*4,6 Dr. Henry’s Additional Experiments , c. 
either theory. According to the one which has been com- 
monly received, the oxygen unites with the real acid of mu- 
riatic gas, which becoming oxymuriatic acid, deposits water. 
On Sir H. Davy’s view, the oxygen unites with the hydrogen 
of the muriatic acid, and composes water, while the oxymuriatic 
acid is merely an educt. I am not aware of any refinement of 
the process, by which the value of these two explanations can 
be compared. Something, however, would be gained by a pre- 
cise determination of the proportions, in which the two gases 
saturate each other. For since, on Sir H. Davy’s theory, mu- 
riatic acid contains half its volume of hydrogen gas, two mea- 
sures of which are known to be saturated by one of oxygen, 
it follows that muriatic acid gas should be changed into oxy- 
muriatic by one-fourth of its bulk of oxygen. According to 
Gay Lussac and Thenard,* three measures of muriatic acid 
should condense one of oxygen (or only one-third their bulk), 
and should form two measures of oxymuriatic acid. Hitherto, 
I have not been able to satisfy myself respecting the true pro- 
portions of oxygen and muriatic acid gases, that are capable 
of being united by electricity; for though I have made several 
experiments with this view, they have not agreed in yielding 
similar results. The condensation of a part of the undecom- 
posed acid by the water, which is formed during the process, 
will, probably, indeed, always be an impediment to our learn- 
ing these proportions exactly. The fact is chiefly of value, 
as it affords an example of the production of oxymuriatic acid 
under the simplest possible circumstances ; and as it shews 
unequivocally that, under such circumstances, the visible ap- 
pearance of moisture is a part of the phenomena. 
* Memoires d’Arcueil, ii. 217. 
Manchester* Jan, 6, 1812. 
