Herschel

Front matter

SIR WILLIAM HERSCHEL. K.H., F.R.S.

From the picture in the National Portrait Gallery

CONTENTS.

Chapter 1

CHAPTER I.

EARLY YEARS.

"Universal history—the history of what man has accomplished in this world," says Carlyle, "is at bottom the history of the great men who have worked here." It must be admitted that Carlyle under-estimated the labours of the innumerable lesser workers in all departments of human activity, that he overlooked the part played by mighty world-movements in the realm both of thought and of action and the influence, even on great men, of what has been called the "time-spirit". Still, Carlyle's dictum—slightly qualified—is fundamentally true. A great personality is a creative force; he gives more to his age and to posterity than he receives from his age or the ages before him.

The history of astronomical science has been dominated in a remarkable degree by great creative personalities pioneers of astronomical discovery. In the front rank of these distinguished men, posterity has placed the name of William Herschel.

The illustrious astronomer came of an old German family, and was descended from one of three brothers, who, on account of steadfast devotion to the principles of Protestantism, were driven out of Moravia in the early part of the seventeenth century and compelled to seek refuge in Saxony. Hans Herschel, one of these brothers, settled at Pirna in Saxony. His second son, Abraham, born in 1651, acquired some distinction as a landscape-gardener. He learned gardening in the Elector's gardens at Dresden, and was afterwards employed, until his death in 1718, at the country-seat of Hohentziatz, in the principality of Anhalt-Zerbst, near Magdeburg. According to the short account of the family given by his illustrious grandson, "he had also a good knowledge of arithmetic, writing, drawing, and music". The last-named talent he bequeathed to his youngest son, Isaac, born at Hohentziatz on 14th January, 1707. In a brief review of his life which he left behind him, Isaac explains that it was the desire of his parents that he should follow in his father's line of life. After the death of his father, his elder brother Eusebius procured for him a situation in the gardens at Zerbst. But he had, in his own words, "lost all interest in gardening". "As I had already at Hohentziatz procured a violin and learned to play it by ear, I took proper lessons at Zerbst from an hautboy-player in the court-band. I also bought an hautboy, and was never so happy as when I could occupy myself with music." At the age of twenty-one, having decided to follow out music as his life-work, he went to Berlin to study. Finding "the Prussian service as a bandsman very bad and slavish," he went to Potsdam and took lessons for a year. From Potsdam he made his way to Brunswick, and thence to Hanover, where in August, 1731, he was engaged as hautboy-player in the Foot-guards. Hanover was destined to be his home, and in 1732 he married Anna Ilse Moritzen, the daughter of a citizen of the neighbouring town of Wenstadt. They had a family of ten, of whom six—four sons and two daughters—reached maturity. Of these, the third, Friedrich Wilhelm, born at Hanover on 15th November, 1738, became one of the greatest astronomers—indeed, one of the greatest men of science of all time.

Isaac Herschel seems to have been not only a man of high musical talent, but also of wide general culture. And despite the mothers dislike to learning and her lack of interest in intellectual things, all the members of the family—with the exception of the elder daughter, Sophia—inherited something of their father's ability. All four sons—Jacob, William, Alexander, and Dieterich—were eminent musicians; and the younger daughter, Caroline Lucretia, born 16th March, 1750, also accomplished in music, has earned a distinction only second to that of her distinguished brother, whose life-work she shared.

In her memoirs, written in old age, Caroline Herschel has given some interesting reminiscences of her father. "My father," she says, "was a great admirer of astronomy and had some knowledge of that science: for I remember his taking me on a clear frosty night into the street to make me acquainted with several of the most beautiful constellations, after we had been gazing at a comet which was then visible. And I well remember with what delight he used to assist my brother William in his various contrivances in the pursuit of his philosophical studies, among which was a neatly turned 4-inch globe, upon which the equator and ecliptic were engraved by my brother."

