Chemical Examination of Microlite. 339' 



E. ir5 centigrammes of the ignited mineral (B) were mingled 

 with 25 centigrammes of carbonate of potassa and heated to white- 

 ness for fifteen minutes. An imperfect fusion in the mixture was 

 the result. The porous mass assumed a pale bluish color. On the 

 addition of water, it became obvious that but a small portion of the 

 mineral had suffered decomposition. It was accordingly treated to a 

 new portion of the alcaline carbonate, and the crucible maintained 

 at a white heat for one hour. The fusion was now complete, and 

 the mass on cooling assumed a delicate sky-blue color. It was sep- 

 arated from the crucible by means of dilute acetic acid. 



F. The clear acetic solution gave no precipitate with acetate of 

 lead, thereby evincing the absence of phosphoric acid. 



G. Hydrosulphate of ammonia occasioned no troubling in the 

 acetic solution, from which the absence of iron was inferred. 



H. Oxalate of ammonia produced a cloudiness and a precipitate 

 in the acetic solution ; which was occasioned, as afterguards became 

 more apparent, from the presence of lime and yttria. 



I. The matter undissolved by acetic acid was digested for some 

 time with hydrochloric acid. A part of the solution, on being treat- 

 ed with the hydrosulphate of ammonia, yielded a black precipitate 

 which was insoluble in excess of the precipitant. It vi'as therefore 

 attributed to protoxide of uranium in the mineral. 



J. The residuum left by the hydrochloric acid in I, was digested 

 in hydrosulphate of ammonia. The solution was separated by the 

 filter, and evaporated to dryness. Ammonia was added to the resi- 

 duum and the clear solution treated with nitric acid ; a yellow pre- 

 cipitate fell. Tungstic acid is consequently an ingredient of mi- 

 crolite. 



' K. Another portion of the hydrochloric solution (I) was treated 

 with, a crust of sulphate of potassa crystals and set aside for twenty 

 four hours, at the expiration of which time a perceptible accumula- 

 tion of fine white grains was perceived, thus proving the presence of 

 one or more earths, forming double salts with sulphate of potassa. 



L. The residuum after digestion in hydrosulphate of ammonia, 

 (J,) was fused with six times its weight of carbonate of soda and 

 heated to whiteness. To the clear solution obtained by boiling wa- 

 ter on the fused mass, nitric acid was added. A heavy white pre- 

 cipitate fell ; nitrate of silver also threw down a precipitate, which 

 was insoluble in nitric acid. Tartaric acid produced no troubling in 

 the aqueous solution. Columbic acid was thus found to be a con» 

 stituent of the mineral. 



