The idea that America was but a projection of Asia possessed all the early explorers; and indeed it was a century and a half later (1728) before Bering sailed from the Pacific Ocean to the Arctic and proved that America was insulated. There was another geographical error, which took even a longer time to explode,--the notion that a waterway somewhere extended through the American continent, uniting the Atlantic and the Pacific. John Smith and other English colonists thought that by ascending the James, the York, the Potomac, the Roanoke, or the Hudson, they could emerge with ease upon waters flowing to the ocean of the west. Champlain sent (1634) the fur-trader Nicolet up the Ottawa River and the Great Lakes into Wisconsin, which he thought to be Asia; and Jolliet and Marquette (1673) imagined they had found the highway thither when their birch-bark canoes glided into the upper Mississippi at Prairie du Chien. One hundred and seven years before the Pilgrims landed at Plymouth Rock, Balboa scaled the continental backbone at Darien (1513), and in the name of Spain claimed dominion over the waters of the Pacific. With undaunted zeal did Spanish explorers then beat up and down the western shore of the Gulf of Mexico, vainly seeking for a passage through by water. A great stimulus had now been given to the general desire to reach India by sea; for the Turks were overrunning Egypt (1512-1520) and despoiling the caravans from the East, so that the manufactures and trade of western Europe were sadly crippled. But thus far Portugal alone held the key to the sea-route to India. 9. Spanish Exploration of the Interior (1513-1542). Sidenote: Ponce de Leon in Florida. This same year (1513) was notable also for the first visit made by Spaniards to the mainland of North America. Ponce de Leon, a valiant soldier worn out in long service, and who had been serving as governor of Porto Rico, went to the Florida mainland, where a popular legend said there was a fountain giving forth waters capable of recuperating life. The country was ablaze with brilliant flowers, but the elixir of life was not there, and he returned disappointed. Sidenote: Vasquez in South Carolina.