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 



Vol. VIII P. II Q q acid 



