in fortification, denote pieces of timber, about six inches square, placed at the lower end of the platform, next to the parapet, to prevent the wheels of the gun carriages from damaging the parapet.

HYDROGRAPHICAL Charts or Maps, more usually called sea-charts, are projections of some part of the sea, or coast, for the use of navigation. In these are laid down all the rhumbs or points of the compass, the meridians, parallels, &c. with the coasts, capes, islands, rocks, shoals, shallows, &c. in their proper places, and proportions.