' ON MURIATIC ACID GaAs, &c. 303 
But though TI consider this conclusion as established, there 
-is a considerable difficulty attending the theory of the experi- 
ment. The result of water being obtained is actually different 
from what is to be looked for, on the doctrine of muriatic acid 
gas containing combined water ; and even when the fact is 
established, the theory of it is not easily assigned. On that 
doctrine, it must be held that in the action of metals:on muriatic 
acid gas, the metal ‘attracts oxygen from: the water, the corre> 
sponding hydrogen is evolved, and the oxide formed combines 
with the- real acid. No water, therefore, ought to be deposi- 
ted, for none is abstracted from the acid, but what is spent in: 
the oxidation of the metal: This will be apparent, by attend- 
ing to the proportions in a single example, from: the scale of 
chemical equivalents: 100 grains of iron combine:with 29 of 
oxygen, and in this state of oxidation unite with. 99 of real mu- 
riatic acid. This quantity of acid exists in 131.8 of muriatic 
acid gas, combined with 32.8 of water ; and this portion of wa- 
ter contains 29 of oxygen with 3.8 of hydrogen... There is pre- 
sent, therefore, exactly the quantity of oxygen.which. the me- 
tal requires to combine with the acid; and no. water remains 
above this: Or it may be idleagnated: under another point of 
view. Muriatic acid gas is composed of oxymuriatic gas and 
hydrogen. A: metal acting on it must attract the oxymuriatic 
-acid,—that is, the muriatie acid-and oxygen, and liberate the 
hydrogen. No water, therefore, aught 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 ob- 
tained. . How, then, is the production of water to be account- 
ed for ? 
~-Though the water obtained in. these experiments cannot be 
derived from hygrometric vapour in the gas, there.is another 
view 