Despite his remarkable abilities, Isaac Herschel's whole life was spent in straitened circumstances: the post of bandsman in the Hanoverian Guards was not a lucrative one, and he was forced to augment his income by private tuition. In addition, his poverty was aggravated by chronic ill-health. After the battle of Dettingen in 1743, the Guards remained all night in the field. Isaac Herschel lay in a wet furrow, and as a result of that night's exposure, he contracted an asthmatical affection which impaired his health permanently and ultimately caused his premature death on 22nd March, 1767. Having no wordly goods to bequeath to his children, he sought to educate them as completely as his limited means would allow. From their earliest days, their father instructed them in music. William Herschel, in the short account of his life already referred to, tells us that his father "taught me to play on the violin as soon as I was able to hold a small one made on purpose for me. . . . Being also desirous of giving all his children as good an education as his very limited circumstances would allow, I was at a proper time sent to a school where, besides religious instructions, all the boys received lessons in reading, writing, and arithmetic; and as I very readily learned every task assigned me, I soon arrived at such a degree of perfection, especially in arithmetic, that the master of the school made use of me to hear younger boys say their lessons and to examine their arithmetical calculations."

At the age of fourteen and a half, young William Herschel entered the band of the Hanoverian Guards, on 1st May, 1753. His school life was at an end, but his education was only beginning. For over two years he received private lessons from a teacher named Hofschläger, who afterwards filled an important post at Hamburg. These lessons included languages, logic, ethics, and metaphysics. In those early years Herschel's thirst for knowledge seems to have been insatiable. "Although," he wrote in after years, "I loved music to excess and made considerable progress in it, I yet determined with a sort of enthusiasm to devote every moment I could spare to the pursuit of knowledge, which I regarded as the sovereign good, and in which I resolved to place all my future views of happiness in life."

This intellectual keenness was undoubtedly stimulated by the home environment. The mother, it is true, was hostile to intellectual ambition; she was a typical German Hausfrau, with no sympathy for aspirations; but, as before mentioned, Isaac Herschel encouraged his sons to talk and think on scientific and philosophical subjects. Caroline Herschel, then a little girl about five years of age, has given a very interesting glimpse into this period. "My brothers," she says, "were often introduced as solo performers and assistants in the orchestra of the court, and I remember that I was frequently prevented from going to sleep by the lively criticism on music on coming home from a concert, or conversations on philosophical subjects which lasted frequently till morning. . . . Generally their conversation would branch out on philosophical subjects, when my brother William and my father often argued with such warmth that my mother's interference became necessary when the names Leibnitz, Newton, and Euler sounded rather too loud for the repose of her little ones, who ought to be in school by seven in the morning."

The family circle was temporarily dispersed in the end of 1755. The times were stormy: the Seven Years' War was raging: a French invasion of England was expected, and the Hanoverian Guards were drafted across the North Sea. Accordingly, Isaac Herschel and his two sons left Hanover with the regiment. Embarking at Cuxhaven in the end of March 1756, they reached Chatham after a passage of sixteen days. The Guards were encamped successively at Maidstone, Coxheath, and Rochester. The Herschels' sojourn in England was by no means profitless. At Coxheath as well as at Maidstone, Herschel tells us, "my father, my eldest brother and myself made several valuable acquaintances with families that were fond of music, and which, on mine and my brother's return to England, proved of great service to us". At Maidstone, too, young William Herschel purchased a copy of Locke's "Essay on the Human Understanding". The perusal of this volume—the only thing he took with him from England—not only stimulated his interest in philosophy, but familiarised him with the English language.

In the end of 1756, the Guards were ordered back to Hanover, owing to the French threat to the country. Early in the following year, the regiment went into the campaign which culminated in the disastrous battle of Hastenbeck, 26th July, 1757. During the campaign they were many times forced to encamp in the wet furrows of ploughed fields. At Hastenbeck, the band was almost within reach of gunshot. Accordingly, Isaac Herschel advised his son to consider his own safety. Young Herschel thereupon, in his own words, "left the engagement and took the road to Hanover, but when I arrived there, I found that having no passport I was in danger of being pressed for a soldier". At that time Herschel was not technically a soldier, but a member of the band. Accordingly, he returned to the regiment, only to find that "nobody had time to look after the musicians—they did not seem to be wanted". The forced marches in the hot weather told on the lad's health, and his father advised him to leave the service." In September, my father's opinion was, that as on account of my youth I had not been sworn in when I was admitted to the Guards, I might leave the military service. Indeed, he had no doubt but that he could obtain my dismission, and this he after some time actually procured (in 1762) from General Spörcken, who succeeded General Sommerfeld."

