2. Clark was not actually a captain. When Lewis asked Clark to join the expedition he said President Jefferson was willing to promote him to captain. Before the expedition began, the Secretary of War notified Lewis that Clark would receive a lieutenant's title. Lewis was angered and wrote Clark that it was best that none of their party or any other persons would know anything about the grade which "By God, shall be equal to my own."
3. Clark would establish a reference point, a landmark determined by latitude and longitude. From that point, he would take a reading with the sighting