Battle of Fort Sumter Online Exhibit
An Embrasure at Sumter (Inside View)
Caption: An Embrasure at Sumter – Inside – (Drawn by an officer of Major Anderson's command)
Source: Illustration from Harper's Weekly, March 16, 1861, page 164.
Note: Another illustration in the same issue of Harper's Weekly showed an exterior view of an embrasure.
In military terms, an embrasure is an opening in a fortification that allows a weapon to be fired out, while those manning it remain protected behind the wall.