404 THE EMPIRE OF THE AIK. 



The class of fishes, as might be expected, presents few specimens of 

 flying creatures; perhaps a dozen species can project themselves from 

 the sea, glide a few air yards with great effort, and return to their 



liquid element. 



•* * * * * * * 



Flight progression is certainly the most elegant mode of motion given 

 by nature to her creatures. But all birds are not equally gifted although 

 each animal has modes of flight appropriate to his needs, for life depends 

 on this. 



Which of all the birds is best endowed for flight by nature? A ques- 

 tion often put, and answered many ways. 



Is it ihe eagle, with his majestic sweep f He is certainly great; the 

 king of the air; but the humble pigeon outstrips him' in the sky, as the 

 greyhound flashing by the mastifl. Is it the frigate bird, with his great 

 spread of wings? Assuredly no, I answer: there are circumstances 

 when the frigate bird can not rise from the ground. Is it the group 

 of the great vultures'? These may be the best for man to imitate, 

 but for speed, for endurance, for quick evolution, their vast wings re- 

 quire too much space to produce modes of flight entitling them to bird- 

 life primacy. A condor can not get under way and rise like a sparrow. 



May it not then be the charming swallow, so lively, so ([uick, so agile ? 

 Alas! no; her great proportion of wing surface is the sport of a gust of 

 wind. Her small mass is insufficient in great currents of air. The 

 sparrows are after all the best endowed for bird flight and bird life. 

 Speed, ([uickness in action, diflicult feats, constant readiness, all are 

 compassed by them. And yet these birds during their whole year, do 

 not flit as far as sea birds in a month. 



From these remarks it is safe to conclude, and to say to ourselves, 

 that eacli bird flies perfectly, according to his needs. Yet, from bird 

 point of view, the spjirrow approaches the type of perfection. As to 

 speed, he may outstrip the pigeon ; as to power, he can rise vertically 

 to considerable lieights; as to journeys, he equals other birds, for he 

 also has his periodical migrations. 



This selection may at flrst sight appear curious; but it will be re- 

 membered that it is only small birds which compass all the monstrous 

 difficulties of flight. The warblers, the sylvias, the humming-birds, 

 are constantly performing astonishing feats and gymnastics; they are 

 athletes and acrobats. We may even at this point fornuilate an ornitho- 

 logical law, and here it is : The proportional power is in direct ratio 

 to the smallness of the bird. 



We do not generally appreciate this power ; and yet let us observe 

 the metallic elasticity of the warbler's muscles, in its zigzag flashings 

 in ]mrsuit of a fly; observe the wings' pulsation, vibrating like tongue 

 of steel, and almost producing harmonic notes; and conceive of the 

 energy spent in such rapid motions. A condor whose pectoral muscles 

 could produce such lightning beats, needs have his wings of steel ; their 

 roar would be as thunder. 



