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[Senate 



Fig. 



Fig. 3. 



Modes of Practice. 



The simplest mode is represented in fig. 1, where A. B. is the 

 stream to be used, running in the bottom of a valley. From this 

 stream the water is conducted in channels on each side, as high up 

 the sides of the valley as a moderate current in those channels will 

 admit, and from these the water is made to escape through holes in 

 small pieces of boards, placed at regular intervals, so as to spread 

 the water over the surface below. If the sides of the valley are 

 steep, the angles w^hich these channels will form with the main 

 stream will be acute, that is, it will be necessary to conduct them to 

 a considerable distance down the valley, in order to recede much 

 from the main stream. Where, however, the land is more nearly 

 level, they W'ill diverge from the stream more nearly at right angles. 



Where, however, the land lies very nearly on a level, it becomes 

 necessary to guard against the stagnation of the water upon the sur- 

 face. This object is accomplished by means of the mode represented 

 in fig. 2, where the channel C carries the water from the main stream, 

 and from which again the smaller channels c c c c, conduct the water 

 more evenly over the surface. To prevent the water standing on the 

 ground, small drains d d d d, are made between the channels and 

 alternating with them, which convey the water to the main drain D, 

 through which it again empties into the stream. 



When land subjected to irrigation is nearly level, it should be 

 plowed into " lands" in such a manner that the channels for distri- 

 buting the water, as in fig. 2, may be upon the ridges, and the drains 



