Of the depth, direction, and distance of drains, our views will be found under the appropriate heads. They apply alike to open and covered drains.
Having a farm destitute of stones, before tiles were known among us, we made several experiments with covered drains filled with brush. Some of those drains operated well for eight or ten years; others caved in and became useless in three or four years, according to the condition of the soil.
In a wet swamp a brush drain endures much longer than in sandy land, which is dry a part of the year, because the brush decays in dry land, but will prove nearly imperishable in land constantly wet. In a peat or muck swamp, we should expect that such drains, if carefully constructed, might last twenty years, but that in a sandy loam they would be quite unreliable for a single year.
Our failure on upland with brush drains, has resulted, not from the decay of the wood, but from the entrance of sand, which obstructed the channel. Moles and field-mice find these drains the very day they are laid, and occupy them as permanent homes ever after.
Those little animals live partly upon earth-worms, which they find by burrowing after them in the ground, and partly upon insects, and vegetation above ground. They have a great deal of business, which requires convenient passages leading from their burrows to the day-light, and drains in which they live will always be found perforated with holes from the surface. In the Spring, or in heavy showers, the water runs in streams into these holes, breaks down the soft soil as it goes, and finally the top begins to fall in, and the channel is choked up, and the work ruined. We have tried many precautions against this kind of accident, but none that was effectual on light land.
The general mode of construction is this: Open the trench to the depth required, and about 12 inches wide at the bottom. Lay into this poles of four or five inches diameter at the butt, leaving an open passage between. Then lay in brush of any size, the coarsest at the bottom, filling the drain to within a foot of the surface, and covering with pine, or hemlock, or spruce boughs. Upon these lay turf, carefully cut, as close as possible. The brush should be laid but-end up stream, as it obstructs the water less in this way. Fill up with soil a foot above the surface, and tread it in as hard as possible. The weight of earth will compress the brush, and the surface will settle very much. We have tried placing boards at the sides, and upon the top of the brash, to prevent the caving in, but with no great success. Although our drains thus laid, have generally continued to discharge some water, yet they have, upon upland, been dangerous traps and pitfalls for our horses and cattle, and have cost much labor to fill up the holes, where they have fallen through by washing away below.
In clay, brush drains might be more durable. In the English books, we have descriptions of drains filled with thorn cuttings from hedges and with gorse. When well laid in clay, they are said to last about 15 years. When the thorns decay, the clay will still retain its form, and leave a passage for the water.
A writer in the Cyclopedia sums up the matter as to this kind of drains, thus:
"Although in some districts they are still employed, they can only be looked upon as a clumsy, and superficial plan of doing that which can be executed in a permanent and satisfactory manner, at a very small additional expense, now that draining-tiles are so cheap and plentiful."
Draining-tiles are not yet either cheap or plentiful in this country; but we have full faith that they will become so very soon. In the mean time it may be profitable for us to use such of the substitutes for them as may lie within our reach, selecting one or another according as material is convenient.
has never been, that we are aware, practiced in America. Our knowledge of it is limited to what we learn from English books. We, therefore, content ourselves with giving from Morton's Cyclopedia the following description and illustrations.
"Plug-draining, like mole-draining, does not require the use of any foreign material—the channel for the water being wholly formed of clay, to which this kind of drain, like that last mentioned is alone suited.
"This method of draining requires a particular set of tools for its execution, consisting of, first, a common spade, by means of which the first spit is removed, and laid on one side; second, a smaller-sized spade, by means of which the second spit is taken out, and laid on the opposite side of the trench thus formed; third, a peculiar instrument called a bitting iron (Fig. 11), consisting of a narrow spade, three and a half feet in length, and one and a half inches wide at the mouth and sharpened like a chisel; the mouth, or blade, being half an inch in thickness in order to give the necessary strength to so slender an implement. From the mouth, a, on the right-hand side, a ring of steel, b, six inches long and two and a half broad, projects at right angles; and on the left, at fourteen inches from the mouth, a tread, c, three inches long, is fitted.
"A number of blocks of wood, each one foot long, six inches high, and two inches thick at the bottom, and two and a half at the top, are next required. From four to six of these are joined together by pieces of hoop-iron let into their sides by a saw-draught, a small space being left between their ends, so that when completed, the whole forms a somewhat flexible bar, as shown in the cut, to one end of which a stout chain is attached. These blocks are wetted, and placed with the narrow end undermost, in the bottom of the trench, which should be cut so as to fit them closely; the clay which has been dug out is then to be returned, by degrees, upon the blocks, and rammed down with a wooden rammer three inches wide. As soon as the portion of the trench above the blocks, or plugs, has been filled, they are drawn forward, by means of a lever thrust through a link of the chain, and into the bottom of the drain for a fulcrum, until they are all again exposed, except the last one. The further portion of the trench, above the blocks, is now filled in and rammed, and so on the operations proceed until the whole drain is finished."
We hear of an implement, in use in Illinois and other Western States, called the Gopher Plow, worked by a capstan, which drains wet land by merely drawing through it an iron shoe, at about two and a half feet in depth, without the use of any foreign substance.
We hear reports of a mole plow, in use in the same State, known by the name of Marcus and Emerson's Patent Subsoiler, with which, an informant says, drains are made also in the manner above named. This machine is worked by a windlass power, by a horse or yoke of oxen, and the price charged is twenty-eight cents a rod for the work. These machines are, from description, modifications of the English Mole Plow, an implement long ago known and used in Great Britain.
