The sentinel uttered an exclamation, for the startling truth flashed upon him with the quickness of lightning.
Each apparent knot was the head of a native!
With amazing coolness, the New Englander brought his Winchester to a level, and bang, bang, bang, he shattered three of the knots in quick succession.
He would not have stopped the frightful work even then, had not the other targets disappeared.
Awaking to their danger, the warriors, dropped down so low in the water that the log intervened between them and the deadly marksman.
Still the tree with its terrible load was approaching land. The natives were swimming toward shore and pushing it in front of them.
Long stepped back and roused the professor, placing his mouth so close to his ear that he was able to apprise him of what was going on, without being heard by their enemies.
Grimcke bounded to his feet, rifle in hand.
"We'll take them as they come out!" he replied, instantly grasping the situation.
The log was drifting lower down at the same time that it neared the land. Determined to confront the savages the instant they came forth, the explorers hurried along the edge of the wood, so as to be on the spot when the landing should be made. It was well they did so, for a more astounding discovery than the first, instantly followed the movement.