STEAM BORING MACHINE FOR QUARRIES, —amp;c.—mdash;The annexed engravings are views of STEAM BORING MACHINE FOR QUARRIES, —amp;c.—mdash;The annexed engravings are views of steam machinery for boring by M. Cave, of Paris, a celebrated French engineer, and which has been illustrated in the " London Artisan." For the great majority ot mining, quarrying, and tunnelling operations, boring and blasting is employed, and it is for this object that M. Cave's machinery is designed. It consists of a cylinder and piston actuated by steam, compressed air, or by the vacuum system, the cutting tools being attached to the piston-rod, and acting by percussion. It thus resembles a Nasmyth's steam hammer; and a similar means is employed to destroy the momentum of the piston, by enclosing a portion of steam or air, which acts as a cush ion at each end of the cylinder. To carry out this purpose, the inlet aria exhaust passages are kept quite distinct, as will be seen on re ferring to the drawings. Figure 1 is an elevation of the machine in section through the inlet passages ; figure 2 is an elevation of the cylinder in section through the outlet passages; figured is a front eleva tion, showing the passages; and figure 4 is a plan in section through the passages. J is the cylinder, containing the piston, K, to the rod of which is attached a cross-head, N, to which is also fixed the chisel, M. The cross-head arid chisel are guided by the guide-rods, 0 0, which are fixed in a plate dovetailed into the cylinder cover, in such a manner, that it can be freely turned round (with the piston). by means of the handles, P Q, and thus enable the chisel to take a fresh cut at every stroke, without which it would jam. The annexed sketches show the shape of the chisel and its cutting edge. The admission and emission of the com pressed air or steam is regulated by a four-way cock, R, supplied by a pipe, T, as shown in figure 1. The air is admitted through the inlet passage, a,, on the top of the piston, which will rapidly descend, until it passes the outlet, a', figure 2, when, the further escape of air being prevented, the piston is stopped by the air-cushion. On the up-stroke, the cock having been turned, the compressed air enters by the passage, b, and escapes by the passage, b'. It will be observed that the plug of the cock is divided transversely by a dia phragm, shown in fig. 4, to keep the passages distinct, c and d answering to the two inlet passages, and t and f to the two outlets. The air which escapes by the cylinder is led, by the pipe, t, to near the point of the chisel, and will have the effect of blowing away the small chips loosened by the chisel. The machine is shown in "the engraving as working vertically; but it could obviously be applied to driving a level, by placing it hori zontally and mounting it on a carriage. If it be desired to bore a hole of larger dia meter than the width of a chisel, the cutter can be fixed at any desired distance from the centre of the piston-rod, the revolution of which will cause the cutter to describe a cir cle of corresponding diameter. For sinking shafts, a number of cylinders might be employed simultaneously, working a sufficient number of chisels to extend round the shaft; and the same arrangement applied horizontally would serve to drive a level.—mdash; In vertical boring the chisels have to be regu larly withdrawn, in order to permit ot the extraction of the debris; but we do not find that the author has provided any special means for effecting this object. He has suggested that the electro-magnetic power may be applied to work this machine ry; but air appears to offer the most tangible advantages. It can be conducted a great dis tance without suffering condensation, as steam does; and it would materially improve the atmosphere ot the mine, by blowing in fresh air, or, if worked on the vacuum system, it would be equally advantageous in coal mines, by serving to draw off the fire-damp.