11 
CONTENTS. 
Art. IX. Account of the Descent of the Glacier of the Weiss- 
horn, on the 27th December 1819^ and the De- 
struction of the Village of Randa, ” 274 
X. Historical Account of Discoveries respecting the 
Double Refraction and Polarisation of Light. Con- 
tinued from Vol. III.p. 154. - 277 
Period II. Containing an Account of Huygens’ 
Theory of Double Refraction. Concluded from 
Vol. III. p. 154, - - ib. 
XI. On the Temperature of the different Mines in Ame- 
rica. By Baron Alexander de Humboldt, 286 
XII. On the Ellipticity of the Earth. By William Watts, 
Esq. Communicated by the Author, - 288 
XIII. Account of the Family of Sir Isaac Newton, in a 
Letter from the late Thomas Reid, D. D. Professor 
of Moral Philosophy, Glasgow, to the late John 
Robison, LL. D. F. R. S. Ed. Professor of Natural 
Philosophy in the University of Edinburgh, - 29^ 
XIV. Remarks on the Comparative Number of the Sexes at 
Birth. By M. Hufeland of Berlin, - 296 
XV. History of Chemical Discoveries, - 299 
1. On the Conversion of Animal Matter into new 
Substances by Sulphuric Acid. By H. Bra- 
connot, - - - ib. 
2. On the Caloric of a Vacuum. By M. Gay Lussac, SOI 
3. Observations on Oily Substances, By M. Theo- 
dore de Saussure, - - S02 
4. Account of Brucine, a new Vegetable Alkali, SOS 
5. Account of Delphine, a new Vegetable Alkali, S05 
6. New Vegetable Principle in Elaterium> S07 
7. Observations on the Red Snow of Mount St 
Bernard. By M, Peschier, - 307 
8. Experiments on the Alloys of Steel. By J. 
Stodart, Esq. and M. Faraday, - 308 
9. Chemical Analyses, - - 313 
10. On the Existence of Cantharidin in the Lytta 
vittata, or Potato Fly, By J. F. Dana, M.D. 315 
11. Reference to Chemical Memoirs in Foreign 
Journals, &c. - - - 316 
XVI. Outline of Professor Mohs’ New System of Crystallo- 
graphy and Mineralogy. Continued from p. 176. SI 7 
