DRAINING. 



DRAIMMi. 



hollow and carried round it will prevent the water running down into 



1 funning a marsh at the bottom. 



Whan the dnina cannot be carried to a cmfficimt depth to take the 

 water out of the poroui stratum saturated with it, it u often uaeful to 

 bora numerous hole* with an auger in the bottom of the drain through 

 UM atiflVr toil ; and. according to the principle explained in the 

 diagram. UM water will either rise through these bom into the drain* 

 and be carried off, and the natural pring will be dried up, or it will 

 ink down through them as at u, in the auction, if it lie* above. This 

 method ia often adrantageoua in the draining of peat moweo, which 

 generally lie on clay or atiff loam, with a layer of gravel between the 

 um tod the peat, the whole lying in a baain or hollow, and often on 

 declivity. The |>eat, though it retains water, u not pervious, and 

 drain* may be cut into it which will hold water. When the drains are 

 four or Are feet deep and the peat U much deeper, holes are bored 

 down to the clay below, and the water is preaied up through these 

 hnlat. by the weight of the whole body of peat, into the drains, by 

 which it is carried off. The bottom of the drains u sometimes choked 

 with loose sand, which HI-WH up with the water, and they require to 

 be cleared repeatedly ; but this noon ceases after the first rush is past, 

 and the water rises slowly and gradually. The surface of the pit being 

 dried, dressed with lime, and consolidated with earth and gravel, soon 

 becomes productive. If the soil, whatever be ita nature, can be drained 

 to a certain depth, it i- of u > consequence what water may be lodged 

 below it. It u only when it rises so as to stagnate about the roots of 

 (ilantu that it in hurtful. 



When a single large and deep drain will produce the desired effect, it 

 in much better than when there are several smaller, as large drains are 

 more easily kept open and last longer than smaller ; but thin is only 

 the case in tapping main springs, for if the water is diffused through 

 the surrounding soil, numerous small drains are more effective. But 

 as soon as there is a sufficient body of water collected, the smaller 

 drains should run into larger, and these into main drains, which should 

 all, as far as is practicable, unite in one principal outlet, by which 

 means there will be leas chance of their being choked up. When the 

 water springs into a drain from below, it is best to fill up that port of 

 the drain which lies above the stones or other materials which form the 

 channel with solid earth well pressed in, and made impervious t<> 

 within a few inches of the bottom of the furrows in ploughed land, ur 

 the sod in pastures ; because the water running along the surface is 

 apt to carry loose earth with it, and choke the drams. When the 

 water comes in by the side of the drainx, loose stones or gravel, or any 

 porous material, should be laid in them to the line where the water 

 comes in, and a little above it, over which the earth may bo rammed 

 in tight, so as to allow the horses to walk over the drain without 



Mtilring in. 



It sometimes happens, that the water collected from springs which 

 caused marshes and bogs below, by being carried in new channels, may 

 bo usefully employed in irrigating the land which it rendered barren 

 before ; not only removing the cause of barrenness, but adding positive 

 fertility. In thU case the lower ground must have numerous drains 

 in it, in order that the water let on to irrigate it may not stagnate upon 

 it, but run off after it has answered its purpose. 



The third branch in the art of draining ia the removal of water fruu 

 impervioua soils which lie flat, or in hollows, where the water from 

 rain, snow, or dews, which cannot xiuk into the soil on account of its 

 impervious nature, and which cannot be carried off by evaporation 

 runs along the surface and stagnates in every depression. This is bj 

 far the most expensive operation, in consequence of the number o 

 drains required to lay the surface dry, and the necessity of filling 

 them with porous substances, through which the surface water can 

 penetrate. 



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 horizontal line can be iiscertained, by means of a 

 plummet or a spirit-level. A sufficient fall may thus be found or 

 artificially made in the drain* to carry off the water. One foot is 

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

 more than 20 feet apart. U is evident that the drains cannot always 

 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 stiller 

 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 th. 

 right and left, which they call herring-bone fashion. But this can 

 rarely be approved of. It generally happens that, besides surface 

 water, there are also some land spring! arising from a variation in the 

 these should be carefully ascertained, and the drains should be so 

 kid as to cut them oft 



The following memoranda are suggestive of the principles which 

 nhould guide practice on the subject ; and may serve also to indicate 

 directly what correct practice generally is : 



Food enters plants chiefly as dissolved in water. The relations of 



to the plant and to the soil are therefore of the first importance. 



i * r>we- f . extracting soluble nutters from the air 



and i. Uich it passes. The air in rain-water con- 



tains one half more oxygen, and three to six times more carbonic acid 

 than the air of the atmosphere. Rain-water also contains nitric acid 



!..:.. 



