Pond, a small pool, or collection of standing water.

Ponds are of great utility in agriculture, and for various other purposes : hence different methods and expedients have been devised, with a view to obtain a constant supply of water: from these we have selected the following, which appear to merit particular attention.

In the first vol. of the Journal de Physique, we meet with an interesting method of making ponds water-tight, without the aid of masonry, by M. Dambourney.— He directs the pit to be dug to a convenient depth ; and its sides to be carefully sloped to an angle of about 40 degrees. The cement with which it is to be lined, should then be prepared in the following manner.

A sufficient quantity of brick-clay ought previously to be procured, in a moist state, so that it may be easily worked and incorporated with one-fourth part of quick-lime, slacked the preceding evening, in such a portion of water, as will reduce it to the consistence of cream-cheese; and the whole must be formed into balls, about two feet in circumference. When an adequate stock is collected, the workman descends into the cavity, and an assistant supplies him with a ball, which the former throws with all his strength on the ground, near the centre of the pit: thus, he continues the plastering with other balls, in such a direction that each may come in contact with the next following, till the sides and bottom of the intended pond are perfectly lined. If the whole cannot be finished in one day, the last row laid on in the evening should be moistened, in order that it may be sufficiently adhesive; to incorporate exactly with the new part of the work on the subsequent morning.—Two or three days after this composition is applied, it should be beaten with a flat piece of wood ; and, accordingly as its firmness increases, the beating must be stronger, and the surface occasionally wetted, to prevent cracks, till it become one uniform, solid piece. Lastly, the whole is to be covered with a coat of-any cheap oil ; and (previously to the admission of water), with gravel, to the thickness of one inch. By this management, the coating will acquire a very remarkable degree of firmness ; and, if the pond be constantly full, no repairs will become necessary; as the only injury to be apprehended, may proceed from intense frost, which is apt to damage such parts of the work as are exposed to the air.

In the sixth volume of Annals of Agriculture, an account is given of" a simple method of making artificiul ponds, in dry soils :—the subjoined cut represents an outline of their construction.

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The line A, describes a circular hole made in the ground, of such size as may be found necessary ; and on which a stratum of clay, B, must be carefully beaten, and trodden into a solid, compact body, from four to six inches in thickness.

C, represents a layer of quicklime about an inch, or an inch and a half thick ; and which should be uniformly spread over the whole.

D, is a second stratum of clay, that ought to be of a thickness similar to that above-mentioned, and should be pressed down in the same manner.

E, denotes stones, or gravel, either of which must be spread on the second layer of clay, to such depth as may prevent the pond from being injured by the feet of cattle ; for otherwise, they will penetrate the stratifications of clay and lime ; in consequence of which, the water will be discharged through the pores of the earth. When thus completed, according to the section above given, the pond will remain five feet deep, and forty-five in diameter; at which size these reservoirs are in general constructed ;-the letter F, representing the line of level, both of the water and of the ground.

This method of forming ponds was contrived in Yorkshire, about 25 or 30 years ago, by a well-sinker :—numerous artificial pools have since been made in that, as well as the adjoining counties. The expences attending a work of the

E dimensions above stated, are computed to be from 41. to 61. according to the distance from which the clay is carried. Such a pond will remain unimpaired for a series of years ; because the lime prevents worms from striking either upwards or downwards, and consequently from injuring the clay, which turally resists moisture.

Beside the utility of ponds, by affording a constant supply of water for various purposes, the Mud settling at the bottom furnishes an excellent manure. Hence it is a desirable object to draw off the fluid part, so as conveniently to arrive at the sediment: for this pur-, pose, a hole or pit should be dug in the centre of the pond, as far as the stratum of sand, which usually lies under that of clay. Thus, the water will be immediately absorbed, and the pond completely emptied :—the sides of the cavity, however, ought not to be made so steep as to prevent the return of cattle, in case they should enter it by accident.

In the 6th vol. of the Transactions of the Society for the Encouragement of Arts, etc. we-find a short account of a Machine for draining Ponds, without disturbing the mud. It was communicated by Lieutenant-Colonel Dan-sev, together with a drawing and model, of which we have given an engraving.

Fig. 1. A, is the pipe, loaded with a rim of lead, of such a weight as serves to sink it beneath the surface of the water.

B, represents the discharging pipe, that is laid through the bank H, I.

C, the joint on which the pipe A, turns ; and the form of which is delineated in Fig. 2.

D, the ball, or float, that swims on the surface of the pond, and thus prevents the pipe A from de-scending to a greater depth than the length of the chain, by which, they are connectted, will admit.

E, a chain that winds on the windlass F ; and serves to raise the tube A, above the surface of the water, when the machinery is not in use.

G, a stage.

H. I, the bank, which is represented as if it were cut through at I, in order to delineate the tube B, lying within it.

K. is a post designed for the reception of the pipe A, when the latter is lowered, and also for preventing it from sinking in the mud.

Fig. 1. A, is a cast cylinder, furnished with a brass plate or cheek, which is fastened to the timber of the tube, on one side only ; because the part of the cylinder C, turns in the hollow of the wooden tube, when it is immersed in the water. A piece of strong sole-leather is placed in the inside of such plate, to prevent leaking.

The model represented in our engraving, was constructed from the description of a machine employed by a gentleman residing in the vicinity of Taunton. In the year 1788, Colonel Dansey's regiment was quartered at Windsor; and, conceiving that the invention might be useful for the supply of the grand cascade at Virginia-Water, he presented the model before-mentioned to His Majesty, who graciously signified his approbation. In consequence of this event, a pen-stock was erected on the same plan, at one of the ponds in the vicinity.

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Colonel D. observes, in his communication to the Society, that he has often tried the model in a vessel of water and as the prin-ciple on which it is constructed, may be farther improved and extended, in the hands of ingenious men,we have furnished our readers with an accurate engraving :—this machine is applicable to silk, cotton, and other mills; where an uniform and steady velocity of water is required, which may at pleasure be regulated, without occasioning any current to disturb the fish, or mud ; because the stream constantly runs from the surface.

Pond-Water, to which cattle generally resort for drink, is a fluid strongly impregnated with saline and oily, particles ; hence it should never be suffered spontaneously to evaporate during the summer.

For the important purpose of Irrigation (which see), pond-water is in every respect equal to the liquor collected in farm-yards. See also Fluid Manures ; p. 161 of this volume.