DRAINS

DRAINS. Under this word in the Encyclopædia we published Mr Bayley of Hope's method of draining land; and by a letter from the author, we have since learned, that experience, the best guide, has fully proved the usefulness and durability of his drains. With a candour, however, worthy of a man who writes not for fame, but for the good of the public, he informs us of a mistake into which he had led us; and requests us to correct it in this Supplement.

"I wish (says he) that, in the Supplement to the Encyclopædia, due notice may be taken of a very great error into which I was led in my scheme of making the main drains. I conjectured, that where the bottom of the trench was of a hard or solid body, as clay or marl, it might not be necessary to lay it with bricks or stones; but in this I was quite wrong. By the runs of water, the alternate changes from wet to dry, and the access

of air, these hard bottoms have been rendered friable; they have crumbled away, and let in all my drains which were not supported by a bottom laid with brick or stone." For this information we request the author to accept of our thanks, and we are persuaded we may add, the thanks of the public.

As the draining of land is a matter of great importance in agriculture, and as the subject has been again brought before us, we imagine that our agricultural readers will be glad to find here the substance of a paper on this subject, for which the author received the silver medal of the Society instituted for the encouragement of ARTS, MANUFACTURES, and COMMERCE. That author is Mr JOHN WEDGE of Bickenhill, near Coventry, who is not only a great farmer himself, but had likewise been employed by the Earl of Alesford in the management of several estates. Encouraged by his lordship's liberality, Mr Wedge informs the society, that he had been employed for some years in draining large portions of land, of which part was in the Earl's occupation, and part in his own, as tenant to his lordship. The principles upon which he proceeded, as well as his mode of procedure, he states in the following terms:

In every country there are large portions of land that, in wet seasons, have always what may be called a dry surface, and other portions of land that have always a moist or wet surface; the former of these admitting all the water which falls upon them to sink freely through their pores to various depths, till falling on clay, or some other unctuous earth, whose pores will not permit it to pass through, it is there held up to a height proportioned to the quantity of water which comes upon it, and the facility with which that water is discharged. Thus, held up to various heights, it serves as a fountain to distribute its water (either by veins of sand, pebbles, or rock), according to the formation of the different under strata on the neighbouring lands, and there forms bogs and other varieties of wet surface, on a basis that will be always found to consist of marl, or clay, or some mixture thereof. The effect of water thus distributed may be divided into two classes. The first class, where the water is thrown out by a body of marl or clay, &c. upon the surface of descending ground, and in the valley (there held up by clay also) forms bogs or swamps. The second class, where the water is held up by marl or clay, as before, having above that marl or clay a stratum of sand, or pebbles, through which the water passes; and above those sands or pebbles another stratum of marl or clay, through the weakest parts of which the water, by a continual pressure from its fountain, forces a passage upwards; and thus, through the weakest parts of the marl or clay, furnishes a continual supply of water on the surface, for the formation or growth of bogs, &c. in proportion as this water is more or less abundantly supplied by its fountain or head, namely, the higher lands, into which rain-water freely passes, as before described. There are also different soils, under different circumstances, which may form a third class of land for draining; such as, strong deep soils, or open light soils, having near the surface a body of marl or clay. In either of these cases, the water which falls on the surface must, for reasons which are self-evident, keep such lands, in rainy seasons, constantly wet and cold; and it should be observed, that a mixture of all the three before-described classes of wet land sometimes occur in one field, by sud-

den alterations of the under strata, and thereby perplex the operator, by requiring all the different modes of draining in the same field.

If it be admitted that bogs are thus formed and fed, their cure may be effected with certainty. The first class, by cutting through the stratum (be it sand, pebbles, or rock,) that conveys the water to the bog, and carrying off that water by a close drain to some proper place, where the level admits of its discharge. The second class, by sinking a drain to any convenient depth in the upper clay; and then digging or boring with a large auger, at a small distance on one side of this drain, through the remaining part, be it (the upper clay) ever so deep, into the under stratum of sand, pebbles, or rock, through which the water passes; which will then rush up into the drain so made, with a velocity proportioned to the height of the land or fountain whence it is supplied. As this drain advances through the land, holes must be dug or bored, as before, every seven yards, or at such distance as the strength of the springs may require; and the whole of the water thus brought up by tapping the springs, is carried off by the drain made in the upper clay, which must be a close one, to its proper level, and there discharged.

By both these methods of draining, large tracts of land, under favourable circumstances, may be cured with one drain. The best place for fixing these drains is where the stratum that conveys the water comes nearest to the surface; and the best method of ascertaining that, is to bore or dig in different parts through the different under strata.

