NATIONAL, ACADEMY BIOGRAPHICAL MEMOIRS VOL. VIII 



areas are permanent assets of immense value to the West, and 

 much profit now comes from many similar but smaller areas ; 

 but even the greenest spots in the most barren wilderness were 

 always called settlements, and never oases. In various parts 

 of the arid region the latter name would have been quite as 

 appropriate as it is in the Sahara, but its connotation of a 

 surrounding desert was too manifest to make it acceptable. 

 \ "Powell told the truth about the dry country, and advocated 

 a comprehensive plan whereby its real values might be devel- 

 oped. It was at his suggestion that Congress appointed a 

 commission to study the physical and economic conditions of 

 the arid region, and he gave two years to this work. We have 

 no narrative of his Western journeys in this connection, but 

 the results were published in a most important "Report on the 

 Lands of the Arid Regions of the United States" in 1879, to 

 which Gilbert, Dutton, and Thompson contributed chapters. 

 Few reports have had a greater value in "pointing out the direc- 

 tion of safe and sound progress. The first edition of 1,800 

 copies was soon exhausted, and a second edition of 5,000 was 

 issued. The area treated was about four-tenths of that of the 

 United States, and the report was the first comprehensive 

 study of the kind issued in this country; today it is recognized 

 as a classic treatise on the subject. 



Powell cautiously set the limit of successful agriculture 

 without irrigation the singular art of dry farming was then 

 unknown at the line of 20 inches of average annual rainfall, 

 and showed the danger that farming must run from frequent 

 droughts east of this line in that belt of the Great Plains 

 trending north and south, which lies between the rainfall lines 

 of 20 and 28 inches and which he first called "subarid;" but 

 the name "subarid" was later, on suggestions received in 

 Washington, changed to "subhumid" as a less unpleasant 

 term. He recognized an increasing stream supply during a 

 decade previous to the preparation of his report; but, instead 

 of explaining it, as many have done, by an increase of rainfall, 

 he ascribed it to an increased "run-off" due to artificial changes 

 in the land surface. It may be noted, in passing, that the term 

 "run-off," now in general use, was invented by Powell; his 

 correlated term "fly-off," for rainfall that is lost by evapora- 



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