BONES OF THE WIXGS. 101 



can play freely, without the least pressure upon any 

 of the important vessels which it contains. 



All the bones of the wings are well formed, and the 

 fingers, though only one of them is perfect, can be 

 distinctly traced. The humerus is the longest and 

 also the strongest and heaviest bone in the wing ; 

 and the lengths of the others diminish in the pro- 

 portion of their other dimensions ; so that though 

 when the wing is moved, the different parts move 

 with velocities proportional to their distances from 

 the centre of action, yet the effect of the entire wing 

 is very uniform, and the bird, when in powerful action, 

 may be said to fly with the whole of it, that is, to 

 strike the air with nearly equal effect with the whole 

 of its under surface. The stiffness of the intermediate 

 joints in such a wing, the perfect freedom of the 

 shoulder joints, and the remarkably steady base which 

 from their size, form, and place, the scapular, the 

 coracoid, and the furcal bone, give to the centre of 

 action, render the flight of the bird exceedingly 

 smooth ; and, though it is heavy for its bulk and even 

 for the length of its wings, the jer falcon never 

 appears in the least to labour on the wing. Birds 

 more loosely boned, in any of the respects that 

 have been mentioned, are incapable of this perfect 

 steadiness and beauty of flight. The short winged 

 ones of them flutter, as if they had not wing enough, 

 and the long winged ones have their bodies tossed 

 upward by the down stroke of the wings, and down- 

 ward by the up stroke, as if their wings were too 

 much for their management. This falcon, how- 

 ever, which has to range ovr somewhat bare and 

 very stormy pastures, has its wings and its body 



