A SHIP ATTACKED BY A SWORD-FISH. 261 



lateral power, and might so ( wriggle its sword out of a 

 hole.' And so the insurance company will have to pay 

 nearly six hundred pounds because an ill-tempered fish 

 objected to be hooked, and took its revenge by 

 running full tilt against copper-sheathing and oak- 

 planking. 



(From the Daily News, December 11, 1868.) 



THE SAFETY-LAMP. 



As the late colliery explosions have attracted a 

 considerable amount of attention to the principle 

 of the safety-lamp, and questions have arisen re- 

 specting the extent of the immunity which the ac- 

 tion of this lamp secures to the miner, it may be 

 well for us briefly to point out the true qualities of 

 the lamp. 



In the Davy lamp a common oil-light is surrounded 

 by a cylinder of wire-gauze. When the air around 

 the lamp is pure the flame burns as usual, and the 

 only effect of the gauze is somewhat to diminish the 

 amount of light given out by the lamp. But so 

 soon as the air becomes loaded with the carburetted 

 hydrogen gas generated in the coal-strata, a change 

 takes place. The flame grows larger and less lumin- 

 ous. The reason of the change is this : The flame 

 is no longer fed by the oxygen of the air, but is 

 surrounded by an atmosphere which is partly in- 

 flammable; and the inflammable part of the gas, so 



