Andes — one of the largest of flying birds, having a wing- 

 span of something over nine feet : 



" When the condors are wheeling in a flock round and 

 round any spot, their flight is beautiful. Except when rising 

 from the ground, I do not recoUect ever having seen one of 

 these birds flap its wings. Near Lima, I watched several for 

 nearly half an hour, without once taking off my eyes ; they 

 moved in large curves, sweeping in circles, descending and 

 ascending without giving a single flap. As they glided close 

 over my head, I intently watched, from an oblique position, 

 the outUnes of the separate and great terminal feathers of 

 each wing ; and these separate feathers, if there had been 

 the least vibratory movement, would have appeared as if 

 blended together ; but they were seen distinctly against 

 the blue sky. The head and neck were moved frequently, 

 and, apparently, with force, and the extended wings seemed 

 to form the fulcrum on which the movements of the neck, 

 body, and the tail acted. If the bird wished to descend, the 

 wings for a moment collapsed ; and then again expanded 

 with an altered inclination, the momentum gained by the 

 rapid descent seemed to urge the bird upwards with the even 

 and steady movement of a paper kite. In the case of any 

 bird soaring, its motion must be sufficiently rapid, so that the 

 action of the incHned surface of its body on the atmosphere 

 may counter-balance its gravity. The force to keep up the 



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