ied by the pumping engine.

The Vaughan was worked by a single shaft divided by a strong wooden
partition into two, one of these known as the downcast shaft, that is,
the shaft through which the air descends into the mine, the other the
upcast, through which the current, having made its way through all the
windings and turnings of the roadways below, again ascends to the
surface. This system of working by a single shaft, however, is very
dangerous, as, in the event of an explosion, both shafts may become
involved in the disaster and there will be no means of getting at the
imprisoned miners. Nowadays all well-regulated mines have two shafts,
one at a distance from the other, but this was less common thirty years
back, and the Vaughan, like most of its neighbours, was worked with a
single shaft.

Each miner before descending went to the lamp-room and received a
lighted "Davy." As almost every one is aware, the principle of this
lamp, and indeed of all that have since been invented, is that flame
will not pass through a close wire-gauze. The lamp is surrounded with
this gauze, and although, should the air be filled with gas to an
explosive point, it will ignite if it comes in contact with flame, the
gauze prevents the light of the lamp from exploding the gas-charged air
outside. When the air is of a very explosive character even the
Davy-lamps have to be extinguished, as the heat caused by the frequent
ignitions within the lamp raises the gauze to a red heat, and the gas
beyond will take fire.

Jack took his place in the cage with Bill Haden and as many others as it
could contain. He gave a little start as he felt a sudden sinking; the
sides of the shaft seemed to shoot up all round him, wet, shining, and
black. A few seconds and the light of day had vanished, and they were in
darkness, save that overhead was a square blue patch of sky every moment
diminishing in size.

"Be'st afeard, Jack?" Bill Haden asked, raising his lamp so as to get a
sight of the boy's face.

"Noa, why should I?" Jack said; "I heard 'ee say that the ropes were new
last month, so there ain't nothin to be afeard on!"

"That is the young un they call Bull-dog, ain't it, Bill?"

"Ay!" Bill Haden answered; "he's game, he is; you can't make him yelp.
I've licked him till I was tired, but he never whimpered. Now then, out
you go;" and as the cage stopped the men all stepped out and started for
the places in which they were working.

"Coom along,