alpha Centauri against full moonlight. The latter proved to be 27,500 -times more powerful. And Wollaston having determined the ratio of -moonlight to sunlight at 1/800000 (corrected by Zöllner to 1/600000), -it became feasible to compare the brightness of any particular star, -_as we see it_, with the brightness of the sun. Alpha Centauri, for -example, sends us, according to Herschel, 1/22 thousand millionth of -the light we receive from our domestic luminary. Moreover, when the -distance of the star came to be measured (it amounts to twenty-five -billions of miles), _light received_ could at once be translated into -_light emitted_. And the result has been to show that the components of -this splendid binary are, taken together, four times more luminous than -the sun. Through Sir John Herschel’s photometric researches, then, the -real light-power of stars at known distances became an ascertainable -quantity; and it is an element of great importance to astrophysical -inquiries. - -On January 10, 1837, he wrote from Feldhausen to his brother-in-law: -“I am now at work on the spots in the sun, and the general subject -of solar radiation.” The sun was just then at an exceptionally high -maximum of disturbance. Spots of enormous size frequently obscured -its disc. One was estimated by Herschel, March 29, 1837, to cover, -independently of others, an area of 3,780 millions of square miles. So -that it considerably exceeded in dimensions the great spot-group of -February, 1892, the largest ever photographed at Greenwich. The study -of a series of such phenomena led him to propound the “cyclone-theory” -of their origin. It marked a decided advance in solar physics, if -only because it rested upon the fact--until then unaccountably -overlooked--that spot-production is intimately connected with the -sun’s rotation. He regarded it as a kind of disturbance incidental to -a system of fluid circulation analogous to the terrestrial trade- and -anti-trade winds. “The spots,” he said, “in this view of the subject -would come to be assimilated to those regions on the earth’s surface -where, for the moment, hurricanes and tornadoes prevail; the upper -stratum being temporarily carried downwards, displacing by its impetus -the two strata of luminous matter beneath, the upper of course to a -greater extent than the lower, and thus wholly or partially denuding -the opaque surface of the sun below.” - -But the fundamental cause of our atmosphere’s flow and counter-flow -is absent in the sun. The earth is heated from the outside, and -therefore unequally; hence the air rushes along, turning westward -as it goes, from the chilly poles to the torrid zone of vertical -sunshine. No reason is, however, apparent why the solar equator should -be hotter than the solar poles. That adduced by Herschel is certainly -inadequate. He supposed that, by a retention of heat at the equator due -to the accumulation there, consequent upon his rotation, of the sun’s -absorbing atmosphere, a difference of temperature might be maintained -sufficient to keep the solar trade-winds blowing. But the effect is too -slight to be detected. And, in fact, the main drift of the photospheric -layers is along parallels of latitude. Polar and equatorial currents -are insignificant and uncertain. - -Herschel and Pouillet contemporaneously, although at opposite sides -of the globe, succeeded in 1837 in measuring the intensity of solar -radiation. They were the first to apprehend the true bearings of the -question, which in principle are simple enough. All that is required -is to determine the heating effects, in a given time, of direct -sunshine. Its despoilment by our air has, indeed, to be allowed for. -Here the chief element of uncertainty comes in. Herschel put the loss -at one-third the original thermal power of vertical rays; Pouillet -pronounced it nearly one-half; Langley, using the most refined -appliances, concludes it to be four-tenths. Striking an average between -his own and the French results, Herschel calculated that, at the sun’s -surface, a shell of ice forty feet thick would melt in one minute, the -rate being reduced, at the distance of the earth, to an inch in two -hours and twelve minutes. And it is now practically certain that this -estimate was too small by about half its amount. - -By way of illustrating the effects obtained with his philosophical -apparatus, he constructed a popular kind of actinometer, in the shape -of an “American dispatch,” made of a few pieces of wood and two panes -of glass, in which eggs were roasted, and beef-steaks broiled, by -sun-heat alone. The viands thus _cosmically cooked_ were “eaten with no -small relish by the entertained bystanders.” - -Mimas and Enceladus, Saturn’s innermost moons, had persistently eluded -Herschel’s search for them in England; but, to his great delight, both -favoured him at the Cape. His observations of them in 1835–6 were the -first since his father’s time. The next detection of Mimas was by Mr. -Lassell in 1846. - -The extent, variety, and completeness of the work done at Feldhausen -strike one with ever-fresh admiration. It seems scarcely credible that -so much was accomplished in four years by a single unaided individual. -Herschel’s only assistant was an honest mechanic named John Stone, -faithful, serviceable, in his way skilful, but not a “being” of the -“quick as lightning” sort, imagined and realised by Caroline Herschel. -It is related that during his observations of Halley’s comet, Sir John -on one occasion fell asleep, and while he remained in this condition -of peril (owing to the elevation and insecurity of his perch), Stone -kept dutifully turning the telescope. At last the astronomer awoke, -rubbed his eyes, looked down the great tube, saw nothing, rubbed his -eyes again, and exclaimed, “Why, John, where’s the comet?” The comet -had meantime set, and the telescope was duly directed towards its place -behind Table Mountain! - -The splendid fulfilment of his astronomical tasks did not represent -the whole of Herschel’s activity at the Cape. He collected a large -store of tidal data for Dr. Whewell; started scientific meteorology; -established a system of national education still working beneficially, -and presided over the South African Literary and Scientific -Institution, the members of which presented him with a gold medal on -his departure. His visit made an epoch in the development of the Colony. - -To himself personally it was a time of intense enjoyment. His labours, -arduous though they were, proceeded calmly, disembarrassed from -jostling claims and counter-claims. They were carried on with absorbed -enthusiasm, inspired in part by their sublime nature, in part by the -excitement of novelty. His family throve and multiplied at Feldhausen. -Sir Thomas Maclear’s friendship supplied unfailing social pleasure. An -exhilarating climate, moreover, enchanting scenery, translucent skies, -blossoming glens and hillsides worthy of Maeldune’s Isle of Flowers, -contributed to render his southern sojourn a radiant episode. He wrote -of it to Mr. Stewart as “the sunny spot in my whole life, where my -memory will always love to bask.” But “the dream,” he added, “was too -sweet not to be dashed by the dread of awakening.” The spell was broken -when in the middle of March, 1838, he sailed in the _Windsor Castle_ -for England. - -The interest created by his romantic expedition spread to the other -side of the Atlantic. A grotesque narrative, published in the _New -York Sun_ for September, 1835, of lunar discoveries made at the Cape -with the combined aid of the twenty-foot reflector and the Drummond -limelight, was eagerly read and believed by thousands, was reprinted, -re-circulated, and re-read. Nor were common gulls the only victims -to the hoax. The truth of the story was gravely debated by the Paris -Academy of Sciences. - -Herschel’s home-coming was a triumph. He was overwhelmed with applause -and gratulation. His fellow-countrymen offered him what compensation -they could for the disappearance from his horizon of the Southern -Cross. He was created a baronet at the Queen’s Coronation, received -an honorary degree of D.C.L. at Oxford in 1839, and was offered, but -declined, reimbursement from the Treasury for the entire cost of his -trip. He peremptorily refused as well to represent the University of -Cambridge in Parliament, or to be nominated for the Presidentship of -the Royal Society. His utmost desire was for a quiet and laborious -life. A banquet, however, given in honour of his return, June 15, -1838, could not be shunned; the less so that the celebration had a -typical character. “In honouring a man,” Sir William Hamilton said, in -proposing his health, “we honour science too.” For “the cultivators and -lovers of Science have chosen Herschel for their chief--say, rather, -have as such received him by inheritance.” - - - - -CHAPTER IX. - -LIFE AT COLLINGWOOD. - - -Herschel’s career as an observing astronomer came to a virtual end with -his departure from the Cape. He was then forty-six, two years younger -than his father when he began his course of prodigious activity at -Slough. Sir William’s craving to see and to know was insatiable; Sir -John’s was appeased by the accomplishment of one grand enterprise. His -was a many-sided mind; dormant interests of sundry kinds revived on the -first opportunity; new ones sprang up; and curiosity to interrogate the -skies ceased to “prick the sides of his intent.” So the instruments -taken down at Feldhausen in 1838 were not remounted in England; and -their owner is never again recorded to have used a telescope. One -cannot but regret that, in the plenitude of his powers, and instructed -by rare experience, he should have put by his weapons of discovery.