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 b b, 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 GP: 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

are drawn to a scale. In fig. 314, A A denote two oak ground sills, which are firmly bolted down, parallel to each other, upon sleepers let into the ground. At each end of these a vertical iron frame, B B, is erected, to support the gudgeons at the end of a long cylindrical axis, DD, which is turned round by the mill. The cylinder LL, which is to be bored, is fixed immovable over the bar, and exactly concentric with it. A piece of castiron KK, LL, (figs. 310, 312, and 313,) called a cutter-head, slides upon the axis, and has fixed into it the knives or steelings fff, which perform the boring. This cutter-head is moved along the bar by machinery, to be hereafter described; by means of which it is drawn or forced through the cylinder, at the same time that it turns round with the axis D. The steel cutters will necessarily cut away any protuberant metal which projects within the cylinder, in the circle which they describe by their motion, but cannot possibly take any more.

The cylinder is held down upon an adjustable framing, which is ready adapted to receive a cylinder of any size within certain limits. Pieces of iron, E E, are bolted down to the ground sills, having grooves through them to receive bolts, which fasten down two horizontal pieces of cast-iron FF, at right angles to them. These horizontal pieces support four movable upright standards GG, which include the diameter of the cylinder L L, which is supported upon blocks, bb, below, and held fast by iron bands a a, drawn by screws in the top of the standards GG. The cylinder is adjusted, to be concentric with the axis D D, and held firmly in its place by means of wedges driven under the blocks and the standards.

To explain the mechanism by which the cutters are advanced, we must refer to figs. 311, 312, and 313, by the inspection of which it will be seen that the axis DD is, in fact, a tube of cast-iron, hollow throughout, It is divided by a longitudinal aperture cc, fig. 310, on each side. At the ends of it is left a complete tube, to keep the two valves together. The cutter-head KK, LL, consists of two parts; of a tube K fitted upon the axis D with the greatest accuracy, and of a cast-iron ring LL, fixed upon KK by four wedges. On its circumference are eight notches, to receive the cutters or steelings ff, which are held in and adjusted by wedges, The slider K is kept from slipping round with the axis, by means of two short iron bars e e, which are put through to the axis, and received into notches cut in the ends of the sliders KK. These bars have holes in the middle of them to permit a bolt at the end of the toothed rack L to pass through. A key is put through the end of the bolt, which, at the same time, prevents the rack being drawn back, and holds the cross bars ee in their places. The rack is moved by the teeth of a pinion N, and is kept to its place by the roller O; the axis of the pinion and roller being supported in a framing attached to the standard BB, as shown in a perspective view of the machine in fig. 314. The pinion is turned round by a lever, put upon the square end of the axis, and loaded with the weight P, that it may have a constant tendency to draw the cutter through the cylinder. This lever is capable of being put on the square end of the axis either way, so as to force the rack back into the cylinder if neces

sary.

In some boring machines, another contrivance, superior perhaps to what we have now described, is employed to draw the cutter through the cylinder. It consists of four small wheels, one of which is fixed at the right-hand extremity, D, of the bar DD, fig. 314. Another pinion is fastened on the extremity of an axis, analogous to the rack M, having at its other extremity a small screw, which works in a female screw, fixed to the cutter K K at e, fig. 310. Below the second pinion is another, con

taining the same number of teeth, and fixed on a horizontal axis pa rallel to D D. At the other end of this axis is a fourth pinion, which is drawn by the first pinion at the end of the hollow axis D D. The first pinion has twenty-six teeth, the fourth thirty, and the second and third may have any number, provided they are equal. As the axis D revolves, the first pinion fixed on its extremity draws the fourth, which by means of the third, fixed on the same axis with it, gives motion to the second. The second pinion being fixed to an axis within DD, unscrews the screw at its other extremity, and of course makes the cutter advance along the cylinder. This screw has eight threads in an inch, and sixty turns of the axis are required to cut one inch.

