THE SAFETY LAMP. 137 



hydrogen. It also contained a little carbonic 

 acid and nitrogen. It burns with a pale bluish 

 white flame, emitting considerable light and 

 heat. As it issues from the pipe it has a moist 

 or slightly musty smell, as of sticks partially 

 decomposed ; but, after it has been kept a little 

 time, it becomes quite inodorous. It does not 

 appear that the employment of it entails any 

 evil consequences to the health of the family." 

 When it escapes into mines, it forms the awful 

 and dangerous gas too well known as " fire- 

 damp." This gas becomes explosive only when 

 mixed with a certain quantity of air ; if then 

 a flame is applied to the mixture, it explodes 

 with all the violence of gunpowder, and with 

 great noise. Still more recently the inflam- 

 mable gas rising from a bog has been made 

 to drive a steam-engine, by being carried under 

 the boiler. 



In consequence of the awful accidents which 

 have occurred, owing to the escape of this gas 

 into coal mines, and to its subsequent explosion 

 by coming in contact with the lighted candle of 

 the miner, Sir H. Davy undertook the task of 

 endeavouring to discover some remedy for these 

 calamities. His labours were ultimately re- 

 warded by the discovery of the invaluable safety 

 lamp, with which his name will be connected 

 through all time. It may be interesting to 



