276 M. Berzeliits on Uranium. [Apri l 



nish uraiiite, and that which I analyzed, to consist essentially of 

 phosphate of oxide of uranium. 



This statement of Mr. Phillips induced me to analyse the 

 Autun uranite anew. An examination by the blowpipe instantly 

 detected phosphoric acid, whose presence was so much the 

 more unlooked for by me, because when in my earlier analysis I 

 diluted the concentrated solution of the mineral in muriatic acid 

 with alcohol, with a view to the subsequent precipitation of the 

 lime by sulphuric acid, it did not become in the least turbid, 

 although one would have naturally expected, that the pliosphate 

 of lime should have precipitated. 



That so large a proportion of hme and oxide of copper should 

 constitute an accidental admixture in the mineral, when, as 

 being more powerful bases than oxide of lu'anium, they ought to 

 share with it the phosphoric acid, appeared to me extremely 

 unlikely : I thought it much more probable that the two mine- 

 rals are isomorphous double salts, composed of an equal number 

 of simple atoms, but in one of which the lime is replaced by 

 oxide of copper. With a view to ascertain this, I undertook an 

 analysis of both. 



(A.) Uranite from Autun. — It is very difficult to determine 

 the water of crystallization in this mineral with accuracy, partly 

 because in consequence of its foliated texture, it has a peculiar 

 tendency to absorb hygroscopic moisture, and partly because it 

 retains only by a weak affinity even that portion of water which 

 exists in it in a state of chemical combination. In an attempt 

 which I made to dissolve the mineral in boiling acetic acid, I 

 found that not a trace passed into solution, but it acquired by 

 this treatment the same brown colour which it possesses after 

 the water of crystallization has been expelled by ignition. When 

 dried in a pulverised state in a temperature of 68°, it gave in 

 many experiments between 14*4 and 15'33 per cent, of water: 

 without this previous preparation, it gave as much as 17 per cent. 

 The water thus expelled reacted as an alkali, and had the odour 

 of ammonia. It was not precipitated by nitrate of silver, but it 

 left by spontaneous evaporation traces of a crystallized salt, 

 which was probably fluale of ammonia, for the neck of the retort 

 was distinctly corroded in the place where the water had con- 

 densed at the commencement of the operation. I saturated 

 with muriatic acid, and evaporated to dryness, the water expelled 

 from three grammes of uranite, but the residue of sal ammoniac 

 was scarcely sufficient to produce a sensible alteration on the 

 balance. 



I analyzed the mineral in three different ways : — 



1. The ignited powder was dissolved in nitric acid, the solu- 

 tion was diluted with alcohol, and a mixture of sulphuric acid 

 and alcohol was added, so long as any gypsum precipitated the 

 gypsum was washed with alcohol, dried, ignited, and weighed. 



