DRIVEN MACHINES 



113 



natural or artificial, carries off the excess. Irrigation 

 and drainage belong together. Irrigation fills the soil 

 with moisture and drainage empties it. Thus, a con- 

 dition is established that supplies valuable farm plants 

 with both air and moisture. In the drier portions of 

 the United States, nothing of value will grow without 



Figure 126. Centrifugal Pump Setting. When used for irriga- 

 tion, centrifugal pumps are set as close to the ground water as 

 practical. 



irrigation. In the so-called humid districts deficiency 

 of moisture at the critical time reduces the yield and 

 destroys the profit. The value of irrigation has been 

 demonstrated in the West, and the practice is working 

 eastward. 



Irrigation is the new handmaiden of prosperity. A 

 rainy season is a bountiful one. Irrigation supplies 

 the bounty without encouraging destructive fungus 



