KITE. 65 



lungs, their bones, their cellular tissue, their feathers, — in a 

 word, almost every individual part admit it into their in- 

 terstices ; thus giving them a degree of specific levity that 

 no other class of animals is endowed with : which, however, 

 does not render them the sport of every wind that blows, for 

 by means of their vigorous wings formed to take strong hold 

 of the air, of their muscular force, the agility of their move- 

 ments, and their powers of steerage by means of the prow 

 and rudder of their little vessel, their head and tail, they can 

 counteract this levity. 1 '' Rennie enters further into this sub- 

 ject ; he says, " The lungs of birds have several openings 

 communicating with corresponding air-bags or cells, which 

 fill the whole cavity of the body from the neck' downwards, 

 and into which the air passes and repasses in the process of 

 breathing. This is not all : the very bones of birds are 

 hollowed out with the design of receiving air from the lungs, 

 from which air-pipes are conveyed to the most solid parts of 

 the body, and even into the quills and plumelets of the fea- 

 thers, which are hollow or spongy, for its reception. As all 

 these hollow parts, as well as the cells, are open only on the 

 side communicating with the lungs, the bird requires only to 

 take in a full breath to fill and distend its whole body with 

 air, which, in consequence of the considerable heat of its 

 body, is rendered much lighter than the air of the atmo- 

 sphere. By forcing this air out of -the body again, the weight 

 becomes so much increased, that birds of large size can dart 

 down from great heights in the air with astonishing ve- 

 locity." * 



Kites choose for their breeding-place forests, or copse- 

 wood, without showing any decided preference for mountain- 

 ous localities ; and are often seen in spring, rising in their 

 beautiful and circling flight above these chosen spots, uttering 

 their clear note of joy. The situation selected for the nest 



* Insect Transformations. 



