16 PROCEEDINGS OF THE AMERICAN ACADEMY 



during this process. That at this point the charring is perfect, and 

 that after the conversion no tartaric acid is left undecomposed, we have 

 proved by several times heating the resulting gray sulphide to 300", 

 and ascertaining that it underwent no additional loss of weight. As 

 is well known, small quantities of tartaric acid are completely decom- 

 posed at this last temperature.* In the two determinations we are 

 discussing, the carbonaceous residue was collected on a weighed filter, 

 and its weight subtracted from the total weight of the dried precipitate. 

 All the remainder was pure Sb._,Sg ; and, from its weight and that of 

 the antimony used, the ratio between the atomic weight of sulphur and 

 that of antimony was very easily calculated. The results were as 

 follows : — 



First Determination. 



Weight of antimony taken 2.0554 grammes. 



Weight of precipitate dried at 240'^ . . 2.8878 ,, 

 „ carbonaceous residue 0147 „ 



Sb^Sg 2.8731 



antimony as above .... 2.0554 



Corresponding weight of sulphur . . . 0.8177 



Hence when S = 32, then Sb = . . 120.6 „ 



Second Determination. 

 Weight of antimony taken 2.0346 grammes. 



Weight of precipitate dried at 240° . . 2.8513 „ 

 „ carbonaceous residue . . . 0.0073 „ 



Sb^Sj 2.8440 



antimony as above .... 2.0346 



Corresponding weight of sulphur . . . 0.8094 „ 



Hence when S = 32, then Sb = . . 120.6 „ 



It is evident that these results, so far as they go, very greatly tend 

 to confirm the value Sb= 120.3 obtained by Schneider; and, in the 

 light of the knowledge we have since obtained, the reason that our first 



* Gmelin's Handbook of Chemistry, Cavendish Edition, v^l. x. p. 209. 



