236 



SMITIISONIAX MISCELLANEOUS COLLECTIOXS 



VOL. 54 



„ .0052 

 Hence Cd = 112.14. 



Next in order comes Huntington's ^ work, carried out in the laboratory 

 of J. P. Cooke. Bromide of cadmium was prepared by dissolving the 

 carbonate in hydrobromic acid, and the product, dried at 200°, was puri- 

 fied by sublimation in a porcelain tube. Upon the compound thus ob- 

 tained two series of experiments were made. 



In one series the bromide was dissolved in water, and a quantity of 

 silver not quite suflicient for complete precipitation of the bromine was 

 then added in nitric acid solution. After the precipitate had settled, 

 the supernatant liquid was titrated with a standard solution of silver 

 containing one gramme to the litre. The precipitate was washed by de- 

 cantation, collected by reverse filtration and weighed. To the weighings 

 I append the ratio between CdBr^ and 100 parts of silver bromide : 



Ratio, 72.423 

 72.415 

 72.415 

 72.435 

 72.437 

 72.410 

 72.405 



3.4773 



4.7593 



72.433 



Mean, 72.4216, ± .0028 

 Hence Cd = 112.18. 



The second series was like the first, except that the weight of silver 



needed to eft'ect precipitation was noted, instead of the weight of silver 



bromide formed. In the experiments marked with an asterisk, both the 



amount of silver required and the amount of silver bromide thrown down 



were determined in one set of weighings. The third column gives the 



CdBrj proportional to 100 parts of silver : 



*3.745G grm. CdBrj = 2.9715 grm. Ag. 



5.0270 " 3.9874 



*3.6645 ." 2.9073 



*3.7679 "" 2.9888 



*1.9225 " 1.5248 



2.9101 " 2.3079 



3.6510 " 2.8951 



3.9782 " 3.1551 



126.051 

 126.072 

 126.045 

 126.067 

 126.082 

 126.093 

 126.110 

 126.088 



Hence Cd= 112.19. 



Mean, 84.843, 



.026 



iProc. Amer. Acad., 17, 28. 1881. 



