Mr. Bubble's Account of the Explosion in Jarro'w Colliery. 189 



All requisite measures were, therefore, taken to ensure a powerful 

 ventilation in that part of the colliery — the drifts of access through the 

 Dykes were completed, and the working of the Coal beyond them com- 

 menced in July, 1829. 



In the course of prosecuting the workings to the south, another suc- 

 cession of small Dykes was met with, which depressed the seam about 

 7 feet, and access through which, for the roily-way, was formed by 

 the stone drift, represented on the section. 



Contrary, however, to expectation, and to the agreeable surprise of 

 every one, scarcely any inflammable air appeared, either in the Coal or 

 in crossing the fissures of the several Dykes. And, from that period, 

 until within a few weeks of the accident, the workings continued in 

 this harmless state. The presence of inflammable air having scarcely 

 ever been discernible in any part of them. 



About five or six weeks preceding the accident, a slight discharge of 

 inflammable air from the Coal, began to appear in the east drifts — see 

 Plan, Plate XVIII., which continued, with little variation, up to the time 

 of the accident. This discharge of gas never increased to such an extent 

 as to excite alarm, or to require any extraordinary measures of precau- 

 tion, to be resorted to. 



The whole tract of workings, in this district, is but of limited extent, 

 and the distribution of the current of atmospherical air, as represent- 

 ed on the Plan, Plate XVIIL, ensured an ample supply of cool, fresh air, 

 and a copious ventilation in every part of the workings. 



The current of fresh air was carried from the bottom of the pit along 

 the rail-way, to the top of the Drewitt engine inclined plane stone 

 drift — through which it continued to the west drifts at X. Here the 

 current was equally divided into two branches — one of which venti- 

 lated the first division of west workings, and the other continued straight 

 forward along the headways, into the second division of west workings, 

 which it ventilated, and passing through to the face of the south head- 

 ways, returned by the east workings and east drifts into the back win- 

 ning headways at Z, along which it ran, and united with the first branch 

 at A, after which the united current proceeded to the-upcast shaft. The 