[H] -The immense stock of observations with which they had furnished him -remained, it is true, in their primitive, rough-hewn state; and he may -have considered that wise husbandry required him to save one harvest -before planting another. This, at any rate, was the course that he -pursued. - - [H] The three specula of the twenty-foot are in the possession - of Sir William J. Herschel; the tube remains in good - preservation at Collingwood. - -But it was often and in many ways interrupted. The demands on his -time and thoughts were innumerable. Having settled his family -for the season in London, he paid his third and last visit to his -venerable aunt, and, in returning, dined with Dr. Olbers, the -physician-astronomer of Bremen, then in his eightieth year. A fortnight -later he was on his way to Newcastle, where the British Association -met, August 20th. He was received with acclamation, but overwhelmed -by scientific exactions. The proceedings were to him “a dreadful wear -and tear,” and they left behind “mixed and crowded recollections.” No -wonder. Besides acting as President of the Mathematical Section, he -found himself involved in varied responsibilities. He was placed on a -Committee for bringing down to date the places of Lacaille’s 10,000 -southern stars; on another for revising stellar nomenclature. The -reduction of a body of meteorological observations made on a plan of -his devising was entrusted to him; above all, he was charged with the -development of Humboldt’s international scheme for securing systematic -and world-wide observations on terrestrial magnetism. He drew up a -memorial to the Government; compiled the Instructions for Sir James -Clark Ross’s Antarctic expedition; and elaborately reported progress -at several successive meetings of the British Association. His heart -was in the work. He contributed an article dwelling on its importance -to the _Quarterly Review_ for June, 1840; and in 1845 he expressed the -opinion that “terrestrial physics form a subject every way worthy to be -associated with astronomy as a matter of universal interest and public -support.” - -The constellations gave him still more trouble than the vagaries of -poised needles. They were in a riot of disorder. Celestial maps had -become “a system of derangement and confusion”--of confusion “worse -confounded.” New asterisms carved out of old existed precariously, -recognised by some, ignored by others; waste places in the sky had -been annexed by encroaching astronomers as standing-ground for their -glorified telescopes, quadrants, sextants, clocks; a chemical apparatus -had been set up by the shore of the river Eridanus, itself a meandering -and uncomfortable figure; while serpents and dragons trailed their -perplexing convolutions through hour after hour of right ascension. -There were constellations so large that Greek, Roman, and Italic -alphabets had been used up in designating the included stars; there -were others separated by debatable districts, the stars in which often -duplicated those situated within the authentic form of one of the -neighbouring celestial monsters. Identification was thus in numberless -cases difficult; in some, impossible. - -In conjunction with Francis Baily, Herschel undertook the almost -hopeless task of rectifying this intolerable disorder. After much -preliminary labour, he submitted to the Royal Astronomical Society, -in 1841, a drastic scheme of constellational reform--a stellar -redistribution-bill, framed on radical principles. Its alarming -completeness, however, caused it to be let drop; and he finally -proposed, in his report of 1844 to the British Association, a less -ambitious but more practicable measure. Although not adopted in its -entirety, it paved the way for ameliorations. The boundaries of -the constellations have since been defined; interlopers have been -ejected; one--the Ship Argo--especially obnoxious for its unwieldy -dimensions, has been advantageously trisected. Nevertheless, individual -star-nomenclature grows continually more perplexed; partial systems -have become intermingled and entangled; double stars are designated in -one way, variables in another, quick-moving stars in a third, red stars -in a fourth, while any one of many catalogue-numbers may be substituted -at choice; palpable blunders, unsettled discrepancies, anomalies of -all imaginable kinds, survive in an inextricable web of arbitrary -appellations, until it has come to pass that a star has often as many -aliases as an accomplished swindler. - -In the spring of 1840 Herschel removed from Slough to Collingwood, -a spacious country residence situated near Hawkhurst, in Kent. Here -he devoted himself, in good earnest, to the preparation of his Cape -results for the press. It was no light task. The transformation of -simple registers of sweeps into a methodical catalogue is a long and -irksome process; and Herschel was in possession of the “sweepings” -of nearly four hundred nights. He executed it single-handed, being -averse to the employment of paid computers. This was unfortunate. -Monotonous drudgery was not at all in his line; as well put Pegasus -between shafts. He had always found in himself “a great inaptitude” -for numerical calculations; and he now acknowledged to Baily that -attention to figures during two or three consecutive hours distressed -him painfully. Whewell lamented in the _Quarterly Review_ the lavish -expenditure of his time and energy upon “mere arithmetic”--computations -which a machine would have been more competent to perform than a -finely organised human brain. At last, however, in November, 1842, the -necessary reductions were finished; and the letterpress to accompany -the catalogues of double stars and nebulæ left his hands a couple of -years later. The preparation of the plates occasioned further vexatious -delays; and it was not until 1847 that the monumental work entitled -“Results of Astronomical Observations at the Cape of Good Hope” issued -from the press. The expenses of its production were generously defrayed -by the Duke of Northumberland. In sending a copy to his aunt, then in -her ninety-eighth year, he wrote: “You will have in your hands the -completion of my father’s work--‘The Survey of the Nebulous Heavens.’” -The publication was honoured with the Copley Medal by the Royal -Society, and with a special testimonial by the Astronomical Society. - -Bessel, the eminent director of the Königsberg observatory, made -Herschel’s personal acquaintance at the Manchester meeting of the -British Association in 1842, and paid him a visit at Collingwood. The -subject of a possible trans-Uranian planet was discussed between them. -The German astronomer regarded its existence as certain, and disclosed -the plot he had already formed for waylaying it on its remote path. The -premonition stirred Herschel deeply. “There ought to be a hue and cry -raised!” he exclaimed in a letter to Baily. And in resigning the Chair -of the British Association, September 10, 1846, he spoke with full -assurance of the still undiscovered body. “We see it,” he declared, -“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 that of ocular demonstration.” Within a -fortnight, Neptune, through Le Verrier’s indications, was captured at -Berlin. - -“I hope you agreed with me,” he wrote, November 19, 1846, to Sir -William Hamilton, “that it is perfectly possible to do justice to -Adams’s investigations without calling in question M. Le Verrier’s -_property_ in his discovery. The fact is, I apprehend, that the -Frenchmen are only just beginning to be aware _what a narrow escape Mr. -Neptune had of being born an Englishman_. Poor Adams aimed at his bird, -it appears, first, and as well as Le Verrier, but his gun hung fire, -and the bird dropped on the other side of the fence!” - -It is well known that Le Verrier and Adams personally ignored -controversy as to their respective claims to the planetary _spolia -opima_. They were together at Collingwood in July, 1847, with Struve as -their fellow-guest. During those few days King Arthur (in the person of -Sir John Herschel) “sat in hall at old Caerleon.” - -He was elected President of the Royal Astronomical Society for the -usual biennial term in 1828, 1840, and 1847; on the last occasion -through the diplomatic action of Professor De Morgan. The Society -was passing through a crisis; he apprehended its dissolution, and -judged that it could only be saved by getting Herschel’s consent to -become its nominal head. “The President,” he wrote to Captain Smyth, -“must be a man of brass (practical astronomer)--a micrometer-monger, -a telescope-twiddler, a star-stringer, a planet-poker, and a -nebula-nabber. If we give bail that we won’t let him do anything if he -would, we shall be able to have him, I hope. We must all give what is -most wanted, and his name is even more wanted than his services. We can -do without his services, not without loss, but without difficulty. I -see we shall not, without great difficulty, dispense with his name.” - -And to Herschel himself: “We have been making our arrangements for -the Society for the ensuing year; and one thing is that you are not -to be asked to do anything, or wished to do anything, or wanted to do -anything. But we want your _name_.” It was lent; and its credit seems -to have had the desired effect. - -Dr. Whewell vainly tried to inveigle him, in November, 1838, into -accepting the presidentship of the Geological Society; but he had to -submit, in 1842, to be elected Rector of Marischal College, Aberdeen; -and he consented to preside over the meeting of the British Association -at Cambridge in June, 1845. His dignity on the occasion was not allowed -to interfere with his usefulness. He wrote home June 22: “We have been -on the Magnetic Committee working hard all the morning, in a Babel of -languages and a Babylonian confusion of ideas, which crystallised into -something like distinctness at last.” By that time the long-desired -particulars regarding terrestrial magnetism were rapidly accumulating. -_Facts_, as Herschel announced from the Presidential Chair, were -plentifully at hand. “What we now want is _thought_, steadily directed -to single objects, with a determination to avoid the besetting evil -of our age--the temptation to squander and dilute it upon a thousand -different lines of inquiry.” - -Herschel observed the great comet of 1843 from the roof of his house -at Collingwood, on March 17, the first evening of its visibility in -England. All that could be seen was “a perfectly straight narrow band -of considerably bright, white cloud, thirty degrees in length, and -about one and a half in breadth.” It was not until the following night -that he recognised in this strange “luminous appearance” “the tail of -a magnificent comet, whose head at the times of both observations was -below the horizon.” - -In December, 1850, he was appointed Master of the Mint--a position -rendered especially appropriate to him by Newton’s prior occupation of -it. The duties connected with it were just then peculiarly onerous. -Previously