exqrs 
ON MURIATIC ACID GAs, &c. 301 
' In all the preceding experiments, water has been procured 
from muriatic acid gas. It is obvious, that such a result can- 
not be accounted for on the hypothesis, that-it is the real.acid 
free from water, a compound merely of chlorine and hydrogen. 
On the opposite doctrine, as muriatic acid in its gaseous: form. 
is held to contain water, it may be supposed. to aa a portion 
of it. 
siltk may be cata however, in this, as it was in the ex- 
periment of obtaining water from the muriate of ammonia by 
heat, that the water produced is derived from hygrometric va- 
pour in the gas. To obviate this, it is sufficient to recur to 
the fact established by the experiments of Henry and Gay 
Lussac, that muriatic acid gas contains no hygrometric vapour ; 
and to the obvious result in the experiment, that no quantity 
that can be assumed, would be adequate to account for the 
quantity. ramen nibtaihied: The circumstances of the experi- 
_ Ment, 
monia, and that this might afford an easy mode of exhibiting the results. I ac- 
cordingly found, that on mixing different metals with sal ammoniac in powdery, 
- previously exposed to a subliming heat, and exposing the mixture to’ heat by a 
lamp, so regulated as to be short of volatilization, the salt was decomposed, am- 
moniacal gas was expelled, and moisture condensed in the neck of the retort ; 
covering @ space of several inches with small, globules, and at length running 
down. . The metals I employed were iron, zine, tin, and lead; 100, 150, or 200 
grains of each metal, dry and warm, being mixed with 100 grains of the salt,, 
likewise newly heated. To obviate any fallacy from common sal ammoniac be- 
ing employed, I repeated the experiment with the salt formed from the combina- 
tion of its two constituent gases, and obtained the same result. But although 
this affords an easy mode of exhibiting the production of water, it is not favour- 
able to obtaining a perfect result, the heated ammoniacal gas carrying. off a :con- 
siderable post of the water deposited ; and accordingly, the quantity, instead. 
of increasing as the experiment proceeds, at length diminishes, and the ammoni- 
acal gas deposites a portion of water in passing through mercury, or in being con- 
veyed through a cold tube. 
