1840-50] ROYAL ASTRONOMICAL SOCIETY 107 eclipse would be total for a brief space at an accessible point near Tellicherry, on the coast, he proceeded there with his instruments, ascended a river to its source and partly surveyed it. He obtained his observations. In the case of comets, especially the great comet of 1843, observations of varied rank and value flowed in by correspondence from all quarters of the world, and were recorded by the Society. Foreign Astronomers. Foreign astronomers made hardly less use of the Society for announcements. Schumacher, in particular, was indefatigable in sending ephemerides and other news of interest. And in return, when the troubles of 1848 brought Schumacher's position at Altona into jeopardy, arising from a rebellion in the Duchies of Slesvig and Holstein against the King of Denmark, all the astronomers of Europe used what influence they had to support him ; the Society sent a deputation to Lord Palmerston, by whom it was sympathetically received, and the case immedi- ately represented to the Danish Government. Instrumental Advances. The interest of the Society in instru- mental advances was keen, and with few exceptions the lines approved have stood the test of experience. In 1843, Simms described his new dividing engine, which was self-acting. Airy successively described his plans for the new transit circle, the reflex zenith tube, and the chronograph. He also described with care and fulness the methods of casting and grinding specula, of Lord Rosse and of Lassell. Lord Rosse contributes some interesting remarks on the mounting of a great mirror, which are still to the point. Lassell was a frequent contributor as well as an indefatigable observer, and his 24-inch speculum, with its equatoreal mounting, must have been an unusually fine piece of work, as evidenced by the discovery of Hyperion, of two of the lost satellites of Uranus, and of the satellite of Neptune. Some of the subjects talked about seem to us strangely familiar, though at the time they were mere talk ; for example, " The advantage of large specula and elevated posi- tions," by Piazzi Smyth. The Neilgherry Hills was the site he suggested, that is to say, not so far from the site of Kodaikanal. Equally assiduous were Fellows in studying improvements in methods of using the instruments and the minutiae of reading upon which refinements depend. Sheepshanks was one of the most expert. The many entries regarding the standard yard offer an illustration. The Society possessed, and still possesses, a copy of the national standard. The original was destroyed in the con- flagration at the Houses of Parliament in 1834, and at the request of the Government the Society's copy was lent for the purpose of constructing by comparison a new standard. The work went on slowly ; all the difficulties of this branch of metrology had to
