"In the federal arsenal was an antique demiculverin of french manufacture "
16th century Demi-culverin
Creative Commons Attribution Share Alike16th century Demi-culverin - Credit: WyrdLight.com

Developed in the late 16th century, the demi-culverin was a medium-sized cannon often used in sieges for destroying walls and buildings.

Considered obsolete before the turn of the 20th century, that antique French demi-culverin was probably a remnant from the days of the French Intervention.