Part 153

Redoubt, is also the name of a small work, made sometimes in a bastion, and sometimes in a ravelin, of the same form.

Redoubt, is likewise a square work without any bastions, placed at some distance from a fortification, to guard a pass or to prevent an enemy from approaching that way.

Detached-redoubt, is a kind of work much like a ravelin, with flanks placed beyond the glacis: it is made to occupy some spot of ground which might be advantageous to the besiegers; likewise to oblige the enemy to open their trenches farther off than they would otherwise do. Their distance from the covert-way should not exceed 120 toises, that it may be defended by musquet shot from thence.

Redouts-en-cremaillere, so called from their similitude to a saw; the inside line of the parapet being broken in such a manner, as to resemble the teeth of a saw; whereby this advantage is gained, that a greater fire can be brought to bear upon the defile, than if only a simple face was opposed to it, and consequently the passage is rendered more difficult.

Retrenchment, in fortification, is any work raised to cover a post, and fortify it against an enemy, such as fascines loaded with earth, gabions, sand-bags, &c.

Revetement, in fortification, is a strong wall built on the outside of the rampart and parapet, to support the earth, and prevent its rolling into the ditch. When the revetement of a rampart goes quite up to the top, 4 feet of the upper part is a vertical wall of 3 feet thick, with a square stone at the top of it, projecting about 5 or 6 inches, and a circular one below, or where the slope begins, of 8 or 10 inches diameter. They go quite round the rampart, and the circular projection is called the cordon.

Rideau, in fortification, is a small elevation of earth, extending lengthways on a plane, and serving to cover a camp, or to give an advantage to a post. They are also convenient for the besiegers of a place, as they serve to secure the workmen in their approaches to the foot of a fortress.

Rideau is also used sometimes for a trench, the earth of which is thrown up on its sides, to serve as a parapet for covering the men.

Sap. See SIEGE.

Scarp, is, properly speaking, any thing high and steep, and is used in fortification to express the outside of the rampart of any work next to the ditch.

Sillon, in fortification, a work raised in the middle of a ditch to defend it when too broad. This work has no particular construction, but as it runs, forms little bastions, half moons, and redans, which are lower than the rampart of the place, but higher than the covert way. It is not much used at present.

Sillon means literally a furrow. In fortification, it is a work raised.

Swallow’s-tail, a kind of out-work, only differing from a single tenaille, in that its sides are not parallel as those of the tenaille, but narrower towards the town than towards the country.

Talus signifies a slope made either on the outside or inside of any work, to prevent the earth’s rolling down; it is of various denominations, viz.

Talus of the banquette is that gentle slope from the top of the banquette to the horizontal line.

Interior talus of the parapet, the slope from the top of the parapet to the banquette.

Talus of the top of the parapet, that slope which lessens the height of the parapet towards the berm, by which means the troops firing from the banquette can defend the covert way.

Exterior talus of the parapet, the slope of the parapet from the top to the berm.

Interior talus of the ditch, the slope from the top of the ditch to the bottom, within.

Tenailles are low works made in the ditch before the curtains; of which there are three sorts. The first are the faces of the bastion produced till they meet, but much lower; the second have faces, flanks, and a curtain; and the third have only faces and flanks. Their height is about 2 or 3 feet higher than the level ground of the ravelin. Their use is to defend the bottom of the ditch by a grazing fire, as likewise the level ground of the ravelin, and especially the ditch before the redoubt within the ravelin, which cannot be defended from any other quarter so well as from them.

Tenaillons are works made on each side of the ravelin, much like the lunettes; with this difference, that one of the faces in a tenaillon is in the direction of the ravelin; whereas that of the lunette is perpendicular to it.

Terre-pleine, in fortification, the horizontal superficies of the rampart, between the interior talus and the banquette. It is on the terre pleine that the garrison pass and repass; it is also the passage of the rounds.

Tower bastions are small towers made in the form of bastions; first invented by M. Vauban, and used in his second and third method; with rooms or cellars underneath, to place men and artillery in them. As these towers are almost a solid piece of masonry, they must be attended with great expence, though their resistance can be but little; for it has been found by experience, that the casemates are but of little use, because as soon as they have fired once or twice, the smoke will oblige the defenders to leave them, notwithstanding the smoke holes: hence it may be concluded, that the strength of these tower bastions does by no means answer their expences; and that, if small bastions were made instead of them, without casemates, they would be much better, and less expensive.

Traditore, in fortification, signifies the concealed or hidden guns in a fortification, behind the reverse of the orillon.

Traverse, in fortification, is a parapet made across the covert way, opposite to the saliant angles of the works, and near the places of arms, to prevent enfilades; they are 18 or 20 feet thick, and as high as the ridge of the glacis. There are also traverses made in the caponniers, but then they are called tambours.

Traverses are likewise made within other works, when there are any hills or rising grounds from whence the interior parts of these works may be observed. Traverses that are made to cover the entrances of redoubts in the field, need not be above 8 or 10 feet thick.

Trous-de-loup, or wolf holes, round holes made about 5 or 6 feet deep, with a stake in the middle: they are generally dug round a field redoubt, to obstruct the enemy’s approach; circular at top, and about 4¹⁄₂ feet diameter; pointed at the bottom like an inverted cone. Two or three rows of them are dug chequerwise, about 6 paces from the edge of the ditch, viz. two rows of holes exactly opposite to each other, and a third row in the middle, covering the intervals.

Wicket, a small door in the gate of a fortified place, at which a man on foot may go in, and which may be opened though the gate itself be kept shut.