160 THE ATOMIC WEIGHTS. 



synthesis. Weighed quantities of oxide were dissolved in potassium 



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



trolytically. The weights are reduced to vacuum standards. 



CdO Taken. Cd Found. Per cent. Cd. 



.34767 .30418 87.491 



.41538 .36352 87.515 



1.04698 .91618 87.507 



1.04066 .91500 87.493 



1.26447 1.10649 87.506 



.78493 .68675 87.492 



.86707 .75884 87.518 



.67175 .58785 87.510 



1.44362 1.26329 87.508 



Mean, 87.5044, ± .0023 



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

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

 ous methods by which that constant has been determined. Neverthe- 

 less, it gives many data which seem to have positive value, and which 

 are certainly fit for discussion along with those which have preceded 

 this paragraph. Bucher begins 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 reduc- 

 tion was effected by heating in jaclceted porcelain crucibles, with various 

 precautions, and the results obtained, reduced to vacuum standards, are 



as follows : 



Oxalate. Oxide. Per cent. Oxide. 



1.97674 I. 26414 63.951 



1.94912 1.24682 63.968 



1.96786 1.25886 63.971 



1.87099 I. 19675 63.958 



1.37550 .87994 63.972 



1. 33313 -85308 63.991 



I 94450 1.24452 64.002 



2.01846 I. 29210 64.014 



Mean, 63.978, dr .0052 



Combining this with the means found by previous experimenters, we 

 have for the percentage of oxide in oxalate — 



Lenssen 64.010, zb .0140 



Partridge 63.962, zh .0010 



Morse and Jones 64.003, i .0042 



Bucher 63.978, zfc .0052 



General mean 63.966, ± .0010 



* "An examination of some methods employed iu determining the atomic weight of cadmium." 

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



