238 MOVEMENT 



were made to correspond to the same attitudes* for 

 convenience of comparison, and to show the exact 

 position in space of the body and wings (Fig. 167). 



From these photographs we have been able to con- 

 struct a series of bas-reliefs showing the successive 

 attitudes of the bird. 



This kind of representation is almost the only way 

 of illustrating the actual movement during flight, for 

 mere ocular observation would not give the least idea. 



* '• We need not here repeat the analysis of these photographs, which 

 have afforded us complete information of the movements of birds from 

 the point of view of kinetics, and from which we have attempted to 

 measure the amount of work performed during the act of flying by 

 means of the degree of acceleration imparted to the body." — See Le 

 Vol ties Oiseaux, p. 324. 



