RACORDEMENT, Fr. This word is derived from racorder, which, in French architecture, signifies to join two pieces of building on one surface, or to unite an old building with a new one.
RADE, Fr. Road for ships to ride in.
RADEAUX, Fr. Rafters. They are frequently used in sieges, for the purpose of crossing ditches, &c. Chevalier Folard enters largely into the nature of these rafters, particularly in his 4th volume, page 67.
RADIOMETER, (Radiomètre, Fr.) This instrument is sometimes called Jacob’s staff, bâton de Jacob. It is used by some to take the sun’s altitude, and by others to ascertain elevations at sea.
RADIUS, the semi-diameter of a circle. In fortification, the radius is distinguished into exterior, [interior], [oblique], and right radius. The three former are noticed each under its initial letter. The latter is a perpendicular line drawn from the centre of a polygon to the exterior side.
RAFFINAGE, Fr. a term used by the French to express the operation through which saltpetre passes after it has been boiled once. The literal meaning is refining; the act of cleansing any thing from recrementitious matter.
RAFFINER, Fr. To refine.
RAFFINOIR, Fr. a wooden cask, or copper vessel, in which saltpetre is deposited after it has been boiled once. It usually remains thirty minutes, after which it is let out through a cock fixed for that purpose at the bottom of the vessel.
RAFRAICHISSEMENS, Fr. Provisions. See [Quartier].
RAFRAICHIR, Fr. To cool; to spunge; as rafraichir le canon; to spunge a cannon.