38 Whitney’s Chemical Examination 
in nitric acid or in aqua-regia. It gives a beautiful green 
solution, a small quantity of flocky silica separating. 
The analysis was conducted as follows : 
A portion of the mineral, carefully selected and freed from 
foreign matters, was pulverized and dried at 100° C. It was 
then dissolved by chlorohydric acid in a suitable apparatus, 
the loss of weight. being considered as carbonic acid. The 
silica separated by filtration was found to be pure when tested 
by the blowpipe, and was entirely soluble in carbonate of 
soda. In the solution filtered from the silica, sulphuretted 
hydrogen threw down a precipitate, at first dark brown and 
afterwards black, of sulphuret of lead, which was estimated 
as sulphate of lead by oxidizing with nitric acid. The filtered 
solution was then digested till it no longer smelt of sulphur- 
etted hydrogen, and oxides of uranium and iron and alumina 
precipitated by causticammonia. The precipitate was washed 
with water to which chloride of ammonium had been added, 
and then taken moist from the filter, and re-dissolved. in 
- chlorohydric acid. In this solution oxide of iron and alumina 
were precipitated by carbonate of ammonia, the oxide of 
uranium remaining in solution, and care being taken that the 
solution should be quite dilute, in order that the iron might be 
entirely precipitated. The oxide of iron and alumina were 
separated by caustic potash. In the solution filtered from 
these substances, the uranium was precipitated by adding 
chlorohydric acid to supersaturation, boiling, to expel all the 
carbonic acid, and then adding ammonia. 
In the solution from which the precipitate by ammonia, of 
uranium, iron and alumina had been separated, the lime was 
thrown down by ammonia and oxalic acid. The filtered 
solution was evaporated to dryness, and the ammoniacal salts 
driven off by ignition, when there remained traces of mag- 
nesia and manganese. 
_ "The water was estimated by ignition in a bulb-tube, and 
collecting the water driven off in a weighed chloride of cal- 
cium tube. The mineral does not, however, part with any of 
