48 ON THE FIRE-DAMP OP COAL-MINES, 



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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 



