REDOUT is a general name for nearly every kind of work in the class of field fortifieations ; thus, a redan with flanks, a parapet enclosing a square or polygonal area, a work in the form of a star [STAR-Toni], and a fort with bastions at the angles, like the enciente of a fortress, are occasionally so called ; but the second of these is the work to which the terns is more particularly applied, and it is that which we propose now to describe.
When a work to be constructed on level ground is intended to contain troops and artillery for the purpose of preventing the enemy from occupying the spot, and when there is an equal probability that the work may be attacked on any side, that spot should be quite enclosed by the parapet ; also if the defence is to continue only till succour can arrive from the army in the vicinity, flanking defences being then scarcely necessary, a' quadrangular figure may suffice for the plan of the work, and there can be no reason why one side should be longer than another, or why the sides should form with each other any but right angles. But when the redout is to occupy an eminence whose figure on the plan is irregular, the faces of the work, whatever be the form thus produced, must necessarily be traced so as to corre spond to the different directions assumed by the brow of the height ; and if the fire of the work is intended to defend some fixed object, as a pass leading towards it, one of the faces must be perpendicular to the direction of that pass. It may be observed, however, that in general the number of faces, though not less than four, should be as few as possible. The ditches of all polygonal works without re-entering angles, are incapable of being defended by the fire from the above, on account of the height and thickness of the latter, which prevent the soldiers from seeing them ; and a curvilinear redout has, besides, two defects which are irremediable : the fires from its parapets are diverging, therefore they produce little effect while the enemy is advancing up to the work ; and the ditch, on account of its form, is incapable of being defended from stockades within it. These objections apply with nearly equal force to redouts formed on regular polygons of more than five or six sides. The French, however, made a circular redout of casks for the purpose of strengthening the defence of the isthmus at St. Sebastian, previously to the siege of that place in 1813;
and circular redouts of masonry are supposed to be useful on the sea coasts. In the latter situation they are not liable to be attacked by infantry ; and their artillery, which is mounted on traversing plat forms, may be fired in any direction against ships or boats, should an enemy attempt a debarkation of troops. [MARTELL° TOWERS.] Every work in field as well as in permanent fortification is surrounded by a ditch, from whence ie obtained the earth for the parapet, and by which the difficulty of carrying it by assault is increased. The ditch is generally crossed directly opposite the entrance by a bridge of timber, which should be capable of being drawn into the work, or re placed at pleasure. The entrance into a redout is at a re-entering angle, if there is one, otherwise it may be about the middle of one of the faces on the side which is least exposed to the view of the enemy ; and, besides being barricaded, it is defended by the fire from a traverse, which is raised in the interior, and perpendicular to the direction of the passage.
Redouts for the defence of positions' are in general intended to contain only about fifty men with three guns; but works in the form of irregular polygons have sometimes been constructed of a magnituie sufficient to contain 1600 men and twenty-five pieces of artillery ; and such were the two principal redouts (on Mount Agraea and at Torres Vedras) formed in 1810, in order to protect Lisbon. These were , expected to make a vigorous defence in the event of being attacked ; but it is admitted that their trace, or ground-plan, was defective on account of the want of flanks, and perhaps they would have been pre vented from falling only by the strong divisions of troops who were daily under arind in their vicinity. The redout constructed by the British in the neighbourhood of Toulon, in 1793, for the protection of the town and fleet, was a large work well furnished with artillery ; yet, on being attacked by the republican troops, it was taken, after a gallant resistance, in which the enemy was twice repulsed. The ditches being undefended by flanks, the assailants, on being driven into them, re-formed their order with little molestation ; and at the third attack they succeeded in getting possession of the work.