URANIUM. ( J 



10. Tungstate of soda A yellow precipitate. 



11. Tartrate of potash O- 



12. Oxalate of potash O. 



Arfwedson says, that peroxide of uranium 

 is slightly soluble in water. Not having been 

 able to procure the oxide in a separate state, I 

 was unable to determine the point ; but I found 

 it impossible, by washing, to deprive the percar- 

 bonate of uranium of the. property of giving a 

 greenish yellow colour to water : hence, I con- 

 ceive that salt to be slightly soluble in water. 



3. M. Arf\vedson passed a current of dry hy- Reduction 



. i r> . , of uranium. 



drogen gas over hot protoxide 01 uranium, and 

 by this means reduced it to the metallic state. 

 The metal thus obtained was in crystals, having 

 nearly the form of regular octahedrons : they had a 

 strong metallic lustre and a reddish brown colour. 

 This metal may be exposed to the air in ordi- 

 nary temperatures without alteration ; but when 

 heated, it undergoes a kind of combustion, and 

 is converted into protoxide of uranium. Arf- 

 wedson made two experiments to determine how 

 much loss protoxide of uranium sustains when 

 converted in this way into metallic uranium. 

 He found that 



1-187 protoxide lost 0-042 

 1-468 0-052 



According to these experiments, 100 parts of 

 uranium combine, in order to be converted into 



