POSITIONS ASSUMED BY BIRDS IN FLIGHT. 167 



the unfolding of the units of the wing seems to be 

 sequential, starting with the humerus, and not simul- 

 taneous. 



This is, I fear, directly at variance with the writings 

 of many leading ornithologists and anatomists, and 

 I can only put forward the photographs in support of 

 my observations. Undoubtedly the arrangement and 

 articulation of the wing-bones appear to indicate that 

 the unfolding will take place mechanically throughout 



FIGURE 4. — GONE. 



[Photographed by Bentley Beetliani.) 



on any one part being extended, but laboratory theories, 

 however much they may be upheld by inanimate evidence, 

 cannot pass unchallenged when they are found to be 

 in apparent contradiction to observation of the living 

 action supported by corroborative photographs. 



Figure 3 shows the bird at the very moment it is diving 

 from the cliff, only the tips of its toes touching the rock, 

 and it will be noticed, as intimated before, that the slope 

 of the body is strongly upwards. The wings have not 



