HAWKING 24^ 



It is evident that the soaring hawk, much more 

 lightly build than the aeroplane in proportion to 

 its wing surface, and with a marvelous instinc- 

 tive knowledge of flight, takes advantage of air 

 currents, and, when they are sufficiently strong in 

 an upward degree, he is able, by gliding in circles, 

 to mount higher and higher without a flap of his 

 wings. Lacking the upward currents he would 

 fail to rise or even to maintain the same level, 

 for, after each downward glide, his ascending 

 glide would fall short of his previous elevation. 

 One can coast on a sled down one hill and up 

 another but not to the same level. One must 

 walk the rest of the way. If the up-currents are 

 not sufficient, the hawk has to do a little hill- 

 climbing by ordinary wing strokes and he then 

 glides again and swings up as far as he can. 

 The up-currents of the higher air, we now know 

 from aviators and meteorologists, are sometimes 

 very powerful, especially on days that are calm 

 enough on the surface of the ground. That 

 hawks are past-masters in taking advantage of 

 these currents no one can doubt. 



When a strong wind blows against a cliff or 



