142 



IRRIGATION. 



rectly or diagonally down the slope. The furrows branch 

 both to the right and left from the feeders, and have but 

 very little inclination from the level. They are made to 

 diminish in size from the feeder until each disappears in a 

 point at the extremity. Each feeder with its two lateral 

 ranges of furrows thus appears upon the surface in shape 

 like the backbone of a fish, or what is especially known 

 as &quot;herring-bone shape.&quot; Fig. 70 exhibits a plan of a 

 meadow thus laid out. The slope of the field is from 

 top to bottom. The water is received by a main canal, 



_-=== A 



B &quot;~ **** 



Fig. 70. FURROWS AND DRAINS FOR IRREGULAR BLOPES. 



and is diverted into subsidiary canals, A, B, and from 

 them into the feeders, a, a, a, and the furrows which 

 branch from them upon each side. The drains are seen 

 at , , #. The course of the water is shown by the ar 

 rows. The distance between the feeders should be from 

 100 to 150 feet, which will make the furrows from 50 to 

 75 feet long, and the latter should be from 15 to 20 feet 

 apart. These distances will be regulated by the character 

 of the soil as to its porosity or retentiveness. The lower 



