330 THE UNIVERSE. 



There are animals, as the swallow, for instance, to which 

 flight is so easy that they seem to make a sport of it. A 

 passive force further assists their suspension in the plains 

 of the atmosphere ; air, rarefied l^y the warmth of the body, 

 penetrates into all its cavities and even to the interior of 

 the bones. Kendered thus sjoecifically lighter, like Mont- 

 golfier balloons filled with warm gas, they float without 

 efibrt amid the clouds. Such is the daring flight of those 

 condors which launched themselves from the frozen sum- 

 mits of the Andes towards the sky, and soon disappeared 

 from the sight of M. d'Orbigny, without one's being able 

 to explain how they could breathe so rarefied an atmos- 

 phere. 



The bird, though endowed with such a slight frame, 

 nevertheless surpasses in strength the ponderous engines 

 which glide along our railroads. Its vessels and fibres, 

 notwithstanding their wonderful delicacy, work and resist 

 more energetically than our heavy wheel-work and cast- 

 iron tubes; in the one is seen the finger of God, in the 

 other only the genius of man ! Launched like an arrow 

 into space, the bird, playing the Avliile, silently clears 

 twenty leagues an hour. A locomotive going at high 

 pressure, enveloped in fire and smoke, attains the same 

 speed only by consuming heaps of coke and water amid 

 the infernal uproar of its wheels and j^istons. 



According to Sir Hans Sloane, the sea-mews which 

 nestle on the rocks of Barbadoes take every day a journey 

 over the sea of 130 leagues, to amuse themselves and seek 

 for food on a distant island. The industry of the animal 

 thus excelling that of man. 



On their adventurous excursions birds follow their 

 track unerringly, guided by sensations of an unknown 

 nature and of extreme delicacy, among which sight and 