The formal discharge paper is in existence and was printed for the first time in the "Collected Scientific Papers of Sir William Herschel," published in 1912. Dr. Dreyer, in his introductory sketch of Herschel's life, gives it as his opinion that "the existence of this formal discharge paper puts an end to the legend, too long and too readily believed, that he deserted from the army and that he received a formal pardon for this offence from George III on the occasion of his first audience in 1782". Whether Herschel was technically a deserter or not, it is very difficult to determine. In some notes furnished in later years to the editor of a Göttingen scientific periodical, Herschel said: "In my fifteenth year, I enlisted in military service, only remaining in the army, however, until my nineteenth year, when I resigned and went over to England." On the other hand, as already noted, he gives it as his father's view that he was not really a soldier at all. The formal discharge paper is dated 29th March, 1762, so that if William Herschel was ever actually a unit of the army, the discharge paper merely registered an accomplished fact: he had been out of the army and out of the country for four and a half years. Whether or not he was ipso facto a soldier by virtue of his position in the band, there can be no doubt that his departure for England was actuated by the desire to avoid being recalled to the colours. The evidence of his sister Caroline, then a little girl of seven, is decisive on this point. "I can now comprehend," she says, "the reason why we little ones were continually sent out of the way, and why I had only by chance a passing glimpse of my brother as I was sitting at the entrance of a street door, when he glided like a shadow along, wrapped in a greatcoat, followed by my mother with a parcel containing his accoutrements. After he had succeeded in passing unnoticed beyond the last sentinel at Herrenhausen, he changed his dress. . . . My brother's keeping himself so carefully from all notice was undoubtedly to avoid the danger of being pressed, as all unengaged young men were forced into the service. Even the clergy, unless they had livings, were not exempted."

At Hamburg, William Herschel was joined by his brother Jacob, and they embarked together for England. Arriving in London, they were greatly assisted by the friends whom they had made on the occasion of their previous visit. Nevertheless, they seem to have had a hard struggle. William Herschel had not half a guinea in his possession when he arrived in London. He went into a music shop and asked if he could be of any use in copying music. An opera was placed in his hands, and his promptitude in returning the copy so impressed the master of the shop that he kept him in his employment for a considerable time. Jacob Herschel contrived to gain a livelihood by teaching music. At length, the brothers found that they could not make a living in London. Accordingly, Jacob decided to return to Hanover in the autumn of 1759 to compete for a place in the court orchestra, which he was successful in gaining. For a time, William was, in his own words, "involved in great difficulties". Fortunately, however, he succeeded in procuring an appointment in Yorkshire. The Earl of Darlington, Colonel of the Durham militia, was desirous of obtaining a good musician as leader of the band. Herschel's name was brought to his notice, and he received the offer of the post, which he accepted and held for two years. These two years appear to have been very crowded. The brief entries in his diary record the composition of various symphonies, and he seems to have travelled a great deal over the north of England. In 1761 he applied for an important post in Edinburgh—"the manager of the concerts intending to leave that place"—and in anticipation of receiving the appointment, he terminated his engagement with Lord Darlington. However, Herschel was disappointed, as the concert manager altered his plans and decided to remain at his post. On arriving in Edinburgh, he records in his diary: "I was introduced to Mr. Hume, the metaphysician, and a few days after, at one of their regular concerts, I was appointed to lead the band of musicians, while some of my symphonies and solo concerts were performed. Mr. Hume, who patronised my performance, asked me to dine with him, and accepting of his invitation, I met a considerable company."

