244 Analysis of Chromic Iron Ore. 
2. Before the blowpipe, it dissolves in a bead of borax or mi- 
crocosmic salt, exhibiting the characteristic reaction of oxide of 
chrome. ; 
3. Analysis—To obtain a proper specimen of the mineral for 
analysis, it was coarsely broken up and separated from the 
gangue, as far as practicable. It was then finely pulverized, and 
one gramme of it ignited-with carbonate of soda and caustic po- 
-tassa, in order to convert the oxide of chrome into chromate of 
tassa. 
4. The fused mass was digested with water and thrown upon 
.a filter, which separated the oxide of iron and that portion of the 
mineral which had not been decomposed, from the other constit- 
uent which passed through in solution. The filter was then 
treated with hydrochloric acid, which dissolved the iron, leaving 
‘the undecomposed ore on the filter. This was found to amount 
to .353. 
5. The solution of chloride of iron which passed through, was 
then digested with nitric acid, and the peroxide precipitated by 
ammonia. This amounted to .172. In a previous experiment, 
it was found to contain neither alumina nor magnesia. 
6. The solution obtained by the first filtration (4), was next 
neutralized by nitric acid, enough being added to precipitate and 
redissolve the alumina. The latter was then precipitated by bi- 
carbonate of soda and its weight found to be .1414. 
7. The remaining solution was now evaporated to dryness with 
carbonate of soda, and treated with water. The magnesia thus 
rendered insoluble, was separated and amounted to .090. 
8. In the solution from (7), there still remained the oxide of 
chrome, which was estimated by concentrating the liquid by 
evaporation and adding to it while boiling, hydrochloric acid and 
ohol. The chromic acid, thus converted into oxide of chrome, 
was precipitated by ammonia and separated on a filter. ‘The S0- 
lution passing through, still contained a small portion of oxide of 
chrome and was therefore evaporated to dryness and digested with 
water. The oxide of chrome thus rendered insoluble, was add 
ee that before obtained, and the weight of the whole amounted to 
4, 
“Ss: Conelusions.—The streak of the mineral being chocolate 
brown, it is difficult to say whether this color arises from the pro- 
toxide of iron or the brown oxide of chrome, a problem of exceed- 
