xx Address of Mr J. W. Clark, President, 



COMMUNICATIONS MADE TO THE SOCIETY. 



February 20, 1820 K 



By Professor Farish (President) : On Isometrical Perspective. 



By Prof. E. D. Clarke : On the discovery of Cadmium in some of the English 



ores of zinc; with some directions respecting the mode of operating. 

 By Captain Fairfax (presented hy Mr Okes) : On Soundings at Sea. 



March 6, 1820. 



By Joh. Hailstone, M.A. (Trin.) : On the probable origin of a fossil body found 



on the coast of Scarborough. 

 By Professor Farish (President): On Isometrical Perspective (concluded). 



Trans. I. 1 — 19. 

 By Joh. Fre. Will. Herschel, M.A. (Joh.) : On functional equations. Trans. I. 



77—87. 

 By Mr Okes: On some fossil remains of the Beaver, found near Chatteris. 



Trans. I. 175—177. 



March 20, 1820. 



By Professor Sedgwick : On the Geology of Cornwall, etc. 

 By Mr Thompson (Joh.) : A translation from Gemmellaro's account of the 

 last great eruption of Etna, in 1819. (Presented by Dr E. D. Clarke.) 



April 17, 1820. 



A letter from the Rev. J. Davis to the Rev. Dr Wood, detailing certain 

 optical phenomena observed at Hilkhampton in Cornwall on Wednesday, 

 April 5th, 1820, was read to the Society. 



By Joh. Fre. Will. Herschel, M.A. (Joh.) : On the rotation impressed by 

 plates of rock crystal on the planes of polarization of the rays of light as 

 connected with certain peculiarities in its crystallization. Trans, i. 43 — 

 52. 



By Will. Whewell, M.A. (Trin.) : On the position of the apsides of orbits of 

 great eccentricity. Trans. I. 179 — 191. 



May 1, 1820. 



By Professor Farish (President) : On the mode of conducting Polar navigation. 

 By Joh. Fre. Will. Herschel, M.A. (Joh.) : On certain remarkable instances of 



deviation from Newton's scale in the tints developed by crystals with an 



axis of double refraction on exposure to polarized light. Trans. I. 21 — 



41. 

 By Ch. Babbage, M.A. (Trin) : On the Calculus of Functions. Trans. I. 63— 



76. 



May 15, 1820. 



By Mr Emmett : Researches into the mathematical principles of chemical 

 philosophy. 



By Prof. E. D. Clarke : On the chemical constituents of the purple precipitate 

 of Cassius. Trans. I. 53 — 61. 



By Professor Sedgwick : On the physical structure of Cornwall, etc. (con- 

 tinued from 23 March). Trans. I. 89 — 146. 



1 The Minute Book says : " Monday, February 21, 1820 "; but in 1820 February 

 21 fell on a Tuesday. 



