He did not know what to make of it.  There was something so uncanny about the whole business, that a strange distrust and uneasiness took possession of him.  It could not be that the natives had deceived him and were anxious to place the Xingu between them and the fierce savages who had handled the whites so roughly.  Bippo and his comrades had shown a loyalty from the first which gave their employers the fullest confidence in them.

The canoe was almost against the bank, where something of the bewilderment of Ashman seemed to enter the head of Bippo.  He spoke to his companions and the three ceased paddling.  Ashman had done so a moment before and was scanning the bank with a searching but vain scrutiny.

“You must have been mistaken,” he said in a low voice; “they could not have swam the river and they had no other way of crossing.”

“We seed ’em—­motion dat way,” and the native beckoned with his right arm, just as a person would do when signaling another to approach.

“I can’t understand it,” replied Ashman, with a shake of his head.

His doubts were confirmed, when he recalled that the professor and Jared Long had gone up the bank of the river with the purpose of learning the extent of the rapids.  It followed, therefore, that if they had made their way to the other shore, it must have been at a point so far above the angry waters that there was no danger of being caught in the furious current.

He was turning over these troublous thoughts, when Bippo, who was facing the bank they had left, uttered an expression of dismay and extended his arm toward the shore behind them.

Ashman turned his head, and there in the moonlight he saw Professor Grimcke and the New Englander standing on the land and motioning to them to return.

“Yes—­dat de way he do—­he move arm like dat,” said Bippo; “we hurry to go to him, den he ain’t here—­but dere.”

Ashman could not doubt that the servant believed the extraordinary assertion he had just made, and such being the case, the startling truth was manifest; they had seen two strangers whom they mistook for their own friends, and these strangers had beckoned them to paddle the canoe to the other shore where they were awaiting them.

If such were the fact—­and he did not doubt it—­a new mystery confronted him.

Who were the white men and strangers? and why had they disappeared when approached by the canoe and its occupants?

Ashman ordered the servants to turn the craft about and return to the shore they had left with all speed.  While doing so, and while Grimcke and Long were doubtless wondering what had got into the heads of the others, the young man wrought himself into a most uncomfortable condition of mind.

He questioned Bippo more particularly as to the appearance and actions of the strangers.  It was clear that he, as well as the other two, still believed the couple on the opposite bank were Grimcke and Long; though when reminded that it was impossible that they could have crossed and recrossed the stream in such a brief time, and without any means except that of swimming, they only shook their heads, signifying that, though they could not explain that feature of the strange business, they would not yield their belief.