4 URANIUM, ANTIMONY, CHROMIUM, c. 



ed a red insoluble matter, consisting chiefly 

 of iron, which was not particularly examined. 

 The solution in carbonate of ammonia being set 

 aside for a few days in a close vessel, a consi- 

 derable number of very fine rich yellow crystals 

 were deposited, consisting of four-sided right 

 prisms, with rectangular bases. This salt was 

 tasteless, and insoluble in water, and proved, on 

 examination, to be a compound of carbonate of 

 ammonia, percarbonate of uranium, and water. 

 It was analyzed in the following manner : 



lt 4 9'875 grains of the crystals were put into 



carbonate a small retort, and exposed to a heat not ex- 



of uranium. A 



ceeding 400, on the sand bath. There first came 

 over some moisture, and then carbonate of am- 

 monia sublimed. I did not succeed in weighing 

 the water and the carbonate of ammonia sepa- 

 rately, for the carbonate absorbed the whole of 

 the water, and became dry crystals ; but the total 

 loss of weight sustained by the salt was 18 grains. 

 The salt, by being thus deprived of its carbonate 

 of ammonia and water, had acquired a most 

 beautiful orange red colour. It still dissolved in 

 acids with effervescence, and therefore contained 

 carbonic acid. When strongly heated by a spirit 

 lamp, some water was disengaged, and some car- 

 bonic acid (mixed probably with oxygen gas) 

 and the peroxide of uranium was converted into 

 protoxide. It now consisted of black grains, 

 having considerable lustre. They were easily 



