S62 0?i some Comllnations of Platina. 



.in a similar manner, several comparatively feeble explosion* 

 occurred. In these instances, as also when it was exploded 

 on glass, the materials wtre all dissipated, there was not 

 the slightest trace of the platnia, which in all probability 

 must be reduced in the process. It does not explode by 

 percussion or friction, nor could I fire it by flint and steel. 

 The detonating properties of this compound are far inferior, 

 and ditler materially from those belonging to fulminating 

 silver, gold, and mercury; vet they seem sufficiently distinct 

 to entitle it to a place in this class of bodies, and serve to 

 complete the analogy existing between the noble metals. 



Fulminating platina is soluble in sulphuric acid at a 

 moderate heat. It dissolves but slowly in boiling muriatic 

 flcid. It is slightly soluble in concentrated phosphoric acid, 

 and the solution is of a very deep colour like the sulphate : 

 on the addition of water, a brown precipitate takes place, 

 and the fluid remains turbid and slightly coloured ; but 

 aher a short time, all the platina is precipitated, and the fluid 

 remains colourless. — 1 have not examined this substance, 

 but am inclined to think it is a phosphate of platina. 



Fulminating platina is slightly soluble in boiling pure 

 nitric acid : the solution affords a precipitate with muriate 

 of barytes ; and with all the alkalies, a yellow precipitate. 

 Whether this yellow sulistance be an oxide or a triple com- 

 pound of the alkalies oxide and acid, I have not ascertained. 

 When it is boiled to dryness with nitric acid, a black sub- 

 statice remains, which is probably a triple compound. It is 

 insoluble in acetic acid, and when boiled to dryness with 

 this acid it still retains its detonating properties. 



I cannot speak with certainty as to the constitution of 

 this compound ; but from the foregoing statements I am 

 disposed to believe, it is analogous to the ammonia sulphate 

 of platina, and only differs from this substance, in the 

 proportions of its constituent parts. 



12. Of Alumine Sulphate of Platina. 

 This compound is procured, by treating an aqueous solu- 

 lion of sulphate of platina with muriate of alumine, a 

 tOj)ious gelatinous precipitate of a brown colour occurs : 

 after being well washed with pure water, and dried for a 

 considerable time at a temperature not exceeding 212° 

 Fahrenheit, it exhibits the following properties. 



Physical avd Chemical Properties. 



Its colour is black, or extremely dark brown. It is in small 



lumps. It has a shining resinous lustre, resembling that of 



potash sulphate of platina. It is tasteless, insoluble in water, 



and unaflected by the atmosphere. When it is heated on 



a thiu. 



