OF ARTS AND SCIENCES. 21 



This is the ratio of the atomic weight of silver to that of bromine, 

 and corresponds to the second decimal place with the determinations 

 of Stas as well as with those of Dumas. 



"We have now furnished as evidence of the atomic weight of anti- 

 mony, — 



1. The mean of fifteen analyses of bromide of antimony purified by 

 crystallization from sulphide of carbon, with an extreme variation be- 

 tween 119.4 and 120.4 for all the fifteen analyses. 



2. The mean of five analyses of bromide of antimony purified by 

 distillation and sublimation, with an extreme variation between 119.90 

 and 120.08. 



3. The mean of five volumetric analyses of bromide of antimony, 

 also purified by distillation and sublimation, with an extreme variation 

 between 119.98 and 120.02. 



4. Two gravimetric determinations of the bromine in two of the 

 portions of bromide of antimony used in the volumetric analyses, but 

 still essentially distinct determinations, which gave almost identical 

 results. 



Bringing these several means together as of equal value, we have : — 



Furthermore, we have shown by the last two determinations, that 

 the ratio of the atomic weight of the silver to that of the bromine, 

 used in our experiments, was 108.00 to 80.00, and hence that the 

 »"atio of the atomic weights of bromine silver and antimony must be 



Ag : Br : Sb = 108.00 : 80.00 : 120.00, 



with a probable error not exceeding 0.01 in any case. Of course our 

 experiments only serve to fix the ratio between these three quantities, 

 and any considerations which may lead chemists to change the value 

 of one of the quantities must affect the other two in the same propor- 

 tion. If with Stas we take Ag = 107.66, then Br r= 79.75, and Sb=: 

 119.63; and in this connection the fact should be recalled that the 

 ratio of Ag to Br, according to Stas, is essentially identical with that 

 given above, and the same as that found both by Dumas and by Ma- 



