40 ON THE FIRE-DAMP OF COAL-MINES, 



Iution, might, m situations peculiarly hazardous, be suspended 

 within the case, over the orifice of the air tube, which, if any 

 explosion were to happen, would, by the agitation, throw out 

 the fluid, and extinguish the flame. 



If, notwithstanding all these means of safety, there should 

 in any particular case be any dread of danger from the admis- 

 sion of inflammable air with the common air, this might 

 be completely obviated by an additional arrangement. The air 

 to supply the lamps might be brought by a cast-iron pipe from 

 any part of the mine where the danger did not exist, or, what 

 would give entire security, from the bottom of the shaft, where 

 the air must be pure. A pipe or pipes of this kind running 

 through the principal passages, small upright tubes might arise 

 from it at convenient distances to the fixed lamps. A similar 

 mode might be extended even to the moveable lamps ; the flex- 

 ible tube attached to the lamp might be of such a length as 

 to reach to a part of the mine where the air was known to be 

 pure ; or such flexible tubes might be adapted to branches fit- 

 ted with stop-cocks, and communicating with the main trunk. 

 Thus a system of perfect security, I conceive, would be attain- 

 ed. Independent of the other circumstances diminishing any 

 hazard, there are here only two modes of communication with 

 the external air, from neither of which can any danger arise, — 

 by the upper aperture, and the lower tube. The former can 

 admit no air to the lamp within, and the latter must convey 

 merely pure air. Both, therefore, must be perfectly safe. 



I have stated these diversities of method, merely to shew 

 how far the plan may be carried, where particular situations re- 

 quire it ; and absolute security attained : but it is very proba- 

 ble, that in general they will be unnecessary, and that the sim- 

 ple mode first explained, of a tube connected with the lamp, 

 supplying air from the floor, will be sufficient. 



This 



