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MONTHLY JOURNAL OF AGRICULTURE. 



other portions of the world in this particular ? We do not lack proofs, sufficient 

 to every observing mind, even in the rough and wild manner in which it is per- 

 formed by the inundation of the flats of creeks and rivers, nor has such proof 

 been wanting, from the overflowing of the JS'ile in ancient days down to the 

 present age of the world ; but the artificial process possesses this eminent ad- 

 vantage, that while the former is uncontrollable and uncontrolled, the latter may 

 be applied or withheld at pleasure, as the crop sufi'ers from drouth, or becomes 

 injured by too heavy a flooding. 



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 which 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 will di- 

 verge 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 surface. 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 distributing the water, as in 

 fig. 2, may be upon the ridges, and the drains in the dead furrows. This is 

 shown by the section represented by fig. 3, c c c c, being the distributing chan- 

 nels, and d d d, the drains. 



Laying out the Channels. — This can never be done with sufficient accu- 

 racy without a leveling instrument. The cheapest for this purpose is repre- 

 sented by fig. 4. It consists of the two legs AB and AC, which should be 

 light, but not less than ten leet Ions, connected and stillened by the cross bar, 

 the two ends of which must be exactly equidistant from the point A. A plumb 

 line is suspended from the summit A, and if the legs stand on level ground, 

 the line will cut the cross bar exactly in the middle : but if the point of one 

 leg be lower than the other, the line will fall out of the center and toward. 



(300) 



