more in a given time than a similar hole bored at the "depth of two feet, so will a 4-foot drain discharge in a 66 given time much more water than a drain of two feet. "One is acted on by a 4-foot, and the other by a 2-foot 'pressure."

If any single fact connected with tile-drainage is established, beyond all possible doubt, it is that in the stiffest clay soils ever cultivated, drains four feet deep will act effectually; the water will find its way to them, more and more freely and completely, as the drying of successive years, and the penetration and decay of the roots of suc cessive crops, modify the character of the land, and they will eventually be practically so porous that,-so far as the ease of drainage is concerned,-no distinction need, in practice, be made between them and the less retentive loams. For a few years, the line of saturation between the drains, as shown in Fig. 11, may stand at all seasons considerably above the level of the bottom of the tile, but it will recede year by year, until it will be practically level, except immediately after rains.

Mr. Josiah Parkes recommends drains to be laid

"At a minimum depth of four feet, designed with the two-fold object of not only freeing the active soil from stagnant and injurious water, but of converting the water falling on the surface into an agent for fertiliz ing; no drainage being deemed efficient that did not both remove the water falling on the surface, and keep down the subterranean water at a depth exceeding the power of capillary attraction to elevate it near the surface.'"

Alderman Mechi says:

"Ask nineteen farmers out of twenty, who hold strong clay land, and they will tell you it is of no use placing deep four-foot drains in such soil -the water cannot get in; a horse's foot-hole (without an opening under it) will hold water like a basin; and so on. Well, five minutes after, you tell the same farmers you propose digging a cellar, well bricked, six or eight feet deep; what is their remark? Oh! it's of no use your making an underground cellar in our soil, you can't keep the water OUT!' Was there ever such an illustration of prejudice as this? What is a drain pipe but a small cellar full of air? Then, again, common sense tells us, you can't keep a light fluid under a heavy one. You might as well try to keep a cork under water, as to try and keep air under

water. 'Oh! but then our soil is n't porous.' If not, how can it hold water so readily? I am led to these observations by the strong contro versy I am having with some Essex folks, who protest that I am mad, or foolish, for placing 1-inch pipes, at four-foot depth, in strong clays. It is in vain I refer to the numerous proofs of my soundness, brought forward by Mr. Parkes, engineer to the Royal Agricultural Society, and confirmed by Mr. Pusey. They still dispute it. It is in vain I tell them I cannot keep the rainwater out of socketed pipes, twelve feet deep, that convey a spring to my farm yard. Let us try and convince this large class of doubters; for it is of national importance. Four feet of good porous clay would afford a far better meal to some strong bean, or other tap roots, than the usual six inches; and a saving of $4 to $5 per acre, in drainage, is no trifle.

"The shallow, or non-drainers, assume that tenacious subsoils are impervious or non-absorbent. This is entirely an erroneous assumption. If soils were impervious, how could they get wet?

"I assert, and pledge my agricultural reputation for the fact, that there are no earths or clays in this kingdom, be they ever so tenacious, that will not readily receive, filter, and transmit rain water to drains placed five or more feet deep.

"A neighbor of mine drained twenty inches deep in strong clay; the ground cracked widely; the contraction destroyed the tiles, and the rains washed the surface soils into the cracks and choked the drains. H has since abandoned shallow draining.

"When I first began draining, I allowed myself to be overruled by my obstinate man, Pearson, who insisted that, for top water, two fee was a sufficient depth in a veiny soil. I allowed him to try the exper. ment on two small fields; the result was, that nothing prospered; and I am redraining those fields at one-half the cost, five and six feet deep at intervals of 70 and 80 feet.

"I found iron-sand rocks, strong clay, silt, iron, etc., and an enor mous quantity of water, all below the 2-foot drains. This accounted at once for the sudden check the crops always met with in May, when they wanted to send their roots down, but could not, without going into stag. nant water."

"There can be no doubt that it is the depth of the drain which regu lates the escape of the surface water in a given time; regard being had, as respects extreme distances, to the nature of the soil, and a due capacity of the pipe. The deeper the drain, even in the strongest soils, the quicker the water escapes. This is an astounding but certain fact:

"That deep and distant drains, where a sufficient fall can be obtained, are by far the most profitable, by affording to the roots of the plants a greater range for food."

