OQ H, is fixed an inverted piston B D, with its bucket and valve upon the top at D. Upon the top of the barrel there goes off a part FR, either fixed to the barrel, or movable by a ball and socket; but in either case water and air tight. In this part, at C, is a fixed valve opening upwards. It is evident that when the piston frame is thrust down into the water, the piston D descends, and the water below will rush up through the valve D, and get above the piston; and that, when the frame is lifted up, the piston will force the water through the valve C up into the cistern P, there to run off by the spout. The piston of this pump plays below the surface of the water. Mr. Martin has described a mercurial pump, which works by quicksilver, invented by Mr. Hoskins, and perfected by Mr. Desaguliers; and another pump of the lifting sort, invented by Messrs. Gosset and De la Deville, and set up in the king of France's garden at Paris, the piston of which works without friction.-Phil. Brit. vol. ii. p. 57, &c. ed. 3.

6. Ctesibius's pump, the first of all the kinds, acts both by suction and pulsion.

Its structure and action are as follows: A brass cylinder A B CD, fig. 227, furnished with a valve in L, is placed in the water. In this is fitted an embolus MK, made of green wood, which will not swell in the water, and adjusted to the aperture of the cylinder with a covering of leather, but without any valve. In H is fitted on another tube N H, with a valve that opens upwards in I.

Now the embolus M K being raised, the water opens the valve in L, and rises into the cavity of the cylinder; and when the same embolus is again depressed, the valve I is opened, and the water driven up through the tube H N.

This is the pump used among the ancients, and that from which both the others are deduced. Sir S. Morland has endeavoured to increase its force by lessening the friction, which he has done to good effect, insomuch as to make it work without almost any friction at all.

7. In 1813, the Society for the Encouragement of Arts conferred a silver medal on Mr. John Stevens, for an improvement in the construction of the forcing-pump, by which he is enabled, at a comparatively trifling expense, to raise water from a well 66 feet below the surface of the ground. The whole expense of the pump and apparatus was 251,

The lower part of the pump-tree is four inches in the bore. The lower part of the rod which passes through the stuffingbox is made of brass; the elbow and upper pump-trees are of a two-inch bore, and may be easily made of any kind of wood. It may also be made to act as an engine to extinguish fires, by the addition of an air-tight vessel and pipe to the upper part.

In the drawing is introduced a cap and screw, in preference to screwing it to the nozle of the pump, as it is stronger and more to be depended upon; and when the water is to be raised a great height, a screw is also recommended to be

made to fit the nozle, that every thing may be always ready for immediate use. The work of this pump is not liable to be injured by frost; and when the well is of considerable depth a brass or metal barrel for the piston to work in should be adopted.

Fig. 228 is a section of a well, in which a pump of this kind is fixed; A A represents the surface of the ground, and BB the brickwork of the well, in which the water stands at the level C, and is, by the pump, to be raised to the surface A A.

D is the lever or handle of the pump, which has the rod a jointed to it, and descending to the pump; the rod is made of wood, in several lengths, which are united by joints of iron, in the manner shown at fig. 229; the wooden rods, a a, being capped with iron forks b, which include the ends of them and are rivetted fast; the ends of the forks are joined together to connect the several lengths.

F is the working barrel, or chamber, of the pump, in which the bucket works; this part is formed of a tree, bored through and having a projecting Branch e, which is likewise bored obliquely to the barrel, and forms the forcing pipe; in the bottom of the barrel the suction-valve is situated, being at the top of the suction part of the pump, which is bored with a smaller auger than the working chamber, which is also lined with a brass tube, where the bucket works. The top of the barrel is covered by a metal lid, g, (see figs. 230 and 231,) which has a stuffing-box in the centre to receive the metal cylindrical part of the pump-rod h; to the lower extremity of this the bucket a is fixed. The metal lid consists of a ring, which is screwed to the wooden barrel by five screw-bolts, passing through as many ears, pro jecting from the circumference of the ring; they have eyes below to hook upon pins, which are fixed in the wood, but project sufficiently for these bolts to hold, and are formed into screws above, so as to hold the ring firmly down, by means of nuts screwed upon them. The movable lid of the pump, which has the stuffing-box g formed in the centre of it, is screwed to the ring by five screws, and these can be taken out to remove the lid, and draw up the bucket, when it requires to be leathered.

F is the forcing pipe, formed of as many pieces of wooden pipes as are required to make up the length; they are united together by making the upper ends conical, to enter a similar cavity made in the lower end of the next pipe; the lowest piece fits upon the extremity of the projecting branch e, and a valve is proposed to be put in the pipe at this joint, to prevent the return of the water, and bear part of the weight of the column from the lowest valve at f; the upper end of the pipe has a spout i, at which the water is delivered.

Mis a second spout, fixed into the pipe lower than the former; it has a screw by which it can be united to a hole, or leather pipe, to convey the water to a distance, or by means of a jet, or branch-pipe, to throw it in the manner of a fire-engine; in this case the upper spout i must be stopped up, by a screw-plug or cap; and there is a copper air-tight vessel H, situated at the top of the pipe F, to equalize the pulsative motion of the water as thrown by the pump.

K is a bracket fixed to the pipe F, and projecting over the centre of the pump, where it has a hole to receive the pump rod h, and guide it steadily in its motion up and down, that it may not wear the stuffing-box away on one side. As the wooden tubes of which the forcing-pump F is composed inay be made from waste or crooked timber, it makes a great difference

between the low price of such, and that of the straight trees necessary for common pumps. A wooden plug may be chained to the pump, betwixt the spouts or nozles M and i, so as be ready to stop that which is not wanted in use.

