Case 16: New Forms
Although the principles of fortification advocated by Vauban would remain in use well into the 19th century, the 1790s and the era of the French Revolution marked the appearance of imaginative new fortification configurations that were less dependent on the bastion. Heavily armed, multi-tiered towers constructed of masonry or brick became popular as seacoast defenses. These were still often enclosed by a ditch, but the positions from which the ditch was defended increasingly took the form of underground galleries or covered structures called “caponnieres” that projected into the ditch and offered sheltered flanking positions for defending troops.
The “classic century of military engineering” was a time of much fortification building in America. The plans that survive document their design, construction, use, and destruction and offer tangible glimpses of 18th-century military architecture.
George F. Sproule (1741-1817), “A Plan of Louisbourg Survey’d and Drawn for his Excellency the Honble. Major General Thos. Gage Commander in Chief of His Majesty’s Forces in America.” Watercolor, pen and ink and pencil, . Thomas Gage Papers. Map Division, Maps 4-C-20.
George Sproule’s dramatically detailed plan of Louisbourg documented the extent of the devastation caused when British engineers intentionally mined and blew up the town walls in 1760. This was done in case France regained the place in peace negotiations. What had once been one of America’s most sophisticated fortress towns soon withered away leaving only earth and stone ruins.
Although the British had destroyed its defenses, they planned to maintain a token garrison at Louisbourg. Sproule’s plan projects a small fortification incorporating one of the original bastions. A plan of it is drawn on a paper flap that can be lifted to reveal the actual condition of that part of the defenses.
“Redoubt for 250 Men, four 24 pounders, 1 Howitzer and two Caronades.” Pen and ink, ca. 1803. Eyre Coote Papers. Map Division, Maps 8-N-8a.
This plan for a redoubt to defend Galway, Ireland, incorporates some of the elements of fortification that would become increasingly popular as the 19th century progressed. The round tower mounted the fort’s heaviest guns, and defense of the ditch relied on soldiers in the long, narrow, fully covered caponniere. The structure is pierced with loopholes from which they could fire on attackers.