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.