URANIUM. 31 



2 atoms peroxide of uranium 56 

 1 atom potash ... 6 



3 atoms water . . . 3-375 



65-375 



The preceding details contain the most satis- 

 factory of the experiments which I made upon 

 this very difficult metal. I consider them my- 

 self as proving that the atomic weight of uran- 

 ium is 26 ; that its protoxide weighs 27, and 

 contains 1 atom of oxygen ; while its peroxide 

 contains 2 atoms of oxygen and weighs 28. But 

 some time after these experiments of mine had 

 been concluded, I had an opportunity of seeing 

 a paper on the Oxide of Uranium and its Com- 

 pounds, by Professor Berzelius, which that 

 cellent chemist has inserted in the Memoirs of Berzelius 

 the Stockholm Academy for 1823. Berzelius is oxides of 

 of opinion that the oxygen in the protoxide of 

 uranium is to that in the peroxides as 2 : 3. But 

 I have not been able to perceive any thing in his 

 experiments from which this inference can be 

 legitimately drawn. He analyzed three salts of 

 uranium ; namely, potash sulphate of uranium, 

 potash muriate of uranium, and oxalate of ura- 

 nium. I shall here state the results of these 

 analyses. 



(1.) The constituents of potash-sulphate of 

 uranium he found as follows : 



uranium. 



