CLIMA TIC CHANGES IN THE PRAIRIE REGION. 301 



are now only covered with grass, that in its entirety it is not condemned for all 

 time to a mere pasturage. The plains are not sterile as was and is believed by 

 many to-day. Their proportion of unproductive land in consequence of inac- 

 cessible bluffs or rocky mesas is less than in any other equal area on the globe. 

 Portions of the far-off plains are only comparatively arid ; with precipitated 

 moisture in sufficient measure — which will in time come — or water through the 

 medium of irrigation, the richest agricultural results are assured. That the 

 whole of the vast interior area of the continent will become habitable as rapidly 

 as the demands of civilization require, we should have no doubt. When the 

 limit of sufficient precipitated moisture is reached, or where the timber will not 

 grow spontaneously — for that will be the line of demarcation — but which has not 

 yet been determined — then the available streams and rivers of the region must be 

 used for irrigation. 



The remarkable excess in inches of the spring and summer rains over those 

 of autumn and winter, and which have persistently increased in measure as civili- 

 zation pushes towards the mountains, have permitted thousands of farms to be 

 opened far beyond the ninety-eighth meridian, whose productiveness in corn, 

 wheat and other cereals have astonished the world, justifies the assertion that the 

 limit where a sufficiency of aqueous precipitation ceases, and irrigation must be 

 depended upon, is not yet reached. Whether that will be attained until the 

 actual slopes of the mountains are compressed, as is confidently believed by 

 some, cannot yet be determined. The writer does not accept that theory fully, 

 on account of apparently dominant adversely controlling forces in the immediate 

 locality of lofty ranges, though he does not deny the possibility of the truth of 

 the theory. 



At the foot of the mountain slopes the streams have already been utilized 

 for the purpose of irrigation most successfully, flowing as they do in so many 

 pleasant lines from the rainy and snowy heights of the Rocky range, and this 

 system of cultivation will spread eastward to meet the progress of civilization that 

 is rapidly moving westward until the lines of sufficient precipitation meet those 

 of irrigation, and the hiatus now existing between the advancing armies of per- 

 manent occupation is closed. 



To many who have not studied the changes that are taking place on the 

 great plains, it probably seems a curious and presumptive proposition that they 

 are destined to become the principal food-producing regions of the Continent — 

 perhaps, of the world — but the idea will not appear so unwarrantable when we 

 reflect how rapidly their agricultural proclivities are being developed and that the 

 theories of the laboratory and the speculations of the professor's study in relation 

 to them are sadly in opposition to the truth ; facts are answering the problems of 

 that region with more effect than philosophy. 



It makes no difference in the solution of the proposition, that the whole inte- 

 rior portion of the United States under consideration will be made habitable, 

 whether the necessary changes which are to effect the result are slow or rapid; it 

 is an established fact, however, that as civilization reaches out into the wilderness 



