that of increased friction and loss of velocity. This is a more serious matter than might be supposed, especially in a main drain; for if several branches deliver into it, and the main has more velocity than the branches, it is evident that, in that proportion, can a smaller pipe be used to convey the same amount of water. In consequence, we lessen the cost of the material, as well as increase the efficiency of the work. The sole-tile is

the best. If laid on strips of board it is more efficient, and in the hands of a skilful workman becomes an excellent drain. A square of turf, strips of waste tin, or, what is better than either, tarred paper, should be placed over the joints to keep out the sand. Many have supposed that the water entered mostly through the substance of the tile. Although this is true to some extent, yet the principal quantity runs in at the joints, and therefore it is necessary that they should be defended from the loose sand which often accompanies it.

We suffix a table from the " Farm Drainage."

TABLE H.-SHOWING THE COST OF Sole-Tile of different Sizes.

TABLE I.-SHOWING THE NUMBER OF CUBIC YARDS OF EARTH IN EACH ROD IN LENGTH IN DRAINS OF VARIOUS DIMENSIONS.

Inches. 7 in. 8 in. 9 in. 10 in. 11 in. 12 in. 13 in. 14 in. 15 in. 16 in. 17 in. 18 in.

TABLE J.-SHOWING THE NUMBER OF TILES NECESSARY PER ACRE TO LAY DRAINS AT DIFFERENT INTERVALS.

TABLE K.-SHOWING THE NUMBER OF RODS PER ACRE OF DRAINS AT DIF

6. Manner of laying the tile and completing the drain. Beginning at the outlet, the trench can, of course, be dug as narrow as possible, only allowing space enough for the workman to place the tile. The pipes should then be laid along the bank. If turf is to be used for covering the joints, it should be cut, and immediately at hand. The size of the pipes for the mains must be determined by the number of minors and the amount of water to be conveyed. Generally one of four or five inches is sufficient; but when it is not, two ean be placed abreast, or one more above them. The workman, walking backwards, should commence to lay the pipe carefully, securing a continuous channel, and preserving the proper grade by the use of the line. The joints are secured as the work goes on, and the earth carefully shovelled in, and trodden down as hard as possible, to prevent the washing of the sand. Where the minors join the main, the junction must not be too abrupt, but should turn gradually, and enter it upon a curve, that neither may be obstructed by the meeting of the currents.

There are many places where it is impossible to find an outlet. If wells in the vicinity do not rise to less than twelve or fifteen feet from the surface, such tracts can be drained by digging dry wells, and turning the water into them.

It is very convenient to construct traps in the orchard when draining. These are formed by

THE EFFECT OF DRAINING.

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sinking a hogshead, or, more permanently, by building a small reservoir of brick or stone. The drain above leads into it, and the one below takes off the surplus water. These are very convenient for use in the orchard, and in furnishing the workmen with cool water. They are also interesting, as they show the operation of the drains.

7. The discovery of obstructions. All drains will sometimes become stopped, either by some animal which has taken refuge in the pipe, or by sediment. When such is the case, and the ground is wet, the point can generally be detected by the external appearance of the land. On a slope, the water will often burst forth upon the surface. When this does appear, the tile must be taken up at the obstructed part and cleaned. Over drains from which there is a continual flow of water, no crop should be planted whose roots will be attracted by it so as to fill up and choke the pipe; but there is no danger of this over those whose flow is confined to the wet season, and after heavy rains.

We have now considered the sources of moisture in the soil, and the means of removing it, and thus are prepared to notice the effect produced.

It promotes pulverization. The comminution of the soil is of great importance, as it permits the free entrance of the air among its particles. Indeed, of so much value is this pulverization of the ground,

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VENTILATION OF THE SOIL.

that a system of cultivation was based upon it, and the effects were remarkable, even without the addition of the least manure. Before drainage has taken place, this is impossible, as the ground is so wet that the more it is worked the closer it becomes; but when it is dry it crumbles in handling.

The prevention of injury from drought, which we have already commented upon, is another benefit which arises from draining.

The power of absorbing moisture. The dry and friable soil is better prepared to drink in the dews of the night, and thus is partially compensated for what it has lost during the day by evaporation. This is a potent source of fertility, for the air is freighted with fertilizing gases, which the soil imbibes with the water.

The ventilation of the soil is also accomplished by drainage. The earth contains substances which require the oxygen of the atmosphere to decompose and prepare them to become the food of plants. While the soil is filled with stagnant water, decomposition is arrested; but when the air takes its place, it progresses rapidly. This decomposition is slow combustion, and therefore generates heat, which increases the warmth of the earth in the spring, at which time it is so desirable.

It permits the warm, early showers to enter the soil and aid decomposition, by augmenting the heat of the ground.