of a temporary and political character, the office now -became permanent, and simply administrative. Many other changes -accompanied this fundamental one. “The whole concern,” he said, “is in -process of reorganisation.” This fresh start demanded much “personal -and anxious attendance.” Notwithstanding his anxious regard for the -interests of subordinates, the reconstruction could not but be attended -by serious friction. No amount of oiling will get rusty wheels to -revolve smoothly all at once. “Things progress rather _grumpily_,” he -reported privately, “owing to the extreme discontent of some parties.” -Further contentious business devolved upon him as a member of the -jury on scientific instruments at the Great Exhibition. His time was -fully and not agreeably occupied. Rising at six, he worked at home -until half-past nine, then hurried to the Mint, which he exchanged -between three and four o’clock for the Exhibition, and there, until the -closing of its doors, examined the claims, and appeased the quarrels of -rival candidates for distinction. He also sat on the Royal Commission -appointed in 1850 to inquire into the University system. Its -recommendations, agreed to by him in 1855, greatly disgusted Whewell; -but their friendship remained unaltered by this discordance of opinion. - -These accumulated responsibilities were too much for Herschel’s -sensitive nature; and the burthen was made heavier by a partial -separation from his family. He was never alone in Harley Street, but -the joyous life of Collingwood could not be transported thither; -and the arid aspect of a vast metropolis, suggesting business and -pleasure in excess, but little of enjoyment in either, oppressed him -continually. His health suffered, and in 1855 he withdrew definitively -into private life. His resignation of the Mint was most reluctantly -accepted. - -“I find,” playfully remarked De Morgan, “that Newton and Herschel added -each one coin to the list: Newton, the gold quarter-guinea, which was -in circulation until towards the end of the century; Herschel, the gold -quarter-sovereign, which was never circulated.” - -It was not the repose of inaction that Herschel sought at Collingwood. -“Every day of his long and happy life,” Professor Tait said truly, -“added its share to his scientific services.” Thenceforward he devoted -himself chiefly to the formidable task of collecting and revising -his father’s results and his own. His “General Catalogue of Nebulæ,” -published in the _Philosophical Transactions_ for 1864, was in itself -a vast undertaking. It comprised 5,079 nebulæ and clusters, to which -it served as a universal index of reference. It averted the mischief -of duplicate discoveries, settled the sidereal status of many a -pseudo-comet, and quickly became the authoritative guide of both -comet- and nebula-hunters. In the enlarged form given to it by Dr. -Dreyer in 1888, it is likely long to hold its place. Herschel next, in -1867, amalgamated into a regular catalogue of 812 entries his father’s -various classed lists of double stars (Memoirs, Royal Astronomical -Society, xxxv.). A far more comprehensive work was then taken in hand. -He desired to do for double stars what he had done for nebulæ--to -compile an exhaustive register of them in the shape of a catalogue, -accompanied by a short descriptive account of each pair. But he was not -destined to put this coping-stone to the noble monument erected by his -genius. Strength failed him to digest and dispose the immense mass of -materials he had collected. Nor was it possible for another to gather -up the loose threads of his unfinished scheme. All that could be done -was to preserve the imposing fragment as he left it. An ordered list -of the 10,320 multiple stars he had proposed to treat was accordingly -published in the fortieth volume of the same Society’s _Memoirs_ under -the care of Professor Pritchard and Mr. Main. But it hardly possesses -more than a commemorative value. - -Maria Edgeworth was an old friend of Sir John Herschel’s. In March, -1831, she paid him a three days’ visit at Slough, which, she told a -friend in Ireland, “has far surpassed my expectations, raised as they -were, and warm from the fresh enthusiasm kindled by his last work” (the -“Preliminary Discourse”). Mrs. Herschel she described as “very pretty,” -sensible, and sympathetic, and possessed of the art of making guests -happy without effort. On Sunday, after service, the philosopher showed -off the dazzling colour-effects of polarised light, and at night, -with the twenty-foot, “Saturn and his rings, and the moon and her -volcanoes.” - -After twelve years, she came again, this time to Collingwood. “I should -have written before,” Herschel assured Sir William Hamilton, December -1st, 1843, “but Miss Edgeworth has been here, and that, among all -people who know how to enjoy her, is always considered an excellent -reason for letting correspondence and all other worldly things ‘gang -their ain gate.’ She is more truly admirable now, I think, than at any -former time, though in her seventy-fifth year.” - -Maria herself wrote from Collingwood in the following spring: “Here are -Lord and Lady Adare, Sir Edward Ryan, and ‘Jones on Rent.’ Jones and -Herschel are very fond of one another, always differing, but always -agreeing to differ, like Malthus and Ricardo.” - -Sir William Hamilton spent a week under the same hospitable roof in -1846. He was delighted, and, as was his wont, compressed the expression -of his pleasure “within the Sonnet’s scanty plot of ground.” In the -first of a pair entitled “Recollections of Collingwood,” he celebrated -the “thoughtful walk” with his host, and the “social hours” in a family -circle, - - “Where all things graceful in succession come; - Bright blossoms growing on a lofty stalk, - Music and fairy-lore in Herschel’s home.”[I] - - [I] The lines are quoted in Graves’s “Life of Hamilton,” vol. - ii. p. 525. - -The second dealt with “high Mathesis,” and - - “dimly traced Pythagorean lore; - A westward-floating, mystic dream of FOUR.” - -Although not, like his friend, an incorrigible and impenitent -sonnetteer, Herschel was “very guilty” of at least one specimen of the -art. They were staying together, in June, 1845, at Ely, in the house of -Dean Peacock. Hamilton’s inevitable sonnet came duly forth, and “next -morning,” he related to De Morgan, “as my bedroom adjoined Herschel’s, -and thin partitions did my madness from his great wit divide, I easily -heard what Burns might have called a ‘crooning,’ and was not much -surprised (being familiar with the symptoms of the attack)[J] when, -before we sat down to breakfast at the Deanery, Lady Herschel handed -me, in her husband’s name and her own, a sonnet of _his_ to _me_, -which, unless the spirit of egotism shall seize me with unexpected -strength, I have no notion of letting you see.” - - [J] “Aut insanit, aut versos facit.” - -The circulation of Herschel’s fervid eulogy would assuredly have put -his modesty to the blush. Headed “On a Scene in Ely Cathedral,” it runs -as follows:-- - - “The organ’s swell was hushed, but soft and low - An echo, more than music, rang; when he, - The doubly-gifted, poured forth whisperingly, - High-wrought and rich, his heart’s exuberant flow - Beneath that vast and vaulted canopy. - Plunging anon into the fathomless sea - Of thought, he dived where rarer treasures grow, - Gems of an unsunned warmth and deeper glow. - O born for either sphere! whose soul can thrill - With all that Poesy has soft or bright, - Or wield the sceptre of the sage at will - (That mighty mace which bursts its way to light), - Soar as thou wilt!--or plunge--thy ardent mind - Darts on--but cannot leave our love behind.” - -Of Hamilton’s abstruse invention, the method of “Quaternions” (here -alluded to), Herschel was, from the first, an enthusiastic admirer. -He characterised it in 1847 as “a perfect cornucopia, from which, turn -it on which side you will, something rich and valuable is sure to drop -out.” The “power and pregnancy” of the new calculus were supremely -delightful to him, and he advised every mathematician to gain mastery -over it as a “working tool.” As such it has not yet been brought into -ordinary use, yet it remains in the armoury of science, ready for -emergencies. - -Miss Mitchell of Nantucket, the discoverer of a comet, and a professor -of astronomy, published in 1889 (in the _Century_ magazine) her -reminiscences of a short stay at Collingwood in 1858. Her host “was -at that time sixty-six, but he looked much older, being lame and much -bent in his figure. His mind, nevertheless, was full of vigour. He -was engaged in re-writing the ‘Outlines of Astronomy.’” “Sir John’s -forehead,” she says, “was bold but retreating; his mouth was very good. -He was quick in motion and in speech. He was remarkably a gentleman; -more like a woman in the instinctive perception of the wants and wishes -of a guest.” - -“In the evening,” she relates, “we played with letters, putting out -charades and riddles, and telling anecdotes, Sir John joining the -family party and chatting away like the young people.” He propounded -the question: If one human pair, living in the time of Cheops, had -doubled, and their descendants likewise, once every thirty years, could -the resulting population find room on the earth? The company thought -not. “But if they stood closely, and others stood on their shoulders, -man, woman, and child, how many layers would there be?” “Perhaps -three,” replied Miss Mitchell. “How many feet of men?” he insisted. -“Possibly thirty.” “Enough to reach to the moon,” said his daughter. -“To the sun,” exclaimed another. “More, more!” cried Sir John, exulting -in the general astonishment. “To Neptune,” was the next bid. “Now you -burn,” he allowed. “_Take one hundred times the distance of Neptune, -and it is very near._” “That,” he added, “is my way of whitewashing -war, pestilence, and famine.” - -He further entertained his American guest with accounts of the -paradoxical notions communicated to him by self-taught or would-be -astronomers. One had inferred the non-existence of the moon from -Herschel’s chapters on lunar physics and motions. Another enclosed -half-a-crown for a horoscope. A third wrote, “Shall I marry, and have -I seen her?” In reference to the efforts then being made to introduce -decimal coinage into England, he remarked, “We stick to old ways, but -we are not cemented to them.” - -The portrait of Caroline Herschel, painted by Tielemann in 1829, -which she herself declared to “look like life itself,” hung in the -drawing-room. (It is that reproduced in this volume.) “You would say in -looking at it,” Miss Mitchell wrote, ‘she must have been handsome when -she was young.’ Her ruffled cap shades a mild face, whose blue eyes -were even then full of animation. But it was merely the beauty of age.” - -Herschel was no exception to the rule that astronomers love music -and flowers. He was never tired of gardening, and--to quote James -Nasmyth--“his mechanical and manipulative faculty enabled him to take a -keen interest in all the technical arts which so materially aid in the -progress of science.” The manufacture of specula naturally came home -to him, and he watched with genuine pleasure Nasmyth’s grinding and -polishing operations. He spent several days with him at Hammerfield in -1864. “Of all the scientific men I have had the happiness of meeting,” -Nasmyth wrote in his “Autobiography,” “Sir John stands supremely at -the head of the list. He combined profound knowledge with perfect -humility. He was simple, earnest, and companionable. He was entirely -free from assumptions of superiority, and, still learning, would listen -attentively to the humblest student. He was ready to counsel and -instruct, as well as to receive information.” - -Herschel’s correspondence with De Morgan extended over nearly forty -years, and became latterly of an intimate character. “Looking back on -our long friendship,” he wrote to the widow shortly after De Morgan’s -death in the spring of 1871, “I do not find a single point on which we -failed to sympathise; and I recall many occasions on which his sound -judgment and excellent feeling have sustained and encouraged me. Many -and very distinct indications tell me that I shall not be long after -him.” - -It fell out as he had predicted. The obituary memoirs of the two are -printed close together in the Astronomical Society’s “Monthly Notices.” -After a prolonged decline of strength, Sir John Herschel died at -Collingwood, in his seventy-ninth year, May 5th, 1871, his intellect -remaining unclouded to the last. He was buried in Westminster Abbey, -near the grave of Newton. The words engraven above his resting-place, -“Coelis exploratis, hic prope Newtonum requiescit,” tell what he did, -and what he deserved. - -His death created an universal sense of sorrow and of loss. He left -vacant a place which could never be filled. His powers, his qualities, -and his opportunities made a combination impossible to be reproduced. -His genius showed curious diversities from his father’s. He lacked -his profound absorption, his penetrating insight, his unaccountable -intuitions. A tendency to discursiveness, happily kept in check -by strength of will and devotion to an elevated purpose, replaced -in him his father’s enraptured concentration. On the other hand, -his appreciative instinct for the recondite beauty of mathematical -conceptions was wanting to his father. William Herschel possessed fine -mathematical abilities; but he cultivated them no further than was -necessary for the execution of his designs; and elementary geometry -served his turn. But Sir John might have taken primary rank as a pure -mathematician. Possibly his inventive faculty would have developed -in that line more strongly than in any other. The grasp of his mind -was indeed so wide that many possibilities of greatness were open -to him. That he chose rightly the one to make effective, no one -can doubt. The neglect on his part of astronomy would have been a -scientific delinquency. His splendid patrimony of telescopic results -and facilities was inalienable. It was a talent entrusted to him, -which he had not the right to bury in the ground. He laboured with it -instead to the last farthing. Not for his own glory. He aspired only -to fill up, for the honour of his father’s name, the large measure of -his achievements. In doing so he performed an unparalleled feat. He -swept from pole to pole the entire surface of the hollow sphere of the -sky. It is unlikely to be repeated. The days of celestial pioneering -are past. Nothing on the scale of a general survey will in future -be undertaken except with photographic help. The use of the direct -telescopic method tends to become more and more restricted. This is -a loss as well as a gain. A _hortus siccus_ is to a blooming garden -very much what a collection of photographs is to the luminous flowers -of the sky. They are depicted more completely, more significantly, -more conveniently for purposes of investigation, than they can be -seen; but the splendour of them is gone. Their direct contemplation -has an elevating effect upon the mind, which indirect study, however -diligent and instructive, is incapable of producing. The sublimity of -the visions drawn from the abyss of space cannot be reasoned about. It -strikes home to the spectator’s inner consciousness without waiting for -the approval of his understanding. Thus to Herschel, no less expressly -than to the Psalmist three thousand years earlier, “the heavens told -the glory of God.” He lived at his telescope a life apart, full of -incommunicable experiences. - -“To Herschel,” as Mr. Proctor expressed it, “astronomy was not a -matter of right ascension and declination; of poising, clamping, and -reading-off; of cataloguing and correcting.” “It was his peculiar -privilege,” Dean Stanley remarked in his funeral sermon, “to combine -with those more special studies such a width of view and such a power -of expression as to make him an interpreter, a poet of science, even -beyond his immediate sphere.” Hence the popularity of his books, and -the favoured place he occupied in public esteem. - -His character was of a more delicate fibre than his father’s. It was -also, by necessary consequence, less robust. Sir William Herschel -surmounted adversity. Sir John would have endured it, had his lot been -so appointed. But it never came his way. He was one of those rarest of -rare individuals-- - - “Whose even thread the Fates spin round and full, - Out of their choicest and their whitest wool.” - -His life was a tissue of felicities. For him there was no weary -waiting, no heart-sickening disappointment, no vicissitudes of -fortune, no mental or moral tempests. Success attended each one of -his efforts; he could look back without regret; he could look forward -with confident hope; his family relations brought him unalloyed -happiness. He suffered, indeed, one bereavement in the untimely death -of his daughter, Mrs. Marshall, the wife of a nephew of Dr. Whewell; -but Christian resignation sweetened his sorrow. His religion was -unpretending and efficacious. No duty was left by him unfulfilled; and -he wore, from youth to age, “the white flower of a blameless life.” -A discriminating onlooker said of him, that his existence “was full -of the serenity of the sage and the docile innocence of a child.” -He was retiring almost to a fault, careless of applause, candid -in accepting criticism. Although habitually indulgent, he was no -flatterer, “Anyone,” Mr. Proctor said, “who objected to be set right -when in error, might well be disposed to regard Sir John Herschel as -a merciless correspondent, notwithstanding the calm courtesy of his -remarks. He set truth in the first place, and by comparison with her, -neither his own opinions, nor those of others, were permitted to have -any weight whatever.” Beginners invariably met with his sympathy and -encouragement. He felt for difficulties which he himself had never -experienced. - -Being thus constituted, he could not but inspire affection. The French -physicist, Biot, when asked by Dr. Pritchard, after the death of -Laplace, who, in his opinion, was his worthiest successor, replied, -“If I did not love him so much, I should unhesitatingly say, John -Herschel.” His own attachments were warm and constant; and the few -scientific controversies in which he engaged, were carried on with his -habitual gentleness and urbanity. - -Herschel left eight daughters and three sons, of whom the eldest, Sir -William James Herschel, succeeded him in the baronetcy, while the -second, Professor Alexander Stewart Herschel, has earned celebrity -by his meteoric researches. The election of the third, Colonel John -Herschel, to a Fellowship of the Royal Society, in recognition of his -spectroscopic examination of southern nebulæ, threw a gleam of joy over -his father’s deathbed. Lady Herschel survived her husband upwards of -thirteen years. - -The learned societies of Europe vied with each other in enrolling -the name of Sir John Herschel; and he was nominated, in 1855, on the -death of Gauss, one of the eight foreign members of the French Academy -of Science. As we have seen, he received the Copley Medal from the -Royal Society twice, their Royal Medal thrice, and from the Royal -Astronomical Society, two Gold Medals and a testimonial. Compliments -and homage, however, left him as they found him--quiet, intent, and -unobtrusive. - -Several portraits of him are in existence. One was executed in oils -by Pickersgill for St. John’s College, Cambridge, at a comparatively -early period of his life. It is here (page 142) reproduced from an -admirable engraving. His later aspect is finely represented in a -painting by his eldest daughter, Lady Gordon. The eyes in it are -sunken, though brilliant; the shape of the head is concealed by a -mane of grey hair. There is about it something of leonine grandeur, -disjointed from leonine fierceness. It perpetuates, indeed, the -countenance of a man replete with human tenderness. - - - - -CHAPTER X. - -WRITINGS AND EXPERIMENTAL INVESTIGATIONS. - - -Could the whole of Sir John Herschel’s astronomical career be -obliterated, and the whole of his contributions to pure mathematics be -forgotten, he would still merit celebrity as a physicist. Experimental -optics, above all, engaged his attention. “Light,” he himself said, -“was his first love,” and he was never wholly forgetful of it. In 1830 -he described himself as “forcibly drawn aside from his optical studies” -by the claims of nebulæ and double stars. How strong he felt those -claims to be, can best be understood by considering the firmness with -which he averted his mind, out of regard to them, from the intricate -and bewitching subject of his early devotion. - -“I understand from Peacock,” Dr. Whewell wrote to him, June 19, 1818, -“that you are untwisting light like whipcord, examining every ray that -passes within half a mile, and putting the awful question, ‘Polarised, -or not polarised?’ to thousands that were never before suspected of any -intention but that of moving in a straight line.” These interrogatories -brought out a remarkable diversity in the action upon light of quartz, -and other similar substances, corresponding with the two different -modes of crystallisation belonging to each of them. Here, in Lord -Kelvin’s phrase, is “one of the most notable meeting-places between -natural history and natural philosophy.” - -The nascent science of spectrum analysis was materially promoted by -Herschel. He noticed in 1819 the distinctive light-absorbing qualities -of coloured media, studied the spectra of various flames, adverted -to the definiteness and individuality of the bright lines composing -them, and recommended their employment for purposes of chemical -identification. - -A year later, he developed and modified Brewster’s explanation of the -colours of mother-of-pearl. They do not, like the iridescence of a -fly’s wing, result from the interference of waves of light reflected -from two closely adjacent surfaces, but from interference brought about -by the finely striated texture of the shell’s surface, and a cast of -the rainbow-tinted surface in black sealing-wax will display the same -sheen of colour as the original. Herschel detected, however, a second -more closely striated structure which cannot be impressed upon plastic -matter. - -Up to this time he accepted unreservedly the emission theory of -light. But a candid study of Young’s and Fresnel’s writings produced -a fundamental change in his opinions; and in an article on “Light,” -written for the “Encyclopædia Metropolitana” in 1827, he expounded -the undulatory theory with all the ardour of a neophyte. He brought -thereby one of the grandest generalisations of science into universal -currency, and enforced its acceptance by the cogency of his -arguments, the logical order of his method, and the lucidity of his -style. The treatise was translated into French by Quetelet; and no -reader, Professor Pritchard remarked, “could escape the charm of the -half-suppressed enthusiasm which carried him along.” - -Whewell ranked him “among the _very_ small number of those who, in the -singularly splendid and striking researches of physical optics, had -both added important experimental laws to those previously known, and -weighed the relations of these discoveries to the refined and recondite -theory towards which they seemed to point.” He contributed to the -same Encyclopædia scarcely less brilliant essays on Heat, Sound, and -Physical Astronomy. - -“Do not observe too much in cold weather,” Miss Herschel advised her -nephew, in anticipation of the winter of 1831–2; “write rather books to -make folks stare at your profound knowledge.” - -He followed the positive part of her counsel. Indeed, his “Preliminary -Discourse on the Study of Natural Philosophy” had made its appearance -in the previous year, as the introductory volume to Lardner’s “Cabinet -Cyclopædia.” It was greeted with a chorus of approbation. Gauss -reviewed it in the _Gelehrte Anzeigen_, Whewell in the _Quarterly -Review_. Translated into French, German, and Italian, it delighted -“all sorts and conditions” of readers with the justice and breadth of -the views set forth in it agreeably, easily, and without pretension -to superiority. The book included a survey of the actual state -of scientific knowledge, and a philosophy of its augmentation. -Students derived from it, Gauss remarked, both information as to how -accepted results had been obtained, and guidance for their personal -investigations. Herschel was exceptionally qualified, Whewell wrote, -“to expound the rules and doctrines of that method of research to which -modern science has owed its long-continued, steady advance, and present -flourishing condition.” He had the knowledge, without the narrowness, -of a specialist in almost every department of experimental physics. -“With singular alacrity,” he came to the front wherever there seemed a -chance of pushing back the barriers of ignorance. A disciple of Bacon, -he had the advantage over his master of being habitually conversant -with the practical working of inductive methods. The treatise was -styled by Whewell “an admirable comment on the ‘Novum Organum.’” One, -however, possesses the indefinable quality of _greatness_; it stands -out from the centuries a solid structure, clothed with visionary -magnificence; the other is elegant, attractive, wise, acute, even -profound, but not in any degree, or from any point of view, _great_. - -It was followed, in 1833, by “A Treatise on Astronomy,” published in -the same series. An “Edinburgh Reviewer” (doubtless Brougham once more) -perused it with regret. “The proper position of Sir John Herschel” he -considered to be “at the head of those who are nobly, though it may -be silently and without notice, endeavouring to extend the present -limits of human knowledge,” rather than among “the ranks of those whose -office it is to herald the triumphs of science, and point out its -treasures and results to the admiration of the vulgar.” This ostensibly -flattering estimate was made the basis for an imputation of vanity. The -inducements, according to the critic, were strong “to descend from the -airy summits of abstract science to the level at which the great body -of the reading public can appreciate and applaud. Philosophers, like -other writers, naturally wish to be read, and to have reputation; and -reputation, as was remarked by d’Alembert, depends more upon the number -than the merit of those who praise.” Sir John Herschel would have been -better employed in pursuing the track of original discoveries, leaving -new truths to “find their way to the drawing-room as best they might.” -The whole tenour of his life refuted these insinuations. - -The “Treatise on Astronomy” was enlarged in 1849 into the deservedly -famous “Outlines of Astronomy.” Twelve editions of this book were -published, the last in 1873; it was translated into Chinese and Arabic, -as well as into most European languages, including Russian; it made a -profound and lasting impression upon the public mind. No science has -perhaps ever received so masterly a general interpretation. Methodical -in plan, inspiriting in execution, it demands readers willing to share -some part of the pains, for the sake of partaking in the high pleasures -of the writer. For it is popular in the sense of eschewing mathematical -formulæ, not in the sense of evading difficulties. - -The work fittest to be set by its side is the “Exposition du Système -du Monde.” But Laplace restricted his view to the sun’s domain, while -Herschel excluded from his no part of the sidereal universe. Laplace -was, besides, a geometer in the first, an astronomer only in the second -place. The movements of the heavenly bodies interested him because -they afforded opportunities for analytical triumphs. Their intricacy -notwithstanding, he was elated to find that they could not baffle his -ingenuity in constructing formulæ to correspond. Their balance, their -harmony, their obedience to a single and simple law, gratified the -orderly instincts of his powerful yet frigid mind. Where he could not -explain, however, he did not admire. Mystery had no attraction for -him. Knowledge, to _be_ knowledge in his eyes, should have definite, -clear-cut outlines. His scheme of the universe was like the map of the -world laid down by Hecatæus, neatly finished off with a circumfluent -ocean-stream; it included no intimations of a _beyond_. Herschel’s, on -the contrary, might be compared to the map of Herodotus, in which some -details were filled in, while the external boundary had been abolished. -The most essential part of the progress made in the interval consisted -in leaving verge and scope for the unknown. Next to nothing remained -to be learned of the heavens, as they presented themselves to the -author of the “Mécanique Céleste”; while Herschel saw everywhere only -beginnings, possibilities of discovery, and dim prospects of “ultimate -attainments,” as to the realisation of which “it would be unwise to be -sanguine, and unphilosophical to despair” (Playfair). At the head of -very many of his chapters he might, without presumption, have written: -“Quorum pars magna fui.” They gave largely the results of his personal -investigations, and were vivified by immediate acquaintanceship -with the objects described. Hence the unsought picturesqueness of -his descriptive epithets, and the sublimity of trains of thought -communicated to him direct from the unveiled heavens. - -Herschel invented in 1825, jointly with Babbage, the “astatic,” or -neutralised magnetic needle--a little instrument which was no sooner -available than it was found to be indispensable. “Nihil tetigit -quod non ornavit.” And many and various were the things touched by -his versatile genius. He had a narrow escape of becoming for life a -chemist. At the very outset of his career he applied for the vacant -chair of that science at Cambridge; but was left, as he himself -humorously expressed it, “in a glorious minority of one.” The chemical -inquiries, nevertheless, which he carried on at Slough brought to -his notice one set of relations of no trifling importance. This was -the solvent effect upon salts of silver of the hyposulphites of soda, -potash, etc. The discovery was turned to account by himself in 1840 -for the “fixing” of photographic images. It secured the future of the -embryo art. By the agency of hyposulphite of soda in washing away the -unaffected chloride of silver, while leaving untouched the parts of the -deposit decomposed and darkened by exposure, permanent light-pictures, -capable of indefinite multiplication, were at length secured. - -On March 14th, 1839, unaware that he had been anticipated by Fox -Talbot, Herschel presented to the Royal Society twenty-three prints -made by the sensitised paper process. A memoir communicated in 1840 -was full of suggestive novelties. In it he described experiments on -“the chemical analysis of the solar spectrum,” pointing out that the -character and amount of the action exercised by the various rays -depend mainly upon the nature of