THE PHYSICAL PEOPEETIES OF SOILS 



69 



38 inches, over 60 per cent, escaped in the drainage, but in 

 1898, when the rainfall was just over 20 inches, only about 

 35 per cent, escaped in the drainage. 



Evaporation. During the six winter months October 

 to March the total rainfall amounted to 14*7 inches, and 

 during the six summer months April to September it 

 was 14'28 inches, or very nearly the same. The amount 

 of drainage during these two periods was, however, very 

 different, being 10*09 inches during the winter and only 

 3'81 inches in the summer. The difference is due to the 

 greater amount of evaporation which takes place during 

 the warm summer weather. 



The following table shows the average monthly evapora- 

 tion, i.e., the difference between the rainfall and the 

 drainage : 



MONTHLY KAINFALL AND EVAPORATION FROM BARE SOIL AT 

 EOTHAMSTED. 



Average of 34 years, 18711904. 



