Dr. Whewell vainly tried to inveigle him, in November, 1838, into accepting the presidentship of the Geological Society; but he had to submit, in 1842, to be elected Rector of Marischal College, Aberdeen; and he consented to preside over the meeting of the British Association at Cambridge in June, 1845. His dignity on the occasion was not allowed to interfere with his usefulness. He wrote home June 22: “We have been on the Magnetic Committee working hard all the morning, in a Babel of languages and a Babylonian confusion of ideas, which crystallised into something like distinctness at last.” By that time the long-desired particulars regarding terrestrial magnetism were rapidly accumulating. Facts, as Herschel announced from the Presidential Chair, were plentifully at hand. “What we now want is thought, steadily directed to single objects, with a determination to avoid the besetting evil of our age—the temptation to squander and dilute it upon a thousand different lines of inquiry.”
Herschel observed the great comet of 1843 from the roof of his house at Collingwood, on March 17, the first evening of its visibility in England. All that could be seen was “a perfectly straight narrow band of considerably bright, white cloud, thirty degrees in length, and about one and a half in breadth.” It was not until the following night that he recognised in this strange “luminous appearance” “the tail of a magnificent comet, whose head at the times of both observations was below the horizon.”
In December, 1850, he was appointed Master of the Mint—a position rendered especially appropriate to him by Newton’s prior occupation of it. The duties connected with it were just then peculiarly onerous. Previously of a temporary and political character, the office now became permanent, and simply administrative. Many other changes accompanied this fundamental one. “The whole concern,” he said, “is in process of reorganisation.” This fresh start demanded much “personal and anxious attendance.” Notwithstanding his anxious regard for the interests of subordinates, the reconstruction could not but be attended by serious friction. No amount of oiling will get rusty wheels to revolve smoothly all at once. “Things progress rather grumpily,” he reported privately, “owing to the extreme discontent of some parties.” Further contentious business devolved upon him as a member of the jury on scientific instruments at the Great Exhibition. His time was fully and not agreeably occupied. Rising at six, he worked at home until half-past nine, then hurried to the Mint, which he exchanged between three and four o’clock for the Exhibition, and there, until the closing of its doors, examined the claims, and appeased the quarrels of rival candidates for distinction. He also sat on the Royal Commission appointed in 1850 to inquire into the University system. Its recommendations, agreed to by him in 1855, greatly disgusted Whewell; but their friendship remained unaltered by this discordance of opinion.
These accumulated responsibilities were too much for Herschel’s sensitive nature; and the burthen was made heavier by a partial separation from his family. He was never alone in Harley Street, but the joyous life of Collingwood could not be transported thither; and the arid aspect of a vast metropolis, suggesting business and pleasure in excess, but little of enjoyment in either, oppressed him continually. His health suffered, and in 1855 he withdrew definitively into private life. His resignation of the Mint was most reluctantly accepted.
“I find,” playfully remarked De Morgan, “that Newton and Herschel added each one coin to the list: Newton, the gold quarter-guinea, which was in circulation until towards the end of the century; Herschel, the gold quarter-sovereign, which was never circulated.”
It was not the repose of inaction that Herschel sought at Collingwood. “Every day of his long and happy life,” Professor Tait said truly, “added its share to his scientific services.” Thenceforward he devoted himself chiefly to the formidable task of collecting and revising his father’s results and his own. His “General Catalogue of Nebulæ,” published in the Philosophical Transactions for 1864, was in itself a vast undertaking. It comprised 5,079 nebulæ and clusters, to which it served as a universal index of reference. It averted the mischief of duplicate discoveries, settled the sidereal status of many a pseudo-comet, and quickly became the authoritative guide of both comet- and nebula-hunters. In the enlarged form given to it by Dr. Dreyer in 1888, it is likely long to hold its place. Herschel next, in 1867, amalgamated into a regular catalogue of 812 entries his father’s various classed lists of double stars (Memoirs, Royal Astronomical Society, xxxv.). A far more comprehensive work was then taken in hand. He desired to do for double stars what he had done for nebulæ—to compile an exhaustive register of them in the shape of a catalogue, accompanied by a short descriptive account of each pair. But he was not destined to put this coping-stone to the noble monument erected by his genius. Strength failed him to digest and dispose the immense mass of materials he had collected. Nor was it possible for another to gather up the loose threads of his unfinished scheme. All that could be done was to preserve the imposing fragment as he left it. An ordered list of the 10,320 multiple stars he had proposed to treat was accordingly published in the fortieth volume of the same Society’s Memoirs under the care of Professor Pritchard and Mr. Main. But it hardly possesses more than a commemorative value.
Maria Edgeworth was an old friend of Sir John Herschel’s. In March, 1831, she paid him a three days’ visit at Slough, which, she told a friend in Ireland, “has far surpassed my expectations, raised as they were, and warm from the fresh enthusiasm kindled by his last work” (the “Preliminary Discourse”). Mrs. Herschel she described as “very pretty,” sensible, and sympathetic, and possessed of the art of making guests happy without effort. On Sunday, after service, the philosopher showed off the dazzling colour-effects of polarised light, and at night, with the twenty-foot, “Saturn and his rings, and the moon and her volcanoes.”
After twelve years, she came again, this time to Collingwood. “I should have written before,” Herschel assured Sir William Hamilton, December 1st, 1843, “but Miss Edgeworth has been here, and that, among all people who know how to enjoy her, is always considered an excellent reason for letting correspondence and all other worldly things ‘gang their ain gate.’ She is more truly admirable now, I think, than at any former time, though in her seventy-fifth year.”
Maria herself wrote from Collingwood in the following spring: “Here are Lord and Lady Adare, Sir Edward Ryan, and ‘Jones on Rent.’ Jones and Herschel are very fond of one another, always differing, but always agreeing to differ, like Malthus and Ricardo.”
Sir William Hamilton spent a week under the same hospitable roof in 1846. He was delighted, and, as was his wont, compressed the expression of his pleasure “within the Sonnet’s scanty plot of ground.” In the first of a pair entitled “Recollections of Collingwood,” he celebrated the “thoughtful walk” with his host, and the “social hours” in a family circle,