1888.] on Safety Lamjps in Collieries. 211 



it gives, but tlie power it gives the viewer to examine the roofs of the 

 ways and workings ; it is so extremely portable and handy ; it can be 

 put anywhere ; the battery can be placed on the ground or suspended 

 by a spike to a tree, and the lamp can be fixed in the cap or around 

 the waist ; it can be put anywhere and used anyhow. 



Mr. Sopwith, at Cannock Chase, has been taking heavy batteries 

 to the working face, and using bright 5-candle lamps in reflectors, 

 so as to illuminate the working face with a light which in that 

 region is comparable to daylight. The men are charmed with it. 



The chief defects of the electric lamps are their fragility, the 

 liability of the carbon filament to break, the weight of the battery, 

 and the absence of gas detection ; and these defects have been very- 

 much enhanced by imperfect construction and injudicious details. 

 Electricians have not spent sufiicient time in the lower regions, and 

 practical colliers have no time to go to the laboratory. When the two 

 professions are properly amalgamated we shall very likely obtain the 

 true safety lamp. 



The electric lamp is not a fire-damp detector, but an electrical 

 appliance for this purpose is easily added. Liveing and Swan have 

 done this ; but it is doubtful whether a more efficient detector than the 

 Davy exists, and whether an apparatus that is so thoroughly under- 

 stood, and so thoroughly practical, will be superseded for a purpose 

 for which it seems so eminently adapted. 



I cannot conclude, especially in this place, with more pregnant 

 words than Davy's own : — " The grafification of the love of knowledge 

 is delightful to every refined mind; but a much higher motive is 

 offered in indulging in it when that knowledge is felt to bo practical 

 power, and when that power may be apj)lied to lessen the miseries or 

 increase the comforts of our fellow creatures." 



[W. H. P.] 



