LARCH TUBES.

Fig. 14.Wedge-Drain.Fig. 15.Shoulder-Drain.

Fig. 14.Wedge-Drain.

Fig. 15.Shoulder-Drain.

These drains may be formed in almost any kind of land which is not a loose gravel or sand. They are a very cheap kind of drain; for neither the cost of cutting nor filling in, much exceeds that of the ordinary tile drain, while the expense of tiles or other materials is altogether saved. Still, such drains cannot be recommended, for they are very liable to injury, and, even under the most favorable circumstances, can only last a very limited time.

These have been used in Scotland, in mossy or swampy soils, it is said, with economy and good results. The tuberepresented below presents a square of 4 inches outside, with a clear water-way of 2 inches. Any other durable wood will, of course, answer the same purpose. The tube is pierced with holes to admit the water. In wet meadows, these tubes laid deep would be durable and efficient, and far more reliable than brush or even stones, because they may be better protected from the admission of sand and the ruinous working of vermin. Their economy depends upon the price of the wood and the cost of tiles—which are far better if they can be reasonably obtained.

Fig. 16.—Larch Tube-Drain.

Near Washington, D. C., we know of drainage tolerably well performed by the use of common fence-rails. A trench is opened about three inches wider at bottom than two rails. Two rails are then laid in the bottom, leaving a space of two or three inches between them. A third rail is then laid on for a cover, and the whole carefully covered with turf or straw, and then filled up with earth. Poles of any kind may be used instead of rails, if more convenient.

In clay, these drains would be efficient and durable; in sand, they would be likely to be filled up and become useless. This is an extravagant waste of timber, except in the new districts where it is of no value.

Mr. J. F. Anderson, of Windham, Maine, has adopted a mode of draining with poles, which, in regions where wood is cheap and tiles are dear, may be adopted with advantage.

Two poles, of from 3 to 6 inches diameter, are laid at the bottom of the ditch, with a water-way of half their diameter between them. Upon these, a third pole is laid,thus forming a duct of the desired dimensions. The security of this drain will depend upon the care with which it is protected by a covering of turf and the like, to prevent the admission of earth, and its permanency will depend much upon its being placed low enough to be constantly wet, as such materials are short-lived when frequently wet and dried, and nearly imperishable if constantly wet. It is unnecessary to place brush or stones over such drains to make them draw, as it is called. The water will find admission fast enough to destroy the work, unless great care is used.

Fig. 17.—Pole-Drain.

In Ireland, and in some parts of England and Scotland, peat-tiles are sometimes used in draining bogs. They are cheap and very durable in such localities, but, probably, will not be used in this country. They are formed somewhat like pipes, of two pieces of peat. Two halves are formed with a peculiar tool, with a half circle in each. When well dried, they are placed together, thus making a round opening.

Fig. 18.—Tool for Peat-Tiles.

Fig. 19.—Peat-Tiles.

In draining, the object being merely to form a durableopening in the soil, at suitable depth, which will receive and conduct away the water which filters through the soil, it is obvious that a thousand expedients may be resorted to, to suit the peculiar circumstances of persons. In general, the danger to be apprehended is from obstruction of the water-way. Nothing, except a tight tube of metal or wood, will be likely to prevent the admission of water.

Economy and durability are, perhaps, the main considerations. Tiles, at fair prices, combine these qualities better than anything else. Stones, however, are both cheap and durable, so far as the material is concerned; but the durability of the material, and the durability of the drains, are quite different matters.

Providence has so liberally supplied the greater part of New England with stones, that it seems to most inexperienced persons to be a work of supererogation, almost, to manufacture tiles or any other draining material for our farms.

We would by no means discourage the use of stones, where tiles cannot be used with greater economy. Stone drains are, doubtless, as efficient as any, so long as the water-way can be kept open. The material is often close at hand, lying on the field and to be removed as a nuisance, if not used in drainage. In such cases, true economy may dictate the use of them, even where tiles can be procured; though, we believe, tiles will be found generally cheaper, all things considered, where made in the neighborhood.

In treating of the cost of drainage, we have undertaken to give fair estimates of the comparative cost of different materials.

Every farmer is capable of making estimates for himself,and of testing those made by us, and so of determining what is true economy in his particular case.

The various modes of constructing drains of stones, may be readily shown by simple illustrations:

Fig. 20.Fig. 21.

Fig. 20.

Fig. 21.

Fig. 22.Fig. 23.

Fig. 22.

Fig. 23.

