164 Description of Edwardsite. 
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 
time 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 A portion of the clear solution was withdrawn 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 
leposit 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 
mixed with a little zirconia. The solution from which the erystals 
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 