The following description is from Morton's Cyclopedia:
"Mole-Drains are the simplest of all the forms of the covered drains. They are formed by means of a machine called the mole plow. This machine consists of a long wooden beam and stilts, somewhat in the form of the subsoil plow; but instead of the apparatus for breaking up the subsoil in the latter, a short cylindrical and pointed bar of iron is attached, horizontally, to the lower end of the broad coulter, which can be raised or lowered by means of a slot in the beam. The beam itself is sheathed with iron on the under side, and moves close to the ground; thus keeping the bar at the end of the coulter at one uniform depth. This machine is dragged through the soft clay, which is the only kind of land on which it can be used with propriety, by means of a chain and capstan, worked by horses, and produces a hollow channel very similar to a mole-run, from which it derives its name."
A correspondent of the New York Tribune thus describes the operation and utility of a mole plow, which he saw on the farm of Major A. B. Dickinson, of Hornby, Steuben County, New York:
"I believe there is not a rod of tile laid on this farm, and not a dozen rods of covered stone drain. But the major has a home-made, or, at least, home-devised, 'bull plow,' consisting of a sharp-pointed iron wedge, or roller, surmounted by a broad, sharp shank nearly four feet high, with a still sharper cutter in front, and with a beam and handles above all. With five yoke of oxen attached, this plow is put down through the soil and subsoil to an average depth of three feet—in the course which the superfluous water is expected and desired to take—and the field thus plowed through and through, at intervals of two rods, down to three feet, as the ground is more or less springy and saturated with water. The cut made by the shank closes after the plow and is soon obliterated, while that made by the roller, or wedge, at the bottom, becomes the channel of a stream of water whenever there is any excess of moisture above its level, which stream tends to clear itself and rather enlarge its channel. From ten to twenty acres a day are thus drained, and Major D. has such drains of fifteen to twenty years' standing, which still do good service. In rocky soils, this mode of draining is impracticable: in sandy tracts it would not endure; but here it does very well, and, even though it should hold good in the average but ten years, it would many times repay its cost."
Major Dickinson himself in a recent address, thus speaks of what he calls his
"I will take the poorest acre of stubble ground, and if too wet for corn in the first place, I will thoroughly drain it with a Shanghae plow and four yoke of oxen in three hours.
"I will suppose the acre to be twenty rods long and eight rods wide. To thoroughly drain the worst of your clay subsoil, it may require a drain once in eight feet, and they can be made so cheaply that I can afford to make them at that distance. To do so, will require the team to travel sixteen times over the twenty rods lengthwise, or one mile in three hours; two men to drive, one to hold the plow, one to ride the beam, and one to carry the crow-bar, pick up any large stones thrown out by going to the right or left, and to help to carry around the plow, which is too heavy for the other two to do quickly.
"The plow is quite simple in its construction, consisting of a round piece of iron three and a half or four inches in diameter, drawn down to a point, with a furrow cut in the top one and a half inches deep; a plate, eighteen inches wide and three feet long, with one end welded into the furrow of the round bar, while the other is fastened to the beam. The coulter is six inches in width, and is fastened to the beam at one end, and at the other to the point of the round bar. The coulter and plate are each three-fourths of an inch thick, which is the entire width of the plow above the round iron at the bottom.
"It would require much more team to draw this plow on some soils than on yours. The strength of team depends entirely on the character of the subsoil. Cast-iron, with the exception of the coulter, for an easy soil would be equally good; and from eighteen to twenty-four inches is sufficiently deep to run the plow. I can as thoroughly drain an acre of ground in this way as any that can be found in Seneca County."
From the best information we can gather, it would seem, that on certain soils with a clay subsoil, the mole plow, as a sort of pioneer implement, may be very useful. The above account certainly indicates that on the farm in question it is very cheap, rapid, and effectual in its operation.
Stephens gives a minute description of the mole plow figured above, in his Book of the Farm. Its general structure and principle of operation may be easily understood by what has been already said, and any person desirous of constructing one may find in that work exact directions.
WEDGE AND SHOULDER DRAINS.
These, like the last-mentioned kind of drains, are mere channels formed in the subsoil. They have, therefore, the same fault of want of durability, and are totally unfitted for land under the plow. In forming wedge-drains, the first spit, with the turf attached, is laid on one side, and the earth removed from the remainder of the trench is laid on the other. The last spade used is very narrow, and tapers rapidly, so as to form a narrow wedge-shaped cavity for the bottom of the trench. The turf first removed is then cut into a wedge, so much larger than the size of the lower part of the drain, that when rammed into it with the grassy side undermost, it leaves a vacant space in the bottom six or eight inches in depth, as in Fig. 14.
The shoulder-drain does not differ very materially from the wedge-drain. Instead of the whole trench forming a gradually tapering wedge, the upper portion of the shoulder-drain has the sides of the trench nearly perpendicular, and of considerable width, the last spit only being taken out with a narrow, tapering spade, by which means a shoulder is left on either side, from which it takes its name. After the trench has been finished, the first spit, having the grassy side undermost as in the former case, is placed in the trench, and pushed down till it rests upon the shoulders already mentioned; so that a narrow wedge-shaped channel is again left for the water, as shown in Fig. 15.
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 tube represented 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.
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.
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.
In draining, the object being merely to form a durable opening 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.