the substance acted upon. He made -a start, too, with spectral photography, and his detection of the -“lavender-grey” effect to the eye of the ultra-violet section might -be said to have added a new note to the prismatic gamut. In the -opposite, or infra-red end, by simply letting the solar spectrum fall -upon a strip of paper moistened with alcohol, he detected, through the -different rates of drying where they fell, some of the “cold bands,” -by which the invisible heat-rays are furrowed. The photo-spectroscopic -apparatus devised for the purpose of these researches formed part -of the Loan Collection of Scientific Instruments exhibited at South -Kensington in 1876. - -Still more essential was the improvement of substituting for paper, -glass plates spread with a sensitive film. A photograph of the old -forty-foot telescope, taken by this method in 1839, and preserved in -the South Kensington Museum, is of unrivalled antiquarian value as -regards the history of photography. The terms “positive” and “negative” -received in this remarkable paper their now familiar photographic -meaning. Its merits were acknowledged in 1840 by the award of a Royal -Medal. - -Sir John Herschel would, doubtless, at that time have set aside as -a chimera the notion that the art he was engaged in promoting was -destined, in large measure, to supersede visual methods in astronomy; -that the great telescopes of the future would find their most useful -employment in concentrating the rays of celestial objects upon -sensitive plates. He soon perceived, however, the importance of -photography as an adjunct to direct observation, and recommended, -in 1847, the automatic self-registration of sun-spots. This -hint--emphasised in 1848--was acted upon in 1858, when the regular -collection of documentary evidence as to the sun’s condition was begun -at Kew with De la Rue’s “photoheliograph.” - -In 1845 he published the first effective investigation of -“fluorescence,” called by him “epipolic,” or superficial, “dispersion.” -This curious phenomenon consists in the illumination to the eye of -certain substances, such as sulphate of quinine and canary glass, -under the play of _invisible_ light. Sir George Stokes showed in 1852 -that the impinging rays have their undulations actually lengthened by -the action of such kinds of matter, so as to become degraded in the -spectrum, and thus brought within the range of vision. - -The Herschelian theory of the sun was adopted, and long retained by -Sir John. He believed in a cool, solid interior globe sheltered by -a succession of aërial envelopes, rent, locally and temporarily, -by tornadoes of fire. The presence of inhabitants on the globe so -circumstanced was credible to him, although he abstained from dwelling -upon the advantages of their state. He carefully followed, however, the -progress of solar science, and in 1864 explained his altered views in -the _Quarterly Journal of Science_. He now regarded the sun as a wholly -gaseous mass--a conclusion in which he was anticipated only by Father -Secchi. He added that it must be largely composed of matter kept in an -intermediate condition between liquid and vaporous by “high temperature -and enormous pressure.” The spot-period, he suggested, might be that of -a revolving meteoric ring with condensations. - -He was vividly interested in the “willow-leaf” controversy, raised in -1862 by Nasmyth’s misinterpreted observations. The objects seen were -simply Sir William Herschel’s “nodules”--the luminous elements of the -sun, held by Sir John in 1867 “to be permanently solid matter, having -that sort of fibrous or filamentous structure which fits them, when -juxtaposed by drifting about, and jostling one against another, to -collect in flocks as _flue_ does in a room.” He concluded with the -remarkable assertion that the sun has no real surface, “the density -diminishing from that below the photosphere to _nil_ in the higher -regions, where the pressure is _nil_.” - -Herschel’s “Cape Observations” stands alone in astronomical literature -for the wide and permanent interest of its contents. They are -exceedingly various. Chapters on Halley’s Comet, on Sun-spots, the -Satellites of Saturn, Astrometry, the Constitution of the Southern -Galaxy, are associated with discussions on the nature and distribution -of nebulæ, with monographs of two, and incidental notes on many of -these enigmatical objects. The volume is illustrated with over sixty -beautiful steel engravings of nebulæ and clusters, of sun-spots, and of -the comet. - -The speculations it includes regarding the nature of nebulæ, deserve -even now to be remembered. Sir John was, at the outset, an unwavering -adherent of the theory developed by his father in 1811. They were -composed, he held in 1825, of a “self-luminous; or phosphorescent -material substance, in a highly dilated or gaseous state, but gradually -subsiding, by the mutual gravitation of its molecules, into stars -and sidereal systems.” His personal experience, however, ran counter -to this view. In 1833 he had become convinced that a nebula is, in -general, “nothing more than a cluster of discrete stars.” - -The successful resolution into stars, with the great Parsonstown -specula, of many nebulæ until then called irresolvable, carried him -still further in the same direction. To him, as to other thinkers, -the presence in space of a self-luminous cosmic fluid became more -than doubtful. In his Presidential Address to the British Association -in 1845, he dwelt with enthusiasm on the completion of the Rosse -reflector--“an achievement of such magnitude, that I want words to -express my admiration of it.” He regarded “as one of the grand fields -open for discovery with such an instrument, those marvellous and -mysterious bodies, or systems of bodies, the nebulæ.” Their frequent -resolution, actual or indicated, with increased optical power, led -him to attribute recalcitrance in this respect to the smallness and -closeness of the stars of which they consist; he held them, in short, -to be “optically, and not physically, nebulous.” - -A new consideration was thus introduced into discussions on nebulæ. The -whole burthen of accounting for their varieties in telescopic aspect -need no longer be thrown upon differences of remoteness; diversities -in the size and closeness of nebular _molecules_ would answer the same -purpose. So that pulverulent agglomerations, it was thought, might pass -by insensible gradations into collections of truly sun-like bodies. All -distinction between nebulæ and clusters was then abolished, the members -of both classes consisting, like the sun’s photosphere, of shining -granules, supported in an obscure medium, varying in real magnitude -from _floccules_ to great globes, while each vast compound body rotated -_en masse_ on an axis. Whatever the merits of this scheme, it at least -harmonises with the now prevalent opinion that nebulæ and clusters -belong to one unbroken cosmical series. “They are divided,” Mr. Cowper -Ranyard wrote in 1893, “by no hard and fast line. The larger nebulæ may -be described as groups of stars surrounded by bright nebulosity, and -star-clusters as groups of stars surrounded by faint nebulosity.” - -Herschel’s assimilation of nebulæ to clusters was not meant to apply -to “those extraordinary objects resembling the wisps and curls of a -cirrous cloud,” which confront the astronomer in Orion, Argo, and -elsewhere. “The wildest imagination,” he said, “can conceive nothing -more capricious than their forms. With their resolution,” he averred, -“and that of elliptic nebulæ, the idea of a nebulous matter, in the -nature of a shining fluid or condensible gas, would cease to derive -any support from observation.” He, in fact, discarded it absolutely on -the deceptive analysis into stars at Parsonstown and Harvard College -of the Orion and Andromeda nebulæ. The discredited hypothesis was -nevertheless triumphantly reinstated by Dr. Huggins’s spectroscopic -observations in 1864. - -One-third of the whole nebular contents of the heavens Herschel found -to be collected into a broad, irregular patch, the central point of -which in Virgo coincides almost precisely with the northern pole of -the Milky Way. He compared it to a canopy surmounting the galactic -zone. In the other hemisphere the arrangement, although less distinctly -characterised, is on the same general plan. Plainly, then, nebular -distribution has an opposite correspondence with stellar distribution, -and the two partial systems are complementary one to another, Herschel, -however, contented himself with the somewhat ambiguous statement that -“the nebulous system is distinct from the sidereal, though involving -and, to a certain extent, intermixed with it.” - -His verdict as to the ground-plan of the sidereal edifice might be -summed up in the phrase, “Not a stratum, but an annulus,” our own -situation being in a relatively vacant interior space. Hence, the sun -belongs, not to the Milky Way proper--as it should on the stratum -theory--but to the system of which the Milky Way forms part. This -conclusion was in itself a distinct advance towards the solution of an -exorbitantly difficult problem. The grand question as to the remoteness -of the star-clouds in that gleaming sky-girdle was definitely raised -by it; and the question is not, in the nature of things, unanswerable. -Herschel’s annulus was not a neat structure with a cylindrical -section, but “a flat ring, or some other re-entering form of immense -and irregular breadth and thickness.” It is cloven over one-third of -its circumference; it is interrupted by huge chasms; it is bent, and -shattered and broken, and probably set with tentacular appendages, -giving rise, by their foreshortening, to very complex visual effects. -All of which modifying circumstances Herschel implicitly recognised. -He was the first to gather any direct intimations of the existence -of that “solar cluster” which, guessed at by the elder Herschel, has -of late assumed a sort of elusive reality. A zone of bright stars, -including those of Orion, Canis Major, the Ship, the Cross, and the -Centaur, struck him at once as a conspicuous feature in the scenery of -the southern heavens. Its aspect led him to “suspect that our nearest -neighbours in the sidereal system form part of a subordinate sheet, or -stratum,” inclined at an angle of twenty degrees to the plane of the -Milky Way. To