270 



SMITH 



Average = 10- 7 

 So far the figures show the young leaf decidedly cooler than 

 the mature. The conditions, though similar, are not exactly 

 the same, as will be seen by comparing the readings of the 

 black bulb thermometer and the humidity in the two cases. 



An attempt was made to get readings under more closely 

 comparable conditions in the following way. Thermo- junctions 

 were placed in two leaves, one, young, the other mature, and a 

 reading was taken of one of them. This with its junction was 

 then taken out, and the other one put in its place and a reading 

 taken. Thus, the readings followed one another pretty closely, 

 only the time required to replace one leaf by the other inter- 

 vening between. This method gave the following results : — 



Table XXXIV.— November 16, 1906. 

 Amherstia nobilis. 



This series, especially in the later readings, shows that the 

 two kinds of leaves were nearly equal in temperature. The 



