headings are driven out from the main level at such an angle of obliquity as to be convenient for horse-roads, whilst from the latter the working stalls are opened, narrow at the entrance (to protect the roads), and wider inside. The pillars between them are left so narrow that they are sure to be much crushed; and though some portions of them may be robbed, a large amount is wasted. The ventilation becomes irregular and difficult, and many accidents arise.

A last variety remains to be mentioned, viz., the "square work," employed for the getting of the magnificent seam, varying from 25 to 36 feet thick, called the Dudley Thick or 10-yard coal. The shafts are sunk to the bottom of the seam, and a main way, the gate-road, is carried forward in its lower coals, ventilated by means of a separate air-head or drift of very small dimensions opened in the coal also, at a few feet on one side of, or above the gate-road.

From this latter the main workings, called sides of work, are opened in the form of a square or parallelo

Fig. 20. Square work, South Staffordshire. Scale, 2 chains to the inch.
A, bolt-hole; B B, pillars.

gram, 50 yards in the side, or more, and shut off by a rib of coal or 8 yards thick, at the least, from all

other workings, except at the entrance, a narrow bolthole. Driving out in the lower coals, and gradually rising to the higher ones, the colliers open stalls of 5 to 8 or 10 yards wide, forward and across, so as to leave square pillars, generally 9 or 10 yards in the side, and whenever the unsoundness of coal or roof appears to require it, sparing additional supports of coal in men-of-war 3 or 4 yards square.

The men get at the upper divisions of the seam by standing on the slack and coal already cut, or on light scaffolding. No ordinary timbering can be used to support so high a roof, nor can the eye in these vast and murky chambers easily detect where special danger threatens overhead; but the sense of hearing comes valuably into play, and a sharp ear often catches the preliminary cracking which indicates the approach of a fall. Nevertheless, the work is the most dangerous in which the collier can be engaged; and no mode of getting this coal with a less serious destruction of life by "falls" has been devised, except that of working it in two "lifts," by the long-wall method, which, in despite of much opposition, appears, at a few works, to have stood successfully the result of many years' practice.

The pillars in the "square work" are often in conclusion thinned to a smaller size, and when at length the roof begins to break in, the side of work is abandoned, a dam put into the bolt-hole, and thus the air is excluded from the heaps of waste small coal, and the crush prevented by the ribs from extending to other parts of the pit.

It scarcely needs to be added, that although after this first working, operations may be set on foot for

getting ribs and pillars, much of the coal is so crushed or "frenzied" as to be of little use. The waste of some thousands of tons of coal per acre, and the great sacrifice of human life in the process, lead one to contemplate with no pride or satisfaction our mid-English working of the finest seam of coal in Europe.*

Some of the coal seams of central France, although more broken up than the last, are much thicker, and have led to many varieties of working, in order to find out the safest and best. In the Department of the Saône et Loire, I learnt on a recent visit that every other mode has given place to the working by remblais, i.e., taking a horizontal slice of 2 metres in height across the seam, and filling up the space with stone and earth brought down from the surface. At Montceat, near Blanzy, I found the seam to be no less than 78 feet thick, inclined at about 20 degrees. The works are carried forward horizontally from floor to roof, 6 feet 6 inches high, alternating with "middlings" of coal of the same height; and within a few months of the working and stowage of one horizon, fresh openings are made in the range below, and the remblais or stowage is found to be so closely packed as to form a very good roof for driving under-assuming the use of plenty of timber. The plan of the working is in pillars of 10 metres wide, which are sliced off as in long-wall working.

The LONG-WALL method may be applied, either by

The daily and hourly risk to which the men are subject in this district from falls of roof and coal alone may be inferred from the results of the inspector's inquiries.

Deaths from "falls" in South Staffordshire and East Worcestershire:-1856, 88; 1857, 81; 1858, 97; 1859, 92; 1860, 75; 1861, 78; 1862, 79; 1863, 55.

driving out roads in the solid coal to the extremities, and then working back, leaving nothing but goaf or gob

The portion A represents advancing stalls, or tooth-work, taking the face of the coal; the side B works in the end of the coal, whilst the part C D is carried in a straight line irrespective of the cleat. The double edge of the gob-roads represents the pack-walls.

behind, or, by commencing at once near the shaft, to work away the mineral, maintaining means of access to its fresh face by roads, artificially supported, through the waste. Beyond this, great differences occur, according as to whether the faces of work need to be straight, following the lines of cleat, or are divided into "stalls," or may be set off in several directions at once. The working faces are for the most part so arranged as to advance against the planes of cleat; but there are certain tender coals in which it will be found that when the pit is deep, they are upon this system

much broken up by the pressure, and that a far better proportion of round coal will be obtained by working on the end, i.e., in the direction of such cleat. The most regularly laid out varieties of long-wall are those of Shropshire, Leicestershire, and Derbyshire; but others, more or less modified to suit local requirements, may be seen in Lancashire, Somersetshire, Dean Forest, South Wales, Scotland, Belgium, and Saxony.

Without exceeding the limits of a book like the present, it would be impossible to dwell upon the details of the various kinds of long-work, but the diagram, Fig. 21, may show some of the chief features of several plans of arrangement diverging from one pair of pits.

In some instances it will be seen that a great length of face may be opened in a single line, as much indeed as 100 to 400 yards; in others 30, 40, or 50 yards of straight face form a stall, and one such is followed up closely by another. In many instances again, the face forms on the large scale a curvilinear working, which may be adopted when the coal is not so divided by cleat or backs as to cut more freely one way than another.

Let us now turn our attention to the "face or front of the working, which, as it is but a few feet or yards away from the waste, where the roof has "come down," requires to be carefully protected. The usual way is to plant a double row of props (sometimes three rows are needed) arranged alternately, and at right angles to the roof and floor. Each prop takes a good bearing on the roof, by carrying a piece of wood, the lid or tymp, 12 or 15 inches long, which first receives the pressure, and is soon squeezed or broken. Cast iron has been occasionally employed for the purpose, but the props