with Observations on its Chemical Constitution. 261, 
_ gas. -In the action of ignited metals cn muriate of ammonia, it 
is equally evident, on the same principle, that no water ought te 
be obtained. How, then, is the production of water to be ae- 
counted for? - 
Though the water obtained in these experiments cannot be de- 
rived from hygrometric vapour in the gas, there is another view 
under which it may be regarded as present, as an adventitious 
ingredient. The acid having a strong attraction to water, may 
be supposed, in the processes in which it is usually prepared, te 
retain a portion not strictly essential to its constitution as muri- 
atic acid gas, but still chemically combined,-—that is, combined 
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 requi- 
site oxidation of the metal. 
The question with regard to the existence of water in this 
state, Gay Lussae 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 uni- 
formly the sdme. From the quantity of hydrogen gas which 
combines with oxymuriatic gas in its formation, it follows, that 
it contains 0:25 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 me- 
tallic state. They prepared muriatic acid gas, by heating fused 
muriate of silver with charcoal moderately calcined. It con- 
tained just the same quantity of water as muriatie acid obtained 
from humid materials, as it afforded the same quantity of hydro- 
gen from the action of potassium. And instead of being eapa- 
ble of receiving the smallest additional portion of water, a single 
drop of water being introduced into three quarts of it, did not 
disappear, nor even diminish, but, on the contrary, increased in 
volume*. These facts eatnisiuls the conclusion, that muriatie 
acid gas can receive no additional portion of water, but that 
which is essential to it, and hence preclude the solution of the 
difficulty under consideration by the opposite assumption. And 
it is to be remarked, that should even such a portion of water 
exist in the gas, it cannot be supposed that the acid should carry 
this with it into its saline combinations, and retain it so, that it 
should not be expelled by heat. It cannot be supposed to exist, 
therefore, in muriate of ammonia thus heated, and of course can+ 
* Recherches Physico-chimiques, L. ii, p. 133. 
nat 
