MacTutor
The name of HERSCHEL, mentioned in this the sadder portion of our anniversary proceedings, calls forth one of the best and deepest of our emotions, veneration for the memory of an illustrious man and faithful friend departed to his rest; but not departed before the imperishable labours of a long life had been nobly accomplished. From ourselves this tribute of respect is especially due, inasmuch as from the earliest rise of our Society until now that it has passed its fiftieth year, John Herschel promoted and adorned its progress in all kindly offices and with a constant solicitude. With the single exception of his early friend Babbage, who survived him but a few months, he was the last of that list of admirable men who launched the Royal Astronomical Society on its career of eminent success and scientific usefulness. Happily their mantle has descended on successors still left to us, able and worthy to carry on the work which those men commenced so well. We have entered on the harvest of our fathers' labours, rejoicing in the not less successful efforts of their sons.
John Herschel was born at Slough, on March 7, 1792, in that house which his father's discoveries have rendered historical. A few traits of his boyhood, mentioned by himself in his maturer life, have been treasured up by those who were dear to him, and the record of some of them may satisfy a curiosity as pardonable as inevitable, which craves to learn through what early steps great men or great nations become illustrious. His home was singular, and singularly calculated to nurture into greatness any child born as John Herschel was, with natural gifts capable of wide development. At the head of the house there was the aged, observant, reticent philosopher; and rarely far away, was his devoted sister, Caroline Herschel, whose labours and whose fame are still cognisable as a beneficent satellite to the brighter light of her illustrious brother. It was in the companionship of these remarkable persons, and under the shadow of his father's wonderful telescope, that John Herschel passed his boyish years. He saw them, in silent but ceaseless industry, busied about things which had no apparent concern with the world outside the walls of that well-known house, but which, at a later period of his life, he, with an unrivalled eloquence, taught his countrymen to appreciate as foremost among those living influences which best satisfy and elevate the noblest instincts of our nature. What sort of intercourse passed between the father and the boy, may be gathered from an incident or two which he narrated as having impressed themselves permanently on the memory of his youth. He once asked his father what he thought was the oldest of all things. The father replied, after the Socratic method, by putting another question, "And what do you yourself suppose is the oldest of all things?" The boy was not successful in his answers, whereon the old astronomer took up a small stone from the garden-walk: "There, my child, there is the oldest of all the things that I certainly know." On another occasion his father is said to have asked the hoy, "What sort of things, do you think, are most alike?" The delicate, blue-eyed boy, after a short pause, replied, "The leaves of the same tree are most alike to each other." "Gather, then, a handful of leaves from that tree," rejoined the Philosopher, "and choose two that are alike." The boy failed; but he hid the lesson in his heart, and his thoughts were revealed after many days. These incidents may be trifles; nor should we record them here, had not John Herschel himself, though singularly reticent about his personal emotions, recorded them as having made a strong impression on his mind. Beyond all doubt, we can trace therein, first, that grasp and grouping of many things in one, implied in the stone as the oldest of things; and, secondly, that fine and subtle discrimination of each thing out of many like things, as forming the main features which characterised the habit of our venerated friend's philosophy.
In due time he was sent to Eton. It was close to his home; too close, indeed, for the jealous inspection of a mother's eye, for it was not long before she saw him maltreated by a stronger boy, and he was removed from the great school. Perhaps happily so, for the atmosphere of the public schools of that day was not suited for the nurture of a philosophical astronomer. Thus he was educated at home; and how successful that education was is written in the volumes and the manners of his life; for John Herschel became every way an accomplished man; he was a good and a fond scholar, an excellent modern linguist, a musician, and accomplished in the literature of the day. He always spoke affectionately of his tutor Mr. Rogers, but that gentleman does not appear to have been more successful in his attempts to impart a knowledge of geometry to his illustrious pupil than are the majority of the tutors of the present day; for John Herschel has been known to state that he learned Euclid accurately and diligently, but that "he knew no more of its real bearing and inten-tion than he knew of the man in the moon." This is a pity, but we have much reason to fear that this is a pitiably common result. Perhaps no one would be more amazed than the great Geometer of Alexandria himself, if he were to return to life and find that his books, written for mature philosophers, were put without note, comment, or preparation, into the hands of the boys of the nineteenth century, to flounder therein just as they may chance.
Be this as it may, Herschel was sent to Cambridge at the unusually early age of seventeen.
His University career would no doubt have been eminently successful to whatever college he might have been sent, but he must have found a great facility for the development of his natural bias in having been entered by his father at St. John's. That College was then, and has ever since been, conspicuous for the careful and judicious training and the generous encouragement of its younger members in every branch of academical learning, and we venture to say that in none was, or is, the Principia of Newton studied with greater intelligence or devotion. In Herschel's day, and for many subsequent years, this immortal work was presented to the students in the form of manu-scripts, in which the prescribed sections of the book were provided in an English dress. Herschel, however, made it his duty to read nearly the whole book in the original Latin. This is one instance out of many others, of that thoroughness of work which he displayed through life; it was the bent and genius of his mind; it was the happy tradition of his home. With such natural gifts developed by so able a training, it is no wonder that Herschel graduated as the Senior Wrangler of his year. Peacock, afterwards Dean of Ely, a man of rare ability, was the second on the list, followed by several others who became conspicuous in their day.
It is well known that great changes were imminent at Cambridge in the form of the study of mathematical learning at the time when Herschel was an undergraduate. From a variety of causes, not very easily understood, mathematical analysis had not made that advancement in England which had been so remarkable on the Continent ever since the death of Newton. The Cambridge professors and teachers acted as if they had a vested interest in the powerful geometry of the past; many of them were possessed of vast mental capacity, but they continued to encumber themselves with an old fluxional notation, and ponderous methods, which had long been discarded by the philosophers abroad. Waring at Cambridge and Lagrange at Turin were both born in the same year, 1736; both of them wrote – and wrote ably on the same subject, the Theory of Numerical Equations, yet the difference between the notations and even the methods of the two analysts, is something incredible to a person who has never taken the trouble of making the comparison. But it was not Cambridge alone which was in fault; a similar remark is applicable to the writings of Thomas Simpson in London and Euler at St. Petersburg. Yet the two Englishmen were probably endowed with natural genius comparable with those of their foreign compeers.
It was Woodhouse at Cambridge who first applied himself seriously and systematically to remove this stigma and this obstacle to all true scientific progress. He paved the way to ultimate success, not so much by his deeper and more controversial treatises, as by an elementary work on Trigonometry, which for the first time opened the door of the Continental forms of analysis, to the English student. This able and important, though elementary treatise, was published in the year when Herschel joined the University, and the influence which it had upon his mind is evidenced by the fact that the first contributions which he made, and that too during the years of his undergraduateship, to a scientific periodical of the day, were based on what he had read in Woodhouse's book. It was natural also that Herschel, even before his degree, should warmly espouse and effectually assist the cause in which his senior was so actively engaged.
One of Herschel's first works after his degree was an effort in the same direction, namely, to render the magnificent methods and results of analysis, which had so long been familiar to the minds of foreigners, accessible to the English student. With this view, and in conjunction with two of his university friends, he translated the best elementary treatise of that day on the Differential Calculus, adding, thereto, a valuable appendix on the cognate subject of Finite Differences from his own hands. Not long after this, the same zealous mathematicians added a collection of examples and methods of the higher forms of analysis, which utterly revolutionised the form of mathematical science, not at Cambridge alone, but throughout the country. In the parts added by Herschel and Babbage, that containing the finite differences by the former, and that containing a theory of functional equations by the latter, there was much that was striking and original. It was mainly by the writings of these eminent men, that the foundation was laid for that brilliant school of English analysts who are now, at least, the equals of their compeers on the Continent. It were invidious to name the living, but we may cherish a pardonable pride in being permitted to number two of this great school among the former Presidents of our Society, and today we hope to add a third to the list.
We have thus traced the career of Herschel up to, and just beyond, the time when he took his Bachelor's degree at Cambridge; and we shall merely add, that the authorities of the venerable College to whose fostering care he owed so much, cannot fail to read with peculiar pleasure the name of Herschel inscribed among the former fellows of their ancient house. Omitting here all notice of his earlier contributions to Nicholson's Philosophical Journal, and to the Cambridge Analytical Society of his own day, we come to his first communication to the Royal Society. It is dated from Slough, Oct. 6, 1812, and must therefore have been completed in the last long vacation of his undergraduateship, three months before his final examination for his degree. It bears the significant notice " Communicated by William Herschel." It related to "Some Remarkable Applications of Cotes' Theorem," and was probably suggested by an elegant theorem of Vieta's, printed in Woodhouse's Trigonometry, but it proceeds far beyond any conception which seemed to have presented itself to Vieta's mind. In 1814 we find a second paper of his in the same Transactions, but it is now communicated in his own right as a Fellow of the Society. It is a paper of remarkable elegance and of subtle conception, entitled "Considerations of Various Points of Analysis;" he therein devotes himself to the development of generating functions, a branch of analytical mathematics which had successfully engaged the attention of Laplace. It is in this paper that he first discloses the true bent and fashion of his maturer mind; the natural fruit of that early direction of his thoughts indicated by the incidents of the stone and the leaves already narrated. He. intimates that mathematical science having now made vast strides in the various details of its several distinctive branches, further progress was not now to be looked for in the direction of specific and isolated methods, but that the time was come when philosophers should look for some methods of expressing the results of their labours as a whole. He says, "Henceforth the attention of the scientific observer must be directed to those elevated stations from which distinct and extended views of the arrangement of this science as a whole can be obtained." It is this grouping of things together as a whole, which constituted an eminent characteristic of Herschel's philosophy. With him it is not the age of this thing or of that thing, but the oldest of all things aged.
This paper is followed up by other communications on mathematical analysis, all written in the same spirit, and pursuing the same vein of inquiry. Herschel, however, quitted Cambridge soon after his degree, and placed himself in the hands of an eminent Chancery barrister in London with the view of qualifying himself for practice at the Bar. The arrangement in itself was natural enough, for the higher wranglers in the Cambridge tripos of Herschel's time, who selected the Law for their profession, almost universally rose to eminent stations among the chiefs in Chancery, or on the judicial bench. The names of Copley, Pollock, Bickersteth, Maule, Page Wood, and a host of others, bear witness to the happy results of the Cambridge training. And if a less amount of success has been attained by them in more recent times, whatever the other reasons may be, we venture to say that one of the efficient causes may be found in the modern comparative abandonment of the geometrical method. The educational effects of the continued study of abstract analysis do not easily comport with the composite circumstances of ordinary life, wherein lies the chief field for the application of the Law. Be this as it may, a mind constituted like Herschel's, and trained, as his had been trained, in the love of generalisation, was not likely to submit voluntarily to the mastery of isolated facts and precedents bound together apparently by no ties of a general law. Whether this was the cause or not, certain it is that he emancipated himself from studies which were essential to success at the English Bar.
