intended for a single rope or "band," is surmounted by a head-frame carrying one bread pulley of cast-iron, and the whimsey engine is so placed as to be able to serve two shafts at once, raising a loaded "skip" in the one, and lowering an empty one in the other, at the same time. The difficulties of sinking, as regards watery strata, being inconsiderable, except in some few cases, the ingenious and expensive application of wooden or iron tubbing, practised so frequently in the Belgian, and in our northern coal-fields, is almost unknown; and the shafts are lined with brick-work, unless when they pass through strata sufficiently strong to stand permanently without support. The area of the shafts is free from any obstruction, no "guides" being employed to regulate the passage of the "skips" or frames upon which the coal is piled in large masses surrounded by loose "rings," of sheet iron, and from which less than might be expected falls off during the ascent. Ponderous flat chains of three links, alternately short and long, with slips of wood inserted through the long links, are most frequently used for the drawing, and for shafts of moderate depth are very effective and safe.
Taken apart from minor details, the modes of working the mines are two in number, the first applied to the important beds called the "thick coal," and the "new mine;" and the second, termed "long work," (not, like the former, peculiar to the district,) employed in the other coal seams of from two to five feet in thickness, and in the ironstone measures.
The workings of the ten-yard coal are divided into compartments termed sides of work, which are separated from one another by "ribs," or walls of coal, from eight to ten yards thick, and of which no more are kept open at once than can be maintained in activity.
From the main roads, termed gate-roads, each side of work, unless commenced near the outer boundary, is accessible only through a narrow opening, cut, like the gate-road itself, in the lower part of the seam. "Stalls" are then driven out in the coal, each of them eight or ten yards wide, and are crossed again by similar galleries, leaving between them pillars of eight or ten yards square, but varied of course in dimension, according to local circumstances. For additional security during the working, small pillars of three or four yards square at the base, termed men of war, are spared out of the solid coal, wherever it is deemed necessary, to be rapidly prostrated and carried off, when the stall is fully opened. But the driving of the stalls themselves is a work involving no little waste of coal and insecurity to the colliers; the mass of coal of eight yards wide having to be undercut, or holed about a couple of yards in, a large amount of coal is cut up into slack by the "pike," or collier's pick, and the men are exposed to continual risk from falls of coal. As the various portions of the seam are successively "cut" at the side of the stall, and brought down, the colliers have to mount on heaps of slack or light wooden stages, and are necessarily exposed to still greater danger.
There is, in fact, perhaps scarcely any situation more suggestive of feelings of awe, than a side of work in the "thick seam," when a large fall of coal is brought down from the dusky heights of that lofty chamber; the thunder of the falling masses which seem to shake the solid earth and fill the air with a thick cloud of dust, contrasting fearfully with the dead silence which ensues, and which the hardy colliers scarce break by a whisper, whilst in suspense they listen for the slightest crack which might portend a farther fall.
When a compartment has thus been cleared and the large pillars sometimes a little thinned, the "slack" or small coal and dust is left in
