OF SOME OF THE TECHNICAL TERMS USED IN THIS BOOK.

Agger (Latin), terrace, or platform, which the Romans raised before the fronts attacked, for the purpose of setting up their projectile machines, securing a commanding position, and masking the troops assembled for an assault.

Bailey, fore-court; court of the outer works, or yard. The stables and the lodgings for the garrison were usually disposed in the bailey of the strong castles of the Middle Ages (see p. 169).

Balista (Latin, onager), an engine for propelling stones, worked by means of strongly-twisted cords.

Barbican, exterior defence protecting an entrance, and allowing a large assemblage of men to prepare for sorties, or to protect a retreat. Barbicans were either of masonry or earth, or constructed of a simple palisade. They were always of a circular form (see p. 169).

Bastion, an earthwork, cased externally with masonry, salient beyond the main body of the fortress, and possessing two faces, two flanks, and a gorge, so as to sweep the ground without, to cross the fires, and to flank the curtains. The gorge of bastions is open, closed, or retrenched. Bastions are said to be full when their terre-plein is level with the curtains; empty, when their terre-plein is beneath that level; armed with a cavalier, when upon their terre-plein is raised a battery of earth which commands the country without over the parapets (see p. 278, 310).

Boulevard, an earthwork—in use at the time when fire artillery had attained a certain degree of importance—for placing cannon outside ancient defences still preserved. Boulevards were of all forms—square, circular, and triangular (see p. 229).

Braie, an exterior defence of trifling height, protecting the foot of the ramparts, and hindering the enemy's approach.

BretÈche, timber construction intended to strengthen and to flank a front or a salient (see p. 184).

Cat, timber gallery, low and long, covered with a longitudinal very pointed and strongly ironed roof. Placed on wheels, these galleries were advanced to the foot of the walls, after the ditch was filled up, and enabled the miners to begin working into the masonry under cover. The name rat was given to these galleries in some provinces.

Catapult, engine for shooting large darts by means of a powerful bow.

Cavalier, earthwork raised in the middle of a bastion, or upon any point of the defence, to command the exterior. In the sixteenth century the besieging armies erected cavaliers around defences to mount cannon upon them. Our siege batteries are the modern analogues of these works (see p. 237, 312).

Chemise, exterior inclosure of a donjon; the chemise of the donjon consists of a wall which leaves a space of some yards between it and the donjon. A postern with a drawbridge gives a communication between one of the rooms of the donjon and the rampart walk of the chemise (see p. 201).

Clavicula (Latin), exterior defence, raised outside the gates of a camp, and which obliged those who endeavoured to enter to present their flank to the defenders of the ramparts (see p. 92).

Covered Way, road formed on the counterscarp and protected by the relief of the glacis (see p. 308).

Counterscarp, is the casing of the ditch which is opposite to the defence.

Demi-lune, low work, disposed before a curtain between two bastions, separated from the main body of the fortress by a ditch, and possessing two faces and two short flanks (see p. 306).

Donjon or Keep, chief retreat of the defenders of a strong castle. The donjon was always separated from the defences of the castle, and put in direct communication with the exterior (see p. 169).

Escarp is that part of a revetment of fortifications which fronts the exterior, from the bottom of the ditch to the parapet or crenelation.

Fausse-Braie, palisade or trench, with parapet, defending the bottom of the ditch, low enough to be masked by the relief of the counterscarp.

Glacis, sloping ground which extends from the counterscarp of the ditch towards the country, and masks the covered ways as well as the escarp.

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.

Parallel, trench parallel to the sides of the polygon of a fortress, supplying a covered communication for planting and serving the siege batteries. Formerly these parallels were required for approaching and planting the breach batteries. These parallels communicated with each other by trench boyaux traced in zigzags, so as not to be raked by the fires of the place (see p. 330).

ParÉclat, epaulment of earth, or formed with gabions raised on the ramparts, or in the middle of bastions, to shelter the defenders from the splinters of bombs and shells.

Place d'Armes, space defended by an epaulment, intended to enclose a body of men and to protect it from projectiles (see pp. 288, 308).

Postern, secondary gate, small gate, generally masked (see p. 170).

Rampart, epaulment raised with the earth taken from the ditch sunk on the outer side; also a wall crowned with a parapet and rampart walk. It signifies a permanent defence.

Ravelin, name originally given to demi-lunes. A work consisting of two faces, open at the gorge, low, and intended to sweep the exterior between two bastions (see p. 279).

Redan, work presenting a salient angle and a re-entering angle (see p. 306).

Retrenchment, a work made to augment the defensive strength of a place within the permanent fortifications, so as to present a fresh obstacle should the latter fall into the power of the enemy; the retrenchment consists of an epaulment of earth raised with the material from the ditch sunk on the outside.

Stimulus (Latin), barbed iron crook, which, fixed on a short stake stuck in the ground or in the bottom of conical holes, protected the approaches of a defence (see p. 80).

Tenaille, work consisting of a curtain having at each extremity two demi-bastions (see pp. 278, 306).

Traverse, a mound of earth disposed across covered ways, terre pleins, bastions, and curtains, to shield the guns and the defenders against enfilade, oblique, or ricochet fire (see p. 335).

Trebuchet, engine for propelling large stones, very similar to the mangonel, but whose counterpoise was suspended from the beam instead of being fixed to it.

Trench, road sunk in the ground, the earth being thrown up on one side only, or on both sides, for enabling the approach of places under cover.

Trench-shelter, temporary defence, consisting of an exterior epaulment made with the earth taken from a trench, in a way to shield the soldiers upon a front, around a camp or a post, and enable them to fire under cover. The trench-shelter is destined to play an important part since fire-arms have acquired a long range and a rapid discharge. The Romans, in their day, made use of trench-shelters in the field.

Vinea (Latin), a wooden mantlet, also a timber gallery, set up perpendicularly to the agger, and which affords approach to the platform under cover. The wooden towers intended to attack the ramparts of the besieged were rolled forward on these wooden galleries (see p. 83).

THE END.