OF A NEW HAND-PUMP, INVENTED BY MR. WALTER TAYLOR, OF SOUTHAMPTON, AND USED BY THE ROYAL NAVY OF GREAT BRITAIN.

Every friend of mankind must rejoice on being informed, that the accidents to which thips that fpring a leak at fea were liable from the imperfections of the chain-pump, are happily removed by the ingenious contrivances of Mr. Walter Taylor, of Southampton, well known for his mechanical abilities; which in other inftances, as well as this, have proved equally beneficial to himfelf and his country. It feems rather furprizing that the common pump, whofe effects are fo well known, fhould have remained for centuries inadequate to the purposes of the navy. The mechanifm adapted by Mr. Taylor is fo important, and, in various particulars, fo different from what is in general applied to the common pump, that it may with great propriety be confidered as a new invention.

Mr. Taylor's pumps have been in general use in the royal navy for five or fix years: they have anfwered every expectation he first formed, though he has made many improvements on them during that period. Here are three figures, which will give you a general idea of thefe pumps; they were copied from drawings which were kindly communicated to me for this purpose by Mr. Taylor. Fig. 4, pl. 3, is a fection of one of Mr. Taylor's pumps, of a fimple conftruction. The pifton is reprefented as defcending in a chamber properly adapted thereto. At a and b you have a view of Mr. Taylor's pendulum valves; which, from their form, difengage themfelves from chips, gravel, fand, &c. The pifton is also so contrived,

that

that no chips, gravel, or fand, can get between the leather and lower part of the piston; to both which defects the former conftructions were liable. Fig. 7 is a feparate view of the pendulum valve.

Fig. 3 reprefents a pump working with one pifton-rod, and fig. 5 a pump working with two pifton-rods; the one rifing as the other falls: in fig. 4 and 5 the rods are fuppofed to be worked by levers. By a judicious application of ropes, to be carried on either deck, (fee fig. 6,) Mr. Taylor is enabled, where men are plenty, as in a man of war, to raise any quantity of water. The drawing is taken from a pump with a feven-inch bore, and heaves one ton per minute twenty-four feet high, with ten men, five only working at a time. One is now constructing by Mr. Taylor to heave five tons per minute twenty-four feet high. The pumps are alfo fo conftructed that a copper pump may be taken out of the wooden cafe, in order, when neceffity requires, to make two pumps for feparate work.

OF THE HESSIAN PUMP, fig. 7 and 8, pl. 2..

ABC, DE, two tin veffels, foldered together, but communicating with each other by a hole at bottom. The larger veffel is furnished with a rim, to receive the water thrown up by the circulating tubes, and convey it into the veffel DE. m, n, o, p, represent four tubes of metal, or glafs, open at both ends, but bent at top, and fixed in an angular pofition to the axis KL. When in their place, the extremity L of the axis refts upon a point at the bottom of the large veffel, while the upper part is fteadied, and kept in a vertical pofition, by paffing through a hole in a bar going over the large. veffel ABC.

Fill the veffels about two-thirds with water, and then make the tubes circulate rapidly by turning the handle S, and the rotatory centrifugal motion will raife the water, and discharge it into the fmall veffel DE, by the pipe h.

OF VERA'S PUMP, fig. 8, pl. 3; OR AN ENGINE TO RAISE WATER BY MEANS OF HAIR ROPES.

A and B are three hair ropes paffing over the pullies b and d, each of which has three grooves. The lower pulley, b, is immerfed in the water, and is kept therein by a weight fufpended from it. Thefe pullies are turned round with great rapidity by means of two multiplying wheels, one of which is feen at G. By turning the pullies, the cords revolve alfo with great rapidity, and the ascending fides carry up a confiderable quantity of water, which they discharge with violence into the refervoir H, from whence it is conveyed into any convenient place by the pipe K L. The ropes fhould not be more than an inch afunder.

There are two of thefe machines at Winds. The depth of the well where one of them is fixed is ninety-five feet, and the quantity of water, raifed by the utmost efforts of a man is about nine gallons per minute.

In the beginning of the motion, the column adhering to the rope is always lefs than when it has been worked for fome time, and continues to increase till the surrounding air partakes of it's motion.

OF A SUPPOSED IMPROVEMENT OF THE COMMON

PUMP.

In the year 1766 it was announced in the public papers, that at Seville, in Spain, a fimple fucking pump had been conftructed, which raised water fixty feet; and they concluded from thence, that those were ftrangely deceived who had afferted that the preffure of the atmosphere would not fupport a higher column than thirty-two feet. Ôn examination it was found, that an ignorant tinman at Seville had made a common fucking pipe with it's lower valve fixty feet from the furface of the water; but finding he could raife no water by it, either through impatience or paffion, with a ftroke of a hatchet he made a small opening about ten feet above the furface of the water, and which forced a fmall quantity of water above the lower valve; the reafon of which I fhall explain by a diagram.

Let PF, fig. 1, pl. 3, be the fucking tube, d the furface of the water, from d to F fixty feet; and that after a certain number of strokes of the piston the water was raised thirty-two feet in the tube, or to c; and that then a fmall hole was made at ten feet from the furface of the water. The air which enters this preffing equally every way, makes the water which is below b fall down into the well; while the preffure upwards forces the water up thirty-two feet, through the valve, into the body of the pump. But this is not all, for it would have carried it to a much greater height; for the air near the earth is above eight hundred times rarer, or lefs denfe, than water; and and fuppofing the denfity of a column thereof to be uniform (which is not the cafe), ten feet of water taken away would be equivalent to a

columin

column of eight thoufand feet of air; fo that the remaining twenty-two feet would be in equilibrium with the air, after being raised eight thousand feet. To have a fecond portion of water, the hole b must be stopped up, and the pifton worked till the water rifes to c, and then re-open the hole. In the first place you fee, that this pretended difcovery is fo far from invalidating the principle of the preffure of the air, that it is a direct confequence thereof; fecondly, that even to make it answer at all, it is neceffary that the pipe be very fmall, or the column of water would be broke to pieces, the air would pafs through, and very little would rife.

OF THE MOTION OF WATER IN CONDUIT-PIPES.

In conducting of water from one place to another, the conduit-pipes must be longer in proportion as the places to which it is to be conveyed are more diftant from each other. In the additional tubes heretofore fpoken of, I took no notice of friction, as in the cafes then under confideration it was fcarcely fenfible. In long tubes it is different; the friction of thefe leffens confiderably the velocity of the water.

On this head I can only relate to you the refult of various experiments that have been made; which it is impoffible for us to repeat, as they require not only a very large apparatus, but conveniences that are only to be procured by those whofe intereft is concerned in the experiments. The experiments of which I fhall give you the refults were made by Mr. Boffut; the tubes were ftrait; one of them was fixteen lines infide diameter, the other twq inches; and the tubes were fucceffively lengthened from thirty to an hundred and eighty feet. The conftant altitude of the water in the refervoir,