816 SIE B. C. BEODIE ON TlIE CALCULUS OF CHEMICAL 0PEEATI0N8. 



(3) Symbol of Sulphur. — It has been shown by the recent experiments of Deville and 

 Troost that the density of the vapour of sulphur above a temperature of 860° C. becomes 

 constant, and approximates to 32, the density of hydrogen being 1. This being the case, 

 the ponderable matter of 2 units of sulphide of hydrogen is identical with the ponderable 

 matter of 2 units of hydrogen and 1 unit of sulphur. Hence, putting a""^' as the symbol 

 of sulphide of hydrogen, and a"^' as the symbol of sulphur, 



2a'"r'=2a+a"^', 

 and 



and 



2m=2+%, 2mi=»i, ': 



whence 



n =0, m=l, 



«i=2, mi=l, 

 a minimum. 



And putting the density of sulphide of hydrogen as 17, 



m-'tmyW{6)z=Vl , 

 and 



Hence we have, as satisfying the conditions afforded by the above equation, 



Symbol of sulphur fi. 



Symbol of siilphide of hydrogen ot,6. 



If we assume the density of sulphur to be correct as determined before the recent 

 experiments referred to, the simplest statement which can be made as to the decompo- 

 sition of sulphide of hydrogen is, that 6 volumes of sulphide of hydrogen are decomposed 

 into 6 volumes of hydrogen and 1 volume of sulphur-vapour ; in which case 



and 



6m=6-|-», 6mi=Wi, 



which gives as the minimum solution 



n =0, m =1, 



71^ = 6, 7^1=1, 



and 



w(^i)=16. 

 Hence 



6^=6. 



The symbols, therefore, may be in either case expressed by the same prime factors. 

 In the latter case, we have 



Symbol of sulphur ^, 



Symbol of sulphide of hydrogen as before u6. 

 By similar reasoning to that employed in the determination of the symbol of the 

 peroxide of hydrogen, we arrive at the following symbols. 



