194

COAL HINES OF

air and one of fire-damp, but had the effectupon six of air and one of fire-damp; butvery strong sparks from the discharge of aLeyden jar possess the power of exploding thegas in the same manner as a lighted taper:burnt charcoal to any degree of heat did notexplode mixtures of air and fire-damp. Ironheated red hot, and to a common degree ofwhite heat, did not explode it, but when inbrilliant combustion produced the effect.

Numerous other experiments were performedby this able philosopher, of more importanceto the chemist than to the miner, except in theresults which may be anticipated from scien-tific men becoming acquainted with new factsrelevant to this matter. Metallic tubes of one-fifth of an inch in diameter, and one inch anda half long, were found safe canals for convey-ing the fire-damp; but the most extraordinaryand important discovery was the security ofgauze wire, which proves impervious to flame,and, though surrounded by inflammable air,prevents any inflammation within from com-municating to it.

Azote and carbonic acid were found to dimi-nish the explosive power of the fire-damp, andOne of carbonic acid to seven of an explosive.mixture prevented an explosion. These facts