TEMPERATURE OF THE HONEYBEE CLUSTER IN WINTER. 9 



perature readings quite close together, while thermometer 6, which 

 was near the cluster, gave readings intermediate between the three 

 thermometers of the cluster and the four others in the hive, farther 

 from the cluster. After November 22 the records of the thermometers 

 in the cluster were more widely separated and the temperature of the 

 center of the cluster (shown on thermometer 5) tended to rise gradu- 

 ally. It varied constantly, but by December 7 and from then until 

 the end of the month, it averaged between 69° and 75° F. On Novem- 

 ber 29 and December 12 the cluster temperature rose to over 88° F. 

 From the 1st of January until March 6, which ended the regular 

 series of readings, the cluster temperature became more and more 

 irregular, and on January 20 the cluster moved (probably to accom- 

 modate itself to the stores) until thermometer 2 was nearer the center 

 and showed a higher temperature than thermometer 5. The size of 

 the cluster was gradually decreased by the death of bees, and all the 

 thermometers except 2 and 6 show a gradual decrease in temperature 

 until finally, from about February 25 to March 6, they are all low 

 and of nearly equal temperature. The two thermometers giving high 

 readings continued to show in general a higher and higher average 

 temperature and to become more irregular (except from February 15 

 to March 1), the periods of increased heat becoming more frequent. 

 There was absolutely no regularity in these intervals. After Febru- 

 ary 1 the temperature of the cluster varied between 75° and 91° F., 

 the average from February 1 being 85.4° F. 



On March 6 all colonies in the constant-temperature room except 

 two were removed. The colony described above (No. 1) and one 

 other (No. 12), not to be described at present, were left. On March 

 7 at 9 a. m. the temperature of the room stood at 42° F., and the 

 temperature of the interior of the cluster was about 84° F. The 

 brine which cooled the room was then shut off and the temperature 

 of the room rose very slowly and regularly, until on March 11 at 

 8.45 a. m. it was 64° F. For the first day the temperature of the 

 cluster was slightly variable, and at 10.45 p. m. thermometer 6, which 

 had been cooler than thermometer 2, showed a rise in temperature 

 (probably due to a shifting of the cluster), and from then on to the 

 24th they were nearly of the same temperature at all times. On 

 March 8, at 3 a. m., thermometer 2 rose to 87° F. (room temperature, 

 48.5° F.), having previously shown a cooling. The cluster tempera- 

 ture then dropped slightly, showing relatively little variation until 

 at 4.15 p. m., March 9, it stood at 77.3° F. (room temperature, 

 55.7° F.). As the room temperature continued to rise, the cluster 

 temperature increased still more rapidly, until at 8.15 a. m., March 

 11, it reached 93° F. (room temperature, 64.2° F.). A little brine 

 was now turned on, sufficient to lower the temperature gradually to 

 58° F. at 9 a. m., March 12, and it again rose to 63.3° F. at 5.45 p. m., 