During the next few months, Herschel held temporary appointments at Newcastle and Pontefract, and in April, 1762, he accepted a post as manager of concerts at Leeds, where he remained for about four years. During this time, his public engagements multiplied, and he was rapidly acquiring a notable position as a teacher of music—in which he was greatly aided by his friend, Dr. Miller, organist at Doncaster, who advised him to compete for the post of organist at Halifax. In his memorandum for 7th March, 1766, Herschel states that the "Messiah" was performed at a private club of chorus singers in Halifax, where it was agreed to rehearse the same oratorio every other Friday in order to perform it in the church at the opening of a new organ erected there. "... I was a candidate for the place of organist, which, by the interest of the Messrs. Bates and many musical families I attended, I had great hopes to obtain". On 30th August, 1766, he was unanimously chosen as organist, but he had already been asked to allow himself to be nominated as organist of the Octagon Chapel at Bath, where a new organ was in process of erection. On 30th November, he played the organ at Halifax for the last time, and notes: "For the thirteen Sundays of my being organist, I was paid thirteen guineas". On 9th December he arrived at Bath; and on 4th October, 1767, the Octagon Chapel was opened, with Herschel as organist. He now entered on a busy and successful musical career. Pupils flocked to him, and sometimes his lessons numbered thirty-five a week. In addition, he composed anthems and psalm-tunes. Under the date 28th March, 1767, he noted, "Taken a house from 25th March to 29th September in Beaufort Square". Herschel had at last a settled home in England.

In his diary, under the date 5th April, Herschel notes: "Went into mourning for the death of my father". The vicissitudes through which the family passed have been graphically described by Caroline, who was, at her father's death, a girl of seventeen. From her earliest years, Caroline had two objects of idolatry—her father and her "dear brother William"—"the best and dearest of brothers". Her mother was unimaginative and unsympathetic, without interest in intellectual or graceful accomplishments. "It was her certain belief," Caroline records, "that my brother William would have returned to his country and my eldest brother not have looked so high if they had had a little less learning." Accordingly, Caroline became virtually the Cinderella of the family—from earliest years a little neglected maid-of-all-work. Her eldest brother and sister showed her little attention, and all her love was concentrated on the father who wished to give her "something like a polished education," and on her brother William, who invariably showed her kindness and affection.

After her father's death, she describes herself as having fallen into a "state of stupefaction". She "could not help feeling troubled about her future destiny". Her mother and her brother Jacob consistently under-estimated her; and domestic service seemed to be the only future in store for her. But William had not forgotten the little sister of early years. In 1771 he wrote home proposing that she should join him in Bath and become "a useful singer for his winter concerts and oratorios". Despite the opposition of her mother and the ridicule of her brother Jacob, the plan materialised. In the autumn of 1772 William Herschel arrived in Hanover, and at the close of a fortnight's stay, set off for England along with Caroline. They arrived in Bath on 28th August, 1772, and Caroline was at once installed as her brother's housekeeper. She received instruction in English and arithmetic as well as lessons in music. Already, too, a new interest had crept into Herschel's life. "By way of relaxation," his sister tells us, "we talked of astronomy and the bright constellations with which I had made acquaintance during the fine nights we spent on the Postwagen travelling through Holland."

Chapter 2

CHAPTER II.

HERSCHEL AS AMATEUR ASTRONOMER.