DRAINS OF STONES.
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:
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 on this 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 these varmint in 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.
Figure 25 represents the ditch without the small stones above 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 two side 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.
DRAINAGE WITH TILES.
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.
WHAT ARE DRAIN-TILES?
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's Report 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 be seen to be as clumsy a contrivance as could well be devised.
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 FORMS OF TILES.
The simplest, cheapest, and best form of drain-tile is the cylinder, or merely a tube, round outside and with a round bore.
Tiles of this form, and all others which are tubular, are called pipes, 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, or the 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.
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. As to 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, called sole-tiles, or sole-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.
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 for stiffening 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."
COLLARS for 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.
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' Newcastle Lecture, 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."
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 pipe resting 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. The velocity of 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.
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."
THE SIZE OF TILES.
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, because friction, which is an important element in all such calculations, is greater in proportion to the smaller size of the pipe.
VELOCITY is 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 on the 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 sandy plain, 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."
1-1/2-INCH DRAIN-PIPE. Area: 1.76709 inches. ==================================================================== FALL VELOCITY DISCHARGE FALL VELOCITY DISCHARGE in per second in gallons in per second in gallons 100 feet. in feet. in 24 hours. 100 feet. in feet. in 24 hours. -+ + + -+ + ft. in. ft. in. 0.3 0.71 5630.87 5.3 3.75 29704.51 0.6 1.04 8248.03 5.6 3.84 30454.28 0.9 1.29 10230.73 5.9 3.93 31168.06 1.0 1.52 12054.81 6.0 4.00 31723.21 1.3 1.74 13799.59 6.3 4.10 32516.36 1.6 1.91 15147.83 6.6 4.18 33150.76 1.9 2.10 16654.68 6.9 4.25 33705.91 2.0 2.26 17923.61 7.0 4.33 34340.38 2.3 2.41 19113.23 7.3 4.41 34974.85 2.6 2.56 20302.86 7.6 4.49 35609.30 2.9 2.69 21333.86 7.9 4.56 36154.45 3.0 2.83 22444.17 8.0 4.65 36878.23 3.3 2.94 23150.71 8.3 4.71 37354.08 3.6 3.06 24268.25 8.6 4.79 37988.55 3.9 3.16 25061.34 8.9 4.85 38464.40 4.0 3.28 26013.03 9.0 4.91 38940.25 4.3 3.38 26806.11 9.3 4.98 39495.39 4.6 3.46 27440.58 9.6 5.04 39971.24 4.9 3.56 28233.66 9.9 5.10 40447.10 5.0 3.65 28947.43 10.0 5.16 40922.93 ====================================================================
==================================================================== 2-INCH DRAIN-PIPE. 3-INCH DRAIN-PIPE. - - FALL VELOCITY DISCHARGE FALL VELOCITY DISCHARGE in per second in gallons in per second in gallons 100 feet. in feet. in 24 hours. 100 feet. in feet. in 24 hours. - - ft. in. ft. in. 0.3 0.79 10575.4 0.3 0.90 24687.2 0.6 1.16 15528.4 0.6 1.33 36482.2 0.9 1.50 20079.9 0.9 1.66 45534.2 1.0 1.71 22891.1 1.0 1.94 53214.7 1.3 1.94 25970.0 1.3 2.19 60072.2 1.6 2.16 28915.1 1.6 2.43 66655.5 1.9 2.35 31458.5 1.9 2.63 72141.5 2.0 2.53 33868.1 2.0 2.83 77627.6 2.3 2.69 36009.9 2.3 3.00 82290.7 2.6 2.83 37884.0 2.6 3.16 86679.6 2.9 2.97 39758.2 2.9 3.31 90794.1 3.0 3.11 41632.4 3.0 3.47 95182.9 3.3 3.24 43372.6 3.3 3.60 98748.9 3.6 3.36 44979.0 3.6 3.74 102589.1 3.9 3.48 46585.4 3.9 3.87 106155.0 4.0 3.59 48057.9 4.0 3.99 109446.7 4.3 3.70 49530.5 4.3 4.11 112738.3 4.6 3.80 50869.1 4.6 4.23 116029.9 4.9 3.91 52341.6 4.9 4.34 119047.3 5.0 4.02 53814.1 5.0 4.46 122338.9 5.3 4.11 55018.9 5.3 4.57 125356.2 