SIR JOHN FREDERICK WILLIAM HERSCHEL, BART.
(From a portrait painted by Pickersgill for St. John’s College, Cambridge.)
“John and I,” she told his wife, “were the most affectionate friends, and many a half or whole holiday spent with me was dedicated to making experiments in chemistry, in which generally all boxes, tops of tea-canisters, pepper-boxes, teacups, etc., served for the necessary vessels, and the sand-tub furnished the matter to be analysed. I only had to take care to exclude water, which would have produced havoc on my carpet.”
From a preparatory school kept by Dr. Gretton at Hitcham, he was sent, a delicate, blue-eyed lad, to Eton. His mother, however, happening to see him maltreated by a stronger boy, brought him home after a few months, and his education was continued by a Scotch mathematician named Rogers, a man of considerable ability. His pupil held him in high respect; yet, though he learned Euclid accurately from him, he told Dr. Pritchard afterwards that “he knew no more of its real bearing and intention than he knew of the man in the moon.” The results of the home tuition were, none the less, exceedingly brilliant.
Herschel entered St. John’s College, Cambridge, at the age of seventeen, and his aunt noted in her Diary that, from the time of his admittance to the University until he quitted it, he gained all the first prizes without exception. He graduated as Senior Wrangler and First Smith’s Prizeman in 1813, a year in which honours were not cheap. Peacock, subsequently Dean of Ely, took second place, Fearon Fallows, the first Royal Astronomer at the Cape of Good Hope, came third, and Babbage withdrew from the competition, judging himself unable to beat, and not caring to be beaten by Herschel. Rivalry did not disturb their friendship. Having entered, together with Peacock, into a juvenile compact to do what in them lay “to leave the world wiser than they found it,” they, in 1812, set about fulfilling it by the establishment of the “Analytical Society of Cambridge.” Its object was to substitute in England for Newton’s fluxional method the more flexible and powerful calculus in use on the Continent; or, as Babbage expressed it, punning on the required change of notation, “to uphold the principles of pure D-ism in opposition to the Dot-age of the University.” The trio of innovators were full of enthusiasm, and they carried through a reform vital to the progress of British science. Herschel laboured zealously in the cause. In combination with his two allies, he translated Lacroix’s elementary treatise on the Differential Calculus, which became a text-book at Cambridge; and published, in 1820, an admirable volume of “Examples.” “In a very few years,” to use Babbage’s words, “the change from dots to d’s was accomplished; and thus at last the English cultivators of mathematical science, untrammelled by a limited and imperfect system of signs, entered on equal terms into competition with their Continental rivals.” Herschel, writing in the Quarterly Review, playfully described the process by which this was brought about. “The brows of many a Cambridge moderator,” he said, “were elevated, half in ire, half in admiration, at the unusual answers which began to appear in examination-papers. Even moderators are not made of impenetrable stuff; their souls were touched, though fenced with seven-fold Jacquier, and tough bull-hide of Vince and Wood. They were carried away with the stream, in short, or replaced by successors full of their newly acquired powers. The modern analysis was adopted in its largest extent.”
John Herschel was one of Babbage’s “chief and choicest companions,” who breakfasted with him every Sunday after chapel, and discussed, during three or four delightful hours, “all knowable, and many unknowable things.” His life-long friendship with Whewell began after his election to a Fellowship of his College. It lent charm to the occasional residences at Cambridge, which terminated in 1816, on his attaining the dignity of Master of Arts. He celebrated his coming of age at home, and was with his father at Brighton when Campbell characterised him as “a prodigy in science, and fond of poetry, but very unassuming.” His first publication was a paper on “Cotes’s Theorem,” sent, in October, 1812, to the Royal Society, of which body he was chosen a member, May 27, 1813. This was followed by a series of memoirs on various points of analysis, their signal merit being recognised, in 1821, by the bestowal of the Copley Medal. His investigations in pure mathematics were carried no further; but he had done enough to show his power and originality, and materially to widen the scope of the new methods.
