CWM, or Comb. A British word signifying an inlet, valley, or low place, where the hilly sides round together in a concave form; the sides of a glyn being, on the contrary, convex.
CYCLE. A term generally applied to an interval of time in which the same phenomena recur.
CYCLE OF ECLIPSES. A period of about 6586 days, which is the time of a revolution of the moon's node; after the lapse of this period the eclipses recur in the same order as before, with few exceptions. This cycle was known to the ancients under the name of Saros.
CYCLOID. A geometrical curve of the higher kind.
CYCLONE. See [Typhoon].
CYLINDER. The body of a pump; any tubular part of an engine.—Charge cylinder of a gun, is the part which receives the powder and ball, the remaining portion being styled the vacant cylinder. Especially in marine steam-engines, the cylindrical metal tube, with a diameter proportionate to the power of the engine, of which it may be termed the chief part, since it contains the active steam. Also, a cartridge box for the service of artillery. (See [Cartridge-box].)
CYLINDER-COVER. In the steam-engine, is a metal lid with a hole in the centre for the piston-rod to work through.
CYLINDER CROSS-HEAD. An adaptation on the top of the piston-rod, stretching out athwart the cylinder, from the ends of which the side-rods hang.
CYLINDER ESCAPE-VALVES. Small conical valves at each end of the cylinder, for the purpose of letting off any water that may collect above or below the piston.
CYLINDER POWDER. That made upon the improved method of charring the wood to be used as charcoal in iron cylinders. All British government gunpowder is now made thus.