URANIUM. 265 



Wertheim's* experiments were even simpler in character than those 

 of Ebelmen. Sodio-uranic acetate, carefully dried at 200, was ignited, 

 leaving the following percentages of sodium uranate : 



67.51508 

 67.54558 

 67.50927 



Mean, 67.52331, .0076 



The final results of Peligot'sf investigations appeared in 1846. Both 

 the oxalate and the acetate of uranium were studied and subjected to 

 combustion analysis. The oxalate was scrupulously purified by repeated 

 crystallizations, and thirteen analyses, representing different fractions, 

 were made. Seven of these gave imperfect results, due to incomplete 

 purification of the material; six only, from the later crystallizations, 

 need to be considered. In these the uranium was weighed as U 3 8 , and 

 the carbon as CO 2 . From the ratio between the C0 2 and U 3 8 the atomic 

 weight of uranium may be calculated without involving any error due 

 to traces of moisture possibly present in the oxalate. I subjoin Peligot's 

 weighings, and give, in the third column, the U 3 O 8 proportional to 100 

 parts of C0 2 : 



CO 2 . U. A & . Ratio. 



.456 grm. 4.649 grm. 319.299 



.369 " 4.412 " 322.279 



2.209 " 7.084 " 320.688 



.019 " 3.279 " 3 2I -786 



.069 " 3.447 " 322.461 



.052 " 3.389 " 322.148 



Mean, 321.443, .338 



From the acetate, U0 2 (C 2 H 3 2 ) 2 .2H 2 0, the following percentages of 

 U 3 8 were obtained : 



5.061 grm. acetate gave 3.354 grm. U 3 O 8 . 66.2715 per cent. 



4.601 " 3-57 " 66.4421 " 



1.869 " 1.238 " 66.2386 " 



3.817 " - 2.541 " 66.5706 " 



10.182 " 6.757 " 66.3622 " 



4.393 2.920 " 66.4694 ' " 



2.868 " 1.897 " 66.1437 



Mean, 66.3569, .038 



The acetate also yielded the subjoined percentages of carbon and of 

 water. Assuming that the figures for carbon were calculated from known 



* Journ. fur Prakt. Chem., 29, 209. 1843. 

 fCompt. Rend., 22, 487. 1846. 



