THE TEMPERATURE OF THE BEE COLONY. 21 



for weeks at a time, this phase of the experiment could not be carried 

 out. 



RELATION OF C TO THE OUTSIDE TEMPERATURE. 



Whatever is said of c in the following paragraphs applies equally to 

 b, and practically as well to all the thermometers in the hive. 



Although the temperature at c coursed constantly in the opposite 

 direction to o during the winter, there is no appreciable correlation 

 between the temperatures in the summer. It might be said of the 

 hive that the temperature as a whole was independent of external 

 conditions. A few exceptions to this will follow, however. During 

 a period of stormy and cooler weather, for instance, although there 

 were slight changes which will be discussed later, the temperatures 

 were largely unaffected. Moreover, since the oscillation of c was 

 slight, as will be explained, there was little relationship between the 

 temperature of the center of the cluster and o. 



THE MAXIMA AND MINIMA OF C IN RELATION TO O. 



The daily oscillation between the maximum and minimum of c 

 was usually less than 1° C. (1.8° F.), and in many instances it was but 

 one or two tenths of a degree. On the whole the temperature in the 

 brood nest is remarkably constant, ranging between 34° and 35° O 

 (93.2° to 95° F.). 



Even with this slight fluctuation there was perceptible on many 

 days a maximum and minimum for c, and particularly for the other 

 hive thermometers which perhaps were the most influenced by ex- 

 ternal conditions. It may be said that, roughly, the maxima and 

 minima occurred within two hours of the maxima and minima of o, 

 but since in some instances this happened previous to the maximum 

 and minimum out of doors, the warming up of the colony due to the 

 increasing activity of the bees must have had its effect. 



To show how closely the maxima of the thermometers in the outer 

 parts of the cluster ultimately approached the readings of the central 

 thermometers, it may be said that while in April the maximum of 

 the outer thermometers in the hive was 19° C. (66.2 F.), in the fol- 

 lowing months it rarely fell below 34° C. (93.2° F.). In September, 

 however, with the general cooling of the atmosphere, it fell to 28° C. 

 (82.4° F.). This showed the tendency at the close of the experiment 

 for the colony to approach winter conditions. The facts show again 

 the unity or equalization of the temperature throughout the cluster, 

 which in the brood-rearing season ranges between 34° and 35° C. 

 (93.2° to 95° F.). The maxima and minima are shown in Table V. 

 The range of the oscillation shows the constancy of the temperature 

 during the height of the season and the greater fluctuations in spring 

 and fall. 



