1815,] in the Physical Sciences. 19 



lations of Berzelius from approaching to accuracy ; though it were 

 to be wished that experiments on the oxides were made in a less 

 exceptionable manner than by combining them with muriatic acid. 



2. Oxides of Platinum. — To determine the composition of 

 protoxide of platinum, Berzelius proceeded in the following 

 manner. He dissolved a quantity of pure platinum powder in 

 nitro-muriatic acid, evaporated the solution to dryness, to get rid 

 of the excess of acid, and then exposed the salt upon a sand-bath 

 till all evolution of chlorine was at an end. The salt thus treated 

 had an olive-green colour, and was promuriate of platinum. To 

 ascertain its composition, he decomposed it by a red heat. Ten 

 parts of it thus treated left 7'33 of metallic platinum, while 2-67 

 parts of chlorine gas made their escape. Now he assumed that the 

 chlorine gas is a compound of muriatic acid and oxygen, and that 

 the 2-67 of it contain just the quantity of oxygen necessary to 

 convert 7-33 parts of platinum into protoxide; but 100 parts of 

 chlorine gas, according to Berzelius, are composed of 100 muriatic 

 acid and 29-454 oxygen ; therefore 2-67 contain 0-60753 and prot- 

 oxide of platinum is composed of 



Platinum 92-35 100 



Oxygen 7-65 8-287 



Berzelius determined the oxygen in the peroxide of platinum in 

 the same way as he did that in the peroxide of gold. He ascer- 

 tained how much mercury was necessary to precipitate a given 

 quantity of platinum in the metallic state. The result was, that 

 100 mercury precipitate 48-23 of platinum. He therefore con- 

 siders the peroxide of platinum as composed of 



Platinum 85-93 100 



Oxygen 14-07 1638 



100-00 



But if we reckon the peroxide of mercury to contain 100 metal 

 + 8 oxygen, which I believe to be very near the truth, then per- 

 oxide of platinum is composed as follows : — 



Platinum 85-773 100 



Oxygen 14-227 ^^'^^7 



100-000 



Now this gives the quantity of oxygen very nearly double that 

 which was found in the protoxide. 



3. Oxide of Palladium.— Bcr/xVms could only find one oxide of 

 palladium. He employed the same method to analyse it that suc- 

 ceeded with him in tlie analyses of the peroxides of gold and pla- 

 tinum. He ascertained how much mercury is necessary to decom- 

 pose a given quantity of muriate of palladium, and reduce that 



