WATER-RELATION BETWEEN PLANT AND SOIL. 



33 



affairs is in agreement with what might be expected from the seasonal 

 difference between the two periods. There appears to be nothing remark- 

 able about the behavior of this rate for either day; these graphs are 

 fairly representative of the conditions obtaining in a rather dry green- 

 house, on sunny days when some artificial heat is applied. 



ABSORBING POWER OF THE SOIL (/). 



For the February period the maximum (4.72) occurred with hour 16, 

 but nearly as high a rate was maintained till hour 18. The low night 

 rate was not here attained till hour 23, but it was maintained from hour 



COLEUS 



FEB. 23-24 



MAR. 23-24- -= 



ENVIRONMENTAL ARIDITV, I X 



RELATIVE TRANSPIRATION 



ABSOLUTE TRANSPIRATION 



IRRIQATOR LOSS. I 



EVAPORATION, E 



5 6 7 8 9 



|Q'||'I2'I3 14 I5'I6'|7'I8'I9'20'2I'2Z'23'24' I ' 2 

 FIG. 1. Graphs for Coleus. 



