24 URANIUM, ANTIMONY, CHROMIUM, c. 



the whole water and acid were driven of and till 

 the uranium was reduced to the state of protoxide. 

 It now weighed 27 grains, which, from what has 

 been already stated, is equivalent to 28 grains of 

 peroxide. 



(2.) 57*25 grains of the crystals of the same 

 salt were dissolved in water, and the solu- 

 tion being mixed with about 30 grains of car- 

 bonate of barytes, was digested in a retort till 

 it had become perfectly colourless : the whole was 

 then thrown on a filter, which retained a yellow 

 powder, consisting of the peroxide of uranium 

 arid the barytes, partly combined and partly 

 mixed. The liquid being evaporated to dryness 

 left 24-5 grains of nitrate of barytes, equivalent 

 to 10*023 grains of nitric acid. This is less than 

 li atom of nitric acid by 0*1 grain, or almost 

 exactly one per cent. The reason of this defi- 

 ciency I found (after some trouble) to be owing 

 to the filter employed containing some sulphate 

 of lime, which decomposed a little of the nitrate 

 of barytes ; for I found distinct traces of lime in 

 the filtered liquid, though neither the carbonate 

 of barytes nor the salt of uranium contained a 

 particle of that earth. It is evident, then, that 

 57*25 grains of the crystallized nitrate of urani- 

 um contain 10*125 grains of nitric acid, equiva- 

 lent to li atom of acid. 



(3.) The remainder wanting to make up the 

 original weight of the crystals, amounting to 



