202 THE ATOMIC WEIGHTS. 



Ammonium Stannichloride. 



Mean, 32.369, ± .0088 



One other method of determination for the atomic weight of tin was 

 employed by Bongartz and Classen. Electrolytic tin was converted into 

 sulphide, and the sulphur so taken up was oxidized by means of hydrogen 

 peroxide, by Classen's method, and weighed as barium sulphate. The 

 results, as given by the authors, are subjoined : 



Sn Taken. Per cent, of S Gained. 



2.6285 • 53.91 



.7495 53.87 



1.4785 53.94 



2.5690 53.94 



2.1765 53.85 



1.3245 53-88 



.9897 53.83 



2.7160 53.86 



Mean, 53.885, ± .0098 



This percentage of sulphur, however, was computed from weighings 

 of barium sulphate. What values were assigned to the atomic weights 

 of barium and sulphur is not stated, but as Meyer and Seubert's figures 

 are used for other elements throughout this paper, we may assume that 

 they apply here also. Putting = 15.96, S = 31.98, and Ba = 136.86, 

 the 53.885 per cent, of sulphur becomes 392.056, ± .0713 of BaSO« the 

 compound actually weighed. This gives us the ratio — 



Sn : 2BaSO^ : : lOO : 392.056, zfc .0713 



as the real result of the experiments, from which, with the later values 

 for Ba, S, and 0, the atomic weight of tin may be calculated. 



