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the eastern side must be the plough, advancing westward from 

 the humid areas. I think there is now no question but that the 

 steady advance of agriculture toward the southwest, in Kansas, 

 during the past ten years, has projected the rain belt in the same 

 directions. 



" Under the old conditions of prairie sod the rainfall found 

 an immediate passage into the drainage channels, leaving little 

 or nothing to be returned to the atmosphere. Under the new 

 conditions of the pulverization the soil is converted into an 

 ^mense surface reservoir for the retention of the rainfall. I 

 believe that this problem of tempering the western winds with 

 moisture will, in time, be solved by the exigencies of our civili- 

 zation by systematic field and forest culture, but it can be hast- 

 ened by intelligent inter-state action. Let me show you what pri- 

 vate enterprise is doing in Colorado, and I wish you to note its 

 rationale : A company has tapped the Platte river in the Platte 

 river canyon and by boring through a mountain brings the 

 stream out on a high plateau of arable lands. The supply 

 canal for these lands is about 80 miles long and is calcu- 

 lated to furnish water for 200,000 acres of ground. Under 

 the old condition the surface of the Platte exposed for evapor- 

 ation for this distance was not much over three square miles. 

 This plan gives it an evaporating surface equal to nearly 200 

 miles. But we must measure its evaporating capacity by the 

 area of the land that is irrigated. 



A more just approximation would be reached by calculating 

 the combined superfices of the leafage that the land sustains. 

 The plant roots appropriate the water, and the leaves give it to 

 the air around them. So tljat we see in this the fact that an 

 irrigating ditch not only waters the ground, but practically 

 pours that same water indirectly into the atmosphere if that 

 ground be cultivated. It will readily be seen how every enter- 

 prise of this kind brings about a modifying influence, tending to 

 laden the atmosphere with vapor. The facilities for extending 

 this work are as yet barely comprehended. 



Of one thing we may rest assured, the future of those states 



