456 GOLD, PLATINUM, PALLADIUM, &c. 



ing to enable us to decide which of these two 

 suppositions is the true. After some unsuccess- 

 ful attempts, I at last found that the sulphate of 

 platinum put it in my power to solve the problem. 

 4. I formed a quantity of sulphate of platinum 

 by the process pointed out by Mr. Edmund Davy. 

 f f 19 grains of this dry sulphate were put into a 

 platinum, small green glass retort, and exposed to a red 

 heat till the platinum was reduced to the metal- 

 lic state; it weighed exactly 12 grains. This 

 experiment was repeated several times, in order 

 to collect the oxygen gas evolved by the reduc- 

 tion of the platinum, and to determine the 

 quantity of sulphuric acid separated; for both 

 these products could not be conveniently collect- 

 ed at the same time. The oxygen gas evolved 

 was rather less than three cubic inches, and 

 amounted, therefore, very nearly to 2 grains. The 

 sulphuric acid was a very little less than 5 grains ; 

 the reason was, that a little sulphurous acid was 

 disengaged, which I found it difficult to obtain 

 without some loss. From these experiments it 

 is obvious enough, that the constituents of sul- 

 phate of platinum are 



Platinum 12 



Oxygen 2 



Sulphuric acid 5 



19 



Now the salt was neutral, and 5 being equiva- 