In his diary, under the date 1766, Herschel has the following entries: "February 19th. Wheatley. Observation of Venus." "February 24th. Eclipse of the Moon at 7 o'clock a.m. Kirby." These are the first indications of his interest in astronomy. He had from early years inherited from his father a taste for what might be called star-gazing, and along with this he had had from youth a bent towards mathematical as well as philosophical research. Even in his busiest years, he never ceased to read and study in his leisure hours. During the first years of his stay in England, his foremost care was to master the English language. Next he acquired Italian, which he believed to be essential to his profession. From this he passed on to the study of Latin and Greek. The latter language, however, he dropped, "as leading me too far from my other favourite studies by taking up too much of my leisure. The theory of music being connected with mathematics induced me very early to read in Germany all that had been written upon the subject of harmony; and when, not long after my arrival in England, the valuable book of Dr. Smith's 'Harmonics' came into my hands, I perceived my ignorance, and had recourse to other authors for information, by which I was drawn on from one branch of mathematics to another." After perusing Smith's "Harmonics," he became possessed of a copy of the same author's "System of Optics". The study of optics passed into that of astronomy, which was stimulated by "Astronomy Explained upon Sir Isaac Newton's Principles," by James Ferguson, the Scottish astronomer. Herschel's early interest in the latter science seems to have been revived. So enthusiastic did he become that, in his own words, "I resolved to take nothing upon trust, but to see with my own eyes all that other men had seen before". At the time of his sister's arrival at Bath, Herschel had plunged in earnest into the study of astronomy. "He went to sleep," she tells us, "buried under his favourite authors; and his first thoughts on rising were how to obtain instruments for viewing these objects himself of which he had been reading." In May, 1773, he procured some object-glasses which he fitted into pasteboard tables. Caroline Herschel, who at that time had no interest whatever in telescopic astronomy, tells us: "I was much hindered in my musical practice by my help being continually wanted in the execution of the various contrivances, and I had to amuse myself with making the tube of pasteboard for the glasses which were to arrive from London". At length, Herschel completed this instrument, 4 feet long, which magnified forty times. With this, he records, he observed Jupiter and its satellites. Afterwards he made other two refractors—15 and 30 feet long respectively. Herschel soon discovered for himself the great weakness of the refracting telescope—the long tubes which were then necessary in order to counteract the effect of chromatic aberration. Finding the long tubes almost "impossible to manage," he turned his attention to the reflecting telescope, and in September hired a two-foot Gregorian reflector, which he found much more convenient. He decided to acquire a mirror of his own, for a tube 5 or 6 feet long. On enquiry he found there were none in the market of so large a size. "A person," his sister tells us, "offered to make one at a price much above what my brother thought proper to give." Herschel, however, was not discouraged. He became acquainted with a Quaker resident in Bath, who had in his leisure hours amused himself with efforts at the construction of mirrors. This individual had apparently failed in his endeavours—"his knowledge," Herschel noted, in that indifferent English which characterised him throughout his lifetime, "being very confined"—and had decided to dispose of his tools and half-finished mirrors. Herschel accordingly purchased his stock, and plunged at once into the work of telescope-making.

All through the winter 1773-4 and the following spring and summer, Herschel laboured at his new line of work, in the midst of his busy professional life. By 21st October, he had succeeded in casting mirrors for a two-foot reflector, and by the middle of December, "it became necessary to think of mounting these mirrors". Early in the new year, he placed a 5½-foot mirror into a square wooden tube, but finding the adjustment of the Gregorian telescope very troublesome, he decided to have recourse to the Newtonian form. On 1st March, 1774, he made his first entry in his astronomical journal, stating that he had viewed "the lucid spot in Orion's sword belt" and the ring of Saturn, which appeared "like two slender arms". The success of this instrument encouraged Herschel to construct other telescopes of the Newtonian form, and at length he succeeded in making a 7-foot telescope with "many different object mirrors". On 1st May, 1776, he observed Saturn's ring and two belts "with great perfection".

The memoirs of his sister give us some idea of his unflagging energy. With sorrow, natural from the house-keeper's point of view, Caroline saw almost every room in the house transformed into a workshop. A tube and stand were set up in a handsomely-furnished drawing room; while Alexander Herschel, the younger brother, who had now come to reside in Bath, erected a huge turning-machine in a bedroom, for turning eye-pieces and grinding glasses. "Every leisure moment was eagerly snatched at for resuming some work which was in progress, without taking time for changing dress, and many a lace ruffle was torn or bespattered by molten pitch." From now onwards, Caroline proved herself the devoted assistant and helper of her brother, keeping house for him, assisting him in music and in his work of telescope-making. "By way of keeping him alive," she says, "I was constantly obliged to feed him by putting the victuals by bits into his mouth". This was once the case when, in order to finish a seven-foot mirror, he had not taken his hands from it for sixteen hours together. "In general he was never unemployed at meals, but was always at those times contriving or making drawings of whatever came in his mind. Generally I was obliged to read to him whilst he was at the turning lathe or polishing mirrors, 'Don Quixote,' 'Arabian Nights' Entertainments,' the novels of Sterne, Fielding, etc.; serving tea and supper without interrupting the work with which he was engaged. . . . and sometimes lending a hand. . . . My brother Alex, was absent from Bath for some months every summer, but when at home he took much pleasure to execute some turning or clockmaker's work for his brother."

