THE FEET. 59 



of the shallows with feet that have the toes free, as 

 is the case with the dipper, use the wings in the 

 water. But wings are not very efficient instruments 

 of progressive motion either on the ground or in the 

 water, though they are of advantage in balancing on 

 land, and in ascending or descending in the divers. 

 All wings, whether perfect or imperfect, are for med 

 and articulated on the same general plan ; and though 

 they admit of a little inclination to the front or the 

 rear, their principal motions are always across the 

 axis of the body. 



From what was formerly said of wings acting more 

 efficiently in an atmosphere rather rare than in a 

 denser one, it follows that they must act still less 

 efficiently in water than in the densest atmosphere. 

 Indeed water is so nearly of the same specific 

 gravity with the bird, that an action of the wings 

 analogous to that of flying in the air, could not 

 possibly be performed in the water. Air the free 

 air of heaven is therefore the proper element for 

 wings, and their proper function is flying ; so that 

 any other which they may perform must be regarded 

 as a departure from the typical character of a bird, 

 of which feathered wings are the grand external 

 characteristic. 



THE FEET. 



The posterior extremities, or feet, of birds, are 

 their chief organs of progressive motion, and their 

 chief supports when at rest, upon the ground or 

 other solids. But the feet perform more operations 

 than the wings. In some birds they are used for 

 clutching or killing prey ; in others for scraping in 

 the ground for food, and also in the digging of bur- 

 rows arid the preparation of other places for the depo- 



