PLATE i 
A. —Climatic chambers in operation. 
a. Water supply to humidifier. 
b. Heating units of humidifier. 
c. Mercury thermostat of humidifier. 
d. Bimetallic thermostat of culture chamber. 
e. Atmometer on rotating table. 
f. Hygrograph and thermograph on rotating table. 
g. Air conduit with gate. 
h. Motor and reducing gears belted to rotating tables. 
i. Electric lamps. 
B. —Humidifier. 
a. Asbestos blanket. 
b. Toweling, showing brass clips in tray above. 
c. Concentric cylinder to contain heating units for water supply. 
d. Fan supplying air. 
e. Front flanges directing air current. 
f. Escape to drain. 