If stone-drains are decided upon, the mode of constructing them will depend upon the kind of stone at hand. In some localities, round pebble-stones are found scattered over the surface, or piled in heaps upon our farms; in others, flat, slaty stones abound, and in others, broken stones from quarries may be more convenient. Of these, probably,the least reliable is the drain filled with pebble-stones, or broken stones of small size. They are peculiarly liable to be obstructed, because there is no regular water-way, and the flow of the water must, of course, be very slow, impeded as it is by friction at all points with the irregular surfaces.

Sand, and other obstructing substances, which find their way, more or less, into all drains, are deposited among the stones—the water having no force of current sufficient to carry them forward—and the drain is soon filled up at some point, and ruined.

Miles of such drains have been laid on many New England farms, at shoal depths, of two or two and a half feet, and have in a few years failed. For a time, their effect, to those unaccustomed to under-drainage, seems almost miraculous. The wet field becomes dry, the wild grass gives place to clover and herds-grass, and the experiment is pronounced successful. After a few years, however, the wild grass re-appears, the water again stands on the surface, and it is ascertained, on examination, that the drain is in some place packed solid with earth, and is filled with stagnant water.

The fault is by no means wholly in the material. In clay or hard pan, such a drain may be made durable, with proper care, but it must be laid deep enough to be beyond the effect of the treading of cattle and of loaded teams, and the common action of frost. They can hardly be laid low enough to be beyond the reach of our great enemy, the mole, which follows relentlessly all our operations.

We recollect the remarks of Mr. Downing about the complaints in New England, of injury to fruit-trees by the gnawing of field-mice.

He said he should as soon think of danger from injury by giraffes as field-mice, in his own neighborhood, though he had no doubt of their depredations elsewhere!

It may seem to many, that we lay too much stress onthis point, of danger from moles and mice. We know whereof we do testify in this matter. We verily believe that we never finished a drain of brush or stones, on our farm, ten rods long, that there was not a colony of thesevarmintin the one end of it, before we had finished the other. If these drains, however, are made three or four feet deep, and the solid earth rammed hard over the turf, which covers the stones, they will be comparatively safe.

The figures 24 and 25 below, represent a mode of laying stone drains, practiced in Ireland, which will be found probably more convenient and secure than any other method, for common small drains. A flat stone is set upright against one side of the ditch, which should be near the bottom, perpendicular. Another stone is set leaning against the first, with its foot resting against the opposite bank. If the soil be soft clay, a flat stone may be placed first on the bottom of the ditch, for the water to flow upon; but this will be found a great addition to the labor, unless flat stones of peculiarly uniform shape and thickness are at hand. A board laid at the bottom will be usually far cheaper, and less liable to cause obstructions.

Figs. 24, 25.—Stone Drains.

Figure25represents the ditch without the small stonesabove the duct. These small stones are, in nine cases in ten, worse than useless, for they are not only unnecessary to admit the water, but furnish a harbor for mice and other vermin.

Drawings, representing a filling of small stones above the duct, have been copied from one work to another for generations, and it seems never to have occurred, even to modern writers, that the small stones might be omitted. Any one, who knows anything of the present system of draining with tiles, must perceive at once that, if we have the open triangular duct or the square culvert, the water cannot be kept from finding it, by any filling over it with such earth as is usually found in ditching. Formerly, when tiles were used, the ditch was filled above the tiles, to the height of a foot or more, with broken stones; but this practice has been everywhere abandoned as expensive and useless.

An opening of any form, equal to a circle of two or three inches diameter, will be sufficient in most cases, though the necessary size of the duct must, of course, depend on the quantity of water which may be expected to flow in it at the time of the greatest flood.

Whatever the form of the stone drain, care should be taken to make the joints as close as possible, and turf, shavings, straw, tan, or some other material, should be carefully placed over the joints, to prevent the washing in of sand, which is the worst enemy of all drains.

It is not deemed necessary to remark particularly upon the mode of laying large drains for water-courses, with abutments and covering stones, forming a square duct, because it is the mode universally known and practiced. For small drains, in thorough-draining lands, it may, however, be remarked, that this is, perhaps, the most expensive of all modes, because a much greater width of excavation is necessary in order to place in position the twoside stones and leave the requisite space between them. That mode of drainage which requires the least excavation and the least carriage of materials, and consequently the least filling up and levelling, is usually the cheapest.

Our conclusion as to stone drains is, that, at present, they may be, in many cases, found useful and economical; and even where tiles are to be procured at present prices stones may well be used, where materials are at hand, for the largest drains.

