38 Combinations of Sulphur and Phosphorus with Platina. 



stinct manner. They are derived from the foregoing ex- 

 periments, 



Grs. of Platina. Sulphur. Phospliorus. 



r 19-04 sub sulphuret fsi-Ol sub-phosphuret. 

 \38-8 suj)er-sulphuret \42'85 supcr-phosphur. 



Platina has a very strong affinity for phosphorus. This is 

 exhibited in a remarkable manner in the energy with uhich 

 they combine. I am acquainted with no simple or accurate 

 method of analysing combinations of the metals with phos- 

 phorus. As chlorine decomposes the phosphurets of pla- 

 tina with facility, it seems to offer a simple mode of exa- 

 mining refractory compounds of this kind. 



Zinc has been supposed to have but little affinity for 

 sulphur, because chemists have not been able to combine 

 these substances directly. In the preceding p.qges it is 

 stated, that zinc filings decompose the super-sulphuret of 

 platina with ignition. The experiments I made in the 

 autumn of last year, lead me to conclude that the affinity 

 of zinc for sulphur is at least equal to that of iron. The 

 intensity of their mutual attraction is evident from the 

 circumstance, that zinc filings and sulphur when exposed 

 to an elevated temperature in exhausted tubes combine 

 with vivid ignition and flame. I also found that zinc 

 filings by the agency of heat decompose the sulphurets of 

 lead, molybdena, copper and nickel, and sulphuret of zinc 

 is formed. 



The combinations of platina with sulphur and phosphorus 

 will probably admit of some useful and (Economical appli- 

 cations. The sulphurets of platina are insoluble in all the 

 mineral acids, and this property seems to afford an easy 

 method of obtaining pure platina from the crude ore. For 

 this purpose the nitro-muriatic solution should be neutra- 

 lized by aminonia, the precipitate washed, dried, and heated 

 with an excess of sulphur; sulphurets of the different me- 

 tals in the crude ore would thus be obtained, and they may 

 be all separated from the sulphuret of platina by the agency 

 of the mineral acids. As the super-sulphuret has the pro- 

 perty of giving to paper, 3cc. a considerable degree of lustre, 

 it may perhaps be used as a pigment, in cases where per- 

 manency and lustre are required. 



Platina is well known to be admirably adapted for vessels 

 and instruments employed in oeconomical or experimental 

 processes ; i)ut its application is very limited in conse- 

 quence of its high commercial value. It vi'ould be a very 

 desirable and important object to be able to give a perma- 

 nent coating of platina to kitchen utensils, steel in.nru- 



ments. 



