DescriptionCast Iron 21-in signal cannon or swivel gun. During the American Revolution, 21-inch signal cannons were part of a category of small-scale artillery used for communication, defense, and signaling. These compact pieces, often referred to as swivel guns or signal guns, were essential for naval vessels, frontier forts, and field maneuvers. The cannon was found on the grounds of 155 Millburn Avenue (The Hessian House). It is highly likely that it saw action in the defense of the Vauxhall Bridge. Ogden’s First NJ and Harry Lee’s light cavalry/dragoons may have used this on the field of battle.