We were half numbed with the cold, but I found now that, in spite of our troubled dreams and its apparent brevity, our sleep must have continued for a long time, for our clothes were nearly dry.

“Now, then, Mas’r Harry,” said Tom, “never mind no shrieks and cries; let’s eat what there is in that bag and drink what there is in that bottle, and then go on our voyage of discovery.  It will give us strength for the job, besides being ever so much easier to carry.  If anything queer comes near us we’ve got our pistols, so let them look out.”

In spite of the feeling of tremor caused by the mysterious cries I was eager enough to move, and we began to climb up once more through the crack, after stepping back to the vault, holding up our candles, and making sure that by no possibility we had overlooked the raft.

As to its floating away I felt that it would not go very far on reaching the end of the tunnel, there were too many obstacles in the way in the shape of great boulders to block up the stream; so that hope of relief was but faint there even if a search was commenced.

There was no raft in sight; nothing but the strange, troubled water, ever bubbling and leaping up; and with a shudder, as we thought of the struggle we had had, we turned away, but not without seeing that the sand strip was now about half bare.

It was no time for being nervous.  We knew that to live we must find a means of exit while our candles lasted, so started once more to thread our way along through the rift and right on to the huge cavern where the cascade of water came thundering down.

Here we halted for a time to gain breath, and then set to work to thoroughly explore the place; so we pushed on nearer and nearer, to find that, as we expected, we could pass right round behind the waterfall, over the slippery, wet stones, worn into seams, as if at one time the stream had rushed down them; but no trace of rift or passage could we find save one small crevice through which it seemed possible that a body might be squeezed.

“Never mind, Mas’r Harry, that can’t be the way; let’s try farther round this other side.”

Tom led now and I followed, leaving the cascade behind us, and thoroughly examining the other side of the amphitheatre, but without avail; when we sat down, worn out, about opposite to the rift where we had entered, too disheartened to speak, till Tom said: 

“We shall have to try and crawl through that hole, Mas’r Harry ­there, under the waterfall.”

“A dog could hardly do it, Tom,” I said bitterly, and then I started.  “Stop a moment,” I cried.  “That was a regular crack or split in the rock that we came through, Tom; such a one as might have been made by an earthquake.”

“Sure it was, Mas’r Harry; but you don’t think as another one has come and shut it up, do you?”

“No, no, Tom,” I cried, leaping up and forgetting my fatigue; “but why should not that crack be continued on this side ­here, just opposite where we are?  Come, climb higher with me, and let us have another try.”

My thought was a bright one; for far up, just where the side of the amphitheatre began to curve into the dome which formed the roof, we found a crack answering to the one through which we entered on the other side; and squeezing ourselves through, we found that we were in another narrow passage ­so narrow, though, that we proceeded with great difficulty.

“This must be the way out, Tom,” I said.

“Or the way in, Mas’r Harry,” said Tom; “one of them two.  Anyhow, though, we shall soon see.”

Not so soon, though, as Tom expected; for we crept on and climbed for quite a couple of hours, winding and doubling about, before the rift opened out, sloping, too, at the same time, so that walking became out of the question; and we climbed slowly down till we lost sight of roof and sides.  Then on and on, slowly and carefully, where a false step would have sent us gliding we knew not where; and then we stopped, aghast, with a fearful chasm at our feet, to awake to the fact that we had climbed down to the extreme edge of an awful precipice, while, on holding up our lights, there before us was darkness, black and impenetrable, above, around, beneath.

The same thought occurred to both, and in a whisper we gave utterance to that thought together, though in different words.

“Tom, we’ve come round to another part of the great black gulf.”

“Mas’r Harry, this is the same place where we pitched down the big stone.  Let’s try another.”

More to prove the truth of our thought than anything else, I assented; and finding a good-sized lump, Tom hurled it outwards with all his might, and then we listened as we had listened before, to hear it at last strike water at a profound depth, with the same roar of echoes to make us shrink shuddering back.

“It is the same place, Tom,” I said, speaking hoarsely, for this was another damp to our hopes.

