84 THE STUDY OF PLANT COMMUNITIES • Chapter V 



DRY BULB TEMP. V. R D. WET BULB TEMP. 



(C°3 (mm. Hg.) ( C °) 



r~40 -, 



- 35 



- 30_ 



-20 



-25_ 



40 



-35 



-2 5 



-15- 



_I0_ 



- 5 _I 



L J 



30 



-20_ 



-I 5_ 



- 10- 



- 5 1 



t-OJ 



T-70 



__60 



_^50 



__40 



__30 



_:l20 



:_IO 



-i. 



r— — i 



- 5 - 



- I 0- 



-I 5_ 



-20_ 



-25 



-i 



- 5 - 



-10- 



-15- 



-20- 



30 



COPYRIGHT 194 

 W. E. Gordon 



35 



B* 



!0 



40 





25 



30- 



-35 











.^40 J 





Bo romet e r So romerer 



FlG. 33. Nomogram for the direct conversion of wet and dry bulb tem- 

 peratures to vapor pressure deficit, at barometric pressures of 30, 29, 27, and 

 25 inches. To use, lay a straight edge across the appropriate temperature 

 values on the wet and dry bulb scales and read off VP.D. directly. Because of 

 the reduction necessary for this reproduction, extreme accuracy is not pos- 

 sible in its use— By permission W. E. Gordon. 108 