The third class may be easily cured by close drains, at such distances and depths as will best carry off the surface-water. It may not be improper to observe, that where the different strata or measures crop out, that is, become gradually more and more shallow in some certain direction (as is often the case, till, one after the other, they all present themselves in succession on the surface of the earth), draining may often be much more easily and better effected by crossing with the drain the different strata or measures where the levels and other circumstances will admit.

Some of the land drained was part of a common, in the parish of Church Bickenhill, in the county of Warwick; part of it was covered with moss and ling, had a peaty surface about six inches deep, and produced little or no grass; in all wet seasons it was filled quite to the surface, and often overflowed, with water. Some of the land was much more unfound, deeper of peat, and covered with moss, in most parts nine inches long; another part was an absolute bog in all seasons.

Having dug or bored with a large auger into several parts of the land, Mr Wedge found peat, gravel, and sand mixed, and a quick-sand almost uniformly. The quick-sand in every part, after getting an inch or two into it, seemed almost as fluid as water. Judging from this, that no materials for a drain could be laid in the quick-sand, but what it would immediately bury, he dug a trench almost to the quick-sand, leaving gravel, &c. of sufficient strength to bear up the materials for a hollow drain; these materials were two sides and a cover of stone, with a peat-turf on the top to keep out the soil. At every seven yards forward, by the side of this drain, he dug a hole in the quick-sand as deep as it would permit. From these holes the water rose free-

ly into the hollow drain, and was by it discharged at a proper level. It may be proper to remark, that the stone made use of for this drain, and all others here mentioned, was a red sand and rag-stone, which easily split into proper sizes for the purpose, and is very durable; it cost about sixpence per ton getting, exclusive of carriage. The drain thus formed ran on the whole rather freely, and made the land dry for a few yards on each side thereof, but was far from having the effect he improperly expected; for it evidently appears that the drain could only take a very small portion of the water from so large a quick-sand, which it did not penetrate more than two inches; and that it could drain only to its own depth, or, at most, to that depth in the fountain which supplied the quick-sand. His purpose was then defeated; and his motive for mentioning this error cannot, he hopes, be mistaken.

He now did what he says he ought to have done before, that is, examined the different strata to a greater depth, particularly on the bog, and at the upper edges thereof, and found the bog to be what has been described under the first class. He therefore determined to attempt the cure in the manner before prescribed for that class, namely, to cut through the whole of the stratum (in this instance, of quick-sand) through which he found the water pass. This he effected as follows: The summer being dry, and favourable for the purpose, and having previously made his main open drain, he began his main close drain the first week in June 1791, three feet wide, on the declivity near the edge of the great bog. In the first operation he dug through the peat, the hard sand, and gravel, and one spade's graft (about nine inches deep, and seven inches wide) into the quick-sand the whole length of this drain, which was 73 perches, of eight yards to the perch, in length. The drain thus dug ran copiously, not less than 60 gallons per minute. In this state he left it about nine days; the effect of it was rapid, both above the drain and on the bog below. Upon examination, he now found about three inches on the top of the spade's graft, which had been made into the quick-sand, perfectly dry. He then dug out these three inches of dry sand, to nearly the whole width of the drain, three feet; and at the same time dug out, as before, another spade's graft from the top of the quick-sand, as near the middle of the drain as possible. This was left to run a few days, as before, and had the same effect, namely, three or four inches more of the top of the quick-sand became dry and hard. The same operation was repeated again and again with the same effect, till the purpose of getting through this quick-sand was completed, so far at least as the level of the main open drain would permit. The stream of water continued increasing during the whole operation; the bog below the drain was quite dry, and the land above perfectly so. The drain which was first made, and continued running for some time during the progress of the main close drain, became gradually dry; and has not, since that drain was finished, discharged one single drop of water. Great care was necessary, in making the main close drain, to keep the stream of water in the middle of it, otherwise the current would have undermined the sides, as it sometimes had done, and caused them to fall in. For this reason it was necessary, when the dry sand was taken from the top of the quick-sand, immediately to take out a spade's graft from

Drains. the middle thereof, in order to divert the current from the sides.

