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this coal, when the pressure of the super-incumbent material is removed, affords in-flammable air; which is disengaged notonly in the common operations of mining,when the coal is broken and removed, butis likewise permanently evolved, often inenormous quantities,* from fissures in thestrata.

When it has accumulated in any part ofthe gallery or chamber of a mine, so as tobe mixed in certain proportions with com-mon air, the presence of a lighted candleor lamp causes it to explode, and to destroy,injure, or burn whatever is exposed to itsviolence.

To give detailed accounts of the tremen-dous accidents, owing to this cause, wouldbe merely to multiply pictures of death andof human misery.—The phenomena are al-ways of the same kind.—The miners areeither immediately destroyed by the explo-sion, and thrown with the horses and ma-chinery through the shaft into the air, themine becoming as it were an enormous

* This phenomenon is called, in the language of theNorth country miners, a blower.

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