URANIUM. 19 



1 atom carbonic acid . 2-?5 

 1 atom peroxide of uranium 28-00 

 1 atom water . 1-125 



31-875 



I took 318'7<5 grains of this carbonate (equiva- 

 lent to 10 atoms peroxide of uranium) and 

 poured over it 183'75 grains of sulphuric acid of 

 the specific gravity 1*847 (equivalent to 30 

 atoms acid) and a considerable quantity of 

 water, and digested the mixture on the sand 

 bath till a complete solution was obtained. I 

 thus employed twice as much acid as the re- 

 quisite quantity. The reason was, that the so- 

 lution goes on very slowly unless there be an 

 excess of acid. To this solution I added 110 

 grains of sulphate of potash (equivalent to 10 

 atoms of the salt) previously dissolved in water, 

 and evaporated the mixture. The triple sul- 

 phate was deposited to the very last from this 

 solution n a state of purity, without any crystals 

 of sulphate of potash ever appearing, showing 

 clearly that in the triple salt there exists just an 

 atom of each basis. When the liquid was re- 

 duced to a very small quantity, I was obliged to 

 employ a higher temperature to continue the 

 evaporation. The consequence was, that at last 

 the salt began to acquire a greenish tinge. This 

 effect was doubtless owing to the redundant sul- 

 phuric acid present. On account of this change, 



B2 



