“And if we took their distances to the place where they left their canoes—that’s what they called Shoshoni Cove, where the river petered out for boats—we’d have three thousand and ninety-six miles; two hundred and forty-seven miles above here, as they figured it, and they weren’t at the summit even then. Now if we’d take their probable estimate, if they’d finished the distance to the real head of the Missouri, we’d have to allow them about thirty-two hundred and forty-nine miles plus their overrun, at least fifty miles.
“Yes, if they’d have gone to the real source, they’d have sworn it was over thirty-three hundred miles to St. Louis, and over forty-five hundred miles to the Gulf. The modern measurements make it forty-two hundred and twenty-one miles.
“So, young gentlemen, you can see that you are now coming toward the head of the largest continuous waterway in the world. It is five hundred miles longer than the Amazon in South America, and more than twelve hundred miles longer than the river Nile, in Africa.
“Now, Meriwether Lewis did not know as much about all these things as we do now, yet see how he felt about it, at his camp fire, not so far from here:
“‘The mountains do not appear very high in any direction tho’ the tops of some of them are partially covered with snow, this convinces me that we have ascended to a great hight since we have entered the rocky Mountains, yet the ascent has been so gradual along the vallies that it was scarcely perceptable by land. I do not believe that the world can furnish an example of a river runing to the extent which the Missouri and Jefferson’s rivers do through such a mountainous country and at the same time so navigable as they are. if the Columbia furnishes us such another example, a communication across the continent by water will be practicable and safe.’
“Class dismissed. I see Billy has got the horses.” The boys put away their maps and rolled their beds.
All of the party being good packers, it was not long before they had left their camp ground on the knoll and were off upstream once more, edging the willow flats and swinging to the ford of the Madison, which they made with no great danger at that stage of the water. Thence they headed back for the Jefferson fork, having by now got a good look at the great valleys of the Three Forks.
“Which way, sir?” asked Billy now of their leader. “Shall we stop at the real headquarters camp of the Three Forks, just about a mile up—where the Indian girl told them she had been taken prisoner when she was a child?”
“Too near town!” sung out Jesse, who overheard the question. “Let’s shake the railroad.”