48 



BULLETIN" 1339, U. S. DEPARTMENT OF AGRICULTURE 



Table 10. — Actual and predicted gains and percentage of actual gain to predicted 

 gain in colony weight for the spring period 



Date 



Actual 

 gain 



Predicted 

 gain 



-|pX100 



Date 



Actual 

 gain 



Predicted 

 gain 



-^-xioo 



1922 

 May 10. 



980 



5,900 

 2,550 

 2,410 

 ■ 2, 220 

 1,110 

 1,670 

 3,700 

 3,690 

 4,610 

 4,080 

 3,320 



1,740 

 4,453 

 2,187 



177. 55 



75.47 

 S5.76 



1923 

 May 18 



3,065 

 2,750 

 2,850 

 2,940 

 2,295 

 1,000 

 3,100 

 3,470 

 3,925 

 4, 230 

 3,680 

 4,250 

 1,765 



2,709 

 3,138 

 2,724 

 2,573 

 2,197 

 1,341 

 2,609 

 3,322 

 4,151 

 4,470 

 3,148 

 4,579 

 1,962 



88. 38 



11. 



19... 



114.10 



12 



20... 



95. 57 



13 



3, 268 135. 60 

 2,224 1 101.09 

 2, 310 208. 10 

 3,308 I 198.08 

 3,177 ! 85.86 

 3,479 94.28 

 3,544 ! 76.87 

 3,403 83.40 

 3,948 ! 118.91 



21 



87.51 



14 



22 . 



95. 72' 



15. 



23 



134. 10 



16. 



24... 



84.16 



20 



25 .. 



95.73 



21 



26 



105. 75 



22 _. 



27 



28 



105.67 



23 



85.54 



24 



29 



30 



Total 



107. 74 





111.16 









75, 560 



75, 964 



100. 53 



To take specific days as examples, on May 14, 1922, the actual 

 gain was 2,220 grams and the predicted gain for that day was 2,224 

 grams. By arbitrarily making relative humidity and the variation 

 of relative humidity equal to the average of these factors, increasing 

 the hours of sunshine from 6.9 to 14.2, and allowing the other 

 weather factors to remain as they were, the predicted gam would be 

 2,928. Thus the changing of these three weather factors theoreti- 

 cally resulted in a gain of 704 grams. 



On May 23, 1923, the net gain is low in comparison with the other 

 days, being 1,000 grams. From the standpoint of the maximum 

 changes of colony weight, the following ideal weather factors were 

 substituted for those actually found on this date: 



Hours of sunshine 14.6 hours, instead of 3.7. 



Average diurnal temperature 86° F., instead of 64.7° F. 



Average relative humidity 38 per cent, instead of 50.7 per cent. 



The remaining weather factors were not changed. Under such 

 conditions, the predicted gain is 5,025 grams. The actual predicted 

 gain with existing weather factors on May 23 is 1,341 grams. By 

 changing the weather factors, a predicted net gain of 3,684 grams 

 results. The weather factors here substituted actually occurred 

 within a few days of the 23d of May and so are not at all unreason- 

 able. The combination of optimum conditions occuring all on the 

 same day is, of course, entirely problematical; these examples are 

 given, however, merely to show the importance of the various weather 

 factors on changes of colony weight. 



CONCLUSIONS 



Although the weather is beyond the control of the beekeeper, a 

 knowledge of the influence of weather factors upon honey crops in 

 various parts of the country will be of great value in developing the 

 best beekeeping regions of the United States. 



To gain this knowledge it is first of all necessary to keep certain 

 colonies under observation, recording at frequent and regular inter- 

 vals the weight of each, and recording such accompanying phenomena 

 of the weather as may reasonably be supposed to influence either 

 the secretion of nectar or the activities of the bees. 



