lf-a-mile, or even a mile, for
the whole of which length a gallery would have to be cut, from which,
side workings would extend on either side. So accurately did Mark note
all he saw, that on his return home he was able to draw out a plan of
the mine, with which the under-viewer was so pleased, that he took it to
the manager.

"This boy deserves encouragement. We must see what can be done for
him!" was the remark. Shortly after this, great improvements were
introduced into the mine. Fresh shafts were sunk, for affording better
ventilation, and for more rapidly getting the coal to the surface. Near
them, engines of great power were placed to perform the various
operations required. An endless wire rope was made to run from the
shafts to the extreme end of the gallery, kept revolving by a
steam-engine down in the mine. The man walking ahead of the leading
waggon, to which is secured a pair of iron tongs, grips hold by them of
this endless rope, which thus drags on his waggons without any labour on
his part, towards the shaft, up which the coals are to be carried to the
surface. The chief gallery was divided by a wall down the centre, with
openings at intervals of twenty yards or so, to enable persons to pass
through. There were also niches on either side, where he could stand
while a train was passing. On one side of the gallery the full trains
ran along on rails from the workings to the shaft; on the other side the
empty waggons returned to the workings to be filled. For the purpose of
better ventilating the mine, an enormous fan, forty feet in diameter,
formed like the paddle-wheels of a steam-ship, and kept constantly
revolving by steam-power, was placed over a shaft sunk for that sole
object. The suction caused by the enormous paddles drew up all the foul
air and noxious vapours from the whole of the mine, and at the same time
drew in from another shaft, more than a mile distant, a current of fresh
air, amounting from 70,000 to 80,000 feet per minute, thus doing the
work of a furnace far more effectually, and at much less cost.

Instead of the old corve or basket, an iron safety-cage had been
introduced, sliding up and down on steel bars, resembling indeed a
perpendicular rail-road. Wonderfully changed was the appearance of the
mine itself. Mark, who had been employed above ground for some time,
was astonished, on being lowered in the new safety-cage, to find himself
on stepping out at the bottom in a s