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. CYPHERING. A term in carpentry. (_See_ SYPHERED.) D. D. In the _Complete Book_, D means dead or deserted; Dsq., discharged from the service, or into another ship. DAB. The sea-flounder. An old general term for a pleuronect or flat fish of any kind, but usually appropriated to the _Platessa limanda_. The word is familiarly applied to one who is expert in anything. DABBERLACK. A kind of long sea-weed on our northern coasts. DAB-CHICK. The little grebe, _Podiceps minor_. A small diving bird common in lakes and rivers. DACOITS. _See_ DEKOYTS. DADDICK. A west-country term for rotten-wood, touch-wood, &c. DAGEN. A peculiar dirk or poignard. DAGGAR. An old term for a dog-fish. DAGGER-KNEE. A substitute for the hanging-knee, applied to the under side of the lodging-knee; it is placed out of the perpendicular to avoid a port-hole. Anything placed aslant or obliquely, now generally termed diagonal, of which, indeed, it is a corruption. DAGGER-PIECE, OR DAGGER-WOOD. A timber or plank that faces on to the poppets of the bilge-ways, and crosses them diagonally, to keep them together. The plank securing the head is called the daggerplank. DAGGES. An old term for pistols or hand-guns. DAHLGREN GUN. A modification of the Paixhan gun, introduced into the United States service by Lieut., now Admiral, Dahlgren, of that navy; having, in obedience to the results of ingenious experiment on the varying force of explosion on different parts of a gun, what has been called the soda-water bottle or pear-shaped form. DAHM. An Arab or Indian decked boat. DAILY PROGRESS. A daily return when in port of all particulars relative to the progress of a ship's equipment. DAIRS. Small unsaleable fish. DALE. A trough or spout to carry off water, usually named from the office it has to perform, as a pump-dale, &c. Also, a place forward, to save the decks from being wetted, now almost abolished.