Effect of Climate and Soil upon Agriculture 19 
A clearer understanding of what constitutes a profitable farm business 
west of the line of critical moisture will in time do away with much of 
the element of risk now entering into loans made on western land. 
Observe the relation which lines on this map bear to lines indicated on 
the following maps. 
Fic. 23. The distribution of telephone lines is affected by critical mois- 
ture and critical temperature. Compare the figures with Figs. 22, 24, 25. 
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Fic. 24. North Central States divided into four areas according to type 
of farming. Division made by the Office of Farm Management, Wash- 
ington, D. C., in recent fence investigations. (U.S. Dept. of Agriculture 
Bulletin 321.) Compare this figure with Figs. 22, 23 and 25. 
109 
