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we have yet by any means attained to a system of perfection. 
The almost constantly-recurring explosions in mines fearfully 
remind us there remains yet much to be done before the 
desideratum in this respect is accomplished. But what is 
it that makes the difficulties so great in the way of achieving 
what is admitted by many, and lamented by all, as being 
essentially necessary to prevent explosions in mines ? Diver- 
sity of opinion, prejudice, and (I wish it to be understood 
when I use the term, I mean it is not intentional) ignorance 
combined, have formed, hitherto, an almost insurmountable 
barrier. It will be necessary to inquire, first, to what are 
all the dreadful events that have been so destructive to life 
and property in mines to be attributed ? 
As to the direct cause of an explosion of carburetted 
hydrogen gas in any mine, there cannot be two opinions, 
simply because the gas does exist, and a light being intro- 
duced into the explosive mixture it must necessarily ignite. 
But as to the secondary or producing cause, opinions are 
wide as the poles. Perhaps the following are the principal 
causes : first, sudden and extensive eruptions of gas from the 
roof or floor, or from the coal ; second, accumulated gas 
in goaves or old workings ; third, gradually liberated gas 
in the actual workings of the mine. Eruptions of gas in a 
sufficient quantity to cause an explosion are of rare occur- 
rence, and are almost exclusively confined to deep mines, 
simply because there is no natural or artificial communica- 
tion with the atmosphere or surface of the ground. In mining 
operations cavities are found to exist in which such gas is con- 
fined until liberated by underground workings or sinkings. In 
case of an eruption to any extent, an explosion is almost 
certain, without the greatest care and a powerful current of 
pure air to dilute the gas emitted. To accumulated gas in 
goaves or abandoned workings, (I use the expression 
advisedly) most explosions have in the past been attributed. 
