38 ANIMAL INTELLIGENCE. 



was passing along it, he turned it round, so that end b was 

 at c, and c at 6. ' In most cases the ant immediately 

 turned round also ; but even if she went on to b or c, as 

 the case might be, as soon as she came to the end of the 

 bridge she turned round.' Next, between the nest and 

 the food he placed a hat-box twelve inches in diameter 

 and seven inches high, cutting two small holes, so that 

 the ants in passing from the nest to the food had to pass 

 in at one hole and out at the other. The box was fixed 

 upon a central pivot, so as to admit of being rotated easily 

 without much friction or disturbance. When the ants had 

 well learnt their way, the box was turned half round as 

 soon as an ant had entered it, 'but in every case the 

 ant turned too, thus retaining her direction.' Lastly, 

 Sir John took a disk of white paper, which he placed 

 in the stead of the hat-box between the nest and the 

 food. When an ant was on the disk making towards 

 the food, he gently drew the disk to the other side of the, 

 food, so that the ant was conveyed by the moving surface 

 in the same direction as that in which she was going, but 

 beyond the point to which she intended to go. Under 

 these circumstances ' the ant did not turn round, but went 

 on ' to the further edge of the disk, when she seemed ' a 

 good deal surprised at finding where she was.' 



These experiments seem to show that the mysterious 

 * sense of direction,' and consequent faculty of ' homing,' 

 are in ants, at all events, due to a process of registering, 

 and, where desirable, immediately counteracting any change 

 of direction, even when such change is gently made by a 

 wholly closed chamber in which the animal is moving, and 

 not by any muscular movements of the animal itself. And 

 the fact that drawing the moving surface along in the 

 same direction of advance as that which the insect is 

 pursuing does not affect the movements of the latter, 

 seems conclusively to show that the power of registration 

 has reference only to lateral movements of the travelling 

 surface ; it has no reference to variations in the velocity 

 of advance along the line in which the animal is pro- 

 gressing.^ 



* While this MS. is passing through the press Sir John Lubbock has 



