which are advanced to bring up 1, 0 is brought up in the second; and the machine itself brings up 0 in the third; after printing this it changes to 101. The process now continues through the successive hundreds in the same manner as before till 999. The back axis is now shifted to the fourth circle, and the three first must be advanced by hand when they require it. At 9999 the back axis is shifted to the fifth circle, and it will serve to 999,999, beyond which it is not required to print.

PILE-ENGINE.

THE pile-engine is a machine by which piles are driven into the ground for the foundation of the piers of bridges, and various other structures.

The method of driving a pile consists in drawing up a very heavy weight, called a ram or hammer, and by disengaging it from the machinery by which it was raised, letting it fall, by the force of gravity, upon the head of the pile. In the most simple machines the weight is drawn up by men pulling a cord over a fixed pulley, and when it has attained a sufficient height allowing the cord to slip from their hands, which permits the weight to descend with considerable force. The two best pile-engines that we have seen are those invented by Mr. Vauloué and Mr. S. Bunce.

Mr. Vauloué's pile-engine may be thus described. A, fig. 306, is a great upright shaft or axle, on which are the great wheel B, and the drum C, turned by horses joined to the bars S S. The wheel B turns the trundle X, on the top of whose axis is the fly O, which serves to regulate the motion, as well as to act against the horses, and to keep them from falling, when the heavy ram Q is discharged to drive the pile P down into the mud in the bottom of the river. The drum C is loose upon the shaft A, but is locked to the wheel, B, by the bolt Y. On this drum the great rope, H H, is wound; one end of the rope being fixed to the drum, and the other to the follower G, to which it is conveyed by the pulleys I and K. In the follower G is contained the tongs F, that take hold of the ram Q, by the staple R, for drawing it up. D is a spiral or fusee fixed to the drum, on which is wound the small rope, T, that goes over the pulley U, under the pulley V, and is fastened to the top of the frame at 7. To the pulley block

is hung the counterpoise W, which hinders the follower G from accelerating as it goes down to take hold of the ram; for, as the follower tends to acquire velocity in its descent, the line T winds downwards upon the fusee upon a larger and larger radius, by which means the counterpoise, W, acts stronger and stronger against it; and so allows it to come down with only a moderate and uniform velocity. The bolt Y locks the drum to the great wheel, being pushed upward by the small lever 2, which goes through a mortise in the shaft A, turns upon a pin in the bar 3, fixed to the great wheel B, and has a weight 4, which always tends to push up the bolt Y, through the wheel into the drum. Lis the great lever turning on the axis m, and resting on the forcing bar 5, 5, which goes through a hollow in the shaft A, and bears up the little lever 2.

By the horses going round, the great rope H is wound about the drum C,

and the ram Q is drawn up by the tongs F, in the follower G, until the tongs come between the inclined planes E, which, by shutting the tongs at the top, opens it at the foot, and discharges the ram, which falls down between the guides b b, upon the pile P, and drives it by a few strokes as far into the mud as it will go, after which the top part is sawed off close to the mud by an engine for that purpose. Immediately after the ram is discharged, the piece 6, upon the follower G, takes hold of the ropes a a, which raises the end of the lever L, and causes its end, N, to descend and press down the forcing bar 5, upon the little lever 2, which, by pulling down the bolt Y, unlocks the drum C from the great wheel B, and then the follower being at liberty comes down by its own weight to the ram, and the lower ends of the tongs slip over the staple R, and the weight of their heads causes them to fall outward and shut upon it. Then the weight 4 pushes up the bolt Y into the drum, which locks it to the great wheel, and so the ram is drawn up as before.

As the follower comes down, it causes the drum to turn backward, and unwinds the rope from it, whilst the horses, great wheel, trundle, and fly, go on with an uninterrupted motion; and as the drum is turning backward, the counterpoise, W, is drawn up, and its rope T, wound upon the spiral fusee D.

There are several holes in the under side of the drum, and the bolt Y, always takes the first of them that it finds, when the drum stops by the falling of the follower upon the ram; until which stoppage the bolt has not time to slip into any of the holes.

The peculiar advantages of this engine are, that the weight called the ram, or hammer, may be raised with the least force; that when it is raised to a proper height, it readily disengages itself and falls with the utmost freedom; that the forceps or tongs are lowered down speedily, and instantly of themselves again lay hold of the ram and lift it up.

This engine was placed upon a barge on the water, and so was easily conveyed to any place desired. The ram was a ton weight; and the guides bb, by which it was let fall were 30 feet high.

Figs. 307 and 308 represent a side and front section of Bunce's pile-engine.

The chief parts are A, fig. 307, which are two endless ropes or chains, connected by cross pieces of iron, B, (fig. 308,) corresponding with two cross grooves diametrically opposite in the wheel C, (fig. 307,) into which they are received, and by which means the rope or chain A is carried round. F, H, K, is a side view of a strong wooden frame movable on the axis H. D is a wheel, over which the chain passes and turns within at the top of the frame. It moves occasionally from F to G, upon the centre H, and is kept in the position F, by the weight I, fixed to the end K. In fig. 309, L is the iron ram, which is connected with the cross pieces by the hook m N is a cylindrical piece of wood suspended at the hook at O, which by sliding freely up the bar that connects the hook to the ram, always brings the hook upright upon the chain when at the bottom of the machine, in the position of G P : see fig. 307.

When the man at S turns the usual crane-work, the ram being connected to the chain and passing between the guides, is drawn up in a perpendicular direction, and when it is near the top of the machine, the projecting bar Q,

of the hook, strikes against a cross piece of wood at R, fig. 307, and consequently discharges the ram; while the weight I of the movable frame instantly draws the upper wheels into the position shown at F, and keeps the chain free of the ram in its descent. The hook, while descending, is prevented from catching the chain by the wooden piece R; for that piece being specifically lighter than the iron weight below, and moving with a less degree of velocity, cannot come into contact with the iron till it is at the bottom and the ram stops. It then falls, and again connects the hook with the chain, which draws up the ram as before.

In this machine, as well as Vauloué's, the motion of the first wheel is interrupted, so that very little time is lost in the operation; with a slight alteration it might be made to work with horses. It has the advantage over Vauloué's engine in point of simplicity; it may be originally constructed at less expense, and is not so liable to be deranged. Both, however, are ingenious performances, and part of their construction might be advantageously introduced into other machines,

BORING MACHINE.

THE boring machine is employed for boring wooden pipes for the conveyance of water, and for boring out the metalline cylinders used in hydraulics, and in pneumatic engines.

The old and common method of boring, is to have a horizontal axis turned round by a mill, at the end of which a borer is fixed, and the cylinder is fastened down upon a carriage, sliding in a direction parallel to its axis, and drawn forwards to the borer by the descent of a weight. The objection to this method is, that any deviation from a rectilineal motion in the carriage, will be transferred to the cylinder, and cause it to be crooked; and that the weight of the borer and its axis acting on the lower side only of the cylinder, causes it to cut away more at that part, and render the metal of the cylinder of unequal thickness. This evil, however, was, in some measure, obviated by a contrivance of Mr. John Smeaton, which was a steel-yard mounted upon a movable wheel carriage, running within the cylinder. By suspending the weight of the cutter and boring-bar from it, the machine was much improved, though still very imperfect.

A boring machine, for metal cylinders, which is not liable to any of these sources of error, is constructed in the manner shown. Fig. 314 is a perspective view of the machine in the action of boring out a cylinder for a steam-engine, the other figures explain the construction of its parts, and