224 Mr. Chenevix’s Analysis of 
These salts agree with the generality of the known salts of 
iron ; all of which contain a greater quantity of oxide, as the 
oxide itself contains less oxygen. 
By boiling with nitric acid, it was easy to convert the green 
arseniate of iron into the red ; and such is the case with all 
the salts of green oxide of iron. As, during the course of 
these experiments, I had occasion to make some remarks upon 
the divers habitudes of this metal, which, as far as I know, have 
not all been observed, I shall terminate the whole of these ana- 
lyses (as I have already done that part of them which treats 
of arseniate of copper in all its known varieties) by simply 
stating what has occurred to me. 
I happened to boil some muriatic acid upon a greater quan- 
tity of iron than the acid could dissolve. I found a perfectly 
limpid and colourless liquor remain, which, nevertheless, was a 
solution of muriate of iron. This colourless liquor being decom- 
posed by arseniate of ammonia, the precipitate was of a greenish 
white, and soluble in a great quantity of water ; but, passing to 
,a much deeper green, quickly fell to the bottom. A prussiate, 
or a gallate, poured into the said solution, occasioned no change, 
till it had stood a considerable time exposed to the contact of 
the air. By potash, and by soda, a white precipitate was thrown 
down, which quickly assumed a green tinge; and that tinge 
increased so much as to become a very deep grass green, in a few 
minutes. Ammonia occasioned a white precipitate, which was 
redissolved by an excess of the precipitant The ammoniacal 
solution assumed the same greenish tinge, and speedily de- 
posited an oxide of iron, which was first of a deep green, but 
instantaneously became black, with some yellowish ochrey 
particles on the surface. If, however, these precipitations were 
