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SCIENTIFIC ILLUSTRATIONS 



[Wor 



only an onward change among the rock-materials of the earth, 

 but also, as plants and animals are influenced in their forms and 

 distributions by external causes, new phases and arrange- 

 ments of vitality the creation of new species, and the drop- 

 ping out of others from the great scheme of animated nature. 

 "Through the shadow of the globe we sweep into this younger 

 day." AD. 



An Enigma Concerning Worldly Wisdom. 



Birds possess worldly wisdom. Not only does the swallow 

 in Europe know that the insect which fails him there awaits 

 him elsewhere, and goes in quest of it, travelling upon the 

 meridian ; but in the same latitude, and under the same climates, 

 the lorist of the United States understands that the cherry is 

 ripe in France, and departs without hesitation to gather his 

 harvest of fruit. In the midst of the ocean, the weary bird, 

 which reposes for a night on the vessel's mast, beguiled afar 

 from his route by this moving asylum, recovers it, nevertheless, 

 without difficulty. So complete is his sympathy with the globe, 

 so exactly does he know the true realm of light, that on the 

 following morning he commits himself to the breeze without 

 hesitation. He chooses without other path than the vessel's 

 track the exact course which will lead him whither he wishes 

 to go. There, not as upon land, exists no landmark, no guide ; 

 the currents of the atmosphere alone, in sympathy with those 

 of water perhaps, also, some invisible magnetic currents pilot 

 this hardy voyager. But it is not only in respect of their 

 shrewd journeyings that birds indicate their possession of 

 worldly wisdom ; they also manifest it in all matters relating 

 to their residences. A close observation reveals the fact that the 

 nests of birds differ according to climate and the weather. At 

 New York the baltimore makes a closely fitted nest to shelter him 

 from the cold. At New Orleans his nest is left with a free 

 passage for the air to diminish the heat. The Canadian part- 

 ridges, which in winter cover themselves with a kind of small 

 pent-roof at Compie'gne, under a milder sky, do away with this 

 protection, because they judge it to be useless. The same dis- 

 cernment prevails in relation to the seasons. The American 