To introduce a cylinder into its place in the machine, it is necessary to remove the upper braces, 17, of the bearings upon the standards BB; and by supporting the axis upon blocks placed under the middle of it, the standard, with the pinion N, and roller frame, is removed by taking up the nuts which fasten it to the ground sills A A, the rack M being supposed previously withdrawn. A cutter-block L, of a proper size to bore out the intended cylinder, is now placed upon the slider K, fig. 313, and wedged fast. The cutter-head is then moved to the farther end of the axis, and the cylinder lifted into its place. The standard B is returned, and the whole machine brought to the state of fig. 314, the cylinder being, by estimation, adjudged concentric with the axis D. Two bars of iron are now wedged into the cc in the axis, and applied to the ends of the cylinder; while the axis is turned round they act as compasses to prove the concentricity of the cylinder. Small iron wedges are drawn round its cylinder to adjust it with the utmost accuracy; and in this state the cylinder is ready for boring.

The next operation is felling the cutters, which are fastened into the block L by wedges, and adjusted by turning the axis round, to ascertain that they all describe the same circle. The boring now commences by putting the mill and axis in motion, and the machine requires no attention, except that the weight P is lifted up as often as it descends by the motion of the cutters or steelings. When the cutters are drawn down through the cylinder, they are set to a circle a small quantity larger, and returned through the cylinder a second time. For common work these operations are sufficient; but the best cylinders are bored many times, in order to bring them to a proper cylindrical surface. The last operation is turning the flanch n of the cylinder perfectly flat, by wedging a proper cutter into the head. This is of great importance to ensure that the lid will fit perpendicular to the axis of the cylinder. The cylinder is now finished and removed.

The accuracy of this machine depends on the boring bar, DD, being turned upon its own gudgeons; and if it is turned to the same diameter throughout, it will certainly be perfectly straight. While the axis is in the operation of turn. ing, a piece of hard wood should be fitted into the grooves of the cylinder. The slider K is first bored out, and

afterwards ground upon the axis with emery to fit as true as possible.

The elevation of a mill proper for moving two of these machines, is represented in fig. 310. The pinion 30 is supposed to be on the axis of a water-wheel, and turns the two wheels 60, 60, which have projecting axes, with a cross-cut similar to the head of a screw, as is shown in the figure.

The ends of the boring axes have similar notches, and by putting keys in between them, the motion may be communicated or discontinued at pleasure, by the removal of the key.

FILE-CUTTING MACHINE.

THERE have been various contrivances for this purpose; but the best we are acquainted with is described in the Transactions of the American Philosophical Society, and is as follows:

AAAA, fig. 315, is a bench of seasoned oak, the face of which is planed very smooth. BBBB the feet of the bench, which should be substantial. CCCC the carriage on which the files are laid, which moves along the face of the bench A A A A, parallel to its sides, and carries the files gradually under the edge of the cutter or chisel H H, while the teeth are cut: this carriage is made to move by a contrivance somewhat similar to that which carries the log against the saw of a saw-mill, as will be more particularly described. DDD are three iron rods inserted into the ends of the carriage CCC C, and passing through the holes in the studs E E E, which are screwed firmly against the ends of the bench A A A A, for directing the course of the carriage CCCC, parallel to the sides of the bench. FF two upright pillars, mortised firmly into the bench A A A A, nearly equidistant from each end of it, near the edge, and directly opposite to each other. G the lever or arm which carries the cutter H H, (fixed by the screw I,) and works on the centres of two screws K K, which are fixed into the two pillars FF, in a direction right across the bench A A A A. By tightening or loosening these screws, the arm which carries the chisel may be made to work more or less steadily. Lis the regulating screw, by means of which the files may be made coarser or finer; this screw works in a stud M, which is screwed firmly upon the top of the stud F; the lower end of the screw L bears against the upper part of the arm G, and limits the height to which it can rise. N is a steel spring, one end of which is screwed to the other pillar F, and the other end presses against the pillar O, which is fixed upon the arm G; by its pressure it forces the said arm upwards until it meets with the regulating screw L. P is an arm with a claw at one end marked 6, the other end is fixed by a join: into the end of the stud or pillar O, and, by the motion of the arm G, is made to move the ratch-wheel Q. This ratch-wheel is fixed upon an axis, which carries a small trundle-head or pinion R, on the opposite end; this takes into a piece S S, which is indented with teeth, and screwed firmly against one side of the carriage CCCC; by means of this piece motion is communicated to the carriage. F is a clamp for fastening one end of the file ZZ in the place or bed on which it is to be cut. V is another