WIND AND FLIGHT 125 



dislike this." By way of answer we may say that 

 an undoubted fact is no better than blank cartridge 

 if it does not apply to the particular case. It is true, 

 no doubt, that whereas a horse or a cow will always 

 turn tail to a strong breeze, a bird always stands 

 facing it. I have just seen some forty Starlings on 

 a dead poplar tree. All, to a bird, were facing the 

 breeze. Gulls or Oyster-catchers may often be seen 

 by the seashore all facing to the front like soldiers 

 when the word " Eyes front ! " is given. The 

 nictitating membrane protects their eyes from the 

 wind, and there is no tumbling of their neat plumage. 

 But would such a thing be likely to happen during 

 flight from whatever direction the wind was blowing ? 

 A bird must have some velocity of his own ; he 

 cannot be like a leaf carried by the wind ; he is too 

 heavy for such a method of travelling, and, were he 

 to try it, he would soon descend precipitately to 

 earth. But though he necessarily has velocity of 

 his own added to that of the gale, it might seem 

 possible that a terrific tail-wind might occasionally 

 cause difficulty. Though the bird's body outpaces 

 the gale, yet there may be moments when the gale 

 overtakes his wings. When the down-stroke is over, 

 the wings are moved backward as well as upward 

 preparatory to the next stroke, though in long- 

 distance horizontal flight the forward and backward 

 movement is not very great. The velocity of the 

 wind, too, varies from moment to moment, and 

 Professor Langley showed that the greater the 

 velocity the greater is the irregularity. Even a 

 steady wind proves to be gusty when properly tested. 

 If, then, the wings happened to be moving backward 



