John Wesley Powell, scientist and explorer of the American West, moved from New York to Jackson with his family in 1838 and lived there until 1846. He developed an early interest in geology from his tutor "Big" George Crookham, a Jackson salt boiler, educator, and abolitionist. Powell served in the Union Army during the Civil War and lost his right arm at Shiloh in 1862. Later he became professor of geology at Illinois Wesleyan University. In 1869, he led a nine-man expedition in the first exploration of the entire length of the Colorado River, providing the first scientific description of the Grand Canyon. Subsequently Powell helped found the U.S. Geological Survey and served as its director from 1881 to 1894. Late in the evening of July 16, 1863, Confederate General John Hunt Morgan entered Jackson with 2,000 cavalrymen and met no resistance. Finding many townspeople assembled, the raiders took the men prisoner and held them at the fairground, then foraged through the town, taking food and all available horses. They also burned the Cincinnati and Marietta Railroad depot and destroyed the office of The Standard, the Republican newspaper. Morgan made his headquarters at the Isham House before continuing eastward on the afternoon of July 17. Strongly divided politically during the Civil War, Jackson received no special consideration from Morgan, and both unionists and Copperheads suffered equally.