348 



Mr. Huddle's Narrative of the Explosion 



ascertained that it requires fourteen or fifteen volumes of atmospheric air to 

 dilute one volume of the carburetted hydrogen of our collieries below the 

 point of explosion. It, therefore, follows, that to place any colliery in a safe 

 working state, requires fourteen or fifteen times as much atmospheric air 

 to be passed through the workings, as they produce of gas. But this is 

 not all, this current of air must be earned through every part of the mine 

 where gas is to be found, so as to prevent accumulations ; otherwise, no 

 current of air, however, powerful, would render the workings safe from ex- 

 plosion. It is the impossibility of preventing such accumulations of gas, 

 in collieries working pillars which renders them more liable to heavy explo- 

 sions. 



The first step towards the ventilation of a colliery is, to introduce a pow- 

 erful current of atmospheric air into it. The next is to regulate and con- 

 duct that current into the several workings and ramifications of the mine 

 as circumstances may require. I shall only state, in this place, the various 

 means by which the former is effected, as the latter will be explained in 

 the sequel. 



The ventilation of mines is sometimes effected by the natural operation 

 of the atmosphere ; as, for example, when two pits are situated upon dif- 

 ferent surface levels, the rise of the ground being more than the rise of the 

 seam between them, as represented in the diagram. In this case the top of 



the Pit A being lower than the top of the Pit B, supposing the atmos- 

 phere to be in a quiescent state, and the temperature of the air to be 



