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 (7) 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 ha 
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 weighe 
3.34 g ter deducting the 3.34 grammes of unde- 
composed mineral, from the 7.87 grammes in (.4,) there re- 
mained 4.53 grammes of the caleined mineral for the anal- 
Sis. ; ; 
_C. The two muriatic solutions (B) were mixed and evap- 
aare to dryness ; the dry mass was treated by water acid- 
u 
ated with muriatic acid; it was then moderately evapora- 
ted, again treated by water and filtered. Silex remained on 
the filter, which, after being washed and calcined, weighed 
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. eit 
E. The yellow solution (B) was saturated by mumatic 
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 alumme 0F 
4.53 of the mineral, or 13,002 per 100. 
