THE VEGETATION OF MONTAUK 



69 



ment* may or may not coincide with the greatest possible sunshine, while 

 it nearly always does with high wind. 



Figure 24. Montauk atmometer readings, 1921. Upper series are on the open 

 Downs, lower in the shade of wooded kettlehole. Black lines = black instruments, dotted 

 lines = white instruments. The records are reduced to the cc. of evaporation per day, 



* And also from the white instruments. But the blacks show much greater excess 

 of evaporation over the whites during high winds than at other times. The basis of the 

 argument in a nut shell is that black instruments reflect transpiration rates better than white 

 ones, and if this is true, as Bates and Burns would have us believe, then high wind move- 

 ment, as reflected by the meteoric rise of the black instrument, does so affect transpiration 

 as to be one of the chief limiting factors. 



