Brush and Dana—Fairfield County Minerals. 39 
n examination of a parallelopided cut with its edges par- 
allel to the three axes of elasticity (crystalline axes) showed a 
very distinct trichroism. The axial colors are as follows: 
For vibrations parallel to a (that is) yellowish. 
b (thatis a) deep pink. 
¢ (that isc (vert.)) faint pink to nearly colorless. 
with the sodium phosphate. The residue of oxides of iron 
and manganese was dissolved in hydrochloric acid and the 
iron separated from the manganese by means of a basic ace- 
tate precipitation. To insure the complete separation of the 
alumina from the iron, the precipitate of basic acetate of iron 
was boiled with sodium hydroxide, the solution filtered off 
and added to the solution from the fusion, the oxide of iron 
was then dissolved in hydrochloric acid, the iron precipitated 
with ammonia and weighed as iron sesquioxide. The iron was 
then dissolved in hydrochloric acid, evaporated with nitric acid 
and ammonium molybdate added to precipitate any phosphoric 
acid which might not have been separated by the sodium car- 
bonate fusion. In this case there was a complete separation. 
From the filtrate from the basic acetate precipitation, manga-— 
nese was precipitated by means of bromine, the precipitate dis- 
solved in hydrochloric acid, the manganese again precipita 
as ammonio-manganese phosphate and weighed as brrophus: 
hate. From the filtrates from the precipitation by bromine, 
ime was thrown down as oxalate. The solutions containing 
the alumina were acidified with hydrochloric acid, boiled to 
expel carbonic acid, and aluminum phosphate precipitated 
by means of ammonia; the precipitate was filtered, washed, dis- 
solved and again precipitated and weighed as aluminum phos- 
phate. As this precipitate is not constant in composition, after 
weighing, it was dissolved in nitric acid and the phosphoric 
d separated by means of ammonium molybdate. The phos- 
phoric acid was determined and deducted from the weight of 
the aluminum phosphate. , 
he sodium wis Sélertainad by precipitating the bases from 