Dr. Gould at Cordoba, in 1879, “few celestial phenomena” -appeared “more palpable” than this projected star-belt; and, since -it traces out a great circle on the sphere, the sun must be placed -within it, and pretty accurately in its plane; yet the difficulty -of associating it intimately with our particular star seems all but -insurmountable. - -Herschel’s minor and occasional writings were neither few nor -unimportant. He contributed articles on “Isoperimetrical Problems” -and “Mathematics” to Brewster’s _Edinburgh Cyclopædia_, and on -“Meteorology,” “Physical Geography,” and “The Telescope,” to the -eighth edition of the _Encyclopædia Britannica_. These last were -printed separately as well. He edited in 1849 the Admiralty “Manual -of Scientific Inquiry,” and criticised in the _Edinburgh_ and -_Quarterly Reviews_ Mrs. Somerville’s “Mechanism of the Heavens,” -Whewell’s “History of the Inductive Sciences,” Humboldt’s “Kosmos,” -and Quetelet’s “Theory of Probabilities.” His addresses as President -of the Royal Astronomical Society were models of their kind, and the -same might be said of his memoirs of Baily and Bessel in the “Monthly -Notices.” Most of them were collected in 1857, with his review -articles, into a volume of “Essays;” and his attractive “Familiar -Lectures on Scientific Subjects,” published in 1867, gave permanence to -some popular discourses delivered in the school-house of Hawkhurst, as -well as to articles from _Good Words_ on Light and other subjects. No -less than 152 papers by him are included in scientific repertories. - -He had a considerable faculty for translating poetry, and its exercise -made one of his favourite recreations. Having adopted the literal -theory of the art, he kept strictly to the original metres, and thus -fettered, got over the ground with more grace and ease than might have -been expected. His first attempt with English hexameters was in a -version of Schiller’s “Walk,” privately printed in 1842. He had come -to love the poem through its association in his mind with a favourite -stroll up the side of Table Mountain; and a translation of it in the -_Edinburgh Review_ leaving, as he thought, something to be desired, -he tried his hand, and distributed the result “among his friends as -his Christmas sugar plum.” The various acknowledgments made an amusing -collection. One lady said that she “found it difficult to get into the -_step_ of the _Walk_.” Another correspondent declared that the _Walk_ -had got into a _Run_ through ceaseless borrowing. A third qualified his -encomium upon the ideas by adding, “To the _verse_ I am _averse_.” -Joanna Baillie, however, and her sister were delighted with both the -substance and form of the poem, and it was included among Whewell’s -“English Hexameter Translations” in 1847. - -His success encouraged him, after twenty years, to undertake an -indefinitely more difficult task. Pope’s Iliad he described happily as -“a magnificent adumbration” of the original; but he aimed rather at -producing a “fac-simile,” in - - “Hexameters no worse than daring Germany gave us.” - -His version should come as near as he could bring it to a photograph -of a grand piece of architecture; and as a measure of its fidelity, he -printed in italics all the words _not_ in the text. Whewell remarked -that it was “curious to see how few he had managed to make them,” and -preferred his translation to any other with which he was acquainted. -But English hexameters were a hobby of the Master of Trinity, who -accordingly viewed with partiality what Tennyson called the “burlesque -barbarous experiment” of thus lamely rendering “the strong-wing’d music -of Homer.” - -De Morgan, too, was one of the “averse.” “Many thanks for the -hexameters,” he wrote, on receiving an instalment of the Collingwood -Iliad; “they are as good as they can be, but all the logic in the -world does not make me feel them to be English metre, and they give -satisfaction only by reminding one of the Greek: just as, mark you, -a flute-player--which I have been these forty-five years--only plays -Haydn and Mozart because he has the assistance of the orchestral -accompaniment which arises in his head with the melody. The hexameter, -it is clear, does not fix itself in the popular mind. The popular mind -knows neither quantity nor accent, but that which is to last bites its -own way in, without any effort.” - -Yet Herschel’s translation is not without merit. It is disfigured -neither by affectation nor by magniloquence, and it catches here and -there something of the greatness of the unapproached original. Let us -take two specimens; this from the “Shield of Achilles”:-- - - “There he depicted the earth, and the canopied sky, and the ocean; - There the unwearied sun, and the full-orb’d moon in their courses. - All the configured stars, which 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 its course regarding Orion; - Sole of the starry train which refuses to bathe in the Ocean.” - -The next likewise appeals to the astronomer. It is the famous simile -from the end of the Eighth Book:-- - - “As when around the glowing moon resplendent in ether, - Shines forth the heavenly host, and the air reposes in stillness; - Gleams every pointed rock, stands forth each buttress in prospect; - Shimmers each woodland vale; and from realms of unspeakable glory - Op’ning, the stars are revealed; and the heart of the shepherd - rejoices. - Such, and so many the fires, by the Trojans kindled, illumined - Eddying Xanthus’ stream, and the ships, and the walls of the city.” - -Sir John Herschel corresponded with Mr. Proctor, during the last two -years of his life, on the subject of sidereal construction; and his -replies to the arguments put before him show that his mind retained, -even then, its openness and flexibility. He had none of the contempt -for speculative excursions which sometimes walls up the thinking-powers -of observers. “In the midst of so much darkness,” he held that “we -ought to open our eyes as wide as possible to any glimpse of light, -and utilise whatever twilight may be accorded us, to make out, though -but indistinctly, the forms that surround us.” “_Hypotheses fingo_ in -this style of our knowledge,” he went on, “is quite as good a motto -as Newton’s _non fingo_--provided always they be not hypotheses as to -modes of physical action for which experience gives no warrant.” And -again: “We may--indeed, must--form theories as we go along; and they -serve as guides for inquiry, or suggestions of things to inquire; but -as yet we must hold them rather loosely, and for many years to come -keep looking out for side-lights.” - -These were his last words on the philosophy of discovery: and they -constituted his last advice to scientific inquirers. But, good as -were his precepts, his example was better. There was no discrepancy -between his work and his thought. Both combined to inculcate aloofness -from prejudice, readiness of conviction in unequivocal circumstances, -suspension of judgment in dubious ones, and in all, candour, sobriety, -and an earnest seeking for truth. - - - - -INDEX. - - - Actinometer, J. Herschel’s, 152, 179, 180 - - Adams, J. C., at Collingwood, 188 - - Ages of heavenly bodies, 68, 94, 170 - - Alexander, the Czar, 49 - - Amici, of Modena, 148, 150 - - Apertures, method of, 61, 63 - - Apex, solar, 78, 80 - - Archbishop of Canterbury, and George III., 38 - - Argelander, 80, 106 - - Asteroids, 46, 90–1, 95, 100 - - Astrometer, J. Herschel’s, 177 - - Astronomical Society, 49, 152, 188 - - Aubert, Alexander, 16, 101, 124 - - - Babbage, companionship with J. Herschel, 143–4, 149, 152; - astatic needle, 208 - - Bailey, S. I., 169, 170 - - Baily, Francis, 164, 185, 186, 187 - - Barnard, diameters of asteroids, 91; - nebulosities, 110–11; - photographs of Milky Way, 174 - - Bates, Joah, anecdote of W. Herschel, 12 - - Bath, centre of fashion, 12; - Herschel’s residences there, 17, 26, 47 - - Beckedorff, Mrs., 126, 127, 160; - Miss, 138 - - Bessel, solar movement, 80; - estimate of W. Herschel, 109; - Halley’s comet, 177; - at Collingwood, 187; - memoir of, 216 - - Biot, estimate of J. Herschel, 201 - - Bonaparte, Lucien, 33, 44 - - Bonaparte, Napoleon, Herschel’s interview with, 47 - - Bradley, observation of Castor, 76 - - Brougham, Lord, 53, 88, 90, 207 - - Burney, Dr., notices of W. Herschel, 12, 44, 45–6; - walk through forty-foot, 38; - notices of Caroline and J. Herschel, 125, 142 - - Burney, Miss, meetings with W. Herschel, 38–9; - with Mrs. and Miss Herschel, 44, 124, 125, 127 - - Burnham, double stars, 103; - planetary nebulæ, 155 - - - Campbell, Thomas, admiration for W. Herschel, 47–8; - notice of his son, 145 - - Cavendish, anecdote of, 100 - - Clay Hall, 36 - - Climate, changes of, 82 - - Comet, of October 1806, 48; - of 1811, 94; - Encke’s, 124, 175; - of 1819, 128–9; - Biela’s, 153; - Halley’s, 175–6, 180, 211 - - Comets, decay of, 94; - Miss Herschel’s, 124, 125 - - Common, Dr., five-foot reflector, 99 - - Construction of the Heavens, 53, 60, 113–114, 214–15 - - - Dante and the “Divina Commedia,” 15 - - Datchet, house at, 32, 36 - - Dawes, sun-spot nuclei, 83 - - De la Rue, photoheliograph, 210 - - De Morgan, letter to Captain Smyth, 188–9; - Herschel and the coinage, 191; - friendship with, 197; - dislike to hexameters, 217 - - Dreyer, Catalogue of Nebulæ, 192 - - - Easton, Milky Way structure, 106 - - Edgeworth, Miss, at Slough and Collingwood, 192–3 - - - Feldhausen, 163, 180, 181 - - Flamsteed, British Catalogue, 80, 123, 126 - - - Galileo, double-star method of parallaxes, 55 - - Gauss, 151, 201, 205 - - George III., patronage of Herschel, 10, 24, 28–9, 30, 32, 33; - taste for astronomy, 30, 47; - walk through great telescope, 38 - - Gill, Dr., Herschel’s micrometers, 103; - photographic catalogue, 106; - photographs of Argo nebula, 167; - of Omega Centauri, 169 - - Gordon, Lady, portrait of Sir J. Herschel, 202 - - Gould, Dr., solar cluster, 107, 215 - - Grahame, James, 149 - - Gravitation, extension of to stellar systems, 77, 148 - - Gregorian reflectors, 20, 29 - - Griesbach, Mrs., 10, 116; - her sons, 10, 28, 29 - - - Halley, list of nebulæ, 19; - stellar motions, 77 - - Hamilton, Sir W. R., communications with J. Herschel, 146, 152, - 158, 173, 188; - speech by, 182; - at Collingwood, 193; - quaternions, 194–5 - - Haydn, visit to Slough, 44 - - Heat-rays in solar spectrum, 95–6 - - Herschel, Alexander, assisted his brother, 