#819.] the Oxygenized Acids and Oxides. 7 
make their appearance at the bottom of the vessel, ascend, and 
burst at the surface of the liquid. This even happens when the 
acid is only once oxygenized. Suspecting that this slow decom- 
position might’ proceed from the action of light, I filled almost 
completely a small flagon with acid, and after corking it, turned 
itupside down, and placed it in a dark place. Aft@r some hours, 
an explosion took place. The acid contained more than 30 
times its volume ; yet when this same acid was put under the 
exhausted receiver of an air-pump, it allowed but a small quan- 
tity of the gas which it contained to be disengaged. 
Hitherto I had imagined that the whole of the oxygen was 
disengaged from the muriatic acid at a temperature below ebul- 
lition; but this is not the case. After boiling oxygenized muriatic 
acid for half an hour, I still found oxygen in it. 
It is by means of the oxide of silver that we can demonstrate 
the presence of oxygen in oxygenized muriatic acid which has 
been boiled. Scarcely does it come in contact with it but oxygen 
is suddenly disengaged. This oxide enables us to determine 
with facility the quantity of oxygen contained in oxygenized 
mauriatic acid. The analysis requires only a few minutes. Take 
a graduated glass tube, fill it almost entirely with mercury, pour 
into it a determinate volume of acid, fill the tube completely 
with mercury, and turn it upside down in the mercurial trough. 
Let up into the acid an excess of oxide of silver suspended in 
water. Immediately we see disengaged, and may read off on 
the tube, the quantity of oxygen contained in the acid. We can 
estimate the quantity of chlorine: and, of consequence, the 
muriatic acid, by decomposing a part of the acid itself by means 
of nitrate of silver.* ; 
The disengagement of oxygen from the oxygenized muriatic 
acid is so rapid, that it would be dangerous to operate upon a 
weak acid, which contained 26 or 30 volumes of oxygen. The 
tube would probably escape from the hands of the operator, or 
would break. Accordingly nothing can equal the effervanoctied 
which takes place when we plunge a tube containing oxide of 
silver and agitate it in some grammes of the acid of which we 
have just spoken. As that acid is immediately destroyed, the 
oxygen is restored to its liberty, and escapes with violence, 
driving the liquid before it. 
When the most oxygenized muriatic acid is poured upon the 
sulphate, the nitrate, or the fluate of silver, no effervescence 
takes place. All the oxygen unites with the acid of the salt, 
while the muriatic acid forms with the oxide of silver water and 
a chloride. 
I have already made several attempts to ascertain if the 
oxygenized acids be capable of taking up so much the more 
* Having just observed that in this experiment there is a portion of the oxygen 
of the oxide of silver disengaged, it is obvious that we must take an account of this 
quantity to get an accurate result, Seenext paper. 
