110 On Coal-Mines. [Aue.: 
That letter contained an account of the methods most generally 
pursued of ventilating coal-mines, accompanied with draughts illus- 
trative of the different descriptions. From these one may form a 
very accurate notion of the principle upon which the ventilation 
proceeds, and that it of course depends upon a thorough circulation 
of atmospheric air being kept up through all the different coursings 
and workings of the mine. So rapid, however, is the’ ordinary 
accumulation, and sometimes so unexpected is the accession of in- 
flammable gas, that with all the apparatus of ventilation in the most 
complete condition, it is a matter of no small difficulty to keep the 
air in circulation in a state fit for the various purposes, or in the 
language of miners, to prevent it from reaching the firing point, or 
point of hydrogenous impregnation at which it explodes when 
brought in contact with the flame of a candle. The slightest inter- 
ruption to the regular transmission of atmospheric air, or the least 
unlooked-for addition of carbureted hydrogen, exposes the lives of 
the miners to the most imminent jeopardy, and the mine itself to 
the risk of total destruction. It would appear that as far as mecha- 
nical means are adequate to the end, ventilation has reached the 
utmost point of perfection of which it is susceptible. Mr. Buddle 
in some measure stakes his reputation as a viewer on the opinion, 
that any further advancement in the discovery of mechanical powers . 
for the ventilation of collieries is unattainable. His words are: 
“© On the strength of my own experience in collieries thus circum- 
stanced, I freely hazard my opinion, that any further application of 
mechanical agency towards preventing explosions in coal-mines 
would be ineffectual ; and therefore conclude that the hopes of this 
Society ever seeing its most desirable object accomplished must 
rest upon the event of some method being discovered of producing 
such a chemical change upon carbureted hydrogen gas as to render 
it innoxious as fast as it is discharged, or as it approaches the neigh- 
bourhood of lights. In this view of the subject, it is to scientific 
men only that we must look up for assistance in providing a cheap 
and effectual remedy.” (Report, p. 23.) These positions, though 
perhaps not very accordant to the genuine spirit of philosophy, as 
tending rather to repress than to animate the zeal of discoverers, 
may in the present case be assumed as principles for the purpose of 
simplifying and facilitating the discussion. By the publication, 
therefore, of Mr. Buddle’s letter in the Report alluded to, our 
knowledge of this part of the subject may, in one respect, be con- 
sidered as having not only advanced a step, but our perceptions of 
what we do know, and of what remains to be done, are rendered 
more clear and precise. According to this view, then, we may be 
said to have arrived at a fixed point. We have reached, as it were,: 
a spot from which we can see more distinctly the route to be pur- 
sued. A person, in every respect qualified to pronounce.a deliberate 
and decided opinion, has declared ihat all further attempts at im-. 
provement in what may be called the mechanism of ventilation will. 
prove abortive, and that it is to scientific men that we are to trust- 
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