from "Fire-damp in Mines. It 



considerable size,) and the ash-pit is purposely constructed, 

 by being closed in front, and provided with a door, through 

 which the ashes may be removed, all the air required for 

 combustion must necessarily be forced up the pipes out of 

 the shaft, owing to the great rarefaction existing in the 

 ash-pit and engine chimney. The fire bars should in this 

 case be far asunder, and be kept very clean, in order to 

 allow a greater quantity of air to pass through their inter* 

 stices. 



Another plan consists in the use of Hast cylinders, 

 worked by the engine. Though these are generally con- 

 structed so as to force air down the pipes, yet I should re- 

 commend the reverse mode, because it will frequently oc- 

 cur that the air will be foul in some parts of the shaft 

 and yet be salubrious at the bottom : besides, the down- 

 ward blast prevents the conveying feeders or jets of gases 

 from particular fissures directly out of the shaft, by turning 

 them into the air-pipes. Of the methods above detailed, 

 the second, by thrilling, appears to me to have a decided 

 advantage, from its constant and extensive powers of venti- 

 lation. 



We will now suppose the shaft or shafts to be sunk 

 down, and a direct communication formed in the mine, 

 and shall now touch upon such a course of proceedings as 

 ought to be adopted to ensure the working of the mine 

 with safety. 



It is generally customary to begin with driving two pa- 

 rallel headings or levels, pretty near to each other, inter- 

 secting the pillar betwixt them by thrils, as often as occa- 

 sion requires, taking care to make up or closely stop the 

 last but one after them in succession. One of these levels is 

 called the air-way, or wind-gate ; and the other, the wag- 

 gon-way, or passage through which the produce of the 

 mine is conveyed to the shaft ; and these are extended to 

 the boundary fixed upon for the workings. 



When other headings are made to communicate with 

 these at right angles, or in any other direction, it is neces- 

 sary to place a close- shutting door, in order to turn the 

 current of air, out of its course, through one branching 

 heading, and back along another. But there is such a va- 

 riety in the modes of working mines, each of which is 

 adapted to peculiar circumstances, that it would be tedious 

 to detail them particularly; neither is it absolutely neces- 

 sary. 



As a great deal of expense may be spared and many ac- 

 cidents avoided^ in situations v/hcxQ fire -damp is prevalent, 



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