164 Description of Edwardsiie. 



in the same solution. A portion of the white precipitate was heated 

 on platinum foil before the blowpipe ; it easily suffered fusion, and 

 on cooling crystallized in the form of an irregular dodecahedron. 

 The mineral was accordingly inferred to be a phosphate. 



The matter undissolved by the acetic acid was digested for some 

 lime with hydrochloric acid. An odor of chlorine was evolved, at- 

 tended with a very slow solution of the substance, circumstances 

 which, taken along with the color it assumed, led me to suspect the 

 presence of cerium. A portion of the clear solution was withdrawn 

 and evaporated to dryness, after which water was afFused and am- 

 monia added. The precipitate occasioned after washing, was di- 

 gested in oxalic acid, and the solution separated from the undissolved 

 portion. The latter on being ignited and crushed to powder had a 

 tile red color, and was inferred to be nearly pure peroxide of cerium. 

 The solution gave on the addition of hydrosulphate of ammonia a 

 faint black precipitate, which was taken for sulphuret of iron. An- 

 other portion of the hydrochloric solution, containing crystals of sul- 

 phate of potassa, was set aside for twenty four hours, when a fine 

 white grained deposit had formed on the bottom of the vessel. This 

 deposit was separated, dissolved in hot water, and decomposed by 

 soda. The precipitate was washed and ignited. It had a tile red 

 color, and was regarded as peroxide of cerium, either pure or only 

 raixed with a little zirconia. The solution from which the crystals 

 had been precipitated was tested for yttria by ammonia, but no cloudi- 

 ness in the fluid was perceived. 



Being satisfied by the foregoing experiments that the mineral was 

 essentially a phosphate of cerium, I did not, on account of the scar- 

 city of the substance, carry my examinations any farther previous to 

 entering upon the analysis. 



Quantitative examination. — A. 45 centigrammes of the mineral 

 were mingled with two grammes of carbonate of soda, and heated in 

 a platinum crucible nearly to whiteness for an hour. The matter 

 suffered complete fusion, having shrunk into a very compact mass, 

 with a radiating structure and a grayish white color, with occasional 

 tinges of yellow. 



B. Water was repeatedly boiled upon the mass, until the whole 

 was removed from the crucible. The alkaline solution was separated 

 from the insoluble matter by means of the filter, and saturated with 

 acetic acid. 



