CHAPTER V. 

 WATER-SUPPLY. 



t" l¥ N CALCULATING on engaging in an irrigation 

 1^ enterprise of any kind it is well to remember 

 ^^Bl that we must first catch our rabbit before we 

 can cook the stew. No one should attempt 

 irrigation without first having determined the extent 

 and continuity of the water-supply, and where a vast 

 amount of money will be needful in carrying out the 

 enterprise, as in the construcftion of large works, the 

 services of a pracftical hydraulic engineer should be 

 secured by all means, and his report should be rendered 

 before entering upon the scheme. To get at the 

 source of all water-supply, we must accept the well- 

 recognized scientific fadl that the waters upon the 

 earth and the clouds in the air are forever in recipro- 

 cal motion. The waters are lifted and ascend into the 

 heavens, the clouds are drifted away over the land and 

 discharge their moisture upon the land, and life is 

 supported thereby. The amount of water which is 

 taken'out of the ocean by evaporation each year is very 

 great. About thirty-five or thirty-six inches of water 

 rise by evaporation from the surface of the earth 

 annually. This rainfall on the entire earth would 

 make a sheet as large as the surface of the earth and 

 about three feet in depth. It would fill I^ake Superior 

 six times every year. 



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