92 Mr. Davy’s Lecture on some new analytical Researches 
proper proportions, they both entirely disappear ; a white salt 
is formed, and a quantity of pure hydrogene gas evolved, 
which equals about one third of the original volume of the 
gas. 
By eight grains of potassium employed in this way, I ef- 
fected the absorption of nearly twenty two cubical inches of 
muriatic acid gas ; and the quantity of hydrogene gas produced 
was equal to more than eight cubical inches. 
The correspondence between the quantity of hydrogene 
generated in cases of this kind, and by the action of potassium 
upon water, combined with the effects of ignited charcoal 
upon muriatic acid gas, by which a quantity of inflammable 
gas is produced equal to more than one third of its volume; 
seemed to shew, that the phenomena merely depended upon 
moisture combined with the muriatic acid gas.* 
To determine this point with more certainty however, and 
to ascertain whether or no the appearance of the hydrogene 
was wholly unconnected with the decomposition of the acid, I 
made two comparative experiments on the quantity of muriate 
of silver, furnished by two equal quantities of muriatic acid, one 
of which had been converted into muriate of potash by the ac- 
tion of potassium, and the other of which had been absorbed 
by water ; every care was taken to avoid sources of error ; 
and it was found that there was no notable difference in the 
weight of the results. 
• When the Voltaic spark is taken continuously, by means of points of charcoaf 
in muriatic acid gas over mercury, muriate of mercury is rapidly formed, a volume 
of inflammable gas, equal to one third of the original volume of the muriatic acid, 
gas appears. The acid gas enters into combination with the oxide of mercury, so 
that water enough is present in the experiment to form oxide sufficient to absorb the 
whole of the acid. 
