“But the Journal makes it eighteen hundred and eighty-eight miles to the mouth of the Yellowstone. My steamboat records call it seventeen hundred and sixty miles—more than a hundred miles shorter. At least, that was what the traders called it to Fort Union, which was just above the mouth of the Yellowstone, as nearly as now is known; you must bear in mind that practically every one of the old fur posts was long ago wiped out. How? Well, largely by the steamboats themselves! The captains were always short of wood. They tore down and burned up first one and then another of the early posts. Settlers did the rest.

“At first, as early as 1841, it took eighty days to do that seventeen hundred and sixty miles upstream, and twenty-one days to run back downstream. In 1845 they did it in forty-two days up, and fifteen down. In 1847 it was done in forty days up, and fourteen days down; and they didn’t beat that much, if any.”

“That’s an average of about forty-four miles a day,” said Rob, who was doing some figuring on his notebook. “Going down, about one hundred and twenty-three miles.”

“Why, they beat our average!” complained John. “We didn’t climb her in much over forty, if that.”

“Well, we could pick the way easier, but she had more power,” said Rob. “Everybody knows a big boat beats a little one. But she didn’t beat us much, at that.”

“The Adventurer’s a good boat,” nodded Uncle Dick, “and I think on the whole we’ve got a pretty good idea of the travel of 1804 and 1805, or will have before we’re done.

“But now, one thing or two I want you also to bear in mind. Life isn’t all adventure. Commerce follows on the trail of adventure. The fur traders forgot the romance, and hurried in up the Missouri, as soon as they could. And what fur they did get! No wonder Great Britain was sorry to meet Lewis and Clark up here!

“There were a lot of important fur posts that fed into the Missouri. The mouth of the James River was a good post. Fort Pierre—on the Teton, down below—was the best post on the river except Union, at the Yellowstone. Pierre covered two and a half acres of ground, but Union was better built—she had twenty-foot palisades a foot square, and she stood two hundred and forty by two hundred and twenty feet, with stone bastions at two corners, pierced for cannon, and a riflemen’s banquette clear around inside.

“They were right in the middle of the Sioux and near the Blackfeet, and after the smallpox came on the river, the Indians got bitter and hated the thought of a white man. But they had only fur to trade for rifles and traps and blankets, and the white traders made the only market.