The kingfisher darts along like an arrow; fern owls, or goatsuckers, glance in the dusk over the tops of trees like a meteor; swallows sweep over the surface of the ground and water, and distinguish themselves by rapid turns and quick evolutions; swifts dash round in circles; and the bank martin moves with frequent vacillations like a butterfly.
Most small birds hop; but wagtails and larks walk, moving their legs alternately. All the duck kind waddle; divers and auks walk as if fettered, and stand erect, on their tails. Geese and cranes, and most wild fowls, move in figured flights, often changing their position.
—From "The Natural History of Selbourne," by Gilbert White.
THE ORIGIN OF RIVERS.
Let us trace a river to its source. Beginning where it empties itself into the sea, and following it backwards, we find it from time to time joined by tributaries which swell its waters. The river of course becomes smaller as these tributaries are passed. It shrinks first to a brook, then to a stream; this again divides itself into a number of smaller streamlets, ending in mere threads of water. These constitute the source of the river, and are usually found among hills.
John Tyndall.