Despite the strong moonlight, he was unable to guess for a long time what it meant.  He first heard a splash, as though a body had fallen or been thrown into the water, and then, for several minutes, everything was still as before.

It was a source of annoyance to him that at this moment, when he hoped to keep his attention fixed on matters on the other bank, he should be disturbed by a sound among the trees directly behind him.  He, turned sharply and looked around, for the noise which had caught his attention was a footfall beyond all question.

But, if the youth was to be taken between two fires, he was ready.  The stranger nearest him could have no thought of his proximity, or he would have taken more care to suppress any noise.  Since he was so much nearer than him on the other side.  Ashman was forced to give his whole attention for the moment to the former’s approach.

His suspense was brief, for while he stood with rifle ready, a large puma, or American lion, emerged from a point a couple of rods away, walked in his stealthy fashion to the edge of the river and began lapping the water.

Ashman wished nothing with him in view of more important business elsewhere, and he, therefore, stepped softly back in the wood, before the beast finished drinking.

The puma quickly slaked his thirst, and then, raising his head, looked about him with an inquiring stare as though he scented something suspicious.  He gazed toward the other shore and finally swung himself lightly around, and trotted back to the forest.

Just before entering, he abruptly stopped and looked toward the spot where Ashman was concealed.  He offered a tempting shot, but it hardly need be said that the young man restrained himself, and the next minute the beast vanished.

CHAPTER XI.

A MYSTIFIED SENTINEL.

Jared Long, the New Englander, and Quincal, the native helper, were the sentinels on duty in the immediate vicinity of the camp.

The professor was wearied from a hard day’s work, and, feeling that everything possible had been done for the safety of all, stretched out upon his blanket on the soft ground and was soon asleep.

He expected to assume his duty as guardsman in the course of a few hours, and needed all the rest he could get before that time.

Bippo and Pedros were so disturbed by what they had witnessed, that, though they lay down at the same time, it was a good while before they closed their eyes in slumber.  Their homes were near the mouth of the Xingu, and, even at that remote point, they had heard so many fearful accounts of the ferocious savages that infested the upper portions of the river, that they never would have dared to help in an attempt to explore the region but for the liberal pay promised, and their unbounded faith in the white men and their firearms.