RECTIFIER. An instrument used for determining the variation of the compass, in order to rectify the ship's course, &c. It consists of two circles, either laid upon or let into one another, and so fastened together in their centres that they represent two compasses, the one fixed, the other movable; each is divided into 32 points of the compass, and 360°, and numbered both ways from the north and the south, ending at the east and west in 90°. The fixed compass represents the horizon, in which the north and all the other points are liable to variation.
REDAN. The simplest form of regular fortification, consisting of two faces meeting in a salient angle; generally applied in connection with other works.
REDD. The spawn of fish. Also, the burrow scooped out by salmon in which to deposit their ova.
REDD-FISH. A northern general term for fishes in the spawning state, but particularly applied to salmon.
REDEMPTIONER. One who purchases his release from obligation to the master of a ship, by his services; or one whose services are sold to pay the expenses of his passage to America or elsewhere.
REDHIBITION. An action to annul or set aside a contract of sale.
RED-HOT BALLS. Shot made red-hot in a furnace, and in that state discharged at the enemy. The loading is managed with wet wads.
REDOUBT. An inclosed work, differing from a fort, in that its parts do not flank one another.
RED PINE. Pinus rubra, the red spruce; the timber of which is preferred throughout the United States for yards, and imported for that purpose into Liverpool from Nova Scotia.
REDUCE, To. To degrade to a lower rank; or to shorten the allowance of water or provisions.