At Slough, as at Datchet, prevailed the most enthusiastic industry; and the house was soon as full of well-ordered labour as a bee-hive. Smiths were kept constantly at work on different parts of the new telescopic leviathan; and a whole troop of labourers was engaged in grinding the tools required for shaping and polishing its mirror. Had not a cloudy or moonlight night sometimes intervened, Herschel and his sister must have died of sheer exhaustion, for they toiled with unremitting ardour both day and night. With the morning came the workpeople, of whom no fewer than between thirty and forty were at work for upwards of three months together: some employed in felling and rooting out trees, some digging and preparing the ground for the bricklayers, who were laying the foundation for the telescope. Then there were the carpenter and his men; and, meanwhile, the smith was converting a wash-house into a forge, and manufacturing complete sets of tools for his own share of the labour. In short, the place was at one time a complete workshop for the manufacture of optical instruments; and it was a pleasure to enter it for the purpose of observing the fervour of the great astronomer, and the reverent attention given to his orders.
It is impossible not to refer here to the sisterly devotion of Caroline Herschel, who was in every respect worthy of her noble-minded, tender-hearted, and enthusiastic brother.
She stood beside him to the last, sharing his labours, brightening his life. In the days, says her biographer, when Herschel gave up a lucrative career that he might dedicate all his energies to astronomical pursuits, it was through her care and thriftiness that he was spared from the unrest of pecuniary anxieties. As she had been his helper and assistant during his career as a popular musician, so she became his helper and assistant when he gave himself up, like the Chaldeans of old, to the study of the stars. By dint of a resolute will and a love that shrank from no sacrifice or exertion, she acquired such a knowledge of mathematics and calculations, mysterious as these generally seem to the feminine mind, that she was able to formulate with exactness the result of her brother's researches. She never failed to be his willing fellow-labourer in the workshop; she helped him to grind and polish his mirrors; she stood beside his telescope, in order to record his observations, during the dark and bitter mid-winter nights, when the very ink was frozen in the bottle. It may be said, without exaggeration, that she kept him alive by her care: thinking nothing of herself, she lived for him, and him alone. She loved him, she believed in him, she aided him with all her heart and all her strength. Her mental powers were very considerable; and undoubtedly she might have attained to eminence on her own account, for she herself discovered no fewer than eight comets. But she shunned self-glorification; she desired to live in her brother's shadow; she worked for him, never for herself; and in her elevated character no feature more strongly demands our admiration than her heroic though unconscious self-denial. Happy the man who has such a sister; happy the sister whose brother is worthy of so much devotion! It is pleasant to know that William Herschel deserved the love so lavishly poured out at his feet; that great as were his achievements in science, lofty and broad as was his genius, they were fully sustained and ennobled by the beauty and worth of his inner life. Who can contemplate their twofold career in all its singleness of purpose, its purity, its unselfishness, its sublime disregard of worldly pleasures, without emotion? The lessons told by such a life are worth all the moral treatises ever written.