344 



CARNEGIE INSTITUTION OF WASHINGTON. 



which would lower it. As soon as these impurities can be quantita- 

 tively estimated, the research will be completed. As it is, the results 

 certainly support the final corrected value obtained by Baxter and 



Chapin, 144.275. 



The Atomic Weight of Cadmium. 



In several recent investigations Hulett and his collaborators have 

 obtained values for the atomic weight of cadmium agreeing fairly 

 closely at 112.3, by depositing electrolytically, in a mercury cathode, 

 the metal in hydrated and anhydrous cadmium sulphate and anhydrous 

 cadmium chloride and bromide, and by comparison of cadmium de- 

 posited in mercury with an electrolytic silver deposit obtained simul- 

 taneously. The above value is more than 0.1 unit lower than the one 

 obtained by Baxter, Hines, and Frevert by the determination of the 



halogen in the fused chloride and bromide. So large a discrepancy 

 was disturbing, and therefore Mr. M. L. Hartmann undertook the elec- 

 trolytic determination of cadmium in anhydrous cadmium chloride. 



In the first place, a special electrolytic cell was devised, constructed of 

 glass, with platinum cathode and anode permanently fused into the 

 walls. The cell was first weighed with a charge of mercury; then a 

 quartz boat, in which a weighed amount of cadmium chloride had been 

 fused, was introduced and covered with water. After a current of 

 electricity had been passed thi-ough the solution until practically all the 

 cadmium was deposited in the mercury, the amalgam was washed with 

 water and alcohol, dried in a vacuum, and reweighed. The washings 



