«8 On the Combinations of 



were founded on the an ilogy, that most of the metallic 

 sulphurets co';Id be formed by the direct union of their 

 elements. Sulphur and platina were mixed and '.eated to- 

 gether in the atmosphere, or sulphur was projected on the 

 metal previously heated to redness ; but by these methods 

 no chemical union of the substances took place. 



On resuming the subject, there appeared to me to be 

 two modes which had not hitherto been tried; namely, 

 that of heating the ammonia-muriate of plalina in contact 

 with sulphur; and that of exposing the metal and sulphur 

 to an elevated teniperature in an exhausted tube. Both 

 these methods seemed favourable to combination. In one 

 case, the metal was in a very minute state of division, and 

 its neutro-saline ingredient volatile at a moderate heat ; in 

 the other, the volatility of the sulphur would be counter- 

 acted, and the niaterials exposed to a degree of heat which 

 was impracticable in the atmosphere. On making these 

 experiments, I had the satisfaction to find that, in both in- 

 stances, sulphurets of platina were formed. 



As these compounds contain different proportions of 

 sulphur, and possess characteristic properties which will be 

 enumerated in the sequel, they will be distinguished by the 

 addition of the words super and sub to their common 

 names ; the former indicating the greater, the latter, the 

 lesser proportion of the inflammable principle : these di- 

 stinctions have been already adopted by chemists. 



To avoid unnecessary details, it may be proper in this 

 place to state, that the platina employed in all mv experi- 

 ments was procured by decomposing the ammonia-muriate 

 of this metal at a red heat in a platina crucible. The am- 

 monia-muriate of platina used, was obtained by ireating a 

 strong acid solution of purified platina with muriate ot am- 

 monia ; the yellow precipitate, after being washed with 

 distilled water, was dried for some days on a sand-bath at 

 a temperature varying from 200' to about 340^ Fahrenheit, 

 and coniained 44*5 grains of platina per cent. 



3. Of Super- Sulphur et of Platina^ 



This compound was obtained by heating in a glass retort 

 over mercury, a mixture of the ammonia- muriate of pla- 

 tina with about two-thirds of its weight of flowers of 

 sulphur. The retort was gradually heated to a dull red by 

 means of a spirit-lamp, and the process was continued for 

 a short time after the gas ceased to be produced : a quan- 

 tity of muriatic acid gas with some nitrogene came over, a 

 little muriate of ammonia, with the excess of sulphur sub- 

 limed. 



