4 INTRODUCTION. 



for these changes, the bountiful hand that form- 

 ed them has prepared a species of clothing unlike 

 that of all other creatures. First, a covering of 

 soft down is scattered over the skin; then, to 

 prevent so light a substance from being blown 

 about, a complete covering is provided of small 

 feathers laid closely one over another, forming a 

 sort of close under garment. Then comes ano- 

 ther covering of larger feathers, laid on so nicely, 

 that every part is covered, each feather being 

 fitted exactly to the curve of the body where it 

 is placed: this is its upper garment. Besides 

 this, there are the long wing and tail-feathers, 

 which assist it in its flight. Thus clad in a 

 garb of the warmest, and, at the same time, of 

 the lightest materials, it is singularly fitted to 

 take its course through an element in which it 

 must often encounter the extremes of cold, such 

 as would injure, and perhaps destroy, either man 

 or beast. The distances these winged tra- 

 vellers can go in a few hours is truly wonderful. 

 The great naturalist, Buffon, has observed, that 

 though the stag, the rein-deer, and the elk, can 

 go forty leagues in a single day, and the camel 

 three hundred leagues in eight days, the birds 

 much exceed them all in swiftness. If we were to 

 fix our eyes on a large bird, such as a kite or eagle, 

 when about to take its flight, in less than three 



