XXI EXPERIMENTS 305 



them daily taking material from the road, and 

 making a harvest on the meadow flowers, especially 

 on Salvia. According to all appearance they do 

 not fly beyond a circle of a hundred metres. How 

 then did my exiles return ? What guided them ? 

 Not memory, certainly, but some special faculty, 

 which we can only recognise by its astonishing effects 

 without pretending to explain it, so far outside our 

 own psychology is it. 