What are Drain-Tiles?—Forms of Tiles.—Pipes.—Horse-shoe Tiles.—Sole-Tiles—Form of Water-Passage.—Collars and their Use.—Size of Pipes.—Velocity.—Friction.—Discharge of Water through Pipes.—Tables of Capacity.—How Water enters Tiles.—Deep Drains run soonest and longest.—Pressure of Water on Pipes.—Durability of Tile Drains.—Drain-Bricks 100 years old.

This would be an absurd question to place at the head of a division in a work intended for the English public, for tiles are as common in England as bricks, and their forms and uses as familiar to all. But in America, though tiles are used to a considerable extent in some localities, probably not one farmer in one hundred in the whole country ever saw one.

The author has recently received letters of inquiry about the use and cost of tiles, from which it is manifest that the writers have in their mind as tiles, the square bricks with which our grandfathers used to lay their hearths.

In Johnstone'sReport to the Board of Agriculture on Elkington's System of Draining, published in England in 1797, the only kind of tiles or clay conduits described or alluded to by him, are what he calls "draining-bricks," of which he gives drawings, which we transfer to our pages precisely as found in the American edition. It will beseen to be as clumsy a contrivance as could well be devised.

Fig. 26.—Draining-Bricks.

So lately as 1856, tiles were brought from Albany, N. Y., to Exeter, N. H., nearly 300 miles, by railway, at a cost, including freight, of $25 a thousand for two-inch pipes, and it is believed that no tiles were ever made in New Hampshire till the year 1857. These facts will soon become curiosities in agricultural literature, and so are worth preserving. They furnish excuse, too, for what may appear to learned agriculturists an unnecessary particularity in what might seem the well-known facts relative to tile-drainage.

Drain-tiles are made of clay of almost any quality that will make bricks, moulded by a machine into tubes, or into half-tube or horse-shoe forms, usually fourteen inches long before drying, and burnt in a furnace or kiln to be about as hard as what are called hard-burnt bricks. They are usually moulded about half an inch in thickness, varying with the size and form of the tile. The sizes vary from one inch to six inches, and sometimes larger, in the diameter of the bore. The forms are also very various; and as this is one of the most essential matters,as affecting the efficiency, the cost, and the durability of tile-drainage, it will be well to give it critical attention.

The simplest, cheapest, and best form of drain-tile is the cylinder, or merely a tube, round outside and with a round bore.

Figs. 27, 28, 29.—Round Pipes.

Tiles of this form, and all others which are tubular, are calledpipes, in distinction from those with open bottoms, like those of horse-shoe form.

About forty years ago, as Mr. Gisborne informs us, small pipes for land-drainage were used, concurrently, by persons residing in the counties of Lincoln, Oxford, and Kent, who had, probably, no knowledge of each other's operations. Most of those pipes were made with eyelet-holes, to admit the water. Pipes for thorough-draining excited no general attention till they were exhibited by John Read at the show at Derby, in the year 1843. A medal was awarded to the exhibitor. Mr. Parkes was one of the judges, and brought the pipes to the special notice of the council. From this time, inventions and improvements were rapid, and soon, collars were introduced, and the use of improved machines to mould the pipes;and drainage, under the fostering influence of the Royal Agricultural Society, became a subject of general attention throughout the kingdom. The round pipe, orthe pipe, as it seems,par excellence, to be termed by English drainers, though one of the latest, if not the last form of tiles introduced in England, has become altogether the most popular among scientific men, and is generally used in all works conducted under the charge of the Land Drainage Companies. This ought to settle the question for us, when we consider that the immense sum of twenty millions of dollars of public funds has been expended by them, in addition to vast amounts of private funds, and that the highest practical talent of the nation is engaged in the work.

After giving some idea of the various forms of tiles in use, it is, however, proposed to examine the question upon its merits, so that each may judge for himself which is best.

The earliest form of tiles introduced for the purpose of thorough-drainage, was the horse-shoe tile, so called from its shape. The horse-shoe tile has been sometimes used without any sole to form the bottom of the drain, thus leaving the water to run on the ground. There can hardly be a question of the false economy of this mode, for the hardest and most impervious soil softens under the constant action of running water, and then the edges of the tiles must sink, or the bottom of the drain rise, and thus destroy the work.

Various devices have been tried to save the expense of soles, such as providing the edges of the tiles with flanges or using pieces of soles on which to rest the ends of the tiles. They all leave the bottom of the drain unprotected against the wearing action of the water.

Horse-shoe tiles, or "tops and bottoms" as they are called in some counties, are still much used in England;and in personal conversation with farmers there, the writer found a strong opinion expressed in their favor. The advantages claimed for the "tops and bottoms" are, that they lie firmly in place, and that they admit the water more freely than others.