There was apparently no chance even of reaching the rocky point where we had stood the day before, for that point stood out alone, and I could not see how it could be reached; but in a dull, despondent way, I thought that we would try to the last; and shrinking back a few yards from the edge of the precipice, we began to climb along the side, in the hope of finding some outlet in that direction; for could we but reach that point by any means we were safe.

Ten minutes’ climbing in a state of extreme horror, with the loose fragments of rock slipping from beneath our hands and feet, to roll rattling over the edge of the vast chasm, and then we were brought to a standstill; for there, right in front, was a bare, smooth, perpendicular wall of rock, inexorable as fate itself.

We turned and began to climb back along the horrid slope, when, with a sensation of horror that I hardly dare to recall, I felt my legs slip, my hands, torn, wet, and bleeding as they were, to glide over the stone to which I clung; and, with a feeble cry for aid to Tom, I gave myself up for lost.

With a shriek like that which might have been expected to have emanated from some wild beast, Tom leaped to my side, caught at me, and then, clinging together, we continued our downward course for what seemed an interminable length of time, when there was a sudden stoppage.  Tom’s feet rested in a cleft of the rock, and he held me fast, as I lay gasping, with my legs hanging for some distance over the frightful chasm.

For full five minutes we did not either of us move, since it seemed that the slightest attempt to alter our position must result in a plunge into the darkness yawning to receive us.

One candle was extinguished, but the other lay guttering and flaring some twenty feet above us, wasting rapidly, and casting its feeble, weird light upon where we clung.

We neither of us spoke, but softly feeling about, I at length got my fingers in a chink of rock, which gave me courage to move my legs, so that at last they rested upon a rough point or knob.  Then, by Tom’s guiding, my other hand found a hole, and by an effort I climbed on to the slope, to lie panting and waiting for nerve.

Help me Tom could not from his position, and had I not stirred myself I must have fallen at last; but he had well paid the debt he owed me for my last night’s efforts, as I told him when we had cautiously made our way back up the slope in a diagonal direction to where the rift opened, to sink down at last, breathless and thankful, in the narrow way; glad even to be beyond reach of the influence of the horrible gulf, which had for me an attraction that was appalling.

We were very quiet now, as we half sat, half lay upon the rocky bottom of the crack, till our strength was somewhat renewed after our late efforts, when, dragging myself up, I wiped the clammy dew from my forehead, and Tom followed my example.

“Tom,” I exclaimed, “inaction means death.  Let’s try that hole behind the fall.”

“Right, Mas’r Harry,” said Tom, essaying to be cheerful.

And without another word he rose, took his candle from the niche in which he had placed it, and together we made our way back into the amphitheatre.  Then we climbed over the blocks to behind the fall, where, going down upon his knees, Tom held his candle in at arm’s-length, and then essayed to creep in at the little opening.

I looked on anxiously as his head and shoulders disappeared, then his whole body; and I was preparing to follow him when he wriggled himself back, to face me with a sad shake of the head.

“No good, Mas’r Harry ­a baby couldn’t go through there.”

I took his word, and led the way back till we were clear of the mist shed by the fall, and then I set to and tried if the great problem of our escape could not be solved; and at last when all hope was ready to expire in my bosom the solution came.

We were sitting, sad and dejected, worn by our long toil, when suddenly we were startled by a shriek similar to those which we had heard upon our awaking.

Tom pressed close to me, and I must confess to a strange sensation of awe, as now, one after another, these wild cries came ringing out of the darkness around.  Now near, now far-off, and fading away as it were, till one was uttered close by my ear, and I saw a shadowy form sweep past the light shed by our one poor feeble candle; then another and another; when, angry with myself for my superstitious dread, I exclaimed aloud: 

“Why, they’re birds!”

“Birds they are!” cried Tom gently.  “But are they real birds, Mas’r Harry?”

“Real? yes, Tom!” I exclaimed excitedly.  “And there must be some other way of entrance, for I saw one disappear close by the falling water.  Yes, and there goes another!” I cried, as I held up the light.  “Tom ­ Tom, they are the messengers of life!  There is a way out yet!”