He was in no hurry to choose a profession. Evenly balanced inclinations demanded, circumstances indulged delay; so he paused. His father wished him to enter the Church; but he preferred the law, and was enrolled a student at Lincoln’s Inn, January 24, 1814. The step was a simple formality. It committed him to nothing. And, in fact, while nominally reading for the Bar, his thoughts were running in a totally different direction. Dr. Wollaston, whose acquaintance he made in London, fascinated him, and his influence served to steady the helm of his intentions. Having decided finally for a scientific career, he returned to Slough, and plunged into experiments in chemistry and physical optics.
On September 10th, 1816, he informed a correspondent that he was “going, under his father’s direction, to take up star-gazing.” This brief sentence gives the first tidings of an astronomical element in his life. Its growth was slow. He had no instinctive turn that way. It was through filial reverence that he resolved to tread in his father’s footsteps. His self-denial received a magnificent reward. He took a place expressly reserved for him, as it might seem, beside his father as an explorer of the skies on the grandest scale. But for this moral purpose, he might have squandered time in a multiplicity of partial researches. So late as 1830 he told Sir William Rowan Hamilton: “I find it impossible to dwell for very long on one subject, and this renders my pursuit of any branch of science necessarily very desultory.” His nebulæ and double stars saved him from being “everything by turns, and nothing long.” Their collection and revisal, begun as a duty, grew to be irresistibly attractive, and John Herschel pledged himself definitively to astronomy.
His earliest undertaking was the re-examination of his father’s double stars. Entered upon at Slough in 1816, it was continued from 1821 to 1823 at the observatory in Blackman Street, Southwark, of Mr., afterwards Sir James South, where, with two excellent refracting telescopes, of five and seven feet focal length, the colleagues measured 380 of Sir William Herschel’s original pairs. Double stars want a great deal of looking after. Their discovery should be the prelude to long processes of investigation. It is of little interest unless diligently followed up. Each represents a system, individual in its peculiarities, and probably of most complex organisation. The more such systems are studied, the more wonderful they appear. Two associated stars have often proved, on keener scrutiny, to be themselves very closely double; and in other cases, disturbed motion has revealed the existence of obscure masses—planets on a colossal scale, possibly the spacious abodes of unimaginable forms of life.
The “Astronomy of the Invisible,” however, was still in the future when Herschel and South did their work. Facts relating to binary revolutions were scantily forthcoming, and the science to be founded on them had been rather indicated than established. Fresh observations were then needed to ascertain how the circling stars had behaved since 1802. The results proved highly satisfactory. In Francis Baily’s words, “The remarkable phenomena first brought to light by Sir William Herschel were abundantly confirmed, and many new objects pointed out as worthy the attention of future observers.” To take a couple of examples. Eta Coronæ was found to have described, since 1781, one entire round, and to be just starting on a second. Again, Tau Ophiuchi had been perceived, by the elder Herschel, at his first sight of it in April, 1783, to be “elongated.” “One half of the small star,” he said, “if not three-quarters, seems to be behind the large star.” This effect was imperceptible to his son. It had become entirely effaced in the course of forty years. The star was, in 1823, perfectly round; it had, as it were, absorbed its companion. By slow degrees, however, the two came into separate view, and now form an easy telescopic object. Their period of revolution is not less than two centuries. Another point of special interest was the detection of marked eccentricity in a stellar orbit—that of Xi Ursæ Majoris. These stars perform their circuits in just sixty years; but in 1821 their apparent speed was so great that changes in their relative positions could be determined from month to month. For these observations, published with notes and discussions in the Philosophical Transactions for 1824, Herschel and South received the Lalande Prize of the French Academy in 1825, and the Gold Medal of the Astronomical Society in 1826. In the latter distinction, Wilhelm Struve and Amici of Modena were associated with them. These four were the only double star observers then living.