402 Mr. Henry's Experiments on 
evidence thus produced in favour of the composition of char- 
coal ; and amongst these it may be sufficient to mention Dr. 
Beddoes, who has availed himself of the theory of Dr. Austin, 
in explaining some appearances that attend the conversion of 
cast into malleable iron.* 
The heavy inflammable air, having been proved to consist 
of a solution of pure charcoal in light inflammable air, is termed, 
in the new nomenclature, carbonated hydrogenous gas. By 
repeatedly passing the electric shock through a small quantity 
of this gas, confined in a bent tube over mercury. Dr. Austin 
found that it was permanently dilated to more than twice its 
original volume. An expansion so remarkable could not, as he 
observes, be occasioned by any other known cause than the 
evolution of light inflammable air. 
When the electrified air was fired with oxygenous gas, it 
was found that more oxygen was required for its saturation 
than before the action of the electric fluid ; which proves that, 
by this process, an actual addition was made of combustible 
matter. 
The light inflammable air disengaged by the electrization, 
proceeded, without doubt, from the decomposition of some sub- 
stance within the influence of the electric fluid, and not merely 
from the expansion of that contained in the carbonated hydro- 
genous gas: for had the quantity of hydrogen remained unal- 
tered, and its state of dilatation only been changed, there would 
not, after electrization, have been any increased consumption 
of oxygen. 
The only substances in contact with the glass tube and mer- 
cury, in these experiments, besides the hydrogen of the dense 
* Phil. Trans. Vol. LXXXI. 
