36 Dr. Murray’s Experiments on [Jan 
ortion of water contains 29 of oxygen with 3°8 of hydrogen. 
here is present, therefore, exactly the quantity of oxygen 
which the metal requires to combine with the acid; and no 
water remains above this ; or it may be illustrated under another 
point of view. Muriatic acid gas is composed of oxymuriatic 
gas and hydrogen. A metal acting on it must attract the oxy- 
muriatic acid—that is, the muniatic acid and oxygen, and liberate ' 
the hydrogen. No water, therefore, ought to appear more on 
this theory than on the other ; but the real products in both must 
be a dry muriate, or chloride, and hydrogen gas. ‘In the action 
of ignited metals on muriate of ammonia, it is equally evident, 
on the same principle, that no water ought to be obtamed. How 
then is the production of water to be accounted for ? 
Though the water obtained in these experiments eannot be 
derived from hygrometric vapour in the gas, there is another 
view under which it may be regarded at present as an adventi- 
tious ingredient. The acid having a strong attraction to water, 
may be supposed in the processes in which it is usually prepared, 
to retain a portion not strictly essential to its constitution as 
muriatie acid gas, but still chemically combined—that is, com- 
bined with it with such an attraction as to be liberated only 
when it passes into other combinations, and it may be this 
portion which is obtained in the action of metals on the gas ; 
the other portion, that essential to the acid, being sufficient to 
produce the requisite oxidation of the metal. i 
The question with regard to the existence of water in this 
state, Gay-Lussac and Thenard have already determined. From 
an extensive series of experiments, they found reason to conclude, 
that muriatic acid gas, in whatever mode it is prepared, is 
uniformly the same. From the quantity of hydrogen gas which 
combines with oxymuriatic gas in its formation, it follows that it 
contains 025 of water essential to its constitution. But the gas 
obtained by the usual processes, afforded, they found, exactly 
0°25 of water, when transmitted over oxide of lead, or combined 
with oxide of silver; and the same compounds are formed as by 
the action of oxymuriatic acid on silver and lead in their metallic 
state. They prepared muriatic acid gas, by heating fused 
muriate of silver with charcoal moderately calcined. 1t contained 
just the same quantity of water as muriatic acid obtained from 
humid materials, as it afforded the same quantity of hydrogen 
from the action of potassium. And instead of beimg capable of 
receiving the smallest additional portion of water, a single drop 
of water being imtroduced into three quarts of it, did not disap- 
pear, nor even diminish; but, on the contrary, increased in 
volume.* These facts establish the conclusion, that muriatic 
acid gas can receive no additional portion of water but that 
which is essential to it, and hence preclude the solution of the 
* Recherches Physico-chimiques, tom, ii, p. 133. 
