These arrangements being completed, Captain Clarke took charge of the canoes; while Captain Lewis, with four men, proceeded by land, in hopes of soon putting it beyond a doubt that the river which they were now ascending was the Missouri. The decisive proof was to be sought in its falls, which the Indians had described as not remote from the Rocky Mountains, and as of remarkable grandeur. Captain Lewis passed along the direction of the river, during two days, and, on the next day, found himself in a position which overlooked a most beautiful plain. Finding that the river here bore considerably to the south; and fearful of passing the falls before he reached the Rocky Mountains, he now changed, his course towards the south, and, leaving these hills to the right, proceeded across the plain. In this direction he had gone about two miles, when his ears were saluted with the agreeable sound of a fall of water; and, as he advanced, a spray, which seemed to be driven by the high south-west wind, arose above the plain, like a column of smoke, and vanished in an instant. Towards this point he directed his steps; and the noise, increasing as he approached, soon became too tremendous to be mistaken for any thing but the _Great Falls of the Missouri_. Having travelled seven miles after he first heard the sound, he at length reached the falls. The hills became difficult of access, and were two hundred feet high. Down these he hurried with impatience; and, seating himself on some rocks under the centre of the falls, he enjoyed the sublime spectacle of this stupendous object; which, since the creation of the world, had been lavishing its magnificence on the desert, unknown to civilization. For ninety or a hundred yards from the left cliff, the water falls in one smooth, even sheet, over a precipice of at least eighty feet. The remaining part of the river precipitates itself with a more rapid current; but, being received, as it falls, by the irregular and somewhat projecting rocks below, it forms a splendid prospect of perfectly white foam, two hundred yards in length, and eighty yards in perpendicular elevation. This spray is dissipated into a thousand shapes, sometimes flying up in columns fifteen or twenty feet high; and then being oppressed by larger masses of white foam, which exhibit all the brilliant colours of the rainbow.