WEATHEE AND CHANGE IN WEIGHT OP BEE COLONY 49 



A confirmation of the practical value of carefully kept records of 

 this sort is shown by their use in computing predicted changes of 

 colony weight. 



A mathematical analysis is necessary to show the true relationship 

 between these changes and the attendant weather factors, and with- 

 out such mathematical analysis the relative importance of various 

 weather factors upon the changes can not be shown. 



Correlations have been made between the changes in the weight 

 of two colonies of bees during the various periods of the day and 

 several weather factors. - From the standpoint of the results of these 

 comparisons the most important weather factors of those included 

 in this investigation affecting net gain during the spring period, 

 and, in order, the values of their coefficients of correlation, are, average 

 temperature, .7529; hours of sunshine, .6124; temperature varia- 

 tion, .5967; solar radiation, .5525; variation of relative humidity, 

 .4229; and average relative humidity, —.3806. 



Weather factors have but little influence upon nocturnal loss dur- 

 ing the spring period, the coefficients of correlation being, tempera- 

 ture variation, —.3439; average temperature, .1754; average relative 

 humidity, —.1264; and variation of relative humidity, —.0654. 



During the fall period diurnal changes in colony weight were dif- 

 ferently influenced by weather factors, the coefficients of correlation 

 between these changes and the several weather factors being, for tem- 

 perature variation .5570, variation of relative humidity .3800, aver- 

 age temperature —.2310, average relative humidity —.0960, hours 

 of sunshine .0595, and solar radiation —.0341. 



During the fall period the influence of the weather factors upon 

 nocturnal loss was greater than in the spring, the coefficients of cor- 

 relation being, for variation of relative humidity .5391, variation of 

 temperature .5136, average relative humidity —.4821, and average 

 temperature —.3391. 



The importance of the unknown factors influencing net gain during 

 the spring period was less than that of the unknown factors influ- 

 encing diurnal changes in the colony weight during the fall, the value 

 of the former being .3470, while that of the latter was .5360. 



For the spring period the valuejaf the unknown factors upon noc- 

 turnal loss was .7026, while that for the fall period was .5614. 



Factors influencing the secretion of nectar probably do not similarly 

 influence changes in colony weight. 



The changes in the weight of two colonies of bees placed side by 

 side continuously resembled each other. 



