Sulphur and Phosphorus ivilh Platina. 35 



of platina, the odour of phosphorus is exhaled, and its sur- 

 face assumes a darker tint. When the heat is urged to 

 whiteness it combines with the platina, which it per- 

 forates with holes. It is partially decomposed with igni- 

 tion when heated with oxymiiriate of potash. When it is 

 healed in chlorine gas, the results are similar to those ob- 

 tained in the case of the super-phosphuret. 



Composition. 



The difficulties which were opposed to the direct analysis 

 of the super-phosphuret, equally apply to the sub-phos- 

 phuret. Its composition was ascertained by the direct 

 union of its elements; and though only comparatively small 

 quantities of the materials could be emploved with safety, 

 yet from the manner of operating, it would seem that the 

 results are susceptible of considerable accuracy. 



From several experiments I. have selected two of the 

 most accurate, from which its composition is determined. 



First Experiment. 10 grains of platina heated with phos- 

 phorus in an exhausted tube for about seven minutes 

 furnished 12-1 grains of sub-phosphuret. 



From this experiment 100 grains contain 



Platina 82-64: 



Phosphorus I/'SS 



lOOOO 



Second Experiment. 20 grains of platina heated with phos- 

 phorus in an exhausted tube, precisely as in the other ex- 

 periment, aflorded 24-3 grains of sub-phosphuret. This 

 experiment, which I regard as the more accurate of the two, 

 gives the component parts of sub-phosphuret of platina as 



Platina 82-3 



' Phosphorus 17" 7 



100 

 The difference between these experiments is not consi- 

 derable. From a comparison of them with others, I shall 

 venture to consider the mean as the nearest approximation. 

 Hence 100 parts will be composed of 



Platina .... 82-3 

 Phosphorus 17'5 



1000 



General Observations, i^c. 



On the received opinions concerning the composition of 

 C 2 the 



