THE OX AND THE DAIRY. 165 



strata may be found by boring, into which it can be made to 

 run and be dispersed. Along rivers where the fall is very 

 imperceptible, a channel brought from a considerable distance 

 may give such a command as to throw the water over a great 

 extent of surface ; and, to carry it off, another channel may be 

 cut, emptying itself at some distance below : thus lands which 

 lie along the banks of a river may be irrigated, although they 

 are actually below the level of the river, and require banks to 

 protect them from inundation. 



When the surface to be irrigated is very flat and nearly 

 level, it is necessary to form artificial slopes for the water to 

 run over. The whole of the ground is laid in broad beds 

 undulating like the waves of the sea. The upper part of these 

 beds is quite level from end to end, and here the channel or 

 float which brings the water on is cut. From the edge of this 

 channel the ground is made to slope a foot or two on both 

 sides, and a ditch is cut at the bottom parallel to the float. 

 The whole of the ground is laid out in these beds. All the 

 floats are supplied by a main channel at right angles to the 

 beds, and somewhat above them, and all the ditches or drains 

 run into a main ditch parallel to the main float, and below 

 the lowest drain. The course of the water is very regular. 

 As soon as the flood-gates are opened it flows into a'l the 

 upper channels, which it fills till they overflow in their wLcle 

 length. The sloping sides are covered with a thin sheet of 

 running water, which the lower drains collect and carry into 

 the main ditch. 



Experience has shown that there are particular seasons 

 when the water has the best effect ; a perfect command of it 

 is therefore indispensable, and also a regular supply. During 

 frost, when all dry meadows are in a state of torpor, and the 

 vegetation is suspended, the water-meadows, having a current 

 of water continually flowing over them, are protected from the 

 effect of frost, and the grass will continue to grow as long as 

 the water flows over it. Too much moisture however would 

 be injurious, and the meadows are therefore laid dry by shut- 

 ting the flood-gates, whenever the temperature of the air is 

 above freezing. By this management the grass grows rapidly 

 at the first sign of spring. Before the dry upland meadows 

 have recovered the effects of frost and begun to vegetate, the 

 herbage of the water-meadows is already luxuriant. As soon 

 as they are fed off or cut for the first crop of hay, the water is 

 immediately put on again, but for a shorter time. A renewed 



