1780 - David Thompson arrives in Americas

          The greatest map making astronomer of his era, David Thompson, arrives at a trading post near Hudson's Bay after a grueling four month voyage from England.  Thompson was taken on as an apprentice by the Hudson Bay Company because he was a precocious 14 year-old orphan with a natural aptitude for mathmatics.  During his first long winter at the outpost on Hudson's Bay, Thompson was taught the arts of celestial naviagtion, astonomy, and geography - skills that soon launched his legendary career mapping the wilderness of the American West.  Eventually, he located the headwaters of the Columbia River basin, a network of wild, mountainous rivers that covered an area the size of France.