Jan. 3, 19x6 
Hourly Transpiration Rate on Clear Days 
601 
The sorghum measurements were made during the latter part and the 
oat measurements during the first part of August. The amplitude and 
spread of the radiation curves for the two periods are essentially the same 
(see figs. 4 and 5). The air temperature during the sorghum period was, 
however, much higher, the average daily maximum being over 9i°F., 
Fig. 5.—Composite transpiration graph of sorghum, with environmental graphs for corresponding period. 
compared with a maximum of 79 0 during the oat period. There is also 
a corresponding difference in the wet-bulb depression, the mean maximum 
depression during the sorghum period being over 26°, compared with 17 0 
during the oat period. The conditions were consequently more severe 
during the sorghum period—i. e., such as to induce a higher transpira¬ 
tion rate. Yet it will be seen, on reference to the transpiration graph 
