WINGS. 103 



fins to help oar their way through the water where they 

 seem in their natural element. But rising in the scale by 

 gentle gradations through the ostrich, whose great wings, 

 though unable to lift the heavy body, are yet the sails which 

 help it skim with such swiftness over the sand oceans of 

 the desert, and the unwieldy domestic fowl, we come to the 

 grouse and its kindred, which with their power of flight, 

 heavy and labored though it be, brings us toward the typi- 

 cal bird of the air. 



What a marvel of construction is a perfect wing. Like 

 a human arm and hand, even to suggested fingers, linked 

 with powerful muscles to the bod3% with the barbs of the 

 overlapping feathers hooking together when the wing is 

 spread with hooks of microscopic fineness, making an al- 

 most air proof surface. 



Of various shapes, but always perfectly adapted to the 

 special use required of it. vShort and wide in birds which 

 spend much of their life on the ground as game birds etc., 

 growing longer and more slender in the birds of the branch- 

 es, until a swallow's wing cuts the air like a scimitar. But 

 after all, the chief source of a bird's power of flight, with- 

 out which even the wonderful wing would be useless, lies 

 in the air sacs under the skin and in the hollow bones by 

 means of w^hich a bird may render itself light or heavy at 

 pleasure by admitting or expelling the air. And here it is 

 that our bungling human attempts at flying have failed. 

 From fabled Icarus down, we have tried only to construct 

 the wing, forgetting the hidden, but more important, air 

 reservoirs, though Santos Dumont is coming nearer the true 

 principle, with his gas balloon, clumsy indeed in com- 

 parison with the birds perfect equipment. And still anoth- 

 er insuperable difiiculty that besets the human imitator. 

 A tiny bird is gifted with the powder of inhaling such great 

 draughts of air as would suffocate a man, and of breathing 

 the rarified air at great heights, and this, too, while flying, 



