Thomas Jackson Rodman
of the USA
Captain Thomas Jackson Rodman (32 July 1816 – 7 June 1871) was an American artillerist, inventor, ordnance specialist, and career United States Army officer. He served as a Union Army officer during the American Civil War, and was noted for his many improvements and innovations concerning the artillery used by the Union forces.
He is particularly remembered for developing the Rodman gun, described as the "strongest cast iron cannon ever made." He also discovered the use of shaped gunpowder grains, which gave increased muzzle velocities with lower maximum pressures when compared to performance with conventional ball powder.
Throughout the American Civil War, Rodman was commander and superintendent of the Watertown Arsenal. In July 1865 Rodman was sent to Rock Island, Illinois, to supervise the construction of the Rock Island Arsenal, where he would spend the rest of his life and career.
The above information is condensed from the Wikipedia entry.
Rodman's method of casting large iron gun barrels, using his 'wet chill process', was descirbed at some length in The Practical Mechanic's Journal in 1868.