,
Belgium. Originally the term referred to a covered passageway that traversed the
ditch outside the curtain of a
fortress. Fire from this point could cover the ditch beyond the
curtain wall to deter any attempt to storm the wall. Thus the passageway was equipped with musket ports and
cannon ports that fired along the ditch. While fortifications were evolving to the simpler
polygonal style, the term was sometimes used to describe the flanking positions set at the corners of the ditch that provide the same function in that style of fort, especially in France. In bastioned forts, it usually takes the form of a low open passage, often partly sunken into the floor of the ditch and projecting outward into and across it, with access from the main fortress via a passage through the curtain wall. The roof, if any, was often made against weather, observation and small arms fire, not artillery. As polygonal fortresses evolved, caponiers became more substantial, higher and protected above from plunging fire with masonry and earth cover. In late 19th century, works which were largely underground, caponiers were reached via a tunnel from within the fort. ==Equipment==