BIRDS. a 



way, r.nsweriiig at once the purposes of warmtli, speed, iuul se- 

 curity. They mostly tend backward, and are hiid over one ano- 

 ther in an exact and regular order, armed with warm and soft down 

 next the body, and more strongly fortified, and curiously closed 

 externally, to fence off the injuries of the weather. But, lest 

 the feathers should spoil by their violent attrition against the air, 

 or imbibe the moisture of the atmosphere, the animal is furnish- 

 ed with a gland behind, containing a proper quantity of oil, which 

 can be pressed out by the bird's bill, and laid smoothly over 

 every feather that wants to be dressed for the occasion. This 

 gland is situated on the rump, and furnished with an opening or 

 excretory duct; about which grows a small tuft of feathers 

 somewhat like a painter's pencil. When therefore, the feathers 

 are shattered or rumpled, the bird, turning its head backwards, 

 with the bill catches hold of the gland, and, pressing it, forces 

 out the oily substance, with which it anoints the disjoined parts 

 of the feathers ; and drawing them out with great assiduity, re- 

 composes and places them in due order ; by which they unite 

 more closely together. Such poultry, however, as live for the 

 most part under cover, are not furnished with so large a stock of 

 this fluid, as those birds that reside in the open air. The fea- 

 thers of a hen, for instance, are pervious to every shower ; on 

 the contrary, swans, geese, ducks, and all such as Nature has 

 directed to live upon the water, have their feathers dressed with 

 oil from the very first day of their leaving the shell. Thus their 

 stock of liuid is equal to the necessity of its consumption. 

 Their very flesh contracts a flavour from it, which renders it in 

 some so very rancid, as to make it utterly unfit for food ; how- 

 ever, though it injures the flesh, it improves the feathers for all 

 the domestic purposes to which they are usually converted. 



Nor are the feathers with which birds are covered less an ob- 

 ject of admiration. The shaft of every feather is made propor- 

 tionably strong ; but hollow below for strength and lightness, 

 and above filled with a pith to feed the growth of the vane ot 

 beard that springs from the shaft of the feather on either side. 

 All the feathers are placed generally according to their length 

 and strength, so that the largest and strongest feathers in flight 

 have the greatest share of duty. The vane or beard of the 

 feather is formed with equal contrivance and care. It consists 

 not of one continued membrane ; because, if this were broken. 



