MIGRATION OF ANIMALS. 27? 



quest of food. From this specific lightness, the submersion 

 of swallows, and their continuing for months under water, 

 amount to a physical impossibility. Even water-fowls, when 

 they wish to dive, are obliged to rise and plunge with con- 

 siderable exertion, in order to overcome the resistance of the 

 water. Klein's idea of swallows employing reeds and straws 

 as means of submersion is rather ludicrous; for these light 

 substances, instead of being proper instruments for assisting 

 them to reach the bottom, would infallibly contribute to sup- 

 port them on the surface, and prevent the very object of their 

 intention. Besides, admitting the possibility of their reach- 

 ing the bottom of lakes and seas, and supposing they could 

 exist for several months without respiration, what would be 

 the consequence ? The whole would soon be devoured by 

 otters, seals, and fishes of various kinds. Nature is always 

 anxious for the preservation of species. But, if the swallow 

 tribes were destined to remain torpid, during the winter 

 months, at the bottom of lakes and seas, she would act in op- 

 position to her own intentions ; for, in a season or two, the 

 whole genus would be annihilated. 



Mr. White of Selborne has favored us with the following 

 information concerning the migration of swallows. " If ever 

 I saw," says he, " any thing like actual emigration, it was last 

 Michaelmas day, 1768. I was travelling, and out early in the 

 morning ; at first there was a vast fog ; but by the time that 

 I was got seven or eight miles from home towards the coast, 

 the sun broke out into a delicate warm day. We were then 

 on a large heath or common, and I could discern, as the mist 

 began to break away, great numbers of swallows clustering 

 on the stinted shrubs and bushes, as if they had roosted there 

 all night. As soon as the air became clear and pleasant, they 

 all were on the wing at once, and by a placid and easy flight, 

 proceeded on southward towards the sea. After this I did 

 not see any more flocks, only now and then a straggler. 

 When I used to rise in a morning last autumn, and see the 

 sivallows and martins clustering on the chimneys and thatch 

 of the neighboring cottages, I could not help being touched 

 with secret delight, mixed with some degree of mortification ; 

 with delight, to observe with how much ardor and punctual- 

 ity those poor little birds obeyed the strong impulse towards 

 migration, or hiding, imprinted on their minds by their great 

 Creator ; and with some degree of mortification, when I re- 

 flected, that after all our pains and inquiries, we are yet not 

 quite certain to what regions they do migrate ; and are still 

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