WIND AND FLIGHT 137 



majestic performance, but this time at a higher 

 level. It is not often, I believe, that there is a 

 steady upward-trending wind extending over so 

 long a reach. In the Alps I recently saw an Eagle 

 perform a similar feat, but not on so grand a scale. 



It is clearly possible for a bird to advance in this 

 way facing with the wind instead of against it. The 

 wind acts at right angles to the bird's expanse of 

 wing and body, and, except for friction, it will not 

 matter whether it blows from in front or behind. 

 If it has a sufficient upward incline, it will not get 

 between the feathers and ruffle them. But, as a 

 fact, one very seldom sees a bird advancing in this 

 way. Still I have occasionally met with examples, 

 though I doubt whether the wind comes quite 

 directly from behind ; the bird turns himself just a 

 little sideways. Circumstances are favourable when 

 the wind blowing at a very slight angle against a cliff 

 is deflected upward. The Gull then advances with 

 the wind, head leading, wings motionless. But as 

 I have said, there is, probably, always a very slight 

 sideways turn made, so that the body from back to 

 tail is not quite in line with the course of the wind. 

 Is this to avoid a disarrangement of feathers — that 

 bothersome question ? Whatever the explanation 

 of this very slight deflection, and though this method 

 of utilising an up-current is not so common as others, 

 yet it is important that it should obtain recognition. 

 It will help us to understand soaring when we come 

 to investigate that difficult subject. 



The wonderful flight of the Albatross, his wings 

 with their spread of twelve feet or more held motion- 

 less, I cannot undertake to describe, as I have never 



