Pump, a well-known hydraulic machine, employed for the raising of water by the pressure of the atmosphere.

The utility of pumps, in domestic life, being universally acknowledged, various contrivances have been proposed and adopted with a view to facilitate the drawing of water. Among the latest inventions, the American Pump Engine deserves particular notice. This machinery was contrived by Mr. Benjamin Dearborn, and is so constructed, that it may be conveniently added to a common pump, in order to answer the purposes of a Fire Engine.—We have, therefore, furnished our readers with a plate, from the Memoirs of the American Academy of Arts and Sciences, of which the following is an accurate description :

Fig. 1. A, B, C, D, represents a pump, the form of which is similar to that of the pumps commonly employed on ship-board.

E, the spout.

F, a stopper.

D. d, a plank-cap, that is fitted to the pump, and provided with leather on its lower surface; being secured by the screws a, b : in the centre is a hole, through which the spear of the pump passes, and round which a leather collar is made, as represented at the the letter c.

g, a nut for the screw .

f, a square piece of wood, that is nailed across one end of the plank-cap, through both which the screw a is introduced :—a hole is made through such piece and the cap, that communicates with the bore of the pump.

G, G, a wooden tube, which maybe of any requisite length, and consist of any number of joints : it is made square at the lower extremity, and perforated for the reception of the cock; the upper end being made with a nice shoulder.

e, a wooden cock, that opens or shuts the communication between the pump and the tube; being furnished on the opposite side with a handle and with a lock, in case it should be found necessary.

h, h, are two ferules, the object, of which is to prevent the tube from splitting:

If, H, braces each of which ought to be crossed over another, as nearly at right angles as possible.

i, i, are irons in the form of a staple, which surround the tube, and pass through the braces ; their ends being perforated with holes for fore-locks K, L, M, N, is a head, made of five pieces of wood ;—k, I, m, n, a square piece, in the lower part of which is a hole for the reception of the extremity of the tube, and which piece rests on the shoulder o, p;—to the lower end of this head is nailed a piece of leather, with a hole in its centra, similar to that made in the wood. Another piece of leather of the same form is placed on the top of the tube, and between both is a circle of thin plate-crass; the two pieces of leather and the brass being pressed between the lower end of the head, and the shoulder of the tube.— Their edges are delineated at o, p.

K, N, and L, M, are the edges of two pieces of plank, of a similar width with the head, to which they are closely nailed ; each being provided with a tennon, that passes through a mortice in the end of the piece O, P: both tenuous have holes for a forelock at q.

O, P, a piece of plank, of the same width as the sides ; the centre of which is perforated, in order that the tube may pass through; and in each end of which is a mortice for the reception of the tennons.

N, M, a cap.

r, r, are two pieces nailed to the side of the tube ; the lower extremity of each is provided with a truck, with a view to lessen the friction of the head in its horizontal revolution.

q, q, represent forelocks, the design of which is to fasten down the head, and prevent the water from escaping at the joint o, p.

Q, R, is a wooden conductor; the extremity marked with the letter Q, being solid, while the opposite end, R, is bored with a small auger.

S, A bolt, that passes through the conductor and head, being secured on the back with a fore-lock, or nut: this bolt is rounded near the head, and square in the middle.

t, u, w, x, represents a piece of iron or brass, designed to prevent the head of the bolt from wearing into the wood.

Pump 33

S, S, are ropes for the direction of the conductor.

Fig. 2. Represents the head without such conductor.

a, b, c, d, is a thick brass plate, the centre of which is perforated, so as to admit a passage to impurities, that might otherwise obstruct the conductor : for which purpose a piece of leather is nailed under it to the head. The square hole in the centre is adapted to the size of the bolt, which it prevents from turning. The conductor has a hollow cut round the bolt on the inside, of the same size as the circle of holes in the brass : round such cavity is nailed, on the face of the conductor, a piece of leather, that plays on the margin of the brass-plate, when the conductor is in motion.

In the conclusion of his Memoir, Mr. DearEorn observes, that he has raised a tube of 30 feet on his pump; and, though the severity of the season had prevented him from completing it, so that one person only could work at the brake ; yet he is enabled to throw water on a contiguous building, the nearest part of which is 37 feet from the pump, and between 30 and 40 feet in height

Numerous patents have been granted for inventions or improvements in the construction of pumps; of which the following deserve to be mentioned : namely, Mr. No-ble's, obtained in 1784; Mr. Skey's in 1785; Mr. Fulton's in 1788; and Mr. Buchanan's in 1796;— as, however, the specification of such patents, would occupy more room than our limits will permit, the curious reader will consult the earlier vols, of the Repertory of Art , etc.; where they are detailed, and illustrated with engravings.