22 



BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. 



Table Y. — Maximum and minimum temperatures of the center of the cluster during 



summer. Thermometer C. 



Month. 



Approximate 

 range. 



April 



May 



June 



July 



August . . . 

 September 



FLUCTUATIONS IN THE HIVE TEMPERATURE AND THE CAUSES. 



It has already been said that the fluctuations in the hive tempera- 

 ture were slight and that hot days and winds had very slight effect 

 on the cluster temperature. There are some minor fluctuations due to 

 internal and external disturbances which caused decrease or increase 

 in the hive temperature. 



THE EFFECT OF "ORIENTATION" OR "PLAY FLIGHTS." 



Every beekeeper is familiar with the "play nights" of young bees 

 about noon on warm sunny days. These are generally believed to 

 be "orientation flights/' in which the young bees fly forth in circles 

 and with head toward the hive in order to learn its location. During 

 the period of resumed brood rearing in August these nights occurred 

 every few days in the experimental colony. At such times ther- 

 mometer readings were taken at short intervals. Instead of causing 

 the heat of the hive to increase these flights first caused a decrease, 

 then a slight increase. Table VI presents figures for a typical observa- 

 tion, made after the bees had been confined to the hive by inclement 

 weather for three days. 



Table VI. — Effects of " " orientation flights'" of bees on the temperature of the hive. 



Aug. 28. 



6a. m. 1 



7 a. m 



8a.m. 2 



9a. m 



10 a. m 



11 a. m.3... 

 11.30 a.m.*. 



12m 



1 p. m 



2p. m.s 



2.15 p. m... 

 2.30 p. m.fi.. 

 2.45 p. m... 



3 p. m 



4p. m 



Thermometer. 



a 



34. ! 

 34.0 

 34.0 

 34.0 

 34.0 

 33.8 

 33.8 

 34.0 

 34.0 

 33.8 

 34.0 

 34.0 

 34.0 

 34. 

 34.0 



° F. 



93.2 



93.2 



93.2 



93.2 



93.2 



92.84 



92.84 



93.2 



93.2 



92.84 



93.2 



93.2 



93.2 



93.2 



93.2 



° C. 

 34.4 

 34.4 

 34.2 



o F 



93. 92 



93.92 

 93.56 



34.0 93.2 

 34.2 93.56 



33.8 

 34.0 



92.84 



93.2 



34.0, 93.2 

 34.2 93.56 



34.0 

 34.0 

 34.0 

 34.2 

 34.2 

 34.4 



93.2 

 93.2 

 93.2 

 93.56 

 93.56 

 93.92 



C. p F. 



34.4 93.92 



34.4 93.92 



34.2 93.. "6 



34.3 93.74 

 34.3 93.74 

 33.81 92.84 

 34.0: 93.2 

 34.0 93.2 

 34.2 93.56 

 34.0 93.2 



34.0 

 34.2 

 34.2 

 34.2 

 34.4 



93.2 

 93. 56 

 93. 56 

 93.56 

 93.92 



° C. p F. 

 34.4 93.92 

 34.0, 93.2 



34.0 93.2 

 34.0 93.2 



34.0 



93.2 



33.8 



92.84 



34.0 



93.2 



34.0 



93.2 



34.0 



93.2 



33.8 



92.84 



34.0 



93.2 



34.0 



93.2 



34.0 



93.2 



34.0 



93.2 



34.2 



93.56 



° c. 



33.6 

 33.4 

 33.4 

 33.2 

 33.2 

 33.2 

 33.8 

 33.6 

 33.6 

 33.6 

 33.6 

 33.6 

 33.8 

 33.8 

 33.8 



° F. 



92.48 



92.12 



92.12 



91.76 



91.76 



91.76 



92.84 



92. 4S 



92. 48 



92.48 



92.48 



92. 48 



92.84 



92.84 



92.84 



° C. 

 34. 6i 

 34.4 

 34.6 

 34.6 

 34.8 

 34.2 

 34.4 

 34.4 

 34. 8| 

 34.4 

 34.4 

 34.6 

 34.8! 

 34.8 

 34. 8 



° F. 



94.28 



93. 92 



94.28 



94.28 



94.64 



93.56 



93. 92 



93. 92 



94.64 



93. 92 



93. 92 



94.28 



94.64 



94.64 



94.64 



C. °F. 

 15.6 60.08 

 16.4 61.52 

 16.8 62.24 

 17.4 63.32 

 18.0 64.40 

 19.4 66.92 

 20. 0| 68.0 

 19.6 67.28 

 20.2 68.36 

 20.2 

 20.4 

 20.0 

 20.4 

 20.8 

 20.2 



6S.72 

 68.0 

 68.72 

 69.44 

 68.36 



i Cloudy. 



2 Bees fly slightly. 



3 First good fly for three days. 



* Quieted flight. 



& Bees fly freely again. 



« Quiet again. 



