The Return to the Nest 



distances, in unfamiliar directions and into 

 regions which they have not yet visited, are 

 the Pigeon and the Cerceris guided by recol- 

 lection? Is memory their compass when, on 

 reaching a certain height, whence they can, 

 so to speak, pick up the scent after a fashion, 

 they dart with all their power of wing 

 towards the horizon where their nests are? 

 Is it memory that traces their road through 

 the air, across regions which they are seeing 

 for the first time ? Obviously not : there can 

 be no recollection of the unknown. The 

 Wasp and the bird are unacquainted with the 

 country around; nothing can have told them 

 the general direction in which they were 

 moved, for the journey was made in the 

 darkness of a closed basket or a box. Lo- 

 cality, relative position: everything is un^ 

 known to them; and yet they find their way. 

 They therefore have something better than 

 mere memory as a guide : they have a special 

 faculty, a sort of topographical sense of 

 which we cannot possibly form an idea, hav- 

 ing nothing similar ourselves. 



I will show by experiment how subtle and 

 precise this faculty is within its narrow pro- 

 vince and also how obtuse and dull it be- 

 comes when driven to depart from the usual 

 337 



