Breach Patched with Gabions, North Wall

A breach in the north wall of Fort Sumter, and the repair is the subject.

The wall is broken through, and the gap has been filled with gabions — cylindrical wicker baskets, open at both ends, set in place and packed with sand and earth. The technique is far older than the war; military engineers had used gabions since the sixteenth century, because they can be woven on site out of whatever will bend, carried empty by one man, and filled where they stand.

What makes them worth looking at here is that they were better than the wall. Solid masonry shatters under rifled artillery: the shot arrives concentrated and the brick spalls and collapses. Sand does not shatter. It absorbs a projectile and closes around it. So the Confederates inside Sumter spent two years converting a masonry fort into an earthen one, filling their own ruins with the material that actually stopped shells.

This is the whole argument of Civil War fortification in a single frame — the moment when brick forts became obsolete, photographed at the place where it happened.