The appreciation of the dangers was doubtless quickened by the very first experience of the men as they left Corn Island in their boats - that of shooting the Falls of the Ohio, which was a feat by no means free from risk; and as if all things conspired to breed awe, an almost total eclipse of the sun cast its weird gloom over the visible world while the hazardous trip was mad down the boiling rapids; which, as Clark, says, "Caused various conjectures among the superstitious."

Whatever the effect on the superstitious, however, it nowise deterred the expedition, which from the moment of starting proceeded with a vigor and clarity that was well symbolized by that preliminary rush down the rapids, the journey down the river being pushed day and night by relays of oarsmen. Fearful of the strength of Vincennes and mingling caution with his courage, Clark resolved to first attack the settlements on the Mississippi River, the reason being that he might, in case of reverse, escape into Spanish territory across the river; or, if successful, he might, as he expressed it, "pave our way to the possession of Post St. Vincent." The first objective point was Kaskaskia, on the Mississippi, in what is now Randolph County, Illinois, and in order to avoid detection in the approach, the plan was to debark before reaching the Mississippi and march across country northwestward, a distance of one hundred and twenty miles.