"Why, would you dare tackle a grizzly?" smiled their friend. John did not say much. "These boys have done it," replied their uncle for them. "I'd hate to be the bear. They shoot straight, and the rifles they have are far more powerful than the ones the first explorers had." "We'll call this exploring," said Jesse, with sarcasm. "I'll have to get help to hang up my antelopes so they'll cool out. "But, anyhow," he added, "this is as much fun as plugging along among the sand bars in the motor boat. We beat the oars, and now this gas wagon beats our boat motors!" "Uncle Dick," suddenly interrupted Rob, "we've been talking about the fur trade on the river a hundred years ago. I understand the fur posts were supplied by steamboats, at the height of the fur trade, anyhow. Now, how long did it take a steamer in those days to make the run, say, from St. Louis to the mouth of the Yellowstone?" "That's easy to answer," his uncle replied. "The records and logs of some of the old boats still exist in St. Louis, and while I was there I looked up some of them. "Now as nearly as I can learn there was no exact way of estimating distances by any of those travelers--the speedometer was not invented, nor the odometer, nor the ship's log. Now I don't know how the steamboat captains got at it, but they kept a daily log of distance, and they had the different stopping places all logged for distance. We make it a little less than sixteen hundred miles to Mandan. The _Journal_ makes it sixteen hundred and ten--close enough. The river chart calls it fourteen hundred and fifty-two to the bridge; over fifty miles below the Mandan villages. "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."