M6 PREPARATION GF THE PERCHLORIl>E OP IRON. 
liquid is evaporated in the atmosphere charged with humi- 
dity, it is decomposed when the salt has reached a certain 
degree of concentration, hydrochloric acid is disengaged, 
and sesquioxide of iron precipitated. It must be stirred 
with a glass spatula during the whole time of evaporation, 
which is continued until the liquid no longer disengages 
any perceptible vapors of hydrochloric acid, and a drop 
solidifies on cooling. When it has reached this point, the 
chloride is poured into perfectly dry phials, provided with 
good corks ; but from this chloride becoming very hard, 
it is difficult to remove it from the phials. To obviate this 
inconvenience, M. Soubeiran, who had the kindness to re- 
peat the process, advises its being poured on to a slightly- 
greased plate, which is immediately covered by another 
plate, and joined to the first by means of a little luting. 
After four-and-tvventy hours the plates are separated, the 
chloride broken into pieces, and immediately transferred in- 
to well-dried bottles, which should be corked with great care. 
The perchloride of iron, prepared in this manner, pos- 
sesses a dark yellowish-red color, no odor, but a very styp- 
tic taste. It is excessively and entirely soluble in water; 
the solution, which is of a beautiful golden yellow, pre- 
serves for an indefinite length of time, exposed to the air, 
without becoming turbid; it is likewise very soluble in 
alcohol and ether. Exposed to the air, it rapidly absorbs 
moisture, which at first it solidifies, but subsequently it de- 
liquesces, and it is therefore necessary to keep it in dry and 
well-closed bottles. This chloride has the great advantage 
of keeping for a long time without being decomposed, ow- 
ing without doubt to the small quantity of water it con- 
tains; thus the samples which I possess are as good at 
present as they were eight months ago, immediately after 
their preparation. 
To ascertain the quantity of water which it contains, I 
took four samples of the chloride, one of which had been 
prepared by M. Soubeiran and the other three by myself, I 