5.6 4.22 56491.5 5.6 4.68 128373.5 5.9 4.31 57696.3 5.9 4.78 131116.6 6.0 4.40 58901.1 6.0 4.89 134133.9 6.3 4.49 60105.9 6.3 4.98 136602.6 6.6 4.58 61309.7 6.6 5.08 139345.6 6.9 4.66 62381.6 6.9 5.18 142088.7 7.0 4.74 63452.5 7.0 5.27 144557.4 7.3 4.83 64667.3 7.3 5.37 147306.4 7.6 4.91 65728.3 7.6 5.46 150069.1 7.9 4.99 66799.2 7.9 5.55 152237.8 8.0 5.07 67870.1 8.0 5.64 154706.6 8.3 5.15 68941.0 8.3 5.73 157175.3 8.6 5.23 70011.9 8.6 5.82 159644.0 8.9 5.31 71082.8 8.9 5.91 162112.7 9.0 5.38 72019.9 9.0 5.99 164313.2 9.3 5.46 73090.9 9.3 6.07 166501.6 9.6 5.53 74027.9 9.6 6.16 168970.3 9.9 5.60 74965.0 9.9 6.24 171164.7 10.0 5.67 75902.0 10.0 6.32 173359.1 ====================================================================
==================================================================== 4-INCH DRAIN-PIPE. 5-INCH DRAIN-PIPE. - - FALL VELOCITY DISCHARGE FALL VELOCITY DISCHARGE in per second in gallons in per second in gallons 100 feet. in feet. in 24 hours. 100 feet. in feet. in 24 hours. - - ft. in. ft. in. 0.3 1.08 43697.6 0.3 1.13 99584.2 0.6 1.50 60691.2 0.6 1.57 138362.4 0.9 1.83 74043.2 0.9 1.90 167442.6 1.0 2.13 86181.4 1.0 2.20 193881.0 1.3 2.38 96296.6 1.3 2.45 215912.9 1.6 2.61 105602.6 1.6 2.70 237944.9 1.9 2.81 113694.8 1.9 2.90 255569.5 2.0 3.00 121382.3 2.0 3.10 273195.9 2.3 3.19 129089.9 2.3 3.29 289940.1 2.6 3.36 135948.2 2.6 3.46 304921.9 2.9 3.53 142826.5 2.9 3.64 320784.9 3.0 3.68 148895.7 3.0 3.80 334885.4 3.3 3.82 154560.2 3.3 3.96 348974.8 3.6 3.96 160224.7 3.6 4.11 362204.9 3.9 4.10 165889.2 3.9 4.26 375424.1 4.0 4.24 171553.7 4.0 4.40 387762.1 4.3 4.37 176813.6 4.3 4.52 398337.5 4.6 4.50 182073.5 4.6 4.66 410675.3 4.9 4.62 186928.3 4.9 4.78 421250.6 5.0 4.75 192188.7 5.0 4.90 430825.0 5.3 4.86 196639.4 5.3 5.02 442401.3 5.6 4.97 201090.1 5.6 5.14 452976.6 5.9 5.09 205945.3 5.9 5.25 462670.6 6.0 5.20 210396.0 6.0 5.37 473246.0 6.3 5.30 214442.1 6.3 5.49 483820.4 6.6 5.41 218892.8 6.6 5.60 493514.6 6.9 5.51 222938.8 6.9 5.70 502327.4 7.0 5.61 226984.9 7.0 5.80 511140.2 7.3 5.71 231031.0 7.3 5.90 520052.0 7.6 5.81 235077.1 7.6 6.00 528766.5 7.9 5.91 239123.2 7.9 6.10 537578.7 8.0 6.01 243169.2 8.0 6.20 546391.5 8.3 6.10 246810.7 8.3 6.30 555204.5 8.6 6.19 250452.2 8.6 6.40 564017.0 8.9 6.28 255493.7 8.9 6.49 571948.0 9.0 6.37 257735.2 9.0 6.58 579880.0 9.3 6.45 260971.9 9.3 6.66 586930.2 9.6 6.54 264603.1 9.6 6.75 594861.4 9.9 6.63 268254.9 9.9 6.84 602793.2 10.0 6.71 271491.8 10.0 6.93 610723.8 ====================================================================
8-INCH DRAIN-PIPE. Area: 50.2640 inches. ==================================================================== FALL VELOCITY DISCHARGE FALL VELOCITY DISCHARGE in per second in gallons in per second in gallons 100 feet. in feet. in 24 hours. 100 feet. in feet. in 24 hours. -+ + + -+ + ft. in. ft. in. 0.3 1.23 277487.7 5.3 5.35 1206959.3 0.6 1.65 372239.7 5.6 5.47 1234031.3 0.9 2.01 453455.7 5.9 5.59 1261103.3 1.0 2.33 525647.7 6.0 5.71 1288175.3 1.3 2.60 586559.7 6.3 5.83 1315247.3 1.6 2.85 642959.6 6.6 5.95 1343838.9 1.9 3.08 694847.6 6.9 6.07 1369391.3 2.0 3.30 744479.7 7.0 6.17 1391951.2 2.3 3.50 789599.6 7.3 6.27 1414531.1 2.6 3.70 844719.7 7.6 6.39 1441583.2 2.9 3.89 877583.5 7.9 6.50 1466399.3 3.0 4.05 913679.5 8.0 6.60 1488959.2 3.3 4.21 949775.6 8.3 6.70 1511539.1 3.6 4.37 971658.7 8.6 6.80 1534099.0 3.9 4.53 920447.4 8.9 6.90 1556658.9 4.0 4.67 1055551.4 9.0 7.00 1579199.3 4.3 4.81 1086135.4 9.3 7.10 1601759.2 4.6 4.95 1116718.7 9.6 7.20 1624319.1 4.9 5.08 1146047.4 9.9 7.29 1644622.1 5.0 5.22 1177631.3 10.0 7.38 1664927.1 ====================================================================
HOW WATER ENTERS THE TILES.
How water enters the tiles, is a question which all persons unaccustomed to the operation of tile-draining usually ask at the outset. In brief, it may be answered, that it enters both at the joints and through the pores of the burnt clay, but mostly at the joints.
Mr. Parkes expresses the opinion, based upon careful observation, that five hundred times as much water enters at the crevices as through the pores of the tiles! If this be so, we may as well, for all practical purposes, regard the water as all entering at the joints. In several experiments which we have attempted, we have found the quantity of water that enters through the pores to be quite too small to be of much practical account.
