378 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



published, are radically defective. Assuming N = 14.04, Aloy gives the 

 following values for uranium : 



239.3 



239.4 



239.6 



239.3 



239.4 



239.5 



239.4 



239.4 



Mean, 239.412, ± .0235 



If N = 14.0101, this reduces to 11 = 238.902. 



The important memoir by Richards and Merigold ^ begins with, a 

 careful criticism of former determinations. In Alov's work, they show 

 that the residual oxide probably contained some unexpelled nitrogen, 

 and they also point out the difficulty of exactly measuring small volumes 

 of gas. Their own work was based upon careful analyses of uranous 

 bromide by the best established methods, and their results, with vacuum 

 weights, are as follows. First, analyses to determine the ratio 

 4AgBr : UBr, : 



Preliminary Series. 



' Proc. Amer. Acad., 37, 365. 1902. 