Mr. Stephens is of opinion, that it is better to place the valve ƒ above the level of the water in the well.

8. Mr. William Tyror, of Liverpool, took out a patent in March, 1819, for certain improvements in the construction of pumps, and in the machinery for working the same.

This improvement consists in having four brass chambers, marked PPP, fig. 232, joined together by means of breech-pieces with screws, and soldered across the joints; these breech-pieces, marked Q, Q, being cast of brass, or any other suitable metal. When these are complete, PP, fig. 233, is placed upon the breech-piece Q7, fig. 234, and both of them are fixed to or under a box or frame suitable for the purpose.

This box or frame, fig. 238, is furnished with eight brass grooves, 000, fastened to the sides with screws; and a crank, or four cranks in one, that is, one crank out of each side of the same piece of square iron or any other suitable metal, one up, one down, one in front, and one in back. To one end of the crank, or cranks, is fixed two tooth and pinion wheels, a sufficient distance apart to allow two wheels of the same diameter and thickness to stand between them, so that the cranks may go round without moving the other wheels, marked C and E. The wheels D and F are made fast on the cranks A, A, by means of a screw or pin, and the wheels C and E, being fixed close together, slide to and fro upon the square end of the axle U, by means of the guide or sliding geer V, which is fixed in a groove turned out of the nave of the wheel C, by means of a clip and two screws which fasten it underneath, and rests in the notches fixed at the other end of the box or frame, for the end of the guide or geer to rest.

The notches are three in number on each side of the box or frame W. The one farthest from the wheel has the guide V, drawn back, with the wheel E upon the small wheel F. By moving the guide into the middle notch, the wheels C and E are kept between the wheels D and F; and the notch nearest the wheels guides the wheel C on the large wheel D, so that the power is much greater when forcing or drawing water from a great depth.

When the wheels C and E are placed in the space between the lower wheels, the handle is moved from the upper axle U, and placed upon the end of the crank A A, and the pump is worked without the assistance of the wheels as occasion may require. The machinery is furnished with four key-bow rods, marked B BB, for the purpose of fixing to them the spear boxes or plunging rods, by means of a joint and pin and bolt, the key-bow being filed square across in the inside, so as to give the roller-step a fair bearing.

Fig. 235 represents the rolling-step, which is formed of two pieces of brass, the one half round; of a thickness according to the strength or size of the machinery; and the other round, like a wheel or sheave in form, and of the same thickness as the other half. This round sheave or wheel is cut half through the middle edgeways, and the piece is then cut off, and a dovetail is cut down the width in proportion to the crank. The other half is then fitted into the place from whence the larger piece has been cut, and both of them are held together by means of two screws; and the sheave or wheel is then in the form of its appearance before it was cut. A hole is now drilled

through the centre, and it is fixed upon the before mentioned crank or cranks. Y, in fig. 236, represents the larger half of this step; and X, fig. 237, represents the smaller half, with the dove-tailed standing upon it, which fills up the vacancy or room that is made in the large half for fixing it upon the crank.

The ends of each key-bow is set in the grooves, OOO, fig. 238, and the keybow rods, B B B B, work through holes in the bottom of the box, for which purpose an iron-plate or base is formed with four holes, SSS, fig. 239, and is fixed at the bottom of the box or frame with screws. The rods, by being fitted into the holes in this plate, keep the stroke of the pump perpendicular, while the step rolls backwards and forwards in the key-bow, as they are forced up and down by the cranks moving or turning alternately round.

When this machinery is applied over a forcing-pump, or placed over a fire-engine, it causes a greater quantity of water to be discharged from the cistern or engine, and as it is very powerful, it is highly necessary that it should have a cock of a superior size, to let more water pass through in the same time than ordinary; for this purpose Mr. Tyror makes the barrel, or that part of the cock where the key or stop goes in on one side, so that there is but one stop to the plug or key, the stop, resting in that part that overhangs the side, admits of room for a full sized water-way to be com pletely through it, without causing the water to have any bubble or curl as it passes through the plug.

Reference to the figures:

Fig. 240 represents a side view of the cock.

Fig. 241, a top view of the same.

Fig. 242, the plug, with the water-way cut out.

Fig. 243 represents the crank, with the tooth and pinion wheels, and the rolling steps.

Fig. 244, the upper axle, with the improved plan of the sliding geer. Fig. 245, the spear box and rod in the form of the fastening at the top of the key-bow rod, when applied for shipping.

Fig. 246, a front view of the pump standing upon a ship's deck.

9. Mr. Richard Franklin has been rewarded by the Society of Arts for effecting certain improvements in the lifting and forcing pump, by which water can be conveyed into a cistern at the top of the house, to supply all the dressing-rooms, water-closets, &c.

A section of this pump is given in fig. 247.

AA are two pistons; on the upper face of each is a double valve, vvv vi the upper piston-rod passes through the stuffing-box B, and the lower through the stuffing-box C. S is the suction-pipe, and D the dischargingpipe.

Fig. 248 is an external view of the pump; eee the lever or handle; F the fulcrum, on which the handle moves; G G is the pump-cylinder; ww the wheels which revolve between the standards x x xx, and which conduct the piston-rods parallel to the cylinder; ep the conducting-rod, which conveys the motion of the handle to the lower piston; eo the conducting-rod, which gives motion to the upper piston. It is evident, when the handle or lever is lifted, that the upper piston is pressed down, and the lower piston is at the same time elevated, with its valves shut, which forces the water through the upper piston and the discharging-pipe at the same operation.