in the morning sun.  One can guess how the weather-bronzed, ragged man paused to gaze on the glimmering summits.  Only one other explorer had ever been so far west in this region—­young De la Verendrye, fifty years before; but the Frenchman had been compelled to turn back without crossing the mountains, and the two Americans were to assail and conquer what had proved an impassable barrier.  The Missouri had become too deep for poles, too swift for paddles; and the banks were so precipitous that the men were often poised at dizzy heights above the river, dragging the tow-line round the edge of rock and crumbly cliff.  Captain Lewis was leading the way one day, crawling along the face of a rock wall, when he slipped.  Only a quick thrust of his spontoon into the cliff saved him from falling almost a hundred feet.  He had just struck it with terrific force into the rock, where it gave him firm handhold, when he heard a voice cry, “Good God, Captain, what shall I do?”

[Illustration:  Tracking Up-stream.]

Windsor, a frontiersman, had slipped to the very verge of the rock, where he lay face down with right arm and leg completely over the precipice, his left hand vainly grabbing empty air for grip of anything that would hold him back.  Captain Lewis was horrified, but kept his presence of mind; for the man’s life hung by a thread.  A move, a turn, the slightest start of alarm to disturb Windsor’s balance—­and he was lost.  Steadying his voice, Captain Lewis shouted back, “You’re in little danger.  Stick your knife in the cliff to hoist yourself up.”

With the leverage of the knife, Windsor succeeded in lifting himself back to the narrow ledge.  Then taking off his moccasins, he crawled along the cliff to broader foothold.  Lewis sent word for the crews to wade the margin of the river instead of attempting this pass—­which they did, though shore water was breast high and ice cold.

[Illustration:  Typical Mountain Trapper.]

The Missouri had now become so narrow that it was hard to tell which was the main river and which a tributary; so Captain Lewis and four men went in advance to find the true course.  Leaving camp at sunrise, Captain Lewis was crossing a high, bare plain, when he heard the most musical of all wilderness sounds—­the far rushing that is the voice of many waters.  Far above the prairie there shimmered in the morning sun a gigantic plume of spray.  Surely this was the Great Falls of which the Indians told.  Lewis and his men broke into a run across the open for seven miles, the rush of waters increasing to a deafening roar, the plume of spray to clouds of foam.  Cliffs two hundred feet high shut off the view.  Down these scrambled Lewis, not daring to look away from his feet till safely at bottom, when he faced about to see the river compressed by sheer cliffs over which hurled a white cataract in one smooth sheet eighty feet high.  The spray tossed up in a thousand bizarre shapes of wind-driven clouds.  Captain Lewis drew the long sigh of the thing accomplished.  He had found the Great Falls of the Missouri.