URANIUM. 29 



3 atoms oxalic acid 13-5 



1 atom peroxide of uranium 28 



41-5 



The solution being evaporated let fall yellow 

 crusts of the oxalate, which had little taste, and 

 were scarcely soluble in cold water. But they 

 dissolved in hot water ; the solution had an as- 

 tringent taste, and reddened vegetable blues. 



10. Urania te of potash. Arfwedson having Analysis of 



. . _ . uraniate of 



shown that peroxide or uranium possesses the potash, 

 properties of an acid, I wished to see whether I 

 could form a definite compound of this oxide 

 and potash. For this purpose I digested on the 

 sand bath a quantity of percarbonate of uranium 

 in a pretty strong solution of caustic potash ; 

 the yellow colour of the powder was speedily 

 changed into a deep orange, bordering on red, 

 and its volume diminished. The caustic potash 

 was poured off after two hours' digestion, and a 

 fresh portion poured on, which was allowed to 

 digest on the powder for twenty-four hours. 

 The uraniate was then collected on a filter, 

 washed, and dried in a low heat. I now exa- 

 mined it in the following manner. 



(1.) Nineteen grains of it were dissolved in 

 nitric acid in a balanced glass vessel. There 

 was a slight effervescence, and the loss of weight 

 amounted to O3 grain ; this loss was occasioned 

 by the escape of some carbonic acid gas. 



