• URANIUM. 129 



uranic oxide and on the oxidation of uranous oxide. By 

 combustion of uranous oxide in oxygen he found in two ex- 

 periments that 100 oxide combined with 3.695 and with 

 3.73 oxygen. From the reduction of the green oxide he 

 found that 100 uranous oxide combine with 3.67 oxygen. 

 He deduces as the mean 3.688. Regarding uranous oxide 

 as the metal, Arfvedson calculated the atomic weight at 

 2711.36. [If the lower oxide is a protoxide, the data give 

 128.6 for O = 16.] The uranous oxide was prepared from 

 pitchblende by solution in aqua regia, precipitation of heavy 

 metals with hydrogen sulphide, precipitation with ammonic 

 hydrate, solution in ammonium carbonate to remove iron, 

 reprecipitation, heating to redness, washing with chlorydric 

 acid to remove impurities, and reduction in hydrogen. 

 {Poggend. Ann., 1, 1824, 254.) 



E. Peligot : 119.128 (O = 16) . 



In two experiments the amount of carbon in the acetate 

 •was found to be 11.27 and 11.3; mean 11.285. In one ex- 

 periment the uranic oxide was determined at 67.3 per cent. 

 [From these data the above value follows.] Peligot takes 

 120 or 750, C = 75. The preparation of the salt is not 

 given. Peligot mentions the oxalate and gives analyses, 

 but does not deduce an atomic weight from them. {Annul, 

 de Chim. et de Phgs., (3,) 5, 1842, 39.) 



J. J. Ebelmen : 118.86 (0 = 16) ; 742.875 (O = 

 100). 

 Ebelmen made six experiments on the reduction of the 

 oxalate to uranous oxide by hydrogen and heat. The value 

 follows with an extreme difference of 0.65 for C = 75 ; H 

 = 12.5. All the weighings were reduced to vacuum. To 

 obtain pure oxalate, the nitrate was precipitated by oxalic 

 acid and this preparation decomposed by heat. The oxide 

 thus obtained was digested with chlorhydric acid, washed, 

 dissolved in nitric acid, recrystallized, and precipitated with 

 oxalic acid. The oxalate was dried at 100°. According 

 to Rammelsberg the reduction of the oxalate is accompa- 

 nied by the separation of carbon which remains with the 

 oxide. {Annal. de Chim. et de Phgs., (3,) 5, 1842, 189.) 



Berzelius, Arfvedson, Marchand : 128.4 (0 = 16); 

 802.49 (O = 100). 



While Arfvedson was making his first determination, 

 Berzelius also made an experiment on the combustion of ura- 

 9 