The objections to them are, that they are more expensive than round pipes, and are not so strong, and are not so easily laid, and that they do not discharge water so well as tiles with a round bore. In laying them, they should be made to rest partly upon two adjoining soles, or to break bond, as it is called. The soles are made separate from the tiles, and are merely flat pieces, of sufficient width to support firmly both edges of the tiles. The soles are usually an inch wider than the tiles.

Fig. 30—Horse-shoe Tiles and Soles.

The above figure represents the horse-shoe tiles and soles properly placed.

As this form of tile has been generally used by the most successful drainers in New York, it may be well to cite the high authority of Mr. Gisborne for the objections which have been suggested. It should be recollected in this connection, that the drainage in this country has been what in England would be called shallow, and that it is too recent to have borne the test of time.

Mr. Gisborne says:

"We shall shock and surprise many of our readers, when we state confidently that, in average soils, and still more in those which are inclined to be tender, horse-shoe tiles form the weakest and most failing conduit which has ever been used for a deep drain. It is so, however; and a little thought, even if we had no experience, will tell us that it must be so."A horse-shoe tile, which may be a tolerably secure conduit in a drain of 2 feet, in one of 4 feet becomes an almost certain failure. Asto the longitudinal fracture, not only is the tile subject to be broken by one of those slips which are so troublesome in deep draining, and to which the lightly-filled material, even when the drain is completed, offers an imperfect resistance, but the constant pressure together of the sides, even when it does not produce a fracture of the soil, catches hold of the feet of the tile, and breaks it through the crown. When the Regent's Park was first drained, large conduits were in fashion, and they were made circular by placing one horse-shoe tile upon another. It would be difficult to invent a weaker conduit. On re-drainage, innumerable instances were found in which the upper tile was broken through the crown and had dropped into the lower."

"A horse-shoe tile, which may be a tolerably secure conduit in a drain of 2 feet, in one of 4 feet becomes an almost certain failure. Asto the longitudinal fracture, not only is the tile subject to be broken by one of those slips which are so troublesome in deep draining, and to which the lightly-filled material, even when the drain is completed, offers an imperfect resistance, but the constant pressure together of the sides, even when it does not produce a fracture of the soil, catches hold of the feet of the tile, and breaks it through the crown. When the Regent's Park was first drained, large conduits were in fashion, and they were made circular by placing one horse-shoe tile upon another. It would be difficult to invent a weaker conduit. On re-drainage, innumerable instances were found in which the upper tile was broken through the crown and had dropped into the lower."

Another form of tiles, calledsole-tiles, orsole-pipes, is much used in America, more indeed than any other, except perhaps the horse-shoe tile; probably, because the first manufacturers fancied them the best, and offered no others in the market.

In this form, the sole is solid with the tile. The bottom is flat, but the bore is round, or oval, or egg-shaped, with the small end of the orifice downward.

Fig. 31—Sole-Tile.

The sole-pipe has considerable advantages theoretically. The opening or bore is of the right shape, the bottom lies fair and firm in place, and the drain, indeed, is perfect, if carefully and properly laid.

The objections to the sole-pipes are, that they are somewhat more expensive than round pipes, and that they require great care in placing them, so as to make the passage even from one pipe to another.

A slight depression of one side of a pipe of this kind, especially if the bore be oval or egg-shaped, throws the water passage out of line. In laying them, the author has taken the precaution to place under each joint a thin piece of wood, such as our honest shoe manufacturers use forstiffening in shoes, to keep the bottoms of the pipes even, at least until the ground has settled compactly, and as much longer as they may escape "decay's effacing finger."

Collarsfor tiles are used wherever a sudden descent occurs in the course of a drain, or where there is a loose sand or a boggy place, and by many persons they are used in all drains through sandy or gravelly land.

Fig. 32.—Pipes and Collar.

The above figure represents pipe-tiles fitted with collars. Collars are merely short sections of pipes of such size as to fit upon the smaller ones loosely, covering the joint, and holding the ends in place, so that they cannot slip past each other. In very bad places, small pipes may be entirely sheathed in larger ones; and this is advisable in steep descents or flowing sands.

A great advantage in round pipes is, that there is no wrong-side-up to them, and they are, therefore, more readily placed in position than tiles of any other form.

Again: all tiles are more or less warped in drying and burning; and, where it is desired to make perfect work, round pipes may be turned so as to make better joints and a straighter run for the water—which is very important.

