CONTENTS. 
VIII. Observations on the two lately discovered celestial Bodies. 
By William Herschel, LL. D. F. R. S. p. 213 
IX. Description of the Corundum Stone , and its Varieties , com- 
monly known by the Names of Oriental Ruby, Sapphire, &c. ; 
with Observations on some other mineral Substances. By the 
Count de Bournon, F. R. S. p. 233 
X. Analysis of Corundum, and of some of the Substances which 
accompany it; with Observations on the Affinities which the 
Earths have been supposed to have for each other, in the humid 
Way. By Richard Chenevix, Esq. F. R. S. and M. R. I. A. 
P* 327 
XI. Description of the Anatomy of the Ornithorhynchus Hystrix. 
By Everard Home, Esq. F. R. S . p. 348 
XII. A Method of examining refractive and dispersive Powers , 
by prismatic Reflection. By William Hyde Wollaston, M. D. 
F. R. S. p. 365 
XIII. On the oblique Refraction of Iceland Crystal. By William 
Hyde Wollaston, M. D. F. R . S. p. 381 
XIV. An Account of some Cases of the Production of Colours, not 
hitherto described. By Thomas Young, M. D. F. R. S. 
F. L. S. Professor of Natural Philosophy in the Royal Insti- 
tution. p # 387 
XV. On the Composition of Emery. By Smithson Tennant, 
Esq. F„ R » S. p, 3^8 
