THE SAFETY-LAMP. 261 



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 

 extinguished. 



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. Supposing 

 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. Fortunately, however, this is a con- 

 tingency 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. 



