VANADIUM. 131 



C. Rammelsberg : about 120 (0 = 16). 



Determined in six experiments, undertaken at Berzelius' 

 suggestion, by treating uranous oxide with nitric acid and 

 sulphuric acid and weighing the sulphate. It is very diflB- 

 cult to weigh the uranous oxide which constantly increases 

 in weight. Two experiments were made on the green 

 oxide, which was prepared either by heating uranous oxide, 

 or the nitrate, in air. Two experiments were made on 

 magnesium uraniate by dissolving the compound in nitric 

 acid and heating to redness. The compound was found 

 unstable in character. One experiment was made by heat- 

 ing the double acetate of uranium and sodium and three 

 experiments by heating the double acetate of barium and 

 uranium. The results obtained varied from 633.17 to 

 753.76. Rammelsberg considers the determinations confir- 

 matory of Wertheim's and Ebelmen's. {Poggend. Ann., 

 66, 1845, 95.) 



E. Peligot : 120 (O = 16) ; 750 (0 = 100). 



Determined by combustion of the oxalate in a current of 

 air, both the carbonic acid and the green oxide of uranium 

 being weighed. At first Peligot got only 730 as the atomic 

 weight by this process, but by repeating the recrystalliza- 

 tion of the salt until determinations gave constant results, 

 he got a mean of 750. He says that he came to the same 

 value by comparing the amount of uranic oxide obtained 

 from the acetate with the weight of the salt employed. 

 {Paris Comptes Bend., 22, 1846, 487.) 



VANADIUM. 



Roscoe has determined the vapor density of vanadium 

 chloride. It agrees with an atomic weight of about 51. 

 {L. Meyer, I. c.) 



J. J. Berzelius : 52.4? (O = 16). 



Berzelius made four experiments on the relation between 

 the higher and the lower oxides of vanadium, three by re- 

 duction with hydrogen at a very high temperature and one 

 by oxidation. He supposed the higher oxide to have the 

 formula VO3, and the lower VO, and consequently got for 