Tiles differ so much in porosity, that it is difficult to make experiments that can be satisfactory—soft-burnt tiles being, like pale bricks, quite pervious, and hard-burnt tiles being nearly or quite impervious. The amount of pressure upon the clay in moulding also affects the density and porosity of tiles.
Water should enter at the bottom of the tiles, and not at the top. It is a well-known fact in draining, that the deepest drain flows first and longest. A familiar illustration will make this point evident. If a cask or deep box be filled with sand, with one hole near the bottom and another half way to the top, these holes will represent the tiles in a drain. If water be poured into the sand, it will pass downward to the bottom of the vessel, and will not flow out of either hole till the sand be saturated up to the lower hole, and then it will flow out there. If, now, water be poured in faster than the lower hole can discharge it, the vessel will be filled higher, till it will run out at both holes. It is manifest, however, that it will first cease to flow from the upper orifice. There is in the soil a line of water, called the "water-line," or "water-table;" and this, in drained land, is at about the level of the bottom of the tiles. As the rain falls it descends, as in the vessel; and as the water rises, it enters the tiles at the bottom, and never at the top, unless there is more than can pass out of the soil by the lower openings (the crevices and pores) into the tiles. It is well always to interrupt the direct descent of water by percolation from the surface to the top of the tiles, because, in passing so short a distance in the soil, the water is not sufficiently filtered, especially in soil so recently disturbed, but is likely to carry with it not only valuable elements of fertility, but also particles of sand, which may obstruct the drain. This is prevented by placing above the tiles (after they are covered a few inches with gravel, sand, or other porous soil) compact clay, if convenient. If not, a furrow each side of the drain, or a heaping-up of the soil over the drain, when finished, will turn aside the surface-water, and prevent such injury.
In the estimates as to the area of the openings between pipes, it should be considered that the spaces between the pipes are not, in fact, clean openings of one-tenth of an inch, but are partially closed by earthy particles, and that water enters them by no means as rapidly as it would enter the clean pipes before they are covered. Although the rain-fall in England is much less in quantity and much more regular than in this country, yet it is believed that the use of two-inch pipes will be found abundantly sufficient for the admission and conveyance of any quantity of water that it may be necessary to carry off by drainage in common soils. In extraordinary cases, as where the land drained is a swamp, or reservoir for water which falls on the hills around, larger pipes must be used.
In many places in England "tops and bottoms," or horse-shoe tiles, are still preferred by farmers, upon the idea that they admit the water more readily; but their use is continued only by those who have never made trial of pipes. No scientific drainer uses any but pipes in England, and the million of acres well drained with them, is pretty good evidence of their sufficiency. In this country, horse-shoe tiles have been much used in Western New York, and have been found to answer a good purpose; and so it may be said of the sole-pipes. Indeed, it is believed that no instance is to be found on record in America of the failure of tile drains, from the inability of the water to gain admission at the joints.
It may be interesting in this connection to state, that water is 815 times heavier than air. Here is a drain at four feet depth in the ground, filled only with air, and open at the end so that the air can go out. Above this open space is four feet of earth saturated with water. What is the pressure of the water upon the tiles?
Mr. Thomas Arkell, in a communication to the Society of Arts, in England, says—
"The pressure due to a head of water four or five feet, may be imagined from the force with which water will come through the crevices of a hatch with that depth of water above it. Now, there is the same pressure of water to enter the vacuum in the pipe-drain as there is against the hatches, supposing the land to be full of water to the surface."
It is difficult to demonstrate the truth of this theory; but the same opinion has been expressed to the writer by persons of learning and of practical skill, based upon observations as to the entrance of water into gas pipes, from which it is almost, if not quite, impossible to exclude it by the most perfect joints in iron pipes. Whatever be the theory as to pressure, or the difficulties as to the water percolating through compact soils to the tiles, there will be no doubt left on the mind of any one, after one experiment tried in the field, that, in common cases, all the surplus water that reaches the tiles is freely admitted. A gentleman, who has commenced draining his farm, recently, in New Hampshire, expressed to the author his opinion, that tiles in his land admitted the water as freely as a hole of a similar size to the bore of the tile would admit it, if it could be kept open through the soil without the tile.
DURABILITY OF TILE DRAINS.
How long will they last? This is the first and most important question. Men, who have commenced with open ditches, and, having become disgusted with the deformity, the inconvenience, and the inefficiency of them, have then tried bushes, and boards, and turf, and found them, too, perishable; and again have used stones, and after a time seen them fail, through obstructions caused by moles or frost—these men have the right to a well-considered answer to this question.
The foolish fellow in the Greek Reader, who, having heard that a crow would live a hundred years, purchased one to verify the saying, probably did not live long enough to ascertain that it was true. How long a properly laid tile-drain of hard-burnt tiles will endure, has not been definitely ascertained, but it is believed that it will outlast the life of him who lays it.
No tiles have been long enough laid in the United States to test this question by experience, and in England no further result seems to have been arrived at, than that the work is a permanent improvement.
In another part of this treatise, may be found some account of Land Drainage Companies, and of Government loans in aid of improvements by drainage in Great Britain. One of these acts provides for a charge on the land for such improvements, to be paid in full in fifty years. That is to say, the expense of the drainage is an incumbrance like a mortgage on the land, at a certain rate of interest, and the tenant or occupant of the land, each year pays the interest and enough more to discharge the debt in just fifty years. Thus, it is assumed by the Government, that the improvement will last fifty years in its full operation, because the last year of the fifty pays precisely the same as every other year.