If collars are used, there is still less difficulty in adjusting the pipes so as to make the lines straight, and far less danger of obstruction by sand or roots. Indeed, it is believed that no drain can be made more perfect than with round pipes and collars.

As it is believed that few collars have ever yet been used in this country, and the best drainers in England are not agreed as to the necessity of using them, we give the opinions of two or three distinguished gentlemen, in their own language. Mr. Gisborne says:

"We were astounded to find, at the conclusion of Mr. Parkes' NewcastleLecture, this sentence: 'It may be advisable for me to say, that in clays, and other clean-cutting and firm-bottomed soils, I do not find the collars to be indispensably necessary, although I always prefer their use.' This is a barefaced treachery to pipes, an abandonment of the strongest point in their case—the assured continuity of the conduit. Every one may see how very small a disturbance at their point of junction would dissociate two pipes of one inch diameter. One finds a soft place in the bottom of the drain and dips his nose into it one inch deep, and cocks up his other end. By this simple operation, the continuity of the conduit is twice broken. An inch of lateral motion produces the same effect. Pipes of a larger diameter than two inches are generally laid without collars. This is a practice on which we do not look with much complacency; it is the compromise between cost and security, to which the affairs of men are so often compelled. No doubt, a conduit from three to six inches in diameter is much less subject to a breach in its continuity than one which is smaller; but, when no collars are used, the pipes should be laid with extreme care, and the bed which is prepared for them at the bottom of the drain should be worked to their size and shape with great accuracy."To one advantage which is derived from the use of collars we have not yet adverted—the increased facility with which free water existing in the soil can find entrance into the conduit."The collar for a one and a half inch pipe has a circumference of nine inches. The whole space between the collar and the pipe, on each side of the collar, is open, and affords no resistance to the entrance of water: while, at the same time, the superincumbent arch of the collar protects the junction of two pipes from the intrusion of particles of soil. We confess to some original misgivings, that a pipe resting only on an inch at each end, and lying hollow, might prove weak, and liable to fracture by weight pressing on it from above; but the fear was illusory. Small particles of soil trickle down the sides of every drain, and the first flow of water will deposit them in the vacant space between the two collars. The bottom, if at all soft, will also swell up into any vacancy. Practically, if you re-open a drain well laid with pipes and collars, you will find them reposing in a beautiful nidus, which, when they are carefully removed, looks exactly as if it had been moulded for them."

"To one advantage which is derived from the use of collars we have not yet adverted—the increased facility with which free water existing in the soil can find entrance into the conduit.

"The collar for a one and a half inch pipe has a circumference of nine inches. The whole space between the collar and the pipe, on each side of the collar, is open, and affords no resistance to the entrance of water: while, at the same time, the superincumbent arch of the collar protects the junction of two pipes from the intrusion of particles of soil. We confess to some original misgivings, that a pipe resting only on an inch at each end, and lying hollow, might prove weak, and liable to fracture by weight pressing on it from above; but the fear was illusory. Small particles of soil trickle down the sides of every drain, and the first flow of water will deposit them in the vacant space between the two collars. The bottom, if at all soft, will also swell up into any vacancy. Practically, if you re-open a drain well laid with pipes and collars, you will find them reposing in a beautiful nidus, which, when they are carefully removed, looks exactly as if it had been moulded for them."

As to the danger of breaking the pipes, which might well be apprehended, we found by actual experiment, at the New York Central Park, that a one-inch Albany piperesting on collars upon a floor, with a bearing at each end of but one inch, would support the weight of a man weighing 160 pounds, standing on one foot on the middle of the pipe.

Mr. Parkes sums up his opinion upon the subject of collars, in these words:

"It may be advisable for me to say, that in clays, and other clean-cutting and firm-bottomed soils, I do not find collars to be at all necessary; but that they are essential in all sandy, loose, and soft strata."

In draining in the neighborhood of trees, collars are also supposed to be of great use in preventing the intrusion of roots into the pipes, although it may be impossible, even in this way, to exclude the roots of water-loving trees.

From the most careful inquiry that the writer was able to make, as to the practice in England, he is satisfied that collars are not generally used there in the drainage of clays, but that the pipes are laid in openings shaped for them at the bottom of the drains, with a tool which forms a groove into which the pipes fall readily into line, and very little seems to be said of collars in the published estimates of the cost of drainage.

