1825.] M. BerzeUits on Uranium. 275 



and as uranium was at that time undiscovered, he was induced 

 by his experiments to consider it a compound of muriatic acid, 

 alumina, and oxide of copper. Hence Werner apphed to it the 

 name of chalcohte. 



Klaproth, who examined the mineral in 1790, found that its 

 solution in nitric acid is not precipitated by a solution of silver, 

 and that it contains oxide of uranium, which he had then recently 

 discovered, together with a quantity of oxide of copper, which, 

 however, he regarded as accidental, because in other specimens 

 it was totally wanting. The mineral was now regarded as a 

 crystallized oxide of uranium. 



Gregor afterwards, iu 1805, examined a uran mica, in which, 

 besides oxide of uranium, he found lime, oxide of lead, and sihca; 

 and in 1815 a green variety, from which he separated 74*4 per 

 cent, of oxide of uranium containing a trace of oxide of lead, 8'3 

 per cent, of oxide of copper, and 15'4 per cent, of water. The 

 oxide of copper he considered by far too abundant to constitute 

 a mere accidental ingredient. 



More lately, in 1819, I undertook an examination of the 

 uranite from Autun, in which I found so considerable a propor- 

 tion of lime, that it was impossible to regard it as an accidental 

 constituent. The result of my analysis was lime 6'87, oxide of 

 uranium 72"15, oxide of manganese and magnesia 0*80, water 

 15-7, gangue 2*5 : hence I concluded that the mineral is a ura- 

 nate ot lime with water of crystallization. As I did "not possess 

 a sufficient stock of the Cornwall uranite for a regular analysis, I 

 examined it before the blowpipe, and finding that it contained 

 copper, that it gave off an odour of arsenic in the reducing 

 flame, and that the globule of copper obtained with the assist- 

 ance of soda was white and brittle, I concluded that the green 

 colour is occasioned by the presence of arseniate of copper. 



Towards the close of 1822, Mr. Phillips discovered phospho- 

 ric acid in the Cornwall uranite, while treating it with a caustic 

 alkali, in order to separate the ar&enic acid, which I had stated 

 to constitute one of its ingredients. This induced him to make 

 a new analysis of the mineral, by which he found it composed of 

 oxide of copper 9*0, oxide of uranium 60*0, phosphoric acid 

 16'0, silica (J*5, water 14*5. He found also, that although the 

 mineral is not altogether free from arsenic acid, the proportion 

 of this ingredient is so inconsiderable, that it may be safely 

 neglected. In consequence of his having employed erroneous 

 numbers for the basis of his calculations, Mr. Phillips was led 

 to regard the mineral as a mixture of 72*2 neutral phosphate of 

 uranium with 12-3 phosphate of copper, by which there still 

 remained unappropriated an excess of phosphoric acid. The 

 water he regarded as shared between the two phosphates iu 

 such a manner, that the salt of uranium contains 3, and the salt 

 of copper 2 atoms. On the whole, he considered both the Cor- 



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