134 



DRY-FARMING 



Temperature 



Fahrenheit 

 ( Degrees) 



Weight of Water Vapor 



that can he held in 



One Cubic Foot of Air 



(In Grains) 



Difference 





 32 



40 



60 



60 



70 



80 



90 



100 



0.545 

 2.126 



2.862 



4.089 



5.756 



7.992 



10.949 



14.810 



19.790 



0.736 

 1.227 

 1.667 

 2.236 

 2.957 

 3.861 

 4.980 



water during the fall and winter when the tempera- 

 ture is li>w and the moisture usually abundant, and 

 the greater difficulty of storing the rain that falls 

 largely, as in the Great Plains area, in the summer, 

 when water-dissijmting forces are very active. This 

 law also emphasizes the truth that it is in times of 

 warm weather that every ]5recaution must be taken 

 to prevent the evaporation of water from the soil 

 surface. 



It is of course well understood that the atmos- 

 phere as a whole is never saturated with water vapor. 



