1743-1826 1763-1848 19thcentury activities ambition american-west americanhistory astor astoria biologicalsciences columbia-river discoveries discoveriesingeography discoveryandexploration early-american-frontier expeditions exploration fur-trade general health history jefferson john-jacob-astor johnjacob lewis-and-clark-expedition lost-pacific-empire manifest-destiny native-americans nutrition outdoorskills pacific-northwest pacific-ocean socialsciences sports survival thomas thomas-jefferson westward-expansion