The Audubon Societies 



49 



reptilian cales, the e tructures called feathers, which are as delicate as they 

 are beautiful, but which, withal, are the strongest structures for their weight 

 known. We cannot take space here for a discussion of their wonderful variety 

 of form and color; we can merely call attention to their lightness, their strength, 

 their durability, the beautifully accurate way in which they grow on the bird's 

 wings and body, so that each one has a particular place and a particular manner 

 in which to lay; overlapping certain other feathers and in turn being over- 

 lapped, producing the intricate color patterns of some birds and yet at all times, 

 giving the greatest protection to the bird and involving no unnecessary weight. 



A TURKEY VULTURE SUNNING ITSELF, ILLUSTRATING THE BROAD, 

 ROUNDED WING BEST ADAPTED FOR SOARING 



We cannot take space to discuss the arrangement of the flight quills which give 

 the greatest possible resistance to the air on the downward stroke of the wing 

 and the least resistance on the upward or non-effective stroke. We can merely 

 suggest running one's fingers or a pencil through the flight quills of a fowl to 

 show how easily it passes one way and with what resistance the other. 



But there are other ways in which a bird is made light. Let some child 

 bring to school the cleaned bones from a fowl that has served its purpose at 

 Sunday dinner, not one of the bones, but all of them, for there are many lessons 

 to be learned from them. One of the things that impresses us first is their 

 unusual lightness. If we break one of them we see the reason: the marrow that 



