CHAPTER XIII.

THE HOLE IN THE AIR.

Little Rifle and Harry Northend stood in the cavern, gazing in wonder at the pale, glimmering point of light, neither able to guess what it could mean.

The first supposition that it was a star was dissipated the next instant by the consciousness that such a thing was a physical impossibility, and besides which its appearance was different. It was apparently several inches in diameter, something like a hundred yards distant, and at a point considerably above their heads.

Heeding the terrible warning that they had received, the lads advanced with great circumspection. Harry willingly relinquished the place of leader to his companion, knowing how much more careful and skilled he was in business of this kind, and how much more likely he was to detect its nature.

Not until they were directly beneath the strange appearance did they comprehend what it meant. By that time they found that it was fully a foot in diameter, and that it was something like fifty feet above their heads.

“It is a window in the cavern,” said Little Rifle, “and we are looking through into the world above us. Let us draw aside to the side of the cavern, where we can rest and look up at the hole without stretching our necks so.”

That which had caught their eyes was simply daylight, looking dim, pale and weird as it penetrated into the gloom of the cavern.

“Well, that is something,” said Harry; “we can take a peep at daylight when we get tired of darkness, and can keep track of the passing days and nights, if we have got to live the life of a hermit, for some weeks or months.”

Little Rifle, greatly wearied with their uncommon exertions, now stretched out in an easy position, with his head leaning upon his elbow, and looking up at the opening for several minutes, as if to think out some mode of escape to the upper world.

They had lain down in their chosen nook but a short time, when it became evident that the light overhead was slowly growing paler and dimmer. This of course they attributed to the departure of daylight and the coming of night. It continued steadily to fade, until it vanished from view altogether, and then they knew that darkness reigned above and below alike.

Tired and wearied as were the lads, it was not long before they felt a drowsiness stealing over them, against which neither made any struggle. Both lying there felt how great was their dependence upon Heaven to bring them out of their almost hopeless difficulty, and with a prayer for the protection and guidance of their Heavenly Father, both sunk off into a soft, refreshing slumber.

The training and life of Little Rifle made his sleep always light, although it was as refreshing as nature intended, and so it came about that he had remained unconscious but a short time, when he opened his eyes, with the certainty that something from without had occurred to cause him to do so.

Without moving from his position, he raised his head and listened.

Nothing but the dull, hollow roar of the cavern filled his ears, and that was like the very depth of silence itself. Not even the soft rustling of the night-wind among the trees far above his head could be detected.

Applying his ear to the earth he instantly heard a regular _tip, tap, tip, tap_, as if made by the dropping of water, but which a moment’s listening satisfied him was produced by another cause.

The uncertain character of the noise made it impossible to tell whether it was near or far, but he judged that it was a long way off.

But, suddenly he started up, and reaching over shook his companion into wakefulness, for he had discovered the meaning of the singular sound, and it was high time that they were on their guard!

“’Sh!” whispered Little Rifle; “there’s some one in the cavern besides us,” he replied, in the same cautious tone. “I can hear two persons walking, and they are coming this way!”

The steps continued their approach, until, as near as the boys could judge, they were directly beneath the opening, and something like fifty feet from the spot where they were crouching upon the ground. Here they paused, and one of them said:

“Give the signal, Tom!”

A whistle followed, that screeched out like that of a locomotive engine, awakening strange echoes through the cavern, and only a few seconds had elapsed when a fainter reply came back from above their heads. The window was closed by the obtrusion of some dark body.

“Helloa! Tom, is that you down there?” some one called through the opening.

“Of course. Come, be lively now, and let down that rope.”

“All right; there it comes; look out for it!”

The listening lads soon heard sounds as if made by a person in drawing himself up “hand-over-hand” by means of the rope. Such in truth was the case, and a few minutes after they saw two bodies disappear, one by one, through the skylight.

What they had heard of course told them that the three men whose voices they had heard were not Indians but white men. What their errand was in the cavern, it was hard to conjecture, as was also the question whether it would be prudent to advance and make their situation known to them.

They could catch the muttering mumbling of words far above, but could not understand a syllable uttered. In a few moments the sound of voices ceased altogether, for the men evidently had gone away.

While Little Rifle stood all attention, Harry was groping around with his hands.

“By jingo! they have left the rope hanging down!” he exclaimed, in a delighted whisper, as he pushed it toward his friend. “I wonder if they didn’t do that on purpose for us?”

The young trapper grasped it in his hands, and found that it was an ordinary hemp rope reaching to the floor of the cavern, and capable of bearing a heavy strain.

“Ha! ha!” softly laughed Little Rifle, “here is our deliverer,” and without a word of explanation the resolute lad sprung to the ascent, and, hand-over-hand like a sailor, went up the rope with great agility.

Harry, with an anxiety that may well be imagined, stood peering upward in the gloom, awaiting the result of this perilous venture on the part of his friend.

He held the rope grasped in both of his hands, noting, by its swaying and trembling, the progress made by the daring young trapper.

By and by the swaying of the rope ceased, by which he knew that Little Rifle was at the top.

Then Harry himself began the ascent, and had reached about half-way to the top, when Little Rifle called out, evidently in a subdued voice:

“Hello, Harry! are you down there?”

“No, I ain’t; I’m half-way up,” he answered, in an imprudently loud tone.

“Come on as fast as you can; the way is clear, but there’s no telling how long it will remain so.”

Spurred on by this, Harry hastened on, and was soon up to the hole. Taking him by the hand, Little Rifle dragged him from beneath the clump of bushes which served as a screen to the entrance to the cavern, and then, catching him by the arm, he compelled Harry to follow him away from the vicinity.

The moon was high in the sky, and the night was clear and balmy, inspiring a delicious happiness through the hearts of the boys, as they realized that they were treading the earth again, and all present danger was past.

They could hear the murmur of the river, flowing near them, and making their way toward it, found, as they had suspected, that the cavern extended a long ways underground, and had led them a goodly distance away.

Fortunately they were upon the right side, and it only remained for them to get over the intervening distance between them and the cabin where old Robsart made his head-quarters.