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CHAPTER XI. 



FLIGHT OF BIRDS. 



IN the beautiful apologue given by Plato in his 

 Protagoras, in which Epimetheus is represented as 

 distributing to all animals the qualities best adapted 

 to their several modes of life, we find it said that " to 

 some he gave wings to show them that their safety is 

 in the air." 



The flying of a bird in the air is performed on 

 similar principles to that of a fish swimming in the 

 water, with this difference, that the bird is more heavy 

 in comparison with the air, than the fish in comparison 

 with the water. At first view, it might be thought 

 impossible for so huge an animal as the Ostend whale 

 (Balcenwptera boops ?), weighing four hundred and 

 eighty thousand pounds, to swim in the sea, con- 

 sidering that its body, so far as the bones and muscles 

 were concerned, must have been considerably heavier 

 than water. Yet by a singular contrivance it is at 

 once buoyed up in the sea, and rendered so much 

 lighter than water, that it floats on the surface when 

 dead. This consists in an enormous layer of an oily 

 substance called blubber, immediately under the skin. 

 We are well justified in using the epithet " enor- 

 mous," from the fact that in the Ostend whale the 

 blubber measured four thousand gallons, and weighed 

 a twelfth of the whole body. With a large propor- 

 tion, therefore, of a light body like this to buoy it 

 up, so far from finding it difficult to swim, it would 

 require a great effort in order to dive deep into tjie 

 water. 



