Mr. Buddle's Account of the Explosion in Jarrow Colliery. 187 



casualty, which I attribute to the escape of the gas upwards, through 

 the fractured strata. The breaking of the strata, by the working of 

 the pillars below, is plainly proved by the sinking of the ground at 

 the surface, immediately above the places where the Coal has been 

 extracted. 



It is generally observable after a discharge of inflammable air, from the 

 fissures in the roof, on the falling of the barometer, that, on its taking 

 to rise again, the discharge of inflammable air not only ceases, but that 

 a strong in-draught of the atmospherical air immediately ensues. I 

 have frequently placed a candle at the orifices of the fissures, on the 

 rising of the barometer, and generally found the flame drawn in with 

 considerable force. 



Third — by cavities, or large fissures, which do not seem to have any 

 outlet. 



This may be considered- the most dangerous case, as it frequently 

 happens that a large quantity of gas bursts out from those cavities, 

 which occur in the roof and pavement, as well as in the Coal. When 

 they occur in the latter, it generally happens where the seam is inter- 

 sected by a " Hitch," or small Slip Dyke — or at the fissure of a large 

 Slip Dyke. 



The great danger in this case arises from the suddenness and great 

 force of the eruption, without giving sufiicient warning for the escape 

 of the colliers, or for allowing the persons in charge of them time to 

 adopt the necessary measures of precaution. Many accidents have 

 happened from this cause, but there have also been innumerable in- 

 stances of escape from it. The technical name adopted by our colliers 

 for this sort of occurrence, is "a bag of foulness." 



The explosion of the I pit, Washington Colliery, on the 20th of 

 November, 1828, was occasioned by "a bag of foulness" breaking 

 down from the roof of the air-course hoard, behind the workmen — which, 

 at the same time, stopped the ventilation, by the fall of the roof it oc- 

 casioned. So that a double cause operated in this instance to occasion 

 the explosion — the stoppage of the ventilation, and an enormous dis= 

 charge of inflammable air occurring at the same instant. 



