.244 Dr. Henry's Additional Experiments 
It still, however, remains to be determined, what is the 
source of the hydrogene gas, which, in a limited proportion, 
is always evolved by the electrization of muriatic acid ? Does 
it result from the decomposition of water, existing as an ele- 
ment of the gas ; or from the disunion of the oxymuriatic acid 
and hydrogen, which, according to Sir H. Davy’s view, com- 
pose muriatic acid ? The limitation to its amount, which, it 
formerly appeared to me,* could only be accounted for by the 
complete destruction of the water contained in the gas, may 
now be equally well explained, on the principle which I have 
just pointed out. The fact, also, that no appreciable change 
of bulk is produced by the electrization of the muriatic acid, 
when the presence of mercury is excluded, is perhaps favour- 
able to the new theory. For since equal measures of hydro- 
gen and oxymuriatic acids afford muriatic acid without any 
condensation of volume, no alteration of bulk should result 
from the disunion of those elements ; and the products should 
be equal measures of the same gases. The proportions, which 
I obtained (100 to 140) did not, it must be acknowledged, 
exactly correspond with the theory ; but the difference was 
not greater, than might naturally be expected from the cir- 
cumstances of the experiment. That equal measures of hy- 
drogen and oxymuriatic acid are really evolved, appears to 
me to be proved by the agreement, which I have in several 
experiments remarked, between the hydrogen gas obtained, 
the same power, they ore again resolved into their elements* If this were the proper 
place, it might, I think, be rendered probable by several arguments, that electricity, 
when thus applied, acts rather by mechanical collision, than by inducing a change in 
the electrical states of the elements of bodies. 
* Phil. Trans, 1 800, p. 200. 
