362 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Series IV., where both the weight of tlie residue and the silver bromide 

 obtained from it were determined. Since, however, the use of this 

 analysis causes the average of Series IV. to approach within one part in 

 thirty thousand of the average of Series V. and VI., we may safely 

 assume that the rather meagre data represent with great exactness the 

 real weight of the impurity contained in this Sample I. of cobaltous 

 bromide. In Series V. and VI. the residues were weighed directly, so 

 that this factor was not needed. Below are given the results of the first 

 two series of analyses. 



THE ATOMIC WEIGHT OF COBALT. 



O = 16 ; Br = 79.955. 



Fourth Series (Preliminary). CoBfj : Co. 



Fifth Series. CoBfo : Co. 



* From the residue in Series Y., analysis 5, was obtained 0.01210 gram of 



