278 



M. Berzelius on Uranium. 



[April, 



was mixed with alcohol and an additional quantity of sulphuric 

 acid, by which means the whole of the hme was obtained in the 

 state of sulphate. From the acid alcoholic liquid, diluted with 

 water, subphosphate of ammonia precipitated a minute portion 

 of a mixture of magnesia and oxidule of manganese, in the form 

 of the double animoniacal subphosphates. 



3. The barytes was separated from the nitric solution of the 

 ignited mineral by sulphuric acid : the liquid was then concen- 

 trated, and the lime was precipitated by a mixture of sulphuric 

 acid and alcohol. The hltered solution was freed from alcohol 

 by evaporation, and decomposed by ammonia. The precipitate, 

 which was a double subphosphate of oxide of uranium and 

 ammonia, was very cautiously calcined (in a high temperature 

 its colour is partially converted to a green*), weighed, and 

 decomposed by ignition with potash ; and the oxide of uranium 

 was afterwards isolated by the process which has been already 

 described. Its weight, deducted from that of the calcined 

 phosphate, indicated that of the phosphoric acid, I found to my 

 surprise that subphosphate of ammonia still detects the presence 

 of magnesia and oxidule of manganese in a liquid from which 

 phosphate of oxide of uranium has been precipitated by 

 ammonia. 



The following are the results of three analyses of 100 parts of 

 the ignited uranite, performed according to the three foregoing 

 methods : 



A. 



Barytes 1-84 



Lime (j-75 



Magnesia 1 



Oxidule of mangan. J 

 Oxide of uranium . . 71-25 

 Phosphoric acid. .. 16-75 



Oxide of tin 0-06 



Gangue 3*35 



100-00 



100-35 



97-42 (?) 99-39 



Admitting that the mean of these three analyses approaches 

 nearest to the truth, and that the water amounts to 14-9 per 

 cent, (which however includes the fluoric acid and ammonia), it 

 will follow that 100 parts of uranite are composed of 



This decomposition docs not take place with tlie double subsalt of lime. 



