108 _ Experiments on Muriatic Acid Gas, 
niacal and muriatic acid gases. Miuriatic acid gas being the 
sole product of the mutual action of oxymuriatie gas and hydro- 
gen, it follows, that if oxymuriatic gas contain oxygen, muriatie 
acid gas must contain combined water ; while, if the former be 
a simple body, the latter must be the real acid, free from water. 
When muriatic acid gas is submitted to the action of substances 
which combine with acids, water is obtained; but though the 
most simple and direct conclusion from this is, that the water is 
deposited irom the muriatic acid gas, the result may be accounted 
for, on the opposite doctrine, by the supposition that it is water 
formed by the combination of the hydrogen of the acid with the 
oxygen of the base. Ammonia, however, containing no oxygen, 
if water is obtained from its combination with muriatiec acid gas, 
we obtain a result which cannot be accounted for on this hypo- 
thesis, but must be regarded as a proof of the presence of water 
in the acid gas. And this, again, affords a proof equally con- 
clusive of the existence of oxygen in oxymuriatic gas. 
The results of the experiment which I had brought forward 
were involved in much controversial discussion: and a brief re- 
capitulation of the objections that were urged to it is necessary, 
as an introduction to the experiments I have now to submit, and 
to the consideration of the present state of the question. 
The original experiment was performed by combining thirty 
cubic inches of muriatic acid gas with the same volume of am- 
moniacal gas carefully dried. The salt formed was exposed in a 
small retort with a receiver adapted to it, to a moderate heat 
gradually raised. Moisture speedily condensed in the neck of 
the retort, which increased and collected into small globules*, 
This result was admitted by those who defended the new doc- 
trine, when the experiment was performed in the manner I have 
described,—water being obtained, it was allowed, ‘‘ in no incon- 
siderable quantity.’ But, to obviate the conclusion, it was as- 
serted, that this is water which has been absorbed by the salt 
from the atmosphere. ‘This was affirmed by Sir Humphry Davy, 
who stated that the salt absorbs water in this manner to a very 
considerable extent ; that it is only from the salt in this state 
that water can be procured; and that when it is formed from the 
combination of the gases in a close vessel, and heated without 
exposure to the air, not the slightest trace of water appears, 
even when the experiment is performed on a large scale. 
The reverse of this I was able to demonstrate by further ex- 
perimental investigations. It was shown, that the salt absorbs 
no moisture from the air in the common state of dryness and 
* Nicholson's Journal, vol. xxxi. p. 126. y: 
temperature 
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