231 
the Arseniates of Copper, and of Iron. 
surprise, when, upon the first affusion of water, I saw the liquor 
become turbid and milky, and a very abundant heavy precipi- 
tate, of a white colour, fall to the bottom. 
Struck with the novelty of this appearance, I proceeded to 
collect as much of the substance as I could, in order to give 
it a thorough examination. For this purpose, I decanted the 
supernatant liquor, and continued to wash the precipitate. 
Upon every subsequent addition of water, I perceived that 
the precipitate lost a little of its whiteness, and drew towards 
an orange colour, not unlike the precipitates of platina, I 
soon found, therefore, that by this method I had no chance of 
obtaining, in a permanent and constant state, this muriate of 
copper, fit to be subjected to experiments proper to determine 
its internal nature and proportions. I then attempted to make 
use of alcohol, as precipitant, instead of water ; but I found the 
salt to be soluble in it, when the excess of acid necessary 
for its solution in water was present. Nor was I more success- 
ful, when, after having precipitated by water, I washed with al- 
cohol ; for the colour of the salt passed gradually from very 
white to a shade of orange ; less rapidly, it is true, in this case, 
but still so as to convince me, that I could not even thus pro- 
cure, in a state constantly similar, the salt I wished to examine. 
The only conclusion which all these experiments entitled me 
to draw, was that, in the first instance, water precipitated the 
muriate of this particular oxide of copper from its solution, but 
in a manner very different from that in which muriate of anti- 
mony, of bismuth, and some other metallic salts are acted upon. 
When into either of these muriates water is poured, a preci- 
pitate ensues, but it retains a very small portion of acid, if any ; 
whereas, in the case before us, it is a salt, and not an oxide of 
