378 THE WORLD OF THE SEA. 
from great heights, and gathering a vast momentum, shoot beneath 
the waves like an arrow. 
The power of flying is the distinguishing function of birds. 
The atmosphere is to them what the ocean is to fish. Flight and 
swimming are only, says Lacépeéde, the same motion carried on in 
different fluids. The bird swims in the air, and the fish flies in the 
water. 
Those sea-birds which are fitted for flying always excel in 
the art, and are capable of being a long time on wing. The 
Sea-swallows are remarkably agile, rivalling their terrestrial repre- 
THE SEA-SWALLOW. 
(Sterna hirundo.) 
sentatives in describing aerial labyrinths, and crossing each other’s 
paths with dangerous velocity. But the great master in the art of 
flying is the Frigate-bird (Lachypetes aquila); its body weighs 
only a few ounces, while its wings have a great expanse. The 
frigates keep mostly in the higher regions of the atmosphere, and 
precipitate themselves like an arrow, regaining their balance with 
ease and rapidity; one moment they may be seen resisting the 
most violent wind, at another, drifting with the lightest zephyr. 
They are bad fishers, but they compensate for their want of skill 
by bold and fearless robbery. They are the highwaymen of 
the sea. From his aerial height the frigate watches an honest, 
laborious gull seize a fish, and mount into the air, either to carry 
its prey to shore or to enjoy its. feast. In an instant the frigate is 
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