The main close drain thus made was three feet wide at top, about nine feet deep on the average, and, beveling a little from the top, it was about one foot ten inches wide at the bottom. The stone and other materials were put into this drain in the following manner:

Where the drain went through the quick sand into the stratum of clay below it, as in most places it did, the bottom, and in some instances the sides, wanted no particular security (A); but where it did not go quite through the quick sand, which the level of his main open drain in some places would not admit, the bottom of the drain was covered half an inch thick with ling; then peat-turfs, one foot wide and three or four inches thick, were cut in convenient lengths, and placed on their edges on each side of the bottom of the drain, forming two sides of a trough of peat; then side stones about eight inches high, and a stone coverer, were put in upon the ling between the peat turfs; a large peat-turf, near two feet wide and four inches thick, was then cut and firmly placed over the whole: this left in the bottom of the drain an open space, of more than six inches square, for the water to pass. The whole was then completed by filling in the upper part of the drain.

In this way the author drained, for about L. 80, thirty acres of land, which, from being of no value whatever, became worth at least 14 shillings per acre of yearly rent. He likewise hollow-drained nine acres by the method prescribed for the third class of wet land. These drains were made a few yards below that part of each field where the dry and wet land separate, about 22 inches deep, with sides and a coverer of stone, and ling on the top of it, to keep the earth from running in. The length of these drains was 880 yards, and the expense of labour and materials three halfpence per yard. The drains, in wet weather, discharge a large quantity of water; and will, he has no doubt, answer the intended purpose. Thus far relates to land in his own occupation.

Nine acres of the land in the earl of Aylesford's occupation was almost an entire pulp. This bog was of the second class, namely, water passing through a quick-sand, and confined by a stratum of clay below, and another stratum of clay above it. The water thus confined, being pressed by its fountain, and forced up thro' the weakest parts of the clay, had formed a bog of irregular thickness on the surface, in some places six feet deep, in others not more than two. As there is a considerable fall in this land from east to west, he thought it expedient to put two drains into it; and this appears to him to have been necessary, from a consideration that both these drains continue to run in the same proportions as when first opened. The manner in which these drains were executed was, by digging through the different upper strata, and as deep into the clay as the main open drain would admit; then digging or boring through the remaining part of that clay into the quick-sand, at the distance of about six yards, in a progressive manner.

Drains. The water rising rapidly through these holes into the close drains, has effected a complete cure of this land, every part of which will now bear a horse to gallop upon it. These drains discharge 3660 gallons an hour; which is much less than they did at first, as must be the case in all bogs. This land will be worth twenty shillings per acre. The draining cost twenty-five pounds; and the length of the under-ground drains is eight hundred and fourteen yards.

Mr Wedge had just finished (January 1792) draining another piece of land, about forty-three acres. As this was intended to answer two purposes, one, to drain the land, the other, to give an additional supply of water to a mill-pool, and as a circumstance arose in the execution of the work which frequently happens in draining land, namely, a sudden alteration in the position of the under strata—a description thereof will not, we hope, be thought tedious. This draining was begun at the level of a mill-pool, and continued, without any great difficulty, to the distance of about thirty-two chains, in the manner before described as a cure for the second class of boggy land: but at or near that place the under strata altered their position; the quick-sand which conveyed the water now became of twice its former thickness; and the clay, which had hitherto been above that quick-sand, for some distance disappeared. From the quick sand thus becoming so much deeper, he could not, with the level of the mill-pool, cut through it; nor indeed, from the wetness of the season, would such an operation have been proper. He therefore continued a shallow drain to some distance, making side-holes into the quick-sand, which ran freely; but as this could not cure the whole of the bog below, he branched out another drain (which was made by the method described for curing the second class of wet or boggy land), by sinking a close drain through the upper strata into the upper clay, and then, at a small distance on one side of this close drain, boring a hole with an auger through the remaining part of that clay into the quick-sand; and at every eight yards, as this close drain advanced, still boring other holes, in the manner before described: through many of these holes the water rushed with great rapidity. The water discharged by these drains into the mill-pool is 168 gallons per minute, or 3780 hogsheds in a day; which is after the rate of 1,379,700 hogsheds in a year.

About six acres of this land were always found; about twelve acres on the north side were an absolute pulp, and the remaining twenty-six acres very unfound. The whole is now found, and will when cultivated be worth sixteen shillings per acre. This land would have been drained at a much less expense into the main open drain; but then the water, which was much wanted for the mill, would have been lost. These close drains are in length 1452 yards, and cost L. 100, of which about L. 30 ought to be charged to the mill.

Important as this subject is, we must not enlarge this article, or we should make large extracts from Dr Anderson's Practical Treatise on Draining Bogs and Swampy Grounds, lately published. It is proper, however, to inform the public, that the author puts in his claim for

for being the first discoverer of that mode of draining for which Mr Elkington has obtained from parliament a premium of £1000; and the reader who shall turn to the article DRAINS in the Encyclopædia, will perceive that his claim is well-founded.