130 ATOMIC AVEIGHT DETERMINATIONS. 



nous oxide getting 103.685 urauic from 100 uranous oxide. 

 Marchand {Erdmann's Journ. fur Prak. Chem., £3, 1841, 

 498) got in the same way 103.668. The average of the 

 combustion experiments of all three chemists is 103.694, 

 whence Berzelius calculates the value. {Berzelius' Jahres- 

 bericht, 2S, 1842, 113.) Peligot and Rammelsberg, as well 

 as Marchand, point out faults in this method, such as the 

 probable condensation of hydrogen in the protoxide and 

 the tendency to form higher oxides. {Poggend. Ann., 59, 

 1843, 4.) 



C. Rammelsberg. 



This chemist made experiments on the reduction by 

 hydrogen of the green oxide, prepared in various ways, 

 and got results varying from 580.4 to 767.6 for O = 100. 

 [Poggend. Ann., 59, 1843, 9.) By precipitation of uranous 

 chloride with silver he reached the number 787.5 for CI =: 

 442.65. The chlorine contents found varies in three ex-, 

 periraents from 73.89 to 74.46. The chloride was prepared 

 by heating uranous oxide in an atmosphere of chlorine. 

 {Poggend. Ann., 55, 1842, 321.) 



J. Wertheim : 119.4^ (0 = 16) ; 746.36 (0 = 100). 



Determined by three experiments on the decomposition 

 of the double acetate of uranium and sodium. The mean 

 loss of acetic acid by heating the salt to redness was 32.477 

 per cent.; extreme difference, 0.036. The number follows 

 for C = 75, H = 6.25, Na = 390.9. [In Poggend. Ann., 57, 

 484, an abstract is given of a paper read before the academy 

 (of Berlin ?) by Mitscherlich, in which he states that Wert- 

 heim's experiments above described give 740.512. Berze- 

 lius in his Jahresbericht, 23, 137, makes or quotes the same 

 statement, so also does Rammelsberg, Poggend. Ann., 59, 

 4, and it has been repeated elsewhere. I have recalculated 

 the data given by Wertheim and find the results correctly 

 deduced in his own report. For Na = 23.043 (Stas) ; the 

 data give U = 119.53.] The salt was prepared from urani- 

 nite by solution in nitric acid, precipitation with hydrogen 

 sulphide, evaporation of the filtrate to dryness, solution 

 in hot water, crystallization and recrystallization, heating 

 the crystals to drive off nitric acid, solution in acetic acid, 

 digestion with sodium carbonate and recrystallization. 

 {Erdmann's Joiirn. fiir Prak. Chem., 29, 1843, 209.) 



