l62 ON THE CLASSIFICATION OF BIRDS. 
a foot is more adapted for swimming than that of the 
penguin ; and yet it is asserted by voyagers that these 
latter birds swim with such amazing rapidity that they 
will pursue and overtake even fishes ; upon which, in- 
deed, they chiefly live. This fact would he perfectly 
incredible, did it not explain indirectly the true use of 
the abortive wings of these singular birds, which being 
used as fins, gives them this superiority of swimming 
over all other birds ; and confers upon them the pos- 
session of four members for this express purpose, when 
all other birds have only two. That law of nature per- 
vading every part of the anim.al creation, which pre- 
serves the balance of powers and of faculties, by giving 
additional power to one organ, if another is unusually 
weak, is no where more strikingly and wonderfully dis- 
played than in the penguin and the frigate pelican (Ta- 
chipetes). The one is, perhaps, the longest, and the 
other the shortest, winged bird in creation, and yet it is 
in these very members that the law in question is de- 
monstrated. The feet of both birds, upon land, can do 
no more than barely support the body ; but, to com- 
pensate for this apparent deficiency, nature has thrown 
such additional powers into their wings, that aU other 
birds must confess their own inferiority. And yet these 
powers are of a totally different kind ; nay, they are the 
very antipodes of each other. The penguins would 
seem to make their way under water with almost the 
same celerity as the swallow does in the air ; but this 
is entirely owing to the peculiar structure of their wings. 
In the air the bird is utterly helpless, and would fall to 
the ground like a lump of lead. Now the Tachipetes 
has a foot even still more useless for all other purposes 
than the penguin ; it is fully as short, yet the mem- 
brane between the toes, from scarcely reaching to the 
first joint, precludes the bird from swimming : its foot, 
in short, like that of the humming-bird, is a mere in- 
strument of rest to support the body. How then, it 
may be asked, does the bird live. It may almost be 
said to live in the air. Its immense extent of wing. 
