Glacis

[Fr., from L. Lat. glatia, po ibly from Ger. glatt, smooth, or from Lat. glacies, ice, from its smoothne .] A place rendered slippery by wet falling on it, and being frozen over. - An easy, insensible slope. (Fort.) The inclined plane or slope that extends from the exterior of the covered way towards the open country (see Fig. 749). The crest of the glacis is about seven or eight feet above the terreplein of the covered way, which coincides with the natural level of the soil surrounding the fortifications. The slope itself extends about 150 feet from the covered way, having an inclination of one foot in twenty, or thereabouts, from the crest of the work to the natural surface of the ground. The glacis covers the masonry or rivetments of that part of the rampart which forms the scarp of the ditch, and serves to hide it from the batteries of the enemy. It also conceals soldiers who are in the covered way from the view of the investing force, and protects them from their fire. A banquette is usually constructed in the covered way at the foot of the interior of the glacis, which enables the besieged to pour a fire of musketry from thence on any party engaged in the construction of field-works and approaches, or advancing to the a ault of the fortre .