Herschel was not content with the construction of one or two telescopes. The work went on during the remainder of his stay in Bath. How he contrived to continue the construction of telescopes while making long-continued surveys of the heavens—all in the spare time which he was able to snatch from his busy career as a professional musician—must always remain more or less of a mystery.

His earliest observations were on the Moon and planets. In 1776 he made a number of examinations of the lunar surface, and three years later was engaged in measuring the heights of the lunar mountains. From 1774 onwards, he carefully observed Saturn, and in April, 1777, he commenced to make sketches in pen and ink of the markings on the surface of Mars, and in the following year of those on Jupiter. His attention was not confined to the members of the Solar System, and in 1777 he commenced a series of observations on the variable star, Omicron—or Mira—Ceti. As early as 1778 he had conceived the idea of attempting to determine by measures of close doubles the annual parallax or apparent displacement of a star in the sky due to the earth's change of position as it moves in its orbit. From this parallax, the distance of a star is determined. Before Herschel's time, astronomers had made many attempts to measure stellar parallax, but owing to the great distance of even the nearest stars and the consequent smallness of the displacement, and also because of the comparative imperfection of astronomical instruments, all these efforts had failed. Herschel was particularly interested in the problem, and made several attempts to solve it, but was unsuccessful. It was not until 1838 that the first determinations of stellar parallax were made. Herschel's attempts were not altogether in vain, however, for while tackling the problem, he was led to the study of double stars, which resulted, after many years, in one of his greatest discoveries. At the same time he executed his first review of the heavens with his 7-foot Newtonian reflector. The review only extended to the first four magnitudes: it was in itself a mere beginning, but it was the starting-point of his work on stellar distribution.

Herschel soon became known to the cultured public of Bath, not only as a prominent musician, but also as an amateur astronomer of considerable eminence. His introduction to literary and scientific circles in the town was a somewhat unconventional one. In his diary, under the date December, 1779, there occurs the following entry: "About the latter end of this month, I happened to be engaged on a series of observations on the lunar mountains, and the Moon being in front of my house late in the evening, I brought my 7-foot reflector into the street, and directed it to the object of my observations. While I was looking into the telescope, a gentleman coming by the place where I was stationed stopped to look at the instrument. When I took my eye off the telescope, he very politely asked if he might be permitted to look in, and expressed great satisfaction at the view. Next morning, the gentleman, who proved to be Dr. Watson, jun. (now Sir William), called at my house to thank me for my civility in showing him the Moon, and told me that there was a Literary Society then forming at Bath and invited me to become a member, to which I readily consented."

About the middle of January, 1780, this society—the Philosophical Society of Bath—began its meetings. Herschel not only attended these, but contributed a considerable number of papers—thirty-one in all—in the course of the next two years. One or two of these dealt with astronomical subjects, such as the height of the lunar mountains, and the variable star Mira Ceti; but most of them were on metaphysical and physical subjects, such as "The Utility of Speculative Enquiries," "On the Existence of Space," and "Experiments in Light". These were nearly all published in 1912 in the "Collected Scientific Papers of Sir William Herschel". Through Dr. Watson's influence, Herschel was introduced to scientific circles in London, and he forwarded four communications to the Royal Society before he was elected a Fellow. These were, a paper on "Mira Ceti," read 11th May, 1780; on the "Mountains of the Moon," read the same day; on the "Rotation of the planets on their Axes, with a view to determine whether the Earth's diurnal motion is perfectly equable,"—a remarkable and ingenious paper bearing the stamp of his own peculiar methods of investigation—read 11th January, 1781; and "Account of a Comet," read 26th April, 1781.