Nevertheless, his removal from Cambridge to London proved to be the turning point of his scientific career. For it was in London that he made his acquaintance with Wollaston and with South. Wollaston completely fascinated him by the breadth and accuracy of his scientific pursuits, and fostered, if not awakened, in him that dormant taste for Chemistry and general Physics which wanted but the magic touch of such a mind, to kindle into the intellectual passion of a life. We think we may aver this with safety, for we have heard him more than once say that he became an Astronomer, not so much from any conscious and specific aptitude for the work, as through a loyal desire to re-examine and complete his father's work had he followed simply the natural bias of his mind, his pursuits would have been the study of Chemistry and of the Theory of Light.
Hence it is that in 1819 we find him communicating to Nicholson's Philosophical Journal a very remarkable article on Hyposulphurous Acid and its compounds. He therein details the important and indeed the cardinal discovery of that property of hyposulphite of soda, which, had it been known to Wedgwood or Davy, would have anticipated the photographic invention of Neipce and Daguerre by a quarter of a century. "Muriate of silver freshly precipitated," he says, "dissolves in this salt (hyposulphite of soda) when in somewhat concentrated solution, in large quantity, and almost as readily as sugar in water." What would Davy have given for the knowledge of this discovery, when he shut up his Sun – pictures in the darkness of a portfolio, only to elude him like ghosts in daylight? This was immediately followed by his first paper on physical optics, a subject which, as we have said, had a peculiar attraction for him; and here again we find an instance of his love of generalisation, for he applies the known action of grooved or striated surfaces on light to explain the iridescence of mother-of-pearl. Then, again, in the same year, there is a communication made to the Royal Society, on another optical question, much more recondite in its nature: he investigates the coloured lemniscates produced by certain biaxal crystals, when submitted to the passage of polarised light, and he proposes certain simple and elegant devices for the observation of these and similar gorgeous phenomena sometimes adopted even at the present day.
Lastly, there came a very important paper addressed to the Royal Society on the subject of aplanatic combinations for the object-glass of a telescope. There is great power and mathematical elegance in the management of the symbols, and the way in which he proposes to employ one of the disposable constants, so as to make the combination equally aplanatic within a considerable range of distance, is ingenious in the extreme. Practical opticians, however, have not generally availed themselves of this form, because other forms are of less difficult execution. Moreover, now that the manufacture of glass admits of apertures which Herschel never dreamed of, it is found that, however useful mathematical formulæ may be for a first approximation to the proper form of the components of a large object-glass, nevertheless when this approximation has been executed, the achromatism requires a subsequent manipulation, often expressed by the significant term "finishing," which must be effected by the skill and experience of the artist, rather than from abstract calculation. Still Herschel's investigation is effective for moderate apertures, and for a camera applied to landscapes might be very beautiful.
It was about this time also that the influence of Mr. South produced a decided effect upon his pursuits. That gentleman was possessed of some of the best achromatic telescopes of the day, small as they were compared with the gigantic machines of more modern times. He had a passion for practical Astronomy, and had by himself done some very creditable work on double stars. It was a happy circumstance for him and for science that he could be associated with such a mind as Herschel's. Their conjoint labours commenced about the same time as the first formation of our own Society, South himself having a large share in the scheme which has been so successfully developed during the last fifty years. The venerable Sir William Herschel was its first President, and his illustrious son its first Foreign Secretary. The early lessons in the historic house had been well learnt, and the teacher was well rewarded, by this happy and significant association.
Herschel's first communications to the Astronomical Society were efforts made to relieve practical astronomers in certain numerical calculations at once intricate and laborious. The first related to the occultations of fixed stars by the Moon; and the second to the arrangement of tables for the reduction of certain stars to their mean places at an assigned epoch. The first involves mainly geometrical considerations; but to handle the latter with any success, requires all the resources of a knowledge of some of the most intricate questions in astronomical dynamics.
From 1821 to 1823 he was associated with Mr. South in Blackman Street, Southwark, in the reobservation of the double stars discovered by his father. He had himself commenced the work as early as 1816, deeply interested in those marvellous movements of Sun around Sun which had been brought to light by the labours at Slough. He now resumed them in London with instruments in Mr. South's possession, described by Mr. Baily, the President of our Society in 1826, as "a princely collection, of exquisite workmanship, and considerable magnitude, such as have never yet fallen to the lot of a private individual." The result of their joint labours is printed in the Transactions of the Royal Society, and their importance and success were acknowledged by medals from that learned body, and subsequently from our own, and by the Lalande Medal of the French Institute. It is a matter of scientific interest to observe that a similar acknowledgment was at the same time made by our Society to Wilhelm Struve for the first-fruits of similar labours, undertaken with Fraunhofer's far-famed achromatic telescope at Dorpat. To this work Struve says he was fired by the noble example of William Herschel.
The conjoint labours of the two astronomers came to an end by the removal of South to the neighbourhood of Paris, in search of a clearer atmosphere than that which enveloped our own metropolis even half a century ago; the result was pretty much the same as that experienced subsequently by other observers, namely, that he would have been equally successful at home. Meanwhile, and after the termination of his travels on the Continent of Europe, Herschel resumed at Slough the dutiful but self-imposed and gigantic task of re-examining the double stars and nebulæ which through a long life had formed the solicitude of his illustrious father. It is interesting to read his own description of the instruments employed, he says,-
"The telescope with which the following observations were made is one of that construction which has been called the 'front-view. The aperture, or clear polished surface of its mirror, is 18 inches, and its focal length 20 feet. It was constructed in the year 1820, under the joint superintendence of my father and myself, on the model of that used by him in his Sweeps of the Heavens, whose place it was intended to supply, the woodwork of the latter being greatly decayed by age. At the same time a new speculum was cast, with a view to preserve the old one, the figure of which was remarkably fine for the most delicate observations."
And then at a subsequent part of his Introduction he proceeds to say: "It will now be right to mention more particularly the mo-difications I have introduced into my father's system of sweeping, – modifications rendered necessary by the loss of my aunt, MISS CAROLINE HERSCHEL'S personal assistance, on whom the task of reading and registering the Polar Distance and Right Ascensions of objects, writing down the remarks and descriptions, warning the observer of expected stars, and finally reducing and calculating the whole, used invariably to devolve. Unsupported by such aid, I am under the necessity of recording the observations myself; an inconvenience of the worst kind, not only as it diminishes by at least one-half the number of the objects that can be taken, but because the frequent admission of extraneous light to the eye is fatal to observations of the fainter nebulæ."
These labours extended as far as a Sixth Catalogue, which was printed in the ninth volume of the Memoirs of the Royal Astronomical Society in 1835. Meanwhile observations of the nebulæ visible in these northern regions were proceeding steadily; but these were reserved for the Transactions of the Royal Society, with the exception of a most interesting and admirable monograph on the Nebule of Orion and Andromeda, which will be found in the second volume of our own. We would earnestly recommend those who are interested in the history and progress of science, and especially Astronomical science, to read the introduction to such memoirs as these of the two Herschels, and of other great Astronomers of half a century back, among many other cogent reasons, especially in order to know how deeply modern observers are indebted to the ingenuity of their predecessors. Through their persevering ingenuity we have been gradually provided with instruments and methods which save an amount of labour and of anxious manipulation which appears incredible when understood. The smooth automatic motion of the magnificent astronomical machines of modern days, leaving both hands at liberty for adjusting the exquisite micrometers provided by the great artists of our day, will be all the better appreciated if they will master and reflect on the comparatively clumsy, harassing, and laborious, though efficient, expedients necessarily adopted by the two Herschels. It seems indeed to be an inevitable law imposed on the achievement of all great work, and on all great discoveries, that they shall be completed under disadvantages. Neither Dalton nor Davy nor Wollaston nor Faraday luxuriated in the appliances at this day found in our physical laboratories.
In 1827 we find John Herschel occupying the chair of the Royal Astronomical Society; and now commenced that series of presidential addresses, which we do not hesitate to say are unrivalled for instructive eloquence, masterly arrangement, and comprehensiveness of view. We shall here give one specimen, taken from the address which he delivered on presenting his friend, Baily, with the Society's medal for the completion of his superintendence of the Society's Catalogue of Stars. It would seem almost impossible for any imagination, however vivid, to clothe the description of so bare a thing as a catalogue of stars, with the amenities of human interest, and the graces of a poetic eloquence. Yet it will be seen that Herschel has accomplished this feat; and, probably, without the consciousness of attempt. He describes what, as an accomplished philosophical astronomer, he felt and no doubt had often felt before. "If we ask to what end magnificent establishments are maintained by states and sovereigns, furnished with master-pieces of art, and placed under the direction of men of first rate talent, and high-minded enthusiasm, sought out for those qualities among the foremost in the ranks of science: -if we demand cui bono? for what good a Bradley has toiled, or a Maskelyne, or a Piazzi worn out his venerable age in watching? the answer is, not to settle mere speculative points in the doctrine of the universe; not to cater for the pride of man, by refined inquiries into the remoter mysteries of nature, to trace the path of our system through infinite space, or its history through past and future eternities. These indeed are noble ends, and which I am far from any thought of depreciating; the mind swells in their contemplation, and attains in their pursuit, an expansion and a hardihood which fit it for the boldest enterprise. But the direct practical utility of such labours is fully worthy of their speculative grandeur. The stars are the land-marks of the universe; and amidst the endless and complicated fluctuations of our system, seem placed by its Creator as guides and records, not merely to elevate our minds by the contemplation of what is vast, but to teach us to direct our actions by reference to what is immutable in His works. It is, indeed, hardly possible to over-appreciate their value in this point of view. Every well-determined star, from the moment its place is registered, becomes to the astronomer, the geographer, the navigator, the surveyor, a point of departure which can never deceive or fail him, the same for ever and for all places, of a delicacy so extreme as to be a test for every instrument yet invented by man, yet equally adapted for the most ordinary purposes; as available for regulating a town clock, as for conducting a navy to the Indies; as effective for mapping down the intricacies of a petty barony, as for adjusting the boundaries of transatlantic empires. When once its place has been thoroughly ascertained and carefully recorded, the brazen circle, with which that useful work was done, may moulder, the marble pillar totter on its base, and the astronomer himself survive only in the gratitude of his posterity but the record remains, and transfuses all its own exactness into every determination which takes it for a ground-work, giving to inferior instruments, nay even to temporary contrivances, and to the observations of a few weeks or days, all the precision attained originally at the cost of so much time, labour, and expense."
His reply was, "You are quite right; it used to be said by the men in my workshop. Mr. Babbage made Clement, Clement made Whitworth, and Whitworth made the tools."
We enter now upon a summary of the labours, which this earnest philosopher prosecuted with undeviating diligence, during his sojourn at the Cape of Good Hope. We should have called this the most remarkable period of his life (and we have heard those who knew him best speak of it as the happiest), but, whether he is at Cambridge, or at Slough, or at Feldhausen, or at Collingwood, each period of that busy existence carries with it its own distinctive labours, and is full of its own philosophic interest.
The motives which impelled him to take this distant journey, cannot be better conveyed than in his own language, which we transcribe from the volume containing the results of his labours and his scientific musings in South Africa. He states that about the year 1825 he had commenced a re-examination of various observations which had occupied the greater part of his father's life; he then rearranged the whole, and communicated the results from time to time to the Royal, and Royal Astronomical Societies. He then goes on to say, "Having so far succeeded to my wish (the places of the objects thus determined proving on the whole satisfactory), and having by this practice acquired sufficient mastery of the instrument employed (a reflecting telescope of 184 inches clear aperture and 20 feet focus, on my father's construction), and of the delicate process of polishing the specula; being, moreover, strongly incited by the peculiar interest of the subject, and of the wonderful nature of the objects which presented themselves in the course of its prosecution, I resolved to attempt the completion of a survey of the whole surface of the heavens, and for this purpose to transport into the other hemisphere the same instrument which had been employed in this, so as to give a unity to the results of both portions of the survey, and to render them comparable with each other.
