457 
of carbon and hydrogen^ 
that I have frequently observed a substance come over in 
small quantity, rising with the vapour which boils off at 50® 
or 60®, and crystallizing in spiculae in the receiver at 0°. A 
temperature of 8® or 10° causes its fusion and disappearance. 
It is doubtless a peculiar and definite body, but the quantity 
is extremely small, or else it is very soluble in the accompa- 
nying fluids. I have not yet been able to separate it, or 
examine it minutely. 
I ventured some time since upon the condensation of vari- 
ous gases,* to suggest the possibility of forming a vapour 
lamp, which containing a brilliantly combustible substance, 
liquid at a pressure of two, three, or four atmospheres at 
common temperatures, but a vapour at less pressure, should 
furnish a constant light for a length of time, without requiring 
high, or involving inconstant, pressure. Such a lamp I have 
now formed, feeding it with the substance just described ; 
and though at present it is only a matter of curiosity, and 
perhaps may continue so, yet there is a possibility that pro- 
cesses may be devised, by which the substance may be formed 
in larger quantity, and render an application of this kind 
practically useful. 
On the remaining portions of the condensed oil gas liquor. 
It has been before mentioned, that by repeated distillations 
various products were obtained, boiling within limits of tem- 
perature which did not vary much ; and which when distilled 
were not resolved into other portions, differing far from each 
other in volatility, as always happened in the earlier distilla- 
tions. Though conscious that there were mixtures, perhaps 
* Quarterly Journal of Science, XVI. 240. 
