838 
TEMPERATURE 
observation room below. Bees were placed 
on the roof early in November. Prom then 
until along in March the inside and outside 
temperatures were taken. It was learned 
that the temperature within the cluster is 
far from being uniform, as is generally 
supposed by beekeepers. “At the temper¬ 
ature at which other insects become less 
active (begin hibernation) the honeybee 
becomes more active, and generates heat— 
in some cases until the temperature within 
the cluster is as high as that of the brood- 
nest in summer.” During the fore part of 
the readings in November and December 
the internal temperature of the cluster of 
this outside colony had a tendency to drop, 
as the outside temperature went down, un¬ 
til it reached 57 P. At that point a re¬ 
action took place; that is, the generation 
of heat began, and from this point it began 
to rise in spite of the fact that the outside 
temperature continued to drop. The clus¬ 
ter heat continued to rise until the center of 
it registered nearly 90 degrees. After the 
coldest outside temperature was reached, 
the outer air began to get warmer, and si¬ 
multaneously the temperature of the clus¬ 
ter began to sag. 
Dr. Gates tried these experiments at an 
earlier period, as reported in Bulletin No. 
96, and discovered a similar inverse ratio; 
but he did not find the exact point at which 
the colony temperature ceased to drop with 
that of the outside. Dr. Phillips and Mr. 
Demuth learned that this point is 57 F. 
When the colony is without brood, and the 
bees are not flying, the bees generate 
practically no heat until the coolest point 
among the bees reaches a temperature of 
57 F. “At this point the bees begin to 
form a compact cluster; and if the 
temperature of the air surrounding them 
continues to drop, they begin to generate 
heat.” Between 57 and 69 F. the bees do 
not do much in the way of heat generation. 
Apparently, it is desirable to have the 
surrounding temperature at such a point 
that the internal temperature of the cluster 
shall not go below 57 nor above 69; but, 
as will be shown, the questions of food and 
syrup are additional factors to be consid¬ 
ered. 
Attention will now be directed to the 
colonies, or one of them at least, in the 
constant-temperature room, where the 
mercury was kept at about 42 or 43 degrees 
F. “This temperature was chosen as being 
nearly the one generally considered best by 
beekeepers.” There were two colonies—one 
fed on honey stores and another on an 
inferior grade of honeydew honey, that 
are particularly mentioned in the bulletin. 
Colony No. 1, fed on honey stores, was in a 
constant-temperature room for 163 days, 
during which readings were taken hourly. 
At first the internal temperature of the 
cluster according to the chart hovered 
around 64 and 68. The colony fed on honey- 
dew stores showed a higher temperature at 
the beginning; when up to about 76 F. it 
began to take a sharp rise, going up to 91 
above, and on Nov. 23 the temperature 
began to show a sharp drop, the line 
running down as low as 48 on Dec. 10, 
when the colony died. Clearly the poor 
food caused uneasiness by reason of the 
accumulation of fecal matter that the bees 
could not digest, and the uneasiness caused 
activity; and activity called for a greater 
consumption of stores. The one condition 
operated against the other, finally ending 
in the destruction of the colony. The other 
colony fed on good honej'' pursued its nor¬ 
mal course thru the season. 
It is interesting to observe that the nor¬ 
mal temperature of the cluster of the col¬ 
ony fed on good stores only gradually 
increased, and this increase was doubtless 
due to the slight accumulation of feces. 
This accumulation was markedly less than 
that in the case of the colony with honeydew 
stores, not because the bees became uneasy, 
but because in proportion as the feces in¬ 
creased, the activity and temperature of 
the colony increased. This increase was not 
enough to cause the death of the colony, 
but did cause a slight reduction in the force 
in the spring. These observations explain 
the importance of good food—a food that 
will not clog the intestines. It also ex¬ 
plains a common cause of dysentery. 
Phillips and Demuth also discovered that 
the length of the life of bees either during 
summer or winter depends on the activity 
of the bees. The greater the activity, the 
shorter the term of life. 
They also found that when brood-rearing 
commences or is in progress, the tempera¬ 
ture of the cluster will rise to about that 