"Accordingly, having placed the instrument in question, as well as an equatoreally mounted achromatic telescope of 5 inches aperture and 7 feet focal length, by Tulley, which had served me for the measurement of double stars in England, together with such other astronomical apparatus as I possessed, in a fitting condition for work, and taking every precaution, by secure packing, to insure their secure arrival in an effective state, at their destination, they were conveyed (principally by water-carriage) to London, and there shipped on board the Mount Stewart Elphinstone, an East India Company's ship, in which, having taken passage for myself and family for the Cape of Good Hope, we
joined company at Portsmouth, and sailing thence on 13th November, 1833, arrived, by the blessing of Providence, safely in Table Bay on the 15th January, 1834." He then proceeds to explain the position of the residence he was fortunate enough to acquire by purchase, and adds that all preparations were "pushed forward with such effect, that, on the 22nd of February, I was enabled to gratify my curiosity by a view of a Crucis, the Nebula about Argûs, and some other remarkable objects, in the 20-feet reflector; and on the night of the 5th of March to commence a regular course of sweeping."
The vast mass of scientific labour completed during the next four busy years at Feldhausen may be properly described by giving a very rapid summary of the principal contents of the volume of the Cape Observations; a work which we venture to say is not surpassed in varied interest or importance by any astronomical work in existence. It was not published until 1847, nine years after the author's return to England, for the very cogent reasons assigned by himself: "The whole of the observations, as well as the entire work of reducing, arranging, and preparing them for the press, has been executed by myself." Perhaps none but practical astronomers can form a true conception of the incredible amount of personal and tedious labour implied by these words. Nine years, indeed, would not have been sufficient to complete the task, had not the work been first planned with a careful sagacity, and then carried out with undeviating perseverance.
The first chapter of the volume, consisting of 164 quarto pages, records the history of his observations of the Southern Nebulæ and clusters of stars. They are then systematically arranged, in a catalogue, containing the places of 1707 of these objects, all reduced to the epoch 1830, and each object bearing, in condensed literal symbols, a complete description. But this gives a very inadequate view of his labours among the Southern Nebule. He selects the most remarkable objects among them, delineates them with a scrupulous care, and then makes charts and catalogues of the numerous small stars in their neighbourhood, with the view of the future detection of any changes in these mysterious bodies. Completeness and utility are evidently the aims which direct and sustain his labours. His delineations and descriptions of the great Nebula of Orion, and of the region surrounding the remarkable star Argûs, will long remain among the most remarkable of astronomical monographs; and the latter is at this moment, nearly thirty years after its publication, of singular importance, as serving to establish the present non-variableness in the form of the adjacent Nebula, which has become a subject of dispute. The labour and the thought expended upon these detached and selected objects, probably equals that required for the observation of all the other Nebulæ combined. In a minute portion of the heavens, scarcely exceeding twice the space occupied by the Moon's disk, there are recorded the places of no less than 1216 stars. A spangle viewed at arm's length would eclipse the whole; yet he himself acknowledges it was the anxious work of several months.
These catalogues and charts are no sooner completed than he proceeds to discuss questions connected with them, and of the most absorbing interest. He inquires into the law of the distribution of these wonderful masses of glowing vapours, and these clusters of luminous suns. He thereby confirms his father's hypothesis that the Nebulæ are not irregularly scattered, and with no apparent law, hither and thither in the visible heavens, but are collected in a sort of canopy in the vertex or pole of that vast stratum of stars in which our Solar System finds its own position, buried in it, as he supposes, at a depth not greater than that of the average distance of an eleventh-magnitude star. These remarkable conclusions of the two Herschels are now being subjected to a re-examination by Mr. Proctor; but whatever the result may be, it is to the astounding industry and sagacity of the two Herschels alone, that so magnificent a conception has been entertained and brought into the cognizance of human thought.
The Nebulæ being at length dismissed, he proceeds to detail his observations of the double stars which had presented themselves during the sweeps for nebule. They are not dismissed until a regularly arranged catalogue of all that he had observed was completed, and ready for comparison by any subsequent astronomer. But there was a point of view which possessed for Herschel a peculiar charm. His father, half a century before, had commenced the observation of these singular objects – singular from their optical proximity, and still more so from the contrast of the colours of so many of these binary combinations. The motive which had invited the elder Herschel to the work, was a well-grounded hope that they might lead to the discovery of the distances of many stars from the Earth; this was the one great element which was wanting for the completion of his magnificent conception of the distribution of the universe of stars. He failed in this, but his failure herein was at length accompanied by the discovery that many of these stars moved round each other, and were to each other as revolving suns. John Herschel also had invented an elegant and practicable method of determining the forms of these orbits, and the periods which these suns take to complete their revolutions. In particular he had calculated the orbits of the two stars which form the combination γ Virginis, and he had the crowning satisfaction of seeing what he terms their perihelion appulse; he saw the two stars (as he had predicted) so close together, that his telescope was unable to detect their duality. Such visible reward of honest labour is not always accorded to the labourer. At the same time Herschel took the opportunity of improving certain imperfections which still adhered to his method of treatment. The period of revolution he ascertained to be approximately 182 years, not greatly exceeding the period of the planet Neptune round our Sun. If Neptune had been greatly larger than he is, would he have now shone by other than a reflected light? And if so, what sort of dynamical problem would the perturbation of our Earth and Moon have presented to the mathematical Astronomer?
In the course of the chapter which contains the catalogue and investigations of the double stars, Herschel makes one of those characteristic remarks which, while they enliven the narrative serve for us a still higher purpose; they exhibit the perseverance and the self-denial of the observer. He is referring to certain small regions of the heavens, which are barren of interesting objects, and he observes that it was well for himself to enter some remarks in his note-book "for the homely, but useful purpose of avoiding sleep, and that not unattended with the probability of broken bones." The well-known picture of the mounting of the Herschelian Telescope, will recur to the memory of our readers, and they will readily imagine that a fall from the observer's subaërial stage was by no means impossible, and assuredly dangerous if it occurred. It is by the path of labour and self-denial, that to great men is accorded the meed of immortality by their fellows.
The double stars and their stately revolutions and lustrous colours dismissed, in the next chapter he proceeds to describe the methods by which the magnitudes. or rather the relative brightness of the stars, may be observed and catalogued. In the library of the Astronomical Society there are preserved certain sheets of paper, on which he had marked the allineations and magnitudes of all the stars visible to his naked eye in the Northern hemisphere. The labour is less than it appears to be, owing to the comparatively small number of stars visible to unaided vision at one place; John Herschel accomplished it for the stars in both hemi-spheres. And if the detail of such occupation shall perchance raise the question whether such labour is misplaced for any man, and still more so for such a man as Herschel, let us listen to his own account of it.
"The subject," he says, "is one of the utmost physical interest. The grand phenomena of geology afford, as it seems to me, the highest presumptive evidence of changes in the general climate of our globe. I cannot otherwise understand alternations of heat and cold, so extensive at one epoch as to have clothed high Northern latitudes with a more than tropical luxuriance of vegetation; at another to have buried vast tracts of Middle Europe, now enjoying a genial climate, and smiling with fertility, under a glacier crust of enormous thickness. Such changes seem to point to some cause more powerful than the mere local distribution of land and water (according to Mr. Lyell's views) can well be supposed to have been. In the slow secular variations of our supply of light and heat from the Sun, which in the immensity of time past may have gone to any extent, and succeeded each other in any order, without violating the analogy of sidereal phenomena which we know to have taken place, we have a cause, not indeed established as a fact, but readily admissible as something beyond a bare possibility, fully adequate to the utmost requirements of geology. A change of half a magnitude in the lustre of the Sun, regarded as a fixed star, spread over successive geological epochs, – now progressive, now receding, now stationary, according to the evidence of warmer or colder general temperature which geological research has disclosed, or may hereafter reveal, is what no Astronomer would now hesitate to admit as in itself a perfectly reasonable and not improbable supposition. Such a supposition has assuredly far less of extravagance about it than the idea that the Sun, by its own proper motion, may, in indefinite ages past, have traversed regions so crowded with stars as to affect the climate of our planet by the influence of their radiations."
Such, then, was one of the reasons which actuated both the Herschels in their midnight survey of the stars; and we may, in passing, mention another instance of J. Herschel's methodical diligence in this, that he had proposed to himself to devote the enforced leisure of the voyage home by sea, to the completion of these comparisons of stellar brightnesses, and so carry on the sequence of these relations to the stars of the north, not visible in South Africa. Bad weather, however, interfered with the consecutiveness of the work, and two nights only were favourable to his design. He says:
"It was my earnest wish to have carried on these comparisons during the whole of our homeward voyage (the observations being easily made on ship-board) so as to interweave in sequences sufficiently numerous and extensive, at least all the most conspicuous stars of both hemispheres; but in this I was disappointed, at least to that extent; as a totally overcast state of the sky prevailed from the day of our departure from Table Bay, until we reached nearly the latitude of St. Helena, with the exception of a single fine night on the Equator, on the 28th of March, 1838, advantage of which was taken to procure a short sequence, and several valuable comparisons of Southern stars with stars of equal or nearly equal lustre in good situations for European observations. But, with this exception, no other available opportunity occurred till the 14th and 15th of April, when two sequences were observed in latitude 17° and 18° north; but in these the more Southern stars were already too low for fair comparison."
After the discussion of the magnitudes and distribution of the stars in the Southern hemisphere, there comes a chapter upon Halley's Comet, containing many interesting observations on the physical features and dynamical action of cometary matter. He lived long enough to learn how great a stride has been made in our knowledge of such things, by the combined labours of such men as Kirchhoff, Huggins, and Schiaparelli; nevertheless, Herschel's discussion is replete with instruction. Similar remarks may be made with respect to his discussion of Sun-spots, and this is rendered all the more valuable from the impetus which it gave to Mr. De La Rue, Prof. Selwyn, and others, whereby they were induced to commence their invaluable labours on the Sun's autography. It is in this chapter that he suggests that form of first-surface reflecting eye-piece, which has completely revolutionised the method of viewing the Sun's photosphere.
Such is an outline, and a bare and imperfect outline, of the contents of this impressive volume. In perusing it we can with difficulty persuade ourselves that in reality it comprises the chief labours of four years only of a philosopher's life. Happily John Herschel, in this respect of devoted and intelligent labour, does not stand alone among the other great Astronomers of his age. The world hears but little of them at the time; they neither strive nor cry in the streets, but their labours remain as imperishable as the genius which inspires them.
