Batardeau

in fortification, is a ma ive perpendicular pile of masonry, whose length is equal to the breadth of the ditch, inundation, or any part of a fortification where the water cannot be kept in without the raising of these sorts of works, which are described either on the capitals prolonged of the bastions or half-moons, or upon their faces. In thickne it is from 15 to 18 feet, that it may be able to withstand the violence of the enemy’s batteries. Its height depends upon the depth of the ditch, and upon the height of the water that is nece ary to be kept up for an inundation; but the top of the building must always be under the cover of the parapet of the covert way, so as not to be exposed to the enemy’s view. In the middle of its length is raised a ma ive cylindrical turret, whose height exceeds the batardeau 6 feet.