230 MOVEMENT 



that this bone described round the shoulder joint a 

 cone with an elliptical base, and that the posterior edge 

 of the wing was raised as the wing was depressed. 

 This was due to the resistance of the air. After the 

 phase of depression was over, the feathers, by reason 

 of their resiliency, returned to their natural position, 



Fro. 160.— Myographic curves taken from different birds in Bight. Line I, chrono- 

 graphic curve 100 vibrations to the second. Line II, tracing of a pigeon's muscle. 

 Line III, duck's muscle. Line IV, buzzard's muscle. Line V, hawk's muscle*. 

 In all the tracing the undulations a correspond lo the elevation of the wing and 

 the undulations b to the descent. 



so that during the period of the rise the under surface 

 of the wing was turned slightly forwards. 



Chronophotography applied to the Study of Flight.— 

 It might be urged that the apparatus which was fitted 

 to the bird could modify the character of its flight. 

 So no sooner had we devised the chronophotographic 

 method than we made use of it to control the results 

 obtained by purely mechanical means. The results 



