PERMANENT CORRECTIONS 



If a useless pond of water can be drained easily, 

 which is often the case, it is a foolish waste of time, 

 energy, and money to repeatedly oil it. Marsh}' land, 

 otherwise useless for agricultural purposes, can in most 



Fig. 27. A big pond alongside the railroad caused by obstructing the natural drainage. 

 This was a source of many mosquitoes every year. The Field Agent is oiling the pond. 

 A source of constant danger, requiring repeated expenditure of time, labor, and money 

 until permanently corrected. 



cases be made useful and also free from mosquitoes 

 by digging a ditch of necessary depth with connecting 

 laterals. The dry summers of California, for example, 

 favor permanent corrective work, because areas from 

 which standing water is drained off at the termination 

 of the rains in spring will remain dry for the rest of the 



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