ou they had
luck--luck and judgment and the Indian girl. Sacagawea kept telling them
this was her country; that her people were that way--west; that they'd
get horses. For that matter, there were strong Indian trails, regular
roads, coming in from the south, north and west; but it wasn't quite
late enough for the Indians to be that far east on the fall buffalo hunt
at the Great Falls. It took them more than a month to figure out the
trail from here to the top. But if they had started south, down the Red
Rock----"

"Tell me about that, Billy."

"We're working too hard before breakfast, son! Go get the others up
while I fry these eggs. If we don't get off the Fort Rock and on our
way, somebody'll think we're crazy, camping up here."

Soon they were all sitting at breakfast around the remnants of the
little fire, and after that Billy went after the horses while the others
got the packs ready.

Jesse was excitedly going over with Rob and John some of the things
which Billy had been saying to him. Uncle Dick only smiled.

"First class in engineering and geography, stand up!" said he, as he
seated himself on his lashed bed roll. The three boys with pretended
gravity stood and saluted.

"Now put down a few figures in your heads, or at least your notebooks.
How high up are we here?"

"Do you mean altitude, or distance, sir?" asked Rob.

"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.