previous shot would be lying where the prop should stand; and in other instances, owing to projections of the side of the workingplace, the prop could not be set near enough to the side to obtain the right direction of the hole. It became necessary, therefore. to supplement the prop with a cross-bar of iron between it and the side of the place, the end of the machine resting against this bar. Old permanent-way fish-plates were found to be suitable For convenience, they were pointed at one end to make the bar fit better against the stone, the other end being fastened by a nail to the prop.

for this purpose.

After a time, this pointed end was driven into a recess made in the stone, and it was found to fasten itself so well that when a stronger bar of iron was pointed with a chisel-end and driven into a hole made about 1 inches deep, by a pick, it was sufficiently firm to stand the thrust of the machine without the aid of a prop to support the other end.

This discovery, at once, very materially increased the facilities of working, and may be said to have brought about the success which has attended the use of this mode of drilling in the Cleveland mines. It rendered unnecessary the props or stands which

were hitherto used, and made it possible to fix the machines so that the holes we.e drilled in the very best position for the advantageous blasting of the stone.

Figs. 1 and 2 (Plate XV.) show the pointed bar, a, of iron driven into the side of the place, and the ratchet-machine set for drilling; b is the barrel of the drill; c, the nut-collar; d, the screw-spindle; e, the ratchet; and, f, the drill-end. The bracket or bar is chisel-pointed at g, and is formed with a number of holes, or countersunk recesses, h, for receiving the barrel-end, i, of the drill.

A remarkable development of the means employed to take advantage of the property possessed by the stone of holding fast the bar of iron driven into it is shown in Figs. 3, 4 and 5 (Plate XV.), a modification designed for use in starting or turningaway places at right angles to the winning-place. The long bar, a, is chisel-pointed at the end, g, j, is a short bar with holes or countersunk recesses, h, and with a socket, k, capable of sliding on the bar, a, to any convenient position. Other modifications will be seen in the illustrations or photographs of the machines in working positions.

RATCHET AND HAND-MACHINE DRILLS.

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While progress was being made in the manner of setting the machines, improvements in the machine itself were not neglected. Clasps were substituted for the loose brasses in the machine shown in Fig. 1, and some time afterwards these were discarded for the improved ratchet-machines of the Hardy Patent Pick Company with the Stayner split-nut (Fig. 6, Plate XV.) for the quick withdrawal of the drills (Fig. 8).

A lighter and fish-bellied

section of drill-steel was

procured, which proved to be a great improvement; and, combined with these, it was found that a square-topped screw with

4 threads to the inch, instead of a Whitworth screw with 7 threads to the inch, whilst increasing the speed of the drilling by 75 per cent., scarcely, if at all, increased the labour.

To obtain the benefit of the weight of the handle and the advantage of the pulling-down stroke when the drill is advancing, which is the case with the machine in the position shown in Fig. 1 (Plate XV.), machines with left-handed screws and drills were obtained for use when the holes were to be drilled on the other side of the working-place (Fig. 8). Each pair of workmen was supplied with two machines, thus enabling them to use the machine best suited to the situation.

RATCHET AND HAND-MACHINE DRILLS.

Many other devices of machine have been tried, such as the pendulum-machine (Fig. 9), which by an arrangement of bevelwheels gave a cutting stroke at each stroke of the handle; the double-handled ratchet-drill (Fig. 7, Plate XV.), and others.

Passing over these, a great advancement was made by the introduction of hand rotary machines for drilling the softer stone; and Messrs. Gray & Tarbitt's machine was introduced at the South Skelton mines (Figs. 10 and 11).

FIG. 14.-HARDY ROTARY DRILLING-MACHINE.

Mr. William Hall's machine is in use at Messrs. Pease & Partners, Skinningrove and Upleatham mines (Fig. 12); and Mr. C. Heslop's machine, more suited to the harder stone, is used at their Lingdale mines. Mr. John Martin, a working miner, introduced a simple, but useful rotary machine at the Skelton mine. Messrs. Blackett, Hutton & Company, the Hardy Patent Pick Company and Messrs. John Livingston & Sons have a large number of their machines in use at several of the Cleveland mines (Figs. 13, 14 and 15).

Fig. 16 shews a miner using a jumper-drill.

Among those who have given so much thought and attention to the development of drilling by ratchet and hand rotary machines

in the Cleveland mines, the names of my assistants, Mr. James Thompson and Mr. William Brooks, deserve particularly to be mentioned.

The usual practice of Cleveland hand-mining is for two miners to work together as mates, one man drilling the holes, charging and firing the shots, while the other man breaks up and fills the stone into the tubs or wagons.

Many experimental trials have been made to ascertain the relative time occupied in drilling by the jumper-drill, the ratchet,

and the hand rotary machine, and in some cases very remarkable results have been obtained. Not wishing to exaggerate the value of the ratchet or hand rotary machines, the writer is keeping well within the mark in stating that two holes can be drilled with these, to one with the jumper-drill; and that, under ordinary conditions, the output per shift of the pair of men can with ease be increased fully 20 per cent.

In addition to this advantage, the diminished amount of physical labour, required in working these machines, enables men to continue mining, who would have been compelled to abandon it, if restricted to the jumper-drill; and it also allows youths,