As was natural and honourable to all concerned, he was greeted with enthusiasm on his return to England. There is something contagious in a great example, and one of Herschel's rewards consisted in this, that he inspired others with a zeal kindred to his own. In due time another Astronomer, Mr. Lassell, at his own expense, and with a more magnificent instrument, constructed like Herschel's with his own hands, expatriated him-self and his family to Malta for three years, under the hope of adding, if possible, to the discoveries of Herschel. In this he succeeded. Herschel must have had multitudinous thoughts pressing on his mind when, in 1849, he placed the Gold Medal of the Astronomical Society in Mr. Lassell's hands, saying, that "the simple facts are these: Mr. Lassell cast his own mirror (24 inches in diameter), polished it by machinery of his own contrivance, mounted it equatoreally in his own fashion, and placed it in an observatory of his own engineering. With this instrument he discovered the satellite of Neptune, the eighth satellite of Saturn, and reobserved the satellites of Uranus." He spoke, moreover, of Mr. Lassell as one of those, "who, by their personal example, press forward the advent of that higher phase of civilisation which some fancy may see not indistinctly dawning around them; a civilisation founded on the general and practical recognition of the superiority of the pleasures of mind over those of sense; a civilisation which may dispense with luxury and splendour, but not with the continual and rapid progress of knowledge in science and excellence in art." In mentioning Mr. Lassell, we gladly also recall to our memory similar scarcely less important labours of Mr. De La Rue.
In 1830, appeared his well-known Preliminary Discourse on the Study of Natural Philosophy; this was followed by a similar volume on Astronomy, both being published in Lardner's Cyclopedia. The latter, in 1849, was superseded by his larger and more important Outlines of Astronomy. No comment of ours is needful on these remarkable books; any one of the three would have sufficed to establish the scientific reputation of an ordinary writer. The first of them may be regarded as having contributed in no small measure to the fostering of that taste for scientific pursuits which has lately become a characteristic of our age. There is a sweet and dignified persuasion animating the volume, which, to a reader with a well-constituted mind, is irresistible. The last of the three, like the first, has become a classical work in our language; and has been the means of directing many hundreds of persons to the pursuit of a science which he knew to be inferior to none in its humanizing tendencies. These books are nothing short of a benefaction to mankind.
There are some passages in the former of these volumes which are displeasing to the disciples or admirers of Comte. Herschel, in all loyalty to his own science, had exposed certain shallow conceptions and scientific blunders of that talented but singular man; and he had no sympathy with his philosophy. He had a profound belief in causation as distinct from sequence, and in a great First Cause, and in many passages of his writings he had traced the evidence of a Personal Will in nature. Hence Herschel was not forgiven by a certain class of metaphysical writers. They were his sole literary antagonists personal enemies he had none.
His two treatises on Light and Sound were published in the Encyclopedia Metropolitana about the year 1830. The former has probably been read by every competent mathematician in the country, and every reader will have felt the charm of the half-suppressed enthusiasm which has carried him along. It contains the results of his own experimental investigations on the action of certain crystals on polarized light, plagiedral quartz, apophyllite, Rochelle-salt, for instance, results which have been confirmed and generalized since his early days. It would be a national advantage in the education of our higher classes of mathematical students if authors would take a leaf out of Herschel's books, and clothe the dry bones of their writings with a little judicious historical or experimental illustration.
But there is another volume of his not so widely known to the public as either of the former works. In this volume he collected many of his addresses to public bodies, in particular, to the Royal Astronomical Society, and to the British Association. It was published in 1857 by Longmans. We venture to say it is here that the great philosopher is seen in his happiest and most instructive mood, for these addresses contain the outpourings of a man walking at liberty among sympathizing associates, in his own home, and enamoured with its interest and beauties. Whether it is the affectionate yet wise earnestness with which he dilates on the comprehensive labours of a Bessel, or on the ponderous analysis of a Plana, or on the intelligent and loyal devotion of his friend, Baily, to the science and the society of his adoption, all teem with historical associations and pregnant suggestions which will richly reward the student who will devote his hours to their perusal.
In this volume, his review of Quetelet on Probabilities is reprinted; it favourably exhibits Herschel in the guise of a social philosopher, and it contains by far the clearest popular exposition of the principle of Least Squares that has yet appeared. An able and very recent writer on this difficult subject in the Transactions of the Royal Society, ascribes to this demonstration a character higher than popular.
The volume terminates with a collection of certain of his efforts in fugitive poetry. For John Herschel was a poet in a high sense, and of science he was emphatically the poet. Without imagination no man can become a truly great philosopher, and still less a truly great writer; and Herschel was both; and hence with him, as with many other of our ablest mathematicians, versifying became a solace and a recreation from severer work. There are passages in some of these little poems, and there are lines in his more formal translation of the Iliad, published at a much later period, which plainly indicate that had he chosen to make poetry the occupation of his life, he must have occupied a conspicuous place among the poets of his age. His sonnet on Sir William Hamilton in Ely Cathedral, and his verses entitled "A Dream which was not all a Dream," and which furnished one of his solaces in his latest hours, are sufficient evidence of the estimate we have made. Nevertheless it seems astonishing that a man with so cultivated an ear for music as he possessed, should have encumbered himself with the impossibilities of English hexameters, not feeling that the sweet and varied cadence of the Homeric metre cannot be transfused into our less flexible language. It is here, perhaps, that we may mention, as a pleasing trait of the habits of his life, that one of his last letters was written to his friend Sir Thomas Maclear at the Cape, and contained some popular nursery rhymes translated into Latin verse.
It is instructive to observe what sort of work Sir John Herschel reserved as the occupation of his old age. He could hardly expect at the age of seventy to make any positive advances in the science which had already occupied so many years of an active life. Besides the Translation of the Iliad, already referred to, he busied himself in arranging his own and his father's observations in a complete and collected form; he wrote, also, several very striking articles on some of the more popular aspects of science, in Good Words. These and a few other lectures and addresses he collected in a single volume, bearing the title Familiar Lectures – a little book, but eminently calculated to diffuse a taste for the study of the forces in constant operation around us; and in many of its paragraphs so suggestive as to arrest the attention even of those who are proficients in the subjects on which he writes. We entertain no doubt that the motive which impelled him to write this book was that which he had so well expressed in his address to the Educational Institute in South Africa, and which we have already quoted, namely, the importance which he attached to the diffusion of scientific knowledge, as a civilising agent, among the great masses of the people; for it was a characteristic of Herschel, that what he wrote, he wrote with settled purpose long entertained, and we may here be permitted to record an instance of this predetermination. We had occasion, a few years ago, to write to him to request a reference to some of the many passages in his writings wherein he had referred to the evidences of the action of a Personal Will in nature. The immediate reply was a little manuscript containing the transcription of all the passages which had been the object of our search, and which he had himself collected for his own purposes long before. A week or two before his death he again wrote with some solicitude on the same subject. This conscious and pervading intention of his life, is rendered still more evident by the state of completeness in which he left the record of all the most important undertakings of his scientific career. Thus, seven years before his removal, and therefore in his seventy-second year, he presented the Royal Society with a magnificent catalogue of all the nebulæ that had been recognised up to the date of its completion, whether observed by himself, by his father, or by any other astronomer.
Hence, again, during the last few years of his life he busied himself in doing what perhaps no other man could at any time have done so well, namely, in arranging a catalogue of all the double stars that were known to exist up to the most recent date. This catalogue was intended to contain what may be termed the natural history of every such star; that is to say, everything that had been observed or known concerning it. This grand and gigantic work was arranged and completed just before his death, so far as the catalogue itself is concerned. It contains about 10,000 double stars, all arranged in Right Ascension and Polar Distance, and the entire history of about 5000 of these stars is completed. He bequeathed this precious monument of his intelligent labour to the Astronomical Society; and we, to whom the editing is confided, shall most assuredly write with a loving and a truthful pen, on the last page of the volume the motto which in life pleased him so well, "COELIS EXPLORATIS."
John Herschel met with an amount of public recognition unusual in England. He might have been, had he wished it, President of the Royal Society, and he four times accepted the chair of the Royal Astronomical Society; the Society pleased him in its unpretendingness and solid work. He was appointed to the Mastership of the Mint, as Newton had been before him; but he fell upon the evil days of a reform in the place, and his sensitiveness was, in consequence, put to many a severe trial. He held the office for five years. At an early period of his life he received the recognition of a Hanoverian Knighthood; and at a later period the heritable title of a Baronetcy was accorded to him and his family. The scant measure of even this reward, raises difficult questions in the mind, and great searchings of heart. Naturally he was a member of almost every important learned society in either hemisphere. The French Institute honoured themselves by at last electing him a Foreign Member of their body. He married Margaret Brodie, daughter of Dr. Stewart, in 1829: she and a numerous family survive him. Two of his sons are already very favourably known in the realm of science, and their father lived to see one of them selected by the Council for election to the Fellowship of the Royal Society. It would have been a gratification to him, had he lived long enough, to see the other appointed to a very important Professorship in the North of England.
What was Herschel's true place in the philosophy and among the other great lights of his age, cannot be accurately fixed until his own generation shall have entirely passed away; the partialities and the prejudices of contemporaneous life, unavoidably warp and incapacitate the judgment, just as too close a proximity to a mass or a multitude is unfavourable to a correct appreciation of its proportions. The judgment passed by the able writer of his obituary notice in the Proceedings of the Royal Society, is naturally influenced by an affectionate remembrance of his friend, nevertheless it is not unsupported by less partial critics: he says, "British science has sustained a loss greater than any which it has suffered since the death of Newton." Long ago a somewhat similar estimate of his powers, both intellectual and moral, was made by one of the most competent among foreign savans, the celebrated Biot, to the effect that if he did not love John Herschel so much, he should not hesitate to say he was the ablest and most worthy of the successors of Laplace. But there is no need to make the comparison, his works are with us.
It is not for us to lift the veil which screens the sanctities of domestic life; but in the portrait we have sketched with a conscious feebleness, the reader will see what are the lineaments of a great Philosopher in his public relations; the mode, the aims, the hopes, the features, of his outer life. The noble example, the inevitable stimulativeness of such a life, are priceless. Though not lifting the veil of his home, we may say of him, that he there realised just what the reader would picture and would wish that life to be. He was a firm and a most active friend; he had no jealousies; he avoided all scientific feuds; he gladly accorded a helping hand to those who consulted him in scientific difficulties; he never discouraged, and still less disparaged, men younger than or inferior to himself; he was pleased with the appreciation of his works, but this was not an object of his solicitude; we quote the words of a discriminating critic, for they are not words of extravagance, when we say of him, that "his was a life full of the serenity of the sage, and the docile innocence of a child." Happy the pursuits that can lead to such results.
Herschel's whole life, like the lives of Newton and Faraday, confutes the assertion, and ought to remove the suspicion, that a profound study of Nature is unfavourable to a sincere acceptance of the Christian Faith.
