Hoarding, wooden gallery which in time of war was put outside crenelations to enable the defenders to see the foot of the ramparts and towers, and to throw stones and materials of all kinds upon assailants attempting to approach.
List, interval left between the exterior defences and those of the body of the place (see p. [180]).
Machicoulis—The wooden hoarding being easily set on fire, it was replaced in France, about the end of the thirteenth century, by stone corbels carrying a crenelation of masonry, and leaving intervals between them for throwing materials upon the assailants who approached the foot of the walls. In Syria, the Christians had adopted the machicoulis as early as the beginning of the thirteenth century.
Mangonel, engine for propelling large stones from a kind of sling attached to the longer arm of a movable beam heavily weighted at its other extremity.
Merlon, solid space in the parapet between two embrasures. During the Middle Ages the merlons were usually perforated in the middle by a loop-hole. In time of war the battlements were masked by mantelets of wood, which could be raised at discretion by means of an axle turning in two iron collars let into the upper angles of the merlons.
Movable Tower, timber tower which was mounted on rollers and was advanced to the walls for the purpose of assault. The movable towers were made to command the battlements, and the upper story was furnished with a bridge which fell upon the crest of the ramparts of the towers (see p. [218]).
Oiseau, in the fifteenth and sixteenth centuries, a small masonry work which, disposed at the salient angles in the ditch, swept the latter and was intended to bar the passage. The oiseaux were masked by the counterscarp. In modern polygonal fortifications this plan has been re-adopted (see p. [373]).
Oppidum (Latin), a citadel or fortified strategical position, among the Gallic populations. Many Roman camps were formed at the epoch of the conquest of Gaul, on the Gallic oppida, which were only a kind of intrenched camps formed upon elevated plateaux. Several of our French towns occupy the sites of ancient oppida—Langres, Laon, Béziers, Carcassone, Uzerche, Sainte-Reine (Alesia), Le Puy-en-Velay, Semur-en-Auxois, Avalon, Puy d'Issolu, &c.
Orillon, projecting part of faces of bastions, intended to mask the flanks and to shield the guns which arm these flanks (see p. [280]).
Parados, mound of earth disposed behind the guns in battery, to shelter them as well as the servers from reverse firing.