Page:A Brief History of South Dakota.djvu/36

 CHAPTER VI

selected to head his party of explorers his private secretary, Captain Meriwether Lewis, a cousin of George Washington. Scientific knowledge was not very far advanced in America at this time, but early in the spring of 1803, a few days before the bargain with Napoleon had been made and months before it had been thought of in America, Lewis hurried from Washington to Philadelphia to take a brief course in the natural sciences and mathematics, hoping to gain enough to enable him to make scientific observations of the country through which he was to pass, and to determine the latitude and longitude of various places.

While Lewis was in Philadelphia, it occurred to him that it would be wise to organize the expedition in two parts, and keep two records, so that in case one record was lost there would be hope of preserving the other. He told Jefferson about it, and the President thought the plan a wise one; so Captain William Clark—a brother of General George Rogers Clark, the man who in the Revolutionary War had saved Illinois, Indiana, and Ohio to the United States—was selected to accompany Captain Lewis, and to enjoy with him equal rank in the command of the enterprise. 30