412 THE BEEKEEPERS' REVIEW 



ed in thickness but becomes more compact. The entire cluster becomes smaller 

 as the outer tempei'ature falls. 



If bees can be kept in an environment such that the temperature of the air 

 immediately surrounding them is 57 degrees F. or slightly above, they are 

 saved much unnecessary and unprofitable labor. To the theoretical objection 

 that bees need exercise, it is necessary only to state that the authors have so 

 wintered bees in a cellar as vv^ell as outdoors with wonderfully successful re- 

 sults. If bees are kept in a cellar under the best conditions the results are ex- 

 cellent, but it is not proposed to discuss this more complicated phase of the 

 subject here. If wintered outside in a packing case with abundant insulation, 

 any heat generated escapes slowly and the temperature of the air in the hive 

 rarely falls below 55 degrees F. If inadequately protected, the temperature 

 of the hive can not be kept so high and the bees must generate much more 

 heat. In single-walled hives it is common for the temperature of the air 

 around the cluster to fall to freezing or lower, in which event the bees gener- 

 ate an excessive amount of heat and perhaps die when they are no longer cap- 

 able of the necessary muscular activity. The necessity of packing is thus made 

 clear, and in any locality in which the outer temperature often falls to 40 de- 

 grees F. or below it is desirable to protect bees to conserve their vitality. If 

 the temperature should fall to 40 degrees F. only a few times during the win- 

 ter, this would not be serious enough to make insulation necessary. It is ob- 

 vious, however, that winter protection is beneficial throughout practically the 

 entire United States. 



Necessity of having young bees — Bees may be compared with minute dry 

 batteries, in so far as their vital energy is concerned. They emerge as adult 

 bees with a certain amount of vital energy, and when this is exhausted they 

 die, not having power to recover lost vitality as human beings have. To with- 

 stand the hardships of winter under usual conditions, a colony must have many 

 young bees, capable of prolonged muscular work. Obviously the better the 

 wintering conditions, the less necessary it becomes to provide young bees, but 

 even with the most perfect wintering it is desirable that there be plenty of 

 young bees in the fall, so that they will be available for extensive brood-rear-' 

 ing in the spring. This calls for prolonged brood-rearing in late summer. 

 Old bees, which have been worn out earlier and are ready to die, soon succumb 

 from the work of heat-generation. 



Danger of weak colonies — In a strong colony many bees in the center of 

 the cluster may be engaged in heat-generation, and there will still remain 

 many bees to serve as insulators. A weak colony, on the other hand, has less 

 reserves for insulation, and, since heat is rapidly lost, the bees on the inside 

 must generate excessive heat in order that the outermost bees may always be 

 at a temperature of over 50 degrees F. Since the surface of a spherical 

 cluster is proportionate to the square of the diameter, while the volume is pro- 

 portionate to the cube of the diameter, it follows that a large colony cluster 

 has a relatively smaller surface for radiation of heat than does a small one. 

 Below about 50 degrees F. individual bees become numb, and so long as the 

 cluster remains active the authors have never found normal bees at a tempera- 

 ture lower than the critical temperature, 57 degrees F. In a small colony the 

 inner temperature is often many degrees warmer than that of a neighboring 

 strong colony, which doubtless explains the prolonged brood-rearing of weak 

 colonies in the fall. Most colonies which die of excessive heat-generation are 

 rushed to their doom by the temperature being high enough to start brood- 



