258 



G. A. PEARSON 



TABLE 3 

 Evaporation, wind and relative humidity 



spring season the soil in both situations was thoroughly saturated. 

 By June 21, owing to heavier water loss, the moisture content 

 in the open had been reduced considerably below that in the 

 aspen thickets. The July and August determinations, however, 

 show the reverse relation. This is principally due to the fact 

 that in the aspen stands a considerable portion of the rain was 

 intercepted by the foliage or absorbed by the dry leaf litter on 

 the ground, while in the open it went directly into the soil. In 

 a season of heavy rainfall there would be more run-off in the 

 open than in the aspen, but since the summer of 1912 was an 

 exceptionally dry one the run-off was not great. By September 