It may therefore be considered as the settled conviction of all branches of the British government, and of all the best-informed, practical land-drainers in that country, that TILE-DRAINAGE WILL ENDURE FIFTY YEARS AT LEAST, if properly executed.
This is long enough to satisfy any American; for the migratory habits of our citizens, and the constant changes of cultivated fields into village and city lots, prevent our imagination even conceiving the idea that we or our posterity can remain for half a century upon the same farm.
It is much easier, however, to lay tile-drains so that they will not be of use half of fifty years, than to make them permanent in their effect. Tile-drainage, it cannot be too much enforced, is an operation requiring great care and considerable skill—altogether more care and skill than our common laborers, or even most of our farmers, are accustomed to exercise in their farm operations.
A blunder in draining, like the blunder of a physician, may be soon concealed by the grass that grows over it, but can never be corrected. Drainage is a new art in this country, and tile-making is a new art. Without good, hard-burnt tiles, no care or skill can make permanent work.
Tile-drainage will endure so long as the tiles last, if the work be properly done.
There is no reason why a tile should not last in the ground as long as a brick will last. Bricks will fall to pieces in the ground in a very short time if not hard-burnt, while hard-burnt bricks of good clay will last as long as granite.
Tiles must be hard-burnt in order to endure. But this is not all. Drains fail from various other causes than the crumbling of the tiles. They are frequently obstructed by mice, moles, frogs, and vermin of all kinds, if not protected at the outlet. They are often destroyed by the treading of cattle, and by the deposit of mud at the outlet, through insufficient care. They are liable to be filled with sand, through want of care in protecting the joints in laying, and through want of collars, and other means of keeping them in line. They are liable, too, to fill up by deposits of sand and the like, by being laid lower in some places than the parts nearer the outlet, so that the slack places catch and retain whatever is brought down, till the pipe is filled.
FROST is an enemy which in this country we have to contend with, more than in any other, where tile-drainage has been much practiced.
Upon all these points, remarks will be found under the appropriate heads; and these suggestions are repeated here, because we know that haste and want of skill are likely to do much injury to the cause which we advocate. Any work that requires only energy and progress, is safe in American hands; but cautious and slow operations are by no means to their taste.
Dickens says, that on railways and coaches, wherever in England they say, "All right," the Americans use, instead, the phrase, "Go ahead." In tile-drainage, the motto, "All right," will be found far more safe than the motto, "Go ahead."
Instances are given in England of drains laid with handmade tiles, which have operated well for thirty years, and have not yet failed.
Mr. Parkes informs us: "That, about 1804, pipe-tiles made tapering, with one end entering the other, and two inches in the smallest point, were laid down in the park now possessed by Sir Thomas Whichcote, Aswarby, Lincolnshire, and that they still act well."
Stephens gives the following instance of the durability of bricks used in draining:
"Of the durability of common brick, when used in drains, there is a remarkable instance mentioned by Mr. George Guthrie, factor to the Earl of Stair or Calhoun, Wigtonshire. In the execution of modern draining on that estate, some brick-drains, on being intersected, emitted water very freely. According to documents which refer to these drains, it appears that they had been formed by the celebrated Marshal, Earl Stair, upwards of a hundred years ago. They were found between the vegetable mould and the clay upon which it rested, between the 'wet and the dry,' as the country phrase has it, and about thirty-one inches below the surface. They presented two forms—one consisting of two bricks set asunder on edge, and the other two laid lengthways across them, leaving between them an opening of four inches square for water, but having no soles. The bricks had not sunk in the least through the sandy clay bottom upon which they rested, as they were three inches broad. The other form was of two bricks laid side by side, as a sole, with two others built or laid on each other, at both sides, upon the solid ground, and covered with flat stones, the building being packed on each side of the drain with broken bricks."
In our chapter upon the "Obstruction of Drains," the various causes which operate against the permanency of drains, are more fully considered.
DIRECTION, DISTANCE, AND DEPTH OF DRAINS.
DIRECTION OF DRAINS.—Whence comes the Water?—Inclination of Strata.—Drains across the Slope let Water out as well as Receive it.—Defence against Water from Higher Land.—Open Ditches.—Headers.—Silt-basins.
DISTANCE OF DRAINS.—Depends on Soil, Depth, Climate, Prices, System.—Conclusions as to Distance.
DEPTH OF DRAINS.—Greatly Increases Cost.—Shallow Drains first tried in England.—10,000 Miles of Shallow Drains laid in Scotland by way of Education.—Drains must be below Subsoil plow, and Frost.—Effect of Frost on Tiles and Aqueducts.
DIRECTION OF DRAINS.
Whether drains should run up and down the slope of the hill, or directly across it, or in a diagonal line as a compromise between the first two, are questions which beginners in the art and mystery of drainage usually discuss with great zeal. It seems so plain to one man, at the first glance, that, in order to catch the water that is running down under the soil upon the subsoil, from the top of the hill to the bottom, you must cut a ditch across the current, that he sees no occasion to examine the question farther. Another, whose idea is, to catch the water in his drain before it rises to the surface, as it is passing up from below or running along on the subsoil, and keep it from rising higher than the bottom of his ditch, thinks it quite as obvious that the drains should run up and down the slope, that the water, once entering, may remain in the drain, going directly down hill to the outlet. A third hits on the Keythorpe system, and regarding the water as flowing down the slope, under the soil, in certain natural channels in the subsoil, fancies they may best be cut off by drains, in the nature of mains, running diagonally across the slope.
