81 



the beauty of the polish. I may add, that for attaining a true para- 

 bolic figure in the grinding, Mr Lassell employs a beautiful mechan- 

 ism of his own invention, which is put in motion by a small one- 

 horse-power steam-engine. The powers which he uses with this 

 fine instrument, are, — 



For planets, from 300 to 800. 



For fixed stars, from 600 to 1200. 



For double and triple stars, from 1200 to 1800. 



The following Donations to the Library were announced : — 



Natuurkundige Verhandelingen van de Hollandsche Maatschappij 

 der Wetenschapen te Haarlem. Tweede Versameling, 7 Deel, 

 4to. — From the Society. 



An Essay Explanatory of the Tempest Prognosticator, in the build- 

 ing of the Great Exhibition for the Works of Industry of all 

 Nations. By George Merryweather, M.D. 8vo. — From the 

 Author, 



Letters to a Candid Inquirer on Animal Magnetism. By W. Gre- 

 gory, M.D. 12mo. — From the Author. 



Flora Batava. 165 Aflevering. 4to. — From the King of Holland, 



Astronomical Observations made at the Radcliffe Observatory, 

 Oxford, in the year 1848. By M. J. Johnson. Vol. IX. 

 8vo. — From the Radcliffe Trustees. 



Astronomical Observations made at the Radcliffe Observatory, 

 Oxford, in the year 1849. By M. J. Johnson. Vol. X. 8vo. 

 — From the Radcliffe Trustees. 



Proceedings of the Zoological Society of London, 1835, 1836, 1837, 

 1838, 1840, 1841, 1844, 1845, 1846. 8vo.--i^rom the 

 Society. 



Reduction of the Observations of Planets, made at the Royal 

 Observatory, Greenwich, from 1750 to 1830, under the Super- 

 intendence of G. B. Airy, Esq. 4to. 



Reduction of the Observations of the Moon, made at the Royal 

 Observatory, Greenwich, from 1750 to 1830, under the 

 Superintendence of G. B. Airy, Esq. 2 vols. 4to. 



Catalogue of 2156 Stars, formed from the Observations made during 

 the twelve years from 1836 to 1847, at the Royal Observatory, 

 Greenwich. 4to. 



