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longer safe; and though such a circum-stance can perhaps never happen in a col-liery, yet it ought to be known and guardedagainst.

I had an excellent opportunity, Septem-ber, 1816, of making experiments on a mostviolent blower, at a mine belonging to J. G.Lambton, Esq. This blower is walled offfrom the mine and carried to the surface,where it is discharged with great force. Itis made to pass through a leathern pipe, soas to give a stream, of which the force wasfelt at about two feet from the aperture in astrong current of air. The common singleworking lamps and double gauze lampswere brought upon this current, both in thefree atmosphere and in a confined air. Thegas fired in the lamps in various trials, butdid not heat them above dull redness, andwhen they were brought far into the streamthey were finally extinguished.

A brass pipe was now fixed upon theblower tube, so as to make the whole streampass through an aperture of less than halfan inch in diameter, which of course formeda most powerful blow-pipe, from which thefire-damp, when inflamed, issued with great