This incident took place in the winter of 1775, at a house situated near Walcot turnpike, to which Herschel had removed in the summer of the previous year. Here, on a grass plot behind the house, he made active preparations for the erection of a twenty-foot telescope. So assiduous was his devotion to this work, that while he was engaged in polishing the mirror, his sister was constantly obliged to feed him by putting his victuals into his mouth. Otherwise he would have reduced himself to a condition of positive emaciation! Once, when finishing a seven-foot mirror, he did not take his hands from it for sixteen consecutive hours; for in these days machinery had not been devised as a substitute for manual toil. He was seldom unemployed at meals; but at such times employed himself in contriving or making drawings of whatever occurred to his fertile fancy. Usually his sister Caroline read to him while he was engaged at the turning-lathe, or polishing mirrors; choosing such books as "Don Quixote," the "Arabian Nights," the novels of Sterne and Fielding; and tea and supper were served without any interruption to the task in which Herschel was absorbed.
In Miss Herschel's charming letters we find a vivid sketch of the family avocations at this period:–
"My brother applied himself to perfect his mirrors, erecting in his garden a stand for his twenty-foot telescope: many trials were necessary before the required motions for such an unwieldy machine could be contrived. Many attempts were made by way of experiment against a mirror before an intended thirty-foot telescope could be completed, for which, between whiles (not interrupting the observations with seven, ten, and twenty-foot, and writing papers for both the Royal and Bath Philosophical Societies), gauges, shapes, weights, &c., of the mirror were calculated, and trials of the composition of the metal were made. In short, I saw nothing else and heard nothing else talked of but about these things when my brothers were together. Alex was always very alert, assisting when anything new was going forward; but he wanted perseverance, and never liked to confine himself at home for many hours together. And so it happened that my brother William was obliged to make trial of my abilities in copying for him catalogues, tables, &c, and sometimes whole papers which were lent [to] him for his perusal. Among them was one by Mr. Michel, and a catalogue of Christian Mayer in Latin, which kept me employed when my brother was at the telescope at night. When I found that a hand was sometimes wanted when any particular measures were to be made with the lamp micrometer, or a fire to be kept up, or a dish of coffee necessary during a night's long watching, I undertook with pleasure what others might have thought a hardship."
The astronomer-musician's patient survey of the heavens was rewarded, on the 13th of March 1781, by the discovery of a new planet, situated on the borders of our Solar System. In every way this was a discovery of signal importance. It broke up the traditional conservatism of astronomers, which had almost refused to regard as possible the existence of any planets beyond the orbit of Saturn, because for so many years none had revealed themselves to the watchful gaze. Men's minds were widened, so to speak, at a bound; their conceptions strengthened and enlarged; for the discovery of Georgium Sidus—as the new planet was designated by its discoverer, in honour of George III.—rendered possible and probable the discovery of other planets, and thus extended immeasurably the limits of the Solar System. Herschel, whose reputation as a musician had hitherto been local, now sprang into world-wide fame as an astronomer. George III., who was a true lover of science, and not disinclined to bestow his patronage on men and things of Hanoverian origin, summoned him to his presence; and was so much pleased with his modest and interesting account of the long labours which had led to the great result, that, after a brief interval, he bestowed upon him an annual pension of three hundred guineas, and a residence, first at Clay Hall, and then at Slough.
But before this well-deserved good fortune fell to him, Herschel continued his industrious career as both musician and astronomer. During the concert season, which lasted five or six months, he had never a night disengaged, but was conducting oratorios at Bath or Bristol, arranging for public concerts, attending rehearsals, and superintending the performances of his choir. As soon as a lull came, the indomitable man, assisted by his faithful sister, returned to his astronomical pursuits. To gain a fuller and clearer knowledge of the starry worlds scattered over the vast fields of space, Herschel from the first had seen that instruments of much greater power were necessary than any hitherto used by astronomers. He set to work, therefore, on the construction of a thirty-foot telescope; the metallic mirror of which must, of course, be of proportionate dimensions. This huge mirror was to be cast in a mould of loam prepared from horse-dung, of which an immense quantity was to be pounded in a mortar, and sifted through a fine sieve; an arduous and almost endless task, undertaken by Caroline Herschel and her brother Alex. Then a furnace was erected in a back-room on the ground-floor; and every preparation having been made, a day was set apart for the casting. The day came, and Herschel and his collaborateurs looked forward to the consummation of their hopes. The metal was placed in the furnace; but, unfortunately, just when it was ready for pouring in a molten stream into the mould, it began to leak, and both the Herschels, and the caster with his men, were compelled to fly from the apartment, the stone flooring exploding, and flying about in all directions, as high as the ceiling. The astronomer, exhausted with heat and exertion, fell on a heap of brickbats; exhausted, but not dismayed. The work was renewed; and a second casting being attempted, it proved entirely successful, and a very perfect metal was formed in the mould.
CHAPTER III
In August 1782 the Herschels removed to Datchet. Their new home was "a large neglected place; the house in a deplorably ruinous condition, the garden and grounds overgrown with weeds." Nor were the domestic arrangements more favourable. For a fortnight the little family were without a female servant; and an old woman, the gardener's wife, showed Miss Herschel the shops, where the high prices of every article, from coals to butcher's meat, appalled her. But of these inconveniences Herschel took no account. Enough for him that he was released from the drudgery of teaching, and free thenceforth to devote himself to the heavens and their wonders. A man whose thoughts are always with the stars can hardly be expected to trouble himself about the price of tallow-candles! Were there not capacious stables in which mirrors of any size could be ground; and a roomy laundry capable of easy conversion into a library, with one door opening on a large lawn, where the "small twenty-foot" was to take its stand? Compared with advantages such as these, what mattered the scarcity of "butcher's meat"? Herschel laughingly assured his sister that they could live on eggs and bacon; which, he confidently asserted, would cost next to nothing, now that they were really in the country!
And so he settled down to a life of quiet, industry at Datchet; his admirable sister being formally adopted as his assistant and secretary. Never had master a more devoted, a more enthusiastic, or a more intelligent servant! She shared in all his night-watches, with her eye constantly on the clock, and the pencil in her hand; with unerring accuracy she made all the complex calculations so frequently required; she made three or four copies of every observation in separate registers, co-ordinating, classifying, and analyzing them. If the scientific world, says Arago, saw with astonishment the unexampled rapidity with which Herschel's works succeeded one another for many years, they were greatly indebted for this affluence of production to the affectionate ardour of his sister Caroline. Her enthusiasm never failed; her industry knew no check; and her brother's fame was dearer to her than life.
In one of her letters she describes with graphic simplicity the "interior" at Datchet:—
"I found that I was to be trained for an assistant-astronomer; and by way of encouragement, a telescope adapted for 'sweeping' (or rapidly surveying a wide extent of space), consisting of a tube with two glasses, was given [to] me. I was to 'sweep for comets;' and I see by my journal that I began August 22nd, 1782, to write down and describe all remarkable appearances I saw in my 'sweeps.' But it was not till the last two months of the same year that I felt the least encouragement to spend the starlit nights on a grass-plot covered with dew or hoar-frost, without a human being near enough to be within call. I knew too little of the real heavens to