FIFTEENTH ANNUAL YEAR BOOK — PART VTII. 511 



mometer 5) tended to rise gradually. It varied constantly, but by De- 

 cember 7 and from then until the end of the month, it averaged between 

 69° and 75° F. On November 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 

 accommodate itself to the stores) until theremometer 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 the 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 abso- 

 lutely no regularity in these intervals. After February 1 the tempera- 

 ture 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 

 temperature 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 tem- 

 perature 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° at 5:45 p. m., March 15. Dur- 

 ing this period the cluster temperature followed the room temperature, 

 but remained constantly over 20° warmer. The room was again cooled 

 slowly, and the cluster temperature dropped until on March 16, at 3 p. m., 

 the room was 49° F. and the cluster 77.5° F. As the room continued to 

 cool, the cluster temperature increased, the bees responding to the colder 

 temperature, until at 4:15 a. m., March 17, the room was 48° F. and the 

 cluster 88° F. The room then gradually warmed, and again the tempera- 

 ture of the cluster dropped and then again rose with the room tempera- 

 ture, remaining always over 20° warmer. At 6:45 p. m., March 19, the 

 brine was turned on full and the room cooled rapidly, reaching the mini- 



