118 Mr Bald mi the Fires that take place in Collieries. 



two feel deep, in the opposite sides of the pit, and into these 

 grooves logs of wood thirteen inches upon the side were laid as 

 a floor across the volume of the pit; these were covered transverse- 

 ly with boards, and over this was laid a well wrought clay pud- 

 dle eight feet thick ; and in order that the accumulated water of 

 the mines might be drawn off at pleasure, cast-iron pipes with 

 valves at top opening upwards, were inserted through the scaf- 

 folding and puddle, in two of the pits toward the dip, and a 

 rope from each of the valves was secured near the mouth of each 

 pit. These pipes had a collar cast upon them, so as the pipe 

 might rest upon the face of the scaffolding. 



The section of the colliery is represented figure 5, Plate III ; 

 and the timber scaffolding with ihe clay puddle, pipe and valve, 

 are represented figure 6, Plate III. 



While the burning was going on progressively, the fresh air 

 descended the pit a, figure 5, passed through the burning mass 

 at c, and the vapour and smoke ascended the pit b, in a mode- 

 rate volume and slowly. In this pit b, there was a stair for the 

 men descending to the mines, and as this was the pit to the 

 rise, or crop, the air, as a natural consequence, always ascended by 

 that pit. But as the communication below the eight feet coal 

 at the pit b had to be stopped, it was altogether impossible to 

 accomplish this while the stair remained in it, and no man durst 

 venture down one fathom without losing his life. It therefore be- 

 came necessary to reverse the current of air, so that the fresh 

 air might descend the pit b, and ascend by the dip pit a, 

 contrary to its natural course. To effect this, a large iron 

 grate, capable of holding nearly a ton of burning coals, was sus- 

 pended by a chain in the shaft a ; the pit b was then covered 

 over at the top, until the shaft a became heated by the fire in 

 the grate ; then the scaffolding was quickly removed from the 

 mouth of the pit b, and the reverse circulation instantly took 

 place. The miners then with perfect safety removed the stair — 

 cut off the communication to the splint coal at the pavement of 

 the eight feet coal, — and this being accomplished, the grate 

 with the fire, was removed from the pit «, and the circulation 

 returned to its ordinar}' course. Meantime, the water being 

 prevented from descending to the splint coal by means of the 

 caffoldings and clay-puddles, it accumulated in the waste, 