On this subject, we have the opinion of Mr. Denton, thus expressed:

"The use of collars is by no means general, although those who have used them speak highly of their advantages. Except in sandy soils, and in those that are subject to sudden alteration of character, in some of the deposits of red sand-stones, and in the clayey subsoils of the Bagshot sand district, for instance, collars are not found to be essential to good drainage. In the north of England they are used but seldom, and, in my opinion, much less than they ought to be; but this opinion, it is right to state, is opposed, in numerous instances of successful drainage, by men of extensive practice; and as every cause of increased outlay is to be avoided, the value of collars, as general appliances, remains an open question. In all the more porous subsoils in which collars have not been used, the more successful drainers increase the size of the pipes in the minor drains to a minimum size of two inches bore."

The form of the bore, or water passage, in tiles, is a point of more importance than at first appears. At one of our colleges, certain plank sewers, in the ordinary square form, were often obstructed by the sediment from the dirty water. "Turn them cornerwise," suggested the professor of Natural Philosophy. It was done, and ever after they kept in order. The pressure of water depends on its height, or head. Everybody knows that six feet of water carries a mill-wheel better than one foot. The same principle operates on a small scale. An inch head of water presses harder than a half inch. Thevelocityof water, again, depends much on its height. Whether there be much or little water passing through a drain, it has manifestly a greater power to make its way, to drive before it sand or other obstructions, when it is heaped up in a round passage, than when wandering over the flat surface of a tile sole. Any one who has observed the discharge of water from flat-bottomed and round tiles, will be satisfied that the quantity of water which is sufficient to run in a rapid stream of a half or quarter inch diameter from a round tile, will lazily creep along the flat bottom of a sole tile, with hardly force sufficient to turn aside a grain of sand, or to bring back to light an enterprising cricket that may have entered on an exploration. On the whole, solid tiles, with flat-bottomed passages, may be set down among the inventions of the adversary. They have not the claims even of the horse-shoe form to respect, because they do not admit water better than round pipes, and are not united by a sole on which the ends of the adjoining tiles rest. They combine the faults of all other forms, with the peculiar virtues of none.

Fig. 33—Flat-bottomed Pipe-Tile.

From an English report on the drainage of towns, the following, which illustrates this point, is taken:

"It was found that a large proportion of sewers were constructed with flat bottoms, which, when there was a small discharge, spread the water, increased the friction, retarded the flow, and accumulated deposit. It was ascertained, that by the substitution of circular sewers of the same width, with the same inclination and the same run of water, the amount of deposit was reduced more than one-half."

Is a matter of much importance, whether we regard the efficiency and durability of our work, or economy in completing it. The cost of tiles, and the freight of them, increase rapidly with their size, and it is, therefore, well to use the smallest that will effect the object in view. Tiles should be large enough, as a first proposition, to carry off, in a reasonable time, all the surplus water that may fall upon the land. Here, the English rules will not be safe for us; for, although England has many more rainy days than we have, yet we have, in general, a greater fall of rain—more inches of water from the clouds in the year. Instead of their eternal drizzle, we have thunder showers in Summer, and in Spring and Autumn north-east storms, when the windows of heaven are opened, and a deluge, except in duration, bursts upon us. Then, at the North, the Winter snows cover the fields until April, when they suddenly dissolve, often under heavy showers of rain, and planting time is at once upon us. It is desirable that all the snow and rain-water should pass through the soil into the drains, instead of overflowing the surface, so as to save the elements of fertility with which such water abounds, and also to prevent the washing of the soil. We require, then, a greater capacity of drainage, larger tiles, than do the English, for our drains must do a greater work than theirs, and in less time.

There are several other general considerations that should be noticed, before we attempt to define the particular size for any location. Several small drains are usually discharged into one main drain. This main should have sufficient capacity to conduct all the water that may be expected to enter it, and no more. If the small drains overflow it, the main will be liable to be burst, or the land about it filled with water, gushing from it at the joints; especially, if the small drains come down a hill side, so as to give a great pressure, or head of water. On the other hand, if the main be larger than is necessary, there is the useless expense of larger tiles than were required. The capacity of pipes to convey water, depends, other things being equal, upon their size; but here the word size has a meaning which should be kept clearly in mind.

The capacity of round water-pipes is in proportion to the squares of their diameters.

A one-inch pipe carries one inch (circular, not square) of water, but a two-inch pipe carries not two inches only, but twice two, or four inches of water; a three-inch pipe carries three times three, or nine inches; and a four-inch pipe, sixteen inches. Thus we see, that under the same conditions as to fall, directness, smoothness, and the like, a four-inch pipe carries just four times as much water as a two-inch pipe. In fact, it will carry more than this proportion, becausefriction, which is an important element in all such calculations, is greater in proportion to the smaller size of the pipe.