Surrounded by an affectionate family, of which he had ever been the pride, the guide, and the life, John Herschel died as he had lived in the unostentatious exercise of a devout, yet simple, faith. The recollection of the long procession of his many friends, numbering among them some of the brightest and choicest intellects of his countrymen, still dwells vividly in our minds: what was mortal of him, we laid in Westminster Abbey, close by the side of Newton. The inscription on his monument is a happy but condensed expression, of the most deeply cherished thoughts of his life:-
C. P.
John Herschel was born at Slough, on March 7, 1792, in that house which his father's discoveries have rendered historical. A few traits of his boyhood, mentioned by himself in his maturer life, have been treasured up by those who were dear to him, and the record of some of them may satisfy a curiosity as pardonable as inevitable, which craves to learn through what early steps great men or great nations become illustrious. His home was singular, and singularly calculated to nurture into greatness any child born as John Herschel was, with natural gifts capable of wide development. At the head of the house there was the aged, observant, reticent philosopher; and rarely far away, was his devoted sister, Caroline Herschel, whose labours and whose fame are still cognisable as a beneficent satellite to the brighter light of her illustrious brother. It was in the companionship of these remarkable persons, and under the shadow of his father's wonderful telescope, that John Herschel passed his boyish years. He saw them, in silent but ceaseless industry, busied about things which had no apparent concern with the world outside the walls of that well-known house, but which, at a later period of his life, he, with an unrivalled eloquence, taught his countrymen to appreciate as foremost among those living influences which best satisfy and elevate the noblest instincts of our nature. What sort of intercourse passed between the father and the boy, may be gathered from an incident or two which he narrated as having impressed themselves permanently on the memory of his youth. He once asked his father what he thought was the oldest of all things. The father replied, after the Socratic method, by putting another question, "And what do you yourself suppose is the oldest of all things?" The boy was not successful in his answers, whereon the old astronomer took up a small stone from the garden-walk: "There, my child, there is the oldest of all the things that I certainly know." On another occasion his father is said to have asked the hoy, "What sort of things, do you think, are most alike?" The delicate, blue-eyed boy, after a short pause, replied, "The leaves of the same tree are most alike to each other." "Gather, then, a handful of leaves from that tree," rejoined the Philosopher, "and choose two that are alike." The boy failed; but he hid the lesson in his heart, and his thoughts were revealed after many days. These incidents may be trifles; nor should we record them here, had not John Herschel himself, though singularly reticent about his personal emotions, recorded them as having made a strong impression on his mind. Beyond all doubt, we can trace therein, first, that grasp and grouping of many things in one, implied in the stone as the oldest of things; and, secondly, that fine and subtle discrimination of each thing out of many like things, as forming the main features which characterised the habit of our venerated friend's philosophy.
In due time he was sent to Eton. It was close to his home; too close, indeed, for the jealous inspection of a mother's eye, for it was not long before she saw him maltreated by a stronger boy, and he was removed from the great school. Perhaps happily so, for the atmosphere of the public schools of that day was not suited for the nurture of a philosophical astronomer. Thus he was educated at home; and how successful that education was is written in the volumes and the manners of his life; for John Herschel became every way an accomplished man; he was a good and a fond scholar, an excellent modern linguist, a musician, and accomplished in the literature of the day. He always spoke affectionately of his tutor Mr. Rogers, but that gentleman does not appear to have been more successful in his attempts to impart a knowledge of geometry to his illustrious pupil than are the majority of the tutors of the present day; for John Herschel has been known to state that he learned Euclid accurately and diligently, but that "he knew no more of its real bearing and inten-tion than he knew of the man in the moon." This is a pity, but we have much reason to fear that this is a pitiably common result. Perhaps no one would be more amazed than the great Geometer of Alexandria himself, if he were to return to life and find that his books, written for mature philosophers, were put without note, comment, or preparation, into the hands of the boys of the nineteenth century, to flounder therein just as they may chance.
Be this as it may, Herschel was sent to Cambridge at the unusually early age of seventeen.
His University career would no doubt have been eminently successful to whatever college he might have been sent, but he must have found a great facility for the development of his natural bias in having been entered by his father at St. John's. That College was then, and has ever since been, conspicuous for the careful and judicious training and the generous encouragement of its younger members in every branch of academical learning, and we venture to say that in none was, or is, the Principia of Newton studied with greater intelligence or devotion. In Herschel's day, and for many subsequent years, this immortal work was presented to the students in the form of manu-scripts, in which the prescribed sections of the book were provided in an English dress. Herschel, however, made it his duty to read nearly the whole book in the original Latin. This is one instance out of many others, of that thoroughness of work which he displayed through life; it was the bent and genius of his mind; it was the happy tradition of his home. With such natural gifts developed by so able a training, it is no wonder that Herschel graduated as the Senior Wrangler of his year. Peacock, afterwards Dean of Ely, a man of rare ability, was the second on the list, followed by several others who became conspicuous in their day.
It is well known that great changes were imminent at Cambridge in the form of the study of mathematical learning at the time when Herschel was an undergraduate. From a variety of causes, not very easily understood, mathematical analysis had not made that advancement in England which had been so remarkable on the Continent ever since the death of Newton. The Cambridge professors and teachers acted as if they had a vested interest in the powerful geometry of the past; many of them were possessed of vast mental capacity, but they continued to encumber themselves with an old fluxional notation, and ponderous methods, which had long been discarded by the philosophers abroad. Waring at Cambridge and Lagrange at Turin were both born in the same year, 1736; both of them wrote – and wrote ably on the same subject, the Theory of Numerical Equations, yet the difference between the notations and even the methods of the two analysts, is something incredible to a person who has never taken the trouble of making the comparison. But it was not Cambridge alone which was in fault; a similar remark is applicable to the writings of Thomas Simpson in London and Euler at St. Petersburg. Yet the two Englishmen were probably endowed with natural genius comparable with those of their foreign compeers.
It was Woodhouse at Cambridge who first applied himself seriously and systematically to remove this stigma and this obstacle to all true scientific progress. He paved the way to ultimate success, not so much by his deeper and more controversial treatises, as by an elementary work on Trigonometry, which for the first time opened the door of the Continental forms of analysis, to the English student. This able and important, though elementary treatise, was published in the year when Herschel joined the University, and the influence which it had upon his mind is evidenced by the fact that the first contributions which he made, and that too during the years of his undergraduateship, to a scientific periodical of the day, were based on what he had read in Woodhouse's book. It was natural also that Herschel, even before his degree, should warmly espouse and effectually assist the cause in which his senior was so actively engaged.
One of Herschel's first works after his degree was an effort in the same direction, namely, to render the magnificent methods and results of analysis, which had so long been familiar to the minds of foreigners, accessible to the English student. With this view, and in conjunction with two of his university friends, he translated the best elementary treatise of that day on the Differential Calculus, adding, thereto, a valuable appendix on the cognate subject of Finite Differences from his own hands. Not long after this, the same zealous mathematicians added a collection of examples and methods of the higher forms of analysis, which utterly revolutionised the form of mathematical science, not at Cambridge alone, but throughout the country. In the parts added by Herschel and Babbage, that containing the finite differences by the former, and that containing a theory of functional equations by the latter, there was much that was striking and original. It was mainly by the writings of these eminent men, that the foundation was laid for that brilliant school of English analysts who are now, at least, the equals of their compeers on the Continent. It were invidious to name the living, but we may cherish a pardonable pride in being permitted to number two of this great school among the former Presidents of our Society, and today we hope to add a third to the list.
We have thus traced the career of Herschel up to, and just beyond, the time when he took his Bachelor's degree at Cambridge; and we shall merely add, that the authorities of the venerable College to whose fostering care he owed so much, cannot fail to read with peculiar pleasure the name of Herschel inscribed among the former fellows of their ancient house. Omitting here all notice of his earlier contributions to Nicholson's Philosophical Journal, and to the Cambridge Analytical Society of his own day, we come to his first communication to the Royal Society. It is dated from Slough, Oct. 6, 1812, and must therefore have been completed in the last long vacation of his undergraduateship, three months before his final examination for his degree. It bears the significant notice " Communicated by William Herschel." It related to "Some Remarkable Applications of Cotes' Theorem," and was probably suggested by an elegant theorem of Vieta's, printed in Woodhouse's Trigonometry, but it proceeds far beyond any conception which seemed to have presented itself to Vieta's mind. In 1814 we find a second paper of his in the same Transactions, but it is now communicated in his own right as a Fellow of the Society. It is a paper of remarkable elegance and of subtle conception, entitled "Considerations of Various Points of Analysis;" he therein devotes himself to the development of generating functions, a branch of analytical mathematics which had successfully engaged the attention of Laplace. It is in this paper that he first discloses the true bent and fashion of his maturer mind; the natural fruit of that early direction of his thoughts indicated by the incidents of the stone and the leaves already narrated. He. intimates that mathematical science having now made vast strides in the various details of its several distinctive branches, further progress was not now to be looked for in the direction of specific and isolated methods, but that the time was come when philosophers should look for some methods of expressing the results of their labours as a whole. He says, "Henceforth the attention of the scientific observer must be directed to those elevated stations from which distinct and extended views of the arrangement of this science as a whole can be obtained." It is this grouping of things together as a whole, which constituted an eminent characteristic of Herschel's philosophy. With him it is not the age of this thing or of that thing, but the oldest of all things aged.
This paper is followed up by other communications on mathematical analysis, all written in the same spirit, and pursuing the same vein of inquiry. Herschel, however, quitted Cambridge soon after his degree, and placed himself in the hands of an eminent Chancery barrister in London with the view of qualifying himself for practice at the Bar. The arrangement in itself was natural enough, for the higher wranglers in the Cambridge tripos of Herschel's time, who selected the Law for their profession, almost universally rose to eminent stations among the chiefs in Chancery, or on the judicial bench. The names of Copley, Pollock, Bickersteth, Maule, Page Wood, and a host of others, bear witness to the happy results of the Cambridge training. And if a less amount of success has been attained by them in more recent times, whatever the other reasons may be, we venture to say that one of the efficient causes may be found in the modern comparative abandonment of the geometrical method. The educational effects of the continued study of abstract analysis do not easily comport with the composite circumstances of ordinary life, wherein lies the chief field for the application of the Law. Be this as it may, a mind constituted like Herschel's, and trained, as his had been trained, in the love of generalisation, was not likely to submit voluntarily to the mastery of isolated facts and precedents bound together apparently by no ties of a general law. Whether this was the cause or not, certain it is that he emancipated himself from studies which were essential to success at the English Bar.
Nevertheless, his removal from Cambridge to London proved to be the turning point of his scientific career. For it was in London that he made his acquaintance with Wollaston and with South. Wollaston completely fascinated him by the breadth and accuracy of his scientific pursuits, and fostered, if not awakened, in him that dormant taste for Chemistry and general Physics which wanted but the magic touch of such a mind, to kindle into the intellectual passion of a life. We think we may aver this with safety, for we have heard him more than once say that he became an Astronomer, not so much from any conscious and specific aptitude for the work, as through a loyal desire to re-examine and complete his father's work had he followed simply the natural bias of his mind, his pursuits would have been the study of Chemistry and of the Theory of Light.
