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?"

"By the sound--there!"

The amazement of the two may be understood, when they not only detected
the sound of footfalls, but discovered that instead of being at the
rear as both thought, they were in front!