114 THE ATOMIC WEIGHTS. 



From the first series CdBrj = 271.498, zh .032 



From the second series__ " = 271.505, ± .027 



General mean " = 271.502, ± .0215 



Hence Cd = 111.966, ± .043. 



According to Huntington's own calculations these experi- 

 ments fix the ratio between silver, bromine, and cadmium 

 as Ag : Br : Cd : : 108 : 80 : 112.31. This result militates 

 strongly against Prout's hypothesis. 



Upon combining all the determinations we get the follow- 

 ing result : 



V. Hauer Cd := 111.684, ± •'^40 



Lenssen " = 11 1.803, ± -^^^ 



Dumas " -^^ 11 1.969, ±: .065 



Huntington " = 1 11.966, zb .040 



General mean " = 111.835, 4= .024 



Or, if = 16, then Cd = 112.092. 



It will be seen that Dumas and Huntington's determina- 

 tions, both made with haloid salts of cadmium, agree with 

 wonderful closeness, and so confirm each other. On the 

 other hand, v. Hauer's data give a value for the atomic 

 weight of cadmium which is much lower. Apparently, v. 

 Hauer's method was good, and the reason for the discrep- 

 ancy remains to be discovered. Until it is ascertained I 

 prefer to use the above mean value for Cd, rather than to 

 adopt one investigation and rtyect the others. 



MERCURY. 



In dealing with the atomic weight of mercury we may 

 reject the early determinations by Sefstrom* and a large 

 part of the work done by Turner.t The latter chemist, in 

 addition to the data which will be cited below, gives figures 



* Sefstrom. Berz. Lehrb., 5th Ed., 3, 1215. Work done in 1812. 

 fPhil. Trans., 1833, 531-535- 



