By the 18th of October, fifteen canoes were completed, and on the following day the party embarked with their effects; leaving their horses grazing about the banks, and trusting to the honesty of the two Snakes, and some special turn of good luck for their future recovery.

The current bore them along at a rapid rate; the light spirits of the Canadian voyageurs, which had occasionally flagged upon land, rose to their accustomed buoyancy on finding themselves again upon the water.  They wielded their paddles with their wonted dexterity, and for the first time made the mountains echo with their favorite boat songs.

In the course of the day the little squadron arrived at the confluence of Henry and Mad Rivers, which, thus united, swelled into a beautiful stream of a light pea-green color, navigable for boats of any size, and which, from the place of junction, took the name of Snake River, a stream doomed to be the scene of much disaster to the travellers.  The banks were here and there fringed with willow thickets and small cotton-wood trees.  The weather was cold, and it snowed all day, and great flocks of ducks and geese, sporting in the water or streaming through the air, gave token that winter was at hand; yet the hearts of the travellers were light, and, as they glided down the little river, they flattered themselves with the hope of soon reaching the Columbia.  After making thirty miles in a southerly direction, they encamped for the night in a neighborhood which required some little vigilance, as there were recent traces of grizzly bears among the thickets.

On the following day the river increased in width and beauty; flowing parallel to a range of mountains on the left, which at times were finely reflected in its light green waters.  The three snowy summits of the Pilot Knobs or Tetons were still seen towering in the distance.  After pursuing a swift but placid course for twenty miles, the current began to foam and brawl, and assume the wild and broken character common to the streams west of the Rocky Mountains.  In fact the rivers which flow from those mountains to the Pacific are essentially different from those which traverse the prairies on their eastern declivities.  The latter, though sometimes boisterous, are generally free from obstructions, and easily navigated; but the rivers to the west of the mountains descend more steeply and impetuously, and are continually liable to cascades and rapids.  The latter abounded in the part of the river which the travellers were now descending.  Two of the canoes filled among the breakers; the crews were saved, but much of the lading was lost or damaged, and one of the canoes drifted down the stream and was broken among the rocks.