Brigadier General Thomas J. Rodman was born on July 30, 1815 and graduated from the United States Military Academy in 1841.
Around 1844, he devised a theory to account for both internal strains and imperfections, and for variations in the density, hardness, and tensile strength of the metal in cast iron cannon.
During the period 1857 through 1859, he conducted experiments with cannons and the proper gunpowder formulations. This work resulted in his discovery of the progressive combustion principle and his findings that the rate of combustion could be controlled by compressing finely grained powder into larger grains of greater density.
In 1861, he devised a crusher gauge which successfully measured weapon internal pressure for the first time. His most outstanding contribution was the method he invented for cooling cannon castings.
The cannons were cast around hollow cores, through which the interior casting surfaces were cooled while the outer surface was kept hot both by heating and insulation. This method produced a gun wherein the inner layers were under considerable contraction, thus being very superior to the unchilled cast guns which so often burst during firing.
General Rodman died at Rock Island Arsenal, Illinois, on June 7, 1871.