Jack Sumner

John Colton Sumner (1840–1907) was an American explorer who took part in the Powell Geographic Expedition of 1869. An experienced marksman and boatman, he was chosen by John Wesley Powell to lead the first boat of the expedition. He eventually had a falling out with Powell over differences in personality, and was troubled through the rest of his life over the disappearance and deaths of three other men in the expedition. His remorse and resentment became so great that, in 1902, he castrated himself.