12 BULLETIX 951, U. S. DEPARTMEXT OF AGEICULTUEE. 
being located near the top and in the center of the room. The charts 
taken from the recorders are examined and any variations in tem- 
perature beyond the prescribed limits are noted with the time at 
Tvhich the variations occurred. AYith these data at hand it is nearly 
always possible to find the cause of an excessive variation in tem- 
FiG. 9. — The temperature-conu'ol boards used by the Bioeliomic Division. 
perature and also to fix the responsibility, if any is due. The mere 
fact that a permanent, continuous, and exact record is kept of the 
temperature conditions inside the incubator room is a stimulus to 
those in charge to do their best to maintain the conditions desired. 
