“That is exactly what has been done,” added Dick, soberly. “See, you can even notice where the slit extends further than the break. This was not as much an accident as we thought, Roger. Some rascal, who knew what we expected to do, tried to bring about our destruction in the rapids!”

“But it must have been done since yesterday,” declared the other angrily, “for we looked over every inch of the skin of the boat then, and surely would have noticed the deep scoring of a knife blade.”

“There can be no doubt about that,” agreed Dick. “And the work was skillfully done in the bargain. Whoever made that cut expected that the boat would strike against rocks many times during the run of the rapids, and took chances that one of the blows would tear open the weak place. And that is what happened.”

“It would have gone much harder with us if we had not been most of the way down the descent,” said Roger, with a frown on his face. “But, Dick, who could the treacherous rascal be? As far as we know, we have not made a single enemy among the members of the party. Would one of our Indian friends have played such a mean trick on us, do you think?”

“No one but an enemy could have done it, Roger, because there was nothing to gain; for while some Indians might envy us our rifles these would surely be lost with us in the rapids and never recovered.”

“That makes the mystery worse than ever, then,” fretted the other lad, who was so constituted that among his boy friends down along the Missouri he had often gone under the name of “Headstrong Roger.”

“I have a suspicion, although there is really nothing to back it up, that I can see,” remarked Dick, reflectively, as though at some time in the past winter he had allowed himself to speculate concerning certain things which were now again taking possession of his mind.

“Dick, tell me what it is about, please,” urged his cousin, “because I’m groping in the dark, myself.”

“There is only one man that I know of who hates us bitterly,” commenced Dick, and instantly a flash of intelligence overspread the face of the other.

“Do you mean that French trader, François Lascelles?” he demanded.

“I was thinking of him, and his equally unscrupulous son, Alexis,” Dick admitted.

“But, when we captured them last fall, they were held prisoners in the camp until Mayhew, the scout, was well on his way down the river and could not possibly be overtaken. Then the party of Frenchmen was let go, with the solemn warning from Captain Lewis that if any of them loitered around this region they would be shot on sight. And Dick, all winter long you remember we have seen nothing of Lascelles, or indeed for that matter any other white man.”

“Still,” urged the other, “he may have come back here again when he found he could not overtake Mayhew and secure that paper. A man like François Lascelles hates bitterly, and never forgives. To be beaten in his game by a couple of mere boys would make him gnash his teeth every time he remembered it. Yes, something seems to tell me, Roger, that our old enemy has returned, and is even now in communication with some treacherous member of the expedition.”

“You mean his money has hired some one to play this terrible trick that might have cost us our lives; is that it, Dick?”

“It is only a guess with me,” replied the other, soberly; “but I can see no other explanation of this mystery.”

“But who could be the guilty man in the camp?” asked Roger. “We believed every one was our friend, from the two captains down to the lowest in line. It is terrible to suspect any one of a crime like this. How will we ever be able to find out about it, do you think?”

“We must begin to keep our eyes about us and watch,” advised Dick. “One by one we can cross the names off our list until it narrows down to two or three. Sooner or later we shall find out the truth.”

“Do you mean to tell Captain Lewis about the knife-slit along the bottom of our boat?” demanded Roger.

“It is our duty to tell him,” Dick declared. “The man who could stoop to such a trick as that, just for love of money, is not fit to stay in the ranks of honest explorers. Once we can show him the proof, I am sure Captain Lewis will kick the rascal out of camp. But I can see that you are beginning to shiver, Roger; so the first thing we ought to do now is to make a fire, and dry our clothes as best we may.”

“I was just going to say that myself, Dick, because this spring air is sharp, with little heat in the sun. To tell you the honest truth my teeth are beginning to rattle like those bones the Mandan medicine man shakes, when he dances to frighten off the evil spirit that has entered the body of a sick man. So let’s gather some wood and make a blaze.”

With that, both boys began to bestir themselves, first of all slapping their arms back and forth to induce circulation; after which they started to collect dry wood in a heap. At no time, however, did they let their precious guns leave their possession, for they knew that when fire-arms were needed it was usually in a hurry, and to save life.