Like Rainfalls not Equally Productive 103 



compare the yields of barley, oats, rye and wheat in 

 the three districts, taking the Tenth Census figures for 

 California, Washington and Kansas for comparison, 

 the yields are largest in Washington and smallest in 

 Kansas, as shown below: 



< Mean yield per acre of > 



Barley Oats Rye Wheat 



Washington 38 41 14 23 



California 21 26.8 9 16.1 



Kansas 12.5 19 12 9.3 



Expressing these differences in percentages, we get: 



Washington 100 100 100 100 



California 55.2 65.3 64.3 70 



Kansas 32.9 46.3 85.7 40.4 



As the soils in the three regions are notably fertile, 

 and were in 1879 very .close, on the average, to virgin 

 conditions, the differences in yield can hardly be attrib- 

 uted to differences in plant -food other than as influenced 

 by soil moisture ; and as the quantity of rain which falls 

 in Kansas during the growing season, April to Septem- 

 ber, inclusive, is 11.5 to 16.8 inches, while that in 

 Washington is only 8.4 to 13.5 inches, it appears plain 

 that in some way the available moisture is more effective 

 on the Pacific border than it is in the 97th meridian 

 region. 



It would be of very great practical importance to 

 understand fully the causes which permit so small an 

 amount of rain as that of eastern Washington, falling, 

 so much of it, before the growing season, to ensure the 



