£2 CONSTRUCTIVE BEEKEEPING 



layer under the cover, it is never more than 3-4 saturated). We 

 have then air entering the hive at a temperature of 50'F. and 1-2 

 satuation which would, when heated to hive temperature, be 

 about 1-4 saturated. This air then when heated to hive temper- 

 ature, being 1-4 saturated, is capable of taking up moisture until 

 it is 3-4 saturated. The amount of moisture taken up by this air 

 is 3-4 minus 1-4 or 1-2 of its capacity at saturation. This amount 

 of water vapor would be less than 1-1000 of a pound for one cubic 

 foot of air. 



Now follow the course of this 90 degree air in passing from 

 the hive by way of the entrance. As it approaches the entrance 

 the temperature is reduced and it would give up some of its 

 water at the entrance. Could they force all the air out of the 

 hive at a temperature of 90 and fully saturated, each time the air 

 in the hive is changed 1-600 of a pound of water would be re- 

 moved. A pound of water could be expelled from the hive in 10 

 hours if the bees could change all the air of the '' hive once a 

 minute. 



When an analysis of the evaporation inside the hive is under- 

 taken we are confronted with many conditions that increase or 

 retard it. Water vapor and warm air being lighter than air at the 

 entrance, pass naturally to the top of the hive, and remain there 

 unless some mechanical force compels them to move toward the 

 entrance. This force is noticable when the hive contains smoke. 

 Under normal conditions we do not find this fanning going on all 

 through the hive. 



So far only the evaporation which takes place when the air 

 and water are at the same temperature has been considered. 

 Water can readily be turned into steam by boiling. This steam 

 begins to rise from the surface of the water long before the water 

 comes to the boiling point. "The surface of any watery liquid, 

 whose temperature is 20 degrees warmer than any superincum- 

 bent air, rapidly gives off true steam,"* applies to the evapora- 

 tion in the hive. We know the temperature of the bee's body, 



*Wells' Natural Philosophy. 



