340 



THE BEEi-KEEPERS' REVIEW 



is loose or if the hive is covered 

 with some absorbent or porous 

 material, the heat of the cluster 

 may cause the formation of slight 

 upward air currents which will carry 

 the moisture out the top in the 

 form of vapor. Out-of-doors there 

 may be condensation of moisture 

 in the porous packing more rapidly 

 than it can be carried off by evap- 

 oration, in which case the packing 

 becomes wet and usually thereby 

 less effective as a non-conductor. 

 With sealed covers the moisture 

 must pass out the entrance and this 

 may also occur in the form of vapor 

 if the outer air is of sufficiently 

 low relative humidity to take up 

 all the water as it comes outside". 

 The relative merits of absorbent 

 and sealed covers cannot be de- 

 termined from such statements and 

 doubtless the necessity for absorb- 

 ent covers is not always equally 

 urgent. The present occasion does 

 not seem propitious for discussing 

 this vexing question. 



Effect on the Humidity of Chang- 

 ing the Outside Teniperjvture 



Any change in the temperature of 

 the bee cellar may effect the hu- 

 midity in two ways. As the opti- 

 mum cellar temperature is ap- 

 proached, the heat produced by the 

 cluster will diminish and this de- 

 creases the food consumed and con- 

 sequently the water produced. The 

 widely varying reports of the food 

 consumed by bees in cellars find 

 their explanation chiefly in the dif- 

 ference in temperature. As the cel- 

 lar is cooled below the optimum 

 not only is there more water pro- 

 duced but the cooler atmosphere is 

 incapable of holding so much and 

 we therefore have an augmented 

 cause for condensation. 



In this connection it may be of 

 interest to record a few observa- 

 tions made on bee cellars not long 

 since. The first cellar was away 

 from any house and was without 

 any artificial heat. The temperature 

 of the air at the floor was 40° P. 

 and in the center of the cellar, 41° 

 F. There was little circulation of 

 air and moisture had condensed 

 freely in the chamber above the 

 cellar proper, under the roof. In 

 this cellar were 98 colonies in 24 

 tiers. Of these, condensed moisture 

 was seen on the bottom board of 

 21 in the bottom tier, 11 in the 

 next tier, 3 in the third and 6 in 



the top tier. There was no condensed 

 moisture on the floor. The only 

 adequate explanation for the great- 

 er number of wet colonies in the 

 lower tiers is the slightly lower 

 temperature at the floor.* If now 

 there had been more ventilation 

 provided without greatly lowering 

 the cellar temperature, this mois- 

 ture might at least have reached 

 the chamber above the cellar before 

 condensing and doubtless if the 

 temperature could have been raised 

 a couple of degrees all of the con- 

 densed moisture would have disap- 

 peared from the bottom boards. 

 There might still have been con- 

 densation on the covers, where it 

 first appears, but this too would 

 probably have evaporated at 45° P. 

 with good ventilation. 



In a second cellar where the 

 temperature was 45.5° P. at the 

 floor and 50° F. six and one-half 

 feet from the floor there was no 

 condensed moisture in any of the 

 93 colonies. Here the ventilation 

 was much more abundant and the 

 cellar was artificially heated. In a 

 third cellar, temperature 4 0° P. five 

 feet from the floor, there was 

 moisture on several covers but 

 none on the bottom boards. The 

 ventilation was excellent. In the 

 fourth cellar, temperature 52.5° P. 

 no condensation was observed even 

 on the covers. It therefore appears 

 from these few observations that 

 in the two cellars at 40° P. the 

 moisture was more in evidence in 

 the poorly ventilated cellar and 

 that when the temnerature was 

 raised to 45.5 or 52.5° P. no con- 

 densation occurred. In th^s connec- 

 tion it should be remembered that 

 the cellar tempprature is usually 

 bighpT- than that of the outer air, 

 thus giving the atmosphere a great- 

 er capacity for water vapor. Pbr 

 example, if air comes from the out- 

 side at 0.0° P. into a cellar where 

 it is warmed to 45° P. its capacity 

 for moisture is increased thereby 

 almost ei«>ht times (barometer 30 

 in.) so that even if the atmosphere 

 at 0° P. is saturated it is capable of 

 taking up much more moisture 

 when it reaches the cellar tempera- 

 ture. 



The only conclusion that can 



* This is also discussed by Holterman 

 H. P.. 1907, Placing- Hives of bees in 

 the cellar. Gleanings in Bee Culture 

 XXXV, p. 21. 



