Sulphur and Phosphorus with Platina. 33 



heated to a dull red for a few minutes to expel every thing 

 volatile. A quantity of muriatic acid gas having the odour 

 of phosphorus and some nitrogene gas came over, a little 

 muriate of ammonia with the excess of phosphorus sub- 

 limedj and super-phosphurel of platina was formed. 



Physical mid Chemical Properties. 



The physical and chemical properties of super-phosphuret 

 of platina resemble those of the super-sulphuret. Its co- 

 lour is iron black, or very dark gray. It is in fine powder, 

 or in small pieces in a loose state of aggregation. When 

 in this last state it exhibits a dull metallic lustre. It marks 

 the fingers or paper, but the lustre it gives is much inferior 

 to that of the super-sulphuret. Its specific gravity is about 

 5*28, that of distilled water being 1. It has no taste or 

 smell. It did not appear to be affected by being exposed 

 to the atmosphere or water for some days. It is a non- 

 conductor of electricity. When it is heated on a thin slip 

 of platina below redness, it becomes an ignited mass and 

 diminishes in bulk, but its colour scarcely varies. On 

 raising the heat to whiteness by means of a blow-pipe, it 

 fuses, and perforates the platina with holes. It is but little 

 affected by the mineral acids at any temperatures. When 

 it is heated with fine zinc or iron filings, it undergoes little 

 change. It is partially decomposed with vivid ignition 

 when healeil with oxymuriate of potash, and oxygene gas 

 and chlorine gas are evolved. When mixed with the same 

 salt, and struck smartly with a hammer, it detonates with a 

 loud report. It is decomposed when heated in chlorine 

 gas, phosphoranc is formed, and a combination of chlorine 

 and platina remains ; but I have not yet examined these 

 results with precision. 



Composition. 



It was not easy to find unexceptionable methods of ana- 

 lysing the super-phosphuret of platina. The mineral acids 

 had no apparent action on it. Though oxymuriate of pot- 

 ash decomposed it, the process was tedious, and the results 

 by no means satisfactory. At a high temperature long 

 continued, it was decompounded ; but little dependence 

 could be put in this mode of operating, as in cases when 

 Hessian crucibles were used there was ahnost always a 

 considerable loss, and platina ones could not be employed 

 without insuring their destruction. 



The only method which seemed to offer satisfactory re- 

 Vol. 40. No. 171. Jw/y 1812. C suits. 



