ATOMIC WEIGHTS 



379 



The two ratios, combined, give the cross ratio Ag: Br : : 100 : 7-l:.074. 



Oechsner de Coninck/ in order to establish the molecular weight of 



uranyl oxide, reduced UOoBro by heating. His results were as follows : 



Mean, 63.080, ± .0805 



Hence U= 241.1. 



In a second brief paper ^ he gives three reductions of the chloride, 

 UO2CI0, by heating in hydrogen : 



Mean, 79.152, ± .0197 



Hence 17 = 237.24. 



These determinations are of no real importance, and are included in 

 this discussion merely for the sake of completeness. Summing up, the 

 following ratios are now available for uranium : 



(1). Per cent. UO, from uranyl oxalate, 71.782, ± .019 

 (2). 6CO,:U30s: :100:321.443, ± .338 



(3). Molecular weight of uranyl acetate, 425.861, ± .1050 

 (4). SUO^iUsOs: : 100: 103.9276, ± .0003 



(5). Per cent. Na,UA, from UO„.Na(C2H30,)3, 67.549, ± .0025 

 (6). N:U: : 14.04: 239.412, ± .0235 

 (7). 4AgBr:UBr4: : 100: 74.295, ± .0027 

 (8). 4Ag:UBr,: :100:129.328, ± .0066 

 (9). U03Br2:U02: : 100: 63.080, ± .0805 

 ( 10 ) . U0,C1, : UO, : : 100 : 79.152, ± .0197 



To reduce these ratios we have — 



Ag =107.880, ±.00029 C = 12.0038, ± .0002 



CI = 35.4584, ± .0002 N = 14.0101, ± .0001 



Br = 79.9197, ± .0003 Na = 23.0108, ± .00024 



H = 1.00779, ± .00001 



1 Bull. Acad. Belg., Classe des Sciences, 1907, 1041. 



- Ibid., 1908, 163. In another paper, Compt. Rend. , 147, 1477, Oechsner de Coninck describes 

 attempts to determine the atomic weight of chlorine by reductions of UO2CI2. His results have 

 no value and need not be considered here. 



