“AND PREVENTING ITS EXPLOSION. 33 
ed, may be the cause why it is more abundant in deep mines. 
Still, from whatever source it may be extricated, if the fact be 
correctly stated, that it has always an intermixture of carbonic 
acid, it is probable that it is in all cases derived from the de- 
composition of water by coal. (Note B.) 
It seems ‘to be altogether impracticable to prevent the pro- 
duction of this gas. To decompose or neutralise it in the mine 
by any chemical agency, as has been suggested, seems to be 
equally so. Only two resources apparently remain,—first to 
employ means of discharging it, so as to prevent any accumu- 
lation of it in large quantities ; and, secondly, to guard against 
its inflammation in working the mine, when from circumstan- 
‘ces occasionally unavoidable it does accumulate, until it can be 
discharged. 
The circumstance of explosions from the firing of this gas 
not occurring in many mines, situated even in districts where, 
from the nature of the coal, the depth of the workings, or 
other causes, such occurrences are frequent, seems to prove 
that there is no necessary accumulation of fire damp in 
the mine,—that the accumulation does not so much take 
place from unavoidable deficiency of ventilation, as from acci- 
dental obstructions to it in particular situations, or occasional 
eruptions of the gas from cavities in the coal or its accompany- 
ing strata, against which scarcely any.system can effectually 
guard,—that, therefore, the ventilation may be rendered effec- 
tive, and, by prudent and careful management, may be con- 
ducted so as to carry off the quantities evolved. In the Fell- 
ing Colliery, near Newcastle, in which the explosion that de- 
stroyed nearly a hundred persons, about three years ago, took 
place, the mine, it is stated, was considered as a model of per- 
fection in the purity of its air, from the system of ventilation ; 
and in an account of a second explosion in this mine, in which 
Vo. VIII. P. I. . E twenty- 
