4 BULLETIN 1328, U. S. DEPAETMEXT OF AGRICULTURE 
be. The bee having left the tunnel, the counterbalance now has a 
greater moment than the empty tunnel, the second door is closed, 
contact is broken, and the first door is opened, so that the mechanism 
is now read}^ to count the next bee. This seesaw motion continues 
as long as bees are passing through the tunnel. The illustration 
(fig. 1) shows an incoming gate. The only difference between this 
and an outgoing gate is the presence of glass immediately in front 
of the tunnel on the outgoing gate, and a different position of the 
binding posts. The tunnels adopted after some experimentation 
were 15 millimeters long, from 6.5 to 7 millimeters wide, with a 
curved upper portion from 4.5 to 5 millimeters at the highest point. 
These were so adjusted that a 6T-milligram weight placed at the 
base of the rear door brought the tunnel down to the lower stop. At 
other times T5-milligram and 47-milligram weights were used, but 
most of the data were obtained with the first-mentioned adjustment. 
Fig. 1. — Apparatus for recording by electrical contact the ingress of bees into 
the hive 
Since this device, in the course of this investigation, has shown 
certain undesirable features, it remains, in a search for the ideal 
counting device, to consider briefly the possibility of counting bees 
by means of the amplification of a current whose circuit is closed 
by the body of the bee itself. 
In discussing the possibility of this method with the writer, radio 
experts have suggested that it might be better to get the bee to pass 
between the plates of a small condenser and thus to vary its dielectric 
constant, and then to use this variation to record the passage of the 
bee. Assuming that expense is of no consideration, it is still ques- 
tionable whether this method would have any advantage over the 
one used in this investigation. Some device would be needed before 
and after the condenser to regulate the passage of the bees, and these 
obstructions might be as great as or greater than that offered by the 
