PLATINUM. 457 



lent to an atom of sulphuric acid, it follows that 



12 must denote an atom of platinum : 2 being A 1 to . m of 



* f platinum. 



equivalent to 2 atoms of oxygen, it is obvious 

 that the oxide of platinum in the sulphate, which 

 is the peroxide, is a compound of 1 atom plati- 

 num and C 2 atoms oxygen. Consequently, its Atom . of 

 atomic weight is 14. 



The knowledge of the atomic weight of pla- 

 tinum deduced from this salt, enables us to de- 

 cide, that the triple chlorides of platinum and 

 potash, and platinum and soda, contain 1 atom 

 of platinum united to 2 atoms of chlorine. 



Mr. Edmund Davy made an analysis of the 

 sulphate of platinum, a good many years ago, 

 and his results, though not quite accurate, con- 

 stitute near approximations to the truth. It was 

 his analysis that pointed out to me the mode 

 which I had to follow. My method being nearly 

 the same with his, I considered it unnecessary 

 to describe it minutely. Mr. E. Davy's results 

 are as follows :* 



Platinum 12-4697 



Oxygen 1-5352 



Sulphuric acid 4-9951 



19-0000 



The weight of an integrant particle of the salt 

 deduced from this analysis is the same as from my 

 own, namely 19. The proportion of sulphuric 



* Phil Mag. XL. 354. 



