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XIII, Erpsrimsjiis uith Sir H. Davy's Safe-Lamp. Bg 

 Dr. Ham^j,, of St. Pcierslurgh. 



OoME tiirsg ago I hnd nn onporttmitv of trvirg Sir Hum])hiy 

 Davy's l;imp in a coal-niine near Holywell in Fliiit.sliire. I de- 

 scended (alont; with Mcss.Willirim and Edward Roscoe) the pit 

 of Deebank colliery, 140 yards deep, and then proceeded hori- 

 zontally in one of the nietal-drilts, where in one place the in- 

 flan;mable gas was buhbling w ith considerable force through the 

 water, covering the bottom of the mine. The ventilation here 

 being so complete as to prevent any danger from e:<(.losion, I 

 kindled the gas with a connnon candle. It continued burning 

 with a flame about 1 1 foot long. Sir Humphry Davy's lamp 

 held in the sam.e current would not set fire to it. We now went 

 to a place near the end of the working, where in the roof of the 

 mine there is a considerable excavation constantly filled with 

 carburctted hydrogen, issuing from a fissure in the roof on that 

 spot. Holding the safety-lamp in the lower part of this exca- 

 vation, where the inflammable gas is always mixed with atmo- 

 spheric air, a succes'sion of slight explosions took place in the- 

 inside of the lamp ; but when raised into purer inflammable gas^ 

 the whole of the cylinder was filled with a faint blueish flame, 

 through which that of the wiek was distinctly visiible. On lifting 

 It still higher into the purest carburettcd hydrogen, the lamp 

 Eppeavcd extinguished, but rekii'.riied spontaneously when in- 

 stsntly withdrawn into atmospheric air. 



Having convinced myself that the lamp would not set fire to 

 the gas (and having been hreatiiing the same for some time, to 

 tiy its effects when taken into the lungs), we approached it with 

 a common candle tied to a long stick. The gas took fire with 

 considerable ej.pIosion, the lowermost stratum being mixed with 

 atmospheric air, and the remainder continued burning for some 

 time, filling three-fourths of the mine with an undulating blaze. 

 The ap])earance was awful, and gave me some notion of the maii- 

 uer in which those unfortunate persons perish, who meet witk 

 their death from accidents of this kind. 



Tiie lamp with which we made the experiment hfid a cylinder 

 of Ina-^s-wiTe gauze. It had become very hot during our trial* 

 with it, and I think the flame was greener than is common to 

 carhi'.retted hydrogeiv from coal-mines. I should suppose bras* 

 or copper wire would not stand so long as iron-wire gauze. 

 Mr. Buddie writes me " that he has had several lamps with /ro7z- 

 gauze cylinders for three months in daily use, without being in 

 the slightest degree impaired although they have been frequently 

 led hot for a considerable^ length of lime." The chief doubts 

 remaining In my mind with regard to the complete safety of the 



lamp. 



