NATURAL THEOLOGY. 171 



This is one of the properties which renders him an 

 animal of all climates and of all seasons. He can 

 adapt the warmth or lightness of his covering to the 

 -temperature of his habitation. Had he been born 

 with a fleece upon his back ? although he might haye 

 been comforted by its warmth in high latitudes, it 

 would have oppressed him by its weight and heat, as 

 the species 'spread toward the equator. What art 

 however does for men, nature has in many instances 

 done for those animals which are incapable of art. 

 The clothing of its own accord changes w r ith their 

 necessities. This is particularly the case with that large 

 tribe of quadrupeds which are covered with furs. 

 Every dealer in hare skins and rabbit skins, knows 

 how much the fur is thickened by the approach of 

 winter. It seems to be a part of the same constitu- 

 tion and the same design, that wool, in hot countries, 

 degenerates, as it is called, but in truth (most happi- 

 ly for the animal's ease) passes into hair ; whilst, on 

 the contrary, that hair in the dogs of the polar re- 

 gions, is turned into wool, or something very like it. 

 To which may be referred what naturalists have re- 

 marked, that bears, wolves, foxes, hares, &c. which 

 do not take the water, have the fur much thicker on 

 the back, than underneath ; whereas, in the beaver, 

 it is the thickest beneath, as are also the feathers in 

 the water fowl. We know the final cause, the use 

 and benefit, of all this ; and we know no more. 



T. What is there remarkable in the covering of 

 birds ? 



