78 



IRRIGATION FARMING. 



also has a steel or iron rod one and one-fourth inches in 

 diameter passing through the center, with ends pro- 

 jecting and resting in the boxing. The levers 3 and 4 

 are bolted to the main axle. 

 Between levers 4 is placed and 

 fastened with bolts a set of X 

 braces to prevent the levers from 

 becoming displaced by wind or 

 other causes, thus making the 

 strucfture firm and rigid. 



Ditch Outlets.— The outlets 

 or culverts through the canal 

 banks to the main lateral should 

 be set before the bank is built 

 and with reference to the supply 

 laterals. The size of the outlet 

 will be governed by the amount 

 of water to be delivered to the 

 lateral. The outlets may be made 

 of plank or vitrified sewer pipe, 

 the latter being especially good 

 but in most cases not so readily 

 obtainable. The earth should be 

 well tamped about the box or 

 pipe in order to make a water- 

 tight joint. 



Regarding gates, these should 

 be set at the inner end of the out- 

 lets, and a plank wall built from 

 the top of the bank leading out 

 over the water to a point over 

 the gate, in order that the gate 



FIG. 17. 



IRON OUTLET GATE. 



