“I mean both. Well, I’ll tell you. Our altitude here is four thousand and forty-five feet. That’s twenty-five hundred and twenty feet higher than the true head of the Mississippi River—and we’re not to the head of the Missouri by a long shot, even now.
“And how far have we come, say to the Three Forks, just above here?”
“That’s easy,” answered John, looking at his book. “It’s twenty-five hundred and forty-seven miles, according to the last river measurements; but Lewis and Clark call it twenty-eight hundred and forty-eight miles.”
“That’s really of no importance,” said Uncle Dick. “The term ‘mile’ means nothing in travel such as theirs. The real unit was the day’s work of ‘hearty, healthy, and robust young men.’ One set of figures is good as the other.
“Still, it may be interesting to see how much swifter the Missouri River is than the Father of Waters. From the Gulf of Mexico to the source of the Mississippi is twenty-five hundred and fifty-three miles. Up our river, to where we stand, is just six miles short of that, yet the drop is more than twenty-five hundred feet more. One drops eight and a quarter inches to the mile, and the other nineteen inches to the mile.
“But understand, we’re talking now of the upper thread of the Mississippi River, and of the Three Forks of our river—which isn’t by any means at its head, even measuring to the head of the shortest of the three big rivers that meet here. Now, add three hundred and ninety-eight miles to twenty-five hundred and forty-seven miles. See what you got?”
“That’s twenty-nine hundred and forty-five miles!” exclaimed John. “Is it that far from the head to St. Louis?”
“Yes, it is. And if you took the Lewis and Clark measurements to the Forks it would be thirty-two hundred and forty-seven miles.