360 On some Combinations ofPlatina, 



grains, 



Oxygene gas 3*75 cub. inches = l*27 



Metallic platina iriO 



Sulphate of soda 1 '30 



Water 1-33 



15-00 

 Hence, this experiment indicates the component parts of 

 soda sulphate of platina — 



Oxide of platina . . . 82-46 

 Sulphate of soda.. 8-66 

 Water 8-88 



100-00 



The difference in these experiments appears to be owing 

 to the circumstance, that a little of the salt was carried into 

 the neck of the retorts during the expulsion of the water, 

 which was not noticed in the preceding experiments. 



In the potash sulphate of platina, and soda sulphate of 

 platina, as in the sulphate of platina, the metal, it is pre- 

 sumed, must be at its minimum of oxidation, in the state 

 of black oxide; and there is a very near coincidence as to the 

 composition of this oxide, furnished by the decomposition 

 of all these substances. 



10. Of Aynmonla Sxdphate of Platina. 

 This compound, like the preceding, is made by neutra- 

 lizing an aqueous solution of sulphate of platina by pure 

 ammonia, and boiling the fluid for a few minutes. After 

 being washed with distilled water, and dried for some hours 

 at a temperature not exceeding 212° Fahrenheit, it exhibits 

 the following properties. 



Physical and Chemical Properties. 

 It is of a lightish brown colour. It is in fine powder ar 

 small loosely aggregated lumps. It is tasteless, and insolu- 

 ble in water. It undergoes no apparent change by exposure 

 to the atmosphfre. It dissolves slowly in cold muriatic 

 acid, and readily at a gentle heat, ft is soluble in su'phu- 

 ric acid at a moderate heat. It is insoluble in nitric acid 

 at a boiling heat. When strong nitric acid is boiled to 

 dryness on it^ it is decompouncied, and a black substance re- 

 mains, which I auj inclined to think is composed of black 

 oxideof platinawiih nitrate and sulphateof ammonia. When 

 it is boiled in conceriirated phosphoric acid, a small quantity 

 of it is dissolved. It is insoluble in acetic acid. It is decom- 

 pounded when boiled with a strong solution of pure potash 



or 



