176

COAL MINES OF

would not suit; for the expansive force of theexplosions within the lamp threw open thevalves and allowed a communication to takeplace between the candle and the surrounding’atmosphere; besides, the water when used asa valve not only keeps the apparatus cool, butensures perfect safety. I was told that fre-quently large masses of coal are struck off fromthe sides of the mine whilst the pitmen arehewing out the coal, as I have witnessed myself;and should a piece of coal strike the lamp uponthe side, it would of course break it, and exposethe inflammable gas to an instantaneous ex-plosion.”*

Dr. Clanny then goes on to describe theuses and application of his invention, whichit will not be necessary to repeat here, as theyare mentioned in a former part,'f- and con-cludes thus: “ I made many fruitless efforts

* I have heard similar remarks to these from practicalmen; but they are founded upon such extreme cases asentitle them to be noticed more as the objections of preju-dice than actual ones : it is true, these circumstances oftenoccur, but seldom in such a manner as to affect Dr.Clanny’s lamp. With Sir H. Davy’s however, or Dr.Murray’s, I could not say the same, as their constructionis unavoidably too light to withstand a common splinterof stone or coal.

f See ,p. 107—114,