The contents of rain-water, its solvent powers exerted on the 

 mineral and other matters useful as food for plants in the soil, and its 

 relations to temperature, are the three pouts on which its fertilising 

 nfluencw depend. 



Water gets into land in three ways: 1st, as rain falling on the 

 surface ; 2nd, as spring water ; 3rd, by capillary attraction exerted on 

 a wet subsoil. 



Water leaves the land in three ways : 1st, by running off its surface ; 

 2nd, by evaporating from its surface ; 3rd, by percolating through its 

 substance. In the first case it is wholly inoperative, except in so far a* 

 it does mischief by carrying off the finer surface particles of the soil 

 either in solution or otherwise. In the second case it carries off, in 

 great measure to waste, matters capable of evaporation, and useful as 

 fo,,l fur plants, which it holds in solution ; but the most considerable 

 result of evaporation is the loss of heat consequent upon it As much 

 heat as the burning of two or three ounces of coal could produce is 

 the evaporation of 1 Ik <.f water. Dalton's gauge indicated an 

 annual evaporation of 24 inches out of 33 inches of an annual rainfall. 

 Dickenson's gauge indicated an evaporation of 15 out of 26. During 

 percolation through the land, which is the third way in which water 

 leaves the soil, it introduces into the land the temperature of the air, 

 it introduces atmospheric elements into the soil, it dissolves food out 

 of the land and carries it to the roots of plants. 



The principal practical from drainage U the easier 



and cheaper cultivation of which drained land is capable. The greater 

 fertility of such land is in a measure due to the whole substance 

 its whole internal surface being brought under the influence of air and 

 rain-water. 



The object of drainage then ia to induce the percolation of 

 water through the soil. To this end conduits are laid under ground at 

 such a depth and at such intervals as experience finds sufficient. And 

 the points connected with the practice to be conndered are (1 

 depth, an limited by the outfall, as desirable in the interests of fei 

 and as necessary owing to the constitution of the soil; (2), the 

 frequency and capacity of the drain to correspond with the raiu-fall 

 and. with the character of the soil; (>, the arrangement of th. 

 drains, uniform to correspond with the uniformity of the supply in 

 rain, or irregular to correspond with the subsequent irregular distribu- 

 tion of the rain-water throughout the soil. 



(1). As to depth its principal limit is cost that it should '> 

 siderable is desirable on the ground of the gn at. i <l< pth of material 

 being thus fertilised and made useful to the plant. Drains 2 

 and 4 feet deep may, other things being equal, cost 31., and !< 

 51. per acre but there are thus brought into use 18, SO, and 42 

 hundred tons of earth per acre, which U after the rate of 600, 700, and 

 800 tons for every pound of expenditure so that the deeper anil 

 costlier drain may be the cheaper in the end. But depth is regulated 

 to some extent by the capillary attraction of the soil upon the water 

 which it holds, a considerable height of column to give the weight 

 necessary to force that attraction being required. 



(-'). The frequency of drains must be greater according to the 

 greater quantity of water falling in a given time as nun, to which the 

 climate exposes the land to be drained, and according to the difficulty 

 of percolation which the laud presents. In practice the quantity of 

 exit provided in the least efficient drainage is sufficient for i 

 inoval of the largest probable rain-fall. The size of the pipes is deter- 

 mined by other considerations than the quantity of water t 

 deliver a larger pipe is rendered desirable by the fact that when a 

 smaller one is used a very slight displacement breaks the continuity of 

 the pipe. 



The interval between drains is to be determined by the rain-fall 

 and the capability of percolation. The depth of drains should be 

 allowed very little influence on the interval The direction of drains 

 should be right down the slope, simply because when once the water 

 gets into them, the shortest way out of the field is the best. 



(3). The arrangement of the drains at varying intervals is necessary 

 :nes, to suit the varying distribution by which rain-water is 

 accumulated in certain spots, so that springs and swamps are pro- 

 duced. 



As a general rule, however, drains as nearly 4 feet deep as 'may be, 

 and from 5 to 10 yards apart, greater according to the porosity of 

 soil and subsoil, should be laid parallel to one another, and for the 

 most part straight down the slope. The material used should be the 

 common cylindrical pipe tile, about 2 inches in the bore, less than 

 this at the upper part of the drain, more in the lower. 



In commencing drainage, prepare a general plan for the farm or 

 estate. Seek, in the first place, by straightening water-courses and 

 draining springs, to give rapid exit for all tin comes into 



the land otherwise than from the clouds. In the after drainage of the 

 land the general rule is to commence the drainage of the lowest part 

 first, attending to the final outfall first of all. There are exceptional 

 cases where the drainage of a higher land may to some extent remove 

 water at once which fed the lower grounds. When spring 



'1, drain o deep (to 4 feet) as the outfall will permit, and with 

 such attention to uniformity i-f interval as the adhesiveness or poro- 



