“Why, the river we’ve reached. It lies to the left of our course. If it was the Sunflower, it would lie to the right. Anyhow, it runs into the Yazoo, and that’s all we ask of it.” “By the way, Ed,” said Irv, “how long is the Yazoo?” “I don’t know, I’m sure,” said Ed. “I’ll get the map after supper, and look.” “Don’t bother,” said Phil. “The navigable part of it is one hundred and seventy-five miles long.” “How did you come to know that?” asked Will. “I thought Ed was the geographer of this expedition.” “So he is. But I’m captain, worse luck to it, and it’s my first business to know what lies ahead. So I looked this thing up on the map. The Yalobusha and Tallahatchie run together somewhere near a village called Greenwood, which is probably a hundred feet or so under water just now,--we may even float over the highest steeple in that interesting town, when we get to it,--and those two streams form the Yazoo. By the way, that little side issue of a river happens to be considerably longer, in its navigable part, than one of the most celebrated rivers in the world--the Hudson.” “You don’t mean it?” exclaimed Irv, for once surprised out of his drawl. “Maybe I don’t. But I think I do. Ask Ed to study it out. I’m too tired to talk. I’m going to sleep for ten minutes now. Wake me up at the end of that time. Don’t fail!” With that the exhausted boy rolled into a bunk, and in an instant was asleep again. Ed got out his maps and studied them for a while. “He’s right, boys,” said the older one, after some measurements on the map. “Of course he is,” said Constant. “He’s got into the habit of being right since we chose him to be ‘IT’ for this trip. But go on, Ed. Tell us about it.” “Well,” said Ed, still scrutinizing the map, “the navigable part of the Hudson, from New York to Troy, is about one hundred and fifty-six miles long. The navigable part of the Yazoo is, as Phil said, one hundred and seventy-five miles long. Oh, by the way--” “What is the thought behind that exclamation?” said Irv, when Ed paused; for Irv’s spirits were irrepressible. “It just occurs to me,” said Ed, “that this wonderful river of ours, the Mississippi with its tributaries, is almost exactly one hundred times as long--in its navigable parts--as the greatest commercial river of the East.” “In other words,” said Irv, “the East isn’t in it with us. Its great Hudson River would scarcely more than make a tail for the Mississippi below New Orleans. It would just about stretch from Cincinnati to Louisville. It would cover only a little more than half the distance from St. Louis to Cairo, or from Cairo to Memphis.” “True!” said Ed, “and pretty much the same thing is true of every great river in Europe. Not one of them would make a really important tributary of our wonderful river. All of them put together wouldn’t compare with the Ohio and its affluents.” “Phil’s ten minutes are up,” said Will. “I hate to wake him, but that was his order.”