S2 Messrs, Faraday and Lyell on 



into that part of the return where the goaf pipe entered, would 

 be sufficient alone or not, is a pc«nt which must depend on 

 the nature of the works, and must be determined, if deter- 

 mined at all, by experience. 



Such is the general plan, which, with some degree of con- 

 fidence in its principles, we venture to submit to practical men 

 for their consideration ; and we do it with more readiness, 

 believing, from the spirit which we have seen manifested at 

 the Haswell mine, that they are earnestly desirous of carrying 

 into effect everything that can be practically useful. The 

 effect of it would be to remove that condition of the goaf at- 

 mosphere, which ordinarily exists at the upper edge of the 

 goaf basin, to a distance of four, five, or more feet higher up 

 within the basin, so as to allow abundant space for all the va- 

 riations of this atmosphere, without the underflowing of any 

 explosive, or perhaps even contaminated portion of it into the 

 mine. In the case of a regular mine working downwards or 

 into deeper parts, there does not seem much difficulty of ap- 

 plication, since thehighest edgeof the goaf is there stationary. 

 Where the pitmen work towards the rise or upwards, as is the 

 case at the Haswell Little Pit, then the goaf end of the pipe 

 must change its place from time to time. Where faults occur, 

 and the mine is irregular in its workings, each case must be 

 considered by itself, and met, if it can be, upon the same prin- 

 ciples. The more faults there are in a mine, the more diffi- 

 cult it may be to regulate the place and form of the upper 

 edge of the goaf cavity ; but on the other hand, the more 

 faults there are, the more fire-damp is there generally in the 

 workings, and therefore the more occasion for some means of 

 obtaining the end proposed. If, as is manifested by the Has- 

 well Pit, mines considered the most safe and best ventilated need 

 some such means, how much more must others require it ! 



It would be a very important addition to the information 

 requisite to indicate and lead to the fittest means of guarding 

 against such events as that at the Haswell Pit, if the state of the 

 atmosphere in the goaf vault were from time to time examined, 

 and especially upon fallings of the bai'ometer ; so that we might 

 have a general knowledge of its nature. This would not be 

 at all difficult in the hands of an intelligent man ; for a piece 

 of small copper pipe about one-third of an inch in diameter, 

 and 25 or 30 feet in length, might easily be introduced by 

 hand into the cavity of the goaf, at the place where the edge 

 is highest, and this being attached to an air-pump syringe 

 below, a few strokes of the hand would suffice to make the 

 latter bring down the gas or air from the place reached by the 

 upper end of the pipe ; and if, after the pipe and syringe were 