Hence it is that in 1819 we find him communicating to Nicholson's Philosophical Journal a very remarkable article on Hyposulphurous Acid and its compounds. He therein details the important and indeed the cardinal discovery of that property of hyposulphite of soda, which, had it been known to Wedgwood or Davy, would have anticipated the photographic invention of Neipce and Daguerre by a quarter of a century. "Muriate of silver freshly precipitated," he says, "dissolves in this salt (hyposulphite of soda) when in somewhat concentrated solution, in large quantity, and almost as readily as sugar in water." What would Davy have given for the knowledge of this discovery, when he shut up his Sun – pictures in the darkness of a portfolio, only to elude him like ghosts in daylight? This was immediately followed by his first paper on physical optics, a subject which, as we have said, had a peculiar attraction for him; and here again we find an instance of his love of generalisation, for he applies the known action of grooved or striated surfaces on light to explain the iridescence of mother-of-pearl. Then, again, in the same year, there is a communication made to the Royal Society, on another optical question, much more recondite in its nature: he investigates the coloured lemniscates produced by certain biaxal crystals, when submitted to the passage of polarised light, and he proposes certain simple and elegant devices for the observation of these and similar gorgeous phenomena sometimes adopted even at the present day.
Lastly, there came a very important paper addressed to the Royal Society on the subject of aplanatic combinations for the object-glass of a telescope. There is great power and mathematical elegance in the management of the symbols, and the way in which he proposes to employ one of the disposable constants, so as to make the combination equally aplanatic within a considerable range of distance, is ingenious in the extreme. Practical opticians, however, have not generally availed themselves of this form, because other forms are of less difficult execution. Moreover, now that the manufacture of glass admits of apertures which Herschel never dreamed of, it is found that, however useful mathematical formulæ may be for a first approximation to the proper form of the components of a large object-glass, nevertheless when this approximation has been executed, the achromatism requires a subsequent manipulation, often expressed by the significant term "finishing," which must be effected by the skill and experience of the artist, rather than from abstract calculation. Still Herschel's investigation is effective for moderate apertures, and for a camera applied to landscapes might be very beautiful.
It was about this time also that the influence of Mr. South produced a decided effect upon his pursuits. That gentleman was possessed of some of the best achromatic telescopes of the day, small as they were compared with the gigantic machines of more modern times. He had a passion for practical Astronomy, and had by himself done some very creditable work on double stars. It was a happy circumstance for him and for science that he could be associated with such a mind as Herschel's. Their conjoint labours commenced about the same time as the first formation of our own Society, South himself having a large share in the scheme which has been so successfully developed during the last fifty years. The venerable Sir William Herschel was its first President, and his illustrious son its first Foreign Secretary. The early lessons in the historic house had been well learnt, and the teacher was well rewarded, by this happy and significant association.
Herschel's first communications to the Astronomical Society were efforts made to relieve practical astronomers in certain numerical calculations at once intricate and laborious. The first related to the occultations of fixed stars by the Moon; and the second to the arrangement of tables for the reduction of certain stars to their mean places at an assigned epoch. The first involves mainly geometrical considerations; but to handle the latter with any success, requires all the resources of a knowledge of some of the most intricate questions in astronomical dynamics.
From 1821 to 1823 he was associated with Mr. South in Blackman Street, Southwark, in the reobservation of the double stars discovered by his father. He had himself commenced the work as early as 1816, deeply interested in those marvellous movements of Sun around Sun which had been brought to light by the labours at Slough. He now resumed them in London with instruments in Mr. South's possession, described by Mr. Baily, the President of our Society in 1826, as "a princely collection, of exquisite workmanship, and considerable magnitude, such as have never yet fallen to the lot of a private individual." The result of their joint labours is printed in the Transactions of the Royal Society, and their importance and success were acknowledged by medals from that learned body, and subsequently from our own, and by the Lalande Medal of the French Institute. It is a matter of scientific interest to observe that a similar acknowledgment was at the same time made by our Society to Wilhelm Struve for the first-fruits of similar labours, undertaken with Fraunhofer's far-famed achromatic telescope at Dorpat. To this work Struve says he was fired by the noble example of William Herschel.
The conjoint labours of the two astronomers came to an end by the removal of South to the neighbourhood of Paris, in search of a clearer atmosphere than that which enveloped our own metropolis even half a century ago; the result was pretty much the same as that experienced subsequently by other observers, namely, that he would have been equally successful at home. Meanwhile, and after the termination of his travels on the Continent of Europe, Herschel resumed at Slough the dutiful but self-imposed and gigantic task of re-examining the double stars and nebulæ which through a long life had formed the solicitude of his illustrious father. It is interesting to read his own description of the instruments employed, he says,-
"The telescope with which the following observations were made is one of that construction which has been called the 'front-view. The aperture, or clear polished surface of its mirror, is 18 inches, and its focal length 20 feet. It was constructed in the year 1820, under the joint superintendence of my father and myself, on the model of that used by him in his Sweeps of the Heavens, whose place it was intended to supply, the woodwork of the latter being greatly decayed by age. At the same time a new speculum was cast, with a view to preserve the old one, the figure of which was remarkably fine for the most delicate observations."
And then at a subsequent part of his Introduction he proceeds to say: "It will now be right to mention more particularly the mo-difications I have introduced into my father's system of sweeping, – modifications rendered necessary by the loss of my aunt, MISS CAROLINE HERSCHEL'S personal assistance, on whom the task of reading and registering the Polar Distance and Right Ascensions of objects, writing down the remarks and descriptions, warning the observer of expected stars, and finally reducing and calculating the whole, used invariably to devolve. Unsupported by such aid, I am under the necessity of recording the observations myself; an inconvenience of the worst kind, not only as it diminishes by at least one-half the number of the objects that can be taken, but because the frequent admission of extraneous light to the eye is fatal to observations of the fainter nebulæ."
These labours extended as far as a Sixth Catalogue, which was printed in the ninth volume of the Memoirs of the Royal Astronomical Society in 1835. Meanwhile observations of the nebulæ visible in these northern regions were proceeding steadily; but these were reserved for the Transactions of the Royal Society, with the exception of a most interesting and admirable monograph on the Nebule of Orion and Andromeda, which will be found in the second volume of our own. We would earnestly recommend those who are interested in the history and progress of science, and especially Astronomical science, to read the introduction to such memoirs as these of the two Herschels, and of other great Astronomers of half a century back, among many other cogent reasons, especially in order to know how deeply modern observers are indebted to the ingenuity of their predecessors. Through their persevering ingenuity we have been gradually provided with instruments and methods which save an amount of labour and of anxious manipulation which appears incredible when understood. The smooth automatic motion of the magnificent astronomical machines of modern days, leaving both hands at liberty for adjusting the exquisite micrometers provided by the great artists of our day, will be all the better appreciated if they will master and reflect on the comparatively clumsy, harassing, and laborious, though efficient, expedients necessarily adopted by the two Herschels. It seems indeed to be an inevitable law imposed on the achievement of all great work, and on all great discoveries, that they shall be completed under disadvantages. Neither Dalton nor Davy nor Wollaston nor Faraday luxuriated in the appliances at this day found in our physical laboratories.
In 1827 we find John Herschel occupying the chair of the Royal Astronomical Society; and now commenced that series of presidential addresses, which we do not hesitate to say are unrivalled for instructive eloquence, masterly arrangement, and comprehensiveness of view. We shall here give one specimen, taken from the address which he delivered on presenting his friend, Baily, with the Society's medal for the completion of his superintendence of the Society's Catalogue of Stars. It would seem almost impossible for any imagination, however vivid, to clothe the description of so bare a thing as a catalogue of stars, with the amenities of human interest, and the graces of a poetic eloquence. Yet it will be seen that Herschel has accomplished this feat; and, probably, without the consciousness of attempt. He describes what, as an accomplished philosophical astronomer, he felt and no doubt had often felt before. "If we ask to what end magnificent establishments are maintained by states and sovereigns, furnished with master-pieces of art, and placed under the direction of men of first rate talent, and high-minded enthusiasm, sought out for those qualities among the foremost in the ranks of science: -if we demand cui bono? for what good a Bradley has toiled, or a Maskelyne, or a Piazzi worn out his venerable age in watching? the answer is, not to settle mere speculative points in the doctrine of the universe; not to cater for the pride of man, by refined inquiries into the remoter mysteries of nature, to trace the path of our system through infinite space, or its history through past and future eternities. These indeed are noble ends, and which I am far from any thought of depreciating; the mind swells in their contemplation, and attains in their pursuit, an expansion and a hardihood which fit it for the boldest enterprise. But the direct practical utility of such labours is fully worthy of their speculative grandeur. The stars are the land-marks of the universe; and amidst the endless and complicated fluctuations of our system, seem placed by its Creator as guides and records, not merely to elevate our minds by the contemplation of what is vast, but to teach us to direct our actions by reference to what is immutable in His works. It is, indeed, hardly possible to over-appreciate their value in this point of view. Every well-determined star, from the moment its place is registered, becomes to the astronomer, the geographer, the navigator, the surveyor, a point of departure which can never deceive or fail him, the same for ever and for all places, of a delicacy so extreme as to be a test for every instrument yet invented by man, yet equally adapted for the most ordinary purposes; as available for regulating a town clock, as for conducting a navy to the Indies; as effective for mapping down the intricacies of a petty barony, as for adjusting the boundaries of transatlantic empires. When once its place has been thoroughly ascertained and carefully recorded, the brazen circle, with which that useful work was done, may moulder, the marble pillar totter on its base, and the astronomer himself survive only in the gratitude of his posterity but the record remains, and transfuses all its own exactness into every determination which takes it for a ground-work, giving to inferior instruments, nay even to temporary contrivances, and to the observations of a few weeks or days, all the precision attained originally at the cost of so much time, labour, and expense."
His reply was, "You are quite right; it used to be said by the men in my workshop. Mr. Babbage made Clement, Clement made Whitworth, and Whitworth made the tools."
We enter now upon a summary of the labours, which this earnest philosopher prosecuted with undeviating diligence, during his sojourn at the Cape of Good Hope. We should have called this the most remarkable period of his life (and we have heard those who knew him best speak of it as the happiest), but, whether he is at Cambridge, or at Slough, or at Feldhausen, or at Collingwood, each period of that busy existence carries with it its own distinctive labours, and is full of its own philosophic interest.
The motives which impelled him to take this distant journey, cannot be better conveyed than in his own language, which we transcribe from the volume containing the results of his labours and his scientific musings in South Africa. He states that about the year 1825 he had commenced a re-examination of various observations which had occupied the greater part of his father's life; he then rearranged the whole, and communicated the results from time to time to the Royal, and Royal Astronomical Societies. He then goes on to say, "Having so far succeeded to my wish (the places of the objects thus determined proving on the whole satisfactory), and having by this practice acquired sufficient mastery of the instrument employed (a reflecting telescope of 184 inches clear aperture and 20 feet focus, on my father's construction), and of the delicate process of polishing the specula; being, moreover, strongly incited by the peculiar interest of the subject, and of the wonderful nature of the objects which presented themselves in the course of its prosecution, I resolved to attempt the completion of a survey of the whole surface of the heavens, and for this purpose to transport into the other hemisphere the same instrument which had been employed in this, so as to give a unity to the results of both portions of the survey, and to render them comparable with each other.
