ATOMIC WEIGHTS 



239 



The second method employed by Morse and Jones was that of Lenssen 

 with cadmium oxalate. This salt they found to be somewhat hygroscopic, 

 a property against which the operator miist be on his guard. The data 

 found are as follows : 



Mean, 64.003, ± .0042 



Hence Cd = 112.03. 



Lorimer and Smith/ like Morse and Jones, determined the atomic 

 weight of cadmium by means of the oxide, but by analysis instead of 

 S3mthesis. Weighed quantities of oxide were dissolved in potassium 

 cyanide solution, from which metallic cadmium was thrown down elec- 

 trolytically. The weio-lits are reduced to a vacuum standard : 



Mean, 87.5044, ± .0023 



Hence Cd = 112.042. 



Mr. Bucher's dissertation " upon the atomic weight of cadmium does 

 not claim to give any final measurements, but rather to discuss the various 

 methods by which that constant has been determined. jSTevertheless, it 

 gives many data Avhich seem to have positive value, and which are cer- 

 tainly fit for discussion along with those which have preceded this 

 paragraph. Bucher began with cadmium purified by distillation nine 

 times in vacuo, and from this his various compounds were prepared. His 

 first series of determinations was made by reducing cadmium oxalate to 

 oxide, the oxalate having been dried fifty hours at 150°. The reduction 

 was effected by heating in jacketed porcelain crucibles, with various pre- 

 cautions, and the results obtained, reduced to a vacuum standard, are as 

 follows : 



1 Zeitsch. anorg. Chem., 1, 364. 1S92. 



- " An examination of some methods employed in determining the atomic weight of cadmium." 

 Johns Hopkins University doctoral dissertation. By John E. Bucher. Baltimore, 1895. 



