520 IOWA DEPARTMENT OF AGRICULTURE 



even on the covers. It therefore appears from these few observations 

 that in the two cellars at 40° F. the moisture was more in evidence in 

 the poorly ventilated cellar and that when the temperature was raised to 

 45.5° or 52.5° F. no condensation occurred. In this connection it should 

 be remembered that the cellar temperature is often higher than that of 

 the outer air, thus giving the atmosphere a greater capacity for water 

 vapor. For example, if air comes from the outside at 0.0° F. into a cellar 

 where it is warmed to 45° F. its capacity for moisture is increased thereby 

 almost eight times (barometer, 30 in.) so that even if the atmosphere at 

 0° F. is saturated, it is capable of taking up much more moisture when 

 it reaches the cellar temperature. Moist air passing from the cellar will 

 often cause frost to form about the ventilating holes. 



The only conclusions that can safely be made from the data on these 

 four cellars is that concerning the capacity of the atmosphere for water 

 at different temperatures. Other factors entered into the wintering of 

 bees in these four cellars so that probably no reliable conclusions could 

 be formed from data as to the food consumed by the various colonies, even 

 if these were available. 



In discussing the condensation of moisture in the hive and the various 

 methods by which it may be avoided, one must not lose sight of the fact 

 that little is definitely known as to the effects of such condensation or of 

 a high relative humidity on the wintering of bees. From the experience 

 of numerous beekeepers there is justification for concluding that bees win- 

 ter better in the dryer cellars, but it is not so clear whether this state- 

 ment would hold true for all cellar temperatures. In most systems of 

 cellar ventilation the object accomplished is not so much to provide oxy- 

 gen for the bees as to eliminate the exhaled moisture without too great 

 condensation. The amount of oxygen needed to oxidize a couple of pounds 

 of honey per month is not great. Even in a cellar in which a ton of honey 

 is consumed during the winter, as in the theoretical case cited, sufficient 

 oxygen would probably get in without any special provision for ventila- 

 tion. This is not true for the elimination of the water, however. 



In discussing the exclusion of moisture from the hive it is necessary 

 to bear in mind one other hiding place for moisture, usually overlooked. 

 In hives where condensation is common the hive and cover often become 

 saturated and sufficient moisture may be held in this way that it comes 

 through and blisters the paint on the outside surface of the hive. It is 

 clear that on account of this absorption of water by the hive many records 

 of weights on the removal of bees from the cellar fail to give accurately 

 the loss in weight by the consumption of honey and the death of bees. 

 Much honey finds its equivalent in the water in the soaked hive. Before 

 drawing any conclusion as to the honey consumed we must be sure that 

 condensation or evaporation do not affect the weights of parts assumed 

 to be constant. A reverse example of this phenomenon is to be found in 

 some records made of the weight of a hive and combs (without bees) made 

 recently. The hive lost weight constantly by evaporation when placed in 

 a dry room. 



