“It appears to me,” said Roger presently, “as though someone had been along this way before us. See, some of the small branches are broken, and the growth beneath our feet seems to have been recently trodden. I expect we shall find that some of our men have been here before us, perhaps to look at those same caves themselves. If so, we can warn them to return immediately; and if they are in front of us it will give us a little longer, as it will take them some considerable time to get back to the boats from here.”
Thus reassured in their own minds—for there was always the danger of savages to consider,—they pressed on, but saw no further signs of the men whom they imagined to be in front of them.
“It is possible,” said Harry, his thoughts still dwelling upon the matter, “that if they have gone this way they are still at the caves. Or they may have gone back along the beach; for that, I suppose, is the nearest way of return. And if so, we shall not meet any of them coming this way; but we may overtake them.”
They had gone but a little distance farther when Roger looked up suddenly.
“Harry, I heard something whistle past my head a moment ago,” said he.
“Nonsense!” responded Harry. “What you heard was one of those small creatures they call ‘humming-birds’ flying past your ear.”
“I am certain it was not,” retorted Roger. “If it had been, I should have seen as well as heard him, and— why, there it is again!”
“Yes, you are right, Roger; I heard it myself that time. I wonder what it can be?” exclaimed Harry.
“I don’t know,” said Roger, “but it sounds very queer. Let us push on, or we shall have no time to explore those caves.”
They pushed forward for some little distance, and again heard, more than once, the same peculiar sibilant sound, as of something flying past them with great velocity; but they saw nothing, and could not account for the occurrence at all.