LIST OF ILLUSTRATIONS 
Jethro Tull . 2 ‘ 3 ‘ ‘ r - - Frontispiece 
NO. PAGE 
1. Utah sagebrush land . . . i: é F 2 
2. Native sod of Rocky Mountain foothills ki ‘ 5 F 3 
3. New Mexico dry-farm lands . 5 5 F , 7 0 6 
4. Land above the canal . . F . . . 9 
5. Weighing pots in transpiration expedimanie. P ‘ » 18 
6. Plant house for transpiration experiments . F 15 
7. The quantity of water required for the production of dvs 
matter . . a 3 . 18 
8. The rolling hills of the ‘iaiicae went district 7 P . 19 
9. Rainfall chart for the United States. . re . 28 
10. Sagebrush under ten inches rainfall . s : . » 25 
11. Sagebrush under fifteen inches rainfall . ‘ is ‘i - 27 
12, Rainfall chart for the world . é . ‘ 30, 31 
13. Physical features of the dry-farm terstory of the United 
States . 2 37 
14. Chart showing the distribution of sednfatl in the wrest 
United States . ‘ ‘ - : : . 42 
15. Sagebrush land covered wath snow . ° . - . 48 
16. Sunshine in Canada and the United States . a F a AT 
17. Soil structure : A . F . 56 
18. Difference between amid anil nid soils ‘ ‘ ‘ » 68 
19. Deep soil, suitable for dry-farming s - ‘ ‘ . 67 
20. Gravelly soil, not adapted for dry-farming . 5 ‘ » 72 
21. Soilaugers . ‘ P 6 : A s : . 79 
22, Wheat roots . . . . F . . . . . 82 
23. Alfalfa roots. F é 3 $ . . : ‘ . 88 
24. Sugar-beet roots . ; . j eT z . . 87 
25. Cornroots . 3 P 3 . 89 
26. Root systems under egal andl ard conditions . . . 91 
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