160 Re-examination of Microlite and Pyrochlore. 



in water, they were dried on paper. Weighed at 60° F., 10 grains 

 lost in pure water at that temperature 1850, which gives 5-405 

 as the sp. gr. of the specimen. 



The fragments were reduced to a fine powder, in an agate mor- 

 tar, and dried over sulphuric acid, at about 60° F. A platina 

 capsule, which had been recently ignited and cooled, contained 

 10 grains of the powder. After exposure to a bright red heat for 

 twenty minutes, and cooled to 60° over sulphuric acid, the loss 

 was 0-040. Exposed on the balance twelve hours, nearly the 

 original weight was found, from absorption of atmospheric vapors. 

 The microlite is therefore anhydrous. 



A. Ten grains of the mineral, in fine powder, had been igni- 

 ted, and were mixed with 200 grains of pure bisulphate of pot- 

 ash, in a large platina crucible. Heated to moderate redness, the 

 powder dissolved into a yellow clear fluid. After cooling the 

 crucible, water was added, and the whole again heated ; the clear 

 fluid resulting from the use of successive portions of water, being 

 passed through a prepared filter. The white powder which re- 

 mained was boiled in diluted hydrochloric acid, successive quan- 

 tities being used and passed through the filter. Boiling water 

 left undissolved a lighter, fiocculent powder, which was collected 

 on the filter. When sulphydrate of ammonia was added to this 

 powder, it rendered it dark colored, and finally black. Twelve 

 hours after, the sulphydric solution was removed, and the powder 

 washed in water. Hydrochloric acid rendered the powder nearly 

 white, and boiling water removed all traces of acid. After a co- 

 pious washing in water, the powder has a slight degree of solu- 

 bility. The filter and contents, dried, were heated red hot, cooled 

 over sulphuric acid to 60°. 7-900 of pure dry columbic acid 

 remained after deducting 0-004 ashes, left by filter. 



B. After all the acid liquors, from the columbic acid, had been 

 boiled, and their bulk greatly reduced by evaporation from a 

 flask, the sulphuretted solutions from the same were added, drop 

 by drop, so as to saturate the warm acid fluid with hydrosulphuric 

 acid. A slight white precipitate had appeared during the boiling, 

 it became darker colored, and was increased in bulk by a deposite 

 of sulphur. When the odor of hydrosulphuric acid had been 

 dissipated, the brown precipitate was separated from the clear 

 fluid, washed in water, and collected and dried. By heat, sul- 

 phur was burnt off, and the addition of nitric acid, and subsequent 

 ignition, left a white, heavy powder, weighing 0200. 



