168 TWO NEW MINERALS. 



The above properties show the presence of water, carbonic 

 acid, lime, and uranium ; farther examination gave no evidence 

 of the presence of any other substance. 



The amount of this mineral in a state of purity was too 

 small to allow me to make as minute a quantitative analysis as 

 I should desire ; but, owing to the simplicity of its composition, 

 the true nature has been very nearly if not exactly made out. 

 The water was estimated by heating it to 400° Fah. ; the car- 

 bonic acid by what was lost in dissolving it in hydrochloric 

 acid in a small apparatus properly arranged ; to the acid so- 

 lution bicarbonate of ammonia was added, which redissolved 

 all the precipitate first found ; oxalate of ammonia when added 

 to this precipitated the lime (which was afterward estimated 

 as a sulphate) ; the solution filtered from this precipitate was 

 boiled and the uranium deposited itself as a double salt that 

 was heated to redness, and the oxide estimated in the form 

 of olive-colored oxide. (Peligot's atomic weight for uranium 

 was the one employed, 750 ; oxygen 100.) 



The mean of two analyses, one of 85 and the other of 65 

 milligrammes, is 



Atoms. Calculated. 



Water 45.2 20 45.5 



Carbonic acid 10.2 2 11.1 



Lime 8.0 1 7.1 



Peroxide of uranium.... 38.0 1 36.3 



101.4 100.0 



The composition of the mineral is represented by ti C+Ca C 

 +20 H. The pitchblende upon which the liebigite is found was 

 analyzed, and at some future time I may have occasion to al- 

 lude to this analysis with some remarks upon the salts of 

 uranium ; for the present suffice it to state that the pitchblende 

 contains lime associated with the oxide of uranium, a circum- 

 stance that, along with the tendency of oxide of uranium to 

 form double salts, accounts for the formation of both the lieb- 

 igite and medjidite. 



I have thought proper to give this double carbonate the 

 name of the distinguished chemist of Giessen, as a demonstra- 

 tion of the high value I set upon his memoirs and important 

 contributions to the science of chemistry in general. 



Liebigite I have also found in one of the European locali- 

 ties of pitchblende — namely, Johanngorgenstadt. The first 