These different ideas of men, if examined, will be found to result mainly from their different notions of the underground circulation of water. In considering the Theory of Moisture, an attempt was made to suggest the different causes of the wetness of land.
To drain land effectually, we must have a correct idea of the sources of the water that makes the particular field too wet; whether it falls from the clouds directly upon it; or whether it falls on land situated above it and sloping towards it, so that the water runs down, as upon a roof, from other fields or slopes to our own; or whether it gushes up in springs which find vent in particular spots, and so is diffused through the soil.
If we have only to take care of the water that falls on our own field, from the clouds, that is quite a different matter from draining the whole adjoining region, and requires a different mode of operation. If your field is in the middle, or at the foot, of an undrained slope, from which the water runs on the surface over your land, or soaks through it toward some stream or swamp below, provision must be made not only for drainage of your own field, but also for partial drainage of your neighbor's above, or at least for defence against his surplus of water.
The first, and leading idea to be kept in mind, as governing this question of the direction of drains, is the simple fact that water runs down hill; or, to express the fact more scientifically, water constantly seeks a lower level by the force of gravitation, and the whole object of drains is to open lower and still lower passages, into which the water may fall lower and lower until it is discharged from our field at a safe depth.
Water goes down, then, by its own weight, unless there is something through which it cannot readily pass, to bring it out at the surface. It will go into the drains, only because they are lower than the land drained. It will never go upward to find a drain, and it will go toward a drain the more readily, in proportion as the descent is more steep toward it.
To decide properly what direction a drain should have, it is necessary, then, to have a definite and a correct idea as to what office the drain is to perform, what water is to fall into it, what land it is to drain.
Suppose the general plan to be, to lay drains forty feet apart, and four feet deep over the field, and the question now to be determined, as to the direction, whether across, or up and down the slope, there being fall enough to render either course practicable. The first point of inquiry is, what is expected of each drain? How much and what land should it drain? The general answer must be, forty feet breadth, either up and down the slope, or across it; according to the direction. But we must be more definite in our inquiry than even this. From what forty feet of land will the water fall into the drain? Obviously, from some land in which the water is higher than the bottom of the drain.
If, then, the drain run directly across the slope, most of the water that can fall into it, must come from the forty feet breadth of land between the drain in question, and the drain next above it. If the water were falling on an impervious surface, it would all run according to the slope of the surface, in which case, by the way, no drains but those across, could catch any of it except what fell upon the drains. But the whole theory of drainage is otherwise, and is based on the idea that we change the course of the underground flow, by drawing out the water at given points by our drains; or, in other words, that "the water seeks the lowest level in all directions."
Upon the best view the writer has been able to take of the two systems as to the direction of drains, there is but a very small advantage in theory in favor of either over the other, in soil which is homogeneous. But it must be borne in mind that homogeneous soil is rather the exception in nature than the rule.
Without undertaking to advance or defend any peculiar geological views of the structure of the earth, or of the depositions or formations that compose its surface, it may be said, that very often the first four feet of subsoil is composed of strata, or layers of earth of varying porosity.
Beneath sand will be found a stratum of clay, or of compact or cemented gravel, and frequently these strata are numerous and thin. Indeed, if there be not some stratum below the soil, which impedes the passage of water, it would pass downward, and the land would need no artificial drainage. Quite often it will be found that the dip or inclination of the various strata below the soil is different from that of the surface.
The surface may have a considerable slope, while the lower strata lie nearly level, as if they had been cut through by artificial grading.
The following figure from the Cyclopedia of Agriculture, with the explanation, fully illustrates this idea.
"In many subsoils there are thin partings, or layers, of porous materials, interspersed between the strata, which, although not of sufficient capacity to give rise to actual springs, yet exude sufficient water to indicate their presence. These partings occasionally crop out, and give rise to those damp spots, which are to be seen diversifying the surface of fields, when the drying breezes of Spring have begun to act upon them. In the following cut, the light lines represent such partings.
"Now, it will be evident, in draining such land, that if the drains be disposed in a direction transverse or oblique to the slope, it will often happen that the drains, no matter how skillfully planned, will not reach these partings at all, as at A. In this case, the water will continue to flow on in its accustomed channel, and discharge its waters at B.
"But again, even though it does reach these partings, as at C, a considerable portion of water will escape from the drain itself, and flow to the lower level of its old point of discharge at D. Whereas, a drain cut in the line of the slope, as from D to E, intersects all these partings, and furnishes an outlet to them at a lower level than their old ones."
These reasons are, it is true, applicable only to land of peculiar structure; but there are reasons for selecting the line of greatest fall for the direction of drains which are applicable to all lands alike.
"The line of the greatest fall is the only line in which a drain is relatively lower than the land on either side of it." Whether we regard the surplus water as having recently fallen upon the field, and as being stopped near the surface by an impervious stratum, or as brought down on these strata from above, we have it to be disposed of as it rests upon this stratum, and is borne out by it to the surface.
