Embrasure

In fortification, is an opening in the parapet, or a hole in the mask wall of a casemate through which the guns are pointed. The sole or bottom of the embrasure is from 2 1 ⁄ 2 to 4 feet (according to the size of the gun) above the platform upon which the gun stands. Parapet embrasures are smallest at the interior opening, which is called the mouth, and is from 1 1 ⁄ 2 to 2 feet wide. The widening of the embrasure is what is called the splay . The sole slopes downward about one in six. Its exterior line, or its intersection with the exterior slope, is usually made half the length of the sole. The line which bisects the sole is called the directrix . The sides are called cheeks. The ma es of earth between embrasures are called merlons . When the directrix makes an angle with the direction of the parapet, the embrasure is oblique . The embrasures of casemates have in horizontal section a shape something like an hour-gla . The nearest part is called the throat. This is sometimes closed with iron shutters.