Velocityis another essential element to be noticed in determining the amount of water which may be discharged through a pipe of given diameter. Velocity, again, depends on several conditions. Water runs faster down a steep hill than down a gentle declivity. This is due to the weight of the water, or, in other words, to gravitation, and operates whether the water be at large onthe ground, or confined in a pipe, and it operates alike whether the water in a pipe fill its bore or not.

But, again, the velocity of water in a pipe depends on the pressure, or head of water, behind it, and there is, perhaps, no definite limit to the quantity of water that may be forced through a given orifice. More water, for instance, is often forced through the pipe of a fire-engine in full play, in ten minutes, than would run through a pipe of the same diameter, lying nearly level in the ground, in ten hours.

In ordinary aqueducts, for supplying water, and not for drainage, it is desirable to have a high pressure upon the pipes to ensure a rapid flow; but in drainage, a careful distinction must be made between velocity induced by gravitation, and velocity induced by pressure. If induced by the former merely, the pipe through which the water is swiftly running, if not quite full, may still receive water at every joint, while, if the velocity be induced by pressure, the pipe must be already full. It can then receive no more, and must lose water at the joints, and wet the land through which it passes, instead of draining it.

So that although we should find that the mains might carry a vast quantity of water admitted by minor drains from high elevations, yet we should bear in mind, that drains when full can perform no ordinary office of drainage. If there is more than the pressure of four feet head of water behind; the pipes, if they passed through a pond of water, at four feet deep, must lose and not receive water at the joints.

The capacity of a pipe to convey water depends, then, not only on its size, but on its inclination or fall—a pipe running down a considerable descent having much greater capacity than one of the same size lying nearly level. This fact should be borne in mind even in laying single drains; for it is obvious that if the drain lie along a sandyplain, for instance, extending down a springy hill-side, and then, as is usually the case, along a lower plain again, to its outlet at some stream, it may collect as much water as will fill it before it reaches the lower level. Its stream rushes swiftly down the descent, and when it reaches the plain, there is not sufficient fall to carry it away by its natural gravitation. It will still rush onward to its outlet, urged by the pressure from behind; but, with such pressure, it will, as we have seen, instead of draining the land, suffuse it with water.

as has already been suggested, is an element that much interferes with exact calculations as to the relative capacity of water-pipes of various dimensions, and this depends upon several circumstances, such as smoothness, and exactness of form, and directness. The smoother, the more regular in form, and the straighter the drain, the more water will it convey. Thus, in some recent English experiments,

"it was found that, with pipes of the same diameter, exactitude of form was of more importance than smoothness of surface; that glass pipes, which had a wavy surface, discharged less water, at the same inclinations, than Staffordshire stone-ware clay pipes, which were of perfectly exact construction. By passing pipes of the same clay—the common red clay—under a second pressure, obtained by a machine at an extra expense of about eighteen pence per thousand, whilst the pipe was half dry, very superior exactitude of form was obtained, and by means of this exactitude, and with nearly the same diameters, an increased discharge of water of one-fourth was effected within the same time."

So all sudden turns or angles increase friction and retard velocity, and thus lessen the capacity of the drain—a topic which may be more properly considered under the head of the junction of drains.

"On a large scale, it was found that when equal quantities of water were running direct, at a rate of 90 seconds, with a turn at right-angles,the discharge was only effected in 140 seconds; whilst, with a turn or junction with a gentle curve, the discharge was effected in 100 seconds."

We are indebted to Messrs. Shedd & Edson for the following valuable tables showing the capacity of water-pipes, with the accompanying suggestions:

"DISCHARGE OF WATER THROUGH PIPES."The following tables of discharge are founded on the experiments made by Mr. Smeaton, and have been compared with those by Henry Law, and with the rules of Weisbach and D'Aubuisson. The conditions under which such experiments are made may be so essentially different in each case, that few experiments give results coincident with each other, or with the deductions of theory: and in applying these tables to practice, it is quite likely that the discharge of a pipe of a certain area, at a certain inclination, may be quite unlike the discharge found to be due to those conditions by this table, and that difference may be owing partly to greater or less roughness on the inside of the pipe, unequal flow of water through the joints into the pipe, crookedness of the pipes, want of accuracy in their being placed, so that the fall may not be uniform throughout, or the ends of the pipes may be shoved a little to one side, so that the continuity of the channel is partially broken; and, indeed, from various other causes, all of which may occur in any practical case, unless great care is taken to avoid it, and some of which may occur in almost any case."We have endeavored to so construct the tables that, in the ordinary practice of draining, the discharge given may approximate to the truth for a well laid drain, subject even to considerable friction. The experiments of Mr. Smeaton, which we have adopted as the basis of these tables, gave a less quantity discharged, under certain conditions, than given under similar conditions by other tables. This result is probably due to a greater amount of friction in the pipes used by Smeaton. The curves of friction resemble, very nearly, parabolic curves, but are not quite so sharp near the origin."We propose, during the coming season, to institute some careful experiments, to ascertain the friction due to our own drain-pipe. Water can get into the drain-pipe very freely at the joints, as may be seen by a simple calculation. It is impossible to place the ends so closely together, in laying, as to make a tight joint on account of roughness in the clay, twisting in burning, &c.; and the opening thus made will usually average about one-tenth of an inch on the whole circumference,which is, on the inside of a two-inch pipe, six inches—making six-tenths of a square inch opening for the entrance of water at each joint."In a lateral drain 200 feet long, the pipes being thirteen inches long, there will be 184 joints, each joint having an opening of six-tenth square inch area; in 184 joints there is an aggregate area of 110 square inches; the area of the opening at the end of a two-inch pipe is about three inches; 110 square inches inlet to three inches outlet; thirty-seven times as much water can flow in as can flow out. There is, then, no need for the water to go through the pores of the pipe; and the fact is, we think, quite fortunate, for the passage of water through the pores would in no case be sufficient to benefit the land to much extent. We tried an experiment, by stopping one end of an ordinary drain-pipe and filling it with water. At the end of sixty-five hours, water still stood in the pipe three-fourths of an inch deep. About half the water first put into the pipe had run out at the end of twenty-four hours. If the pipe was stopped at both ends and plunged four feet deep in water, it would undoubtedly fill in a short time; but such a test is an unfair one, for no drain could be doing service, over which water could collect to the depth of four feet."

"The following tables of discharge are founded on the experiments made by Mr. Smeaton, and have been compared with those by Henry Law, and with the rules of Weisbach and D'Aubuisson. The conditions under which such experiments are made may be so essentially different in each case, that few experiments give results coincident with each other, or with the deductions of theory: and in applying these tables to practice, it is quite likely that the discharge of a pipe of a certain area, at a certain inclination, may be quite unlike the discharge found to be due to those conditions by this table, and that difference may be owing partly to greater or less roughness on the inside of the pipe, unequal flow of water through the joints into the pipe, crookedness of the pipes, want of accuracy in their being placed, so that the fall may not be uniform throughout, or the ends of the pipes may be shoved a little to one side, so that the continuity of the channel is partially broken; and, indeed, from various other causes, all of which may occur in any practical case, unless great care is taken to avoid it, and some of which may occur in almost any case.

"We have endeavored to so construct the tables that, in the ordinary practice of draining, the discharge given may approximate to the truth for a well laid drain, subject even to considerable friction. The experiments of Mr. Smeaton, which we have adopted as the basis of these tables, gave a less quantity discharged, under certain conditions, than given under similar conditions by other tables. This result is probably due to a greater amount of friction in the pipes used by Smeaton. The curves of friction resemble, very nearly, parabolic curves, but are not quite so sharp near the origin.

"We propose, during the coming season, to institute some careful experiments, to ascertain the friction due to our own drain-pipe. Water can get into the drain-pipe very freely at the joints, as may be seen by a simple calculation. It is impossible to place the ends so closely together, in laying, as to make a tight joint on account of roughness in the clay, twisting in burning, &c.; and the opening thus made will usually average about one-tenth of an inch on the whole circumference,which is, on the inside of a two-inch pipe, six inches—making six-tenths of a square inch opening for the entrance of water at each joint.

"In a lateral drain 200 feet long, the pipes being thirteen inches long, there will be 184 joints, each joint having an opening of six-tenth square inch area; in 184 joints there is an aggregate area of 110 square inches; the area of the opening at the end of a two-inch pipe is about three inches; 110 square inches inlet to three inches outlet; thirty-seven times as much water can flow in as can flow out. There is, then, no need for the water to go through the pores of the pipe; and the fact is, we think, quite fortunate, for the passage of water through the pores would in no case be sufficient to benefit the land to much extent. We tried an experiment, by stopping one end of an ordinary drain-pipe and filling it with water. At the end of sixty-five hours, water still stood in the pipe three-fourths of an inch deep. About half the water first put into the pipe had run out at the end of twenty-four hours. If the pipe was stopped at both ends and plunged four feet deep in water, it would undoubtedly fill in a short time; but such a test is an unfair one, for no drain could be doing service, over which water could collect to the depth of four feet."

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