The Corps of Discovery Expedition set out in 1804, directed by President Thomas Jefferson to survey the United States’ newly acquired Louisiana Purchase. The exploration forms a core piece of early U.S. history. Picture a scene from the journey: It’s a cool morning, the silence punctuated by birdsong and the rustle of the breeze through the cottonwood trees. To one side, Commander William Clark, his rifle leaning against a plum tree and his rucksack nearby, squats over a latrine pit,…