PLATE LIU 
General view of the water requirement and transpiration experiments at Akron, 
Colo., on July 8, 1913. The large, screened inclosure in which the transpiration 
measurements were made in 1912 is shown at the right. The small instrument shelter 
in the foreground contained differential thermographs for measuring wet-bulb depres¬ 
sion and solar radiation. The glass envelope surrounding the bulb of the radiation 
instrument may be seen on the top of the instrument shelter. At the left in the 
foreground is shown balance A, the front of the box open, and the recording device 
uncovered at the left. This balance is carrying a pot of sunflower. The next balance, 
B, carries the evaporation tank; balance C, another sunflower pot; and balance D, 
under the shade at the left, a third sunflower pot. The exposure of balances A and 
B, as used in the 1913 and 1914 determinations, is shown in this illustration. 
(650) 
