214 On some Combinations of Platina. 



and the effect to be connected with the production of sul- 

 phuric acid. I was surprised to find that it exhibited the 

 properties of oxygen. I cannot account for this phaeno- 

 menon ; it can scarcely be owing to the absorption of 

 common air, the volume of gas being about eight times 

 greater than that of the hydrosulphuret. When small 

 lumps of it are introduced into nitric acid, a slight detonat- 

 ing noise is produced, and the substance instantly falls to 

 pieces. These effects are connected with the decomposition 

 of the nitric acid and the formation of sulphuric acid, and 

 are much increased, wilh the rapid disengageinent of nitrous 

 gaSj on the application of a gentle heat. When a little of 

 the hydrosulphuret is put into concentrated sulphuric acid, 

 gas is disengaged from it : on heating it, a hissing noise is 

 produced, and gas copiously evolved ; but it seems to be 

 quite insoluble in this acid. Muriatic, phosphoric, and 

 acetic acids occasion a disengagement of gas from the hy- 

 drosulphuret ; but the action of these acids on it is very 

 limited, and attended by no other effect worthy of notice. I 

 have not examined the gas evolved bv the agency of these 

 acids on the hydrosulphuret. The quantities on which I have 

 operated have been too small for this purpose. When it is in- 

 troduced into a strong solution of pure potash or ammonia, 

 a hissing noise is produced; but there is apparently no fur- 

 ther effect. When it is exposed to the atmosphere, it absorbs 

 oxygen, and sulphuric acid is formed. Five grains of it ex- 

 posed in small lumps for four days gained more than -j^ths 

 of a grain in weight, and this increase was in a gradually di- 

 minishing ratio, in proportion to the time. It then furnished, 

 by its decomposition in close vessels, sulphureous acid gas, 

 water, and sulphuret of platina. When the hydrosulphuret 

 is heated in nitrous gas, it becomes an ignited mass ; when 

 oxygen cas and moisture are present, a white crystallized 

 substance appears to be formed, which furnishes nitrous 

 gas and sulphuric acid by the agency of water. I have not 

 minutely examined these results. Nitrous acid vapour 

 acts spontaneously od the hydrosulphuret, occasions a hiss- 

 ing noise, and the formation of sulphuric acid. When 

 the hydrosulphuret is heated to redness in close vessels 

 over mercury, the products are sulphuretted hydrogen gas, 

 with a little sulphureous acid gas, water, sulphur, and sul- 

 phuret of platina. When it is introduced into chlorine gas, 

 an immediate action is produced, and copious white fumes 

 are evolved ; these effects are much increased by the agency 

 of heat, and a substance of a brown and blackish colour is 

 obtained which gives off gas, and is for the most part solu- 

 ble 



