of charcoal and hydrogen. 149 
completely shaded by an opake cover which was fitted over it. 
The oil or coal gas was then added by degrees, if much con- 
densation was expected, because in that case a considerable in- 
crease of temperature would have been produced by the sudden 
admixture of large quantities ; or at once, if onty a moderate 
action had been indicated by the previous assay. The mixture 
was allowed to stand, completely guarded from the light, 
during 30 or 40 minutes, or even longer, and the residue was 
expeditiously washed with liquid potash, and a small portion 
again assayed, to ascertain that the action of the chlorine was 
complete. The specific gravity of the washed gas was then 
carefully taken, that of the entire gas having been previously 
determined : and the results of its combustion with oxygen 
examined, and compared with those of the gas in its original 
state. 
Experiments on the gas from oil. 
In obtaining this gas at different times, I used the same 
kind of whale oil, which had been heated a little below its 
boiling point during two hours, in order to deprive it of water. 
The oil was admitted by drops into an ignited iron tube filled 
with fragments of broken crucibles, and no difference, that I 
am aware of, existed in the circumstances under which the 
decomposition was effected, except that the degree of heat 
was purposely lowered in the latter processes, till that tem- 
perature was attained, which was barely adequate to the pro- 
duction of gas. The oil gas procured from London, I obtained 
through the kindness of Mr. Richard Phillips. It had been 
prepared from cod oil, at the manufactory of Messrs. John 
and Philip Taylor, and having been conveyed to Manches- 
ter in bottles accurately stoppered and tied over with a double 
