"You were making signals to somebody," exclaimed Adam, catching up the outlaw's rifle, and casting suspicious glances through the trees around him.
"Makin' signals to the air, then," replied Black Bill, sullenly. "Thar aint nobody within miles of here that I knows on."
But Adam had lived too long on the frontier, and knew too much about the outlaw to be easily deceived. He had distinctly seen the prisoner nodding his head, and with the quick instinct of one who had passed his life surrounded with foes of every sort, he scented danger. Frank might have been satisfied with Black Bill's reply, and the innocent, surprised expression on his face, but Adam was not. He jumped to his feet, and running across the brook, looked up at the top of the cliffs under which they had been sitting. As he did so, he passed behind the bowlder where the spy had been concealed but a moment before, and there he stopped, and leaning carelessly upon the rock, said, in a whisper to Frank, who had followed close at his heels:
"Don't exhibit any surprise, but look down at those leaves. Somebody has been here."
Frank looked, but could see nothing suspicious. Adam's trained eye, as keen as an Indian's, had, at a single glance, discovered signs of an enemy that Frank could not have found after an hour's careful search.
"I may have passed behind this rock when I first came to the brook," said he.
"If you did you never left those tracks," said Adam. "They were made by moccasins; and you've got shoes on. They were made by a white man, too, for the toes point out. If it had been an Indian, the toes would point in. A friend of Black Bill's was here not more than two minutes ago; and the sooner we get away from here the better it will be for us. What shall we do with our prisoner?"
"Let's take him with us, and compel him to show us the way to Fort Benton," replied Frank, astonished at his friend's skill in wood-craft, and at the coolness and deliberation with which he spoke.
"That would never do," said Adam, quickly. "His friends will be after us in less than five minutes, and he would shout to guide them in the pursuit. Besides, we are completely lost, and how could we tell whether or not he was guiding us to the fort? He would take us as straight to the Indian camp as he could go."
"Well, if we leave him here he will call for help the minute we are out of sight."