 The caponier ( rifle gallery ) extends into the ditch between the rampart and glacis from the fort 's north west corner . It is connected to the fort via a tunnel , running under the rampart from the manning parade . For blast protection and <unk> the tunnel was built with a <unk> . The caponier has rifle firing ports and was originally protected from direct artillery fire by the glacis . Early plans showed the caponier extending from the fort 's south west , and a tunnel linking the magazine and southern guns . 
