46 ON THE FIRE-DAMP OF COAL-MINES, 
It is farther obvious, that the mode of producing illumina- 
tion by coal gas may be connected with this method, at least 
so far as regards the fixed lamps. The gas might be prepared 
by a furnace, at a part of the mine where there would be least 
hazard from carrying on the operation,—at the bottom of the 
air-shaft, for example, where a strong current of air moves out- 
wards, and the gas might be conveyed through a main trunk, 
to pipes terminating by a small aperture within the glass-case. 
Its combustion, as it issued from the aperture, might be sus- 
tained with safety by the current of common ‘air, supplied in 
the mode already described. A very brilliant illumination 
might thus be obtained; and from the peculiar advantages of 
situation, this might be done so economically, that it might 
render moveable lamps, to which the method could not well 
be applied, unnecessary. It might even become a source of 
advantage, by getting rid of much of the waste coal, and con- 
verting it into coak. It is possible, however, that the attention 
required in the process, and its interfering with the operations 
of the mine, might, independent even of any supposition of ha- 
zard, render the propriety of its introduction doubtful. 
‘Tne general method, I may add, will prove equally effectual — 
in obviating the danger from Choak-damp, carbonic acid gas, 
the other evil which miners dread, and which often also occurs 
in caverns, subterranean passages, and other situations. From 
its specific gravity being so much greater than that of atmo- 
spheric air, it is known to remain nearly at the floor, and to ex- 
tend very gradually upwards. A person, therefore, may ad- 
vance with safety, where it is present, by the precaution of 
holding 
