The next great change in the life of the brother and sister took place in 1782, when William Herschel left Bath and was appointed Astronomer-Royal by George the Third. His salary of only £200 a year involved a great loss of income, but this, in his eyes, was a small matter in comparison with the advantage of having his time entirely free to give up to his favourite studies. They bade farewell to Bath, and settled first at Datchet, shortly after, however, removing to Slough. Caroline had dismal visions of bankruptcy, but William was in the highest spirits, and declared that they would live on eggs and bacon, “which would cost nothing to speak of, now that they were really in the country.”
Caroline was now installed as an assistant astronomer, and was given a telescope, which she calls a “seven-foot Newtonian Sweeper”; and she was instructed, whenever she had an evening not in attendance on her brother, to “sweep for comets”; but her principal business appears, at this time, to have been waiting on her brother, and writing down the results of his observations; they worked quite as hard as they had done at Bath. They laboured at the manufacture of instruments all day, and at the observation of the heavens all night. No severity of weather, if the sky was clear, ever kept them from their posts. The ink often froze with which Caroline was writing down the results of her brother’s observations. It has been well said that if it had not been for occasional cloudy nights, they must have died of overwork. The apparatus for erecting the great forty-foot telescope, and the iron and woodwork for its various motions, were all designed by William Herschel, and fixed under his immediate direction. His sister, in her Recollections, wrote: “I have seen him stretched many an hour in the burning sun across the top beam, whilst the iron-work for the various motions was being fixed.” The penurious salary granted to William Herschel was supplemented by special grants for the removal and the erection of all this machinery; and in 1787 Caroline’s services to her brother were publicly recognised by her receiving the appointment of assistant to her brother at a salary of £50 a year. She was at all times grateful to members of the royal family for acts of kindness shown by them to her brother and herself; but it is evident that she felt that, so far as money was concerned, she had not much cause for gratitude to the royal bounty. She points out that at the time when Parliament was granting George III. the sum of £80,000 a year for encouraging science, £200 was considered a sufficient salary for the first astronomer of the day; and yet money could flow liberally enough in some directions, for £30,000 was at that time being spent on the altar-piece of St. George’s Chapel, Windsor. Even Caroline’s little salary of £50 a year was not regularly paid. It was a trial to her again to become a pensioner on her brother’s purse, and it was not till nine quarters of her official salary remained unpaid, that she reluctantly applied to him for help. No wonder that in reading, after her brother’s death, an account of his life and its achievements, she remarks, “The favours of monarchs ought to have been mentioned, but once would have been enough.”
It was after her brother’s marriage, in 1788, that the majority of Caroline’s astronomical discoveries were made. She discovered her first comet in 1786, her eighth and last in 1797. She was recognised as a comrade by all the leading astronomers of Europe, and received many letters complimenting her on her discoveries. One from De la Lande addressed her as “Savante Miss,” while another from the Rev. Dr. Maskelyne saluted her as “My worthy sister in astronomy.” Royal and other distinguished visitors constantly visited the wonderful forty-foot telescope at Slough, and either William Herschel or his sister were required to be in attendance to explain its marvels. The Prince of Orange, on one occasion, called, and left an extraordinary message “to ask Mr. Herschel, or if he was not at home, Miss Herschel, if it was true that Mr. Herschel had discovered a new star, whose light was not as that of the common stars, but with swallow-tails, as stars in embroidery.” The only glimpse we get, through the peaceful labours of Caroline’s long life, of the strife and turmoil of the French Revolution, is the note she makes of the visit, to her brother’s observatory, of the Princesse de Lamballe. “About a fortnight after this,” the diarist observes, “her head was off.” The absence of all comment upon the wonderful political events of the time is noticeable, and so also is Caroline’s thinly-veiled contempt for any science less sublime than that to which she and her brother were devoted. Her youngest brother, Dietrich, was a student of the insect world. “He amuses himself with insects,” she wrote to her nephew; “it is well he does not see the word amuses, for whenever he catches a fly with a leg more than usual, he says it is as good as catching a comet.” Her brother’s marriage, though far from welcome at the time it took place, was a great blessing to her; for it gave her a most tender and affectionate sister, and ultimately a nephew, the inheritor of his father’s great gifts, and the being to whom, after William Herschel’s death in 1822, Caroline transferred all the devoted and passionate attachment of which her nature was capable.
The great mistake of her life was going back to Germany after Sir W. Herschel’s death in 1822. She was then seventy-two years of age, and the previous fifty years of her life, containing all her most precious memories and associations, had been spent in England. In this country, also, were all those who were dearest to her. Yet, no sooner was her brother dead, than she felt life in England to be an impossibility. She little thought that she had still twenty-six years to live; indeed she had long been under the impression that her end was near, but while her brother lived she kept this to herself, because she wished to be useful to him as long as she possibly could. She never really re-acclimatised herself to Germany. “Why did I leave happy England?” she often said. The one German institution she thoroughly enjoyed was the winter series of concerts and operas, which she constantly attended, and she mentions with pleasure, in her letters, that she was “always sure to be noticed by the Duke of Cambridge as his countrywoman, and that is what I want; I will be no Hanoverian.” She laments the death of William IV., chiefly because, by causing a separation of the crowns of England and Hanover, it seemed to break a link between herself and the country of her adoption.
She never revisited England, but she kept up a constant communication with it by letters to her sister-in-law, her nephew, and later to her niece, Sir John Herschel’s wife. At that time the post between London and Hanover was an affair of fifteen days, and letters were carried by a monthly messenger, of whose services she seldom failed to avail herself. She took the keenest interest in her nephew’s distinguished career. His letters to her are full of astronomy. In 1832 he made a voyage to the Cape to observe the stars in the Southern Hemisphere. When Miss Herschel first heard of the intended voyage she refused to believe it. But when she was really convinced of it, the old impulse was as strong upon her as upon a war-horse who hears the trumpet. “Ja! if I was thirty or forty years younger and could go too!” she exclaimed.
On 1st January 1840 the tube of the celebrated forty-foot telescope was closed with a sort of family celebration. A requiem, composed by Sir John Herschel for the occasion, was chanted, and he and Lady Herschel, with their seven children and some old servants, walked in procession round it, singing as they went. On hearing of this from Slough, Miss Herschel recalls that the famous telescope had also been inaugurated with music. “God save the King” had then been sung in it, the whole company from the dinner-table mounting into the tube, and taking any musical instruments they could get hold of, to form a band and orchestra.
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