RESEARCH METHODS IX STUDY OF FOREST ENVIRONMENT. 163 



evaporating surface, and the probable correction due to these fail- 

 ures of the instrument should in all cases be estimated and entered 

 in the " Corrections " column of the field form "Daily Observations." 

 Interpolations of this character should be indicated by asterisks on 

 the "Humidity, Wind, and Evaporation" form. 



TABULATION". 



The tabulation of evaporation data on the "Humidity, Wind, and 

 Evaporation' form consists in setting down all of the recorded 

 weights of the evaporimeters, or graduate readings, and the losses 

 computed therefrom. In the record for porous cup atmometers, 

 there will usually be but one entry for each observation, though 

 these instruments may also be handled on a weight basis more satis- 

 factorily than on a volume basis. The corrections for calibration 

 are made usually on the sums for 10-day periods. 



Form Z 



Daily observation at 



Date or month 