If there is a decided dip, or inclination, of this stratum outward down the slope, it is manifest that the water cannot pass backward to a cross drain higher up the slope. The course of the water must be downward upon the stratum on which it lies, and so all between two cross drains must pass to the lower one. The upper drain could take very little, if any, and the greater the inclination of this stratum, the less could flow backward.
But in such case a drain down the slope gives to the water borne up by these strata, an outlet of the depth of the drain. If the drain be four feet deep, it cuts the water-bearing strata each at that depth, and takes off the water.
In these cases, the different layers of clay or other impervious "partings," are like the steps of a huge stairway, with the soil filling them up to a regular grade. The ditch cuts through these steps, letting the water that rests on them fall off at the ends, instead of running over the edges. Drains across the slope have been significantly termed "mere catch-waters."
If we wish to use water to irrigate lands, we carefully conduct it along the surface across the slope, allowing it to flow over and to soak through the soil. If we desire to carry the same water off the field as speedily as possible, we should carry our surface ditch directly down the slope.
Now, looking at the operation of drains across the slope, and supposing that each drain is draining the breadth next above it, we will suppose the drain to be running full of water. What is there to prevent the water from passing out of that drain in its progress, at every point of the tiles, and so saturating the breadth below it? Drainpipes afford the same facility for water to soak out at the lower side, as to enter on the upper, and there is the same law of gravitation to operate in each case. Mr. Denton gives instances in which he has observed, where drains were carried across the slope, in Warwickshire, lines of moisture at a regular distance below the drains. He could ascertain, he says, the depth of the drain itself, by taking the difference of height between the line of the drain at the surface, and that of the line of moisture beneath it. He says again:
"I recently had an opportunity, in Scotland, of gauging the quantity of water traveling along an important drain carried obliquely across the fall, when I ascertained with certainty, that, although the land through which it passed was comparatively full of water, the drain actually lost more than it gained in a passage of several chains through it."
So far as authority goes, there seems, with the exception of some advocates of the Keythorpe system, of which an account has been given, to be very little difference of opinion. Mr. Denton says:
"With respect to the direction of drains, I believe very little difference of opinion exists. All the most successful drainers concur in the line of the steepest descent, as essential to effective and economical drainage. Certain exceptions are recognized in the West of England, but I believe it will be found, as practice extends in that quarter, that the exceptions have been allowed in error."
In another place, he says:
"The very general concurrence in the adoption of the line of greatest descent, as the proper course for the minor drains in soils free from rock, would almost lead me to declare this as an incontrovertible principle."
Allusion has been made to cases where we may have to defend ourselves from the flow of water from higher undrained lands of our neighbor. To arrest the flow of mere surface water, an open ditch, or catch-water, is the most effectual, as well as the most obvious mode. There are many instances in New England, where lands upon the lowest slopes of hills are overflowed by water which fell high up upon the hill, and, after passing downward till arrested by rock formation, is borne out again to the surface, in such quantity as to produce, just at the foot of the hill, almost a swamp. This land is usually rich from the wash of the hills, but full of cold water.
To effect perfect drainage of a portion of this land, which we will suppose to be a gentle slope, the first object must be to cut off the flow of water upon or near the surface. An open ditch across the top would most certainly effect this object, and it may be doubtful whether any other drain would be sufficient. This would depend upon the quantity of water flowing down. If the quantity be very great at times, a part of it would be likely to flow across the top of an under-drain, from not having time to percolate downward into it.
In all cases, it is advised, where our work stops upon a slope, to introduce a cross-drain, connecting the tops of all the minor-drains. This cross-drain is called a header. The object of it is to cut off the water that may be passing along in the subsoil down the slope, and which would otherwise be likely to pass downward between the system of drains to a considerable distance before finding them. If we suppose the ground saturated with water, and our drains running up the slope and stopping at 4 feet depth, with no header connecting them, they, in effect, stop against 4 feet head of water, and in order to drain the land as far up as they go, must not only take their fair proportion of water which lies between them, but must draw down this 4 feet head beyond them. This they cannot do, because the water from a higher source, with the aid of capillary attraction, and the friction or resistance met with in percolation, will keep up this head of water far above the drained level.
In railway cuttings, and the like, we often see a slope of this kind cut through, without drying the land above the cutting; and if the slope be disposed in alternate layers of sand or gravel, and clay, the water will continue to flow out high up on the perpendicular bank. Even in porous soils of homogeneous character, it will be found that the head of water, if we may use the expression, is affected but a short distance by a drain across its flow. Indeed, the whole theory as to the distance of drains apart, rests upon the idea, that the limit to which drains may be expected effectually to operate, is at most but two or three rods.
Whether, in a particular case, a header alone will be sufficient to cut off the flow of water from the higher land, or whether, in addition to the header, an open catch-water may be required, must depend upon the quantity of water likely to flow through or upon the land. An under-drain might be expected to absorb any moderate quantity of what may be termed drainage-water, but it cannot stop a river or mill-stream; and if the earth above the tiles be compact, even water flowing through the soil with rapidity, might pass across it. If there is reason to apprehend this, an open ditch might be added to the header; or, if this is not considered sufficiently scientific or in good taste, a tile-drain of sufficient capacity may be laid, with the ditch above it carefully packed with small stones to the top of the ground. Such a drain would be likely to receive sand and other obstructing substances, as well as a large amount of water, and should, for both reasons, be carried off independently of the small drains, which would thus be left to discharge their legitimate service.