"Accordingly, having placed the instrument in question, as well as an equatoreally mounted achromatic telescope of 5 inches aperture and 7 feet focal length, by Tulley, which had served me for the measurement of double stars in England, together with such other astronomical apparatus as I possessed, in a fitting condition for work, and taking every precaution, by secure packing, to insure their secure arrival in an effective state, at their destination, they were conveyed (principally by water-carriage) to London, and there shipped on board the Mount Stewart Elphinstone, an East India Company's ship, in which, having taken passage for myself and family for the Cape of Good Hope, we
joined company at Portsmouth, and sailing thence on 13th November, 1833, arrived, by the blessing of Providence, safely in Table Bay on the 15th January, 1834." He then proceeds to explain the position of the residence he was fortunate enough to acquire by purchase, and adds that all preparations were "pushed forward with such effect, that, on the 22nd of February, I was enabled to gratify my curiosity by a view of a Crucis, the Nebula about Argûs, and some other remarkable objects, in the 20-feet reflector; and on the night of the 5th of March to commence a regular course of sweeping."
The vast mass of scientific labour completed during the next four busy years at Feldhausen may be properly described by giving a very rapid summary of the principal contents of the volume of the Cape Observations; a work which we venture to say is not surpassed in varied interest or importance by any astronomical work in existence. It was not published until 1847, nine years after the author's return to England, for the very cogent reasons assigned by himself: "The whole of the observations, as well as the entire work of reducing, arranging, and preparing them for the press, has been executed by myself." Perhaps none but practical astronomers can form a true conception of the incredible amount of personal and tedious labour implied by these words. Nine years, indeed, would not have been sufficient to complete the task, had not the work been first planned with a careful sagacity, and then carried out with undeviating perseverance.
The first chapter of the volume, consisting of 164 quarto pages, records the history of his observations of the Southern Nebulæ and clusters of stars. They are then systematically arranged, in a catalogue, containing the places of 1707 of these objects, all reduced to the epoch 1830, and each object bearing, in condensed literal symbols, a complete description. But this gives a very inadequate view of his labours among the Southern Nebule. He selects the most remarkable objects among them, delineates them with a scrupulous care, and then makes charts and catalogues of the numerous small stars in their neighbourhood, with the view of the future detection of any changes in these mysterious bodies. Completeness and utility are evidently the aims which direct and sustain his labours. His delineations and descriptions of the great Nebula of Orion, and of the region surrounding the remarkable star Argûs, will long remain among the most remarkable of astronomical monographs; and the latter is at this moment, nearly thirty years after its publication, of singular importance, as serving to establish the present non-variableness in the form of the adjacent Nebula, which has become a subject of dispute. The labour and the thought expended upon these detached and selected objects, probably equals that required for the observation of all the other Nebulæ combined. In a minute portion of the heavens, scarcely exceeding twice the space occupied by the Moon's disk, there are recorded the places of no less than 1216 stars. A spangle viewed at arm's length would eclipse the whole; yet he himself acknowledges it was the anxious work of several months.
These catalogues and charts are no sooner completed than he proceeds to discuss questions connected with them, and of the most absorbing interest. He inquires into the law of the distribution of these wonderful masses of glowing vapours, and these clusters of luminous suns. He thereby confirms his father's hypothesis that the Nebulæ are not irregularly scattered, and with no apparent law, hither and thither in the visible heavens, but are collected in a sort of canopy in the vertex or pole of that vast stratum of stars in which our Solar System finds its own position, buried in it, as he supposes, at a depth not greater than that of the average distance of an eleventh-magnitude star. These remarkable conclusions of the two Herschels are now being subjected to a re-examination by Mr. Proctor; but whatever the result may be, it is to the astounding industry and sagacity of the two Herschels alone, that so magnificent a conception has been entertained and brought into the cognizance of human thought.
The Nebulæ being at length dismissed, he proceeds to detail his observations of the double stars which had presented themselves during the sweeps for nebule. They are not dismissed until a regularly arranged catalogue of all that he had observed was completed, and ready for comparison by any subsequent astronomer. But there was a point of view which possessed for Herschel a peculiar charm. His father, half a century before, had commenced the observation of these singular objects – singular from their optical proximity, and still more so from the contrast of the colours of so many of these binary combinations. The motive which had invited the elder Herschel to the work, was a well-grounded hope that they might lead to the discovery of the distances of many stars from the Earth; this was the one great element which was wanting for the completion of his magnificent conception of the distribution of the universe of stars. He failed in this, but his failure herein was at length accompanied by the discovery that many of these stars moved round each other, and were to each other as revolving suns. John Herschel also had invented an elegant and practicable method of determining the forms of these orbits, and the periods which these suns take to complete their revolutions. In particular he had calculated the orbits of the two stars which form the combination γ Virginis, and he had the crowning satisfaction of seeing what he terms their perihelion appulse; he saw the two stars (as he had predicted) so close together, that his telescope was unable to detect their duality. Such visible reward of honest labour is not always accorded to the labourer. At the same time Herschel took the opportunity of improving certain imperfections which still adhered to his method of treatment. The period of revolution he ascertained to be approximately 182 years, not greatly exceeding the period of the planet Neptune round our Sun. If Neptune had been greatly larger than he is, would he have now shone by other than a reflected light? And if so, what sort of dynamical problem would the perturbation of our Earth and Moon have presented to the mathematical Astronomer?
In the course of the chapter which contains the catalogue and investigations of the double stars, Herschel makes one of those characteristic remarks which, while they enliven the narrative serve for us a still higher purpose; they exhibit the perseverance and the self-denial of the observer. He is referring to certain small regions of the heavens, which are barren of interesting objects, and he observes that it was well for himself to enter some remarks in his note-book "for the homely, but useful purpose of avoiding sleep, and that not unattended with the probability of broken bones." The well-known picture of the mounting of the Herschelian Telescope, will recur to the memory of our readers, and they will readily imagine that a fall from the observer's subaërial stage was by no means impossible, and assuredly dangerous if it occurred. It is by the path of labour and self-denial, that to great men is accorded the meed of immortality by their fellows.
The double stars and their stately revolutions and lustrous colours dismissed, in the next chapter he proceeds to describe the methods by which the magnitudes. or rather the relative brightness of the stars, may be observed and catalogued. In the library of the Astronomical Society there are preserved certain sheets of paper, on which he had marked the allineations and magnitudes of all the stars visible to his naked eye in the Northern hemisphere. The labour is less than it appears to be, owing to the comparatively small number of stars visible to unaided vision at one place; John Herschel accomplished it for the stars in both hemi-spheres. And if the detail of such occupation shall perchance raise the question whether such labour is misplaced for any man, and still more so for such a man as Herschel, let us listen to his own account of it.
"The subject," he says, "is one of the utmost physical interest. The grand phenomena of geology afford, as it seems to me, the highest presumptive evidence of changes in the general climate of our globe. I cannot otherwise understand alternations of heat and cold, so extensive at one epoch as to have clothed high Northern latitudes with a more than tropical luxuriance of vegetation; at another to have buried vast tracts of Middle Europe, now enjoying a genial climate, and smiling with fertility, under a glacier crust of enormous thickness. Such changes seem to point to some cause more powerful than the mere local distribution of land and water (according to Mr. Lyell's views) can well be supposed to have been. In the slow secular variations of our supply of light and heat from the Sun, which in the immensity of time past may have gone to any extent, and succeeded each other in any order, without violating the analogy of sidereal phenomena which we know to have taken place, we have a cause, not indeed established as a fact, but readily admissible as something beyond a bare possibility, fully adequate to the utmost requirements of geology. A change of half a magnitude in the lustre of the Sun, regarded as a fixed star, spread over successive geological epochs, – now progressive, now receding, now stationary, according to the evidence of warmer or colder general temperature which geological research has disclosed, or may hereafter reveal, is what no Astronomer would now hesitate to admit as in itself a perfectly reasonable and not improbable supposition. Such a supposition has assuredly far less of extravagance about it than the idea that the Sun, by its own proper motion, may, in indefinite ages past, have traversed regions so crowded with stars as to affect the climate of our planet by the influence of their radiations."
Such, then, was one of the reasons which actuated both the Herschels in their midnight survey of the stars; and we may, in passing, mention another instance of J. Herschel's methodical diligence in this, that he had proposed to himself to devote the enforced leisure of the voyage home by sea, to the completion of these comparisons of stellar brightnesses, and so carry on the sequence of these relations to the stars of the north, not visible in South Africa. Bad weather, however, interfered with the consecutiveness of the work, and two nights only were favourable to his design. He says:
"It was my earnest wish to have carried on these comparisons during the whole of our homeward voyage (the observations being easily made on ship-board) so as to interweave in sequences sufficiently numerous and extensive, at least all the most conspicuous stars of both hemispheres; but in this I was disappointed, at least to that extent; as a totally overcast state of the sky prevailed from the day of our departure from Table Bay, until we reached nearly the latitude of St. Helena, with the exception of a single fine night on the Equator, on the 28th of March, 1838, advantage of which was taken to procure a short sequence, and several valuable comparisons of Southern stars with stars of equal or nearly equal lustre in good situations for European observations. But, with this exception, no other available opportunity occurred till the 14th and 15th of April, when two sequences were observed in latitude 17° and 18° north; but in these the more Southern stars were already too low for fair comparison."
After the discussion of the magnitudes and distribution of the stars in the Southern hemisphere, there comes a chapter upon Halley's Comet, containing many interesting observations on the physical features and dynamical action of cometary matter. He lived long enough to learn how great a stride has been made in our knowledge of such things, by the combined labours of such men as Kirchhoff, Huggins, and Schiaparelli; nevertheless, Herschel's discussion is replete with instruction. Similar remarks may be made with respect to his discussion of Sun-spots, and this is rendered all the more valuable from the impetus which it gave to Mr. De La Rue, Prof. Selwyn, and others, whereby they were induced to commence their invaluable labours on the Sun's autography. It is in this chapter that he suggests that form of first-surface reflecting eye-piece, which has completely revolutionised the method of viewing the Sun's photosphere.
Such is an outline, and a bare and imperfect outline, of the contents of this impressive volume. In perusing it we can with difficulty persuade ourselves that in reality it comprises the chief labours of four years only of a philosopher's life. Happily John Herschel, in this respect of devoted and intelligent labour, does not stand alone among the other great Astronomers of his age. The world hears but little of them at the time; they neither strive nor cry in the streets, but their labours remain as imperishable as the genius which inspires them.
As was natural and honourable to all concerned, he was greeted with enthusiasm on his return to England. There is something contagious in a great example, and one of Herschel's rewards consisted in this, that he inspired others with a zeal kindred to his own. In due time another Astronomer, Mr. Lassell, at his own expense, and with a more magnificent instrument, constructed like Herschel's with his own hands, expatriated him-self and his family to Malta for three years, under the hope of adding, if possible, to the discoveries of Herschel. In this he succeeded. Herschel must have had multitudinous thoughts pressing on his mind when, in 1849, he placed the Gold Medal of the Astronomical Society in Mr. Lassell's hands, saying, that "the simple facts are these: Mr. Lassell cast his own mirror (24 inches in diameter), polished it by machinery of his own contrivance, mounted it equatoreally in his own fashion, and placed it in an observatory of his own engineering. With this instrument he discovered the satellite of Neptune, the eighth satellite of Saturn, and reobserved the satellites of Uranus." He spoke, moreover, of Mr. Lassell as one of those, "who, by their personal example, press forward the advent of that higher phase of civilisation which some fancy may see not indistinctly dawning around them; a civilisation founded on the general and practical recognition of the superiority of the pleasures of mind over those of sense; a civilisation which may dispense with luxury and splendour, but not with the continual and rapid progress of knowledge in science and excellence in art." In mentioning Mr. Lassell, we gladly also recall to our memory similar scarcely less important labours of Mr. De La Rue.
