48 ON THE FIRE-DAMP OF COAL-MINES, 
NOTES. 
Note A. page 2.—The production of fire-damp is much less 
considerable in the Scotch collieries than in those of the west, 
or the north of England. It would be important to discover 
the cause of this, but it is not very obvious. Probably it arises 
from the smaller scale on which they are wrought. In some 
of them, however, it does occur, though in quantities not so 
considerable, but that it is usually carried off by the common 
mode of ventillation, or by firing it as it begins to accumulate. 
In the mines in Ayrshire, it is the practice to fire it daily. 
Within these few years, explosions from it have in different 
cases been productive of fatal accidents, some of them, espe- 
cially in the mines in West Lothian and Stirlingshire, to a 
considerable ‘extent. ; 
Note B. page 4—No question can be more important in re- 
lation to the subject of the fire-damp of mines, than that with 
regard to the causes of its production. The facts stated in the 
text prove, that it is not entirely from the old wastes that the 
gas is discharged, though they may afford a large quantity of 
it. Its evolution might be considered as a circumstance in part 
connected with the original formation ; the gas might be sup- 
posed to have been formed with the coal, to be confined by 
pressure in its mass, or its interstices, and to be liberated as 
the pressure is removed by the working. The density of the 
mass of coal, however, can scarcely be supposed to be such, as 
to have confined the gas from its first consolidation, and it 
must 