13, 21, 27, 120; - accompanied him to Göttingen, 37; - supported by him, 51; - care for his sister, 118 - - Herschel, Professor Alexander, meteoric researches, 201 - - Herschel, Caroline, fetched to Bath, 15, 118; - help in speculum making, 15, 20, 124; - a singer, 21, 117, 119; - remarks, 25, 27, 34, 49; - letters from W. Herschel, 28, 29, 30, 129; - household cares, 32, 118, 121; - reminiscences, 35, 36, 37, 39, 48, 50, 68; - annuity, 51, 131; - birth and childhood, 115–16; - education, 115, 118, 121; - visits to London, 121, 127; - discoveries of nebulæ, 122; - of comets, 124–5, 139; - her brother’s assistant, 122–3, 125; - catalogues nebulæ, 123, 132; - Index to Flamsteed’s observations, 126; - royal attentions, 126, 127, 133, 135, 139; - anxiety about her brother’s health, 128–9; - return to Hanover, 130–1; - Gold Medals bestowed on, 132, 138; - joy in her nephew’s career, 134–5, 159; - his visits, 135–36, 159; - Recollections and Journals, 137, 138; - death, 139; - personality, 139–41; - anecdotes of J. Herschel’s childhood, 142; - his letters to her, 151, 152, 153, 162–3, 164, 175, 176, 187; - her portrait, 196; - her advice to him, 205 - - Herschel, Dietrich, 20–1, 51, 127–8, 130, 131 - - Herschel, Sir John, dismantling of great telescope, 43; - catalogues of nebulæ, 132, 155, 191–2; - visits to Hanover, 135–6, 151, 159–60, 184; - nebular observations, 136, 153, 154–7, 165–7; - Cape Expedition, 135, 159–2, 181–2; - birth and childhood, 142; - university career, 143–5; - medals awarded to, 145, 148, 149, 157, 187, 201; - work on double stars, 134, 146–48, 157; - method for computing orbits, 148–9; - general catalogue, 192; - ascents of Monte Rosa and Etna, 149–50; - explorations in Auvergne, 152; - experiments on solar radiation, 151–2, 179; - visit to Ireland, 152; - cometary observations, 153, 175–6, 180, 189; - telescopes, 153, 158, 164, 183; - discovery of star in Orion-trapezium, 158; - marriage, 159; - Feldhausen, 163, 180–1; - Cape climate, 164; - Magellanic Clouds, 165–6; - Argo nebula, 167; - Eta Argûs, 168–9; - globular clusters, 169–71, 213; - star-gauging, 171–2; - comets, 175–6; - stellar photometry, 177; - solar theory, 178–9, 211; - Saturnian satellites, 180; - magnetic work, 184, 189, 208; - constellational reform, 185; - removal to Collingwood, 186; - Cape Results, 186–7, 211–12; - President Astronomical Society, 188; - Master of the Mint, 190–1; - guests at Collingwood, 188, 193, 195; - sonnet, 194; - family life, 195–6; - death, 197; - powers and character, 198–201; - books, 205–8; - photographic experiments, 209–10; - nature of nebulæ, 212–14; - solar cluster, 215; - poetical performances, 216–18; - philosophy of discovery, 219 - - Herschel, Colonel John, examination of nebular spectra, 201 - - Herschel, Isaac, 9, 21, 115, 116 - - Herschel, Jacob, 116, 117, 128 - - Herschel, Lady, the elder, 44, 50, 152, 160 - - Herschel, Lady, the younger, 159, 192, 194, 201 - - Herschel, Sir William, birth, 9; - musical career, 10–16, 21, 26, 121; - telescope, making, 14–15, 17, 19, 20, 22; - thirty-foot, 26–8, - seven-foot, 28–9; - for sale, 33; - forty-foot, 34, 37, 38, 41–3, 49, 50, 100, 137, 210; - twenty-foot, 35–6, 40, 50; - front-view telescopes, 40, 41, 102, 153; - space-penetrating power of, 61, 98; - reviews of the heavens, 19, 20, 26, 35, 36, 42, 46; - early papers, 22–3; - discovery of Uranus, 24–5, 120; - observations of double stars, 26, 49, 55–6, 75; - interviews with the king, 28–30; - royal astronomer, 30, 32–3; - mode of observing, 30, 122; - discovery of Uranian satellites, 40, 93, 153; - of Saturnian satellites, 41, 43, 92; - marriage, 44; - aversion to poetry, 45–6; - interview with Bonaparte, 47; - observations of comets, 48, 94, 128–9; - failure of health, 49–50, 128–9; - death and character, 51; - construction of the heavens, 53–4, 60, 114; - star distances, 54–5, 57, 60–1, 64, 75; - star-gauging, 57–8, 113; - nature of the Milky Way, 57–9, 62–3; - chasms in, 68; - method of apertures, 61; - catalogues of nebulæ, 64; - varieties, 65; - island universes, 66–7, 72; - development, 67–8; - nebulous fluid, 69–70; - condensation into stars, 71–2, 109; - nebular distribution, 73; - discovery of binary stars, 76–7, 147; - transport of the solar system, 77, 80, 108; - stellar photometry, 80–2, 174–5; - theory of the sun, 83–6, 211; - sun spots and weather, 87–8; - observations of Venus, 88; - of Mars, 89; - of the asteroids, 90; - of Saturn, 91; - law of satellite-rotation, 92; - lunar volcanoes, 93; - detection of infra-red heat-rays, 95–7; - use of high powers, 101–2; - micrometers, 103; - photometric enumeration, 106; - solar cluster, 107–8; - diffused nebulosities, 110–11; - a founder of sidereal astronomy, 112 - - Herschel, Sir William J., 49, 136, 183, 201 - - Huggins, Dr., spectra of nebulæ, 109, 214; - of stars, 113 - - Humboldt, 133, 138, 170, 184 - - Huygens, improvement of telescopes, 17 - - - Jacob, southern Milky Way, 172 - - Japetus, rotation of, 92 - - Jupiter, trade wind theory of, 91; - rotation of satellites, 93 - - - Kapteyn, solar cluster, 107 - - Knipping, Mrs., 137, 138 - - - Lacaille, southern nebulæ, 19 - - Langley, bolometer, 95; - atmospheric absorption, 152, 179 - - Laplace, 18, 47, 91, 201, 207 - - Lassell, Uranian satellites, 93; - reflectors, 99; - observation of Mimas, 180 - - Le Verrier, 187, 188 - - Lexell, orbit of Uranus, 24 - - - Maclear, Sir Thomas, 162, 168, 176, 181 - - Magellan, Von, accounts of William and Caroline Herschel, 40, 122 - - Magellanic clouds, 165–6 - - Magnitudes, stellar, 81, 104–5, 177 - - Mars, analogy with the earth, 89 - - Maskelyne, 25, 29, 76 - - Mayer, Christian, satellite-stars, 75 - - Mayer, Tobias, solar translation, 77, 78 - - Michell, revolving stars, 75; - solar group, 107 - - Micrometer, lamp, 24, 103; - wire, 56, 103 - - Milky Way, rifts in, 50, 67–8, 173, 175, 215; - structure, 57–59, 62, 173–4, 214–15; - spectral peculiarity, 105; - distance, 106, 173, 214; - splendour in southern hemisphere, 172; - photographic portrayal, 174–5 - - Miller, Dr., 11, 12 - - Mitchell, Miss, visit to Collingwood, 195–6 - - Monck, stellar spectroscopic distribution, 107 - - Moon, mountains of, 22, 23; - volcanoes, 93–4. - - - Nasmyth, opinion of J. Herschel, 196–7; - solar willow leaves, 211 - - Nebula, Orion, 15, 43, 65, 70, 71, 110, 111, 153, 167, 214; - Dumb-bell, 157; - Argo, 167; - Andromeda, 214 - - Nebulæ, catalogues, 19, 64, 123, 132, 191–2; - discoveries, 35, 64, 122, 165; - nature, 66, 212–4; - development, 67, 69, 109–10; - distribution, 73, 214 - - Nebulæ, annular, 65, 157, 165 - - Nebulæ, double, 72, 156 - - Nebulæ, planetary, 65, 67, 71; - spectrum, 109; - satellites to, 155; - colour, 165 - - Nebulæ, rifted, 157 - - Nebular theory, 71–2, 109 - - Newton, law of gravitation, 17, 77; - reflectors, 20, 23; - mode of investigation, 23, 206 - - - Olbers, origin of asteroids, 90; - comet of 1819, 129; - light extinction, 174; - visit from J. Herschel, 184 - - Orange, Prince of, enquiries at Slough, 39 - - - Papendick, Mrs., remarks on William and Caroline Herschel, 39, 44, 125 - - Peacock, Dean, 143, 194, 203 - - Photography, of stellar spectra, 104, 107; - of nebulæ, 110–11, 113, 166–7; - star charting by, 113, 172, 199; - of clusters, 169–70, 171; - of solar spectrum, 209; - of sun-spots, 210 - - Photometric enumeration, 60, 106, 107, 114; - catalogues, 80 - - Photometry, stellar, 81, 104, 177; - photographic, 105 - - Piazzi, visit to Slough, 39, 150 - - Pickering, E. C. and W. H., photographs of Orion nebula, 111 - - Pouillet, solar radiation, 179 - - Pritchard, Dr., 143, 192, 201, 204 - - Proctor, star-drift, 108; - estimate of Sir J. Herschel, 199, 200; - correspondence with, 218 - - - Ranyard, A. C., changes in nebulæ, 168; - clusters, 213 - - Roberts, Dr., photographs of nebulæ, 157, 165 - - Rosse reflector, 99, 212 - - Russell, H. C., photographs of Magellanic clouds, 166; - of Argo nebula, 167; - of Milky Way, 175 - - - Saturn, artificial, 30; - satellites, 41, 43, 91, 92, 180; - rings, 91–2 - - Savary, stellar orbits, 148, 149 - - Schröter, 34, 84, 88–9 - - Secchi, 113, 211 - - See, Dr., double nebulæ, 156 - - Sirius, brilliancy, 42, 168; - standard star, 58, 61, 63, 80 - - Slough, W. Herschel’s residence at, 36, 44; - birthplace of J. Herschel, 142 - - Sniadecki, stay at Slough, 39 - - Solar cluster, 107, 215 - - Solar radiation, 151–2, 179 - - Somerville, Mrs., 132 - - South, Sir James, 146, 147, 149 - - Spectrum analysis, 84, 204, 209 - - Spencer, unity of sidereal system, 166 - - Stanley, Dean, on J. Herschel, 199 - - Star-clusters, 49, 59, 63, 67, 72, 169–71, 213 - - Star-gauging, 57–8, 113, 171–2 - - Stars, binary, 72, 156; - discovery, 76–7, 147; - orbits, 147–9 - - Stars, double, observations of, 55–6, 103, 146–8, 157; - colours, 56, 112, 156; - nebular relations, 155 - - Stars, distribution of, 58–9, 60, 73, 81, 106, 171–2 - - Stars, movements of, 77, 107–8 - - Stars, nebulous, 69, 70, 71 - - Stars, spectra of, 83, 105 - - Stars, spectroscopic binary, 104 - - Stars, temporary, 66–7 - - Stars, variable, 23, 81–2, 168–9 - - Stokes, Sir G., fluorescence, 210 - - Stone, Herschel’s assistant, 180 - - Struve, W., 148, 158, 188 - - Sun, translation, 77–80, 108; - vicissitudes, 82, 87, 88; - constitution, 83–6, 178–9, 211 - - Sussex, Duke of, 158 - - - Telescopes, Improvement of, 17, 19, 20, 24–6, 33, 36, 98–100 - - - Uranus, discovery of, 24–5, 26, 120; - satellites, 40, 93, 153 - - - Watson, Sir W., 16, 22, 27, 30, 47, 124 - - Watt, James, 47 - - Whewell, Dr., unity of sidereal system, 76, 166; - friendship with J. Herschel, 145, 163, 191, 200; - tidal data, 181; - articles in Quarterly Review, 186, 205–6; - Geological Society, 189; - on optical enquiries, 203–4; - hexameters, 217 - - Wolf, Dr. Max, photographs of nebulæ, 111; - of Milky Way, 175 - - Wollaston, 145, 177 - - Worlds, inhabited, 85, 86, 89, 147. - - -PRINTED BY CASSELL & COMPANY, LIMITED, LA BELLE SAUVAGE PRINTING WORKS, -LONDON, E.C. - - - - -Transcriber’s Notes - - -Punctuation, hyphenation, and spelling were made consistent when a -predominant preference was found in the original book; otherwise they -were not changed. - -Simple typographical errors were corrected; unbalanced quotation -marks were remedied when the change was obvious, and otherwise left -unbalanced. - -Illustrations in this eBook have been positioned between paragraphs -and outside quotations. 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