234 PRINCIPLES AND CONCLUSIONS. 



circle with a radius of six kilometers, but of only three or four kilometers. If the cir- 

 cle had had a radius of six kilometers, then the bees of the transposed hive would 

 be back into the circle of action if they got more than half that distance near the old 

 position in foraging, and would have to return to the old place. But this only happens 

 if the old position is less than six kilometers away from the new. We must,, therefore, 

 accept something near three kilometers as the boundary for this circle of action for 

 this force." 



When Bethe freed 8 marked bees at each of three distances from the hive, 

 namely, 350, 400, and 650 meters, they found their way back in 1.5 to 3.5, 

 5 to 10, and 4.75 to 10.5 minutes respectively. Buttel pointed out that at 

 the normal velocity for bees, doubled because they were carrying loads, 

 the unknown force should have led them all back in 1 minute 12 seconds, 

 1 minute 36 seconds, and 2 minutes 36 seconds, for the respective distances. 

 This discrepancy can only be explained on the assumption that the bees 

 had to orient themselves with their eyes and that they made errors in doing 

 so, and thus lost time. Since the unknown force does not bring bees back 

 to the hive but only to the place where it stands or usually stood, it must be 

 memory of location. When bees are stupefied with chloroform, ether, 

 saltpeter, etc., memory of location entirely disappears, and they no longer 

 recognize their home or the place where it stands. As soon as they become 

 normal, they again begin to orient themselves with regard to the home, 

 gathering new memory pictures of the sources of nectar and pollen as well as 

 of the new hive. This also shows their capacity for learning, a fact disputed 

 by Bethe. Buttel also emphasizes the discrepancy between Bethe 's as- 

 sumption that all the bees set free within the circle of action of the "un- 

 known force" must return to the place that "draws them like a magnet," 

 and the actual results obtained by him in the box experiment. When the 

 bees were released from the box, most of them, after a few circles in the air, 

 went in the direction of the institute, but "two mounted to a height of 

 about 3 meters, made a few circles of 4 or 5 meters in diameter, and 

 then alighted on the box. I drove them away into the air again. They 

 flew in large circles about it, and then again alighted on the box. I then 

 took the box away and put it on another stone, having driven the bees into 

 the air once more. Both bees flew so high that I could no longer see them, 

 but a few seconds later they reappeared and slowly flew about the place 

 where the box had stood." Thus some bees were influenced by the "un- 

 known force" and others were not, a fact that Bethe did not attempt to 

 explain. Buttel carried out similar experiments with the same results and 

 all of them furnished evidence of memory for locality, though he regarded 

 the conditions as abnormal in comparison with those carried on at the 

 apiary. Although Bethe gave no explanation of why the "unknown force" 

 operates at a distance of but 3 or 4 km., it is really very simple, since 

 this supposedly mysterious force operates only within the space in which 

 the bees have made flights of orientation and stored up memory pictures. 



The identity of this unknown force with memory of location is further 

 proved by the following facts: If young bees are let fly not far from the 

 apiary before they have had their flight of orientation, none of them find 

 their way back to the hive, but if old bees are released at a much greater 

 distance they all return. If a colony is brought from a place more than 



