36 ON THE FIRE-DAMP OF COAL-MINES, 
have now to explain, will be found, I trust, possessed of these 
advantages. 
The facts on which it is in a great measure founded, are, 
that the inflammable gas accumulates in the roof of the mine, 
—that it is fired, in the usual mode of lighting, before the mix-- 
ture of it with the atmospheric air fills the-mine, or that part» 
of it in which the accumulation is taking place,—and that it: 
cannot fill it while the mine-is worked; as the respiration of the: 
workmen would be: previously affected. The miner works: 
with his candle or lamp-at a certain elevation, occasionally mo-. 
ving with it; and thus when the fire-damp has accumulated so: 
far as to fill a considerable part of the roof, the accidental ap-. 
proach of the lamp, or some concussion throwing the gas: 
downwards, so as to bring it into contact with the flame, sets: 
it on.fire. In one of the explosions, for example, within these 
two years, that of the Hall Pit near Sunderland, in. which thir-: 
ty-two men were killed, the explosion was supposed to have. 
been occasioned by the fall of a stone from the roof, which car-- 
vied the inflammable air with it, so as to bring it into contact: 
with the pitmens’ candles; and this circumstance of a flake or 
mass falling from the roof, and throwing the inflammable air: 
before it to the candles, has been often assigned as-a cause of. 
these explosions. It isa proof of what is indeed sufficiently 
established, the accumulation of the inflammable gas in the: 
roof of the mine. . 
The method, therefore, which I would propose is, to bring 
the supply of air to sustain the combustion of the lamp from: 
the floor of the mine. This may be easily done by burning: 
the lamp within a glass-case, having a small aperture at the 
top to. admit of the escape of the heated air and smoke, and» 
having attached to the under part of it a tube reaching to the 
floor of the mine to convey the-air. Figure Ist, Plate I. re- 
presents this in a fixed lamp. 
One 
