21$ 
the compounds of chromium. 
binarseniate of chromium. It was tasteless, and insoluble in 
water. When heated to redness it became rose red, but on 
cooling the colour became a dingy buff. This salt was 
analyzed in the following way. 
Six grains by ignition lost 1*45 grains, which were consi¬ 
dered as water. 12 grains were dissolved in caustic potash, 
and the alkali being neutralized by muriatic acid, the green 
oxide of chromium was thrown down by carbonate of am¬ 
monia. The precipitate dried on the filter weighed 4*3 
grains: but by ignition the weight was reduced to 2*18 grains. 
Hence the constituents were 
Arsenic acid - - 6-92 or 15-8 
Green oxide of chrome 2-18 or 5 
Water > - _ 2-90 or 6*65 
12*00 
If we consider it as a compound of 2 atoms acid, 1 atom 
green oxide, and 6 atoms water, the constituents will be 
2 atoms arsenic acid - - 15*5 
1 atom green oxide - - 5 
6 atoms water - - - 6*75 
27-25 
numbers which approach very near the actual result of 
analysis. 
7, Chromate of chromium. 
When chromic acid is digested on hydrated green oxide of 
chromium, a solution takes place, and the liquid assumes a 
dark brown colour. When we dissolve as much of the oxide 
as possible, and evaporate the solution to dryness, a brown 
