THE SAFETY-LAMP. 263 



hastened by the flame playing against it, would cause 

 explosion ; ' and so on. It need hardly be said, how- 

 ever, that, imprudent as miners have often been, no 

 miner would remain where his lamp burned with the 

 enlarged flame indicative of the presence of fire- 

 damp. The lamp should also be at once extin- 

 guished. 



But here we touch on a danger which undoubtedly 

 exists, and so far as has yet been seen cannot be 

 guarded against by any amount of caution. Sup- 

 posing the miner sought to extinguish the lamp by 

 blowing it out, an explosion would almost certainly 

 ensue, since the flame can be forced mechanically 

 through the meshes, though it will not pass through 

 them when it is burning in the ordinary way. Now 

 of course no miner who had been properly instructed 

 in the use of the safety lamp would commit such a 

 mistake as this. But it happens, unfortunately, that 

 sometimes the fire-damp itself forces the flame of the 

 lamp through the meshes. The gas frequently issues 

 with great force from cavities in the coal (in which 

 it has been pent up), when the pick of the miner 

 breaks an opening for it. In these circumstances an 

 explosion is inevitable, if the issuing stream of gas 

 happen to be directed full upon the lamp. Fortu- 

 nately, however, this is a contingency which does not 

 often arise. It is one of those risks of coal-mining 

 which seem absolutely unavoidable by any amount of 

 care or caution. It would be well if it were only 

 such risks as these that the miner had to face. 



