146 Royal Societij. 



A small vuluiiie upon the Art of makings managing, flavour- 

 ing, colouring, preserving, and recovering all Kinds of Wines, 

 Spirits, and Compounds, with Directions for Brewing, &;c. by 

 M. R. Westney, will be published in a few days. 



XXXVIII. Proceedmg'i of Learned Societies. 



ROYAL SOCIETY. 



Feb. 6. X HE President in the chair. A paper by Ed. Davy, 

 Esq. Professor of Chemistry at the Cork Institution, was read, 

 relating his discovery of a fulminating platinum. Thin plates of 

 platinum were dissolved in nitro-muriatic acid, the solution eva- 

 porated to drvness, and afterwards boiled with ])otash and ammo- 

 nia, in nearly the same manner as the aurum fuhiiinans is prepared, 

 when the autlior found a gray powder which explodes violently 

 on exposure to heat. On its explosive powers iSIr. Davy made 

 a great variety of experiments, and also to ascertain with pre- 

 cision its real nature and constitution. On heating the gray 

 powder with lime in a retort, ammonia and water were produced ; 

 one grain yielded O'i 5 cubic inch of nitrogen gas ; but it ap- 

 peared that, in consequence of the formation of water, about 

 0'03 of this gas had been absorbed. 



Feb. 13. Continuation of Mr. Davy's paper. The author 

 analysed every product with great care, and investigated all the 

 new or peculiar appearances with unusual fidelity and minute- 

 ness, in order to discover accurate data for a correct rationale of 

 this new fulminating powder, which he considers as a triple salt, 

 composed of oxide of platinum and ammonia. It explodes gen- 

 tly at the temperature of 300 Fab. and violently at 400; whereas 

 the aurum fulminans explodes violently at temperatures be- 

 tween 120 and 300. From a great number of experiments 

 Mr. D. states that 100 grains of this fulminating platinum con- 

 sists of oxide of platinum 82".), of which 72 are metal and 10'5 

 oxvgen; of ammonia 9, and water 8"5 = 100. 



Feb. 20. The Astronomer Royal communicated some of his 

 Observations on the Parallax of the fixed Stars. Mr. Pond has 

 not yet completed the series of his observations; but from what he 

 has already observed he is inclined to dissent from Dr. Brinckley's 

 opinion, and to (juestion the existence of any parallax in certain 

 of the fixed sters, in consequence of finding the changes so very 

 small. 



KOYAL 



