Vespucci

David Burgess brought an information-packed lecture on the life and accomplishments of Amerigo Vespucci. I had been led to believe that he was a minor figure in the charting of the New World. The fact that two continents were named for him was just a historical accident. According to Burgess, though, Vespucci figured much more prominently as a cartographer than I had been led to believe and actually discovered the concept of longitude. It took another three centuries to develop a chronometer sufficiently accurate to measure longitude, but Vespucci developed the idea based on a conjunction of Mars and the moon. His almanac told him precisely when the astronomical event would be visible in Seville. He observed it five hours and thirty minutes later at his location near present-day Brazil. The difference in the time of the conjunction gave him the idea of longitude. His maps, and those that followed his, were infinitely more accurate in depicting the shapes and distances of land masses on all maps.Read more