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500 



li<*ht earth immediately over a substratum of clay, and after continued rains 

 in- soil becomes filled with water, like a sponge, and no healthy vegetation 

 can take place. In this case numerous drains must be made in the subsoil, and 

 over the draining tiles or bushes, which may be laid at the bottom of the drains, 

 loose gravel or broken stones must be laid in to within a foot of the surface, so 

 thai the plough shall not reach them. The water will gradually sink into these 

 drains, and be carried off, and the loose wet soil will become firm and dry. In 

 no case is the advantage of draining more immediately apparent. 



It is very seldom that a field is absolutely level; the first thing therefore to 

 be ascertained is the greatest inclination and its direction. For this purpose 

 there is an instrument essential to a drainer, with which an accurately hori- 

 zontal line can be ascertained, by means of a plummet or a spirit level. A suf- 

 ficient fall may thus be found or artificially made in the drains to carry off' the 

 water. The next object is to arrange drains so that each shall collect as much 

 of the water in the soil as possible. Large drains, except as main drains, are 

 inadmissible, since it is by the surface that the water is to come in, and two 

 small drains will collect more than a larger and deeper. The depth should be 

 such only that the plough may not reach it, if the land is arable, or the feet of 

 cattle tread it in, il it be in pasture. All the drains which are to collect the 

 water should lie as nearly at right angles to the inclination of the surface as is 

 consistent with a sufficient fall in the drains to make them run. One foot is 

 sufficient fall for a drain 300 feet in length, provided the drains be not more 

 than 20 feet apart. The main drains, by being laid obliquely across the fall of 

 the ground, will help to take off a part of the surface water. It is evident that 

 the drains can seldom be in a straight line, unless the ground be perfectly even. 

 They should, however, never have sudden turns, but be bent gradually where 

 the direction is changed. The flatter the surface and the stiffer the soil, the 

 greater number of drains will be required. It is a common practice with 

 drainers to run a main drain directly down the slope, however rapid, and to 

 carry smaller drains into this alternately on the right and left, which they call 

 herring-bone fashion. But this can only be approved of where the ground is 

 nearly level, and where there is very little fall for the main drain. A con- 

 siderable fall is to be avoided as much as possible; and every drain should lie 

 obliquely to the natural run of the water. It generally happens that, besides 

 surface water, there are also some land springs arising from a variation in the 

 soil; these should be carefully ascertained, and the drains should be so laid as 

 to cut them off. 



In draining clay land, where there is only a layer of a few inches of loooser 

 soil over a solid clay which the plough never stirs, the drains need not be 

 deeper than two feet in the solid clay, nor wider than they can be made with- 

 out the sides falling in. The common draining tile, which is a flat tile bent in 

 the form of half a cylinder, and which can be made at a very cheap rate with 

 the patent machine, is the best for extensive surface draining. In solid clay it 

 requires no flat tile under it, it is merely an arch to carry the loose stones or 

 earth with which the drain is filled up. Loose round stones or pebbles are the 

 best where they can be procured; and in default of them, bushes, heath, or 

 straw, may be laid immediately over the tiles, and the most porous earth that 

 can be got must be used to fill the drains up: the stiff clay which was dug out 

 must be taken away or spread over the surface; for if it were put in the drain, 

 it would defeat the object in view by preventing the water from running into 

 it from above. In grass land, the sod may be laid over the drain, after it has 

 been filled up so as to form a slight ridge over it. This will soon sink to a level 

 with the surface, and in the mean time serves to catch the water as it runs 

 down. To save the expense of stone or tiles, drains are frequently made six 

 inches wide at the bottom, a narrow channel is cut in the solid clay, two or 

 three inches wide and six deep, leaving a shoulder on each side to support a 

 sod which is cut so as to fit the drain, and rests on the shoulders: this sod keeps 

 the earth from filling the channel; and the water readily finds its way through 

 it, or between it and the sides of the drain. It is filled up as described before: 

 such drains are made at a small expense, and will last for many years. 

 _ Where the clay is not sufficiently tenacious, the bottom of the drain is some- 

 times cut with a sharp angle, and a twisted rope of straw is thrust into it. 



