THE METHOD OF HOMING PIGEONS. 



761 



animals, by the processes going on in their bodies, must have 

 some notion of time. This would give the " how long " element 

 in the problem. The " how fast " might be given by such an in- 



Fig. 2. 

 ^Flight of six pigeons, covered cage. 



strument as we find in the otoliths resting on the sensory hairs of 

 the maculcB acoustics, these hairs bending under the weight more 

 or less, according to rate of movement. The " which way" could 