Of course, where the soil is underlaid by rock, less tnau four feet from the surface; and where an outlet at that depth cannot be obtained, we must, per force, drain less

deeply, but where there exists no such obstacle, drains should be laid at a general depth of four feet,-general, not uniform, because the drain should have a uniform in clination, which the surface of the land rarely has.

The Distance between the Drains.-Concerning this, there is less unanimity of opinion among engineers, than prevails with regard to the question of depth.

In tolerably porous soils, it is generally conceded that 40 or even 50 feet is sufficiently near for 4-foot drains, but, for the more retentive clays, all distances from 18 feet to 50 feet are recommended, though those who belong to the more narrow school are, as a rule, extending the limit, as they see, in practice, the complete manner in which drains at wider intervals perform their work. A careful consideration of the experience of the past twenty years, and of the arguments of writers on drainage, leads to the belief that there are few soils, which need draining at all, on which it will be safe to place 4-foot drains at much wider intervals than 40 feet. In the lighter loams there are many instances of the successful application of Professor Mapes' rule, that "3-foot drains should be "placed 20 feet apart, and for each additional foot in "depth the distance may be doubled; for instance, 4-foot "drains should be 40 feet apart, and 5-foot drains 80 feet apart." But, with reference to the greater distance, (80 feet,) it is not to be recommended in stiff clays, for any depth of drain. Where it is necessary, by reason of insufficient fall, or of underground rock, to go only three feet deep, the drains should be as near together as 20 feet.

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At first thought, it may seem akin to quackery to reo ommend a uniform depth and distance, without reference to the character of the land to be drained; and it is unquestionably true that an exact adaptation of the work to the varying requirements of different soils would be beneficial, though no system can be adopted which will make

clay drain as freely as sand. The fact is that the adjust ment of the distances between drains is very far from partaking of the nature of an exact science, and there is really very little known, by any one, of the principles on which it should be based, or of the manner in which the bearing of those principles, in any particular case, is affected by several circumstances which vary with each change of soil, inclination and exposure.

In the essays on drainage which have been thus far published, there is a vagueness in the arguments on this branch of the subject, which betrays a want of definite conviction in the minds of the writers; and which tends quite as much to muddle as to enlighten the ideas of the reader. In so far as the directions are given, whether fortified by argument or not, they are clearly empirical, and are usually very much qualified by considerations which weigh with unequal force in different cases.

In laying out work, any skillful drainer will be guided, in deciding the distance between the lines, by a judgment which has grown out of his former experience; and which will enable him to adapt the work, measurably, to the requirements of the particular soil under consideration; but he would probably find it impossible to so state the reasons for his decision, that they would be of any genera! value to others.

Probably it will be a long time before rules on this subject, based on well sustained theory, can be laid down with distinctness, and, in the mean time, we must be guided by the results of practice, and must confine ourselves to distance which repeated trial, in various soils, has proven to be safe for all agricultural land. In the drainage of the Central Park, after a mature consideration of all that had been published on the subject, and of a considerable previous observation and experience, it was decided to adopt a general depth of four feet, and to adhere as closely as possible to a uniform distance of forty feet. No instance

was known of a failure to produce good results by drain. ing at that distance, and several cases were recalled where drains at fifty and sixty feet had proved so inefficient that intermediate lines became necessary. After from seven

to ten years' trial, the Central Park drainage, by its results, has shown that, although some of the land is of a very retentive character, this distance is not too great; and it is adopted here for recommendation to all who have no especial reason for supposing that greater distances will be fully effective in their more porous soils.

As has been before stated, drains at that distance, (or at any distance,) will not remove all of the water of saturation from heavy clays so rapidly as from more porous soil; but, although, in some cases, the drainage may be insufficient during the first year, and not absolutely per fect during the second and third years, the increased porosity which drainage causes, (as the summer droughts make fissures in the earth, as decayed roots and other organic deposits make these fissures permanent, and as chemical action in the aërated soil changes its character,) will finally bring clay soils to as perfect a condition as they are capable of attaining, and will invariably render them excellent for cultivation.

The Direction of the Laterals should be right up and down the slope of the land, in the line of steepest descent. For a long time after the general adoption of thoroughdraining, there was much discussion of this subject, and much variation in practice. The influence of the old rules for making surface or "catch-water" drains lasted for a long time, and there was a general tendency to make tile drains follow the same directions. An important requirement of these was that they should not take so steep an inclination as to have their bottoms cut out and their banks undermined by the rapid flow of water, and that they should arrest and carry away the water flowing down over the surface of hill sides. The arguments for the