226 THE ATOMIC WEIGHTS. 



4.27IO-1 „3sgg 37.507 



4.2752 J 37-545 



5.6860 1 ^^^^gg 37.460 



5.6901 > 37.487 



4.4117 11.8014 37-383 



4.9999 13.3965 37-322 



5.2409 14.0679 37.250 



Mean, 37.434, ± .0149 

 Pfeifer found, 37.485, ± .0198 



General mean, 37.452, Hr .0119 



If Ag =^ 108, Popper's figures give in mean Sb = 121.3. 



I am inclined to attach slight importance to these electrolytic data, 

 for the reasons that it would be ver}' difficult to ensure the aljsolute 

 purity and freedom from occlusions of the antimony as weighed, or to 

 guarantee that no secondary reactions had modified the ratios. 



The work done by Bongartz* in 1883 was quite diff"erent from any of 

 the determinations which had preceded it. Carefully purified 'antimony 

 was weighed as such, and then dissolved in a concentrated solution of 

 potassium sulphide. From this, after strong dilution, antimony trisul- 

 phide was thrown down by means of dilute sulj)huric acid. After 

 thorough washing, this sulphide was oxidized by hydrogen jieroxide, by 

 Classen's method, and the sulphur in it was weighed as barium sulphate. 

 The ratio measured, therefore, was 2Sb : 3BaS0^. and the data were as 

 follows. The BaSO^ equivalent to 100 parts of Sb is the ratio stated : 



0436 



We have now before us the following ratios, good and bad, from which 

 to calculate the atomic weight of antimony. The single results obtained 

 by Weber and by Unger, being unimportant, are not included : 



* Ber. Deutsch. Chem. Gesell., 16, 1942. 1883. 



