WirS'ganze Safety ■ la wps for Miners. 57 



With the safe-lamp, liowever, it is reduced to the utmc3^ cer- 

 tainty, the actual piesenco and position of the gas is not only 

 ascertained with the greate?!t precision, but also every alteration 

 of circmnstance or position is distinctly perceived. 



By placing a lamp near the spot where a quantity of inflam- 

 mable air is i'isuing, and mixing with the circulating current of 

 atmospherical air to tlie firing point, it will be seen that very re- 

 mote causes frequently produce pulsations in the atrnospliere of 

 the mine, which occasion the gas to lire at nuked lights ; thus 

 showing clearly the instability of the element with which we havR 

 to deal, and the reason why so many explosions have occurred 

 where lights have not approached the place where the gas was 

 lodged within a considerable distance. 



Objections have been made by some who have not had expe- 

 rience of the lamps, to the delicacy of the wire-gauze, under the 

 apprehension that it may be very soon impaired by the flame 

 within the cylinder. Of this, however, I have no reason to com- 

 plain, as, after three months constant use, the gauze has not, in 

 the hands of careful workmen, been perceptibly injured by the 

 action of the flame ; but the outer top gauze of one or two of 

 Newman's making has been worn through by the friction of the 

 rivet* on the bottom of the swivel, to which the finger ring is 

 fastened ; but this only happened to the lamps itsrd by the waste- 

 men, whose business it is to travel daily in the various avenues of 

 the mines, for the purpose of keeping the passage for the current 

 of air tree from obstructions : nothing of the kind has happened 

 to the stationary lamps used by the colliers. In short, I do not 

 appreiiend tliat the gauze can be injured by any ordinary cause 

 without being observed in time sufficient to prevent accidents ; 

 and that we have no danger to ajjprehcnd, except from the gross 

 iiegligeuce of some heedless individual, or an accident of a very 

 unusual description occurring to injure the gauze. 



1 find that 1 have extended my letter to a greater length than 

 1 intended ; but I trust. Sir, that ypu will excuse nie for having 

 gone so much into detail, as I feel peculiar satisfaction in dwell- 

 ing upon a subject which is of the utmost importance not only to 

 the great cause of humanity, and to the mining interest of this 

 country, but also to the conmicrcial and manufacturing interests 

 of the Unrted Kingdom : for I feel convinced that by the happy 

 invention of the safe-lamp, large proportions of the coal mines of 

 the empire will be rendered available, which otherwise might 

 have remained inaccessible — at least without an invention of si- 

 milar utility, it could not have been wrought v.itlicut much loss 

 pfthe muicral, and risk of life and capital. 



* Tlu> rivet Is now fixcJ. H. D. 



It 



