-AND PREVENTING ITS EXPLOSION. 39" 
sion. Thus coming barely within the verge of the power of 
exploding, and owing it to. these circumstances of quantity and: 
condensation, there is every probability, that if kindled in small 
quantities it would not explode, and that, presented: to an igni- 
ted body much diluted and in a rarefied state, it would not 
even inflame. Hence the chance of its inflaming in a lamp 
such as that described, is inconsiderable, were it even admitted. 
to the flame; and the certainty of its not exploding might al- 
most be depended on. The security from this might even be 
carried so far, by adapting properly the size of the upper aper- 
ture, so as to produce the greatest degree of rarefaction in the- 
air, that if a mixture of the fire-damp with atmospheric air 
were introduced, it might, instead of inflaming, become inca- 
pable of supporting the combustion, or at least might so far 
weaken the flame, as to give indication of the danger. 
Lastly, If even, from some singular cause, an explosion did 
bappen within the case-of the lamp, it appears to me very 
doubtful if it would. be propagated farther. It must be ex- 
tremely feeble. The flame or ignition could not be communi- 
cated by the upper aperture to. the air without, partly from its 
smallness, and partly from the upper part of. the lamp being 
previously occupied by air not capable of kindling. Nor could 
it be easily. communicated downwards through the tube, espe- 
cially in a flexible tube, the sides of which would first yield, 
and then collapse ; and though conveyed downwards, there 
would be little or no probability of an air occupying the floor 
of the- mine capable of being inflamed. The risk of such a 
communication, if it were thought there-were any, might pro-.. 
pably also be diminished by conveying the air rather by seve- 
ral small tubes. than by one larger. Other contrivances suffi- 
eiently simple, if they were supposed necessary, might be em- 
ployed, A cup containing water, for example, or a saline so- 
lution, 
