the compounds of chromium. 211 
matter weighed 18*75 grains. It was a fine chromium green 
powder, tasteless, and insoluble in water. When heated to 
redness it smoked, gave out the smell of muriatic acid, and 
became greenish black. The weight was reduced to 12*72 
grains. 
The water digested over this salt being examined by re¬ 
agents, no phosphoric acid could be detected in it. Conse¬ 
quently the 12*72 grains of phosphate of chromium contained 
all the phosphoric acid employed in the experiment. It is 
clear that the phosphate formed was composed of 
Phosphoric acid - - 7*46 or 7*09 or 2 atoms. 
Green oxide of chrome 5*26 or 5 or 1 atom. 
12*72 
Water - _ _ 6-03 or 5*68 or 5 atoms. 
The salt was a biphosphate, and obviously composed of 
2 atoms phosphoric acid - 7 
1 atom green oxide - - 5 
5 atoms water - - - 5*625 
i 7"625 
The slight excess of water was probably owing to the pre¬ 
sence of a little muriatic acid in the salt before it was exposed 
to a red heat. 
I did not succeed in my attempts to obtain a neutral phos¬ 
phate of chromium. The biphosphate is soluble in phosphoric 
acid, and forms a deep green, sweet, and acidulous liquid; 
but the acid does not dissolve an atomic quantity; at least I 
did not succeed in obtaining such a solution. It is not unlikely 
that a quadro-phosphate of chromium exists. 