In 1830, appeared his well-known Preliminary Discourse on the Study of Natural Philosophy; this was followed by a similar volume on Astronomy, both being published in Lardner's Cyclopedia. The latter, in 1849, was superseded by his larger and more important Outlines of Astronomy. No comment of ours is needful on these remarkable books; any one of the three would have sufficed to establish the scientific reputation of an ordinary writer. The first of them may be regarded as having contributed in no small measure to the fostering of that taste for scientific pursuits which has lately become a characteristic of our age. There is a sweet and dignified persuasion animating the volume, which, to a reader with a well-constituted mind, is irresistible. The last of the three, like the first, has become a classical work in our language; and has been the means of directing many hundreds of persons to the pursuit of a science which he knew to be inferior to none in its humanizing tendencies. These books are nothing short of a benefaction to mankind.
There are some passages in the former of these volumes which are displeasing to the disciples or admirers of Comte. Herschel, in all loyalty to his own science, had exposed certain shallow conceptions and scientific blunders of that talented but singular man; and he had no sympathy with his philosophy. He had a profound belief in causation as distinct from sequence, and in a great First Cause, and in many passages of his writings he had traced the evidence of a Personal Will in nature. Hence Herschel was not forgiven by a certain class of metaphysical writers. They were his sole literary antagonists personal enemies he had none.
His two treatises on Light and Sound were published in the Encyclopedia Metropolitana about the year 1830. The former has probably been read by every competent mathematician in the country, and every reader will have felt the charm of the half-suppressed enthusiasm which has carried him along. It contains the results of his own experimental investigations on the action of certain crystals on polarized light, plagiedral quartz, apophyllite, Rochelle-salt, for instance, results which have been confirmed and generalized since his early days. It would be a national advantage in the education of our higher classes of mathematical students if authors would take a leaf out of Herschel's books, and clothe the dry bones of their writings with a little judicious historical or experimental illustration.
But there is another volume of his not so widely known to the public as either of the former works. In this volume he collected many of his addresses to public bodies, in particular, to the Royal Astronomical Society, and to the British Association. It was published in 1857 by Longmans. We venture to say it is here that the great philosopher is seen in his happiest and most instructive mood, for these addresses contain the outpourings of a man walking at liberty among sympathizing associates, in his own home, and enamoured with its interest and beauties. Whether it is the affectionate yet wise earnestness with which he dilates on the comprehensive labours of a Bessel, or on the ponderous analysis of a Plana, or on the intelligent and loyal devotion of his friend, Baily, to the science and the society of his adoption, all teem with historical associations and pregnant suggestions which will richly reward the student who will devote his hours to their perusal.
In this volume, his review of Quetelet on Probabilities is reprinted; it favourably exhibits Herschel in the guise of a social philosopher, and it contains by far the clearest popular exposition of the principle of Least Squares that has yet appeared. An able and very recent writer on this difficult subject in the Transactions of the Royal Society, ascribes to this demonstration a character higher than popular.
The volume terminates with a collection of certain of his efforts in fugitive poetry. For John Herschel was a poet in a high sense, and of science he was emphatically the poet. Without imagination no man can become a truly great philosopher, and still less a truly great writer; and Herschel was both; and hence with him, as with many other of our ablest mathematicians, versifying became a solace and a recreation from severer work. There are passages in some of these little poems, and there are lines in his more formal translation of the Iliad, published at a much later period, which plainly indicate that had he chosen to make poetry the occupation of his life, he must have occupied a conspicuous place among the poets of his age. His sonnet on Sir William Hamilton in Ely Cathedral, and his verses entitled "A Dream which was not all a Dream," and which furnished one of his solaces in his latest hours, are sufficient evidence of the estimate we have made. Nevertheless it seems astonishing that a man with so cultivated an ear for music as he possessed, should have encumbered himself with the impossibilities of English hexameters, not feeling that the sweet and varied cadence of the Homeric metre cannot be transfused into our less flexible language. It is here, perhaps, that we may mention, as a pleasing trait of the habits of his life, that one of his last letters was written to his friend Sir Thomas Maclear at the Cape, and contained some popular nursery rhymes translated into Latin verse.
It is instructive to observe what sort of work Sir John Herschel reserved as the occupation of his old age. He could hardly expect at the age of seventy to make any positive advances in the science which had already occupied so many years of an active life. Besides the Translation of the Iliad, already referred to, he busied himself in arranging his own and his father's observations in a complete and collected form; he wrote, also, several very striking articles on some of the more popular aspects of science, in Good Words. These and a few other lectures and addresses he collected in a single volume, bearing the title Familiar Lectures – a little book, but eminently calculated to diffuse a taste for the study of the forces in constant operation around us; and in many of its paragraphs so suggestive as to arrest the attention even of those who are proficients in the subjects on which he writes. We entertain no doubt that the motive which impelled him to write this book was that which he had so well expressed in his address to the Educational Institute in South Africa, and which we have already quoted, namely, the importance which he attached to the diffusion of scientific knowledge, as a civilising agent, among the great masses of the people; for it was a characteristic of Herschel, that what he wrote, he wrote with settled purpose long entertained, and we may here be permitted to record an instance of this predetermination. We had occasion, a few years ago, to write to him to request a reference to some of the many passages in his writings wherein he had referred to the evidences of the action of a Personal Will in nature. The immediate reply was a little manuscript containing the transcription of all the passages which had been the object of our search, and which he had himself collected for his own purposes long before. A week or two before his death he again wrote with some solicitude on the same subject. This conscious and pervading intention of his life, is rendered still more evident by the state of completeness in which he left the record of all the most important undertakings of his scientific career. Thus, seven years before his removal, and therefore in his seventy-second year, he presented the Royal Society with a magnificent catalogue of all the nebulæ that had been recognised up to the date of its completion, whether observed by himself, by his father, or by any other astronomer.
Hence, again, during the last few years of his life he busied himself in doing what perhaps no other man could at any time have done so well, namely, in arranging a catalogue of all the double stars that were known to exist up to the most recent date. This catalogue was intended to contain what may be termed the natural history of every such star; that is to say, everything that had been observed or known concerning it. This grand and gigantic work was arranged and completed just before his death, so far as the catalogue itself is concerned. It contains about 10,000 double stars, all arranged in Right Ascension and Polar Distance, and the entire history of about 5000 of these stars is completed. He bequeathed this precious monument of his intelligent labour to the Astronomical Society; and we, to whom the editing is confided, shall most assuredly write with a loving and a truthful pen, on the last page of the volume the motto which in life pleased him so well, "COELIS EXPLORATIS."
John Herschel met with an amount of public recognition unusual in England. He might have been, had he wished it, President of the Royal Society, and he four times accepted the chair of the Royal Astronomical Society; the Society pleased him in its unpretendingness and solid work. He was appointed to the Mastership of the Mint, as Newton had been before him; but he fell upon the evil days of a reform in the place, and his sensitiveness was, in consequence, put to many a severe trial. He held the office for five years. At an early period of his life he received the recognition of a Hanoverian Knighthood; and at a later period the heritable title of a Baronetcy was accorded to him and his family. The scant measure of even this reward, raises difficult questions in the mind, and great searchings of heart. Naturally he was a member of almost every important learned society in either hemisphere. The French Institute honoured themselves by at last electing him a Foreign Member of their body. He married Margaret Brodie, daughter of Dr. Stewart, in 1829: she and a numerous family survive him. Two of his sons are already very favourably known in the realm of science, and their father lived to see one of them selected by the Council for election to the Fellowship of the Royal Society. It would have been a gratification to him, had he lived long enough, to see the other appointed to a very important Professorship in the North of England.
What was Herschel's true place in the philosophy and among the other great lights of his age, cannot be accurately fixed until his own generation shall have entirely passed away; the partialities and the prejudices of contemporaneous life, unavoidably warp and incapacitate the judgment, just as too close a proximity to a mass or a multitude is unfavourable to a correct appreciation of its proportions. The judgment passed by the able writer of his obituary notice in the Proceedings of the Royal Society, is naturally influenced by an affectionate remembrance of his friend, nevertheless it is not unsupported by less partial critics: he says, "British science has sustained a loss greater than any which it has suffered since the death of Newton." Long ago a somewhat similar estimate of his powers, both intellectual and moral, was made by one of the most competent among foreign savans, the celebrated Biot, to the effect that if he did not love John Herschel so much, he should not hesitate to say he was the ablest and most worthy of the successors of Laplace. But there is no need to make the comparison, his works are with us.
It is not for us to lift the veil which screens the sanctities of domestic life; but in the portrait we have sketched with a conscious feebleness, the reader will see what are the lineaments of a great Philosopher in his public relations; the mode, the aims, the hopes, the features, of his outer life. The noble example, the inevitable stimulativeness of such a life, are priceless. Though not lifting the veil of his home, we may say of him, that he there realised just what the reader would picture and would wish that life to be. He was a firm and a most active friend; he had no jealousies; he avoided all scientific feuds; he gladly accorded a helping hand to those who consulted him in scientific difficulties; he never discouraged, and still less disparaged, men younger than or inferior to himself; he was pleased with the appreciation of his works, but this was not an object of his solicitude; we quote the words of a discriminating critic, for they are not words of extravagance, when we say of him, that "his was a life full of the serenity of the sage, and the docile innocence of a child." Happy the pursuits that can lead to such results.
Herschel's whole life, like the lives of Newton and Faraday, confutes the assertion, and ought to remove the suspicion, that a profound study of Nature is unfavourable to a sincere acceptance of the Christian Faith.
Surrounded by an affectionate family, of which he had ever been the pride, the guide, and the life, John Herschel died as he had lived in the unostentatious exercise of a devout, yet simple, faith. The recollection of the long procession of his many friends, numbering among them some of the brightest and choicest intellects of his countrymen, still dwells vividly in our minds: what was mortal of him, we laid in Westminster Abbey, close by the side of Newton. The inscription on his monument is a happy but condensed expression, of the most deeply cherished thoughts of his life:-
JOANNES HERSCHEL
GULIELMI HERSCHEL
NATU OPERA FAMA
FILIUS UNICUS
"CŒLIS EXPLORATIS"
HIC PROPE NEWTONUM
REQUIESCIT
GENERATIO ET GENERATIO
MIRABILIA DEI NARRABUNT
PSALM CXLV. 4, 5.
VIXIT LXXIX. ANNOS
OBIIT UNDECIMO DIE MAII
A.D. MDCCCLXXI
GULIELMI HERSCHEL
NATU OPERA FAMA
FILIUS UNICUS
"CŒLIS EXPLORATIS"
HIC PROPE NEWTONUM
REQUIESCIT
GENERATIO ET GENERATIO
MIRABILIA DEI NARRABUNT
PSALM CXLV. 4, 5.
VIXIT LXXIX. ANNOS
OBIIT UNDECIMO DIE MAII
A.D. MDCCCLXXI
C. P.
John Frederick William Herschel's obituary appeared in Journal of the Royal Astronomical Society 32;4 (1872), 122-142.