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.

To Miss Herschel's diary we again refer, for a glimpse of the occupations of her brother and herself at Slough in the first two years of their residence. These two years, to use an apt expression of her own, were spent in a perfect chaos of business. The garden and workrooms swarmed with labourers and workmen—smiths and carpenters speeding to and fro between the forge and the forty-foot machinery; and so incessant was the vigilance of Herschel, that not a screw-bolt in the whole apparatus was fixed except under his eye. "I have seen him," writes his sister, "lying stretched many an hour in the burning sun, across the top beam, whilst the iron-work for the various motions [of the great telescope] was being fixed." At one time no fewer than twenty-four men, in relays of twelve each, were engaged in grinding and polishing day and night; and Herschel never left them, taking his food without allowing himself time to sit down to table.

In recognition of his scientific triumphs, the honorary degree of LL.D was conferred upon Herschel, in 1786, by the University of Oxford. They were triumphs that well merited such a recognition. He had already made some important observations on the nature of double stars, on the dimensions of the telescopic planets, and had begun his famous investigations into the composition of the nebulae,—those clusters of stars and nebulous matter which had previously proved such a problem to astronomers. The remarkable phenomenon of a periodical change of intensity in certain stars, which wax and wane in radiance like a revolving light, had also excited his attention. Further, he had entered upon the experiments which ultimately showed that the Sun positively moves; that in this, as in other respects, the magnificent orb of day must be ranged among the stars; that the apparently inextricable irregularities of numerous sidereal proper motions arise in great part from the displacement of the Solar System; that, in short, the point of space toward which Earth and its sister planets are annually advancing, is situated in the constellation of Hercules.

"Let us," says a French writer, "to these immortal labours add the ingenious ideas that we owe to Herschel on the nebulae, on the constitution of the Milky Way, on the Universe as a whole,—ideas which almost by themselves constitute the actual history of the formation of the worlds,—and we cannot but have a deep reverence for that powerful genius that scarcely ever erred, notwithstanding the ardour of its imagination."

The ordinary spectator, looking upon the face of the heavens through a telescope, had, prior to Herschel's time, felt his curiosity excited by the appearance here and there of filmy patches, vague in structure and irregular in shape, which, from their resemblance to clouds, received the name of nebulae. What these were, no astronomer had succeeded in defining. It was left for Herschel, with his rare powers of patient and discriminating observation, assisted by the more powerful instruments which his ingenuity succeeded in constructing, to discern in them innumerable groups of worlds, in various stages of formation! A new light was thrown upon the history of the Universe. Man was able to assist, as it were, at the process of creation, and to watch the development of a mass of incoherent matter into a perfect star. This alone was a discovery which