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cavated. In Yorkshire, coal is wrought in what is called the 

 long method. In Durham and Northumberland, now chiefly 

 in panel-work, the air being '-^coursed'' up and down each 

 panel, and then from one panel to another. 



There are two modifications of the Yorkshire or long 

 method, used according as the mine abounds in fire-damp, 

 the nature of the roof, &c. One is with single board-gates, 

 the air being drawn from one to another across the benks 

 where the men are working, and is used where there is little 

 fire-damp. Another with double board-gates, the air being 

 coursed up one and down another, and drawn across the 

 benks where the men are working. There is another differ- 

 ence in working the benks ; one is to begin at the far end of 

 the works or towards the basset of the coal, and work it out 

 down towards the pits sunk ; and the other to begin near the 

 levels, and work towards the basset. In some pits, also, the 

 whole of the air coming down the downcast pit, is sent in one 

 body round the whole of the workings ; in others, one-half 

 goes on one side of the pit, and the other half on the other. 



It may be true that each of these methods, used only 

 where each ought to be used, may be safe, and that many 

 collieries in Yorkshire have for years been worked under 

 them without any accident ; but this does not prove that 

 either of these systems is the best, provided any other can 

 be shown to be safer and equally practicable. The great 

 objection to the Yorkshire system is, that where the whole 

 air sent down ventilates in one body the whole mine, if a 

 considerable explosion takes place in any part of it, nearly 

 the whole of the persons usually perish ; the ventilation is 

 stopped, and those who are not burnt or killed by the force 

 of the explosion, are suffocated for the want of pure air. 

 The same objection applies, though with less force, where 

 the air is divided only into two parts ; the persons in the 

 one-half exploded must nearly all perish. 



