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Rodman, Thomas Jackson

Rodman, Thomas Jackson (1815–1871), U.S. Army officer and ordnance innovator.Born near Salem, Indiana, Rodman graduated seventh in his class at West Point in 1841. He entered the artillery. Distressed by the fatal bursting of the USS Princeton's flawed experimental “Peacemaker” cannon, he proposed in 1845 a novel system of casting smoothbore heavy ordnance. Unlike conventional castings, which cooled from the outside in, Rodman cast cannon on a hollow core, cooling from the inside out. As the outer layers cooled, they compressed the inner layers, giving the cannon greater tensile strength. After initially dismissing the idea, the army's Ordnance Bureau finally approved it in 1859. The United States and European nations immediately adopted it as the method of choice until the 1880s, when steel cannon became too large to cast in one piece. Rodman also introduced mammoth, perforated cake powders, whose larger grains burned more uniformly than earlier gunpowders. He published his work in Reports of Experiments on the Properties of Metals for Cannon, and the Qualities of Cannon Powder (1861). During the Civil War, while the Union army made a number of “Rodman guns,” Rodman himself supervised the government's Watertown Arsenal. He commanded the Rock Island Arsenal after the war and died on active duty, having reached the rank of brevet brigadier‐general.
[See also Artillery.]

Kurt Henry Hackemer

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