WINTERING OUTDOORS 
899 
Fig. 7.—The original four-colony winter case as used by Ira Bartlett of Michigan 30 years ago. He was 
probably the original user of the principle. 
hives, such as are described under the head 
of Hive-making, or packing-cases, should 
be used. There are two forms of these 
double-walled hives, one having bottom 
packing and the other a removable bottom- 
board which is made of single-thickness 
%-irmh lumber. 
There has been some discussion as to 
whether these winter hives should have 
bottom packing or not. From some ex¬ 
periments with electric bulbs apicultural 
experts in the Bureau of Entomology came 
to the conclusion that there is a great 
advantage in having the bottom packed, as 
