58 Mr. R. Phillips's Analysis of Uranite. [J a n . 



from the yellow, except in containing a little of the oxide of 

 copper." This opinion is confirmed by the identity of the 

 crystalline form already noticed ; Mr. Gregor stales, however, 

 that he had not a sufficient quantity of the crystals to allow of 

 subjecting them to a rigorous examination. Since this period, 

 Mr. Greo-or has given an analysis of the green crystals in the 

 fifth volume of the Annals, according to which they consist of 



Oxide of uranium, with a trace of oxide of lead . . 74-4 



Oxide of copper 8-2 



.Water 15-4 



Loss 2*0 



100-0 



M. Berzelius, inhis Nouveau Systeme Mine ralogi que, has given 

 an analysis of the uranite of Autun: he says, "I have found that 

 this mineral is a compound of oxide of uranium, with lime and 

 water ; in fact, that it is a true salt with a base of lime in which 

 the oxide acts as an acid." He further states, that the oxygen 

 of the uranium is three times, and that of the water six times, 

 the oxygen of the lime ; there is, however, he observes, a slight 

 excess of oxide of uranium and of water. The results of this 

 analysis are thus stated : 



Lime 6-87 



Oxide of uranium 72*15 



Water 15-70 



Oxide of tin 0*75 



Silica, magnesia, oxide of manganese. 0-80 

 Matrix 2-50 



98-77 



" The same mineral," continues Berzelius, " is met with in 

 Cornwall, but it is of a very fine deep-green colour ; this colour 

 is owing to the presence of a certain quantity of arseniate of 

 copper, which is an accidental admixture. When this uranite 

 is treated with soda by the blowpipe, it gives white metallic 

 globules, composed of arseniuret of copper." 



With the intention of procuring some peroxide of uranium, I 

 dissolved a quantity of the green uranite in nitric acid ; the 

 oxide of uranium was precipitated by ammonia, and the oxide 

 of copper dissolved by excess of it. In order to free the oxide of 

 uranium from any arsenic acid which it might contain, I boiled 

 the precipitate in a solution of potash; on adding a portion of the 

 filtered solution to nitrate of silver, an abundant yellow preci- 

 pitate was formed, which had the appearance of arsenite of 

 silver ; but as arsenious acid does not, I believe, exist in nature 

 combined with any metallic oxide, and as also the mineral in 



