322 Seybert’s Analysis of Chromat of Iron. 
mes ; the loss of weight in water then amounts to 0.13 
grammes on 8 grammes, or 1.625 per 100, 
B. The residue of the calcination (4) mixed with 16 
grammes of nitrate of potash, and 8 grammes of caustic pot- 
ash, was exposed to fusion at a red heat, in a silver crucible 
during one hour. The fused mass was treated by water, 
and the solution, when filtered, was of a bright yellow col- 
our. The matter on the filter was red, it was then treated 
by diluted muriatic acid, to dissolve the silex which had 
formed a silicate with the alumine, insoluble in potash. This. 
solution was decanted, and the residue was boiled with con- 
centrated muriatic acid, to dissolve the per-oxide of iron, 
The last solution was filtered, and the residue on the filter 
consisted of that portion of the mineral which resisted de-_ 
composition ; after being washed and calcined it weighed. 
3.34 grammes. After deducting the 3.34 grammes of unde- 
composed mineral, from the 7.87 grammes in (4,) there re- 
mained 4.53 grammes of the calcined mineral for the anal- 
sis. 
: C. The two muriatic solutions (B) were mixed and evap- + 
orated to dryness ; the dry mass was treated by water acid- 
ulated with muriatic acid; it was then moderately evapora- 
ted, again treated by water and filtered. Silexremained on 
the filter, which, after being washed and calcined, weighed 
0.48 grammes, on 4.53 grammes, or 10.596 per 100. 
D. The liquor (C) was treated by.an excess of caustic 
potash, and boiled during an half hour ; it was then filtered ; 
muriatic acid was added to the filtered solution, and by 
means of ammonia, was found to contain a mere trace of . 
alumine. ‘The residue on the filter, washed and calcined, 
weighed 2.09 grammes ; it was dissolved in muriatic  acid,... 
evaporated to expel the excess of acid, and treated by wa- 
ter ; the iron was then precipitated by ferruginous hydro~ 
cyanate of potash. The liquor was filtered, the alumine 
was precipitated from the filtered solution by ammonia, ° 
washed and calcined it weighed 0.459 grammes—then by 
difference we have 1.631 grammes of per oxide of iron on | 
4.53 grammes of the mineral, or 36.004 per 100. | 
E. The yellow solution (B) was saturated by muriatic 
acid, a precipitate of alumine was formed, which, washed 
and calcined, weighed 0.13 grammes, so that, with the alu- 
mine obtained in (D,) we have 0.589 grammes alumine on 
4.53 of the mineral, or 13,002 per 100. 
