174 COVERING OL ANIMALS. 



the purpose they answer, where the feather is expo- 

 sed to the water or air, viz. to produce a smooth, 

 connected surface, — while the down in this under 

 situation, is more useful for the warmth of the bird. 



Fig. 32. 



The body feather of a bird, exhibiting the discontinuance of the 

 clasps at the lower part of the stem. 



B. What a striking and beautiful design ! If the 

 clasps had been produced by a set of causes, consti- 

 tuted by accident, and acting as all ignorant causes 

 must act, by a general operation, then we are at lib- 

 erty to ask, why the apparatus was discontinued only 

 at this part of the feather, where the occasion for it 

 ceases, or where the feather i» covered ? What natu- 

 ral tendency could there be in covering the feather 

 to prevent the formation of the little hooks ? We see 

 a regard to utility, and can give no other solution. 



T. Did you ever notice another curious circum- 

 stance in this remarkable structure ? 



A. The filaments are broad and flat, like the 

 sticks of a fan. Owing to this circumstance, they 

 easily bend for the approach of one another, whilst 

 in the other direction they bend with difficulty. 

 Now, it is observable, that it is in this latter direction, 

 the feathers strike upon the air and in which, conse- 



