Suddenly Fred started and almost uttered an exclamation. In his nervous, apprehensive state, he was sure that one of their dusky foes had leaped from the side of the path and was crouching in front.
He drew his pistol and waited for the assault, which he was confident would come the next moment; but the seconds passed and all remained profoundly still.
With his weapon ready for instant use, he advanced a pace or two, touching the sailor as a command for him to remain motionless; but the chivalrous fellow would not obey, and was close behind him, when he stooped down and placed his hand on a piece of decayed limb that had fallen into the path.
"What a mistake," muttered Fred, with a sigh, as he shoved it aside with his foot, explaining its nature to the wondering Johnston.
But it was only simple prudence to maintain unceasing vigilance, and he did not permit the error to lessen his watchfulness. It was rather the reverse.
But the explorers were threading their way through a labyrinth of peril, the like of which they had never encountered before.
Fred had not gone a hundred yards further, when his companion once more caught his arm, and he turned about as before to learn the cause.
"What have you heard?" he asked, with his mouth almost against the ear of the other.
"There are some of 'em behind us, certain sure!"
"How do you know there are more than one?"