THE FINAL RESULTS. 87 



In comparing this result with that of Stas on argentic sulphate, it may 

 be noted that Stas found in silver sulphate 69.203 per cent of silver. Be- 

 cause Richards and Wells found in argentic chloride - 100 -- 75.2632 



132.867 



per cent, it is clear that our results indicate 0.91933 X 75.2632 -- 69.192 

 per cent of silver in silver sulphate, or 0.011 less than Stas's, one is forced 

 to the conclusion that Stas's argentic sulphate was not completely reduced 

 by hydrogen, and that his silver obtained in this way was no purer than 

 the silver used in his other work. The only test of complete reduction 

 used at the time was the solution of the residual metal in nitric acid ; but 

 this test could not reveal undecomposed sulphate and might not reveal 

 traces of sulphide. 



THE ATOMIC WEIGHT OF SULPHUR. 



The interpretation of the new results is very similar to that already dis- 

 cussed in the preceding paper on nitrogen and silver. In this case, as in 

 that, there are two uncertain ratios ; and one of these ratios, namely, that 

 of silver to oxygen, occurs in each. In the present case, the other uncer- 

 tain ratio is that of sulphur to oxygen, while in the former case the other 

 uncertain ratio was that of nitrogen to oxygen. 



In order to obtain a complete solution of the numerical relations in either 

 of these cases, it is therefore obviously necessary to obtain another series 

 of results, bringing in such a ratio as that of silver to sulphur, or oxygen 

 to sulphur, or chlorine to oxygen. Such an additional ratio is not known 

 at present with modern accuracy. Because of the fact that silver and 

 oxygen are concerned in each of the cases, a single new result, properly 

 chosen, will solve both problems at once ; but of course many new results 

 with different compounds, confirming one another, are greatly to be 

 desired. As has been said in the foregoing paper, some of these are 

 already in the process of determination at Harvard College, and it is 

 intended to pursue the matter further at the University of Berlin as well. 



For the present it is necessary to state the interpretation of the results 

 in a conditional manner, assuming various possible ratios between oxygen 

 and silver, and stating the corresponding values for sulphur. In the fu- 

 ture, when the assumed relationship is replaced by knowledge of the facts, 

 intelligent choice can be made between the alternatives. 



If oxygen is taken as 16.000, the following table gives the atomic 

 weights of sulphur corresponding to the several atomic weights of silver. 



Atomic Weight of Sulphur. 



If Ag = 107.930 and 01 = 35.473, 5 = 32.113 

 If Ag = 107.890 and Cl = 35.460, 3 = 32.078 

 If Ag= 107.880 and Cl = 35.457, 5 = 32.069 



