﻿76" ON THE CLASSIFICATION OF BIRDS. 



been copied and recopied in the volumes of others ; but, 

 on the other hand, they may hope to see many of those 

 subjects placed in a new light, accompanied by some 

 original information, which peculiar circumstances have 

 placed us in the way of acquiring. But to proceed : — 

 We shall only take a hasty glance at the construction of 

 feathers in general, and then proceed to notice those 

 particular modifications of their form which influence 

 their natural habits, and indicate their natural affinities. 



(70.) The feathers which are upon a bird are of three 

 different kinds : 1. Those which are next to the body, 

 and are altogether concealed from the sight ; 2. Those 

 which are external, but are used in flight; 3. Those 

 by which the body is sustained in the air. The sub- 

 stance which composes the first is known by the name 

 of down. It is more analogous to the soft fur of qua- 

 drupeds than to the feathers, properly so called, of 

 birds, inasmuch as it does not possess that distinctness of 

 parts which is observable in a perfect feather. Some 

 of its obvious uses are to keep the body in an equal de- 

 gree of temperature, and to resist cold or wet, so that it 

 performs the same office as an under- vestment of flannel 

 does to the human skin. This inner covering, however, 

 is not to be found in all birds; or, at least, it is so slight 

 in some that its presence is only indicated by soft hairs 

 thinly scattered over the body, as we see in domestic 

 fowls and other poultry. It may be observed, however, 

 that in such birds which have not, like the ducks, a dis- 

 tinct layer of down, the lower part of the external feathers 

 supplies the deficiency, so that it may be said the down 

 is only removed to another situation, and instead of being 

 detached, it is placed at the base of the true feathers, 

 where it equally covers and protects the skin. Down, 

 when existing as a separate substance, is mostly confined 

 to the bodies of aquatic birds, for the manifest intention 

 of additional warmth, and to render the skin still more 

 inaccessible to the watery element ; this delicate sort of 

 feathers, as is well known, is most developed in the 

 duck family, particularly on the eiders and swans. It is 



