It did not seem necessary to go far, and scarcely a furlong was passed when the Sauk selected a spot from which they could watch the river without exposing themselves to detection by any one on the further shore. If the Pawnees should return, as our friends were confident they would do, it was not likely they would delay long. It was an easy matter to summon all their warriors, and such as could not be accommodated in the canoe, could swim beside it.
At the moment that the Sauk secured a safe point from which to look out, Jack Carleton made the most important discovery that had come to the knowledge of any one of the three since starting on their journey.
Something on the ground just ahead and a little to one side of Hay-uta, caught his eye. The Sauk did not see it, and the boy did not suspect it was of any account. It was in obedience rather to a whim than to any reasoning impulse that he stepped aside and picked up the object.
"Great Cæsar!" he exclaimed. "It's Otto's cap!"
For a moment Jack stood transfixed, with the article held at arm's length, while the Sauk stared in turn, as if he thought the youth was beside himself.
But the lad was too familiar with that headgear to be mistaken. He turned it over and over, held it close to his face and scrutinized every particle of it; it was the same peaked hat which poor Otto had worn so long, and it was on his head when he and Jack—both captives—parted company weeks before.
How long the hat had lain where it was picked up, could not be told. Its make was such that, while the owner had worn it several years, it was still good for an indefinite time longer. A day or a month of exposure would make little difference in its appearance.
When Jack had recovered from his amazement, he and Hay-uta examined the immediate vicinity. The action of the youth, and the emotion he displayed, told the story to the Sauk, who did not fail also to see the value of the clew that had fallen into their hands.
Ten feet from where the cap was found lay a small decayed tree. It had probably been blown down during some gale. The suggestion presented itself that Otto Relstaub was sitting on this support, when he either flung the hat from him, or some one else did so. That which the friends wished to find now was the footprints left by the lad when he went away: they would tell the story as nothing else could.
If the missing boy had gone within the preceding two or three days, the keen vision of the Sauk could see and follow the trail. Recognizing his immeasurably superior skill, Jack remained seated on the tree and nodded to Hay-uta to push his search.