The motion of the branches of trees produced by the wind increases, doubtless, the disposition for sleep in many birds; this may be exemplified in the common fowl; for placing its bill under the wing, even in broad day-light, and swaying it to and fro in the hand for a very short time, will produce sleep. Most of the tribe of birds sleep during the night; but there are many exceptions to this. Owls in particular are, during the night, much more active than in the day; their sight, similar to that of cats, appears to serve them best in the dark. Many of the duck tribe are not only wakeful, but feed during the night; so also do the nightjars. The nightingale, and a few other song-birds, are also wakeful while in song, during at least some portion of the night.—Montagu.

Slime, s. Viscous mire, any glutinous substance.

Slimy, a. Overspread with slime; viscous, glutinous, as the skin of an eel.

Sling, s. A missile weapon made by a strap; a kind of hanging bandage.

Sling, v. To throw by a sling; to throw, to cast; to hang loosely by a string; the strap attached to a rifle, and used by the marksman to steady his aim when a rest is not to be had.

Slip, v. To let loose; to throw off anything that holds one; to unloose a greyhound.

Slip, s. The act of slipping, a false step; mistake; a twig torn from the main stock; a leash or string in which a dog is held; an escape; a long narrow piece.

Slipknot, s. A bow knot, a knot easily untied.

Sloop, s. A small ship.

Slot, s. The track of a deer.