DURHAM AND NORTHUMBERLAND, 189

lieries. A few days following, a paragraph ap-peared in the Durham paper announcing thatStephenson’s lamp had been used six weeks inthe Killingworth Main pit: this, however, is notof much consequence, further than what relatesto the testimony of its application. The leastprevalence of carburetted hydrogen, or carbonicacid, extinguishes the light; and it is so ex-tremely feeble that I doubt very much whetherthe many concussions to which it would beexposed would not perpetually leave theworkmen in darkness.

It has been stated * that no explosion tookplace when carburetted hydrogen gas was sentinto the lamp. This is very true ; but the gaswas only sent in in inflammable quantities, andnot in exploding proportions: this caused thelight to expand and then go out, and though Isuggested the experiment of inverting a smallgasometer over the chimney of the lanternI did not see it satisfactorily fulfilled ; for thegas being sent in so as only to cause an in-flammation did not produce those effects whichprobably would have resulted had the air beenproperly mixed up to the firing point. I cer-tainly did not see the candle put into the

* See Tilloch’s Phil. Mag. 1816, p. 459.