32. On the Comlinatlons of 



high temperatures in exhausted tubes; and from its being 

 in"a constant state of motion, particles of the sub sulphuret 

 formed, were occasionally deposited on the sides of the 

 tube with a little sulphur, and they could not easily be col- 

 lected. 



In two different experiments carefully made, 5 grains of 

 snb-sulphuret decomposed at a low red heat, in a platina 

 crucible, aflorded 4*2 grains of platina, and 5 : 4-2 : : 

 100 : 84. 

 Hence 100 parts of sub-sulphuret of platina contain 



Platina 84 



Sulphur... l6 

 100 



The sub-sulphuret of platina, whilst it possesses some 

 properties analogous to those of the super-sulphuret, differs 

 from it in colour, lustre, specific gravity, and proportion of 

 sulphur; properties sufficient to establish its existence as a 

 distinct combination. 



5. Of the Coinltnatioiis of Platina with Phosphorus. 



Chemists have hitherto paid but little attention to the 

 combinations of metals with phosphorus. The papers of 

 M. Pelletier appear to contain most of what is known 

 concerning these compounds. He first combined phos- 

 phorus with platina* by exposing the metal, phos- 

 phoric glass, and charcoal powder to a strong heat ; and 

 by projecting bits of phosphorus on platina heated to red- 

 ness. From the experiments f have made, 1 cannot but 

 regard the methods of M. Pelletier as very imperfect. 

 Platina and phosphorus combine with great facility, at a 

 heat considerably below redness ; at a red heat, a portion 

 of the phosphorus is expelled, and at still more elevated 

 temperatures the combination is nearly destroyed. 



Phosphorus, like sulphur, appears to combine in two 

 different proportions with platina. The same methods 

 employed in forming the sulphurets were successfully 

 adopted in making the phosphurets of platina, and they 

 will be marked by the same distinctions. 



6. Of Super-Phosplmret of Platina. 

 This compound was procured by heating together the 

 ammonia-muriate of platina with about two-thirds of its 

 weight of phosphorus in small bits, in a retort over mer- 

 cury. Towards the end of the experiment, the retort was 



* AnnaUide Chimit, tome i. p. 100, and tome xiii. p. 105. 



heated 



