By Matthew Keagle, Curator
Quite often it is bronze. Bronze, an alloy of roughly 90% copper and 10% tin (although exact alloys in the 18th century varied), was one of the two primary materials used to cast artillery in the early modern period. The task took considerable technical skill. Gun founders had to be able to manipulate thousands of pounds of molten metal into hollow molds to cast cannon that could then withstand the enormous pressure of many pounds of exploding gunpowder packed behind solid iron projectiles.Gun founders in the period were sought after tradesmen. Many used their technical skill across national borders. For example, Swiss founders regularly worked in France and Spain, while Dutch founders, trained by Swiss, worked in England.
The gun founder had to know the proportions of the alloy he was preparing for casting the cannon, just one part of the skill of his trade. Generally, raw copper and tin were added to the furnace to make bronze, however, many founders used condemned or captured cannon to recast into new pieces. Captured cannon could simply be turned against an enemy, but the different systems of artillery across Europe meant enemy cannon were not always that easily employed. For example, a Spanish 16-pounder did not fire the same sized shot as a French 16-pounder, since until the 1740s, they were based off of different systems of weight. The English didn’t even have a 16-pounder as part of their arsenal, meaning capture guns were useless unless captured with ammunition. Often the best use for captured cannon was to have them re-made into new ones.
Surirey de St. Remy’s Memoires d’Artillerie, first published in 1697, includes a plate depicting four men sawing a bronze 24-pounder cannon in half. A bronze 24-pounder, like two Spanish guns in Fort Ticonderoga’s collection, could weigh up to 6500 pounds – three and a quarter tons! Sawing such a massive piece in half was required to maneuver it into the furnace to be melted and re-made.
At least one Spanish 12-pounder in Fort Ticonderoga’s collection bears the phrase “Bronzes Viexos” on the face of its left trunnion. This translates as old bronze, indicating that this particular gun was cast by melting down old cannon. This could be important information as virgin bronze was deemed to be stronger. One wonders what old cannon were sacrificed to the gun founders furnace to cast this cannon in 1747.
See this recast cannon, and our two massive 24-pounders, at special events all winter as they keep silent sentinel on Lake Champlain.