THE TEMPERATURE OF THE BEE COLONY 



13 



15, when the outside thermometer reached 22.6° C. (72.68° F.). In 

 all the other winter months there were days when the thermometers 

 registered only 2 or 4 degrees less. 



In conclusion it may be said that throughout the season the tem- 

 perature below the frame was practically the same as that of the out- 

 side air. Of special significance is the fact that the daily extremes, 

 the maxima and minima, no matter what were the variations at other 

 periods of the day, were usually identical. From these observations 



Fig. 



.—Curves showing relation of temperature of center of bee cluster to outer temperature, Feb. 



1 to 10. 



it would appear that the contraction of the entrance and the tight 

 bottom board were not of much service in protecting the colony from 

 cold. Colonies without bottom boards have frequently been known 

 to survive extreme winter cold. It may be, however, an advantage 

 to a colony to be protected from the sweep of violent winds; but 

 there is no evidence that this colony appreciably warmed the lower 

 part of the hive in which it was wintering. Under such conditions 

 the bottom of the cluster is bathed in an atmosphere of the same 

 temperature as the outside. 



