208 THE FIRE-DAMP'S FAMILY CIRCLE. 



succeeded in giving effect to my convictions, the point need 

 not be insisted on again, that whatever in the way of safety- 

 lamps has come out of wire gauze, or is able to come out of 

 the same, should stand to the credit of Davy. By taking this 

 broad view of the matter, the question, whether the original 

 lamp, or a modification of the same, be the better, is freed from 

 the disturbing element of predilection in favour of or against 

 the inventor. After examining the parliamentary evidence 

 given on different occasions respecting safety-lamps, the con- 

 clusion, I think, will be arrived at, that a balance of testi- 

 mony is in favour of the position that Davy's original lamp 

 is more completely adapted to the miner's wants than any 

 variety of it. 



At any rate this much is clear, many qualities in addition 

 of that of safety must be embodied in a. safety-lamp. Were 

 the latter alone to be considered, the lamp of Humboldt in 

 which connection with the external atmosphere is totally cut 

 off leaves nothing to be desired. The water-valve lamp of 

 Clanny is perhaps quite as safe ; but the weight, the complexity 

 of it, and the limitation of combustive power in the former, 

 are circumstances which expunge them from the list of prac- 

 tical safety-lamps. Amongst wire-gauze lamps, again, I be- 

 lieve that devised by Koberts to be safest of all ; but a fatal 

 objection to it is, as remarked, that whenever the atmosphere 

 becomes a little impure, it ceases to be a lamp it goes out, 

 leaving the miner to find his way back through the dark laby- 

 rinth of galleries the best way he can. 



Amongst the expedients which have been proposed of late 

 for illuminating coal-mines, that of substituting gas for oil- 

 wicks in safety-lamps is suggestive of good promise. At the 

 best of times the safety-lamp gives little light; when the wick 

 becomes foul from long burning when, in other words, it re- 

 quires trimming the light is necessarily diminished. Now, 

 although there are contrivances for effecting this trimming 

 without removing the cage, yet for the most part so inefficient 



