BIRDS. 



309 



so that a bird, with its flying feathers on the stretch, 

 would fall much more slowly than one would suppose from 

 the difference between its specific gravity and that of the 

 air. * 



" The resistance which all the feathers on the body of 

 the bird offer to motion backwards is still greater; and it 

 increases with the force which tends to move the animal 

 in that direction. The instant that it begins to be driven 

 backwards, so that a current against its body is produced, 

 the points of the feathers rise, and take the wind with so 

 many fibres, that the resistance is very similar to that 

 made by a scaly fish, when one attempts to draw one of 

 these by the tail; and every one who has angled, and acci- 

 dentally caught even a common trout ;n that way, knows 

 that an ounce weight is as difficult to land when so hooked 

 as a pound* weight is when hooked by the head. But the 

 feathers of birds rise much more in proportion than the 

 free edges of the scales upon any fish ; and they are every 

 way as well formed for holding on in the air, as those are 

 for holding on in the water. Thus the bird may be said 

 to resist motion backwards in the air, by throwing out the 

 point of each feather like the fluke of an anchor."* 



The jaws of a Bird are not furnished with teeth, as are 

 those of a Fish, an Amphibian, a Reptile, or a Mammal, 

 for the purpose of seizing, dividing, or chewing the food. 

 The place of these organs is effectually supplied by a casing 

 of horn, terminating in a point at the tip, and brought to 

 an edge on each side of each jaw. This modification is 

 familiarly known to us as the beak or bill of the Bird. In 

 the Birds of prey, the beak is a keen carving-knife; the 



♦Mudie's "Nat. Hist, of Birds,' 5 37. 



