amination showed that it was moving at the rate of two and a half seconds per hour. It was the planet now called Uranus. Herschel had commenced his career by a discovery which raised him to the front rank of astronomers. Continental observers wished to confer on the new planet the name of its discoverer, and the symbol by which it is known in astronomy, still bears his initial. But after an interval, during which it was called by Herschel's proposed name of the "Georgium Sidus," it was christened "Uranus"—now its recognized appellation. Uranus had often been seen before; indeed, it was observed and recorded on no less than twenty previous occasions as a fixed star. Arago[1] points out that "if Herschel had directed his telescope to the constellation Gemini eleven days earlier (that is, on March 2 instead of March 13) the proper motion of Uranus would have escaped his observation, for on the 2nd the planet was in one of its stationary points. It will be seen from this remark on what may depend the greatest discoveries in astronomy." One step in this fascinating science inevitably leads to another. Perturbations in the course of Uranus led Adams, in England, and Leverrier, in France, to suspect the existence of yet another planet, whose attraction should be sufficiently powerful to alter the path of Uranus through space, and yet so distant as to have eluded observers since the beginning of the world. The event proved that they were right, and Neptune was discovered by the Prussian astronomer Dr. Galle in the very spot indicated by the two great astronomers; who thus achieved probably the greatest triumph ever won by mathematical science.[2]
The fame of Herschel's discovery spread rapidly. The most prominent astronomers made the journey to Bath—no ordinary undertaking in those days—to see the great telescopes at which he was labouring with extraordinary assiduity[3] and to converse with their inventor. Miss Herschel's journals are filled with accounts of preparations for new oratorios and the making of new telescopes in almost equal proportions. The casting of a mirror for one of the instruments well-nigh proved fatal to all the adventurers. The metal was in the furnace, which unfortunately began to leak at the moment when ready for pouring. "Both my brothers," says Miss Herschel, "and the caster with his men, were obliged to run out at opposite doors, for the stone flooring flew about in all directions as high as the ceiling. My poor brother fell exhausted with heat and exertion on a heap of brickbats." A second casting resulted in a very perfect metal. While he was thus busily engaged, the king invited him to Windsor, and desired him to bring his instruments with him.
After this visit, Herschel never returned permanently to Bath; he was caressed and honoured by all the savants of the metropolis, and the king was so interested by the extraordinary objects in the starry heavens which were shown to him, that he invited the Bath musician to become his private astronomer, with a salary of 200l. per annum. In such notices of Sir William Herschel's life as have been published, it has been assumed that the king provided for his astronomer with royal munificence, M. Arago adopts the current story. Such, however, was not the case. The income of Sir William Herschel at Bath, from his organist's salary and his musical pupils, very greatly exceeded that which he accepted at the hands of his royal patron. Miss Herschel speaks, in one of her latest letters[4] of the life of privations and struggles undergone by her brother—she says nothing of her own—during between twenty and thirty years, till he had realized a sufficient capital for living respectably by the making of seven, ten, twenty, and twenty-five feet telescopes. She also mentions that it was at first intended, when M. de Mainborg, who had formerly been one of the king's tutors, and was afterwards his private astronomer, died, to make Sir William Herschel astronomer at Kew in his room. But it was otherwise determined, for "the king was surrounded by some wiseacres who knew how to bargain, and even offered 100l if he would go to Hanover."
A house was taken at Datchet, in which Miss Herschel was promptly installed as housekeeper and general assistant. The new home was a large neglected place,
- ↑ Quoted in Chambers's "Astronomy," p. 150.
- ↑ Alexander Humboldt wrote to Miss Herschel on the 25th September, 1846, a letter conveying to her from the king of Prussia the gold medal for science, on the occasion of her ninety-sixth birthday. "I know I may count upon your indulgence. . . . I specially deserve such leniency to-day—the day on which my young friend Dr. Galle, assistant astronomer in our observatory (to the triumph of theoretical astronomy be it said), has discovered the trans-Uranian planet indicated by Leverrier as the cause of the perturbations of Uranus."
- ↑ "Même à l'époque où, dans la ville de Bath, Herschel n'était qu'un simple amateur d'astronomie, il fit jusqu' à deux cents miroirs newtoniens de 7 pieds anglais de foyer; jusqu' à cent cinquante miroirs de 10 pieds, et environ quatre-vingts miroirs de 20 pieds."
- ↑ Hanover, Feburary, 1842.
