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the feeder or safe chimney as well as drawncylinders of brass.

A candle will barn in a lantern or glasstube made safe with metallic gauze, as wellas in the open air; I conceive, however,that oil lamps, in which the wick will al-ways stand at the same height, will be pre-ferred.

But the principle applies to every kindof light, and its entire safety is demon-strated.

When the fire-damp is so mixed withthe external atmosphere as to render it ex-plosive, the light in the safe lantern orlamp Avill be extinguished, and warningwill be given to the miners to withdrawfrom, and to ventilate that part of the mine.

It is probable, that when explosions occurfrom the sparks from the steel mill, themixture of the fire-damp is in the propor-tion required to consume all the oxygeneof the air, for it is only in ajbout this pro-portion that explosive mixtures can befired by electrical sparks from a commonmachine,.

As the wick mgy be moved without com-munication between the air in the safe lan-