144 Proceedings of Philosophical Societies [Fes. 



prominent lines in the primitive forms ; he has shown that the 

 irregularities observed by M. Biot in sulphate of lime, are the 

 leoitimate and calculable results of its having two axes ; he has 

 established general laws by which the phenomena of the coloured 

 rings, and the phenomena of double refraction, may be calculated 

 with the utmost facility of accuracy for any given number of 

 axes ; he has proved that all the cubical, octohedral, and rhom- 

 boido-dodecahedral crystals have three equal and rectangular axes, 

 which, in general, are in a state of equilibrium ; and he has 

 shown how all the classes of crystals may be artificially imitated 

 during the passage of heat through glass, the two sets of pheno- 

 mena being regulated by the same, laws. The general laws to 

 which Dr. Brewster has been conducted by this laborious inves- 

 tigation, with which he has been occupied more than three years, 

 are not empirical classifications which merely represent the phe- 

 nomena. They are laws rigorously physical, and founded on the 

 principles of mechanics. The polarising forces, and the forces 

 of double refraction, are combined and resolved like all other 

 forces, and the phenomena of polarisation and double refraction 

 can thus be computed with as much accuracy as the motions and 

 positions of the heavenly bodies. In the course of this inquiry 

 a number of new and remarkable properties of light were disco- 

 vered, which the author has promised to communicate to the 

 Royal Society in a series of separate papers. 



Jan. 22. — A paper was read by Sir Everard Home, Bart, con- 

 taining additional facts respecting the fossil remains of an 

 animal, some account of which has already appeared in the Phil. 

 Trans* showing that the bones of the sternum resemble those of 

 the ornithcrhynchus paradoxus. 



The reading of a paper, by Capt. Henry Kater, was begun, 

 containing an account of his experiments for determining the 

 length of the pendulum vibrating seconds in the latitude of London . 



ROYAL SOCIETY OF EDINBURGH. 



Nov. 17. — The Royal Society having resumed their meetings 

 after the summer vacation, the first part of a paper by Dr. Ure of 

 Glasgow was read, containing Experiments and Observations on 

 Muriatic Acid Gas. After giving a condensed view of the pre- 

 sent state of the chloridic controversy, he proceeds to detail a 

 series of experiments, which he had recently executed, for the 

 purpose of deciding this fundamental point of chemical doctrine. 

 Considering the composition of dry sal ammoniac to be definitely 

 fixed by the concurrence of his experimental results, published 

 in the Annals of Philosphy last September, with those of M. Gay 

 Lussac, at 32*24 ammonia 4- 67-76 muriatic acid gas, he ex- 

 posed thin laminae of the pure metals, silver, copper, and iron 

 ignited in green glass tubes out of contact of air, to the action 

 of the vapour of the above dry salt, and found in each case the. 



« For the year 1814. 



\ 



