a 
-ON MURIATIC AcID Gas, &c. 305 
facts establish the conclusion, that. muriatic acid gas can re- 
-ceive 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 re- 
marked, 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, there- 
fore, in muriate of ammonia thus heated, and of course cannot 
account for the water obtained. by. the action of the metals on 
this salt.. 
When it is proved, that no extrinsic water exists in muriatic 
acid gas, there remain apparently only two modes on which the 
production of water can be explained,—either, that the metal 
may require less-oxygen’ than is supposed:in combining with 
the acid, so. that. a portion of water will remain undecomposed, 
to be deposited:: or, that the oxide attracts more real acid, so 
as to liberate a larger proportion of water.. The-first of these 
suppositions is improbable, from the consideration of the law 
which regulates:the combination of metallic oxides with acids, 
—that the quantity of acid is proportional to the quantity. of 
oxygen,. so that if an oxide were formed. in these cases, at-a 
lower degree of oxidation, it would only combine with a pro- 
portionally smaller quantity of acid, and the quantity of. water. . 
detached from the combination: would be the same. 
No improbability is attached to the second ‘supposition ; and 
it has even some support from the consideration, that many 
metallic saline compounds, form with. an: excess:of acid; and 
that: it is difficult, with regard to a number of them, to procure 
them neutral. Metallic muriates, with excess:of acid, seem in 
particular to be established with facility. And although an ex- 
cess of metal be present in the action exerted on. muriatic 
Vor. VIE. P. I Qq acid 
