Owing to the absence of the generating materials in the mines of Cornwall, the hydrogenous gases of coal mines are entirely unknown. Accidents, however, occasionally, though very rarely, occur, from the accumulation of other of the irrespirable gases in long abandoned galleries; and it is very common in sinking deep shafts, or driving long galleries, to find the air so vitiated by respiration and combustion, and by the gases from exploded gunpowder, as to oblige the miner to fix his candle in almost a horizontal direction, to keep it from being extinguished. In cases of this kind artificial currents are, occasionally, produced by means of air pipes, &c.
In considering all the circumstances which can, in any way, affect the health of miners, we ought, perhaps, not altogether to overlook the fact of their subterranean labours being all performed in a very feeble light, a circumstance which forms a very striking contrast with the artificial glare of many of our manufactories, more particularly since the use of gas lights has become common.
Labours and habits of miners.─Setting aside the unwholesome nature of the occupation, I do not consider the labour of the miner as by any means severe; it is certainly much less severe than that of the stone-quarrier or mason. In respect, however, of injurious influence on the integrity of the animal frame, there are few kinds of bodily labour that can be compared with it. The subterranean labours of the miner commence at the early age of from eight to ten. At first, and for several years, the young miners are employed principally in conveying in wheelbarrows the ore and broken rock from the inner
