DAW-FISH. The Scyllium catulus, a small dog-fish.
DAWK-BOAT. A boat for the conveyance of letters in India; dawk being the Hindostanee for mail.
DAY. The astronomical day is reckoned from noon to noon, continuously through the twenty-four hours, like the other days. It commences at noon, twelve hours after the civil day, which itself begins twelve hours after the nautical day, so that the noon of the civil day, the beginning of the astronomical day, and the end of the nautical day, occur at the same moment. (See the words [Solar] and [Sidereal].)
DAY-BOOK. An old and better name for the log-book; a journal [Fr.]
DAY-MATES. Formerly the mates of the several decks—now abolished. (See [Sub-lieutenant].)
DAY-SKY. The aspect of the sky at day-break, or at twilight.
DAY'S WORK. In navigation, the reckoning or reduction of the ship's courses and distances made good during twenty-four hours, or from noon to noon, according to the rules of trigonometry, and thence ascertaining her latitude and longitude by [dead-reckoning] (which see).
D-BLOCK. A lump of oak in the shape of a D, bolted to the ship's side in the channels to reeve the lifts through.
DEAD-ANGLE. In fortification, is an angle receiving no defence, either by its own fire or that of any other works.
DEAD-CALM. A total cessation of wind; the same as flat-calm.