"Persuaded," says the narrative, "of the necessity of securing horses to cross the mountains, it was determined that one of us should proceed ... till he found the Shoshones, ... who could assist us in transporting our baggage." Captain Lewis with three men preceded, and on August 11, saw "with the greatest delight a man on horseback, at the distance of two miles, coming down the plain toward them. On examining him with the glass, Captain Lewis saw that he was armed with a bow and a quiver of arrows; mounted on an elegant horse without a saddle, and a small string attached to the under jaw answered as a bridle. Convinced that he was a Shoshonee, and knowing how much of our success depended on the friendly offices of that nation, Captain Lewis was full of anxiety to approach without alarming him, and endeavor to convince him that he was a white man. He therefore proceeded on towards the Indian at his usual pace; when they were within a mile of each other the Indian suddenly stopped, Captain Lewis immediately followed his example, took his blanket from his knapsack, and holding it with both hands at the four corners, threw it above his head and unfolded it as he brought it to the ground, as if in the act of spreading it. This signal, which originates in the act of spreading a robe or skin as a seat for guests to whom they wish to show a distinguished kindness, is the universal sign of friendship among the Indians on the Missouri and Rocky Mountains." Unfortunately, the brave took alarm at the movement of Lewis's companions and fled. The next day brought them to the head-waters of the Jefferson. Here, "from the foot of one of the lowest of these mountains, which rises with a gentle ascent for about half a mile, issues the remotest water of the Missouri. They had now reached the hidden sources of that river, which had never yet been seen by civilized man; and as they quenched their thirst at the chaste and icy fountain--as they sat down by the brink of that little rivulet, which yielded its distant and modest tribute to the parent ocean, they felt themselves rewarded for all their labors and all their difficulties." Pushing on they soon saw, to the west, high, snow-topped mountains.